Blood Flow Restriction Attenuates Muscle Damage in Resistance Exercise Performed Until Concentric Muscle Failure.

The present study aimed to evaluate whether blood flow restriction (BFR) can prevent exercise-induced muscle damage in resistance exercise (RE) performed until concentric muscle failure (CMF). Twenty healthy volunteers (25 ± 4 years, 80.4 ± 11.8 kg, 175 ± 8 cm) performed three sets of unilateral biceps curl exercise (40% of 1RM) with (RE + BFR) and without (RE) BFR until CMF. A third condition was to perform the same number of repetitions as RE + BFR without using BFR (matched). Performing fewer repetitions, RE + BFR caused muscle fatigue post-exercise as high as that caused by RE. In addition, the range of motion, upper arm circumference, pressure pain threshold, and maximal voluntary contraction were immediately affected by our exercise protocol with BFR, returning rapidly to basal values within 24 h, while in RE, muscle damage markers remained elevated until 48 h post-exercise. The same results were observed concerning serum creatine kinase and lactate dehydrogenase activity. Thus, BFR + RE performed until CMF attenuated muscle damage following similar metabolic stress to RE alone performed until CMF, with less work volume.

The Effects of Physical Fitness on Postactivation Potentiation in Professional Soccer Athletes.

ABSTRACT: Guerra, MA Jr, Caldas, LA, Souza, HL, Tallis, J, Duncan, MJ, and Guimarães-Ferreira, L. The effects of physical fitness on postactivation potentiation in professional soccer athletes. J Strength Cond Res 36(6): 1643-1647, 2022-To investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response.

The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players.

BACKGROUND: Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance. METHODS: Twelve male professional soccer players (23 ± 5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg- 1) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively). RESULTS: Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11] = 14.99, P < 0.001, partial η2 = 0.577). Analysis also indicated a significant difference in CMJ performance across conditions, with caffeine eliciting a greater response (F[1, 11] = 10.12, P = 0.009, partial η2 = 0.479). CMJ height was increased at T1, T3 and T5 in caffeine condition (5.07%, 5.75% and 5.40%, respectively; P < 0.01) compared to baseline. In the placebo condition, jump performance was increased at T3 (4.94%; P < 0.01) only. Jump height was higher in caffeine condition on T1, T3 and T5 (P < 0.05) but not on baseline (P > 0.05) compared to placebo. CONCLUSIONS: The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players.

Blood flow restriction attenuates eccentric exercise-induced muscle damage without perceptual and cardiovascular overload.

The aim of this study was to evaluate the acute effects of high-intensity eccentric exercise (HI-ECC) combined with blood flow restriction (BFR) on muscle damage markers, and perceptual and cardiovascular responses. Nine healthy men (26 ± 1 years, BMI 24 ± 1 kg m- ²) underwent unilateral elbow extension in two conditions: without (HI-ECC) and with BFR (HI-ECC+BFR). The HI-ECC protocol corresponded to three sets of 10 repetitions with 130% of maximal strength (1RM). The ratings of perceived exertion (RPE) and pain (RPP) were measured after each set. Muscle damage was evaluated by range of motion (ROM), upper arm circumference (CIR) and muscle soreness using a visual analogue scale at different moments (pre-exercise, immediately after, 24 and 48 h postexercise). Systolic (SBP), diastolic (DBP), mean blood pressure (MBP) and heart rate (HR) were measured before exercise and after each set. RPP was higher in HI-ECC+BFR than in HI-ECC after each set. Range of motion decreased postexercise in both conditions; however, in HI-ECC+BFR group, it returned to pre-exercise condition earlier (post-24 h) than HI-ECC (post-48 h). CIR increased only in HI-ECC, while no difference was observed in HI-ECC+BFR condition. Regarding cardiovascular responses, MBP and SBP did not change at any moment. HR showed similar increases in both conditions during exercise while DBP decreased only in HI-ECC condition. Thus, BFR attenuated HI-ECC-induced muscle damage and there was no increase in cardiovascular responses.