CAFFEINE AND ENERGY DRINKS
ARE POPULAR SUPPLEMENTS THAT
HAVE VARIABLE USES IN BOTH
ATHLETIC AND NONATHLETIC POP-
ULATIONS. EVIDENCE HAS BEEN
RELATIVELY CONSISTENT IN
SHOWING THE EFFICACY OF THESE
“HIGH-ENERGY” COMPOUNDS IN
ENHANCING ENDURANCE PERFOR-
MANCE, BUT LESS IS UNDERSTOOD
REGARDING ITS ERGOGENIC PO-
TENTIAL IN STRENGTH/POWER AC-
TIVITIES. THIS REVIEW FOCUSES ON
THE EFFICACY ON THESE PROD-
UCTS (CAFFEINE BY ITSELF OR IN
COMBINATION WITH OTHER INGRE-
DIENTS) ON STRENGTH/POWER
PERFORMANCE AND REACTION
TIME. IN ADDITION, DISCUSSION ON
THE EFFICACY OF CAFFEINE DUR-
ING PROLONGED ACTIVITY AND ITS
ROLE DURING TACTICAL PERFOR-
MANCE IS ADDRESSED.
THE ABILITY TO EXPRESS HIGH
POWER OUTPUTS IS CONSIDERED
TO BE ONE OF THE FOUNDA-
TIONAL CHARACTERISTICS
UNDERLYING SUCCESSFUL PER-
FORMANCE IN A VARIETY OF
SPORTING ACTIVITIES, INCLUDING
JUMPING, THROWING, AND
CHANGING DIRECTION. NUMER-
OUS TRAINING INTERVENTIONS
HAVE BEEN RECOMMENDED TO
ENHANCE THE ATHLETE’S ABILITY
TO EXPRESS HIGH POWER OUT-
PUTS AND IMPROVE THEIR OVER-
ALL SPORTS PERFORMANCE
CAPACITY. THIS BRIEF REVIEW
EXAMINES THE FACTORS THAT
UNDERLIE THE EXPRESSION OF
POWER AND VARIOUS METHODS
THAT CAN BE USED TO MAXIMIZE
POWER DEVELOPMENT
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.
How Small-Sided and Conditioned Games Enhance Acquisition of Movement and Dec...Fernando Farias
Such traditional methods provide a limited scope for
action variability in learners because a key aim of practitioners
is to decrease uncertainty of actions and rationalize decision-
making processes in training drills. Despite these reported bene-
fits, traditional utilization of practice drills has been criticized
because they neglect the active role of the performance envi-
ronment in shaping movement behavior and decision making
(10), sustaining a dysfunctional rupture in the performer-
environment relationship (cf. the concept of organismic asym-
metry in sports science (9)).
THE ABILITY TO EXPRESS HIGH
POWER OUTPUTS IS CONSIDERED
TO BE ONE OF THE FOUNDA-
TIONAL CHARACTERISTICS
UNDERLYING SUCCESSFUL PER-
FORMANCE IN A VARIETY OF
SPORTING ACTIVITIES, INCLUDING
JUMPING, THROWING, AND
CHANGING DIRECTION. NUMER-
OUS TRAINING INTERVENTIONS
HAVE BEEN RECOMMENDED TO
ENHANCE THE ATHLETE’S ABILITY
TO EXPRESS HIGH POWER OUT-
PUTS AND IMPROVE THEIR OVER-
ALL SPORTS PERFORMANCE
CAPACITY. THIS BRIEF REVIEW
EXAMINES THE FACTORS THAT
UNDERLIE THE EXPRESSION OF
POWER AND VARIOUS METHODS
THAT CAN BE USED TO MAXIMIZE
POWER DEVELOPMENT
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.
How Small-Sided and Conditioned Games Enhance Acquisition of Movement and Dec...Fernando Farias
Such traditional methods provide a limited scope for
action variability in learners because a key aim of practitioners
is to decrease uncertainty of actions and rationalize decision-
making processes in training drills. Despite these reported bene-
fits, traditional utilization of practice drills has been criticized
because they neglect the active role of the performance envi-
ronment in shaping movement behavior and decision making
(10), sustaining a dysfunctional rupture in the performer-
environment relationship (cf. the concept of organismic asym-
metry in sports science (9)).
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.
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.
HIGH-INTENSITY CIRCUIT TRAINING USING BODY WEIGHTFernando Farias
Traditionally, resistance training often is
performed separately from aerobic training V
typically on two or three nonconsecutive days
each week. The American College of Sports
Medicine (ACSM) recommends 8 to 12 repeti-
tions of a resistance training exercise for each
major muscle group at an intensity of 40% to 80%
of a one-repetition max (RM) depending on the
training level of the participant.
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
The Effects Of Creatine On Repeated Sprint Performance, Maximum Strength And ...Carl Page
Working as part of a research team investigating the effects of creatine on repeated sprint performance, maximum strength and power.
The nutritional supplement creatine has been gaining popularity exponentially over the past decade, so much so, that it is one of the most widely used Ergogenic aids. Theoretically, an increase in creatine stores within the muscle may enhance the rate of ATP synthesis and PCr resynthesis during high-intensity exercise, and therefore, improve performance. However, within the scientific literature the effects of creatine on exercise performance remain equivocal.
Parameters that are easy and inexpensive to measure and which will not disturb the training process should be preferred in the diagnosis of overtraining.
Unfortunately, a valid parameter that can help coaches and athletes to control training is difficult to find. Moreover, an individual response is very different; therefore athletes should be monitored continuously and analyzed individually. Much of this can be done by athletes themselves during everyday training.
Self-assessment should include:
* Measurement of heart rate during rest
* Subjective assessment of the individual state
* Subjective assessment of workout intensity
Poster presentation at the 2015 Ouachita Baptist University Scholar's Day displaying the results of my research project about the effects of caffeine on muscular endurance.
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.
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.
HIGH-INTENSITY CIRCUIT TRAINING USING BODY WEIGHTFernando Farias
Traditionally, resistance training often is
performed separately from aerobic training V
typically on two or three nonconsecutive days
each week. The American College of Sports
Medicine (ACSM) recommends 8 to 12 repeti-
tions of a resistance training exercise for each
major muscle group at an intensity of 40% to 80%
of a one-repetition max (RM) depending on the
training level of the participant.
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
The Effects Of Creatine On Repeated Sprint Performance, Maximum Strength And ...Carl Page
Working as part of a research team investigating the effects of creatine on repeated sprint performance, maximum strength and power.
The nutritional supplement creatine has been gaining popularity exponentially over the past decade, so much so, that it is one of the most widely used Ergogenic aids. Theoretically, an increase in creatine stores within the muscle may enhance the rate of ATP synthesis and PCr resynthesis during high-intensity exercise, and therefore, improve performance. However, within the scientific literature the effects of creatine on exercise performance remain equivocal.
Parameters that are easy and inexpensive to measure and which will not disturb the training process should be preferred in the diagnosis of overtraining.
Unfortunately, a valid parameter that can help coaches and athletes to control training is difficult to find. Moreover, an individual response is very different; therefore athletes should be monitored continuously and analyzed individually. Much of this can be done by athletes themselves during everyday training.
Self-assessment should include:
* Measurement of heart rate during rest
* Subjective assessment of the individual state
* Subjective assessment of workout intensity
Poster presentation at the 2015 Ouachita Baptist University Scholar's Day displaying the results of my research project about the effects of caffeine on muscular endurance.
Abstract
Background and purpose: Diet and muscle fiber type are all major factors in predicting intramuscular carnosine concentration [1]. Constituent substrate availability, including the amino acids L-histidine and more specifically beta alanine, play the greatest role in determining the concentration of intramuscular carnosine, a potent intracellular Hydrogen ion buffer. The purpose of this review is to analyze the efficacy of beta alanine supplementation on exercise performance, specifically activities relying on anaerobic glycolysis.
Method: The review included articles from peer-reviewed journals with sufficient data related to the purpose and focus of the study. Inclusion criteria included randomized control trials, systematic reviews and meta-analysis published since 2007.
Results: Twenty relevant studies were identified; various experimental protocols were employed, including both acute and chronic effects of beta alanine supplementation on physical performance. All studies were published 2007 through 2017, providing a robust overview of experimentation over the last 10 years.
Discussion and conclusion: Among studies analyzed in this mini-review, the consensus reached regarding the efficacy of beta alanine supplementation for performance enhancement was relatively positive. Most studies followed similar supplementary strategies, consuming anywhere from 1.6 to 6.4g/day for 2 to 10 weeks. The majority of these studies demonstrated statistically significant increases in intramuscular carnosine content, a physiological parameter that is positively correlated with sprinting and power performance. Many studies presented results in support of enhanced muscular endurance performance subsequent to supplementation relative to the placebo group. Researchers also noted a decline in peak aerobic capacity concurrent to a delay in the onset of blood lactate accumulation, supporting the notion of enhanced glycolytic capacity. More research is necessary to identify optimal dosing strategies for performance optimization across the spectrum of physical activities.
Learn about which sports supplements and ergogenic aids are effective! Registered Dietitian Nutritionist David Wiss MS RDN shares the latest research and his professional experience.
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fatigue following a
soccer match is multifactorial and related to dehydration,
glycogen depletion, muscle damage and mental fatigue. A
multitude of recovery strategies are currently implemented
in professional soccer clubs to target these causes of fatigue.
Recovery strategies aimed at reducing acute inflammation
from muscle damage and enhancing its rate of removal are
particularly used in professional soccer settings.
Effect of Body Combat exercises on selected physical fitness components of sc...Sports Journal
The objective of the study was to assess the effect of body combat exercises on selected physical fitness components of school boys aged 14-16 years. Fifty (50) boys, aged from 14-16 years, were volunteered as subjects for this study. The selected variable for the study was cardiovascular endurance and muscular strength and for measuring cardiovascular endurance and muscular strength Harvard Step Test and sit-up tests were taken into consideration. Body combat exercises were intervened for the period of eight (8) weeks. This experimental design consists of an experimental group which was compared with a control group for the testing the effects of Body Combat exercise training program on cardiovascular endurance and muscular strength component. This experimental design was Non-equivalent control groups Design (pretest/post-test) where the experimental group received the Body combat exercise training program and the control group did not. The collected data were analyzed by using One Way ANCOVA. It was found that after the Eight weeks training programme there was a significant improvement in the cardiovascular endurance and Muscular Strength of school boys.
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.
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.
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.
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.
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.
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.
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.
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.
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)
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”.
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.
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.
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...
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Caffeine, energy drinks, and strength power performance
1. Caffeine, Energy Drinks,
and Strength-Power
Performance
William P. McCormack, MA and Jay R. Hoffman, PhD, FNSCA
Sport and Exercise Science, University of Central Florida, Orlando, Florida
S U M M A R Y
CAFFEINE AND ENERGY DRINKS
ARE POPULAR SUPPLEMENTS THAT
HAVE VARIABLE USES IN BOTH
ATHLETIC AND NONATHLETIC POP-
ULATIONS. EVIDENCE HAS BEEN
RELATIVELY CONSISTENT IN
SHOWING THE EFFICACY OF THESE
“HIGH-ENERGY” COMPOUNDS IN
ENHANCING ENDURANCE PERFOR-
MANCE, BUT LESS IS UNDERSTOOD
REGARDING ITS ERGOGENIC PO-
TENTIAL IN STRENGTH/POWER AC-
TIVITIES. THIS REVIEW FOCUSES ON
THE EFFICACY ON THESE PROD-
UCTS (CAFFEINE BY ITSELF OR IN
COMBINATION WITH OTHER INGRE-
DIENTS) ON STRENGTH/POWER
PERFORMANCE AND REACTION
TIME. IN ADDITION, DISCUSSION ON
THE EFFICACY OF CAFFEINE DUR-
ING PROLONGED ACTIVITY AND ITS
ROLE DURING TACTICAL PERFOR-
MANCE IS ADDRESSED.
INTRODUCTION
T
he popularity of high-energy
drinks seems to be increasing
on an annual basis. Recent evi-
dence suggests that energy drinks are
available in more than 140 countries,
and sales in 2011 were expected to be
in excess of $9 billion (61). Marketing
strategies are aimed at young, athletic
populations. Supplement companies are
frequently serving as event sponsors,
and their products are endorsed by
competitive athletes. The success of
these strategies is evidenced by reports
indicating that half of the energy drinks
are sold to individuals of 25 years and
younger (61). Hoffman et al. (40) repor-
ted that 31.5% of adolescents self-admit
using high-energy drinks, whereas oth-
ers have suggested that 30%–50% of
adolescents and young adults (61) and
nearly half of intercollegiate athletes
consume energy drinks (70).
The primary ingredient in energy drinks
is caffeine. However, to enhance the
effect of caffeine, many of these drinks
contain several additional ingredients to
provide a synergistic or additive effect.
The efficacy of caffeine, and various
combinations of caffeine and other
ingredients has been well-established
regarding endurance performance
(10,14,16–18,31,44,45). Studies have
shown that caffeine enhances perfor-
mance in running and cycling trials to
exhaustion (18,34,35,42,53,56), rowing
(9), and swimming (15). However,
research has been equivocal when exam-
ining the effect of caffeine on strength-
power performance. The focus of this
review is to provide a clearer understand-
ing of the ergogenic role that caffeine and
energy drinks have on strength, power,
and anaerobic exercise performance.
MECHANISM OF ACTION
Caffeine is a central nervous system
(CNS) stimulant, and its effects are sim-
ilar yet weaker than those associated
with amphetamines. Caffeine is used
as an ergogenic aid by both aerobic
and anaerobic athletes. However, the
mechanism of action for these athletes
may be quite different. For the aerobic
athlete, caffeine is thought to prolong
endurance exercise. The mechanisms
that have been proposed to cause this
effect involve an increase in fat oxida-
tion by mobilizing free fatty acids
from adipose tissue or intramuscular
fat stores (1,14,16,17,20,44,45,62). The
greater use of fat as a primary energy
source will slow glycogen depletion and
delay fatigue. However, there have been
a number of researchers who have ques-
tioned this mechanism (32,33,36,46).
During short-duration high-intensity
exercise, the primary ergogenic effect
attributed to caffeine supplementation
is enhanced power production. There
are a number of possible mechanisms
that have been reported to explain the
effect of caffeine on strength-power per-
formance. These mechanisms include
action on both the CNS and neuromus-
cular systems. One of the most signifi-
cant effects of caffeine on the CNS is its
action as an adenosine antagonist, pos-
sibly delaying fatigue by binding to
adenosine receptors, reducing the inhib-
itory effects of adenosine (4,29). In
a meta-analysis by Warren et al. (69), it
was suggested that the effect of caffeine
on the CNS is the most likely source of
improvement in strength-power perfor-
mance by enhancing muscle activation
(motor unit recruitment). In addition,
there is evidence that supports caffeine
as an analgesic, lowering pain and
K E Y W O R D S :
sports nutrition; supplements; ergo-
genic aids
Copyright Ó National Strength and Conditioning Association Strength and Conditioning Journal | www.nsca-scj.com 11
2. ratings of perceived exertion (18,27,54).
There is also evidence suggesting that
caffeine produces an enhanced excita-
tion-contraction coupling, affecting
neuromuscular transmission and mobili-
zation of intracellular calcium ions
from the sarcoplasmic reticulum (64).
Caffeine is also thought to enhance
the kinetics of glycolytic regulatory
enzymes, such as phosphorylase (62).
The exact mechanism to explain the
effect of caffeine on strength-power per-
formance is not clearly defined at this
time. However, there is evidence to sup-
port both central and peripheral factors
that contribute to this effect (4,29).
EFFECT OF CAFFEINE AND
ENERGY DRINKS ON STRENGTH
AND POWER PERFORMANCE
The evidence supporting caffeine alone
as an ergogenic aid in strength, power,
and anaerobic activities seems to be
inconclusive. When caffeine is ingested
in relative dosages of 5 to 6 mg/kg body
weight, significant increases in acute
strength and power performance, as well
as increases in training volume, have
been reported (3,5,6,21,28). A significant
increase in maximal bench press strength
has been observed in resistance-trained
women after caffeine ingestion (28).
Others have shown that acute caffeine
ingestion can improve peak torque and
power in the first of 2 bouts of isokinetic
knee extension/flexion exercise (5) and
increase contraction velocity during
elbow flexion (6). Increases in training
volume (repetitions performed) have
also been demonstrated after acute caf-
feine ingestion in the first 2 sets of per-
forming the leg press to exhaustion (3),
knee extension/flexion (5), and bench
press to exhaustion at 60% of 1 repetition
maximum (1RM) (21). In contrast, no
changes in 1RM in the bench press
and leg extension exercises were seen
in untrained male subjects after an inges-
tion of 400 mg of caffeine (37). Similarly,
a 6 g/kg ingestion of caffeine was unable
to enhance strength performance during
maximal effort isometric plantar flexion
exercise (23).
Several studies examining the effect of
preexercise energy drink consumption
have shown significant increases in
training volume (number of repetitions
performed) and power performance
(24,26,30,43). These preexercise energy
drinks often contain an “energy matrix”
that may contain caffeine, taurine, and
glucuronolactone. However, they also
contain additional ingredients such as
amino acids, creatine, and beta-alanine.
These other ingredients are not designed
to provide an energy boost for acute ex-
ercise performance but to enhance recov-
ery and provide the daily intake of these
compounds to increase strength and
power performance. The latter reasons
are more of a marketing tool that mini-
mizes the number of supplements that
athletes need to consume on a daily basis.
In regards to the effect of these propriety
energy blends on enhancement of train-
ing volume, the results of these studies
have consistently supported the market-
ing claims of greater training volume.
Typically, the ingestion of these propriety
blends 10 minutes before a workout
have been demonstrated to significantly
increase the total number of repetitions
performed during resistance exercise
varying between 4 and 6 sets (30,43).
In addition, the average peak and mean
power for repetitions performed have
also been shown to be significantly
higher in subjects consuming these
high-energy blends (30) (see Figure 1).
Others have shown that an energy
matrix using the same ingredients dis-
cussed above, but with an additional car-
bohydrate load (21.5 g of sucrose, 5.25 g
of glucose, and 50 mg of inositol) (mar-
keted as Red Bull) was shown to signif-
icantly improve the total number of
repetitions performed during 3 sets of
bench press exercise (24).
The use of energy drinks may also
have efficacy in maintaining strength
performance after exhaustive exercise.
Ganio et al. (26) showed that subjects
ingesting an energy drink (containing
195 mg/L caffeine, 1.92 g/L taurine,
46 mg/L carnitine, and electrolytes in
a 7% carbohydrate solution) after
120 minutes of cycling exercise (inten-
sity alternated between 61 and 75% of
V̇O2max) were able to maintain maxi-
mal strength performance in a leg
extension exercise compared with
subjects consuming a placebo (26).
Although energy drink ingestion has
been shown to be efficacious in regards
to enhancing training volume and
power performance during resistance
training, the ability of energy drinks
to enhance anaerobic power during
high-intensity exercise seems limited.
No improvements have been noted in
a 30-second Wingate anaerobic power
test (WAnT) after ingestion of an en-
ergy drink containing anhydrous caf-
feine and several herbal and botanical
compounds, including yohimbine,
evodiamine, hordenine, tyramine, and
tyrosine (41). These compounds are
suggested to provide a stimulatory
effect. Similarly, consumption of coffee
enriched with 450 mg of caffeine, 1.2 g
of garcinia cambogia, 360 mg of citrus
aurantium, and 225 mg of chromium
polynicotinate had no ergogenic bene-
fit on peak power, mean power, time to
peak power, fatigue index, and total
work in the WAnT (42). The use of
the Red Bull energy drink also had
no ergogenic benefit during multiple
WAnT trials (24).
EFFECT OF CAFFEINE AND
ENERGY DRINKS ON SPRINT,
AGILITY, AND REACTION TIME
Caffeine ingestion has been demon-
strated to provide an ergogenic effect
on repeated sprint performance during
both running and cycling modes of
exercise (25,47,57,58,60,63). Acute caf-
feine intake before exercise has been
reported to improve repeated sprint per-
formance for subjects performing 5 sets
of 6 3 20 m sprints (58) and repeated 30-
second sprints on a cycle ergometer (57).
Schneiker et al. (60) reported significant
improvements in sprint performance
during two 36-minute simulated game
halves, with each half containing 18 3
2-minute blocks of 4-second sprints with
120 seconds of recovery (both active and
passive) after caffeine ingestion. This
study simulated the physiologic
demands of a team sport and suggests
that caffeine may be able to maintain
sprint performance during a competitive
contest. In a similar study, Stuart et al.
(63) also observed greater repeated
sprint performance during a simulated
rugby contest after caffeine ingestion.
Efficacy of Caffeine and Energy Drinks
VOLUME 34 | NUMBER 4 | AUGUST 201212
3. Others have shown that acute ingestion
of a proprietary blend of caffeine, crea-
tine, and amino acids ingested 30
minutes before treadmill sprint drills
will result in an improvement in anaer-
obic running capacity at 110%, 105%,
and 100% of peak velocity (25) (see
Figure 2). Caffeine also appears to aug-
ment performance above that seen from
other supplements. Lee et al. (47), after
a 5-day loading dose of creatine that
increased repeated sprint performance,
showed that the addition of an acute
intake of caffeine (6 mg/kg) is able to
stimulate further improvements in power
outputs during intermittent high-intensity
sprints on a cycle ergometer.
Acute ingestion of caffeine or energy
drinks also appears to have some poten-
tial beneficial effects on agility perfor-
mance and reaction time (2,22,
41). Caffeine ingestion appears to be ben-
eficial in competitive athletes for impro-
ving reactive agility in both fresh and
fatigue situations (22), including a rugby
game (63). However, this may be limited
to trained individuals as no ergogenic
effect was observed in untrained individ-
uals performing the proagility test after
caffeine supplementation (49). Several
studies have demonstrated that energy
drinks may have a significant effect
on reactive ability and increase con-
centration, focus, and memory
(2,41). This may have important
implications for tactical personnel
(e.g., military, police, and fire/rescue).
In a military environment, caffeine
ingestion has been shown to improve
vigilance, psychomotor performance,
shooting accuracy, learning, memory,
and mood state in ground and aviation
operations (11,48,50–52,65).
CAFFEINE USE IN OPERATIONAL/
TACTICAL SETTINGS
In a unique environment where
strength, power, and anaerobic fitness
are essential for success, U.S. Air Force
centrifuge riders showed a significant in-
crease in their relaxed G-tolerance after
ingestion of an energy drink containing
5 mg/kg body weight of caffeine along
with a number of other ingredients in-
cluding proprietary amounts of taurine,
L-theanine, fructose, among others. Re-
laxed G-tolerance is measured while the
centrifuge accelerates at 0.1 g/second
with the rider sitting relaxed in the cen-
trifuge gondola, looking straight ahead at
a light bar. Relaxed G-tolerance is that
point when the riders loses 100% of their
peripheral vision and 50% of their central
vision. Even though there was a signifi-
cant increase in relaxed G-tolerance,
there was no benefit shown during sim-
ulated air combat maneuvering, where
the centrifuge was alternated every 15
seconds between +4.5 Gz and +7.0 Gz
in these same riders for up to 15 repeti-
tions. There was also no effect seen dur-
ing a rapid Gz onset ride to +6 Gz (68).
However, in the same study, hip adduc-
tor strength was 37% lower in the pla-
cebo session than in the caffeine session.
Strength and power are important dur-
ing the high-g environment encountered
in fighter and attack aircraft operations
because of the deleterious effect the
G-forces have on the ability of the heart
to deliver blood to the brain. Each
additional “G” above the 1G experienced
on earth reduces the cerebral blood pres-
sure by approximately 20 mmHg.
Strength and power are required to per-
form what is termed an anti-G straining
maneuver (AGSM). During an AGSM,
a maximal isometric contraction is per-
formed in the peripheral musculature to
try to reduce pooling of blood, while
a maximal Valsalva maneuver is
Figure 1. Average peak and mean power during resistance exercise. Supp 5 sup-
plement; PLA 5 placebo.*Significant difference (p , 0.05) between the
groups. Data from Gonzalez et al. (30).
Figure 2. Time to exhaustion at each percentage of peak velocity for ACT and PL
testing sessions. *Significant difference (p , 0.05) between the groups.
ACT 5 supplement; Pl 5 placebo. Data from Fukuda et al. (25).
Strength and Conditioning Journal | www.nsca-scj.com 13
4. performed. The Valsalva maneuver is
where maximal pressure is generated
against a closed glottis to increase driving
pressure in the chest (71). A similar ma-
neuver is seen during maximal efforts in
the weight room. This AGSM can
enhance G-tolerance by as much as 3–
4 gs in trained personnel (55).
In military aviation, alertness and reac-
tion time are critical to successful com-
pletion of missions. Several approaches
have been used to maximize the poten-
tial for success. These methods have
included both nonpharmacological
and pharmacological interventions. On
the nonpharmacological side, the serv-
ices have policies in effect that state
required rest for aircrew. During combat
operations, there are many times when
operational needs override the policies
for aircrew rest. The pharmacologic
interventions have included the use of
caffeine in Operation Southern Watch
in the 1990s (7) to the use of dextro-
amphetamines and modafinil during
prolonged flight operations during the
wars in Iraq and Afghanistan. As stated
previously, the use of these pharmaco-
logic interventions is secondary to ade-
quate rest and is under the supervision
of the military medical community (66).
DOSE RESPONSE
There appears to be a dose response
with caffeine supplementation in
strength-power performance. The nor-
mal dose in most studies showing a pos-
itive effect of caffeine supplementation is
5–6 mg/kg body weight. This would
mean that the average dose for a person
weighing 175 pounds (80 kg) would be
approximately 400 mg of caffeine. For
comparison, a generic cup of drip coffee
contains between 110 and 150 mg of
caffeine per 8 oz. (38). A 12 oz Coca
Cola or Pepsi contains between 30 and
40 mg of caffeine. Energy drinks typically
contain between 75 and 80 mg of caf-
feine per 8 oz; however, there are some
energy drinks that contain as much as
174 mg per serving (39,59). No signifi-
cant effects have been seen from low
caffeine doses (up to 2.1 mg/kg body
weight) in studies examining multiple
sprints, grip strength, and repetitions in
the bench press exercise (8,12,19).
DOES CAFFEINE INGESTION POSE
A RISK OF CAUSING A POSITIVE
DRUG TEST?
Currently the World Anti-Doping
Agency (WADA) lists caffeine as part
of its monitoring program, meaning caf-
feine levels are still tested for and
reported after urine testing, but it is not
banned from use. Caffeine was removed
from the WADA banned list in 2004.
However, the National Collegiate Ath-
letic Association (NCAA) still lists caf-
feine as a “drug subject to restrictions”
if concentrations in urine exceed 15
mg/mL. The NCAA does not list an
equivalent dosage required to test posi-
tive because there are a number of con-
founding factors, but it states that the
cutoff is set so that moderate caffeine
consumption will not cause a positive
test. In a study by Van der Merwe et al.
(67), they found that a dose of approxi-
mately 17.53 mg/kg of caffeine, which
would be equivalent to 8 to 10 cups of
coffee, produced a urinary caffeine level
of 14 mg/mL still below the NCAA cut-
off level to 15 mg/mL. In addition to
caffeine, guarana seed extract is listed
as part of the stimulant group banned
by NCAA. Tuarine, L-theanine, green
tea extract are listed as “Impermissible”
by the NCAA, which means institutions
may not supply these to their student
athletes. Intercollegiate athletes should
check with their coaches and medical
staff before consuming energy drinks.
Athletes competing under the rules of
the United States Anti-Doping Agency
should also check this organization’s
rules before consuming energy drinks.
PRACTICAL APPLICATIONS
Caffeine and energy drinks do appear
to have an ergogenic effect on
strength-power performance. Specifi-
cally, evidence is quite consistent in that
supplementing with caffeine or an en-
ergy drink containing caffeine and other
ingredients can increase the quality of
a workout by increasing the number of
repetitions performed and the power
output per repetition. This may have
important implications for long-term
strength and power development
because the stimulus to the muscle is
greater from these training sessions.
Evidence is also clear that the use of
a ”high-energy” supplement can impact
athletic performance by delaying fatigue
and improving reaction time. Thus, the
ergogenicity of caffeine by itself and in
combination with other synergistic
ingredients can provide a competitive ad-
vantage to athletes. The ergogenicity of
caffeine does appear to be dose related. It
appears that a minimal dose of 5–6 mg/
kg body weight is needed to enhance
performance. The mechanism for an in-
crease in performance is unclear at this
point, but there is compelling evidence
that suggests that both the CNS and
neuromuscular system play a role. More
research is needed in this area to clearly
define the mechanisms at work.
As in all supplements, energy drinks
and caffeine supplementation need to
be taken with care. The Food and
Drug Administration does not regulate
the ingredients found in energy drinks.
The adverse effects reported after en-
ergy drink consumption include in-
somnia, nervousness, headache, and
tachycardia (13). If a person has a car-
diovascular problem, supplementation
with energy drinks or caffeine should
be discussed with a doctor.
William P.
McCormack is
a Doctoral
student at the
University of
Central Florida.
Jay R. Hoffman
is a professor and
department chair
of the Sport and
Exercise Science
Program at
University of
Central Florida.
REFERENCES
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Efficacy of Caffeine and Energy Drinks
VOLUME 34 | NUMBER 4 | AUGUST 201214
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Efficacy of Caffeine and Energy Drinks
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