The hamstring muscle group is the most frequently injured, representing
approximately 12 to 24% of all athletic injuries.1,2 These injuries may be due to
disproportionate training performed for the quadriceps,3 with hamstring strains
occurring more frequently in those who demonstrated hamstring weakness, and
lower hamstring-to-quadriceps strength ratios.2 Thus, hamstring strength is impor-
tant for athletic performance and injury prevention in a variety of sports.
Muscle activation during various hamstring exercisesFernando Farias
The main findings of this investigation demonstrate that
there are significant differences in activation within muscles
when comparing all exercises. Although one might expect
similar activation for a given muscle for activities of similar
kinematics, such as the prone leg curl and glute-ham raise,
this is not the case with the data herein
Acute effect of different combined stretching methodsFernando Farias
The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up,
on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height:
177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49
years) was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a
warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were
divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The
warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min
stretching program (except for the no-stretching protocol), and 2 min rest periods, followed by the 10 and 20 m sprint
test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic
stretching compared with static, combined, and no-stretching protocols. There were also significant differences between
the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed
better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more
force for a faster execution.
The four hamstrings muscles are: the biceps femoris (long head), the biceps
femoris (short head), the semitendinosus, and the semimembranosus. The
two biceps femoris muscles are located on the lateral part of the thigh.
The semitendinosus and the semimembranosus are located on the medial
part of the thigh.
The hamstrings are made up of three
muscles: semitendinosus (ST), semimembranosus (SM) and the biceps femoris
(BF). ST is in the back, inner part of your thighs. SM is in the back, outerish part
of your thighs along with the BF. [Do not get the biceps femoris in your legs
confused with the biceps brachii in your arm..] This group of muscles, in general,
allows us to curl our legs and bring our shins to our butt.
Os resultados atuais indicaram que a ocorrência de lesões de isquiotibiais podem estar associadas a uma mudança hierárquica na distribuição da atividade metabólica dentro do complexo muscular do isquiotibial após o trabalho excêntrico em que o Semitendinoso provavelmente deveria tomar a parte principal, seguido pelo BÍceps Femural e Semimembranoso. Quando o BF aumenta sua contribuição e é ativado em uma extensão proporcionalmente maior, o risco de sofrer uma lesão do isquiotibial pode aumentar substancialmente.
Epidemiological studies have consistently shown hamstring
strain injuries (HSIs) to have a high prevalence rate in many
sports, such as sprinting (11%; Lysholm & Wiklander, 1987),
Australian Rules Football (16–23%; Orchard, 2001; Orchard,
Marsden, Lord, & Garlick, 1997) and football (12–14%:
Ekstrand, Hagglund, & Walden, 2011; Hawkins, Hulse,
Wilkinson, Hodson, & Gibson, 2001). The epidemiology and
aetiology of HSI in football has received extensive attention in
the scientific literature (Ekstrand et al., 2011; Woods et al., 2004),
given the economic burden associated with professional
players missing training and competitive fixtures (Woods,
Hawkins, Hulse, & Hodson, 2002). b
Melhorar ou até mesmo manter o desempenho atlético em jogadores de esportes de equipe competitivos durante o longo período da temporada é um dos maiores desafios para qualquer treinador comprometido. Tempo muito limitado está disponível entre as partidas semanais para introduzir sessões intensivas de treinamento de força e poder, com uma freqüência normal de 1-2 unidades por semana. Este fato estimula a busca de métodos de treinamento mais eficientes capazes de melhorar uma ampla variedade de habilidades funcionais, evitando ao mesmo tempo os efeitos de fadiga.
Differences in strength and speed demands between 4v4 and 8v8 SSGFernando Farias
Small-sided games (SSGs) have been extensively used in training
footballers worldwide and have shown very good efficacy in
improving player performance (Hill-Haas, Dawson, Impellizzeri,
& Coutts, 2011). As an example, it has been shown that the
technical performance (Owen, Wong del, McKenna, & Dellal,
2011) and physical performance (Chaouachi et al., 2014; Dellal,
Varliette, Owen, Chirico, & Pialoux, 2012) of footballers can be
enhanced using SSG-based football training programmes.
In the last two decades, extensive research has been pub-
lished on physical and physiological response during SSGs in
football (for refs, see Halouani, Chtourou, Gabbett, Chaouachi,
& Chamari, 2014). It was found that the time-motion charac-
teristics of SSGs could vary greatly depending on certain
structural (e.g., pitch size, number of players, type and number
of goals) and rule (e.g., number of ball touches) constraints.
For example, it was observed that higher maximum speeds are
reached during SSGs played on bigger pitches (Casamichana &
Castellano, 2010). Furthermore, heart rate (HR) and lactate
concentrations were shown to be sensitive to structural and
rule changes in SSGs.
Muscle activation during various hamstring exercisesFernando Farias
The main findings of this investigation demonstrate that
there are significant differences in activation within muscles
when comparing all exercises. Although one might expect
similar activation for a given muscle for activities of similar
kinematics, such as the prone leg curl and glute-ham raise,
this is not the case with the data herein
Acute effect of different combined stretching methodsFernando Farias
The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up,
on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height:
177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49
years) was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a
warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were
divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The
warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min
stretching program (except for the no-stretching protocol), and 2 min rest periods, followed by the 10 and 20 m sprint
test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic
stretching compared with static, combined, and no-stretching protocols. There were also significant differences between
the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed
better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more
force for a faster execution.
The four hamstrings muscles are: the biceps femoris (long head), the biceps
femoris (short head), the semitendinosus, and the semimembranosus. The
two biceps femoris muscles are located on the lateral part of the thigh.
The semitendinosus and the semimembranosus are located on the medial
part of the thigh.
The hamstrings are made up of three
muscles: semitendinosus (ST), semimembranosus (SM) and the biceps femoris
(BF). ST is in the back, inner part of your thighs. SM is in the back, outerish part
of your thighs along with the BF. [Do not get the biceps femoris in your legs
confused with the biceps brachii in your arm..] This group of muscles, in general,
allows us to curl our legs and bring our shins to our butt.
Os resultados atuais indicaram que a ocorrência de lesões de isquiotibiais podem estar associadas a uma mudança hierárquica na distribuição da atividade metabólica dentro do complexo muscular do isquiotibial após o trabalho excêntrico em que o Semitendinoso provavelmente deveria tomar a parte principal, seguido pelo BÍceps Femural e Semimembranoso. Quando o BF aumenta sua contribuição e é ativado em uma extensão proporcionalmente maior, o risco de sofrer uma lesão do isquiotibial pode aumentar substancialmente.
Epidemiological studies have consistently shown hamstring
strain injuries (HSIs) to have a high prevalence rate in many
sports, such as sprinting (11%; Lysholm & Wiklander, 1987),
Australian Rules Football (16–23%; Orchard, 2001; Orchard,
Marsden, Lord, & Garlick, 1997) and football (12–14%:
Ekstrand, Hagglund, & Walden, 2011; Hawkins, Hulse,
Wilkinson, Hodson, & Gibson, 2001). The epidemiology and
aetiology of HSI in football has received extensive attention in
the scientific literature (Ekstrand et al., 2011; Woods et al., 2004),
given the economic burden associated with professional
players missing training and competitive fixtures (Woods,
Hawkins, Hulse, & Hodson, 2002). b
Melhorar ou até mesmo manter o desempenho atlético em jogadores de esportes de equipe competitivos durante o longo período da temporada é um dos maiores desafios para qualquer treinador comprometido. Tempo muito limitado está disponível entre as partidas semanais para introduzir sessões intensivas de treinamento de força e poder, com uma freqüência normal de 1-2 unidades por semana. Este fato estimula a busca de métodos de treinamento mais eficientes capazes de melhorar uma ampla variedade de habilidades funcionais, evitando ao mesmo tempo os efeitos de fadiga.
Differences in strength and speed demands between 4v4 and 8v8 SSGFernando Farias
Small-sided games (SSGs) have been extensively used in training
footballers worldwide and have shown very good efficacy in
improving player performance (Hill-Haas, Dawson, Impellizzeri,
& Coutts, 2011). As an example, it has been shown that the
technical performance (Owen, Wong del, McKenna, & Dellal,
2011) and physical performance (Chaouachi et al., 2014; Dellal,
Varliette, Owen, Chirico, & Pialoux, 2012) of footballers can be
enhanced using SSG-based football training programmes.
In the last two decades, extensive research has been pub-
lished on physical and physiological response during SSGs in
football (for refs, see Halouani, Chtourou, Gabbett, Chaouachi,
& Chamari, 2014). It was found that the time-motion charac-
teristics of SSGs could vary greatly depending on certain
structural (e.g., pitch size, number of players, type and number
of goals) and rule (e.g., number of ball touches) constraints.
For example, it was observed that higher maximum speeds are
reached during SSGs played on bigger pitches (Casamichana &
Castellano, 2010). Furthermore, heart rate (HR) and lactate
concentrations were shown to be sensitive to structural and
rule changes in SSGs.
The effects of self-myofascial release using a foam roll or roller massager on joint range of motion, muscle recovery, and performance: a systematic review
Effects of Velocity Loss During Resistance Training on Performance in Profess...Fernando Farias
To analyze the effects of two resistance training (RT) programs that used the same relative loading but different repetition volume, using the velocity loss during the set as the independent variable: 15% (VL15) vs. 30% (VL30). Methods: Sixteen professional soccer players with RT experience (age 23.8 ± 3.5 years, body mass 75.5 ± 8.6 kg) were randomly assigned to two groups: VL15 (n = 8) or VL30 (n = 8) that followed a 6-week (18 sessions) velocity-based squat training program. Repetition velocity was monitored in all sessions. Assessments performed before (Pre) and after training (Post) included: estimated one- repetition maximum (1RM) and change in average mean propulsive velocity (AMPV) against absolute loads common to Pre and Post tests; countermovement jump (CMJ); 30-m sprint (T30); and Yo-yo intermittent recovery test (YYIRT).
High chronic training loads and exposure to bouts of maximal velocity running...Fernando Farias
The ability to produce high speeds is considered an important
quality for performance, with athletes shown to achieve 85–94% of
maximal velocity during team sport match-play.3 Well-developed
high-speed running ability and maximal velocity are required of
players during competition in order to beat opposition players
to possession and gain an advantage in attacking and defensive
situations.
EFFECTS OF STRENGTH TRAINING ON SQUAT AND SPRINT PERFORMANCE IN SOCCER PLAYERSFernando Farias
We have demonstrated that a simple in-season strength training program resulted in an improvement in maximal back squat performance, which was reflected in improve- ments in short sprint performance, as identified by a decrease in sprint time over 5, 10, and 20 m, in professional soccer players, in line with the hypotheses. Furthermore, the changes in relative 1RM squat strength demonstrate strong associations with the changes in 5 (r = 0.62), 10 (r = 0.78), and 20-m (r = 0.60) sprint performances.
Sprint running acceleration is a key feature of physical performance in team sports, and recent
literature shows that the ability to generate large magnitudes of horizontal ground reaction force
and mechanical effectiveness of force application are paramount. We tested the hypothesis that
very-heavy loaded sled sprint training would induce an improvement in horizontal force
production, via an increased effectiveness of application. Training-induced changes in sprint
performance and mechanical outputs were computed using a field method based on velocity-
time data, before and after an 8-week protocol (16 sessions of 10x20-m sprints). 16 male
amateur soccer players were assigned to either a very-heavy sled (80% body-mass sled load)
or a control group (unresisted sprints). The main outcome of this pilot study is that very-heavy
sled resisted sprint training, using much greater loads than traditionally recommended, clearly
increased maximal horizontal force production compared to standard unloaded sprint training
(effect size of 0.80 vs 0.20 for controls, unclear between-group difference) and mechanical
effectiveness (i.e. more horizontally applied force; effect size of 0.95 vs -0.11, moderate
between-group difference)
To examine the acute effects of generic (Running Drills, RD) and specific (Small-
Sided Games, SSG) Long Sprint Ability (LSA) drills on internal and external load of male
soccer-players. Methods: Fourteen academy-level soccer-players (mean±SD; age 17.6±0.61
years, height 1.81±0.63 m, body-mass 69.53±4.65 kg) performed four 30s LSA bouts for
maintenance (work:rest, 1:2) and production (1:5) with RD and SSG drills. Players’ external-
load was tracked with GPS technology (20Hz) and heart-rate (HR), blood-lactate
concentrations (BLc) and rate of perceived exertion (RPE) were used to characterize players’
internal-load. Individual peak BLc was assessed with a 30s all-out test on a non-motorized
treadmill (NMT). Results: Compared to SSGs the RDs had a greater effect on external-load
and BLc (large and small, respectively). During SSGs players covered more distance with
high-intensity decelerations (moderate-to-small). Muscular-RPE was higher (small-to-large)
in RD than in SSG. The production mode exerted a moderate effect on BLc while the
maintenance condition elicited higher cardiovascular effects (small-to-large). Conclusion:
The results of this study showed the superiority of generic over specific drills in inducing
LSA related physiological responses. In this regard production RD showed the higher post-
exercise BLc. Interestingly, individual peak blood-lactate responses were found after the
NMT 30s all-out test, suggesting this drill as a valid option to RD bouts. The practical
physiological diversity among the generic and specific LSA drills here considered, enable
fitness trainers to modulate prescription of RD and SSG drills for LSA according to training
schedule.
Bilateral and unilateral vertical ground reaction forcesFernando Farias
The purposes of this study were to assess unilateral and bilateral vertical jump performance
characteristics, and to compare the vertical ground reaction force characteristics of the impulse and landing
phase of a vertical jump between the dominant and non-dominant leg in soccer players.
Impact of the Nordic hamstring and hip extension exercises on hamstring archi...Fernando Farias
The architectural and morphological adaptations of the hamstrings in response to training
33 with different exercises have not been explored. PURPOSE: To evaluate changes in biceps
34 femoris long head (BFLH) fascicle length and hamstring muscle size following 10-weeks of
35 Nordic hamstring exercise (NHE) or hip extension (HE) training. METHODS: Thirty
36 recreationally active male athletes (age, 22.0 ± 3.6 years, height, 180.4 ± 7 cm, weight, 80.8 ±
37 11.1 kg) were allocated to one of three groups: 1) HE training (n=10), NHE training (n=10),
38 or no training (CON) (n=10). BFLH fascicle length was assessed before, during (Week 5) and
39 after the intervention with 2D-ultrasound. Hamstring muscle size was determined before and
40 after training via magnetic resonance imaging.
Nossos dados sugerem que um macrociclo com ênfase na capacidade técnica e tática foi capaz de promover aumentos no desempenho físico e tático de jovens jogadores de futebol em situações reais de disputa. Assim, a distribuição das cargas de treinamento utilizadas neste estudo, além de possibilitar uma formação mais específica e contextual, proporcionou um aumento da intensidade do jogo no final da temporada, variável diretamente relacionada ao resultado do jogo (17). Além disso, verificou-se que o protocolo de treinamento causou reduções nos marcadores de danos musculares, revelando um estímulo benéfico para o sistema muscular, o que pode contribuir para a prevenção de lesões por sobreentrenamento ao longo da temporada. Apesar da importância bem documentada da avaliação de parâmetros sangüíneos (ie, marcadores de dano) durante a prática de futebol (3, 4, 23, 29), verificamos que a redução relacionada foi associada com maior taxa de trabalho durante o jogo, Através de um treinamento técnico-tático de periodização, mostrando a importância do monitoramento desses parâmetros em longo prazo.
Short inter-set rest blunts resistance exercise-inducedFernando Farias
Manipulating the rest-recovery interval between sets of resistance exercise may influence
training-induced muscle remodelling. The aim of this study was to determine the acute muscle
anabolic response to resistance exercise performed with short or long inter-set rest intervals.
In a study with a parallel-group design, 16 males completed four sets of bilateral leg-press and
knee-extension exercise at 75% of one-repetition maximum to momentary muscular failure,
followed by ingestion of 25 g of whey protein. Resistance exercise sets were interspersed by
1 min (n = 8) or 5 min of passive rest (n = 8). Muscle biopsies were obtained at rest, 0, 4, 24
and 28 h postexercise during a primed continuous infusion of l-[ring-13C6]phenylalanine to
determine myofibrillar protein synthesis and intracellular signalling.
Postexercise Cold Water Immersion Benefits Are Not Greater than the Placebo E...Fernando Farias
A CWI placebo is also as effective as
CWI itself in the recovery of muscle strength over 48 h.
This can likely be attributed to improved subjective ratings
of pain and readiness for exercise, suggesting that the hy-
pothesized physiological benefits surrounding CWI may
be at least partly placebo related.
The effect of instability training on knee joint proprioception and core stre...Fernando Farias
A general 10-week IT program utilizing Swiss balls and body mass as a resistance proved effective for improving knee proprioception as well as trunk flexion and extension strength in previously inactive individuals. The present study demonstrates that the use of body weight as a resis- tance under unstable conditions can provide significant improvements in knee proprioception (for as long as 9 months after training) and trunk strength for the untrained population that should contribute to general health and functionality.
Eccentric training using external loads greater than the
relative concentric training intensity is a potent stimulus for
enhancements in muscle mechanical function, and MTU
morphological and architectural adaptations. The inclusion
of eccentric loads above maximal concentric strength is
therefore an avenue to induce novel training stimuli and
effect change in key determinants, and functional metrics,
of strength, power and speed performance. Strength
improvements are largely mode-specific and arise from a
combination of neural, morphological and architectural
adaptations [8]. Increased agonist volitional drive is posited
as the primary contributing factor to the marked increases
in eccentric strength observed following training [54].
Eccentric training improves concentric muscle power and
SSC performance to a greater extent than concentric or
traditional modalities
Effects of seated and standing cold water immersion on recovery from repeated...Fernando Farias
There were
no significant group differences between control and either of the cold water immersion interventions. Seated cold water
immersion was associated with lower DOMS than standing cold water immersion (effect size = 1.86; P = 0.001). These
data suggest that increasing hydrostatic pressure by standing in cold water does not provide an additional recovery benefit
over seated cold water immersion, and that both seated and standing immersions have no benefit in promoting recovery
John Orchard
Adjunct Associate Professor, Sydney Medical School, University of Sydney.
-
Hamstrings are most susceptible to injury during the late stance phase of sprinting
Training Load and Fatigue Marker Associations with Injury and IllnessFernando Farias
This paper provides a comprehensive review of the litera-
ture that has reported the monitoring of longitudinal
training load and fatigue and its relationship with injury
and illness. The current findings highlight disparity in the
terms used to define training load, fatigue, injury and ill-
ness, as well as a lack of investigation of fatigue and
training load interactions. Key stages of training and
competition where the athlete is at an increased risk of
injury/illness risk were identified. These included periods
of training load intensification, accumulation of training
load and acute change in load. Modifying training load
during these periods may help reduce the potential for
injury and illness.
Hamstring injuries are among the most com-
mon non-contact injuries in sports. The Nordic hamstring
(NH) exercise has been shown to decrease risk by
increasing eccentric hamstring strength.
Cold water immersion versus whole body cryotherapyFernando Farias
Cold-water immersion was more effective in
accelerating recovery kinetics than whole-body cryotherapy for countermovement jump
performance at 72h post-exercise. Cold-water immersion also demonstrated lower soreness
and higher perceived recovery levels across 24-48h post-exercise.
The effects of self-myofascial release using a foam roll or roller massager on joint range of motion, muscle recovery, and performance: a systematic review
Effects of Velocity Loss During Resistance Training on Performance in Profess...Fernando Farias
To analyze the effects of two resistance training (RT) programs that used the same relative loading but different repetition volume, using the velocity loss during the set as the independent variable: 15% (VL15) vs. 30% (VL30). Methods: Sixteen professional soccer players with RT experience (age 23.8 ± 3.5 years, body mass 75.5 ± 8.6 kg) were randomly assigned to two groups: VL15 (n = 8) or VL30 (n = 8) that followed a 6-week (18 sessions) velocity-based squat training program. Repetition velocity was monitored in all sessions. Assessments performed before (Pre) and after training (Post) included: estimated one- repetition maximum (1RM) and change in average mean propulsive velocity (AMPV) against absolute loads common to Pre and Post tests; countermovement jump (CMJ); 30-m sprint (T30); and Yo-yo intermittent recovery test (YYIRT).
High chronic training loads and exposure to bouts of maximal velocity running...Fernando Farias
The ability to produce high speeds is considered an important
quality for performance, with athletes shown to achieve 85–94% of
maximal velocity during team sport match-play.3 Well-developed
high-speed running ability and maximal velocity are required of
players during competition in order to beat opposition players
to possession and gain an advantage in attacking and defensive
situations.
EFFECTS OF STRENGTH TRAINING ON SQUAT AND SPRINT PERFORMANCE IN SOCCER PLAYERSFernando Farias
We have demonstrated that a simple in-season strength training program resulted in an improvement in maximal back squat performance, which was reflected in improve- ments in short sprint performance, as identified by a decrease in sprint time over 5, 10, and 20 m, in professional soccer players, in line with the hypotheses. Furthermore, the changes in relative 1RM squat strength demonstrate strong associations with the changes in 5 (r = 0.62), 10 (r = 0.78), and 20-m (r = 0.60) sprint performances.
Sprint running acceleration is a key feature of physical performance in team sports, and recent
literature shows that the ability to generate large magnitudes of horizontal ground reaction force
and mechanical effectiveness of force application are paramount. We tested the hypothesis that
very-heavy loaded sled sprint training would induce an improvement in horizontal force
production, via an increased effectiveness of application. Training-induced changes in sprint
performance and mechanical outputs were computed using a field method based on velocity-
time data, before and after an 8-week protocol (16 sessions of 10x20-m sprints). 16 male
amateur soccer players were assigned to either a very-heavy sled (80% body-mass sled load)
or a control group (unresisted sprints). The main outcome of this pilot study is that very-heavy
sled resisted sprint training, using much greater loads than traditionally recommended, clearly
increased maximal horizontal force production compared to standard unloaded sprint training
(effect size of 0.80 vs 0.20 for controls, unclear between-group difference) and mechanical
effectiveness (i.e. more horizontally applied force; effect size of 0.95 vs -0.11, moderate
between-group difference)
To examine the acute effects of generic (Running Drills, RD) and specific (Small-
Sided Games, SSG) Long Sprint Ability (LSA) drills on internal and external load of male
soccer-players. Methods: Fourteen academy-level soccer-players (mean±SD; age 17.6±0.61
years, height 1.81±0.63 m, body-mass 69.53±4.65 kg) performed four 30s LSA bouts for
maintenance (work:rest, 1:2) and production (1:5) with RD and SSG drills. Players’ external-
load was tracked with GPS technology (20Hz) and heart-rate (HR), blood-lactate
concentrations (BLc) and rate of perceived exertion (RPE) were used to characterize players’
internal-load. Individual peak BLc was assessed with a 30s all-out test on a non-motorized
treadmill (NMT). Results: Compared to SSGs the RDs had a greater effect on external-load
and BLc (large and small, respectively). During SSGs players covered more distance with
high-intensity decelerations (moderate-to-small). Muscular-RPE was higher (small-to-large)
in RD than in SSG. The production mode exerted a moderate effect on BLc while the
maintenance condition elicited higher cardiovascular effects (small-to-large). Conclusion:
The results of this study showed the superiority of generic over specific drills in inducing
LSA related physiological responses. In this regard production RD showed the higher post-
exercise BLc. Interestingly, individual peak blood-lactate responses were found after the
NMT 30s all-out test, suggesting this drill as a valid option to RD bouts. The practical
physiological diversity among the generic and specific LSA drills here considered, enable
fitness trainers to modulate prescription of RD and SSG drills for LSA according to training
schedule.
Bilateral and unilateral vertical ground reaction forcesFernando Farias
The purposes of this study were to assess unilateral and bilateral vertical jump performance
characteristics, and to compare the vertical ground reaction force characteristics of the impulse and landing
phase of a vertical jump between the dominant and non-dominant leg in soccer players.
Impact of the Nordic hamstring and hip extension exercises on hamstring archi...Fernando Farias
The architectural and morphological adaptations of the hamstrings in response to training
33 with different exercises have not been explored. PURPOSE: To evaluate changes in biceps
34 femoris long head (BFLH) fascicle length and hamstring muscle size following 10-weeks of
35 Nordic hamstring exercise (NHE) or hip extension (HE) training. METHODS: Thirty
36 recreationally active male athletes (age, 22.0 ± 3.6 years, height, 180.4 ± 7 cm, weight, 80.8 ±
37 11.1 kg) were allocated to one of three groups: 1) HE training (n=10), NHE training (n=10),
38 or no training (CON) (n=10). BFLH fascicle length was assessed before, during (Week 5) and
39 after the intervention with 2D-ultrasound. Hamstring muscle size was determined before and
40 after training via magnetic resonance imaging.
Nossos dados sugerem que um macrociclo com ênfase na capacidade técnica e tática foi capaz de promover aumentos no desempenho físico e tático de jovens jogadores de futebol em situações reais de disputa. Assim, a distribuição das cargas de treinamento utilizadas neste estudo, além de possibilitar uma formação mais específica e contextual, proporcionou um aumento da intensidade do jogo no final da temporada, variável diretamente relacionada ao resultado do jogo (17). Além disso, verificou-se que o protocolo de treinamento causou reduções nos marcadores de danos musculares, revelando um estímulo benéfico para o sistema muscular, o que pode contribuir para a prevenção de lesões por sobreentrenamento ao longo da temporada. Apesar da importância bem documentada da avaliação de parâmetros sangüíneos (ie, marcadores de dano) durante a prática de futebol (3, 4, 23, 29), verificamos que a redução relacionada foi associada com maior taxa de trabalho durante o jogo, Através de um treinamento técnico-tático de periodização, mostrando a importância do monitoramento desses parâmetros em longo prazo.
Short inter-set rest blunts resistance exercise-inducedFernando Farias
Manipulating the rest-recovery interval between sets of resistance exercise may influence
training-induced muscle remodelling. The aim of this study was to determine the acute muscle
anabolic response to resistance exercise performed with short or long inter-set rest intervals.
In a study with a parallel-group design, 16 males completed four sets of bilateral leg-press and
knee-extension exercise at 75% of one-repetition maximum to momentary muscular failure,
followed by ingestion of 25 g of whey protein. Resistance exercise sets were interspersed by
1 min (n = 8) or 5 min of passive rest (n = 8). Muscle biopsies were obtained at rest, 0, 4, 24
and 28 h postexercise during a primed continuous infusion of l-[ring-13C6]phenylalanine to
determine myofibrillar protein synthesis and intracellular signalling.
Postexercise Cold Water Immersion Benefits Are Not Greater than the Placebo E...Fernando Farias
A CWI placebo is also as effective as
CWI itself in the recovery of muscle strength over 48 h.
This can likely be attributed to improved subjective ratings
of pain and readiness for exercise, suggesting that the hy-
pothesized physiological benefits surrounding CWI may
be at least partly placebo related.
The effect of instability training on knee joint proprioception and core stre...Fernando Farias
A general 10-week IT program utilizing Swiss balls and body mass as a resistance proved effective for improving knee proprioception as well as trunk flexion and extension strength in previously inactive individuals. The present study demonstrates that the use of body weight as a resis- tance under unstable conditions can provide significant improvements in knee proprioception (for as long as 9 months after training) and trunk strength for the untrained population that should contribute to general health and functionality.
Eccentric training using external loads greater than the
relative concentric training intensity is a potent stimulus for
enhancements in muscle mechanical function, and MTU
morphological and architectural adaptations. The inclusion
of eccentric loads above maximal concentric strength is
therefore an avenue to induce novel training stimuli and
effect change in key determinants, and functional metrics,
of strength, power and speed performance. Strength
improvements are largely mode-specific and arise from a
combination of neural, morphological and architectural
adaptations [8]. Increased agonist volitional drive is posited
as the primary contributing factor to the marked increases
in eccentric strength observed following training [54].
Eccentric training improves concentric muscle power and
SSC performance to a greater extent than concentric or
traditional modalities
Effects of seated and standing cold water immersion on recovery from repeated...Fernando Farias
There were
no significant group differences between control and either of the cold water immersion interventions. Seated cold water
immersion was associated with lower DOMS than standing cold water immersion (effect size = 1.86; P = 0.001). These
data suggest that increasing hydrostatic pressure by standing in cold water does not provide an additional recovery benefit
over seated cold water immersion, and that both seated and standing immersions have no benefit in promoting recovery
John Orchard
Adjunct Associate Professor, Sydney Medical School, University of Sydney.
-
Hamstrings are most susceptible to injury during the late stance phase of sprinting
Training Load and Fatigue Marker Associations with Injury and IllnessFernando Farias
This paper provides a comprehensive review of the litera-
ture that has reported the monitoring of longitudinal
training load and fatigue and its relationship with injury
and illness. The current findings highlight disparity in the
terms used to define training load, fatigue, injury and ill-
ness, as well as a lack of investigation of fatigue and
training load interactions. Key stages of training and
competition where the athlete is at an increased risk of
injury/illness risk were identified. These included periods
of training load intensification, accumulation of training
load and acute change in load. Modifying training load
during these periods may help reduce the potential for
injury and illness.
Hamstring injuries are among the most com-
mon non-contact injuries in sports. The Nordic hamstring
(NH) exercise has been shown to decrease risk by
increasing eccentric hamstring strength.
Cold water immersion versus whole body cryotherapyFernando Farias
Cold-water immersion was more effective in
accelerating recovery kinetics than whole-body cryotherapy for countermovement jump
performance at 72h post-exercise. Cold-water immersion also demonstrated lower soreness
and higher perceived recovery levels across 24-48h post-exercise.
Nikos Malliaropoulos - Rehabilitation of hamstring injuries MuscleTech Network
Nikos Malliaropoulos
Director of the Athletics National Sports Medicine Centre Thessaloniki Greece. Consultant SEM Physician Barts and The London Clinical Senior Lecturer QMUL CSEM.
-
The rehabilitation of Hamstring injuries - Can we be more injury specific?
(6th MuscleTech Network Workshop)
14th October, Barcelona
Effects of a six week hip thrust versus front squatFernando Farias
Hip thrust training resulted in greater improvements in the isometric mid-thigh pull peak
force compared to squat training, even though the pull involved a vertical force vector. It is
proposed that this is due to the hip extension moment-angle curves of the squat versus that of the
hip thrust, in that the hip thrust likely has a greater hip extension moment requisite at the angle at
which the isometric mid-thigh pull is performed, but these joint-specific kinetic hypotheses
require further investigation.
An experimental study on scapulothoracic and glenohumeral kinematics followin...pharmaindexing
Aim
This study aimed to find out the effect of rotator cuff fatigue on humeral head migration during dynamic shoulder external rotation activity (combination of flexion, abduction, external rotation) in tennis players.
Objectives
The purpose for physiotherapist in sports performance enhancement assessment of shoulder kinematics provides a reliable tool for studying kinematics during arm elevation.
To understand the importance of external rotation strengthening on clearing superior glenohumeral joint migration for tennis professionals.
Materials and Methods
A total of 20 men of tennis players without shoulder disorders were recruited in the study. The study was conducted in the Tamilnadu tennis association (TNTA) and Gandhi nagar tennis club (GNC adayar). Pre and post tests were performed.
Results
The data was analyzed using SPSS. The experimental group (who received external rotator fatigue protocol) showed significance with (p=0.001) value when compared with the control group. Also, the post-test mean value of the experimental group showed a significant improvement after the protocol.
Conclusion
External rotators stretching and strengthening protocol showed significant improvement in functional status of glenohumeral joint than conventional traditional coaching program alone on tennis professionals.
A universalidade das Regras do Jogo significa que o jogo é essencialmente o
mesmo em todas as partes do mundo e em todos os níveis. Bem como promover um
ambiente justo e seguro para a sua prática, as Regras também devem promover a
participação e a diversão.
O jogo deve ser jogado e arbitrado da mesma maneira em todos os campos de
futebol pelo mundo, desde a final da Copa do Mundo FIFA™ até um jogo em um
vilarejo remoto. No entanto, as características locais de cada país devem determinar
a duração da partida, quantas pessoas podem participar e como algumas atitudes
inapropriadas devem ser punidas.
A evidência apresentada sugere que a variação é um componente necessário do planejamento efetivo do treinamento. Apoiando essa perspectiva, outras pesquisas sugerem que a monotonia de treinamento elevado - que pode ser amplamente percebida como uma falta de variação20 - leva a uma maior incidência de síndromes de overtraining21, um mau desempenho e freqüência de infecções banais.22 Inversamente, as reduções na monotonia têm Tem sido associada a uma maior incidência de melhor desempenho pessoal 22, e os índices de monotonia têm sido defendidos como ferramentas benéficas de treinamento-regulação na elite rowing23 e no sprint24.
Capacidade manter as ações de jogo em alto
padrão de execução durante 90 minutos. É
muito importante no segundo tempo que é
onde ocorre o maior número de gols e
normalmente se decidem as partidas.
A literatura atual que mede os efeitos de SMR ainda está emergindo. Os resultados desta análise sugerem que o rolamento de espuma e a massagem com rolo podem ser intervenções eficazes para melhorar a ROM conjunta e o desempenho muscular pré e pós-exercício. No entanto, devido à heterogeneidade dos métodos entre os estudos, atualmente não há consenso sobre o ótimo programa SMR.
Actualmente la capacidad de repetir sprints es considerada fundamental en el rendimiento del fútbol por
parecerse al patrón de movimiento que se da en el mismo. De esta manera su entrenamiento resulta fundamental
en cualquier planificación. Así, se deben trabajar aquellos aspectos que la limitan para poder acceder a un mayor
rendimiento. Una vez conocido esto se debería elegir la forma en la que se quiere entrenar, teniendo para ello
métodos analíticos (interválico, intermitente) y contextualizados (espacios reducidos). Por último, se proponen
una series de variables de entrenamiento para el trabajo de repetir sprints, orientándolo no solo al aspecto físico,
sino también al técnico, táctico y psicológico, conformando, por tanto, un entrenamiento integrado en el fútbol.
Maximal sprinting speed of elite soccer playersFernando Farias
Current findings might help individuals involved within the physical preparation of players (e.g. technical coaches, fitness coaches, and sport science staff) when developing training programs and training sessions in line with the playing positions, and with the levels of high speed running targeted to reach during specific training drills like sided-games.
Indeed, the closer to match-play situations regarding the rules with goals, goalkeepers, the larger pitch sizes and greater number of players involved, the higher sprinting speed running players would reach during sided-games. However, coaches are advised to add specific speed drills to sided-games in order to elicit a stimulus of high-speed running high enough to prepare players for competition.
Recovery in Soccer Part I – Post-Match Fatigue and Time Course of RecoveryFernando Farias
In elite soccer, players are frequently required to play consecutive matches
interspersed by 3 days and complete physical performance recovery may not
be achieved. Incomplete recovery might result in underperformance and in-
jury. During congested schedules, recovery strategies are therefore required
to alleviate post-match fatigue, regain performance faster and reduce the risk
of injury. This article is Part I of a subsequent companion review and deals
with post-match fatigue mechanisms and recovery kinetics of physical per-
formance (sprints, jumps, maximal strength and technical skills), cognitive,
subjective and biochemical markers.
Hip extension and Nordic hamstring exercise training both promote the elongation of
biceps femoris long head fascicles, and stimulate improvements in eccentric knee
flexor strength.
Hip extension training promotes more hypertrophy in the biceps femoris long head
and semimembranosus than the Nordic hamstring exercise, which preferentially
develops the semitendinosus and the short head of biceps femoris
No sentido de melhor esclarecer esta forma de operacionalizar o processo
de treino procuramos num primeiro momento sistematizar os aspectos
conceptometodológicos que a definem. Contudo, a “Periodização Táctica”
é uma concepção que se encontra pouco retratada na literatura e por isso,
deparamo-nos com escassas referências bibliográficas levando-nos a
reequacionar o teor deste trabalho. Neste seguimento, decidimos incidir
nos fundamentos conceptometodológicos que a definem, a partir de dados
empíricos do processo de treino-competição do treinador José Guilherme
Oliveira
. A escolha deste treinador deve-se ao facto de ser reconhecido pelo
professor Vítor Frade como um dos treinadores que operacionaliza o processo
de treino tendo em conta as premissas da “Periodização Táctica”.
Acute cardiopulmonary and metabolic responses to high intensity interval trai...Fernando Farias
Results from the present study quantify the effects of altering either the intensity of the
work or the recovery interval when performing interval sessions consisting of 60s of work and
60s of recovery for multiple repetitions. The information provided may aid those interested in
designing interval training sessions by providing ranges of values that could be expected for
individuals who possess moderate levels of cardiopulmonary fitness. Using a work intensity of
80% or 100% VGO2peak and a recovery intensity of 0% or 50% VGO2peak, subjects were able to
exercise within the ACSM recommended range for exercise intensity. Based upon the data it
would appear that a protocol such as the 80/0 may be appropriate for those individuals who
are just beginning a program or have little experience with interval-type activity. By contrast, a
100/50 protocol could not be completed by all of the subjects and therefore may be too intense
for some individuals.
The quadriceps femoris is traditionally described as a muscle group com-
posed of the rectus femoris and the three vasti. However, clinical experience
and investigations of anatomical specimens are not consistent with the text-
book description. We have found a second tensor-like muscle between the
vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the
tensor VI (TVI). The aim of this study was to clarify whether this intervening
muscle was a variation of the VL or the VI, or a separate head of the exten-
sor apparatus. Twenty-six cadaveric lower limbs were investigated...
Hamstring strain prevention in elite soccer playersFernando Farias
Hamstring strains are among the most
common injury in sport and are most
often observed in sports that involve
sprinting, turning, and jumping
(8,38,63). The prevalence of hamstring
strains has been measured between 11
and 16% in studies of soccer, Australian
rules football, and cricket (92). This can
result in an average of 6 players per squad
suffering a hamstring injury (defined as
“preventing player participation in
a match”) each season in professional
soccer and Australian rules football
Euro Cup international supporters can book Euro 2024 Tickets from our online platform Worldwideticketsandhospitality.com. Followers can book Turkey Vs Portugal Tickets on our website at sale prices.
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Ukraine Euro Cup 2024 Squad Sergiy Rebrov's Selections and Prospects.docxEuro Cup 2024 Tickets
After securing their spot through the playoff route, Ukraine is gearing up for their fourth consecutive European Championship. Ukraine first qualified as hosts in 2012, but in 2016
Results for LtCol Thomas Jasper, Marine, for the 2010 Marine Corps Marathon held October 31, 2010, marking the 35th annual marathon known as "The People's Marathon."
An impressive finishing time of 3:46:39, placing 324th in the Male division ages 40-44.
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Akshay Ram on Adobe's Creative Strategy and Execution, the Present and Future...Neil Horowitz
On episode 271 of the Digital and Social Media Sports Podcast, Neil chatted with Akshay Ram, Product Manager for Adobe, who also has a lot of knowledge and insight into sports creative.
What follows is a collection of snippets from the podcast. To hear the full interview and more, check out the podcast on all podcast platforms and at www.dsmsports.net
Euro Cup fans worldwide can book Euro 2024 Tickets from our online platform www.worldwideticketsandhospitality. Fans can book Ukraine Vs Belgium Tickets on our website at discounted prices.
Mats André Zuccarello Aasen, commonly known as Mats Zuccarello, was born on September 1, 1987, in
Oslo, Norway. He grew up in the bustling neighborhood of Løren, where his passion for ice hockey began
at a young age. His mother, Anita Zuccarello, is of Italian descent, and his father, Glenn Aasen, is
Norwegian. This multicultural background played a significant role in shaping his identity and versatility
on and off the ice.
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Mock 2024 NHL Draft Experts Divided after Celebrini, Levshunov, Silayev go in...Ice Brek
After the NHL Draft Lottery on Monday, Adam Kimelman, NHL.com’s deputy managing editor,
and Mike G., senior draft writer, Morreale make their predictions for how the first 16 selections
of the 2024 Upper Deck NHL Draft could turn out.
Albania vs Spain Euro Cup 2024 Very Close Armando Broja Optimistic Albania Wi...Eticketing.co
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2. Hamstring Resistance Training 85
injuries,5 and represent approximately 4.8% of all athletic injuries.6,7 The ham-
strings relationship to the ACL has been demonstrated in a variety of studies.
According to More et al,8 in-vitro assessment of a cadaveric model revealed that
the hamstring acts as an ACL synergist decreasing the anterior translation of the
tibia as well as reducing internal tibial rotation during a simulated squat. Others
have reported that hamstring activation stabilizes the ACL deficient knee, aids
ligaments in maintaining joint stability, equalizes articular surface pressure
distribution,8 and regulates the joints’ mechanical impedance.3,9
Training the quadriceps disproportionately to the hamstrings may inhibit
hamstring coactivation, reduce joint stability, and increase anterior tibial transla-
tion in response to strong quadriceps forces.10,11 Fortunately, hamstring training
reduces hamstring inhibition, hamstring-to-quadriceps imbalance, bilateral ham-
string deficits, and the risk of reinjury for those who had previous hamstring
strains.3,12 Hamstring resistance training reduces magnitude of the hamstring-to-
quadriceps muscle imbalance, which may prevent muscle strains13,14 and ACL
injuries.3,12 Resistance training exercises offering higher hamstring activation are
believed to be optimal for hamstring strength development and rehabilitation of
those with ACL problems and should include closed–kinetic chain (CKC)
exercises.15,16 Unfortunately, evidence is limited with respect to optimal resistance
training exercises for activating the hamstrings.
In an attempt to quantify the role of the hamstring during resistance training,
researchers have used electromyography (EMG) to examine muscle activation
during variations of the dead lift,17 squat and leg press,18 squat with varying loads,
and variations in squat technique.19–22,24 In the most comprehensive assessment of
hamstring activation to date, Wright et al23 demonstrated that the leg curl and stiff
leg dead lift were superior to the back squat.
At present, information is limited regarding which resistance training exer-
cises maximally activate the hamstrings, the resultant hamstring-to-quadriceps
activation ratios, and if gender differences exist despite the fact that training the
hamstring muscle group is critical for performance and may play an important
role in hamstring and ACL injury prevention. Therefore, the primary purpose of
this study was to assess a variety of resistance training exercises to quantify ham-
string activation. This study also sought to assess the activation of the rectus femo-
ris to determine biarticular quadriceps muscle function and to determine a mea-
sure of activation ratios between the muscles assessed during these exercises, as
well as to determine if there are gender differences in these variables. Quantifica-
tion of these resistance training exercises is necessary to provide clinicians with
information about the optimal exercises for hamstring strengthening and rehabili-
tation programs for hamstring and ACL injuries.
Methods
Subjects
Thirty-four subjects including 21 men and 13 women NCAA Division-I or
Division-III athletes (20.38 ± 1.77 years) volunteered for this study. Subject
3. 86 Ebben
characteristics are presented in Table 1. All subjects provided written informed
consent for this study, which was approved by the university’s internal review
board.
Research Design
This study used a randomized repeated measures research design to compare
EMG activation of the hamstring muscle group (H) and the rectus femoris (Q)
during six resistance training exercises. The research hypothesis was that there
were differences in H and Q activation between the exercises studied and that men
and women would manifest different H-to-Q activation ratios characterized by Q
dominance for women. Independent variables included the resistance training
exercise assessed and gender. Dependent variables included the root mean square
(RMS) EMG of the H and Q as well as for the H-to-Q ratio, all expressed as a
percentage of the RMS EMG of the MVIC, for each of the exercises evaluated, as
well as gender differences in these variables. Data were also analyzed for squat
strength matched men and women.
Methodology
Before a pretest orientation and the primary testing session, subjects participated
in a general and dynamic warm-up, consistent with the methods previously used.19
All subjects were familiarized with the test procedures during the pretest orienta-
tion, including performing an MVIC at 60° of knee flexion for the H and Q, with
selectorized seated leg curl (Hammer Strength, Schiller Park, IL, USA) and leg
extension (Magnum Fitness Systems, South Milwaukee, WI, USA) machines
respectively, loaded with an immovable mass. In addition, each subject’s 6-repe-
tition maximum (RM) was assessed for the randomly ordered test exercises,
including the squat, seated leg curl, stiff leg dead lift, single leg stiff leg dead lift,
good morning, and the Russian curl. The exercises selected are frequently used
and are commonly believed to be effective at training the hamstrings. The squat
wasincludedbecauseitiswaspreviouslycomparedwithtwohamstringexercises,23
and serves as a useful reference for hamstring-to-quadriceps activation ratio under
Table 1 Subject Characteristics
Variable All Subjects Women (N = 13) Men (N = 21)
Age (y) 20.38 ± 1.78 20 ± 0.70 20.61 ± 0.71
Age range (y) 18–26 19–21 18–26
Weight (kg) 77.94 ± 18.30 63.64 ± 18.30 86.80 ± 17.90
Weight range (kg) 54.55–133.64 54.55–72.73 65.90–133.64
Training (days/week) 4.15 ± 1.79 4.00 ± 1.77 4.24 ± 1.84
Squat 6 RM (kg) 101.47 ± 34.08 68.18 ± 12.31 122.07 ± 25.65
Squat 6RM range (kg) 52.27–184.09 52.27–88.64 84.09–184.09
Values are mean ± SD.
4. Hamstring Resistance Training 87
conditions where the quadriceps are typically dominant. Six RMs were chosen
because assessment of muscular strength, as opposed to endurance, was desired.
After approximately 72 hours, during which no resistance training was performed,
subjects returned for the primary testing session. Each subject performed a MVIC
for the H and Q for 5 seconds. Subjects then performed 2 full range-of-motion
repetitions, at maximal volitional velocity, using their 6-RM loads, for each of the
randomly ordered test exercises. Limiting the test to two repetitions per exercise,
randomization of the exercise order, and 5 minutes of recovery were provided
between the MVICs as well as all exercises, to reduce order and fatigue effects.
The technique for each exercise is described as follows.
Squat Methods
Subjects performed the squat using a closed pronated grip, slightly wider than
shoulder width apart, with the barbell positioned at the base of the neck, the scap-
ula retracted and the cervical spine slightly hyperextended. The feet were slightly
abducted and positioned flat on the floor in a bilateral stance slightly wider than
shoulder width. Subjects descended by flexing the hips and knees until the bottom
of the thighs were parallel to the floor, while keeping a constant floor-to-torso
angle, normal lordotic arch, scapula retracted, and knees aligned over the feet.
Subjects ascended using similar form.
Seated Leg Curl Methods
Subjects performed the seated leg curl while seated leg in a leg curl machine with
their legs positioned parallel to each other and with their back firmly against the
seat back and secured to the seat using the machines belt. The subjects’ knees
were aligned with the axis of the machine, and ankles were placed on top of the
roller pad, with the exercise beginning is a position of knee extension. Subjects
flexed the knees moving the machine through its full range of motion, while grip-
ping on the machine’s handgrips and keeping the buttocks and back in contact
with the machine’s seat and seat back. Subjects then allowed their knees to extend
to return to the starting position. The subjects’ ankles were maintained in a neutral
position throughout the range of motion of the exercise.
Stiff Leg Dead Lift Methods
Subjects performed the stiff leg dead lift by holding the barbell with an approxi-
mately shoulder-width grip, with extended elbows and arms in an anatomically
correct position with the exception of using a closed pronated grip. The feet were
placed flat on the floor in a hip-width stance with the knees slightly flexed to
approximately 15° and toes pointed straight ahead. Subjects then flexed the hips
allowing the torso and barbell to lower to a point where the weight plates lightly
touched the floor. Subjects then extended their hips and torso returning to an
upright position. Through the entire range of motion of the exercise, the subjects
maintained approximately 15° of knee flexion, their normal lordotic arch, retracted
scapula, and a slightly extended cervical spine.
5. 88 Ebben
Single Leg Stiff Leg Dead Lift Methods
Subjects performed the single leg stiff leg dead lift by standing erect holding two
dumbbells at their side using a semisupinated grip with extended elbow. Subjects
stood on their right leg only with the knee slightly flexed to approximately 15° and
toes pointed straight ahead. The subjects left knee was flexed to approximately
45° and at no time made contact with the floor. Subjects then flexed the hips of the
right leg allowing the torso and dumbbells to lower to a point where the dumbbells
lightly touch the floor. Subjects then extended their hip and torso returning to an
upright position. Subjects were instructed to avoid abduction and adduction of the
right hip during the performance of the exercise. Through the entire range of
motion of the exercise, the subjects maintained slight knee flexion, their normal
lordotic arch, retracted scapula, and a slightly extended cervical spine.
Good Morning Methods
During the performance of the good morning, subjects gripped the barbell with a
closed pronated grip slightly wider than shoulder width and positioned the barbell
at the base of the neck, the scapula retracted, and the cervical spine slightly hyper-
extended. The feet were positioned flat on the floor in a bilateral stance of shoul-
der width with the toes pointed forward. Subjects then flexed the hips, while main-
taining constant knee flexion of approximately 15°, allowing the torso and barbell
to lower to point where the torso was parallel to the floor. Subjects then extended
their hips and torso returning to an upright position. Through the entire range of
motion of the exercise, the subjects maintained limited knee flexion, their normal
lordotic arch, retracted scapula, and a slightly extended cervical spine.
Russian Curl Methods
Subjects began the Russian curl exercise in a kneeling position on a “glute-ham”
machine, with the knees positioned 4 cm posterior of the apex of the machine’s
pad. The ankles were secured between the machine’s foot pads. At the beginning
of the exercise the subjects’ knees were flexed at approximately 90° while the hips
were extended in the anatomically correct position. This hip position was main-
tained throughout the exercise. Subjects held their exercise load, in the form of a
weight plate, in their hands, which were placed in a crossed-arm position touching
their chest. Subjects extended their knees lowering their torso until they were
nearly parallel to the ground, while maintaining an anatomically correct hip posi-
tion, normal lordotic arch, and a neutral cervical spine. Subjects then flexed the
knee, thus moving back to the starting position.
Electromyography
Electromyography was used to quantify muscle activity using a two-channel,
fixed shielded cabled, Delsys Bagnoli-2 EMG system (Delsys Inc. Boston, MA,
USA). The input impedance was 1015 Ω and the common mode rejection ratio was
>80 dB. Electroymyographic data from the H and Q were recorded at 1024 Hz
using rectangular shaped (19.8 mm wide and 35 mm long) bipolar surface elec-
trodes with 1 × 10 mm 99.9% Ag conductors, and an interelectrode distance of 10
6. Hamstring Resistance Training 89
mm. Electrodes were placed on the longitudinal axis of the muscles with the H
electrode located halfway between the gluteal fold and the popliteal fossa. The Q
electrode was placed halfway between the greater trochanter and medial epicon-
dyle of the femur. A common reference electrode was placed 10 mm anterior and
halfway between the medial condyle and medial malleolus of the tibia. Electrode
placement was chosen to assess biarticular knee flexor and extensor muscles simi-
lar to methods previously used in studies that compared variations of closed and
open–kinetic chain exercises.19,25 Furthermore, quantification of hamstring activa-
tion has frequently been studied using one electrode on either the belly or biceps
femoris.3,15,22,25,26 Skin preparation included shaving hair, abrading, and cleaning
the surface with alcohol. Elastic tape was applied to ensure electrode and cable
placement, and provide cable strain relief. Surface electrodes were connected to
an amplifier and streamed continuously through an analog-to-digital converter
(Delsys Inc.) to an IBM-compatible notebook computer. All data were filtered
with a bandpass filter allowing 10 Hz high pass and 450 Hz low pass, saved, and
analyzed with the use of computer software (EMGworks 3.1, Delsys Inc.). Root
mean square EMG signal processing was calculated over a 125-ms moving
window and used on all EMG data for the duration of the exercise and normalized
to the RMS EMG signal of the MVIC to determine H and Q activation, H-to-Q
activation ratios, performance between genders, and to evaluate results with
respect to previous research. Data were analyzed for the second repetition of each
exercise and compared with the MVIC of each muscle group. Data for the MVIC
were analyzed for the 3rd to 4th second of the 5-second muscle action.
Statistical Analyses
Data were analyzed with SPSS 16.0 for Windows (Microsoft Corporation, Red-
mond, WA, USA) using a repeated-measures ANOVA with Bonferroni adjusted
pairwise comparisons of significant findings. Independent samples t tests were
conducted to determine differences in strength, age, training frequency, and ham-
string-to-quadriceps ratios between genders as well as strength-matched men and
women. Assumptions for linearity of statistics were tested and met. Statistical
effect size (d) and power (2) are reported, and all data are expressed as means ±
SD. The a priori alpha level was set at P < .05.
Results
Results reveal no significant interaction between gender and exercise type, F(5,
33) = 0.355, p = 0.88, d = 0.14, 2 = 0.01. Thus, the muscle activation in response
to these exercises is not different between men and women. Significant main
effects for exercise type were found for the H, F(5, 33) = 65.04, p = 0.00, d = 1.00,
2 = 0.66, as well as for the Q, F(5, 33) = 69.94, p = 0.00, d = 1.00, 2= 0.697,
RMS EMG normalized as a percentage of the RMS EMG of the MVIC, demon-
strating that a number of these exercises result in different degrees of activation of
the H and Q. Specific difference between exercises are described in Tables 2 and
3.
In addition, significant main effects were found for the H-to-Q activation
ratio when analyzed for all subjects, F(5, 33) = 21.26, p = 0.00, d = 1.00, 2 = 0.39,
9. 92 Ebben
indicating that these exercises produced different activation ratios (Table 4). Sepa-
rate analysis of the H-to-Q activation ratio was conducted for men, F(5, 20) =
46.77, p = 0.00, d = 1.00, 2 = 0.70, and women, F(5, 12) = 20.42, p = 0.00, d =
1.00, 2 = 0.63, as well as between and strength-matched men and women. Inde-
pendent samples t tests of these results revealed that women subjects achieved
lower H-to-Q ratios than men for a number of exercises (Table 5). Further analysis
of strength-matched men and women revealed that the H-to-Q ratios for women
were less than those for the men (Tables 6).
Finally, independent samples t tests demonstrated that there were significant
gender differences in squat strength (P < 0.001) and in squat strength-to-mass
ratio (P < 0.001), despite no significant difference in subject’s age (P = 0.33) or
training frequency (P = .71).
Discussion
This is the first study to assess measures of hamstring and quadriceps activation
and ratios, as well as gender differences, associated with a large variety of ham-
string resistance training exercises. Analysis of hamstring activation reveals that
for both genders, the Russian curl and leg curl exercises resulted in the greatest
hamstring activity. The stiff leg dead lift was superior to the squat and statistically
similar to the single leg stiff leg dead lift and the good morning. Similarities
between the good morning and stiff leg dead lift may be due to their biomechani-
cal similarities in range of motion at the knee and hip joints. The order of greatest
to least mean hamstring activation of each exercise was the same for both men and
women. Results of this study are consistent with those of Wright et al,23 who dem-
onstrated that the leg curl and stiff leg dead lift elicited more EMG activity than
the squat. Unlike the findings of Wright et al,23 the current study yielded signifi-
cant differences in EMG between the leg curl and stiff leg dead lift and evaluated
other exercises as well. Wright et al23 evaluated both eccentric and concentric
phases of the hamstring exercises. Even though an analysis of each these phases
of muscle action is instructive, the current study assessed hamstring EMG activity
for the entire resistance training movement because the exercises evaluated are
not typically performed exclusively in the eccentric or concentric phase.
Previous studies demonstrated no differences in hamstring muscle activation
between variations of the dead lift,17 the knee extension exercise, and leg press,26
or during compensatory resistance variations of the squat.19 Escamilla et al18 dem-
onstrated approximately 58 to 71% greater hamstring activity during the squat
than the leg press with variations in activation based on stance width. Specifically,
hamstring values during the squat ranging from approximately 31 to 41% of
MVIC. In the current study, the H attained 27% of the MVIC during the squat.
Thus the squat is not an optimal exercise for training the hamstrings.
Analysis of the Q activation indicated that for both men and women, the squat
resulted in predictably more Q activation than the seated leg curl, demonstrating
74% and 7% of the MVIC, respectively. This finding is consistent with previous
research that demonstrated Q activation of 6% of MVIC during the leg curl.9
Six-RM squat strength and squat strength normalized to body mass of women
were approximately 56 and 71% of the values attained by men, respectively
10. Hamstring Resistance Training 93
(p < 0.05). “Previous reports indicate that women are weaker than men, producing
approximately 50 and 54% of knee flexion and extension torque. Owing to the
large discrepancies, the gender discrepancies may remain even when normalized
to body mass.16,27 In the present study, women were 0.61 year younger than the
men and trained an average of 0.24 day less per week (4.00 vs. 4.24 days per
week). These measures of the training status of women were statistically similar
to those of the men, even though squat strength and squat strength-to-mass ratios
were significantly different.
The H-to-Q ratio was found to be considerably higher for open–kinetic chain
(OKC) exercises, such as the seated leg curl and Russian curl, than for ground-
based CKC exercises, such as the stiff leg dead lift, single leg stiff leg dead lift,
good morning, and squat, indicating that there is less quadriceps coactivation
during OKC and non-ground-based exercises. However, training with exercises
that include Q antagonism may also be useful for injury prevention since the H
and Q need to function together during a variety of athletic movement such as
jump landings28 during torsional stress associated with single leg support and cut-
ting.29 Therefore, exercises such as the stiff leg dead lift, single leg stiff leg dead
lift, and good morning may be useful to include in an exercise prescription.
When the H-to-Q ratio was analyzed with strength-matched men and women,
the gender disparity was more comprehensive. This result suggests that differ-
ences in these ratios are not attributable to differences in training status between
genders since strength matching of subjects included analysis of the strongest
women and weakest men. These findings are preliminary because the number of
subjects in this portion of the analysis is small. Gender differences in H-to-Q acti-
vation ratios were found in all of the exercises except the stiff leg dead lift and
squat, with women attaining approximately 54 to 89% of the male values. During
separate analysis of strength-matched women and men, gender difference in
H-to-Q ratio were found for all of the exercises, with women demonstrating only
36 to 76% of male values. These results confirm previous reports of gender differ-
ences in H-to-Q ratios with women attaining approximately 41 to 61% of ratios
typical of men, when assessed with isokinetic testing.30 The gender differences in
H-to-Q ratio associated with the strongest women demonstrate that athletic women
are also Q dominant during the performance of resistance training exercises, sup-
porting the general belief that women are Q dominant as demonstrated by isoki-
netic testing.31 In the current study, gender differences in H-to-Q ratios were
manifested during both OKC and CKC H exercise, during exercises that are not H
dominant such as the squat, and with strength matched subjects. Previous research
demonstrating gender differences in H-to-Q ratio was limited to isokinetic
testing.31
Practical Application
Hamstring training should be included in programs designed to increase leg
strength, reduce muscle imbalances, prevent H strains, and potentially reduce
ACL injuries. Results of this study help determine the H exercises that offer the
greatest muscle activation, such as the Russian curl and seated leg curl. Consider-
ation should also be given to including a number of H exercises for program varia-
12. Hamstring Resistance Training 95
tion, and to follow the principle of biomechanic specificity. Thus, CKC and
ground-based exercises, such as the stiff leg dead lift, single leg stiff leg dead lift,
and good mornings, should be included as well, in order to train athletes for sports
or activities that require H functioning during simultaneous Q activation. Whereas
these CKC exercise options have lower H-to-Q activation ratios compared with
the Russian curl and leg curl, these exercises still activate the H to a much greater
degree than the Q, and are not likely increase Q dominance in subjects who train
with them. Finally, women in this study had lower H-to-Q ratios, which were
present regardless of exercise type or subject strength. Thus, H training may be
particularly important for women.
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