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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 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.

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Conall F. Murtagh, Christopher Nulty, Jos Vanrenterghem, Andrew O’Boyle, Ryland Morgans, Barry Drust, and Robert M. Erskine

independent lower-limb power qualities in soccer players. 3 However, no attempt has been made to investigate the neuromuscular factors underpinning direction-specific (soccer associated) CMJ performance. Such information could be used to inform the neuromuscular factors that should be considered when

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Ashley Stern, Chris Kuenze, Daniel Herman, Lindsay D. Sauer, and Joseph M. Hart

Context:

Central and peripheral muscle fatigue during exercise may exacerbate neuromuscular factors that increase risk for noncontact anterior cruciate ligament injury.

Objective:

To compare lower extremity motor-evoked potentials (MEPs), muscle strength, and electromyography (EMG) activation after an exercise protocol.

Design:

Pretest, posttest group comparison.

Setting:

University laboratory.

Participants:

34 healthy volunteers (17 female, age = 21.9 ± 2.3 years, weight = 77.8 ± 3.0 kg, height = 171.1 ± 6.6 cm, and 17 male, age = 23.4 ± 6.5 years, weight = 81.6 ± 3.3 kg, height = 179.6 ± 7.3 cm).

Intervention:

A standardized 30-min exercise protocol that involved 5 repeated cycles of uphill walking, body-weight squatting, and step-ups.

Main Outcome Measures:

Quadriceps and hamstring MEP amplitude (mV) and transmission velocity normalized to subject height (m/s) were elicited via transcranial magnetic stimulation and measured via surface EMG. Quadriceps and hamstring peak EMG activation (% MVIC) and peak torque (Nm/kg) were measured during MVICs. Separate ANCOVAs were used to compare groups after exercise while controlling for baseline measurement.

Results:

At baseline, males exhibited significantly greater knee-extension torques (males = 2.47 ± 0.68 Nm/kg, females = 1.95 ± 0.53 Nm/kg; P = .036) and significantly higher hamstring MEP amplitudes (males = 223.5 ± 134.0 mV, females = 89.3 ± 77.6 mV; P = .007). Males exhibited greater quadriceps MEP amplitude after exercise than females (males = 127.2 ± 112.7 mV, females = 32.3 ± 34.9 mV; P = .016).

Conclusions:

Males experienced greater peripheral neuromuscular changes manifested as more pronounced reductions in quadriceps torque after exercise. Females experienced greater central neuromuscular changes manifested as more pronounced reduction in quadriceps MEP amplitude. Reduced central neural drive of the quadriceps coupled with knee-extension torque preservation after exercise may increase risk of knee injury in females.

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Kris Beattie, Brian P. Carson, Mark Lyons, and Ian C. Kenny

Cycling economy (CE), power output at maximal oxygen uptake (WV̇O2max), and anaerobic function (ie, sprinting ability) are considered the best physiological performance indicators in elite road cyclists. In addition to cardiovascular function, these physiological indicators are partly dictated by neuromuscular factors. One technique to improve neuromuscular function in athletes is through strength training. The aim of this study was to investigate the effect of a 20-wk maximal- and explosive-strength-training intervention on strength (maximal strength, explosive strength, and bike-specific explosive strength), WV̇O2max, CE, and body composition (body mass, fat and lean mass) in cyclists. Fifteen competitive road cyclists were divided into an intervention group (endurance training and strength training: n = 6; age, 38.0 ± 10.2 y; weight, 69.1 ± 3.6 kg; height, 1.77 ± 0.04 m) and a control group (endurance training only: n = 9; age, 34.8 ± 8.5 y; weight, 72.5 ± 7.2 kg; height, 1.78 ± 0.05 m). The intervention group strength-trained for 20 wk. Each participant completed 3 assessments: physiology (CE, WV̇O2max, power at 2 and 4 mmol/L blood lactate), strength (isometric midthigh pull, squat-jump height, and 6-s bike-sprint peak power), and body composition (body mass, fat mass, overall leanness, and leg leanness). The results showed significant between- and within-group changes in the intervention group for maximal strength, bike-specific explosive strength, absolute WV̇O2max, body mass, overall leanness, and leg leanness at wk 20 (P < .05). The control group showed no significant within-group changes in measures of strength, physiology, or body composition. This study demonstrates that 20 wk of strength training can significantly improve maximal strength, bike-specific explosive strength, and absolute WV̇O2max in competitive road cyclists.

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Daniel Boullosa

some algorithms to predict middle- and long-distance running performance, with an error <3%, which included some jumping evaluations, apart from the classic aerobic tests. This was before the first studies on the influence of neuromuscular factors on endurance running by Paavolainen et al. 6 , 7

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Daniel Boullosa, César C.C. Abad, Valter P. Reis, Victor Fernandes, Claudio Castilho, Luis Candido, Alessandro M. Zagatto, Lucas A. Pereira, and Irineu Loturco

hip thrusts, 14 or their combination) may further improve jumping and running performances. The use of multistage running evaluations 15 for better understanding the effect of PAP protocols on neuromuscular factors and pacing is also recommended. References 1. Boullosa D , Del Rosso S , Behm

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Nicola Marotta, Andrea Demeco, Gerardo de Scorpio, Angelo Indino, Teresa Iona, and Antonio Ammendolia

The knee is one part of a kinetic chain and anatomic sites other than the knee including the trunk, hip, and ankle may contribute to ACL injuries. 4 Neuromuscular factors are significant and may be the most important reason for the increased risk of ACL injuries in women. 5 Ahmad et al 6

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Nicholas Tam, Ross Tucker, Jordan Santos-Concejero, Danielle Prins, and Robert P. Lamberts

GRF resultant vector and the leg axis during stance, leg stiffness, and stride angles did show good relationships with running economy. 13 , 14 In addition to these biomechanical features, certain neuromuscular factors controlling movement initiation and regulation, such as muscle activation during

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Grégoire P. Millet, Rosalie Trigueira, Frédéric Meyer, and Marcel Lemire

was to investigate if a 3-week LHTH camp induces acute changes in running mechanics in middle-distance runners. We aimed to test the hypothesis that LHTH would lead to an alteration in biomechanical and neuromuscular factors associated to force production 6 and consequently to a deterioration of

Open access

Christopher Kevin Wong, Lizbeth Conway, Grant Fleming, Caitlin Gopie, Dara Liebeskind, and Stephen Xue

muscle weakness. 7 , 11 The longevity of the observed strength increases was not determined in any of the 3 included studies. Any observed strength increases related to potential musculoskeletal or neuromuscular factors contributing to the treatment effects may be short-lived, and future investigations