This study investigated the effects of post-activation potentiation (PAP) using maximum isometric contractions on peak power output in college football players. Twelve players performed vertical jump and back squat tests both with and without preceding PAP. PAP involved a six-second maximum voluntary isometric contraction in the back squat position. Mean vertical jump and back squat peak powers were 8-12% higher with PAP but differences were not statistically significant. While PAP may provide small improvements in power, the study was underpowered and larger samples are needed to determine if PAP using maximum isometric contractions can effectively enhance athletic performance.
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.
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 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.
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.
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.
Does strength training change your movement patterns?Fernando Farias
Most of us in this industry believe that good movement patterns make someone
a better athlete, as well making them less likely to get injured. Unsurprisingly,
therefore, a lot of programs have been put together to help you improve your
movement patterns.
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.
Muscular strength, functional performances and injury risk in professional an...Fernando Farias
Muscle strength and anaerobic power of the lower extre-
mities are neuromuscular variables that influence perfor-
mance in many sports activities, including soccer. Despite
frequent contradictions in the literature, it may be assumed
that muscle strength and balance play a key role in targeted
acute muscle injuries. The purpose of the present study was
to provide and compare pre-season muscular strength and
power profiles in professional and junior elite soccer players
throughout the developmental years of 15–21.
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
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
Comparative Study on Physical Fitness of Volleyball and Football Players in U...iosrjce
Background: Physical fitness is an essential first and foremost criterion in every game. Without having physical
fitness no one can elicit his amble performance level. Therefore it is essential to investigate that in which game
among Volleyball and Football, the level of physical fitness is more essential. Aim: The purpose of this study
was to investigate the level of physical fitness of volleyball player and football player in university level.
Methodology: For the present study 15 male volleyball players and 15 male football players were selected
randomly and they had participated in university competition in 2004 from Jadavpur University. Age group of
the subjects was 18-24 years. To find out the physical fitness APHERED Youth Physical Fitness Test were
conducted. Statistics: For comparison of various physical fitness components of volley ball players and football
player independent t-test has done and level of significance has verified at 0.05 levels. Result: Finding reveals
that muscular strength of football player (5.33 times/min. pull ups) was higher than volley ball player (4.87
times/min. pull ups), the muscular endurance of football player (39.86 times sit ups) was higher than volleyball
player (38.73 times sit ups), agility of football player (19.32 sec.) was higher than volleyball player (19.78 sec.),
explosive leg strength of football player (6.90 mts.) was higher than volleyball player (6.78 mts.), Speed of
football player (6.70 sec.) was higher than volley ball player (6.99 sec.) and also cardiovascular endurance of
football player (1.82 min.) was higher than volleyball player (1.82 min.) but the difference in agility and speed
were significant at 0.05 level. Conclusion: The physical fitness of football player was higher than the volleyball
player.
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.
Training the vertical jump to head the ball in soccer Fernando Farias
IN MODERN SOCCER, HEADING
THE BALL IS BOTH AN OFFENSIVE
TOOL USED TO SCORE GOALS
AND A DEFENSIVE MEASURE
AGAINST OPPOSING TEAMS. PRO-
FICIENCY IN HEADING THE BALL
REQUIRES PROPER TECHNIQUE IN
CONJUNCTION WITH AN EFFEC-
TIVE VERTICAL JUMP. THE AIM OF
THIS ARTICLE IS TO ADDRESS THE
FACTORS INVOLVED IN VERTICAL
JUMP PERFORMANCE AND HOW
THEY RELATE SPECIFICALLY TO
HEADING THE BALL
Bibliografia articolo La periodizzazione nell’allenamento della forza rapida” di Klaus Wirth, Dietmar Schmidtbleicher. SDS Scuola dello Sport, 74
http://www.calzetti-mariucci.it/shop/prodotti/sds-rivista-di-cultura-sportiva-numero-arretrato-74
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
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.
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.
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.
Does strength training change your movement patterns?Fernando Farias
Most of us in this industry believe that good movement patterns make someone
a better athlete, as well making them less likely to get injured. Unsurprisingly,
therefore, a lot of programs have been put together to help you improve your
movement patterns.
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.
Muscular strength, functional performances and injury risk in professional an...Fernando Farias
Muscle strength and anaerobic power of the lower extre-
mities are neuromuscular variables that influence perfor-
mance in many sports activities, including soccer. Despite
frequent contradictions in the literature, it may be assumed
that muscle strength and balance play a key role in targeted
acute muscle injuries. The purpose of the present study was
to provide and compare pre-season muscular strength and
power profiles in professional and junior elite soccer players
throughout the developmental years of 15–21.
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
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
Comparative Study on Physical Fitness of Volleyball and Football Players in U...iosrjce
Background: Physical fitness is an essential first and foremost criterion in every game. Without having physical
fitness no one can elicit his amble performance level. Therefore it is essential to investigate that in which game
among Volleyball and Football, the level of physical fitness is more essential. Aim: The purpose of this study
was to investigate the level of physical fitness of volleyball player and football player in university level.
Methodology: For the present study 15 male volleyball players and 15 male football players were selected
randomly and they had participated in university competition in 2004 from Jadavpur University. Age group of
the subjects was 18-24 years. To find out the physical fitness APHERED Youth Physical Fitness Test were
conducted. Statistics: For comparison of various physical fitness components of volley ball players and football
player independent t-test has done and level of significance has verified at 0.05 levels. Result: Finding reveals
that muscular strength of football player (5.33 times/min. pull ups) was higher than volley ball player (4.87
times/min. pull ups), the muscular endurance of football player (39.86 times sit ups) was higher than volleyball
player (38.73 times sit ups), agility of football player (19.32 sec.) was higher than volleyball player (19.78 sec.),
explosive leg strength of football player (6.90 mts.) was higher than volleyball player (6.78 mts.), Speed of
football player (6.70 sec.) was higher than volley ball player (6.99 sec.) and also cardiovascular endurance of
football player (1.82 min.) was higher than volleyball player (1.82 min.) but the difference in agility and speed
were significant at 0.05 level. Conclusion: The physical fitness of football player was higher than the volleyball
player.
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.
Training the vertical jump to head the ball in soccer Fernando Farias
IN MODERN SOCCER, HEADING
THE BALL IS BOTH AN OFFENSIVE
TOOL USED TO SCORE GOALS
AND A DEFENSIVE MEASURE
AGAINST OPPOSING TEAMS. PRO-
FICIENCY IN HEADING THE BALL
REQUIRES PROPER TECHNIQUE IN
CONJUNCTION WITH AN EFFEC-
TIVE VERTICAL JUMP. THE AIM OF
THIS ARTICLE IS TO ADDRESS THE
FACTORS INVOLVED IN VERTICAL
JUMP PERFORMANCE AND HOW
THEY RELATE SPECIFICALLY TO
HEADING THE BALL
Bibliografia articolo La periodizzazione nell’allenamento della forza rapida” di Klaus Wirth, Dietmar Schmidtbleicher. SDS Scuola dello Sport, 74
http://www.calzetti-mariucci.it/shop/prodotti/sds-rivista-di-cultura-sportiva-numero-arretrato-74
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
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.
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.
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
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.
High intensity warm ups elicit superior performance Fernando Farias
The benefits of an active warm-up (WU) have been
attributed to increases in muscle temperature, nerve
conductivity, and the speeding of metabolic reactions.1 Non-
temperature-related benefifis include an increased blood-flflw
to working muscles, elevated baseline oxygen consumption,
and the induction of a post-activation potentiation (PAP)
effect.
1. POSTER TEMPLATE BY:
www.PosterPresentations.com
SOUTHWESTM I N N E S O T A S T A T E U N I V E R S I T Y
The Effects of Post-Activation Potentiation Using Maximum Isometric Contractions on College Football Players ,
Alex Oliver, Blake Pennock & Jeffrey W. Bell
Southwest Minnesota State University 1501 State Street Marshall, MN 56258
Results/Discussion Conclusion
References
Introduction
Abstract Methods
Acknowledgement
1. Sale, D.G. (2002). Postactivation Potentiation: Role in
Human Performance. Exercise in sport science reviews,
Vol. 30, Issue (3): 138-143.
2. Babajic, F., Bradic, A., Klino, A., Kovanecevic, E. Effects
of Maximum Isometric Contraction on Explosive Power
of Lower Limbs (Jump Performance). Sport SPA, Vol. 7,
Issue (1): 69-75.
Post-Activation Potentiation allows for the
potentiation of the neuromuscular system which may
improve power and performance of the athlete.
A common theory for this improvement of power and
performance is the concept of myosin light chain
phosphorylation. Myosin light chain phosphorylation
causes the actin-myosin interaction to be more
sensitive when releasing the calcium ion from the
sarcoplasmic reticulum, thus allowing for faster
muscle twitch and contractions (Sale, 2002).
PAP research has used dynamic contractions, but
few studies have investigated the effects of static
isometric contractions to potentiate muscular power
(Babajic, 2010).
The primary goal of our research was to determine
whether maximal voluntary isometric contractions
improve performance and power.
Post-Activation Potentiation (PAP) has been reported to
increase force production through activating
neuromuscular systems. PAP is typically performed by
contracting skeletal muscle near maximum force
development. The objective of this investigation is to
determine if PAP using maximum voluntary isometric
contractions (MVC) influences instantaneous peak-power
output and performance in vertical jump and back squat.
In two separate sessions, twelve collegiate football
players performed either a dynamic warm-up or a dynamic
warm-up followed by a six second MVC before each test.
Vertical jump was similar with and without PAP (72.0±6.9
vs 72.8±7.2 vs cm, p=0.76). Back squat peak-power was
greater, but not significantly different, with PAP compared
to without (1864±315 vs. 1725±281 Watts, p=0.26) as
was instantaneous peak-power during vertical jump
(2528±390 vs. 2241±330 Watts, p=0.11. Additional
subject recruitment and testing is needed to determine
whether isometric PAP influences instantaneous peak
power but does not appear to improve vertical jump
height.
Participants
Ethical approval received from SMSU’s IRB and
participants were provided written informed consent.
12 collegiate football players participated.
Subject characteristics: age (20.8±1.37 years),
weight (93.3±9.68 kg), and height (185.7±3.98 cm).
Study Design
This study was performed in two sessions with each
session being a week apart.
Session 1 included a dynamic warm-up followed by
testing.
Session 2 included a dynamic warm-up and PAP
followed by testing. PAP was performed 30. seconds
before vertical jump tests and back squat tests.
Testing included a vertical jump and back squat.
Procedures
Vertical Jump- While standing on a vertical jump mat
(Just Jump) and connected to a power analyzer
(Tendo), subjects completed three trials of a maximal
jump for height.
Back Squat- The power analyzer (Tendo) was
connected to the barbell and configured to the weight
being lifted. Subjects performed three trials of 1
repetition at 50% of 1 Repetition Maximum as rapidly
as they could lift the weight.
Activation was performed by using the barbell to
push against the power rack in the back squat position.
The power rack was adjusted for about 90 degrees of
knee flexion for the isometric contraction position. The
subjects were then instructed and encouraged as they
pushed up against the power rack for six-seconds
(Figure 1B).
Thank you to those who volunteered as subjects for our
research, Dr. Jeffrey W. Bell for assisting us throughout our
study, and Caleb Heim for providing us with support and
data documentation that was used for the subjects’ one-
repetition maximums.
Vertical jump height was similar in both
conditions.
The mean vertical jump peak power was
12.8% better when the testing was
conducted following isometric contraction
activation, but did not reach significance.
The mean back squat peak power was 8%
higher when the testing was conducted
following isometric contraction activation, but
did not reach significance.
Table 2A: The mean results obtained for the combined subjects for each
testing activity with and without activation.
Figure 1C: Comparison of mean peak power in the
vertical jump test among all subjects with activation
(2527.97 ± 389.6) and without activation (2240.65 ±
330.25).
Figure 1B: A photograph of the activation method used
to potentiate the individual’s neuromuscular system
prior to testing.
Maximum voluntary isometric contractions
may not effectively potentiate the
neuromuscular system and improve peak
power and performance.
Results of this study suggest only small,
non-significant improvements in peak power.
The study may have been underpowered
and additional recruitment and testing is
needed.
The power analyzer did not capture data for
vertical jump of three subjects and
contributed to the lack of study power.
Future studies should perform PAP prior to
each and every trial as previous trials may
moderate performance.
Recovery time increments may need to be
varied to determine the effect on potentiation
to ensure fatigue was not inhibiting
performance.
The joint angle of the maximum voluntary
isometric contractions may also be altered in
further research to determine the most
effective angle to properly potentiate the
neuromuscular system for each performance
task.
Overall, this study allowed us to gain insight
on the possibility of maximum voluntary
isometric contractions ability to potentiate
the neuromuscular system and will allow for
improvements during follow-up studies.
Warm-Up Exercise Distance
Warm-Up Jog 200 yards
Walking Knee up & Grab 15 yards
Walking Single Leg Toe Touch 15 yards
Walking Ankle Grab 15 yards
High Knee Run 20 yards
Butt-Kick Run 20 yards
Carioca (high knee over) 20 yards each way
High Knee Skip 20 yards
Figure 1A: The dynamic warm-up exercises and distances that were performed prior to each
session.
Test Without Activation With Activation
Vertical Jump Height (cm) 72.83 (± 7.16) 71.96 (± 6.82)
Vertical Jump Peak Power
(Watts)
2240.64 (± 330.25) 2527.97 (± 389.6)
Back Squat Peak Power
(Watts)
1725.4 (± 282) 1864 (± 314.6)
Figure 1D: Comparison of mean peak power in
the Back Squat test among all subjects with
activation(1864 ± 314.6) and without
activation(1725.4 ± 282).