Delayed neuromuscular fatigue recovery unveils reduced fatigue tolerance in elderly following maximal intermittent exercise.

The aim of the study was to assess the impact of aging on neuromuscular fatigue and recovery. Ten young (23.08 ± 1.43 years) and older (61.19 ± 1.80 years) males performed an intermittent maximal isometric exercise with the knee extensors followed by 27 min of recovery. Maximal voluntary contraction (MVC), total work (W'), voluntary activation (VA), potentiated resting twitch (Ptw), and electromyography (EMG) were recorded and then analyzed. Peripheral and central fatigue following exercise were lower in old compared to young (- 29.99% vs. - 42.68% and - 14.55 vs. - 20.02%; P < 0.05, respectively). Despite old performing 50% less work, RMS/Mmax reduction was similar between old and young (- 26.46% vs. - 29.93%; P > 0.05, respectively). During the recovery period, our results showed that recovery of the MVC was impaired for old (14.93% for old vs. 30.66% for young) and still incomplete until 27 min.VA increased significantly compared to post exercise after 1 min only for young (P = 0.001), potentially affecting the recovery pattern of MVC during the early phase due to their significant correlation (r2 = 0.58, P = 0.01). Peripheral fatigue recovery was also lower for old (11.18% vs. 18.72%; P < 0.001), and both groups failed to recover their baseline value (both P < 0.005). The lower peripheral and central fatigue observed in elderly following exercise appears for the first instance as a fatigue resistance. However, the delayed neuromuscular recovery reveals instead a reduced fatigue tolerance reflecting age-related alteration within contractile properties and/or within central nervous system.

Cold Water Immersion Improves the Recovery of Both Central and Peripheral Fatigue Following Simulated Soccer Match-Play.

The present study aimed to investigate the effect of cold water immersion (CWI) on the recovery of neuromuscular fatigue following simulated soccer match-play. In a randomized design, twelve soccer players completed a 90-min simulated soccer match followed by either CWI or thermoneutral water immersion (TWI, sham condition). Before and after match (immediately after CWI/TWI through 72 h recovery), neuromuscular and performance assessments were performed. Maximal voluntary contraction (MVC) and twitch responses, delivered through electrical femoral nerve stimulation, were used to assess peripheral fatigue (quadriceps resting twitch force, Qtw,pot) and central fatigue (voluntary activation, VA). Performance was assessed via squat jump (SJ), countermovement jump (CMJ), and 20 m sprint tests. Biomarkers of muscle damages (creatine kinase, CK; Lactate dehydrogenase, LDH) were also collected. Smaller reductions in CWI than TWI were found in MVC (-9.9 ± 3%vs-23.7 ± 14.7%), VA (-3.7 ± 4.9%vs-15.4 ± 5.6%) and Qtw,pot (-15.7 ± 5.9% vs. -24.8 ± 9.5%) following post-match intervention (p < 0.05). On the other hand, smaller reductions in CWI than TWI were found only in Qtw,pot (-0.2 ± 7.7% vs. -8.8 ± 9.6%) at 72 h post-match. Afterwards, these parameters remained lower compared to baseline up to 48-72 h in TWI while they all recovered within 24 h in CWI. The 20 m sprint performance was less impaired in CWI than TWI (+11.1 ± 3.2% vs. +18 ± 3.6%, p < 0.05) while SJ and CMJ were not affected by the recovery strategy. Plasma LDH, yet no CK, were less increased during recovery in CWI compared to TWI. This study showed that CWI reduced both central and peripheral components of fatigue, which in turn led to earlier full recovery of the neuromuscular function and performance indices. Therefore, CWI might be an interesting recovery strategy for soccer players.

Chronic Beetroot Juice Supplementation Accelerates Recovery Kinetics following Simulated Match Play in Soccer Players.

OBJECTIVE: To assess the effect of beetroot juice (BET) on recovery kinetics of physical performance, muscle damage and perceived muscle soreness after simulated soccer match play in soccer players. METHOD: In a randomized, double-blind, crossover design, thirteen soccer players completed the Loughborough Intermittent Shuttle Test LIST. Players received either BET or placebo (PLA) (2*150) for 7 days (3 days pre-exercise, on the day trial, and 3 days post-exercise). Physical performance (Squat jump: SJ, countermovement jump: CMJ, maximal voluntary contraction: MVC, and 20 meters sprint: SP), blood markers of muscle damage (creatine kinase: CK, Lactate dehydrogenase: LDH), inflammatory parameter (C-reactive protein: CRP) and perceived muscle soreness (DOMS) were assessed at baseline, 0 h, 24 h, 48 h and 72 h following the exercise. RESULTS: Following the LIST, a decrease was observed in CMJ, MVC and SP at 0 h, 24 h, 48 h in both conditions (p < 0.05). However, compared to PLA session, this decrease was significantly attenuated with BET for CMJ at 24 h and at 48 h and for MVC at 0 h, 24 h, 48 h and for SP at 48 h after the LIST (p < 0.05). Likewise, DOMS values were significantly lower with BET compared to PLA condition immediately and at 24 h after exercise.CK, LDH and CRP levels increased at 0 h and at 24 h post exercise in both conditions (p < 0.05), but without any significant difference between the two condition (p > 0.05). CONCLUSION: The results of the present study suggest that chronic beetroot juice supplementation reduces post exercise perceived muscle soreness and maintain better performance during the recovery period in soccer players.

Brief cycles of lower-limb occlusion accelerate recovery kinetics in soccer players.

Objective: The aim of this study was to assess the effect of intermittent vascular occlusion (IVO) on recovery following simulated soccer physical demand test in soccer players.Methods: Twelve soccer players completed the Loughborough Intermittent Shuttle Test (LIST) in two conditions placebo (PLA) and IVO followed by intermittent lower-limb occlusion. Physical performance (Squat jump: SJ, countermovement jump: CMJ, maximal voluntary contraction: MVC, and 20 m sprint: SP), muscle damage parameters (creatine kinase: CK, Lactate dehydrogenase: LDH), inflammatory parameter (C-reactive protein: CRP), and perceived muscle soreness (DOMS) were assessed before, immediately after (0 h), and 24 h, 48 h, and 72 h following the exercise.Results: Following the LIST, a decrease was observed in all Physical performance within 48 h in PLA condition (p < 0.05), compared to PLA treatment, IVO treatment attenuated the decrease of SJ and CMJ at 24 h and at 48 h and for MVC and SP within 48 h after the LIST (p < 0.05). CK and LDH levels increased within 24 h post-exercise in both conditions (p < 0.05), but with a lower level in IVO compared to PLA condition (p < 0.05). Likewise, DOMS values were significantly lower with IVO condition compared to PLA condition immediately and at 24 h after exercise.Conclusion: The results of the present study suggest that the application of IVO after simulated soccer physical demand test accelerated recovery kinetics in soccer players.

Effects of Ramadan Fasting on Recovery Following a Simulated Soccer Match in Professional Soccer Players: A Pilot Study.

Objectives: Assessing the effects of Ramadan fasting on recovery following a soccer match simulation. Methods: Eight elite soccer players (age: 21.0 ± 0.4 years) performed a modified Loughborough Intermittent Shuttle Test protocol (LISTmod) on two occasions: 1 week before (BR) and during the fourth week of Ramadan (End-R). At BR and End-R, soccer players performed squat jump, countermovement jump, maximal voluntary contraction, and 20 m sprint, and creatine kinase, uric acid, and subjective ratings (feelings scale, quality of sleep, fatigue, muscle soreness and stress) were assessed at baseline and 0, 24, 48, and 72 h following LISTmod. Results: Following LISTmod, performance in squat jump (48 and 72 h) (p < 0.05), countermovement jump (48 and 72 h), maximal voluntary contraction (0, 24, 48, and 72 h), and 20 m sprint (0 and 48 h) decreased significantly on both occasions. Decreases were higher at End-R than BR. Creatine kinase levels increased significantly at 24 and 48 h at BR and End-R (p < 0.05). Uric acid increased at 0 and 24 h only on BR. Muscle soreness increased throughout the recovery period at both occasions, with a higher level at End-R. Stress rating increased only at 0 h on End-R, while fatigue rating increased at 24 h at BR and at 0, 24, and 48 h at End-R. Conclusion: Perturbations in physical performance and subjective ratings parameters were higher at the end of Ramadan. However, the results of this study showed that Ramadan fasting did not adversely affect the recovery following soccer match simulation in professional soccer players.

Faster physical performance recovery with cold water immersion is not related to lower muscle damage level in professional soccer players.

The aim of the present study was to assess the effects of cold water immersion (CWI) after an intermittent test on the recovery kinetic of physical performance, muscle damage and perceived muscle soreness in professionals soccer players. In a randomized design, eight soccer players completed the Loughborough Intermittent Shuttle Test followed by 10 min of either CWI (10C°) or thermoneutral water immersion (TWI) (28C°). Physical performance (Squat jump: SJ, countermovement jump: CMJ, maximal voluntary contraction: MVC, and 20 m sprint: SP), muscle damage parameter (creatine kinase: CK) and perceived muscle soreness were assessed at baseline, 0 h, 24 h, 48 h and 72 h after the intermittent test. After the test, a decrease was observed in SJ and in CMJ at 0 h, 24 h, 48 h and 72 h with TWI (p < 0.05) and only at 0 h for SJ with CWI (p < 0.05). SP decreased at 24 h and 48 h after the test with TWI (p < 0.05) and only at 24 h with CWI (p < 0.05). MVC, CK activity and perceived muscle soreness increased in both condition after the test and returned to baseline levels 72 h after the test with TWI (p < 0.05) and at 48 h with CWI (p < 0.05). For the correlation between physical performance and muscle damage parameters in CWI session, the statistical analysis didn't reveal any significant link between CK and SJ, CMJ, MVC or SP values (p > 0.05). The results suggest that CWI immediately after an intermittent test reduces muscle damage and perceived muscle soreness, and accelerate recovery of physical performance in professional soccer players. However, the faster recovery of physical performance seems not be related to the lower level of muscle damage induced by CWI.