Acute effects of whole body vibration combined with blood restriction on electromyography amplitude and hormonal responses.

The purpose of this study was to investigate the effects of whole body vibration (WBV) exercise with and without blood flow restriction (BFR) on electromyography (EMG) amplitude and hormonal responses. Eight healthy male adults who lacked physical activity participated in this study and completed 10 sets of WBV and WBV + BFR sessions in a repeated measures crossover design. In the WBV + BFR session, the participants wore a BFR device inflated to 140 mmHg around the proximal region of the thigh muscles. The results indicated that the EMG values from the rectus femoris and vastus lateralis during the WBV + BFR session were significantly higher than those during the WBV session (p < 0.05). Two-way analysis of variance with repeated measures showed that the WBV + BFR and WBV exercise sessions induced a significant (simple main effect for time) increase in lactate (LA) (0.61-4.68 vs. 0.46-3.44 mmol/L) and growth hormone (GH) (0.48-3.85 vs. 0.47-0.82 ng/mL) responses after some of the post-exercise time points (p < 0.05). WBV + BFR elicited significantly higher LA and GH (simple main effect for trial) responses than did WBV after exercise (p < 0.05). Although no significant time × trial interactions were observed for testosterone (T) (604.5-677.75 vs. 545.75-593.88 ng/dL), main effects for trial (p < 0.05) and for time (p < 0.05) were observed. In conclusion, WBV + BFR produced an additive effect of exercise on EMG amplitude and LA and GH responses, but it did not further induce T responses compared to those with WBV alone.

Foot Cooling between Interval Bouts Enhances Repeated Lower Limb Power Performance: The Role of Delaying Fatigue.

This study aimed to investigate whether interbout foot cooling (FC) may enhance repeated lower limb power performance and the corresponding physiological responses based on interset FC, which has been demonstrated to enhance leg-press performance. In a repeated-measures crossover design, ten active men (aged 21.5 ± 1.5 years, exercising >3 times per week) performed four bouts of 10-s cycle ergometer sprints with interbout FC at 10°C water for 2.5 min or non-cooling (NC) with a 5-day interval. The results indicated that FC elicited higher total work (27.57 ± 5.66 kJ vs. 26.55 ± 5.76 kJ) and arousal scores than NC (p < 0.05). Furthermore, under the NC condition, participants decreased mean power (p < 0.05) with no alteration of vastus lateralis (VL) electromyography (EMG) activities after the second bout; whereas under the FC condition, participants maintained steady mean power accompanied by increased VL EMG activities in the last two bouts (p < 0.05). Jointly, participants had higher mean power ([3rd = 10.14 ± 1.15 vs. 9.37 ± 1.30; 4th = 9.79 ± 1.22 vs. 9.23 ± 1.27] W/kg) and VL EMG activities in the last two bouts under the FC than NC condition (p < 0.05). However, perceived exertion and the heart rate were comparable between the two conditions (p > 0.05). In conclusion, interbout FC elicited a higher arousal level and repeated lower limb power performance, which could be explained by delaying peripheral fatigue via increasing excitatory drive and recruiting additional motor units to compensate for fatigue-related responses and power decrements.

Effect of Acute Interset Foot Cooling on Lower Limb Strength Training Workout.

PURPOSE: The authors investigated the effect of foot cooling (FC) between sets in a leg press pyramid workout with resistance-trained participants. METHODS: A total of 12 resistance-trained men (age = 21.8 [0.6] y; training experience = 1.7 [1] y) performed a pyramid workout, including 4 sets of 85% to 90% 1-repetition maximum leg press exercise to exhaustion with interset FC or noncooling in a repeated-measures crossover design separated by 5 days. The authors immersed the participants' feet in 10°C water for 2.5 minutes between sets. RESULTS: Two-way repeated-measures analysis of variance revealed that FC elicited significantly higher repetitions and electromyography (EMG) values of the vastus lateralis (simple main effect of condition) than did noncooling (P < .05) in the second (repetitions: 11 [3.5] vs 7.75 [3.2]; EMG: 63.4% [19.4%] vs 54.5% [18.4%]), third (repetitions: 8.9 [3.2] vs 6.4 [2.1]; EMG: 71.5% [17.4%] vs 60.6% [19.4%]), and fourth (repetitions: 7.5 [2.7] vs 5.1 [2.2]; EMG: 75.2% [19.6%] vs 59.3% [23.5%]) sets. The authors also detected a simple main effect of set in the FC and noncooling conditions on repetitions (P < .05) and in the FC condition on the vastus lateralis EMG values. Although the authors observed no time × trial interactions for the rating of perceived exertion, the authors observed main effects on the sets (7.7-9.6 vs 7.9-9.3, P < .05). CONCLUSIONS: Interset FC provides an ergogenic effect on a leg press pyramid workout and may offset fatigue, as indicated by higher repetitions and EMG response, without increasing perceived exertion.

Effects of whole body vibration training combined with blood flow restriction on muscle adaptation.

AbstractThis study investigated the effects of whole body vibration (WBV) training combined with blood flow restriction (BFR) on muscle fitness. Twenty physically inactive adults were randomly assigned to a WBV + BFR group (8 men and 2 women) and a WBV group (8 men and 2 women). The participants in the WBV group were subjected to 10 sets of intermittent WBV exercise 20 min/day, 3 days/week, for 8 weeks. The participants in the WBV + BFR group received the same WBV treatment, but the proximal portion of their thighs was compressed using inflatable cuffs. Dual-energy X-ray absorptiometry estimated thigh muscle mass, one repetition maximal (1RM) leg press, and muscle endurance were measured before and after the training programme. The results indicated that thigh muscle mass significantly increased (3%) after the 8-week training period only in the WBV + BFR group. Meanwhile, 1RM leg press and muscle endurance significantly increased in both groups after training (p < 0.05). Analysis of covariance revealed that the increase in 1RM leg press and muscle endurance was significantly higher (p < 0.05) in the WBV + BFR group than the WBV group (leg press: 11.1%. vs. 4.37%; muscle endurance: 48.84% vs. 15.19%, respectively). In conclusion, exposure to regular WBV + BFR training can increase thigh muscle mass, maximal strength, and muscle endurance compared with exposure to WBV training alone. WBV + BFR training appears to be a feasible strategy for improving muscle mass, strength, and endurance in previously untrained participants.

Acute Effects of Intermittent Foot Cooling on 1 RM Leg Press Strength in Resistance-Trained Men: A Pilot Study.

Inter-set peripheral cooling can improve high-intensity resistance exercise performance. However, whether foot cooling (FC) would increase 1 repetition maximum (RM) lower-limb strength is unclear. This study investigated the effect of intermittent FC on 1 RM leg press strength. Ten recreational male lifters performed three attempts of 1 RM leg press with FC or non-cooling (NC) in a repeated-measures crossover design separated by 5 days. FC was applied by foot immersion in 10 °C water for 2.5 min before each attempt. During the 1 RM test, various physiological measures were recorded. The results showed that FC elicited higher 1 RM leg press strength (Δ [95% CI]; Cohen's d effect size [ES]; 13.6 [7.6-19.5] kg; ES = 1.631) and electromyography values in vastus lateralis (57.7 [8.1-107.4] µV; ES = 0.831) and gastrocnemius (15.1 [-3.1-33.2] µV; ES = 0.593) than in NC. Higher arousal levels (felt arousal scale) were found in FC (0.6 [0.1-1.2]; ES = 0.457) than in NC. In conclusion, the preliminary findings, although limited, suggest intermittent FC has a potential ergogenic role for recreational athletes to enhance maximal lower-limb strength and may partly benefit strength-based competition events.