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Purpose: The relationship between external load and creatine-kinase (CK) response at the team/position or individual level using Global Positioning Systems (GPS) has been studied. This study aimed to compare GPS-derived and Football Movement Profile (FMP) –derived CK-prediction models for national-team soccer players. The second aim was to compare the performance of general and individualized CK prediction models. Methods: Four hundred forty-four national-team soccer players (under 15 [U15] to senior) were monitored during training sessions and matches using GPS. CK was measured every morning from whole blood. The players had 19.3 (18.1) individual GPS-CK pairs, resulting in a total of 8570 data points. Machine learning models were built using (1) GPS-derived or (2) FMP-based parameters or (3) the combination of the 2 to predict the following days' CK value. The performance of general and individual-specific prediction models was compared. The performance of the models was described by R2 and the root-mean-square error (RMSE, in units per liter for CK values). Results: The FMP model (R2 =.60, RMSE = 144.6 U/L) performed similarly to the GPS-based model (R2 =.62, RMSE = 141.2 U/L) and the combination of the 2 (R2 =.62, RMSE = 140.3 U/L). The prediction power of the general model was better on average (R2 =.57 vs R2 =.37) and for 73% of the players than the individualized model. Conclusions: The results suggest that FMP-based CK-prediction models perform similarly to those based on GPS-derived metrics. General machine learning models' prediction power was higher than those of the individual-specific models. These findings can be used to monitor postmatch recovery strategies and to optimize weekly training periodization. [ABSTRACT FROM AUTHOR]

No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0.6 m. Exercise was repeated after 14 days. Using a 3-way (set × bout × group) design, changes in GRF were assessed with analysis of variance and statistical parametric mapping. Jump height, reactive strength, peak, and mean propulsive forces declined between sets (P <.001). Vertical stiffness, contact time, force at zero velocity, and propulsive duration increased (P <.05). According to statistical parametric mapping, braking (17%–25% of the movement) and propulsive forces (58%–81%) declined (P <.05). During the repeated bout, peak propulsive force and duration increased (P <.05), while mean propulsive force (P <.05) and GRF from 59% to 73% declined (P <.001). A repeated bout of DJs differed in propulsive GRF, without changes to the eccentric phase, or effects from CG. [ABSTRACT FROM AUTHOR]

Purpose: This brief report aimed to characterize inter-individual training responses following a single session of high-intense whole-body electromyostimulation (WB-EMS) using markers of muscle damage over a period of 72 h. Methods: Twelve healthy individuals (5 men, 7 women; 32.0 ± 7 years) participated in a single 20-minute high-intensity WB-EMS training session. Markers of muscle damage, creatine kinase (CK) and myoglobin (Mb), were assessed before and immediately after training, as well as at 1.5, 3, 24, 48 and 72 h post-exercise. Lactate levels were determined pre- and post-exercise. Results: Overall, WB-EMS induced significant CK elevations, peaking at 72 h (18.358 ± 21.380 U/L; p < 0.01), and correlating Mb levels peaking at 48 h (1.509 ± 1.394 ng/dl, p < 0.01). Despite significant inter-individual variability in CK levels, both slow (SR) and fast responders (FR) were identified. FR showed significant increases in CK at all time points post WB-EMS (p < 0.05), whereas CK in SR significantly elevated after 48 h. Post-WB-EMS lactate concentration was identified to predict peak CK and Mb levels (r ≥ 0.65, both p < 0.05). Conclusion: High-intensity WB-EMS has the potential to induce severe muscle damage, as indicated by elevated levels of CK and Mb. We identified two distinct groups of individuals, SR and FR, indicating variability in response to WB-EMS. Furthermore, we suggest that individual responses to WB-EMS can be predicted based on post-WB-EMS lactate concentration. [ABSTRACT FROM AUTHOR]

Unaccustomed eccentric exercise (EE) is protective against muscle damage following a subsequent bout of similar exercise. One hypothesis suggests the existence of an alteration in motor unit (MU) behaviour during the second bout, which might contribute to the adaptive response. Accordingly, the present study investigated MU changes during repeated bouts of EE. During two bouts of exercise where maximal lengthening dorsiflexion (10 repetitions × 10 sets) was performed 3 weeks apart, maximal voluntary isometric torque (MVIC) and MU behaviour (quantified using high‐density electromyography; HDsEMG) were measured at baseline, during (after set 5), and post‐EE. The HDsEMG signals were decomposed into individual MU discharge timings, and a subset were tracked across each time point. MVIC was reduced similarly in both bouts post‐EE (Δ27 vs. 23%, P = 0.144), with a comparable amount of total work performed (∼1,300 J; P = 0.905). In total, 1,754 MUs were identified and the decline in MVIC was accompanied by a stepwise increase in discharge rate (∼13%; P < 0.001). A decrease in relative recruitment was found immediately after EE in Bout 1 versus baseline (∼16%; P < 0.01), along with reductions in derecruitment thresholds immediately after EE in Bout 2. The coefficient of variation of inter‐spike intervals was lower in Bout 2 (∼15%; P < 0.001). Our data provide new information regarding a change in MU behaviour during the performance of a repeated bout of EE. Importantly, such changes in MU behaviour might contribute, at least in part, to the repeated bout phenomenon. What is the central question of this study?Is motor unit (MU) behaviour altered during the performance of an initial and repeated bout of eccentric exercise (EE)?What is the main finding and its importance?During the repeated bout of exercise, we observed a greater contribution from lower threshold MUs to force generation along with reduced firing rate variability. Results suggest an adaptation occurs during the performance of an initial bout of exercise and contributes to the accelerated recovery that occurs following the performance of a repeated bout of EE. Importantly, our data suggest that changes in MU behaviour contribute, partly, to the repeated bout phenomenon immediately upon performing a repeated bout of eccentric activity. [ABSTRACT FROM AUTHOR]

Introduction: Skeletal muscle satellite cells (SC) contribute to the adaptive process of resistance exercise training (RET) and may be influenced by nutritional supplementation. However, little research exists on the impact of multi-ingredient supplementation on the SC response to RET. Purpose: We tested the effect of a multi-ingredient supplement (MIS) including whey protein, creatine, leucine, calcium citrate, and vitamin D on SC content and activity as well as myonuclear accretion, SC and myonuclear domain compared with a collagen control (COL) throughout a 10-wk RET program. Methods: Twenty-six participants underwent a 10-wk linear RET program while consuming either the MIS or COL supplement twice daily. Muscle biopsies were taken from the vastus lateralis at baseline and 48 h after a bout of damaging exercise, before and after RET. Muscle tissue was analyzed for SC and myonuclear content, domain, acute SC activation, and fiber cross-sectional area (fCSA). Results: MIS resulted in a greater increase in type II fCSA following 10 wk of RET (effect size (ES) = 0.89) but not myonuclear accretion or SC content. Change in myonuclei per fiber was positively correlated with type I and II and total fiber hypertrophy in the COL group only, indicating a robust independent effect of MIS on fCSA. Myonuclear domain increased similarly in both groups, whereas SC domain remained unchanged following RET. SC activation was similar between groups for all fiber types in the untrained state but showed a trend toward greater increases with MIS after RET (ES = 0.70). Conclusions: SC responses to acute damaging exercise and long-term RET are predominantly similar in MIS and COL groups. However, MIS can induce greater increases in type II fCSA with RET and potentially SC activation following damage in the trained state. [ABSTRACT FROM AUTHOR]

This study aimed to compare the acute inflammatory response following high-intensity eccentric exercise between resistance-trained young and master athletes with similar performance levels. Resistance-trained young (n=8; 22±2 years) and master (n=8; 52±4 years) male athletes of a similar performance level performed a standardized high-intensity eccentric squat exercise protocol (10 sets of half-squats at 70% of 1-repetition maximum). The serum concentration of 20 biomarkers related to tissue damage, inflammation, remodeling, and repair was measured at baseline, immediately after exercise, and over a 72 h recovery period. Both groups experienced similar muscle damage as evidenced by a comparable increase in creatine kinase activity 24 h after exercise (p<0.001). Interleukin-6 (p=0.009) and growth hormone (p<0.001) increased immediately post-exercise in both groups. Monocyte chemoattractant protein-1 increased immediately post-exercise only in young athletes (p=0.003) and then decreased 24 h later. There were no significant differences for the remaining variables, including cell markers related to neutrophil/macrophage activation or pro/anti-inflammatory cytokines. Resistance-trained young and master athletes, matched for performance level, showed an overall similar inflammatory response to eccentric exercise, possibly reflecting regulatory mechanisms or immunological adaptations to chronic stimulation in master athletes. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of 2 plyometric training (PT) sessions on postural control (PC). Twelve physically active men (27.5 ± 6.41 years, 82.7 ± 13.0 kg, and 24.17 ± 8.87%F) performed PT in two moments (week 1 and week 3), with a 14-day recovery period. The PT consisted in 10 series of 10 CMJ jumps, with 1 min rest intervals. PC parameters were measured during 30 s, double-leg stance stabilometry trials with eyes open and closed on a force platform. Additionally, knee extensors and flexors maximal voluntary isometric contraction (MVIC) were evaluated at 90° and 70° knee joint positions using an isokinetic dynamometer (Biodex System 4 Pro, Biodex Medical Systems, United States) with participants seated at 85° hip flexion (0° = full hip extension). In both weeks, PC and MVIC were assessed before (Pre), and after 24, 48 and 72 h of the PT session. Significant changes were observed 24 h after the jump protocol for MVIC of the knee extensors (F = 3,66, P = 0.005). No changes during the recovery time were found for the MVIC of knee flexors. No week * time interactions were observed for any of the evaluated PC parameters (eyes open and closed). The PT used was able to reduce the MVIC of the knee extensors after 24 h,but failed to cause changes in PC parameters. [ABSTRACT FROM AUTHOR]

Crush syndrome, which frequently occurs in earthquake disasters, often leads to rhabdomyolysis induced acute kidney injury (RIAKI). Recent findings indicate that systemic inflammatory response syndrome (SIRS) exacerbates muscle collapse, contributing to RIAKI. The purpose of this study is to investigate the involvement of multiple site inflammation, including intraperitoneal, in crush syndrome. In a mouse model of RIAKI, elevated levels of inflammatory mediators such as TNFα, IL-6, myoglobin, and dsDNA were observed in serum and the peritoneal cavity, peaking earlier in the intraperitoneal cavity than in serum or urine. Our previously developed novel peptide inhibiting leukocyte extracellular traps was administered intraperitoneally and blocked all of these mediators in the intraperitoneal cavity and serum, ameliorating muscle damage and consequent RIAKI. Although further studies are needed to determine whether intraperitoneal inflammation associated with muscle collapse can lead to systemic inflammation, resulting in more severe and prolonged muscle damage and renal injury, early suppression of multiple site inflammation, including intraperitoneal, might be an effective therapeutic target. [ABSTRACT FROM AUTHOR]

Exertional rhabdomyolysis (ER) is a condition where muscle breakdown occurs after intense and unaccustomed exercise in healthy individuals. It is characterized by muscle pain, weakness, and myoglobinuria, potentially leading to acute kidney injury and worsening the patients' prognosis. Ultra-trail races (UT) necessitate high energy and extreme muscular exertion, which can result in significant muscle breakdown, leading to ER and elevated biomarkers such as creatine kinase (CK) and lactate dehydrogenase (LDH). These races involve longer durations and both uphill and downhill elevations, with the latter causing more muscle damage. This systematic review aims to analyse the effect of downhill elevation (at least 1000 m) in UT on muscle and liver damage biomarkers. We conducted a systematic review of four electronic databases (Pubmed, Web of Science, Scopus, and Sportdiscus) based on PRISMA guidelines for systematic reviews. We included a total of 15 articles out of 6670 published between January 2005 and March 2024. The total population sample included 348 subjects, comprising 294 men (84.48%) and 54 women (15.52%) with a mean age of 39.82 ± 6.89 years. Only one subject (0.28%) was diagnosed with ER. The median increase in CK post vs. pre was 5370.63 ± 7289.71%, LDH post vs. pre was 311.20 ± 164.4%, and liver damage biomarkers aspartate transaminase (AST) and alanine aminotransferase (ALT) obtained mean increases of 1009.94 ± 743.97% and 207.02 ± 92.84%, respectively. No liver injury cases were reported. These findings suggest that ER is often misdiagnosed in UT and may result in acute kidney injury under certain circumstances. Therefore, it is crucial to define and prepare the characteristics required for ultra runners to safely participate in these extreme races. [ABSTRACT FROM AUTHOR]

Introduction: The effect of eccentric exercise--induced muscle damage (EIMD) on cycling efficiency is unknown. The aim of the present study was to assess the effect of EIMD on gross and delta efficiency and the cardiopulmonary responses to cycle ergometry. Methods: Twenty-one recreational athletes performed cycling at 70%, 90%, and 110% of the gas exchange threshold (GET) under control conditions (Control) and 24 h following an eccentric damaging protocol (Damage). Knee extensor isometric maximal voluntary contraction, potentiated twitch (Qtw,pot), and voluntary activation were assessed before Control and Damage. Gross and delta efficiency were assessed using indirect calorimetry, and cardiopulmonary responses were measured at each power output. Electromyography root-mean-square (EMGRMS) during cycling was also determined. Results: Maximal voluntary contraction was 25%± 18%lower for Damage than Control (P < 0.001). Gross efficiency was lower for Damage than Control (P < 0.001) by 0.55% ± 0.79%, 0.59% ± 0.73%, and 0.60% ± 0.87% for 70%, 90%, and 110% GET, respectively. Delta efficiency was unchanged between conditions (P = 0.513). Concurrently, cycling EMGRMS was higher for Damage than Control (P = 0.004). An intensity-dependent increase in breath frequency and ... was found, which were higher for Damage only at 110% GET (P ≤ 0.019). Conclusions: Thus, gross efficiency is reduced following EIMD. The concurrently higher EMGRMS suggests that increases in muscle activation in the presence of EIMD might have contributed to reduced gross efficiency. The lack of change in delta efficiency might relate to its poor reliability hindering the ability to detect change. The findings also show that EIMD-associated hyperventilation is dependent on exercise intensity, which might relate to increases in central command with EIMD. [ABSTRACT FROM AUTHOR]

Copyright of Kirkuk Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Unaccustomed eccentric exercise (EE) is protective against muscle damage following a subsequent bout of similar exercise. One hypothesis suggests the existence of an alteration in motor unit (MU) behaviour during the second bout, which might contribute to the adaptive response. Accordingly, the present study investigated MU changes during repeated bouts of EE. During two bouts of exercise where maximal lengthening dorsiflexion (10 repetitions × 10 sets) was performed 3 weeks apart, maximal voluntary isometric torque (MVIC) and MU behaviour (quantified using high‐density electromyography; HDsEMG) were measured at baseline, during (after set 5), and post‐EE. The HDsEMG signals were decomposed into individual MU discharge timings, and a subset were tracked across each time point. MVIC was reduced similarly in both bouts post‐EE (Δ27 vs. 23%, P = 0.144), with a comparable amount of total work performed (∼1,300 J; P = 0.905). In total, 1,754 MUs were identified and the decline in MVIC was accompanied by a stepwise increase in discharge rate (∼13%; P

The Brazilian army recently developed the military physical training “Cross Operational” (CO), composed of four different difficulty levels. The moderate/high intensity character of CO can damage the muscle fibers, characterized by alterations at the cellular level, which can be evaluated indirectly by intramuscular proteins showing up in the bloodstream. In this context, the analysis of muscle damage biomarkers can be used as part of an initial injury prevention tool and in the evaluation of training progression and post-exercise recovery. This study aimed to observe the acute effect of CO on indirect markers of muscle damage in military personnel of the Brazilian army. Twenty-four male recruits aged between 18 and 26 years participated in the study. The four sessions corresponding to the CO levels were performed in cross-design, with a seven-day washout period, and blood samples were collected at rest, immediately after, 24 and 48 hours after each training session. The measured markers were creatine kinase (CK), myoglobin (Mb) and lactate dehydrogenase (LDH). In all CO levels, CK had a significant increase 24 hours after CO, whereas Mb and LDH incresead immediately after CO. Regarding recovery time, LDH returned to baseline values within 48 hours in all levels, whereas CK and Mb, after 48 hours of recovery, reduced but did not return to baseline in level 4. The serum elevations of the biomarkers studied, like those found in studies with other consolidated physical training methods, suggest that CO can contribute to the improvement of the physical training of military personnel.

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Maca extract may regulate oxidative stress and muscle damage after exhaustive endurance exercise (EEE); however, its impact on these physiological activities remains obscure. OBJECTIVE: To examine the effects of Maca extract supplementation on oxidative stress, muscle damage and aerobic capacity after EEE. METHODS: Twenty healthy men were assigned to Maca or placebo groups and received two doses per day for 12 weeks. Pre- and post-EEE tests assessed levels of oxidative stress and muscle damage. The EEE test also recorded metrics such as time to exhaustion, peak oxygen consumption, and maximal and average heart rates. RESULTS: Post-exercise, there was no significant difference in oxidative stress markers between the Maca and placebo groups. However, the Maca group exhibited lower stress levels at both Post-4 and Post-24 in comparison to Post-0, while the placebo group only displayed a decrease at Post-4. Notably, Maca extract supplementation immediately increased catalase activity at Post-0. Though muscle damage markers did not significantly differ, the slope of CK elevation in the Maca group appeared lower than the Placebo group, suggesting Maca's potential in preventing muscle damage. However, no differences were noted on aerobic capacity markers. CONCLUSIONS: Maca extract may have some beneficial effects on reducing oxidative stress and possibly muscle damage after EEE. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of acute curcumin (CURC) supplementation on recovery from a soccer match in male professional players. Methods: In a randomized, placebo-controlled, crossover design, 11 players from the under-23 team of an English Premier League club (age 19 [1] y, body mass 79.4 [7.9] kg, height 180.8 [5.7] cm) consumed 500 mg of CURC or a control (medium-chain triglycerides) immediately and 12 and 36 hours after a 90-minute match. Countermovement jump height (CMJ), reactive strength index (RSI), delayed-onset muscle soreness (DOMS, 0–200 mm), and subjective well-being were measured before and 12, 36, and 60 hours postmatch. Global positioning systems measured external load during matches, and dietary intake was recorded across the testing period. Results: External load and dietary intake did not differ between conditions (P ≥.246). CURC attenuated deficits in CMJ (P ≤.004) and RSI (P ≤.001) and reduced DOMS (P ≤.004) at all postmatch time points (except 60 h post for RSI). The greatest difference between control and CURC was 12 hours post for CMJ (P <.001, 1.91 [4.40] cm, 95% CI, 1.25 to 2.57, g = 0.36) and RSI (P =.003, 0.40 [0.41] AU, 95% CI, 0.17 to 0.63, g = 0.90) and 36 hours post for DOMS (P <.001, 47 [23] mm, 95% CI, −67 to −27, g = 2.12). Conclusions: CURC intake <36 hours after a soccer match attenuated DOMS and muscle function deficits, suggesting that CURC may aid recovery in professional male soccer players. [ABSTRACT FROM AUTHOR]

Exertional rhabdomyolysis (ER) is a condition where muscle breakdown occurs after intense and unaccustomed exercise in healthy individuals. It is characterized by muscle pain, weakness, and myoglobinuria, potentially leading to acute kidney injury and worsening the patients’ prognosis. Ultra-trail races (UT) necessitate high energy and extreme muscular exertion, which can result in significant muscle breakdown, leading to ER and elevated biomarkers such as creatine kinase (CK) and lactate dehydrogenase (LDH). These races involve longer durations and both uphill and downhill elevations, with the latter causing more muscle damage. This systematic review aims to analyse the effect of downhill elevation (at least 1000 m) in UT on muscle and liver damage biomarkers. We conducted a systematic review of four electronic databases (Pubmed, Web of Science, Scopus, and Sportdiscus) based on PRISMA guidelines for systematic reviews. We included a total of 15 articles out of 6670 published between January 2005 and March 2024. The total population sample included 348 subjects, comprising 294 men (84.48%) and 54 women (15.52%) with a mean age of 39.82 ± 6.89 years. Only one subject (0.28%) was diagnosed with ER. The median increase in CK post vs. pre was 5370.63 ± 7289.71%, LDH post vs. pre was 311.20 ± 164.4%, and liver damage biomarkers aspartate transaminase (AST) and alanine aminotransferase (ALT) obtained mean increases of 1009.94 ± 743.97% and 207.02 ± 92.84%, respectively. No liver injury cases were reported. These findings suggest that ER is often misdiagnosed in UT and may result in acute kidney injury under certain circumstances. Therefore, it is crucial to define and prepare the characteristics required for ultra runners to safely participate in these extreme races.

Abstract A significant increase in circulating cell‐free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle‐damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low‐frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed‐onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low‐frequency fatigue and delayed‐onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P

Abstract Changes in protein turnover play an important role in dynamic physiological processes, including skeletal muscle regeneration, which occurs as an essential part of tissue repair after injury. The inability of muscle tissue to recapitulate this regenerative process can lead to the manifestation of clinical symptoms in various musculoskeletal diseases, including muscular dystrophies and pathological atrophy. Here, we employed a workflow that couples deuterated water (2H2O) administration with mass spectrometry (MS) to systematically measure in-vivo protein turnover rates across the muscle proteome in 8-week-old male C57BL6/J mice. We compared the turnover kinetics of over 100 proteins in response to cardiotoxin (CTX) induced muscle damage and regeneration at unique sequential stages along the regeneration timeline. This analysis is compared to gene expression data from mRNA-sequencing (mRNA-seq) from the same tissue. The data reveals quantitative protein flux signatures in response to necrotic damage, in addition to sequential differences in cell proliferation, energy metabolism, and contractile gene expression. Interestingly, the mRNA changes correlated poorly with changes in protein synthesis rates, consistent with post-transcriptional control mechanisms. In summary, the experiments described here reveal the signatures and timing of protein flux changes during skeletal muscle regeneration, as well as the inability of mRNA expression measurements to reveal changes in directly measured protein turnover rates. The results of this work described here provide a better understanding of the muscle regeneration process and could help to identify potential biomarkers or therapeutic targets.

Eccentric training induces greater hypertrophy while causing more muscle damage than concentric training. This study examined the effects of small-range eccentric contractions (SR-ECCs) and large-range eccentric contractions (LR-ECCs) on muscle morphology, contractility, and damage in rats. Thirty male Fischer 344 rats were divided into five groups: small-range ECC single-bout (SR-ECCSB, n = 4), large-range ECC single-bout (LR-ECCSB, n = 4), SR-ECC intervention (SR-ECCIntv, n = 7), LR-ECC intervention (LR-ECCIntv, n = 8), and control (Cont, n = 7). These groups underwent transcutaneous electrical stimulation involving 80 ECCs twice a week for four weeks. The results indicated that the LR-ECCSB group had more Evans blue dye-positive fibers than other groups. The SR-ECCIntv group showed no increase in the mean myofiber cross-sectional area. However, Pax7+ and Ki67+ cells significantly increased in both ECCIntv groups compared to the Cont group, and the connective tissue area was significantly greater in the LR-ECCIntv than in others. Muscle force was lower in both ECCIntv groups compared to the Cont group. These findings suggest that SR-ECC intervention may induce a smaller increase in the number of fibers with a large myofiber cross-sectional area and satellite cell proliferation with less muscle damage and myofibrosis compared to LR-ECCs. [ABSTRACT FROM AUTHOR]

Tart cherry (TC) consumption has become a popular nutritional strategy for recovery, particularly for the attenuation of markers associated with muscle damage. However, there are relatively few studies that have examined an acute dosing strategy. The aim of this pilot study was to explore the feasibility of using powdered Vistula TC for recovery following a bout of muscle-damaging exercise. Twenty-two recreationally active participants (mean ± SD age, stature, and mass were 23 ± 3 years old, 173 ± 10 cm, and 74 ± 17 kg, respectively) performed 40 (5 sets of 8 repetitions) maximal lengthening contractions of the elbow flexors. The participants were randomised to receive either a spray-dried TC extract or a calorie-matched placebo (12 TC, 10 placebo) for 4 days in total, starting on the day of exercise. Dependent measures of maximal voluntary contraction (MVC), muscle soreness (assessed via visual analogue scales; VAS), pain pressure threshold (PPT), range of motion (ROM), and upper arm limb girth were taken at baseline (pre), 24, 48, and 72 h post damaging exercise. There were significant changes over time among all the variables (MVC, VAS, PPT, ROM, and girth, p ≤ 0.014). There were no significant differences between the conditions for any of the variables (MVC, VAS, PPT, ROM, and girth, p > 0.3). The TC group did not recover at an accelerated rate compared to the placebo. This study provides initial insights into the use of powdered Vistula TC and its effect following strenuous (damaging) exercise bouts. Vistula TC did not improve recovery when taken acutely following a bout of damaging exercise to the elbow flexors. [ABSTRACT FROM AUTHOR]

Fullerene C60 exhibits potent antioxidant anti-inflammatory activities as well as anticancer activities. In this study using 60 Wistar albino female rats (n = 60, 8 weeks old), they rats were divided into 4 groups, including 15 rats each. The groups were arranged as follows: (i) Control Group: Group fed with standard diet; (ii) C60 Group: C60 (1.7 mg/kg bw, oral gavage); (iii) DMBA (7,12-dimethylbenz[a]anthracene) Group: DMBA (45 mg/kg bw, oral gavage); (iv) C60 and DMBA Group: C60 (1.7 mg/kg bw, oral gavage) and DMBA (45 mg/kg bw, oral gavage) group. DMBA increased the malondialdehyde levels in muscle tissue, while decreasing GSH and CAT levels; however, treatment with fullerene C60 reversed these effects. In addition, the oral administration of fullerene C60 increased caspase-3 and Nrf-2 protein expression and significantly decreased Bcl-2, NF-κB, TNF-α, COX-2 and p38α (MAPK) protein expression in C60 + DMBA compared to the DMBA group. Moreover, histopathological imaging revealed that the oral administration of fullerene C60 decreases inflammatory cells, edema formation, and hydropic degeneration in the muscles. Taken together, the results of the present study indicated that fullerene C60 nanoparticle provides effective protection by preventing muscle tissue damage. [ABSTRACT FROM AUTHOR]

A significant increase in circulating cell‐free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle‐damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low‐frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed‐onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low‐frequency fatigue and delayed‐onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P < 0.01). Elevation of postexercise cfDNA was correlated with both more pronounced low‐frequency fatigue (r = −0.52, P = 3.4 × 10−11) and delayed‐onset muscle soreness (r = 0.32, P = 0.00019). Levels of cfDNA change in response to severe primary and secondary muscle damage after exercise. Levels of cfDNA exhibit a stronger correlation with variables related to primary muscle damage than to secondary muscle damage, suggesting that cfDNA is a more sensitive marker of acute loss of muscle function than of secondary inflammation or damaged muscle fibres. What is the central question of this study?How do plasma cell‐free DNA (cfDNA) levels change in response to primary and secondary muscle damage when muscle‐damaging exercise is performed without metabolic stress?What is the main finding and its importance?In this study, we found that cfDNA concentration increases following severe primary and secondary muscle damage after 50 drop jumps. However, acute postexercise increases in cfDNA were higher than following secondary muscle damage and were more correlated with variables related to primary muscle damage (low‐frequency fatigue). This suggests that muscle‐damaging exercise causing no accumulation of metabolites can lead to acute and delayed increases in cfDNA levels. However, they are more sensitive to primary muscle damage. [ABSTRACT FROM AUTHOR]

Icing interventions on the injured skeletal muscle affect the macrophage-related regenerative events and muscle repair. However, despite its importance for the practice in sport medicine, the influence of different icing protocols on muscle regeneration remains unclear. Here, using a rodent model of mild muscle injury with necrosis in a small fraction of myofibers, the injured animals were allocated to four groups: non-icing control (Con) and a single treatment (Ice-1), three treatments (Ice-3), or nine treatments (Ice-9) with a 30-min icing each time within two days following injury. Muscle regeneration was compared between the groups on post-injury days 1, 3, 5, and 7. The results showed that compared with the Con group, muscle regeneration was faster in the Ice-9 group (but not in the Ice-1 and Ice-3 groups), as indicated by more rapid accumulation of satellite cells within the regenerating area and enlarged size of regenerating myofibers (p <0.05, respectively). There was also less macrophage accumulation (p <0.05) and a trend toward early removal of necrotic myofibers in the damaged/regenerating area in the Ice-9 group (p =0.0535). These results demonstrate that in the case of mild muscle damage, more frequent icing treatment is more effective to stimulate muscle regeneration. [ABSTRACT FROM AUTHOR]

This study proposes to monitor the physical, immune and cognitive responses and adaptations of elite rugby players throughout the season based on the loads performed. Anthropometric measurements, physical fitness tests (e.g., muscle strength and power, linear and change-of-direction speed, cardiorespiratory fitness) and analyses of serum concentrations of markers of muscle damage (creatine kinase [CK] and lactate dehydrogenase [LDH]) and brain-derived neurotrophic factor (BDNF) were carried out over a sporting season (24 weeks) for 17 elite rugby players (10 forwards and 7 backs) aged 18.91 ± 0.76 years. The physical fitness test results show improvements in the performance of both forwards and backs over the season (p < 0.05), with an advantage for backs compared with forwards in most tests (p < 0.05). Muscle damage markers decreased at the end of the season compared with the baseline levels for forwards (p < 0.05). CK levels were unchanged for the backs, but there were increased LDH concentrations at the end of the season compared with baseline (p < 0.05). Serum BDNF levels decreased for the total group between the second and third sampling (p < 0.05). The muscular and physical capacities of rugby players differ according to their playing position. Immune responses and adaptations, as well as BDNF levels, vary throughout the season and depend on the physical load performed. [ABSTRACT FROM AUTHOR]

Introduction: Artistic gymnastics is one of the most demanding sports disciplines, with the athletes demonstrating extremely high levels of explosive power and strength. Currently, knowledge of the effect of gymnastic training adaptation on exercise-induced inflammatory response is limited. The study aimed to evaluate inflammatory response following lower- and upper-body high-intensity exercise in relation to the iron status in gymnasts and non-athletes. Methods: Fourteen elite male artistic gymnasts (EAG, 20.6 ± 3.3 years old) and 14 physically active men (PAM, 19.9 ± 1.0 years old) participated in the study. Venous blood samples were taken before and 5 min and 60 min after two variants of Wingate anaerobic test (WAnT), upper-body and lower-body WAnT. Basal iron metabolism (serum iron and ferritin) and acute responses of selected inflammatory response markers [interleukin (IL) 6, IL-10, and tumour necrosis factor a] were analysed. Results: EAG performed significantly better during upper-body WAnT than PAM regarding relative mean and peak power. The increase in IL-6 levels after upperbody WAnT was higher in EAG than in PAM; the opposite was observed after lower-body WAnT. IL-10 levels were higher in EAG than in PAM, and tumour necrosis factor a levels were higher in PAM than those in EAG only after lowerbody WAnT. The changes in IL-10 correlated with baseline serum iron and ferritin in PAM. Discussion: Overall, gymnastic training is associated with the attenuation of irondependent post-exercise anti-inflammatory cytokine secretion. [ABSTRACT FROM AUTHOR]

Exhaustive exercise is known to induce muscle damage characterized by inflammation and oxidative stress. Although "regular" and "weekend warrior" exercise regimens have been shown to confer comparable health benefits in human studies, such as reduced risks of all-cause, cardiovascular disease (CVD), and cancer mortality, their differential impacts on muscle damage post-exhaustive exercise remain unclear. This study aimed to compare the effects of long-term, moderate-intensity (LTMI) and short-term, high-intensity (STHI) training modalities, matched for total exercise volume, on gut microbiota, short-chain fatty acids (SCFAs), and exhaustive exercise-induced muscle damage in mice, as well as to evaluate the correlation between these factors. LTMI is considered a regular exercise regimen, while STHI shares some similarities with the "weekend warrior" pattern, such as promoting exercise intensity and condensing training sessions into a short period. Our findings indicate that LTMI training significantly enhanced the abundance of SCFA-producing bacteria, including Akkermansia, Prevotellaceae_NK3B31_group, Odoribacter, Alistipes, and Lactobacillus, thereby increasing SCFA levels and attenuating muscle damage following exhaustive swimming. In contrast, STHI training increased the abundance of opportunistic pathogens such as Staphylococcus and Bilophila, without altering SCFA levels, and was associated with exacerbated muscle damage. Moreover, we observed a significant negative correlation between the abundance of SCFA-producing bacteria and SCFA levels with the expression of inflammatory cytokines in the muscle of mice post-exhaustive exercise. Conversely, the abundance of Staphylococcus and Bilophila showed a notable positive correlation with these cytokines. Additionally, the effects of LTMI and STHI on exhaustive exercise-induced muscle damage were transmissible to untrained mice via fecal microbiota transplantation, suggesting that gut microbiota changes induced by these training modalities may contribute to their contrasting impacts on muscle damage. These results underscore the significance of selecting an appropriate training modality prior to engaging in exhaustive exercise, with implications for athletic training and injury prevention. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing interest in relation to the female athlete, especially in widespread disciplines such as football. Concerns about vitamin D deficiency status have recently been considered due to its effects on the performance and health status of female footballers. However, its relationship to body composition and muscle damage in female football athletes remains unclear to date. The purpose of the present study was to analyse the association of the vitamin D status of Spanish elite female football players with anthropometric variables and markers of muscle damage. Ethical consent was obtained from a total of 21 players from a Spanish elite women's football team (20–33 years). Anthropometric analysis was carried out according to the standardised protocol of the International Society for the Advancement of Kineanthropometry (ISAK). The clinical analyses, based on urine and blood samples, were carried out by the club's medical staff at the start of the season in the early morning in a fasting state. The athletes were also asked about the regularity of their menstrual cycle and some dietary habits. Thirty-three percent of the female athletes had vitamin D levels below the reference values. Significantly higher FM values were observed in athletes with low vitamin D status (p < 0.05), as well as statistically significant negative correlations between vitamin D levels and FM (p < 0.05) in the group of female players with vitamin D levels below the baseline values. No significant associations were observed between markers of muscle damage and the other variables. Complementing an assessment of body composition with a biochemical analysis of vitamin D levels may be an interesting strategy in the process of monitoring the elite female football player throughout the season. [ABSTRACT FROM AUTHOR]

Purpose: This study examined how a low dose of an eccentric-oriented lunge exercise could induce the repeated-bout effect (RBE) and affect the subsequent post-activation performance enhancement (PAPE) in recreational runners. Methods: Twenty male recreational runners (32.1 ± 2.8 years; 173.4 ± 6.1 cm; 73.3 ± 11.5 kg; 57.8 ± 7.2 mL·kg−1·min−1) were divided into control (N = 10) and experimental (N = 10) groups. In the first and fourth weeks, the groups were assessed for jump capacity, dynamic balance, and submaximal running kinematics before and after an incremental shuttle-run test until exhaustion. The experimental group was also submitted to two sessions of the eccentric-oriented lunge exercise (3 sets of 10 repetitions with 2 min of passive recovery) in the second and third weeks. Results: We observed that the first session promoted muscle damage, which was significantly (p < .05) reduced after the second training session, thus indicating an RBE. Meanwhile, there was no effect of the RBE on dynamic balance and submaximal running kinematics in the post-intervention. However, there was a significant increase in countermovement jump height (p = .008) for the experimental group when compared to the control group, although no PAPE was observed. Conclusions: The current results demonstrate that a simple, low-dose eccentric-oriented exercise may induce an RBE, leading to reduced muscle damage and a possibly improved lower limbs’ muscle power in recreational runners. However, the absence of PAPE effects suggests that the RBE may not directly influence the potentiation/fatigue balance after fatiguing running exercises. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effects of acai supplementation (AS) on markers of muscle damage. Twelve men participated in the 21-day study. All performed the damage protocol (DP) in two moments, separated by 7 days. The DP consisted of 10 sets of 10 CMJs, with a recovery of 1 min between sets. The AS was performed for 7 days with 40 g/day of dehydrated acai (GA) or placebo (GP). Blood parameters (CK, LDH and Trolox-equivalent antioxidant capacity – TEAC) were evaluated at 0 h and 24 h. Ultrasound images (VL, RF and GM), DOMS in lower limbs and isometric peak torque (IPT) of knee extensors and flexors were evaluated at 0 h, 24 h, 48 h and 72 h after DP. A time–treatment interaction was observed for TEAC (p = 0.01), in which the GA presented increases of 11% after 24 h. Similarly, time–treatment interaction was observed for knee flexors IPT (p = 0.02), where GA showed superior recovery after 24 h (GA = 108 ± 23 vs. GP = 92 ± 24 N∙m) and 72 h (GA = 113 ± 31 vs. GP = 98 ± 26 N∙m). No significance was observed in the fatigue index for knee extensors (p = 0.75) and flexors (p = 0.89), indicating similar fatigue in both situations. We concluded that AS increased the TEAC and promoted faster recovery of the knee flexors IPT when compared to GP. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the effect of pre-exercise whole-body cryotherapy (WBC) on muscle damage indicators following eccentric treadmill exercise in young women. Methods: Twenty-seven participants underwent two 1-h downhill treadmill runs, replicating 60% of their maximal oxygen uptake, with a 4-week intermission for recovery and treatment application. In this intermission, one group underwent 20 sessions of WBC, delivered five times a week at -120°C for 3 min each, while the comparison group received no such treatment. Markers of muscle injury--serum myoglobin concentration, creatine kinase and lactate dehydrogenase activity and also uric acid, and cell-free DNA concentration--were measured before and after downhill runs. Results: The study observed a notable reduction in post-exercise myoglobin and CK levels in the WBC group after the second running session. Discussion: The results suggest that WBC can have a protective effects against muscle damage resulting from eccentric exercise. [ABSTRACT FROM AUTHOR]

Omega-3 is a family of n-3 polyunsaturated fatty acids (PUFAs), which have been used to treat a wide variety of chronic diseases, due mainly to their antioxidant and anti-inflammatory properties, among others. In this context, omega-3 could be post-exercise recovery agent and sports supplement that could improve performance by preserving and promoting skeletal muscle mass and strength. No conclusive evidence, however, exists about the potential effects of omega-3 on post-exercise biomarkers and sports performance in physically healthy adults. Based on the PRISMA in Exercise, Rehabilitation, Sports Medicine, and Sports Science (PERSiST) guidelines, we systematically reviewed studies indexed in Web of Science, Scopus, and Medline to assess the effects of omega-3 on post-exercise inflammation, muscle damage, oxidant response, and sports performance in physically healthy adults. The search was performed on original articles published in the last 10 years up to 5 May 2024, with a controlled trial design in which omega-3 supplementation was compared with a control group. Among 14,971 records identified in the search, 13 studies met the selection criteria. The duration of the interventions ranged from 1 day to 26 weeks of supplementation and the doses used were heterogeneous. Creatine kinase (CK) and lactate dehydrogenase (LDH) were significantly higher (p < 0.05) in the control group in 3 of the 4 studies where these markers were analyzed. C-reactive protein (CRP) was significantly higher (p < 0.05) in the control group of 2 of the 13 studies where this marker was analyzed. The delayed onset muscle soreness (DOMS) gave mixed results. Interleukin 6 (IL-6) showed improvements with supplementation, but tumor necrosis factor-α (TNF-α) displayed no differences. The consumption of n-3 PUFAs improved some indicators of oxidative stress such as reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. Additional evidence is needed to establish clear recommendations regarding the dose and length of n-3 PUFA supplements. These may benefit the post-exercise inflammatory response, mitigate muscle damage, and decrease oxidative stress caused by exercise. However, studies did not evaluate omega-3 status at baseline or following supplementation and therefore the observations must be treated with caution. [ABSTRACT FROM AUTHOR]

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Delayed Onset Muscle Soreness (DOMS) is the muscle pain and stiffness following unaccustomed or strenuous physical activity that initially appears 8 - 20 h after exercise, peaks at 24 - 48 h after exercise and persists for several days and affect performance. The aim of the present study was to examine the physiological effects of selenium supplementation on delayed-onset muscle soreness and muscle damage. Thirty-two recreational male students of Sports Science Department, Universitas Negeri Surabaya were randomly and double-blindly assigned to either a selenium supplementation group (n=16) or a Placebo group (n=16) and were directed to take either a selenium capsule or a placebo for a period of 3-weeks. Following the 3-weeks supplementation period, both groups underwent a 10-set x 10-rep countermovement jump (1-min recovery between sets) as an eccentric exercise protocol. Pain of DOMS and CK level were measured prior to the eccentric exercise 1-hr before, 24-hr and 48-hr after eccentric exercise. the result of this study showed that both groups experienced Delayed Onset Muscle Soreness (DOMS) and increased total CK serum within 24 to 48 hours post heavy eccentric exercise. The results indicated that the selenium-supplemented group had a significantly greater reduction in plasma DOMS and total CK serum compared to the Placebo group (p<0.05). In summary, selenium supplementation might lower the risk of muscle injury after heavy eccentric exercise, as it effectively reduces plasma DOMS and CK levels in the bloodstream. [ABSTRACT FROM AUTHOR]

Changes in protein turnover play an important role in dynamic physiological processes, including skeletal muscle regeneration, which occurs as an essential part of tissue repair after injury. The inability of muscle tissue to recapitulate this regenerative process can lead to the manifestation of clinical symptoms in various musculoskeletal diseases, including muscular dystrophies and pathological atrophy. Here, we employed a workflow that couples deuterated water (2H2O) administration with mass spectrometry (MS) to systematically measure in-vivo protein turnover rates across the muscle proteome in 8-week-old male C57BL6/J mice. We compared the turnover kinetics of over 100 proteins in response to cardiotoxin (CTX) induced muscle damage and regeneration at unique sequential stages along the regeneration timeline. This analysis is compared to gene expression data from mRNA-sequencing (mRNA-seq) from the same tissue. The data reveals quantitative protein flux signatures in response to necrotic damage, in addition to sequential differences in cell proliferation, energy metabolism, and contractile gene expression. Interestingly, the mRNA changes correlated poorly with changes in protein synthesis rates, consistent with post-transcriptional control mechanisms. In summary, the experiments described here reveal the signatures and timing of protein flux changes during skeletal muscle regeneration, as well as the inability of mRNA expression measurements to reveal changes in directly measured protein turnover rates. The results of this work described here provide a better understanding of the muscle regeneration process and could help to identify potential biomarkers or therapeutic targets. [ABSTRACT FROM AUTHOR]

People with overweight or obesity preferred high-intensity interval training (HIIT) due to the time-efficiency and pleasure. However, HIIT leads to delayed onset muscle soreness (DOMS). The present study aimed to investigate the effects of omega-3 supplementation on DOMS, muscle damage, and acute inflammatory markers induced by cycling HIIT in untrained males with overweight or obesity. A randomized, double-blinded study was used in the present study. Twenty-four males with a sedentary lifestyle were randomly assigned to either receive omega-3 (O3) (4 g fish oil) or placebo (Con). Subjects consumed the capsules for 4 weeks and performed cycling HIIT at the 4th week. After 4 weeks-intervention, the omega-3 index of O3 group increased by 52.51% compared to the baseline. All subjects performed HIIT at 4th week. The plasma creatine kinase (CK) level of Con group increased throughout 48h after HIIT. While the CK level of O3 group increased only immediately and 24h after HIIT and decreased at 48h after HIIT. The white blood cell count (WBC) of Con group increased immediately after the HIIT, while O3 group did not show such increase. There was no change of CRP in both groups. O3 group had a higher reduction of calf pain score compared to Con group. O3 group also showed a recovery of leg strength faster than Con group. Omega-3 supplementation for 4 weeks lower increased CK level, reduced calf pain score, and recovery leg strength, DOMS markers after cycling HIIT. [ABSTRACT FROM AUTHOR]

Pre-exercise passive heating attenuates muscle damage caused by eccentric exercise in rats where the induction of heat shock proteins (HSPs) confers a myoprotective effect. We investigated whether pre-exercise hot water immersion (HWI) confers similar benefits in humans. Eleven recreational male athletes were immersed in 41°C water up to 60 min or until rectal temperatures reached 39.5°C. After a 6 h rest, the participants performed an eccentric downhill run for 1 h at −4% gradient to induce muscle damage. An endurance capacity test at 75% VO2max was conducted 18 h later. The control trial was similar except that participants were immersed at 34°C. Blood samples were collected to assess HSPs levels, creatine kinase, and lactate dehydrogenase activities. Plasma eHSP70 was higher post-immersion in HWI trials (1.3 ± 0.4 vs 1.1 ± 0.4; p = 0.005). Plasma eHSP27 was higher before (p = 0.049) and after (p = 0.015) endurance test in HWI. Leukocytic p-HSP27 was increased 18 h after HWI (0.97 ± 0.14 vs 0.67 ± 0.11; p = 0.04). Creatine kinase and lactate dehydrogenase activities were increased by 3-fold and 1.5-fold, respectively, after endurance test in HWI but did not differ across trials (p > 0.05). Mean heart rates were higher during eccentric run and endurance test in HWI as compared to control (p < 0.05). Endurance capacity was similar between trials (57.3 ± 11.5 min vs 55.0 ± 13.5 min; p = 0.564). Pre-exercise heating increased the expression of plasma eHSPs and leukocytic p-HSP27 but did not reduce muscle damage nor enhance endurance capacity. [ABSTRACT FROM AUTHOR]

Spirulina is a supplement with antioxidant and anti-inflammatory properties that may enhance performance and recovery after intense exercise. The present study aimed to investigate the effects of Spirulina Nigrita® on physical performance, and recovery markers after intense eccentric exercise in healthy moderately physically active volunteers. In a double-blind crossover design, participants were supplemented either with spirulina (42 mg Kg−1 BW per day) or a placebo for 15 days before conducting an eccentric exercise protocol using the non-dominant arm. A six-week washout period was required between conditions. Performance and mobility markers such as isometric peak torque (PTQ), ligament range of motion (ROM), and perceived muscle discomfort (VAS) were assessed and blood samples (CK, LDH) were obtained at 1, 24, 48, and 72 h post-exercise. No significant differences were noticed between the two conditions on any of the investigated markers, indicating that spirulina supplementation has no positive effect on isometric muscle performance or alleviation of exercise-induced muscle damage (EIMD) symptoms in the specific population. [ABSTRACT FROM AUTHOR]

PurposeThis brief report aimed to characterize inter-individual training responses following a single session of high-intense whole-body electromyostimulation (WB-EMS) using markers of muscle damage over a period of 72 h.MethodsTwelve healthy individuals (5 men, 7 women; 32.0 ± 7 years) participated in a single 20-minute high-intensity WB-EMS training session. Markers of muscle damage, creatine kinase (CK) and myoglobin (Mb), were assessed before and immediately after training, as well as at 1.5, 3, 24, 48 and 72 h post-exercise. Lactate levels were determined pre- and post-exercise.ResultsOverall, WB-EMS induced significant CK elevations, peaking at 72 h (18.358 ± 21.380 U/L; p

[Objective] To investigate the effect of β-hydroxy-β-methylbutyrate （HMβ） supplementation on muscle protection in taekwondo players during training. [Methods] 18 male subjects above the second level of the Taekwondo special Team who voluntarily participated in the experiment were recruited and divided into experimental and control groups （9 each） according to the conditions. The experimental group consumed one sachet （25 g/bag, the amount of HMβ added was 500 mg/bag） of HMβ-added milk powder before and after training （with a break of more than 30 min） in the morning and afternoon from Monday to Saturday, while the control group consumed the same amount of commercially available regular milk powder. Blood samples were collected before and after the intervention and on Monday mornings to analyze the changes in biochemical indicators, and quantitative tests of Taekwondo-specific abilities were performed before and after the experiment. [Results] Compared with the control group, the experimental group did not see significant changes in the pro-inflammatory factor interleukin-6, plasma glutamine levels were significantly increased （PPPβ supplementation during training can exert protective functions by reducing inflammation, improving immune function, maintaining muscle membrane stability, increasing nitrogen stores, and strengthening muscle remodeling ability, improving muscle adaptability to training to ensure their competitive status.

Exercise-Induced Muscle Damage (EIMD) is the disruption of skeletal muscle after high-intensity exercise, leading to decreased performance. Furthermore, it is a common condition following vigorous exercise, particularly in individuals unaccustomed to performance. This disruption results in a decrease in strength, muscle soreness, swelling, and the release of several cytokines, both inflammatory and anti-inflammatory. Symptoms of EIMD include Delayed-Onset Muscle Soreness (DOMS) and a loss of physical function. Therefore, this study aimed to investigate the effect of a 14-day administration of yacon leaves capsule supplementation on DOMS and inflammation post-EIMD. To achieve this, an experimental pretest and posttest control group design with a randomized control trial approach was adopted. A total of 32 Recreational male students of the Sports Science Universitas Negeri Surabaya were randomly and double-blindly assigned to either yacon capsule supplementation (n=16) or placebo (n=16) group. Participants were instructed to take a yacon capsule or placebo after breakfast for 14 days. The study groups were subjected to a muscle-damaging protocol consisting of 7 sets of 10 eccentric single-leg press repetitions on a leg press machine. DOMS and Interleukin 6 (IL-6) were determined at 0-h (baseline), 24-h, and 48-h post-exercise before and after 14-day supplementation periods. The results showed that DOMS and IL-6 serum increased at 24 hours post-EIMD when compared to baseline. Additionally, a significant reduction in both DOMS and IL-6 serum levels was observed within the yacon group compared to the placebo group (p

OBJECTIVES This study was performed to investigate the effects and mechanisms of kinesio taping on exercise-induced muscle damage and provide guidelines for field application. METHODS To review the literature, we searched PubMed, Web of Science, and Wiley Online Library using keywords including “kinesio taping,” “exercise-induced muscle damage,” “eccentric muscle contraction,” “delayed-onset muscle soreness (DOMS).” RESULTS Previous studies have shown that kinesio taping effectively reduces exercise-induced muscle damage (particularly DOMS). The ‘convolutions’ characteristics of kinesio taping are assumed to be the primary contributor to these results. Some mechanical or neurological mechanism may also exert a substantial effect. For field applications, the application period, tension, and type of KT interventions should be considered. CONCLUSIONS Kinesio taping may be a useful tool to promote recovery from exercise-induced muscle damage. Some aspects of kinesio-taping and its therapeutic mechanisms require further study.

Abstract Background Branched-chain amino acid (BCAA) supplementation is one of the most popular strategies used by the general population and athletes to reduce muscle soreness and accelerate the recovery process of muscle damage biomarkers after an intense exercise or training session. Objectives This systematic review and meta-analysis investigated the effects of BCAA supplementation on muscle damage biomarkers and muscle soreness after exercise-induced muscle damage (EIMD). Methods The systematic literature search for randomized controlled trials was conducted using seven databases, up to September 13th, 2022. The eligibility criteria for selecting studies were as follows: studies performed on healthy active participants, using BCAA at least once, controlled with a placebo or control group, performing resistance or endurance exercises, and followed up at least once post-EIMD. The methodological quality of the studies was assessed using the “SIGN RCT checklist”. Random-effects meta-analyses were processed to compute the standardized mean difference (Hedges’ g). Meta-regression analyses were completed with daily and total dosage and supplementation as continuous moderator variables. Results Of the 18 studies included in this meta-analysis, 13 were of high quality and five were of acceptable quality. Our results revealed BCAA supplementation elicits a significant effect on reducing creatine kinase (CK) levels immediately (g = − 0.44; p = 0.006) and 72 h (g = − 0.99; p = 0.002), but not 24 h, 48 h, and 96 h post-EIMD. Additionally, a significant effect on delayed onset of muscle soreness (DOMS) was identified at 24 h (g = − 1.34; p

The aim of this study is to investigate the effects of wearable local vibration therapy (VT) on muscle soreness, joint position sense, and dynamic balance in recovery after squat exercise. Twenty males (age: 22.25±1.97 years) participated in the study. Muscle soreness, joint position sense, and dynamic balance were evaluated before exercise, 24 and 48 hours after exercise. All participants performed six sets of 10 repetitions of squat exercises. VT was applied to one thigh of the participants randomly for 10 minutes after exercise, and the other thigh was determined as the control. The muscle soreness increased significantly for VT (p.05). No significant difference was found between VT and control (p>0.05). No significant difference was found after exercise at knee joint position sense for both conditions (p>.05). No significant difference was observed between VT and control (p>.05). There was a significant difference between before exercise and 48 hours after exercise at anterior direction of the modified Star Excursion Balance Test for VT (p=.033). A significant difference was found between before exercise and 24 hours after exercise at posteromedial (p=.012) direction for VT. There was only significant difference at posteromedial (p=.028) direction at 24 hours after exercise between VT and control. The wearable local VT after squat exercise did not affect muscle soreness and knee joint position sense. However, local VT contributed to the improvement of dynamic balance.

Abstract Background Studies have investigated the effects of training under hypoxia (HYP) after several weeks in a male population. However, there is still a lack of knowledge on the acute hypoxic effects on physiology and muscle recovery in a female population. Methods This randomized-controlled trial aimed to investigate the acute effects of muscle damaging exercise, performed in HYP and normoxia (CON), on physiological responses and recovery characteristics in healthy females. Key inclusion criteria were recreationally active female participants between the age of 18 to 35 years without any previous surgeries and injuries, whilst key exclusion criteria were acute pain situations, pregnancy, and medication intake. The females conducted a muscle-damaging protocol, comprising 5 × 20 drop-jumps, in either HYP (FiO2: 12%) or CON (FiO2: 21%). Physiological responses, including capillary oxygenation (SpO2), muscle oxygenation (SmO2), heart rate (HR), core- (Tcore) and skin- (Tskin) temperature were assessed at the end of each exercise set. Recovery characteristics were quantified by taking venous blood samples (serum creatine-kinase [CK], C-reactive protein [CRP] and blood sedimentation rate [BSR]), assessing muscle swelling of the quadriceps femoris muscle, maximum voluntary isometric contraction (MVIC) of the knee extensor muscles, countermovement jump (CMJ) performance and muscle soreness ratings (DOMS) at 24-, 48- and 72-hrs post-exercise. Results SpO2 (HYP: 76.7 ± 3.8%, CON: 95.5 ± 1.7%, p 0.05). There were also no differences detected for any recovery variable (CK, CRP, BSR, MVIC, CMJ, and DOMS) during the 72-hrs follow-up period between HYP and CON (all p > 0.05). Conclusion In conclusion, our results showed that muscle damaging exercise under HYP leads to reduced capillary and muscle oxygenation levels compared to normoxia with no difference in inflammatory response and muscle recovery during 72 h post-exercise. Trial registration NCT04902924, May 26th 2021.

Abstract Background Recently, genetic predisposition to injury has become a popular area of research and the association between a few single nucleotide polymorphisms (SNPs) and the susceptibility to develop musculoskeletal injuries has been shown. This pilot study aimed to investigate the combined effect of common gene polymorphisms previously associated with muscle injuries in Italian soccer players. Results A total of 64 Italian male top football players (age 23.1 ± 5.5 years; stature 180.2 ± 7.4 cm; weight 73.0 ± 7.9 kg) were genotyped for four gene polymorphisms [ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739), COL5A1 C > T (rs2722) and MCT1 c.1470A > T (rs1049434)]. Muscle injuries were gathered for 10 years (2009–2019). Buccal swabs were used to obtain genomic DNA, and the PCR method was used to genotype the samples. The combined influence of the four polymorphisms studied was calculated using a total genotype score (TGS: from 0 to 100 arbitrary units; a.u.). A genotype score (GS) of 2 was assigned to the “protective” genotype for injuries, a GS of 1 was assigned to the heterozygous genotype while a GS of 0 was assigned to the “worst” genotype. The distribution of genotype frequencies in the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and MCT1 c.1470A > T (rs1049434) polymorphisms was different between non-injured and injured football players (p = 0.001; p = 0.016 and p = 0.005, respectively). The incidence of muscle injuries was significantly different among the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and COL5A1 C > T (rs2722) genotype groups, showing a lower incidence of injuries in the “protective” genotype than “worse” genotype (ACE, p

Purpose: The authors investigated whether far-infrared radiation (FIR) lamp therapy would reduce muscle damage and enhance recovery from multiple soccer-match-related running activities. Methods: Twenty-four elite female soccer players (20–24 y) were assigned into a FIR or a sham treatment group (n = 12/group). They performed a daily 90-minute Loughborough Intermittent Shuttle Test (LIST) for 6 consecutive days. Maximal voluntary contraction torque of the knee extensors (KEs) and flexors, muscle soreness, plasma creatine kinase activity, countermovement jump, and several other performance measures (eg, 30-m dash, Yo-Yo Intermittent Recovery Test Level 1) were taken before the first LIST, 1 hour after each LIST, and 24, 48, 72, 96, and 120 hours after the last LIST. All participants received a 30-minute FIR or sham treatment on KEs and knee flexors, respectively, at 2 hour after each LIST and 25, 49, 73, and 97 hours after the last LIST. Results: All measures changed significantly (P <.05) at 1 hour after the first LIST without difference (P >.05) between groups. Maximal voluntary contraction torque (eg, the largest decrease of KE for FIR: 13% [4%], sham: 25% [5%]), countermovement jump height (4% [3%] vs 14% [4%]), and other performance measures (eg, Yo-Yo Intermittent Recovery Test: 11% [5%] vs 26% [5%]) decreased less, and peak muscle soreness (eg, KE: 26 [9] vs 51 [18] mm) and plasma creatine kinase activity (172 [32] vs 1289 [610] IU/L) were smaller for the FIR than for the sham group (P <.05), and they returned to the baseline earlier (P <.05) for the FIR group. Conclusions: These results suggest that the FIR therapy provided potent effects on reducing accumulated muscle damage and enhancing recovery. [ABSTRACT FROM AUTHOR]

ABSTRACTCurcumin is a natural polyphenolic compound exerting antioxidative and anti-inflammatory effects on various tissues, including muscles. Nevertheless, its clinical usage has been limited because of its poor bioavailability. Thus, highly bioavailable curcumin, such as Theracurmin (CR-033P) composed of 36% crystalline curcumin, has been developed. This study investigated the antioxidant activity and muscle-protective effect of Theracurmin Super (TS-P1), a new formulation with 36% amorphous curcumin. TS-P1 and CR-033P demonstrated antioxidant activity in vitro. Compared with pure curcumin, orally administered TS-P1 or CR-033P (16.7 or 50 mg per kg of body weight) at one-third dose inhibited the elevation of plasma lactate dehydrogenase and creatine kinase levels in a mouse downhill running model, indicating superior muscle-protective effect. Particularly, TS-P1 showed better or equivalent effectiveness in restoring the activity of antioxidant enzymes including glutathione peroxidase and catalase, and in suppressing inflammatory responses. Therefore, formulation with amorphous curcumin is a promising strategy for curcumin-based supplements.