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
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.
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.
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.
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
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
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.
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.
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.
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
Mechanics of the human hamstring muscles during sprintingFernando Farias
As peak musculotendon
force and strain for BF
LH
, ST, and SM occurred around the same time during terminal swing, it is suggested that this period in the
stride cycle may be when the biarticular hamstrings are at greatest injury risk. On this basis, hamstring injury prevention or rehabilitation
programs should preferentially target strengthening exercises that involve eccentric contractions performed with high loads at longer
musculotendon lengths.
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.
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.
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.
Transfer of strength and power training to sports performance Fernando Farias
The purposes of this review are to identify the factors that contribute to the
transference of strength and power training to sports performance and to pro-
vide resistance-training guidelines. Using sprinting performance as an example,
exercises involving bilateral contractions of the leg muscles resulting in vertical
movement, such as squats and jump squats, have minimal transfer to performance.
However, plyometric training, including unilateral exercises and horizontal
movement of the whole body, elicits signifi cant increases in sprint acceleration
performance, thus highlighting the importance of movement pattern and contrac-
tion velocity specifi city. Relatively large gains in power output in nonspecifi c
movements (intramuscular coordination) can be accompanied by small changes in
sprint performance. Research on neural adaptations to resistance training indicates
that intermuscular coordination is an important component in achieving transfer to
sports skills. Although the specifi city of resistance training is important, general
strength training is potentially useful for the purposes of increasing body mass,
decreasing the risk of soft-tissue injuries, and developing core stability. Hyper-
trophy and general power exercises can enhance sports performance, but optimal
transfer from training also requires a specifi c exercise program.
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.
Effects of Eccentric Strength Training’s Time on Daily Plasma Testosterone Le...IOSR Journals
This study aims to evaluate the effects of the eccentric physical training’s time on daily plasma concentrations of testosterone among sedentary athletes. Sixty male athletes, with homogeneous age, size and weight were selected for the study during three months. They were subjects to a strength training of the extensor and flexor muscles of the knee. After they were divided in two groups of thirty subjects and then had physical training either in the morning between 6 and 7, or in the evening, between 16 and 17. The dosage of testosterone on each athlete was performed before and after submission to an eccentric physical program at the antecubital vein in a restful sitting. Our results have shown that eccentric physical training induces the increase of this steroid hormone in the two groups of athletes and the training in the evening promotes better its production. Our results also showed that the rate of this androgen drop significantly during the day in both groups of athletes trained in the morning or in the evening as well as their respective controls. However, the decline was even more pronounced for subjects trained in the morning
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.
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.
Changes During Passive Recovery In Lower Limbs Tiredness After Strenuous WorkoutIOSR Journals
Abstract: Lower limbs tiredness is a widely accepted indicator for recovery state prediction. The study was
designed and purposed to know the rate and trend of lower limbs tiredness recovery after strenuous workout in
passive state. Ten athletes from LNIPE, Gwalior having almost similar anthropometric measurements,
physiological capacity, chronological age(18-19 year), training age(5-6 year), event(sprinters) etc. residing in
same campus having similar daily routine were selected as participant in this experiment. The experiment was
conducted in a highly controlled environment using sophisticate equipments. Target Heart Rate Zone of the
workout lasting for 20 minutes was 80%-90% of their Maximum Heart Rate. Three readings including pre, post
and 30 minutes post workout was considered for both the two tests (Isometric Leg Strength Test and Sergeant
Jump Test) selected for the purpose. rANOVA was employed separately to derive out meaningful information
from the raw data. In both the tests well controlled workout for 20 minutes resulted in significant increase state
of post workout readings. With passage of time after 30 minutes post passive recovery there was no
improvement in state of tiredness. Thus scope of future research is there in planning out means and methods to
promote lower limbs tiredness recovery during this post recovery period.
Keyword: Isometric Leg Strength Test, Sergeant Jump Test, Recovery, rANOVA
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
Methods of developing power to improve acceleration for the non track athleteFernando Farias
IN MOST TEAM-BASED SPORTS
ATHLETES MUST BE ABLE TO
GENERATE EXPLOSIVE MUSCULAR
FORCES TO ACCELERATE,
CHANGE DIRECTIONS, AND THEN
RE-ACCELERATE OVER RELA-
TIVELY SHORT DISTANCES.
THEREFORE, TO BE SUCCESSFUL,
ACCELERATION RATHER THAN
MAXIMAL VELOCITY IS LIKELY A
GREATER PREDICTOR OF SUC-
CESS IN THESE SPORTS. THIS
ARTICLE WILL EXPLORE SOME OF
THE TECHNIQUES COMMONLY
USED TO IMPROVE AN ATHLETE’S
ABILITY TO ACCELERATE BY
IMPROVING FORCE, VELOCITY,
AND THE COMBINATION OF THESE
2 ELEMENTS.
Mechanics of the human hamstring muscles during sprintingFernando Farias
As peak musculotendon
force and strain for BF
LH
, ST, and SM occurred around the same time during terminal swing, it is suggested that this period in the
stride cycle may be when the biarticular hamstrings are at greatest injury risk. On this basis, hamstring injury prevention or rehabilitation
programs should preferentially target strengthening exercises that involve eccentric contractions performed with high loads at longer
musculotendon lengths.
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.
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.
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.
Transfer of strength and power training to sports performance Fernando Farias
The purposes of this review are to identify the factors that contribute to the
transference of strength and power training to sports performance and to pro-
vide resistance-training guidelines. Using sprinting performance as an example,
exercises involving bilateral contractions of the leg muscles resulting in vertical
movement, such as squats and jump squats, have minimal transfer to performance.
However, plyometric training, including unilateral exercises and horizontal
movement of the whole body, elicits signifi cant increases in sprint acceleration
performance, thus highlighting the importance of movement pattern and contrac-
tion velocity specifi city. Relatively large gains in power output in nonspecifi c
movements (intramuscular coordination) can be accompanied by small changes in
sprint performance. Research on neural adaptations to resistance training indicates
that intermuscular coordination is an important component in achieving transfer to
sports skills. Although the specifi city of resistance training is important, general
strength training is potentially useful for the purposes of increasing body mass,
decreasing the risk of soft-tissue injuries, and developing core stability. Hyper-
trophy and general power exercises can enhance sports performance, but optimal
transfer from training also requires a specifi c exercise program.
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.
Effects of Eccentric Strength Training’s Time on Daily Plasma Testosterone Le...IOSR Journals
This study aims to evaluate the effects of the eccentric physical training’s time on daily plasma concentrations of testosterone among sedentary athletes. Sixty male athletes, with homogeneous age, size and weight were selected for the study during three months. They were subjects to a strength training of the extensor and flexor muscles of the knee. After they were divided in two groups of thirty subjects and then had physical training either in the morning between 6 and 7, or in the evening, between 16 and 17. The dosage of testosterone on each athlete was performed before and after submission to an eccentric physical program at the antecubital vein in a restful sitting. Our results have shown that eccentric physical training induces the increase of this steroid hormone in the two groups of athletes and the training in the evening promotes better its production. Our results also showed that the rate of this androgen drop significantly during the day in both groups of athletes trained in the morning or in the evening as well as their respective controls. However, the decline was even more pronounced for subjects trained in the morning
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.
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.
Changes During Passive Recovery In Lower Limbs Tiredness After Strenuous WorkoutIOSR Journals
Abstract: Lower limbs tiredness is a widely accepted indicator for recovery state prediction. The study was
designed and purposed to know the rate and trend of lower limbs tiredness recovery after strenuous workout in
passive state. Ten athletes from LNIPE, Gwalior having almost similar anthropometric measurements,
physiological capacity, chronological age(18-19 year), training age(5-6 year), event(sprinters) etc. residing in
same campus having similar daily routine were selected as participant in this experiment. The experiment was
conducted in a highly controlled environment using sophisticate equipments. Target Heart Rate Zone of the
workout lasting for 20 minutes was 80%-90% of their Maximum Heart Rate. Three readings including pre, post
and 30 minutes post workout was considered for both the two tests (Isometric Leg Strength Test and Sergeant
Jump Test) selected for the purpose. rANOVA was employed separately to derive out meaningful information
from the raw data. In both the tests well controlled workout for 20 minutes resulted in significant increase state
of post workout readings. With passage of time after 30 minutes post passive recovery there was no
improvement in state of tiredness. Thus scope of future research is there in planning out means and methods to
promote lower limbs tiredness recovery during this post recovery period.
Keyword: Isometric Leg Strength Test, Sergeant Jump Test, Recovery, rANOVA
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
Methods of developing power to improve acceleration for the non track athleteFernando Farias
IN MOST TEAM-BASED SPORTS
ATHLETES MUST BE ABLE TO
GENERATE EXPLOSIVE MUSCULAR
FORCES TO ACCELERATE,
CHANGE DIRECTIONS, AND THEN
RE-ACCELERATE OVER RELA-
TIVELY SHORT DISTANCES.
THEREFORE, TO BE SUCCESSFUL,
ACCELERATION RATHER THAN
MAXIMAL VELOCITY IS LIKELY A
GREATER PREDICTOR OF SUC-
CESS IN THESE SPORTS. THIS
ARTICLE WILL EXPLORE SOME OF
THE TECHNIQUES COMMONLY
USED TO IMPROVE AN ATHLETE’S
ABILITY TO ACCELERATE BY
IMPROVING FORCE, VELOCITY,
AND THE COMBINATION OF THESE
2 ELEMENTS.
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
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.
Mats André Zuccarello Aasen, commonly known as Mats Zuccarello, was born on September 1, 1987, in
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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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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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Narrated Business Proposal for the Philadelphia Eaglescamrynascott12
Slide 1:
Welcome, and thank you for joining me today. We will explore a strategic proposal to enhance parking and traffic management at Lincoln Financial Field, aiming to improve the overall fan experience and operational efficiency. This comprehensive plan addresses existing challenges and leverages innovative solutions to create a smoother and more enjoyable experience for our fans.
Slide 2:
Picture this: It’s a crisp fall afternoon, driving towards Lincoln Financial Field. The atmosphere is electric—tailgaters grilling, fans in Eagles jerseys creating a sea of green and white. The air buzzes with camaraderie and anticipation. You park, join the throng, and make your way to your seat. The stadium roars as the Eagles take the field, sending chills down your spine. Each play is a thrilling dance of strategy and skill. This is what being an Eagles fan is all about—the joy, the pride, and the shared experience.
Slide 3:
But now, the day is marred by frustration. The excitement wanes as you struggle to find a parking spot. The congestion is overwhelming, and tempers flare. The delays mean you miss the pre-game excitement, the tailgate camaraderie, and even the opening kick-off. After the game, the joy of victory or the shared solace of defeat is overshadowed by the stress of navigating out of the parking lot. The gridlock, honking horns, and endless waiting drain the energy and joy from what should have been an unforgettable experience.
Our proposal aims to eliminate these frustrations, ensuring that from arrival to departure, your experience is extraordinary. Efficient parking and smooth traffic flow are key to maintaining the high spirits and excitement that make game days special.
Slide 4:
The Philadelphia Eagles are not just a premier NFL team; they are an integral part of the community, hosting games, concerts, and various events at Lincoln Financial Field. Our state-of-the-art stadium is designed to provide a world-class experience for every attendee. Whether it's the thrill of game day, the excitement of a live concert, or the camaraderie of community events, we pride ourselves on delivering a fan-first experience and maintaining operational excellence across all our activities. Our commitment to our fans and community is unwavering, and we continuously strive to enhance every aspect of their experience, ensuring they leave with unforgettable memories.
Slide 5:
Recent trends show an increasing demand for efficient event logistics. Our customer feedback has consistently highlighted frustrations with parking and traffic. Surveys indicate that a significant number of fans are dissatisfied with the current parking situation. Comparisons with other venues like Citizens Bank Park and Wells Fargo Center reveal that we lag in terms of parking efficiency and convenience. These insights underscore the urgent need for innovation to meet and exceed fan expectations.
Slide 6:
As we delve into the intricacies of our operations, one glaring issue emer
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1. ANALYSIS OF MUSCLE ACTIVATION DURING
DIFFERENT LEG PRESS EXERCISES AT
SUBMAXIMUM EFFORT LEVELS
EDUARDO MARCZWSKI DA SILVA, MICHEL ARIAS BRENTANO, EDUARDO LUSA CADORE,
ANA PAULA VIOLA DE ALMEIDA, AND LUIZ FERNANDO MARTINS KRUEL
Grupo de Pesquisa em Atividades Aqua´ticas e Terrestres, Laboratory of Exercise Research,
Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
ABSTRACT
Da Silva, EM, Brentano, MA, Cadore, EL, De Almeida, APV, and
Kruel, LFM. Analysis of muscle activation during different leg
press exercises at submaximum effort levels. J Strength Cond
Res 22: 1059–1065, 2008—Many studies have analyzed
muscle activity during different strength exercises. Although the
leg press (LP) is one of the most common exercises performed,
there is little evidence of lower limb muscle activity patterns
during this exercise and its variations. Thus, this study aimed to
verify how mechanical changes and loads affect lower limb
muscle activity during the performance of different LP
exercises. Fourteen women performed 3 LP exercises: 45°
LP (LP45), LP high (LPH), and LP low (LPL) at 40% and 80% of
the 1 repetition maximum. The electromyographic activity of the
rectus femoris, vastus lateralis, biceps femoris, gastrocnemius,
and gluteus maximus was recorded. Results suggested that
mechanical changes affect lower limb muscle activity and that it
is related to the load used. At moderate effort levels, the rectus
femoris and gastrocnemius were more active during the LP45
and LPL than during the LPH. At a high effort level, the rectus
femoris and vastus lateralis (quadriceps) were more active
during the LPL than the LPH. Again, the rectus femoris and
gastrocnemius were more active during the LP45 and LPL than
the LPH. On the other hand, gluteus maximus activity was
greater during the LPH than the LPL. This study found that
coordination patterns of muscle activity are different when
performing LP variations at high or moderate effort levels
because of mechanical changes and different loads lifted
during the different LP exercises. These results suggest that if
the goal is to induce greater rectus femoris and vastus lateralis
(quadriceps) activation, the LPL should be performed. On the
other hand, if the goal is to induce gluteus maximus activity, the
LPH should be performed.
KEY WORDS electromyography, lower limb muscles, mechan-
ical changes, loads lifted
INTRODUCTION
R
ecently, many studies have analyzed muscle acti-
vity during different strength exercises (14,25,28,
29,37). The superficial electromyographic (EMG)
technique is often used to identify the participa-
tion of a muscle or muscle group in different performance
techniques of many exercises (2–4,6,17,27,33). Exercises com-
monly used in a strength training program seem to be more in-
teresting to analyze during those analyses (20,23,24,35,36,39).
The leg press (LP) is a multijoint (hip, knee, and ankle)
exercise, its variations (low foot placement [LPL], high foot
placement [LPH], and 45° [LP45]) are some of the most
common exercises performed by athletes to enhance per-
formance in sports (11,12). The hip and knee extension
observed during concentric phase on LP is a very important
motion for these individuals because it involves the activation
of large muscle groups of the lower body. The conditioning
of those muscles are directly related to improvement in run-
ning, jumping, and lifting for football, track and field, power
lifting, and Olympic weightlifting athletes (10–12). Identify-
ing how mechanical changes and different loads affect the
activation pattern in hip and knee extensor muscles may
improve physical performance in athletic and nonathletic
populations (10–18).
Caterisano et al. (5) evaluated hip and knee extensor muscle
activity performing squats at 3 ranges of motion. They found
that gluteus maximus and vastus medialis activity was
influenced by different mechanical changes in this exercise
(partial, parallel, and full depth). Escamilla et al. (12) quantified
the hip and knee extensors muscle activity during LPH and
LPL exercises in different stance widths and foot positions.
They found that the peak of EMG activity for the gastro-
cnemius muscle was greater during the LPL than during the
Address correspondence to Eduardo Marczwski da Silva,
eduardomarczwski@yahoo.com.br.
22(4)/1059–1065
Journal of Strength and Conditioning Research
Ó 2008 National Strength and Conditioning Association
VOLUME 22 | NUMBER 4 | JULY 2008 | 1059
2. LPH, indicating that mechanical changes could modify
muscle activity pattern during the performance of LP
exercises. However, only a single voluntary effort level was
used, gluteus maximus muscle activity was not measured, and
the LP45 was not performed during these analyses.
Although the mechanical changes during strength exer-
cises variations can modify muscle activity pattern, studies
have not quantified how mechanical changes affect the hip
and knee extensor muscle activity pattern during LP exercises
at different submaximum loads lifted (5,11,12). Furthermore,
these studies have been done only with men (5,6,12,35–37).
Thus, the specific purpose of this study was to analyze how
mechanical changes and the loads lifted could modify the hip
and knee extensor muscle activity in women during different
LP exercises (LPL, LPH, and
LP45). Based on the findings of
Escamilla et al. (12), Caterisano
et al. (5), Anders et al. (1),
Lawrence and De Luca (26),
and Woods and Bigland-Ritchie
(38), we propose the hypothesis
that muscle activity could differ
during performance of the 3 LP
exercises and that these differ-
ences would depend on the
load lifted.
METHODS
Experimental Approach to the
Problem
Articles in academic journals
and fitness periodicals have
never examined how mechani-
cal changes and loads lifted
affect muscle activity during
LP exercises. Thus, we used 3
of the most common LP varia-
tions to examine which posi-
tions adopted during LP
exercises could elicit the highest
level of electrical activity in 5
lower limb muscles. Electro-
myographic signals were col-
lected from each muscle during
performance of the different LPs
using different submaximum
(40% and 80%) effort levels.
Acquisition of all EMG signals
was performed on the same day
for each subject. According to
convention, the root mean
square of the EMG signal
(rmsEMG) was used to quantify
the average level of electrical
activity produced during each condition. The signals were
normalized by the signal collected during the maximum
repetition of the LP45 to reduce the effect of variations in
signal amplitude among muscles and subjects (37). Compar-
isons were made among exercises at 2 submaximum effort
levels. These procedures were designed to address the
effectiveness of each exercise targeting specific muscles;
however, some controversy regarding their relative efficacy
and safety still exists.
Subjects
Fourteen healthy young women (physical education stu-
dents) from the Federal University of Rio Grande do Sul
(UFRGS) were selected for this study. The participants’ mean
age, height, percentage of lean body mass and fat mass (6SD)
Figure 1. (A) LPL starting concentric position. (B) LPL final concentric position.
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Muscle Activity During Strength Exercises
3. were 21.5 6 1.6 years, 1.63 6 0.06 m, 74.23 6 3.63%, and
26.04 6 3.79%, respectively. Subjects reported an average of
1 hour twice weekly for at least 6 months of strength training.
All subjects had been performing LP exercises for at least
4 months. None of the subjects presented knee or hip injury
or had undergone any knee or hip surgery before the study.
The Ethics Committee of UFRGS approved the study.
Before their participation, all subjects signed a university-
approved informed consent form.
Procedures
In the first week, anthropometric measurements of the
subjects were taken, and they also performed a 1 repetition
maximum (1RM) voluntary test of the LP45, LPH, and
LPL (Figures 1, 2, and 3, respectively) exercises. The
anthropometric protocol con-
sisted of height and weight
measurements as well as body
density assessment using the
skinfold method suggested by
Jackson et al. (21) to later body
fat measurements according to
Heyward and Stolarczyk (19).
In the second step, subjects
performed the 1RM test ran-
domly with the 3 LP exercises,
using a protocol similar to that
previously proposed by Glass
and Armstrong (18), and it was
limited to a maximum of 5 trials
to reach 1RM. The rest period
among trials was 2 minutes and
5 minutes among exercises in
order to avoid problems related
to muscle fatigue (32). Exercise
cadence and range of motion
were controlled by a Quartz
metronome with 1-bÁmin21
res-
olution and a Biometrics elec-
tronic goniometer (model TM
180) (12,36). Subsequently, the
1RM values were used to cal-
culate the submaximum effort
levels (40% and 80% of the
1RM). The starting concentric
position to perform the exer-
cises was set by a manual
goniometer (CARCI), as 90°
of knee flexion during the 3
LP exercises and 90°, 105°, and
125° of hip flexion during the
LPL, LP45, and LPH, respec-
tively (Figures 1A, 2A, and 3A).
The foot position used was that
considered the most comfort-
able for each subject. The final concentric position in all
exercises was set as the full knee extension (Figures 1B, 2B
and 3B) (12). An LP machine with high and low pedals
(Taurus, Porto Alegre, Brazil) and an LP45 machine (Topline,
Porto Alegre, Brazil), both of invariable resistance, were used
to perform the different LP exercises.
Data Collection
Subjects returned for data collection 1 week after the initial
measurements. During this time, they were encouraged to
keep their exercise routine. Myoelectric activity was obtained
by bipolar (20-mm interelectrode distance) surface electrodes
(Noraxon 272) placed longitudinally to the direction of the
muscle fiber on the rectus femoris, gluteus maximus, vastus
lateralis, biceps femoris (long head), and gastrocnemius
Figure 2. (A) LP45 starting concentric position. (B) LP45 final concentric position.
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4. (lateral head), following recommendations by Pincivero et al.
(31) and Rainoldi et al. (34). The reference electrode was
placed over the medial shaft of the tibia ~ 6–8 cm below the
inferior pole of the patella. Before electrode placement, the
skin area was shaved, abraded to reduce skin impedance, and
cleaned with isopropyl alcohol. The EMG signal was
obtained using an 8-channel electromyograph (model
AMT-8 channel; Bortec, Calgary, Alberta, Canada) with
a sample rate of 2000 Hz coupled to a Pentium desktop (200
MHz, 32 Mb RAM) fitted to a digital-analog conversion
plate. The common mode rejection of the current system is
115 dB at 60 Hz with an input impedance of 10 gV. The
electronic goniometer was positioned on the lateral epi-
condyle of the right knee in each subject to set the 90° knee
flexion angle in the starting position of each exercise, as well
as to distinguish the concen-
tric (90°–180° full extension)
and eccentric (180°–90°)
phases during the signal in-
terpretation (12).
The submaximum exercise
protocol was performed ran-
domly as well. First, the sub-
jects performed the 1RM of
the LP45. Subsequently, they
performed 5 repetitions at
40% and 5 repetitions at 80%
of 1RM in each LP exercise
(LPL, LP45, and LPH). All
exercise protocols were per-
formed on the same day.
During the exercise protocol,
both concentric and eccentric
phases were set at about 2
seconds each to reduce the
acceleration effects on the re-
sistance offered by the weight
lifted. The rest period between
exercises was the same allowed
during the 1RM test. Data
acquisition was started at the
beginning of the first repetition
and finished at the end of the
fifth repetition. Between repe-
titions, subjects were instructed
to stop for 1 second at the end
ofconcentricphaseto promote
a clear separation between
them. Finally, the subjects per-
formed the 1RM in LP45
to verify the effect of fatigue
on the EMG signal ampli-
tude. The intraclass correla-
tion coefficient between 1RM
tests was at least 0.92 for
all muscles, indicating no fatigue induced by the exercise
protocol.
Data Analysis
The signal registered during 1RM of the LP45, and only the
signal of 3 central repetitions obtained at submaximum
intensities were analyzed. This procedure was adopted to
avoid problems with signal discrepancies regarding the inertia
at the beginning of exercises, as well as the possibility of
fatigue in the last repetition (12). The EMG signal collected
was analyzed on SAD32 (32 bits, 2.61.05 mp version)
software, developed at the Mechanic Measurements Labo-
ratory of UFRGS. For segmentation and quantification of the
EMG signal, the goniometer’s curves were used to identify
and to separate the concentric and eccentric phases.
Figure 3. (A) LPH starting concentric position. (B) LPH final concentric postion.
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Muscle Activity During Strength Exercises
5. Raw EMG signals were band-pass filtered (Butterworth 5th
order) at 20–500 Hz following the recommendations of
DeLuca (7). To examine the EMG signals in the time
domain, the raw signals were processed through an rms
calculation. The rmsEMG average was obtained from the
3 central submaximum effort repetitions of the LPL, LP45,
and LPH, and the rmsEMG was obtained from maximum
repetition (1RM) of the LP45 for each muscle during the
concentric phase. This treatment was similar to that proposed by
Escamilla et al. (12) and Pincivero et al (31). The rmsEMG mean
collected at 40% and 80% was normalized using the value
collected from different muscles during the 1RM of the LP45
(100%). This procedure was adopted due to limitations on
normalization by isometric actions (7). Muscle activity was
compared in the concentric phase between exercises at 40% and
80% of the 1RM.
Statistical Analyses
The Shapiro-Wilks statistical test was used to determine the
data normality. According to the result, repeated-measures
analyses of variance comparing the exercises (LP45, LPH, and
LPL) for each intensity (40% and 80% of 1RM) were applied
to the 5 muscle activity values to verify the differences in
muscle activity. Subsequently, to determine the source of the
significance, Bonferroni’s post hoc test was used. All statistical
procedures were adopted by using the SPSS 11.0 package for
Windows. Significance was set at p # 0.05.
RESULTS
Figure 4 shows the rmsEMG normalized mean values of
muscle activity among the 3 exercises at 40% and 80%. At
moderate effort levels, rectus femoris and gastrocnemius activity
was greater (p , 0.05) during the LP45 and LPL than during
the LPH (Figure 4A). At high effort level, the rectus femoris and
vastus lateralis (quadriceps) were more active (p , 0.05) in
during the LPL than the LPH. The rectus femoris and
gastrocnemius were more active (p , 0.05) during the LP45 and
LPL than during the LPH. However, during the LPH exercise,
gluteus maximus activity was greater (p , 0.05) than during the
LPL (Figure 4B). No statistical difference was observed in
biceps femoris activity among the 3 exercises (Figure 4).
DISCUSSION
In the present study, we examined young women performing
3 different LP exercises at 2 submaximum effort levels.
The EMG data were analyzed in order to compare muscle
activity among exercises. The principal differences found in
muscle activation patterns are related to the mechanical
changes and effort levels required (40% and 80% of 1RM)
during these exercises.
At the moderate effort level (40%), we found that rectus
femoris and gastrocnemius activity during the performance of
the LP45 and LPL was greater than during the LPH exercise.
However, the same result was found at the high effort level
(80%). It means that the activity patterns of rectus femoris and
gastrocnemius were different among these exercises and did
not depend on the effort level required. This was probably
due to mechanical changes during the performance of these
exercises.
For the rectus femoris, the fact that it is a biarticular (hip and
knee) muscle can explain these differences (10–12). Escamilla
(10) suggested that the greater rectus femoris activity found
during monoarticular exercises (knee extension) compared to
biarticular exercises (LP and
squat) for the lower limbs can
be explained by its biarticular
function. When comparing dif-
ferent types of LP, it can be
verified that during the LPH at
the starting position, the high
foot placement increases the
hip flexion angle (the biceps
femoris and gluteus maximus
are stretched and the rectus
femoris is shortened). This
could impair the rectus femoris
mechanism that shortens this
muscle. Thus, it would result in
a strength deficit because, in
that position, the rectus femoris
would not be at a favorable
length to increase force pro-
duction (8,9,30). On the other
hand, in the LP45 and LPL
exercises, the rectus femoris
would not be as shortened,
Figure 4. Root mean square electromyographic values of the muscle activity of rectus femoris (RF), vastus lateralis
(VL), biceps femoris (BF), gastrocnemius (GAS), and gluteus maximus (GM) muscles during different types of
leg press exercises at a 40% effort level (a
difference from LPH, p , 0.05) (A) and during different types of leg
press exercises at an 80% effort level (b
difference from LPL, p , 0.05) (B).
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6. thus increasing its force production capacity. Our result was
different from that of Escamilla et al. (12). Probably the
different hip ankle positions used during LPH and LPL
performance can explain these differences. For the gastroc-
nemius muscle, similar results were previously reported by
Escamilla et al. (12), although only the LPL and LPH were
compared in their study. These results were explained by the
subjects’ different ankle joint positions adopted during the 3
exercises. During the LPH, the subject’s ankle is positioned at
a greater degree of plantar flexion compared to its position
during the LP45 and LPL. This causes a shortening of the
gastrocnemius muscle (17), which can impair the mechanics
of the gastrocnemius during this exercise, suggested again by
the relationship between force production and muscle length
(force-length curves) (8,9,30).
On the other hand, at the high effort level (80%), we found
that vastus lateralis activity was greater during the LPL than
during the LPH and that gluteus maximus activity was greater
during the LPH than during the LPL. It means that activity
patterns of the vastus lateralis and gluteus maximus were dif-
ferent between these exercises, depending on the effort level
required. It probably was a result of mechanical changes in
the arrangement of the loads lifted while performing these
exercises.
A specific requirement of the vastus lateralis can occur
during the LPL, but it happened only at the high effort level,
confirming the different result obtained from that found by
Escamilla et al. (12). Woods and Bigland-Ritchie (38) found
nonlinear force–EMG relationships in muscles of mixed fiber
composition. They suggested that at the low to moderate
effort level, low threshold units would be selectively
recruited, while at the high effort level, high threshold units
would be responsible for increasing the EMG signal.
According to Johnson et al. (22), the vastus lateralis muscle
consisted of approximately 45% of type I fibers and 55% of
type II. Thus, selective recruitment of type II fibers at
increasing force levels (80%) in the vastus lateralis may still be
responsible for increasing the EMG signal at the high effort
level. It suggests that coordination patterns are different from
the high to moderate effort levels (1,25). This finding
combined with the rectus femoris results indicates that the
quadriceps muscle group (rectus femoris and vastus lateralis)
appears to require more mechanical changes during the LPL
than the LPH, indicating a specific activity of these muscles
mainly at the high effort level (80%).
For the gluteus maximus, this finding supports the
suggestions of Caterisano et al. (5) that a greater angle of
hip motion could increase gluteus maximus activity during
LPH performance. Compared to the other exercises, in the
starting position, the greater hip flexion angle observed could
be favorable to gluteus maximus force production (8,9,30).
We suggest that the high gluteus maximus activity during the
LPH helps the deficit caused by the rectus femoris and
gastrocnemius muscles. However, this result was found only
at the high effort level. According to Johnson et al. (22), the
gluteus maximus muscle consisted of approximately 40%–
70% of type I fibers and 30%–60% of type II fibers. Thus,
selective recruitment of type II fibers at increasing force levels
in the gluteus maximus may still be responsible for the
increased EMG signal at the high effort level. Again, it sug-
gests that coordination patterns are different from the high to
moderate effort levels (1,26). No difference was observed
between exercises in biceps femoris activity, in agreement
with the results found by Escamilla et al. (12).
In conclusion, the results presented suggest that the
mechanical changes in LPL, LP45 and LPH performance
affect coordination activity patterns in women’s lower limb
muscles. The differences can be related to the load lifted
(effort level) during these exercises.
PRACTICAL APPLICATIONS
LP exercises (LPL, LPH, and LP45) are commonly
performed in strength training programs. Due to the fact
that the primary purpose of the LP exercises is the devel-
opment of increased strength during knee and hip extension
simultaneously, identifying the participation of the different
muscles involved in these exercises at different loads is very
important to coaches, athletes, and general people. The
results of our study indicate that when a load at 40% of 1RM is
selected, LPL and LP45 are recommended to strengthen the
rectus femoris and gastrocnemius muscles. When a load at
80% of 1RM is selected, the exercises recommended to
strengthen the rectus femoris and gastrocnemius are the
same. To strengthen the quadriceps (rectus femoris and vastus
lateralis) muscle, we recommend performing the LPL
exercise. On the other hand, to strengthen the gluteus
maximus muscle, the LPH exercise should be performed.
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