Full Range of Motion Induces Greater Muscle Damage Than Partial Range of Motion in Elbow Flexion Exercise With Free Weights.

Baroni, BM, Pompermayer, MG, Cini, A, Peruzzolo, AS, Radaelli, R, Brusco, CM, and Pinto, RS. Full range of motion induces greater muscle damage than partial range of motion in elbow flexion exercise with free weights. J Strength Cond Res 31(8): 2223-2230, 2017-Load and range of motion (ROM) applied in resistance training (RT) affect the muscle damage magnitude and the recovery time-course. Because exercises performed with partial ROM allow a higher load compared with those with full ROM, this study investigated the acute effect of a traditional RT exercise using full ROM or partial ROM on muscle damage markers. Fourteen healthy men performed 4 sets of 10 concentric-eccentric repetitions of unilateral elbow flexion on the Scott bench. Arms were randomly assigned to partial-ROM (50-100°) and full-ROM (0-130°) conditions, and load was determined as 80% of 1 repetition maximum (1RM) in the full- and partial-ROM tests. Muscle damage markers were assessed preexercise, immediately, and 24, 48, and 72 hours after exercise. Primary outcomes were peak torque, muscle soreness during palpation and elbow extension, arm circumference, and joint ROM. The load lifted in the partial-ROM condition (1RM = 19.1 ± 3.0 kg) was 40 ± 18% higher compared with the full-ROM condition (1RM = 13.7 ± 2.2 kg). Seventy-two hours after exercise, the full-ROM condition led to significant higher soreness sensation during elbow extension (1.3-4.1 cm vs. 1.0-1.9 cm) and smaller ROM values (97.5-106.1° vs. 103.6-115.7°). Peak torque, soreness from palpation, and arm circumference were statistically similar between conditions, although mean values in all time points of these outcomes have suggested more expressive muscle damage for the full-ROM condition. In conclusion, elbow flexion exercise with full ROM seems to induce greater muscle damage than partial-ROM exercises, even though higher absolute load was achieved with partial ROM.

Effects of acute dehydration on neuromuscular responses of exercised and nonexercised muscles after exercise in the heat.

Dehydration can impair aerobic performance, but its effects on muscular strength are still unclear. This study evaluated the effect of dehydration induced by cycling in the heat on exercised (knee extensors) and nonexercised (elbow flexors) muscles' strength and activation. Ten healthy recreationally active and nonacclimatized men (age, 22.71 ± 2.21 years old; body mass (BM), 77.94 ± 7.35 kg; height, 1.76 ± 6.46 m; body fat, 18.93 ± 3.01%) cycled in the heat in 2 separate sessions: dehydrated (DHY) and euhydrated (EUH). Dehydrated session led to a 2% BM loss, and water ingestion prevented the water loss in the euhydrated session. Knee extensor and elbow flexor maximal isometric torques and muscle activation were assessed before and after exercising in both sessions. Knee extensor torque decreased 15.8% (p < 0.001; 294.27 ± 44.82-247.16 ± 40.54) in dehydrated session, whereas no significant reduction (2.98%; p = 0.348; 291.99 ± 48.37-281.74 ± 38.65) was observed in the euhydrated session. No significant session-time interaction (p = 0.098) was observed for elbow flexor responses (DHY, 67.51 ± 14.53-62.95 ± 13.60; EUH, 68.26 ± 13.06-67.87 ± 13.89). Muscle activation capacity was unaffected by the hydration status. Maintenance of euhydration state during cycling in the heat may attenuate strength impairments caused by water loss in exercised muscle groups.