This study examined the effects of anthocyanin-rich antioxidant juice (AJ) on the recovery of exercise-induced muscle damage (EIMD) and the running economy (RE) following downhill running (DHR). Thirty healthy young men were randomly divided into two blinded groups and consumed either AJ or placebo (PLA) for nine days (240 mL twice-a-day). On day 5, the participants from both groups ran downhill (−15%) for 30 min at 70% of their maximal oxygen uptake (VO₂max) speeds. The changes in RE (oxygen uptake (VO₂) and perceived effort (PE) during 5-min runs at 80%VO₂max) and EIMD (isometric peak torque (IPT), muscle soreness (SOR) and serum creatine kinase activity (CK)) were compared over time and between the groups on the 4 days following DHR. VO₂ and PE increased (p < 0.05) immediately following DHR for both groups and remained elevated for PLA until 48h post-DHR while fully recovering 24 h post-DHR for AJ. SOR was greater (p < 0.05) for PLA throughout the study. CK increased for both groups and was greater (p < 0.05) for PLA at 96 h post-DHR. IPT decreased for both groups but recovered faster for AJ (72 h) compared to PLA (no full recovery). AJ accelerated recovery of RE and EIMD and should be used in specific contexts, but not chronically.

This study aimed to investigate the effects of eccentric cycling (ECC_CYC) training on performance, physiological, and morphological parameters in comparison to concentric cycling (CON_CYC) training. Searches were conducted using PubMed, Embase, and ScienceDirect. Studies comparing the effect of ECC_CYC and CON_CYC training regimens on performance, physiological, and/or morphological parameters were included. Bayesian multilevel meta-analysis models were used to estimate the population’s mean difference between chronic responses from ECC_CYC and CON_CYC training protocols. Group levels and meta-regression were used to evaluate the specific effects of subjects and study characteristics. Fourteen studies were included in this review. The meta-analyses showed that ECC_CYC training was more effective in increasing knee extensor strength, vastus lateralis fiber cross-sectional area, and six-minute walking distance compared to CON_CYC. Moreover, ECC_CYC was as effective as CON_CYC in decreasing body fat percentage. CON_CYC was more effective in increasing $\dot{V}{O}_{2\max }$ and peak power output attained during concentric incremental tests. However, group-level analyses revealed that ECC_CYC was more effective than CON_CYC in improving $\dot{V}{O}_{2\max }$ in patients with cardiopulmonary diseases. ECC_CYC is a viable modality for exercise interventions aiming to improve parameters of muscle strength, hypertrophy, functional capacity, aerobic power, and body composition, with more advantages than CON_CYC training in improving neuromuscular variables.

Purpose: Explosive performance is increased right after performing loaded resistance exercise, which is known as post-activation performance enhancement (PAPE). Method: We investigated the effects of a plyometric exercise (PLYO) consisting of five sets of six drop-jumps from a 52-cm platform with a load corresponding to 20% body mass on changes in countermovement jump (CMJ) height in sedentary young men. Eleven young nonresistance trained men (19.6 ± 1.8 y, 69 ± 9 kg, 1.76 ± 0.08 m) who showed more than 4% increase in CMJ height at 4 min after five back squats with five-repetition maximum load participated in the study. Their responses to the back squat exercise were examined before (baseline) and 15 minutes, 24 and 48 hours post-PLYO. Exercise-induced muscle damage markers (maximal voluntary contraction torque [MVC], and quadriceps muscle soreness) were assessed at baseline, 15 minutes, 24 and 48 hours following PLYO. Results: MVC torque decreased (p < .05) at 15 minutes post-PLYO (−15.1 ± 9.7%) but returned to the baseline at 24 hours post-PLYO. Muscle soreness developed (p < .05) at 48 hours (21.0 ± 20.3 mm) after PLYO, indicating minor muscle damage. CMJ height increased (p < .05) after the five squats at baseline (7.6 ± 3.8%) indicating PAPE, but no such increase was found at 15 minutes, 24 and 48 hours after PLYO. However, CMJ height before the squat exercise was greater (p < .05) at 24 (5.9 ± 7.0%) and 48 hours post-PLYO (9.1 ± 8.5%) than the baseline. Conclusions: These results showed that PAPE disappeared after PLYO that induced minor muscle damage, but CMJ height increased at 24–48 hours in the recovery from PLYO exhibiting a priming effect.

We investigated if the same isometric preconditioning protocol (IPP) attenuates the magnitude of muscle damage induced by different maximal eccentric exercise protocols in the elbow flexors. Sixty-four untrained men were assigned to either two experimental or two control groups. Participants in the experimental groups performed an IPP prior to either slow (60°·s-1 – ISO+ECC-S) or fast (180°·s-1 – ISO+ECC-F) maximal eccentric contractions (MaxECC). Subjects in the control groups performed slow (ECC-S) or fast (ECC-F) MaxECC without IPP. Maximal isokinetic concentric torque (MVC), muscle soreness (SOR) and muscle thickness (MT) were assessed before, immediately after, and 1-4 days following the MaxECC. Significant (p < 0.05) group vs time interactions were found for MVC (F = 4,517), SOR (F = 6,318), and MT (F = 1,863). The ECC-S group presented faster (p<0.05) recovery of MVC and MT and less (p<0.05) SOR at 96h post-MaxECC compared with ECC-F group. No significant differences in MVC and MT were found between ECC-S and ECC-F groups following MaxECC. The ISO+ECC-S group showed faster (p<0.05) recovery of MVC and SOR compared to the ECC-S group. No significant differences were evident between ISO+ECC-S and ECC-S in any variable. The ISO+ECC-F group showed faster (p<0.05) recovery of all assessed variables compared with the ECC-F group. MVC was greater (p<0.05) at 48-72h and SOR was less (p<0.05) at 48-96h in the ISO+ECC-F compared to the ECC-F group. No significant differences were evident between ISO+ECC-S and ISO+ECC-F for any variable. These results show that the IPP accelerated recovery of MVC and SOR for the slow-eccentric exercise condition and attenuated strength loss and SOR in addition to faster recovery of all assessed variables for the fast-eccentric exercise condition. Therefore, the IPP can be used as a strategy to attenuate and accelerate recovery of muscle damage induced by different-velocity eccentric exercises, resulting in greater protection against muscle damage induced by faster velocity.

Article: Acute physiological responses to eccentric cycling: a systematic review and meta-analysis - The Journal of Sports Medicine and Physical Fitness 2023 Jul 06 - Minerva Medica - Journals