Repeated-Sprint Training With Blood-Flow Restriction Improves Repeated-Sprint Ability Similarly to Unrestricted Training at Reduced External Loads.

PURPOSE: This study examined performance and physiological adaptations following 3 weeks of repeated-sprint training (RST) with blood-flow restriction (BFR) or without (non-BFR). METHODS: Twenty-six semiprofessional and amateur adult male team-sport players were assessed for repeated-sprint ability, anaerobic capacity, leg lean mass, neuromuscular function, and maximal aerobic capacity before and after RST. Participants completed 9 cycling RST sessions (3 sets of 5-7 × 5-s sprints, 25-s passive recovery, 3-min rest) over a 3-week period with BFR or non-BFR. RESULTS: During RST sessions, the BFR group demonstrated lower mean power output compared with non-BFR (-14.5%; g = 1.48; P = .001). Significant improvements (P < .05) in mean and peak power output during repeated-sprint ability (+4.1%; g = 0.42, and + 2.2%; g = 0.25, respectively) and anaerobic capacity (+4.8%; g = 0.47, and + 4.7%; g = 0.32, respectively) tests, leg lean mass (+2.0%; g = 0.16), and peak aerobic power (+3.3%; g = 0.25) were observed from pretesting to posttesting without any between-groups differences. No significant changes (P > .05) were observed for maximal isometric voluntary contraction and maximal aerobic capacity. Peak rate of force development decreased (P = .003) in both groups following RST (-14.6%; g = 0.65), without any between-groups differences. CONCLUSIONS: Repeated-sprint ability, anaerobic capacity, leg lean mass, and peak aerobic power improved following 3 weeks of RST; however, the addition of BFR did not further enhance adaptations. Interestingly, comparable improvements were achieved between groups despite lower external loads experienced during RST sessions with BFR.

Can changes in resistance exercise workload influence internal load, countermovement jump performance and the endocrine response?

This study examined the influence of differing volume load and intensity (%1 repetition maximum[%1RM]) resistance exercise workouts on session rating of perceived exertion (sRPE) countermovement jump (CMJ) performance and endocrine responses. Twelve participants performed a workout comprising four exercises (bench press, back squat, deadlift and prone bench pull) in randomised order as either power (POW); 3 sets × 6 repetitions at 45%1RM × 3 min inter-set rest, strength (ST); 3 sets × 3 repetitions at 90%1RM × 3 min inter-set rest, or hypertrophy (HYP); 3 sets × 10 repetitions at 70%1RM × 1 min inter-set rest in a randomised-crossover design. CMJ performance and endocrine responses were measured immediately pre-, post-, 12, 24, 48 and 72 h post-exercise. POW sRPE (3.0 ± 1.0) was lower than ST (4.5 ± 1.0) (P = 0.01), and both were lower than HYP (8.5 ± 1.0) (P = 0.01). Duration of CMJ decrement was longer (P ≤ 0.05) for HYP (72 h) compared to POW (12 h) and ST (24 h). Testosterone concentration was greater (P ≤ 0.05) immediately post-exercise in HYP compared to POW and ST. In conclusion, less inter-set rest, greater volume load and intensity (%1RM) may increase sRPE, duration of CMJ performance decrement and testosterone responses in resistance exercise.

Muscle activation, blood lactate, and perceived exertion responses to changing resistance training programming variables.

Ratings of perceived exertion (RPE: 0-10) during resistance training with varying programming demands were examined. Blood lactate (BLa) and muscle activation (using surface electromyography: EMG) were measured as potential mediators of RPE responses. Participants performed three sets of single arm (preferred side) bicep curls at 70% of 1 repetition maximum over 4 trials: Trial (A) 3 sets × 8 repetitions × 120 s recovery between sets; (B) 3 sets × 8 repetitions × 240 s recovery; (C) 3 sets × maximum number of repetitions (MNR) × 120 s recovery; (D) 3 sets × MNR × 240 s recovery. Overall body (RPE-O) and active muscle (RPE-AM) perceptual responses were assessed following each set in each trial. Biceps brachii and brachioradialis muscle EMG was measured during each set for each trial. RPE-O and RPE-AM were not different between Trial A (3.5 ± 1 and 6 ± 1, respectively) and Trial B (3.5 ± 1 and 5.5 ± 1, respectively) (p < .05). However, RPE-AM was significantly greater in Trial C (7.5 ± 1.5) and Trial D (7.5 ± 1.5) than in Trial B (p < .05). There were no significant differences in muscle activation or BLa between trials; however, work rate (tonnage/min) was greater in Trials C and D compared to Trial B. In conclusion, BLa and muscle activation were not related to RPE, but resistance training variables, such as work rate, may impact on RPE when intensity (%1RM) and the number of sets completed remain constant.

A comparative analysis of accelerometer and time-motion data in elite men's hockey training and competition.

PURPOSE: To determine the relationship between distance covered and player load (PL: sum of accelerations in all 3 planes of movement) in hockey training and competition. METHODS: Elite male hockey players (N=24) wore player-tracking devices in 7 international matches and 7 training sessions. Players were arranged in 4 positional groups (strikers, attacking midfielders, defensive midfielders, defenders) in competition but had generic roles in training. Relationships between distance and PL were assessed in both absolute (m, AU) and relative (m/min, AU/min) terms and were compared between matches and training and between positions within matches, using the Fisher Z test. RESULTS: In competition, the absolute distance-PL relationship was very large overall (r=.868), with no differences between positions. The relative distance-PL relationship was moderate overall (r=.486) and weaker in strikers than in defensive midfielders (Z=1.785, P=.037) and defenders (Z=1.690, P=.045). In training, the absolute distance-PL relationship was very large (r=.742), and large (r=.633) in relative terms. The relationship was stronger in competition than training for absolute values (Z=2.824, P=.005) but not different for relative values. CONCLUSIONS: The strong relationship between these variables suggests that PL in hockey is mostly accumulated through running and other locomotor actions, such that PL is not effective in quantifying other activities (evasion, low stance) that contribute to physiological demands, particularly in training.

Perceived exertion responses to changing resistance training programming variables.

This study examined the influence of intensity (%1 repetition maximum [1RM]), tonnage (sets × repetitions × load), rate of fatigue (percentage decrement in repetitions from set to set), work rate (total tonnage per unit of time), rest interval (time between sets), time under load, and session duration on session rating of perceived exertion (sRPE: Borg's CR-10 scale). Here, participants performed a standardized lifting session of 5 exercises (bench press, leg press, lat pulldown, leg curl, and triceps pushdown) as either: (a) 3 sets × 8 repetitions × 3-minute recovery at 70% 1RM, (b) 3 sets × 14 repetitions × 3-minute recovery at 40% 1RM, (c) 3 sets × MNR (maximum number of repetitions) × 1-minute recovery at 70% 1RM, (d) 3 sets × MNR × 3-minute recovery at 70% 1RM, (e) 3 sets × MNR × 1-minute recovery at 40% 1RM, or (f) 3 sets × MNR × 3-minute recovery at 40% 1RM. The sRPE for session A (4 ± 1) was significantly higher than session B (2.5 ± 1), despite matched tonnage. Protocols involving MNR showed no significant difference in sRPE. Work rate was the only variable to significantly relate with sRPE (r = 0.45). Additionally, sRPE at 15-minute postexercise (5 ± 2) was not different to 30-minute postexercise (5 ± 2). In resistance training with matched tonnage and rest duration between sets, sRPE increases with intensity. In sets to volitional failure, sRPE is likely to be similar, regardless of intensity or rest duration between sets.