ArticlePDF AvailableLiterature Review

Abstract

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 provide 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 significant increases in sprint acceleration performance, thus highlighting the importance of movement pattern and contraction velocity specificity. Relatively large gains in power output in nonspecific 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 specificity 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. Hypertrophy and general power exercises can enhance sports performance, but optimal transfer from training also requires a specific exercise program.
74
The author is with the School of Human Movement and Sport Sciences, University of Ballarat, Bal-
larat, Victoria 3353 Australia.
BRIEF REVIEWS
International Journal of Sports Physiology and Performance, 2006;1:74-83
© 2006 Human Kinetics, Inc.
Transfer of Strength and Power Training
to Sports Performance
Warren B. Young
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.
Key Words: resistance training, sprinting performance, neuromuscular factors,
specifi city, plyometrics
The ability to generate relatively high forces against large resistances (strength)
and to produce a high work rate (power) is important for various sports. As such,
resistance training has become an integral component of the physical preparation
for enhancement of sports performance, and strength and conditioning training has
become a specialization within sports training. A key issue for athletes and coaches
at all levels is effi ciency of training, that is, achieving the greatest gains in perfor-
mance for a given amount of work effort. Therefore, the concept of maximizing
the transfer of training to performance is paramount.
Transfer may be conceptually expressed as being a function of the following:
gain in performance/gain in trained exercise (modifi ed from Zatsiorsky1). For
example, using the data of Wilson et al,2 8 weeks of strength training with the squat
exercise produced a 21% gain in the one-repetition-maximum (1RM) squat. This
Transfer of Strength and Power Training 75
change was accompanied by an improvement in vertical-jump (VJ) performance
of 21% and 40-m sprint performance of 2.3%. This example shows that training
to improve leg strength as measured by a 1RM squat has excellent transference
to VJ performance but considerably less to sprinting performance. Key issues
involve determining the factors responsible for attaining high levels of transfer
and whether appropriate training guidelines have been identifi ed. This article will
address these issues.
Central to the concept of transfer is the well-accepted training principle of
specifi city, which states that adaptations are specifi c to the nature of the train-
ing stress. If this principle is followed to the extreme, all training would simply
mimic competition demands. Although such an approach may be expected to yield
a good transfer to performance in the short term and in experienced athletes, it
might also be expected to produce negative outcomes such as overtraining, muscle
imbalances, increased injury risk, and boredom in the long term.3 If only specifi c
training were used by athletes, many popular resistance-training modalities would
never be used.
Approximately 60 years ago, coaches acknowledged that there was a role for
general or nonspecifi c training to provide a “foundation” of fi tness.4 More recently,
general training has come to be thought valuable because it allows the development
of a balanced neuromuscular system and serves as a base from which to train more
specifi cally at later stages.3 Beginner athletes can achieve good transfer from general
training, whereas experienced athletes attain specifi c adaptations.1,5 This suggests
that the principle of specifi city of training becomes more relevant according to the
levels of training experience and performance.6
The remainder of this review will examine previous research to understand
the transfer of strength and power training to sports performance, discuss a physi-
ological basis for transfer, and suggest training implications. It is beyond the scope
of this article to explore all aspects of sports performance, so I will use sprinting,
which is a fundamental component of many sports, as an example.
Sprinting
Considerable research has indicated signifi cant correlations between sprinting
performance over various distances and a range of measures of strength7-10 and
power.8-12 Signifi cant relationships between strength and power and sprint perfor-
mance imply that the muscle function assessed by strength and power tests has some
commonality with performance. This might suggest that improvement in strength
and power may lead to improvement in sprint performance, but because correlation
does not indicate cause and effect, it is necessary to examine longitudinal studies
involving resistance-training programs.
Sprint performance can be considered to contain 3 independent components:
acceleration, maximum speed, and speed maintenance.13 Statistical analysis of
100-m sprint running has confi rmed this classifi cation.14 Squats and jump squats
(JS, loaded vertical jumps) are popular exercises for training strength and power,
respectively, and have also been used in training studies. High-resistance weight
training of the leg-extensor muscles is effective for improving maximum strength
in a squat test, but this has not transferred to sprint speed.15-16 For example, Harris
et al16 reported that 9 weeks of training with various squat and pulling exercises
76 Young
produced an approximately 10% gain in squat strength, but this was associated
with no change in 30-m sprint performance. One study2 was able to demonstrate
statistically signifi cant gains in 40-m sprint performance after 8 weeks of squat
training. To achieve a 2.2% gain in sprint performance, however, a 21% improve-
ment in squat strength was required.
Although sprint performance may be more related to power than to strength,
similar fi ndings have been reported for power training. Training with either JS or
plyometric exercise has been shown to produce signifi cant gains in jump tests of leg
power with small and nonsignifi cant changes in sprint performance.15-18 Experienced
male sprinters who trained with various weight-training machines that involved hip
and knee extensors and fl exors were able to improve their 1RM squat by 12.4%.19
The corresponding improvements in acceleration and maximum speed, however,
were only 4.3% and 1.9%, respectively. One study15 required subjects to perform
JS with the load that yielded maximum power output over a 10-week period. The
mean improvement in JS height using a 4-kg bar was 16.8%, but this was associated
with only a 1.1% change in 30-m sprint time. In all of these studies,15-18 the power
training consisted of exercises involving VJ performed bilaterally.
The poor transfer of power training could relate to a lack of movement specifi c-
ity to sprinting, which involves unilateral contractions of the leg extensors resulting
in total body movement in a horizontal direction. This suggestion is consistent
with the fi ndings of Rimmer and Sleivert,20 who reported that 8 weeks of plyo-
metric training including some unilateral/horizontal exercises induced signifi cant
improvements (2.6%) in sprint time to 10 m. Furthermore, a 9-week sprint and
plyometric program including both unilateral and horizontal exercises improved
sprint performance to 10 m signifi cantly more than sprinting alone, and, interest-
ingly, the improved 10-m performance did carry over to 100-m performance.14 In
these plyometric training studies,14,20 however, the benefi ts to short sprints did not
extend to maximum speed.
The ability of some plyometric exercises to transfer to sprinting might par-
tially refl ect the contraction velocity specifi city. Bounding exercises have been
found to possess ground-contact times very similar to those of the acceleration
phase of sprinting.21-22 In contrast, even low-resistance JS involve push-off times
that are relatively long, such as >0.7 second.15 This point is worthy of elaboration.
The rationale for using relatively light loads in resistance exercises is to produce a
combination of contraction force and movement velocity that approximates maxi-
mum power output.15-16 Cronin et al23 conducted a study with nonresistance-trained
females who performed bench-press throws with 60% of the predicted 1RM for 6
weeks. This load is considered “light” because in untrained women, 20 bench-press
repetitions can be performed with this load.24 Bench-press throws with 60% of 1RM
allowed a mean bar velocity of 0.4 m/s to be generated.23 When the same subjects
executed a maximum-effort netball pass, the average ball speed generated was 11.4
m/s.23 In this example, the “light load/high speed” resistance exercise produced a
movement speed representing only 3.5% of the speed attained in the netball pass.
This shortcoming highlights the diffi culty of achieving sport-specifi c movement
velocities with many resistance-training exercises.
Alternatives to exercises such as JS or bench-press throws with barbells are
plyometric exercise (discussed above) and the performance of the sport skill with
added load. An example of the latter is sprinting while pulling a loaded sled. A study
Transfer of Strength and Power Training 77
that compared unresisted and sled-resisted sprinting25 indicated that a sled load of
12.5% of body mass produced a running velocity that was 90% of the unresisted
velocity over 15 m. The authors concluded that this load would be suitable for train-
ing because it produced minimal disruption to sprint mechanics but still provided the
necessary overload. Furthermore, it appears that achieving movement and velocity
specifi city is easier with this mode of resistance training. A recent study26 evaluated
the effects of sled sprint training with a 5-kg load (about 7% of body mass) on sprint
performance. Eight repetitions of 20- to 50-m sprints performed over an 8-week
period produced a signifi cant 2.0% gain in running velocity over the fi rst 20 m,
but no improvement in maximum speed was attained. These fi ndings are expected
because sprinting mechanics using a sled are more similar to the acceleration phase
(eg, more forward lean) than the maximum-speed phase of sprinting.26
Resisted sports movements such as sled sprinting could potentially hinder
sports performance if the skill is dramatically changed. This concern is probably
unfounded for 2 reasons. First, the greater the additional load used in sled sprinting,
the greater the modifi cation to the unresisted sport skill.25,27 Therefore, the use of a
relatively light load, such as the 12.5% of body mass recommended by Lockie et
al,25 should ensure minimal alteration of the correct mechanics. Second, the volume
of this type of resistance training would be far less than the quantity of unresisted
sprint training, which would further minimize any expected biomechanical disrup-
tion over time. Nevertheless, more longitudinal research concerning the potential
benefi ts of many resisted-sprinting methods is needed.
Physiological Basis of Transfer
Strength and power production in sport are infl uenced by a range of neuromuscular
factors. In simple terms, muscle performance is determined by a combination of
muscle cross-sectional area and the extent to which the muscle mass is activated,
that is, neural factors.28-30 Sprinting is infl uenced by neuromuscular function, and,
because of its complexity, many different muscles must be activated at the appro-
priate times and intensities to maximize speed.13
Because muscle cross-sectional area is related to voluntary strength,31 hypertro-
phy training methods potentially increase force and power output in a sports move-
ment. With regard to enhancing sports performance, an important consideration
with hypertrophy training is the concept of optimum muscle and total body mass.
Gains in muscle size are associated with gains in body mass, and such changes may
or may not enhance sports performance, depending on the needs of the individual.
For example, hypertrophy methods might be appropriate for a shot-putter seeking
gains in absolute strength and power, but they could reduce the power:weight ratio
of a high jumper and therefore inhibit high-jump performance.32
According to Carroll et al,33 the physiological adaptations associated with
resistance training can potentially produce either positive or negative transfer to
sports performance. Negative transfer could occur if there is increased coactivation
of antagonist muscles because this would produce force that opposes the intended
movement direction.28 For example, Baratta et al34 showed that knee-fl exion training
produced greater knee-fl exion activation during a knee-extension strength test. This
observation indicates that the training of the hamstrings caused this muscle group to
78 Young
produce greater antagonistic coactivation during the knee-extension task. Positive
transfer can occur if resistance training reinforces the optimum muscle-activation
patterns that are required in the execution of the sport skill.33 This could be achieved
by either increased excitatory neural activation of muscles that contribute to skill-
ful performance and/or by inhibition of muscles that can degrade performance.33
Apart from decreased cocontraction of antagonists, transfer might be enhanced by
improved interaction between synergists.30 Generally, the improved coordination of
muscles involved in a sports movement has been termed intermuscular coordina-
tion35 and is considered important for sprint performance.13
The importance of intermuscular coordination for achieving transfer from
training to athletic performance is demonstrated by 2 studies involving different
methodologies. In the fi rst study, Bobbert and Van Soest36 used a computer simula-
tion of VJ performance from input of force produced over time by 6 lower extremity
muscles. First, the model was optimized to maximize jump height using parameters
similar to those recorded from well-trained volleyball players. When only muscle
force was increased to simulate increased muscle strength, it was found that jump
height decreased. For example, a 20% increase in knee-extensor force in isolation
produced a 9-cm decrease in jump height. When the model was reoptimized using
this enhanced muscle force, jump height was improved by 3 cm beyond the original
performance. This fi nding indicates that jump performance could be impaired by
altered intermuscular coordination, despite increased force output from individual
muscles. The authors concluded that to improve jumping performance, a precise
tuning of the control of muscle properties must be achieved.
The second study37 required subjects to perform 3 sets of 10 repetitions of
an isokinetic knee-extension and -fl exion exercise at 100°/s for 6 weeks. After 6
weeks of training each leg unilaterally, the mean gain in quadriceps and hamstrings
isokinetic strength assessed at the training velocity was between 7% and 11.8% and
was statistically signifi cant for the quadriceps. Improvements in standing long-jump
performance were more modest (2.3%) and not signifi cant, despite the fact that this
activity signifi cantly involves the quadriceps and hamstring muscles. Because the
subjects in this study did not practice jumping during the training period, it could
be speculated that the intermuscular coordination was not optimal and may have
limited the transfer from the training. The relatively poor transfer might also be
explained by a violation of the specifi city principle. Sale and MacDougall38 sug-
gested that training should be specifi c in terms of movement pattern, contraction
velocity, contraction type, and contraction force. The training exercise differed
from the standing long jump with regard to all of these factors.
Intermuscular coordination refers to the interaction between muscles that
control a movement, but neural adaptations confi ned to a single muscle might
also explain performance enhancement from training and have thus been termed
intramuscular coordination.35 These include such factors as increased motor-unit
recruitment, fi ring rates, and synchronization, as well as refl ex potentiation30,35 and
decreased inhibition from eccentric loads during stretch–shorten cycle contractions
to optimize musculotendinous stiffness.39
Although the measurement of these individual mechanisms is complex,
changes in neural activation as recorded by surface electromyography (EMG)
have been clearly demonstrated in resistance-training studies.18,29,40 Yet despite
signifi cant gains in the neural activation of individual muscles, transfer to specifi c
Transfer of Strength and Power Training 79
sports movements can be limited. For example, McBride et al18 reported that
subjects who trained for 8 weeks with JS using 80% of their 1RM squat achieved
an increase of greater than 60% in the average EMG output of the vastus lateralis
while performing JS. This was accompanied by a smaller 10% gain (statistically
signifi cant) in peak power output while jumping and no improvement in jump
height or sprinting performance. This fi nding indicates that intramuscular coor-
dination factors might be relatively less infl uential than intermuscular factors
and reinforces the importance of movement-pattern specifi city for transfer to
jumping and sprinting performance.
The Role of General Resistance Training
The specifi city of resistance training for transfer to sports performance has been
highlighted. Therefore, what is the role, if any, for general or nonspecifi c resistance
training? First, general strength training has been shown to transfer to performance
in skills such as VJ5 and baseball-throwing velocity.41 For example, strength train-
ing using bench-press and pull-over exercises for 8 weeks produced a 22.8% gain
in 6RM strength, and this was accompanied by a signifi cant improvement (4.1%)
of baseball-throwing velocity.42 The subjects in this study had a mean age of 18.6
years and no previous experience in resistance training. It is not clear whether
similar gains could occur from general strength training in highly strength-trained
baseball players.
Another proposed benefi t of general strength training is a reduction in the
risk of sports injuries such as damage to soft tissues. As such, a signifi cant por-
tion of an athlete’s time in physical preparation might be devoted to this goal. For
example, eccentric strength training for the hamstrings has been recommended for
the prevention and rehabilitation from hamstring strains43 and has been shown to be
effective for injury reduction using a prospective randomized controlled research
design.44 General strength training of the muscles of the lower extremity has also
been shown to be just as effective45 or more effective46 than balance training for
enhancing balance and proprioception. Because balance capabilities have been
linked to sports-injury risk,47 strength training might have a prophylactic benefi t.
The development of core stability has also become a focus of many strength
and conditioning programs, especially in junior athletes.48 Core stability is thought
to be important for sprint-running effi ciency.49 Research using a prospective design50
indicated that hip-abduction and external-rotation strength were signifi cantly lower
in athletes who were subsequently injured during a season and led the authors to
conclude that core stability has an important role in injury prevention. However, 6
weeks of core-stability training in recreational athletes has been shown to enhance
measures of core stability, without signifi cant transfer to running economy or
performance.51
Although a strong connection between core-stability training and injury
prevention is yet to be established by researchers, 2 key issues for strength and
conditioning professionals have emerged. The fi rst is determining the proportion
of the program devoted to injury prevention and general training compared with
specifi c training designed to maximize transfer to sports performance directly. The
second is the appropriate ways in which to develop core stability, as there is a large
range of exercise possibilities.52
80 Young
Conclusions and Practical Applications
General strength training might be benefi cial for athletes because of the potential
to enhance the force-generating capabilities of muscle, increase total body mass,
reduce the risk of sports injuries, and improve core stability. However, direct transfer
to improve sports performance might be limited by such training in experienced
athletes. Although nonspecifi c resistance training can induce neural adaptations
and increase the power production of individual muscles, it appears that to maxi-
mize transfer to specifi c sports skills, training should be as specifi c as possible,
especially with regard to movement pattern and contraction velocity. This type of
training can be expected to enhance intermuscular coordination and ensure that
muscles are “tuned” to any newly acquired force-generating capacity. Adding a
load to a sports movement would seem to be a suitable strategy to achieve this
specifi city, although the amount and direction of added resistance would need to
be considered. The potential benefi t of resisted sports movements such as sprinting
requires further research.
Ultimately, a combination of general and specifi c resistance-training methods
can be recommended to develop all the neuromuscular factors contributing to
sports skills requiring strength and power.23,41,53 The way in which these methods
are integrated over time is an issue of periodization that must be considered3 and is
likely to depend on the needs and developmental level of the individual athlete. A
developing athlete might be advised to emphasize core stability, muscle hypertrophy
(if increased body mass is advantageous), and intramuscular coordination. Provided
a solid foundation has been developed, a highly resistance-trained athlete might be
expected to benefi t more from training intermuscular coordination.
It may be useful to think of training an athlete to improve sprinting perfor-
mance by using an analogy of a competitive sports car (Table 1). General training
Table 1 Strategies for Developing Power in a Sprinter Based on
Neuromuscular Factors Using an Analogy of a Race Car
Race-car
performance Sprinting
performance
Example of
neuromuscular
factors Training methods
engine capacity muscle cross-
sectional area muscle cross-
sectional area
Hypertrophy with
squats
engine power
output, eg, opti-
mum timing of all
cylinders
intramuscular
coordination of
involved muscles
motor-unit
recruitment, fi ring
rates, synchroniza-
tion, refl ex poten-
tiation
Jump squats
with load that
maximizes power
output
conversion of
power from engine
to road, eg, effec-
tive transmission
intermuscular
coordination activation of
synergists,
cocontraction of
antagonists
Resisted sprints,
unilateral/horizon-
tal plyometrics, eg,
speed bounding
Transfer of Strength and Power Training 81
may include hypertrophy to increase the force-generation capacities of important
muscles, as well as strengthening core muscles (not shown). The second training
strategy is to develop the “neural activation capacity” of the relevant muscles.
Although these combined approaches might build a powerful athlete, maximization
of transfer to sports performance requires the “conversion” of powerful muscles
to a coordinated sports skill.
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... The use of UL training has been found to be an effective training method to increase muscle strength and performance 4 . Advantages with UL training include improvements in balance and stability as core and stabilizing musculature are recruited when one limb or one side of the body is trained at a time, addressing muscle imbalances between contralateral sides of the body by addressing weaknesses or discrepancies, and aiding in enhancements of functional fitness or sport-specific movements as many real-life activities of daily living and sport-specific movements rely on the use of one limb or side of the body at a time 5,6 . ...
... The use of BL training has been demonstrated to be an effective training method to increase muscle strength and performance 10 . Advantages with BL training may include the ability to lift heavier loads as both limbs or both sides of the body are being used to move the resistive load, more efficient training sessions due to both limbs or sides of the body working concurrently, and better muscle synergy with multiple muscle groups engaged at the same time 4,11,12 . ...
... Faster sprint performance can provide a significant advantage in both team and individual sports (4,23,56). Although numerous training methods have been shown to improve sprint performance (3,63), the principle of specificity suggests that incorporating external resistance or assistance into sprinting may enhance sprint performance more effectively (1,58,85). Consequently, resisted sprint training (RST) and assisted sprint training (AST) are widely used in practice. These methods enhance an athlete's ability to produce greater force and power while maintaining sprint-specific mechanical characteristics, such as movement patterns and contraction types (1,26,58,78). ...
... These methods enhance an athlete's ability to produce greater force and power while maintaining sprint-specific mechanical characteristics, such as movement patterns and contraction types (1,26,58,78). This specificity and transference have the potential to enhance acute sprint performance through a process known as postactivation performance enhancement (PAPE) (17,85). ...
Article
The aim of the meta-analysis was to determine the acute effects of resisted (RST), assisted (AST), and unresisted (UST) sprint training on sprint performance and to identify the optimal training protocol. A computerized search was conducted in five databases, resulting in the inclusion of 23 studies and 395 participants. The findings indicated that RST acutely improved sprint performance (effect size [ES] -0.20; p < 0.05), while UST (ES = -0.03) and AST (ES = -0.18) did not produce significant improvements (p > 0.05). Subgroup analyses revealed that RST load as a percentage of body mass (%BM) showed the greatest improvement with heavy loads (50-75% BM, ES = -0.40) compared to light (0-19% BM, ES = -0.22), moderate (20-49% BM, ES = -0.21), and very heavy (>75% BM, ES = 0.10) loads. Further analyses indicated that sled pushing (ES = -0.60) was more effective than sled pulling (ES = -0.34) under heavy load RST conditions. Nonlinear meta-regression results demonstrated that sprint performance improvement exhibited an inverted-U relationship with RST load. Additionally, heavy load RST and moderate load AST did not disrupt subsequent sprinting technique. In conclusion, only RST acutely improved subsequent sprint performance, whereas AST and UST did not. For optimal results with RST, it is recommended to use one set of heavy loads (50-75% BM) for sled pushing over a distance of 15-20 meters, followed by a rest period of 4-8 minutes before performing 0-30 meters of UST.
... A significant body of research has supported the relationship between sprint performance and measurements of strength and power in numerous sports, suggesting that muscle function has some association with sprint performance [1]. Swimming is characterized by unique demands on muscle function, taking place in a singular environment where water viscosity increases resistance to movement. ...
... A strength test has been defined as a procedure to determine the ability to generate high forces against large resistances, whereas a power test has been understood as the assessments to determine the ability to produce a high work rate [1]. Hence, for the present study, those tests which aim to obtain maximum strength would be considered as strength tests, whereas those tests aiming to obtain the maximum strength at a maximum rate or speed, including actions involving the activation of the stretch-shortening cycle (explosive countermovement jumps, drop jumps or short sprints), would be considered as power tests. ...
Article
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Purpose To determine the association between lower-body strength and lower-body power capacities with sprint swimming performance in adolescent competitive swimmers. Methods A total of 44 front crawl swimmers (27 males and 17 females) performed anthropometric assessments, lower-body strength tests (half squat maximum isometric strength, dynamic half squat with 20, 30 and 40 % of the maximum isometric strength, and knee extension maximum isometric strength) and lower-body power tests (squat jump [SJ], countermovement jump [CMJ] and Abalakov jump). Further front crawl swimming best times in 50 and 100 m were recorded from official swimming competitions and front crawl technique was assessed by an experienced coach using a visual analogue scale. Results Swimming performance was correlated with lower-body power variables (SJ [r=−0.573 for 50 m and −0.642 for 100 m], CMJ [r=−0.497 for 50 m and −0.544 for 100 m], and Abalakov jump [r=−0.452 for 50 m and −0.415 for 100 m]; p≤0.05) and lower-body strength (half squat maximum isometric strength [r=−0.430 for 50 m and −0.443 for 100 m]; p≤0.05) in males but not in females. Further linear regression models showed that only lower-body power predicted both 50 m (Abalakov jump; r²=0.58; change in r²=0.18) and 100 m (SJ; r²=0.66; change in r²=0.15) performance in male swimmers. Conclusions This study emphasizes the greater association between lower-body power and sprint front crawl performance in adolescent males compared to females. Practical tests (i.e., SJ and Abalakov jump) are shown to predict front crawl swimming performance, which may facilitate the performance control by coaches and trainers.
... Among the factors contributing to sports success, athletes typically gain an advantage over their opponents by possessing greater muscular strength and power, as well as favorable body morphology and composition [1][2][3][4]. Higher strength and power levels often translate into greater speed, jump height and a reduced risk of injury [4][5][6]. Muscular power and speed are critical components of physical fitness in various track and field events [1]. Additionally, muscle quantity, size, and qualityoften assessed through imaging techniques-are linked to performance [3,7,8]. ...
Article
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Background Raw data obtained through bioelectrical impedance analysis (BIA) have been applied in different populations to assess body fluids and cell integrity. Assessing raw BIA parameters in specific muscles is an emerging method for evaluating muscle function. We investigated the associations of the BIA-derived variables of resistance (R), reactance (Xc) and phase angle (PhA) measured through whole-body (WB) and muscle-localized (ML) methods with performance in the countermovement jump (CMJ) and 50-meter (m) sprint. Methods Thirty-one male track and field athletes (16.5 ± 1.6 years) were assessed. Fat-free mass (FFM) and Fat mass percentage (%FM) were determined by skinfold thickness. BIA at 50 kHz was employed to obtain the WB and ML (right thigh) parameters. The WB and ML-BIA parameters were adjusted by height (R/H, Xc/H) and segment length (R/L, Xc/L). The CMJ assessment was conducted via a contact mat; the software recorded the jump height. The 50-m sprint time was measured via two sets of photocells. Pearson’s correlation and linear multiple regression were performed. Results ML-PhA was inversely related to the 50-m sprint (β=-0.56) and by itself explained 29% of the sprint time variation. It remained a significant predictor even after adjusting for age, height, FFM and peak height velocity (PHV). ML-R/L was directly related to 50-m sprint (β = 0.48) and inversely related to CMJ performance (β=-0.54), explaining 20% and 27% of the variation in 50-m sprint and CMJ performance, respectively. Similarly, it remained a significant predictor in the adjusted models. Correlations between WB-BIA (PhA, R/H) and performance tests were found to be dependent on covariates. Conclusions In this sample, the ML-BIA parameters of R/L and PhA were significantly associated with performance independent of age, height, FFM and PHV. Higher ML-PhA values were associated with better sprint times, whereas higher ML-R/L values were associated with worse sprint times and CMJ performance.
... This is due to the important association observed between the maximum strength (i.e., 1RM) of the lower-limb measured through this exercise and performance in different sports actions such as vertical and horizontal jump, linear sprint, change of direction, repeated sprint ability, tackling proficiency (21)(22)(23)(24)(25)(26)(27)(28), the injury incidence (29), and competitioninduced muscle damage (30). Notably, exclusive utilization of full or deep squat exercises during RT yields favorable outcomes in enhancing jumping, sprinting, the ability to repeat sprints, and kicking ball speed (15,17,(31)(32)(33)(34)(35)(36), which means that this exercise produces a high degree of transfer to sporting actions (37,38). ...
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Background: The squat exercise has been shown to improve athletic performance. However, the use of the deep squat has been questioned due to claims that it may cause knee joint injuries. Therefore, the purpose of this scoping review was to synthesize existing literature concerning the impact of deep squats on knee osteoarticular health in resistance-trained individuals. Methods: This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines. The original protocol was prospectively registered in Figshare (https://doi.org/10.6084/m9.figshare.24945033.v1). A systematic and exhaustive search was conducted in different databases: PubMed, Scopus, Web of Science, and SPORTDiscus. Additional searches were performed in Google Scholar and PEDro. The main inclusion criteria were the following: (1) Articles of experimental, observational, or theoretical nature, including randomized controlled trials, longitudinal studies, case reports, integrative reviews, systematic reviews, and meta-analyses(Primary studies were required to have a minimum follow-up duration of 6 weeks, whereas secondary studies were expected to adhere to PRISMA or COCHRANE guidelines or be registered with PROSPERO; (2) Peer-reviewed articles published between 2000 and 2024; (3) Publications written in English, Spanish and Portuguese; (4) Studies reporting the effects of deep half, parallel or quarter squats on the knee or evaluating squats as a predictor of injury. Results: The keyword search resulted in 2,274 studies, out of which 15 met all inclusion criteria. These 15 studies comprised 5 cohort studies, 3 randomized controlled trials, 4 literature or narrative reviews, 1 case study, and 2 systematic reviews, one including a meta-analysis. Overall, the risk of bias (ROB) across these studies was generally low. It is worth noting that only one study, a case study, associated deep squats with an increased risk of injury, the remaining 14 studies showed no negative impact of deep squats on knee joint health. Conclusion: The deep squat appears to be a safe exercise for knee joint health and could be included in resistance training programs without risk, provided that proper technique is maintained. https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2024.1477796/full?utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field&journalName=Frontiers_in_Sports_and_Active_Living&id=1477796
... Movements in weightlifting largely involve performance-based physical features such as speed, strength and power (Hori et al., 2005). Very high force production and the capacity to perform a task as quickly as possible can often be counted as supporting qualities of sports skills such as jumping, sprinting, changing direction and weightlifting (Young 2006, Suchomel et al., 2016. Therefore, the main purpose of training programs is to improve strength, power, agility and speed, as well as to achieve the maximum possible sports performance (Morris et al., 2022). ...
... Sporcuların, maks mum, patlayıcı veya reakt f kuvvet özell kler n gel ştreb lmek ç n düzenl olarak antrenman programlarını uygulamaları gerekl d r. Bu programlar, kas ç koord nasyonun yanı sıra, sürekli olarak geliştirilmelidir (Young, 2006). Sporcuların performanslarını zlemek, antrenman sürec n n başarısı ç n kr t k b r faktördür. ...
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The combination of small-sided games and jump training exercises is widely used to improve various performance factors in athletes. This study is a research conducted on young amateur female volleyball players to determine which performance characteristics are enhanced by combining small-sided games with jump rope and plyometric training in volleyball, as well as to examine whether jump rope training can be an alternative to plyometric training. A total of 16 volunteer athletes participated in the study, with 8 participants assigned to the jump rope group and 8 participants assigned to the plyometric training group. Before the study, all participants' pre-test values for speed, agility, balance, vertical jump, reactive strength index, hamstring/quadriceps ratio, isokinetic knee joint measurements (at 60°s⁻¹ and 180°s⁻¹), and ankle strength (at 30°s⁻¹ and 120°s⁻¹) were determined through the necessary measurements. Both groups participated in small-sided games twice a week. The first group engaged in jump rope training in addition to smallsided games for 4 weeks, twice a week. The second group participated in plyometric training during the same duration and schedule. Following the 4-week period, all participants' aforementioned values were re-evaluated through post-test measurements. Due to the normal distribution of all variables, a mixed ANOVA test was conducted. When comparing the initial and final test measurements of all participants, significant improvements were observed in speed, agility, balance, vertical jump, hamstring/quadriceps ratio, and some isokinetic strength data, except for the reactive strength index (p<0.05). Upon examining the measurements between groups, it was found that the effect on performance values among participants was significantly different across all measurement parameters (p<0.05). In conclusion, jump rope and plyometric training contributed positively to certain performance factors of the participants, albeit to varying degrees. Based on the obtained results, jump rope training has been identified as an alternative to plyometric training.
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The aim of this study was to quantify the training effects of wearing calf‐loaded wearable resistance (WR) during a netball specific warm‐up in female netball athletes. Twenty‐nine high school female netball athletes were matched for change of direction (COD) speed and randomly allocated to either WR training or an unloaded group. Both groups performed the same warm‐up two times per week for 6 weeks, with the WR group wearing 1%–1.5% body mass loads on each calf. Pre‐ and post‐training data were collected for 5‐ and 15‐m sprint times, modified 5‐0‐5 COD splits and total time and single‐leg horizontal, lateral and countermovement (CMJ) jump performance. Both groups significantly decreased their 5 m linear sprint times (WRT = −4.41%, effect size [ES] = −1.60; control [CON] = −2.60%, ES = −0.71), while only the WRT significantly decreased their 15 m time (−2.14%, ES = −1.55). There were no significant decreases in 5‐0‐5 total time for either group, however the WRT group significantly decreased their acceleration (−7.40%, ES = −0.60) and COD split (−9.73%, ES = −1.02). Both groups increased their lateral jump (WRT: 4.60%–6.62%, ES = 0.67–0.96; CON: 5.48%–6.06%, ES = 0.73–0.75), while only the WRT group increased (p < 0.05) their horizontal jump (3.57%–4.18%, ES = 0.57–0.67). Given the results, it appears that calf‐loaded WR may be an effective method for improving linear speed, aspects of the modified 5‐0‐5 test and horizontal jump ability in female netball athletes.
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Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field-sport athletes. Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of body mass. Stride length was significantly reduced by similar to10 and similar to24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. In addition, sled towing increased ground contact time, trunk lean, and hip flexion. Upper-body results showed an increase in shoulder range of motion with added resistance. The heavier load generally resulted in a greater disruption to normal acceleration kinematics compared with the lighter load. The lighter load is likely best for use in a training program.
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Performance in sprint exercise is determined by the ability to accelerate, the magnitude of maximal velocity and the ability to maintain velocity against the onset of fatigue. These factors are strongly influenced by metabolic and anthropometric components. Improved temporal sequencing of muscle activation and/or improved fast twitch fibre recruitment may contribute to superior sprint performance. Speed of impulse transmission along the motor axon may also have implications on sprint performance. Nerve conduction velocity (NCV) has been shown to increase in response to a period of sprint training. However, it is difficult to determine if increased NCV is likely to contribute to improved sprint performance. An increase in motoneuron excitability, as measured by the Hoffman reflex (H-reflex), has been reported to produce a more powerful muscular contraction, hence maximising motoneuron excitability would be expected to benefit sprint performance. Motoneuron excitability can be raised acutely by an appropriate stimulus with obvious implications for sprint performance. However, at rest H-reflex has been reported to be lower in athletes trained for explosive events compared with endurance-trained athletes. This may be caused by the relatively high, fast twitch fibre percentage and the consequent high activation thresholds of such motor units in power-trained populations. In contrast, stretch reflexes appear to be enhanced in sprint athletes possibly because of increased muscle spindle sensitivity as a result of sprint training. With muscle in a contracted state, however, there is evidence to suggest greater reflex potentiation among both sprint and resistance-trained populations compared with controls. Again this may be indicative of the predominant types of motor units in these populations, but may also mean an enhanced reflex contribution to force production during running in sprint-trained athletes. Fatigue of neural origin both during and following sprint exercise has implications with respect to optimising training frequency and volume. Research suggests athletes are unable to maintain maximal firing frequencies for the full duration of, for example, a 100m sprint. Fatigue after a single training session may also have a neural manifestation with some athletes unable to voluntarily fully activate muscle or experiencing stretch reflex inhibition after heavy training. This may occur in conjunction with muscle damage. Research investigating the neural influences on sprint performance is limited. Further longitudinal research is necessary to improve our understanding of neural factors that contribute to training-induced improvements in sprint performance.
Article
Objectives To determine whether proprioception or muscular strength is the dominant factor in balance and joint stability and define what type of ankle rehabilitation is most effective for these purposes. Setting The University of North Carolina Sports Medicine Research Laboratory. Subjects Thirty-two healthy volunteers free of head injury, dominant leg injury, and vestibular deficits. Design Subjects were divided into control, strength-training, proprioceptive-training, and strength-proprioception combination training groups. Balance was assessed before and after 6-week training programs. Measurements Static, semidynamic, and dynamic balance were assessed. Results Subjects showed no improvement for static balance but improved significantly for semidynamic ( P = .038) and dynamic (P = .002) balance. No significant differences were observed between groups. Conclusions Enhancement of proprioception and muscular strength are equally effective in promoting joint stability and balance maintenance. In addition, no 1 type of training program is superior to another for these purposes.
Article
This study was undertaken to compare force-time characteristics, muscle power, and electromyographic (EMG) activities of the leg muscles in maximal sprinting and in selected bounding and jumping exercises. Seven male sprinters performed maximal bounding (MB), maximal stepping (MS), maximal hopping with the right (MHR) and left (MHL) legs, and maximal sprint running (MR). These “horizontal” exercises and running were performed on a force platform. EMG activity was telemetered unilaterally from five leg muscles during each trial. The results indicated significant ( p < .001) differences among the studied exercises in velocity, stride length, stride rate, flight time, and contact time. Also, significant differences were noticed in reactive forces ( p < .01-.001) and power ( p < .01) among the performances, whereas only insignificant differences were observed in EMG patterns. The average resultant forces during the braking and propulsion phases in MS, MHR, and MHL were greater ( p < .001) than in MR and MB. Stepping and hopping are cyclic and sprint-specific and may be used as strength exercises for sprinters because of great strength demand.
Article
It has long been believed that resistance training is accompanied by changes within the nervous system that play an important role in the development of strength. Many elements of the nervous system exhibit the potential for adaptation in response to resistance training, including supraspinal centres, descending neural tracts, spinal circuitry and the motor end plate connections between motoneurons and muscle fibres. Yet the specific sites of adaptation along the neuraxis have seldom been identified experimentally, and much of the evidence for neural adaptations following resistance training remains indirect. As a consequence of this current lack of knowledge, there exists uncertainty regarding the manner in which resistance training impacts upon the control and execution of functional movements. We aim to demonstrate that resistance training is likely to cause adaptations to many neural elements that are involved in the control of movement, and is therefore likely to affect movement execution during a wide range of tasks. We review a small number of experiments that provide evidence that resistance training affects the way in which muscles that have been engaged during training are recruited during related movement tasks. The concepts addressed in this article represent an important new approach to research on the effects of resistance training. They are also of considerable practical importance, since most individuals perform resistance training in the expectation that it will enhance their performance in related functional tasks.