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Eric R. Helms, Caryn Zinn, David S. Rowlands and Scott R. Brown

Caloric restriction occurs when athletes attempt to reduce body fat or make weight. There is evidence that protein needs increase when athletes restrict calories or have low body fat.

Purpose:

The aims of this review were to evaluate the effects of dietary protein on body composition in energy-restricted resistance-trained athletes and to provide protein recommendations for these athletes.

Methods:

Database searches were performed from earliest record to July 2013 using the terms protein, and intake, or diet, and weight, or train, or restrict, or energy, or strength, and athlete. Studies (N = 6) needed to use adult (≥ 18 yrs), energy-restricted, resistance-trained (> 6 months) humans of lower body fat (males ≤ 23% and females ≤ 35%) performing resistance training. Protein intake, fat free mass (FFM) and body fat had to be reported.

Results:

Body fat percentage decreased (0.5–6.6%) in all study groups (N = 13) and FFM decreased (0.3–2.7kg) in nine of 13. Six groups gained, did not lose, or lost nonsignificant amounts of FFM. Five out of these six groups were among the highest in body fat, lowest in caloric restriction, or underwent novel resistance training stimuli. However, the one group that was not high in body fat that underwent substantial caloric restriction, without novel training stimuli, consumed the highest protein intake out of all the groups in this review (2.5–2.6g/kg).

Conclusions:

Protein needs for energy-restricted resistance-trained athletes are likely 2.3–3.1g/kg of FFM scaled upwards with severity of caloric restriction and leanness.

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Dustin J. Oranchuk, Eric J. Drinkwater, Riki S. Lindsay, Eric R. Helms, Eric T. Harbour and Adam G. Storey

Purpose: The power clean and other weightlifting movements are commonly used in the development of muscle power. However, there is a paucity of research examining the use of the hook grip (HG) in weightlifting performance. Therefore, the purpose of this study was to compare 1-repetition maximum (1RM) and kinetic, kinematic, and qualitative variables across a range of loads (75–100%) during power-clean performance with an HG and a closed grip. Methods: A total of 11 well-trained men (power-clean 1RM = 113.4 [15.9] kg, 1.34 × body mass) with at least 3 mo of HG experience volunteered to participate. Following a familiarization session, 1RM testing with the HG and closed grip were completed 5–7 d apart in a randomized order. Barbell kinetic and kinematic variables were recorded via a force platform and dual linear position transducer system. Results: All subjects had a greater 1RM with the HG than with the closed grip (P < .001, effect size [ES] = 0.43). Peak velocity (ES = 0.41–0.70), peak power (ES = 0.43–0.61), peak force (ES = 0.50–0.57), and catch height (ES = 0.40–0.96) were significantly greater (P < .05) when using the HG at all or most of the submaximal intensities. In addition, subjects reported significantly greater perceptions of grip security, power, and technical competency at submaximal but not maximal loads. Conclusions: Athletes and coaches who implement weightlifting movements in their physical preparation should adopt the HG where possible. Furthermore, researchers and sport scientists should control and report the grip type used when performing weightlifting-type movements.

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Scott R. Brown, Erin R. Feldman, Matt R. Cross, Eric R. Helms, Bruno Marrier, Pierre Samozino and Jean-Benoît Morin

The global application of horizontal force (F H) via hip extension is related to improvements in sprint performance (eg, maximal velocity [v max] and power [P max]). Little is known regarding the contribution of individual leg F H and how a difference between the legs (asymmetry) might subsequently affect sprint performance. The authors assessed a single male athlete for pre-post outcomes of a targeted hip-extension training program on F H asymmetry and sprint-performance metrics. An instrumented nonmotorized treadmill was used to obtain individual leg and global sprint kinetics and determine the athlete’s strong and weak leg, with regard to the ability to produce F H while sprinting. Following a 6-wk control block of testing, a 6-wk targeted training program was added to the athlete’s strength-training regimen, which aimed to strengthen the weak leg and improve hip-extension function during sprinting. Preintervention to postintervention, the athlete increased F H (standardized effect [ES] = 2.2; +26%) in his weak leg, decreased the F H asymmetry (ES = −0.64; −19%), and increased v max (ES = 0.67; +2%) and P max (ES = 3.2; +15%). This case study highlighted a promising link between a targeted training intervention to decrease asymmetry in F H and subsequent improvement of sprint-performance metrics. These findings also strengthen the theoretical relationship between the contribution of individual leg F H and global F H while sprinting, indicating that reducing asymmetry may decrease injury risk and increase practical performance measures. This case study may stimulate further research investigating targeted training interventions in the field of strength and conditioning and injury prevention.

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Eric R. Helms, Caryn Zinn, David S. Rowlands, Ruth Naidoo and John Cronin

Purpose:

Athletes risk performance and muscle loss when dieting. Strategies to prevent losses are unclear. This study examined the effects of two diets on anthropometrics, strength, and stress in athletes.

Methods:

This double-blind crossover pilot study began with 14 resistance-trained males (20-43 yr) and incurred one dropout. Participants followed carbohydrate-matched, high-protein low-fat (HPLF) or moderate-protein moderate-fat (MPMF) diets of 60% habitual calories for 2 weeks. Protein intakes were 2.8g/kg and 1.6g/kg and mean fat intakes were 15.4% and 36.5% of calories, respectively. Isometric midthigh pull (IMTP) and anthropometrics were measured at baseline and completion. The Daily Analysis of Life Demands of Athletes (DALdA) and Profile of Mood States (POMS) were completed daily. Outcomes were presented statistically as probability of clinical benefit, triviality, or harm with effect sizes (ES) and qualitative assessments.

Results:

Differences of effect between diets on IMTP and anthropometrics were likely or almost certainly trivial, respectively. Worse than normal scores on DALDA part A, part B and the part A “diet” item were likely more harmful (ES 0.32, 0.4 and 0.65, respectively) during MPMF than HPLF. The POMS fatigue score was likely more harmful (ES 0.37) and the POMS total mood disturbance score (TMDS) was possibly more harmful (ES 0.29) during MPMF than HPLF.

Conclusions:

For the 2 weeks observed, strength and anthropometric differences were minimal while stress, fatigue, and diet-dissatisfaction were higher during MPMF. A HPLF diet during short-term weight loss may be more effective at mitigating mood disturbance, fatigue, diet dissatisfaction, and stress than a MPMF diet.