Prevent Muscle Damage Research Articles

Mechanisms Underlying Menstrual Cycle Effects on Exercise Performance: A Scoping Review

This scoping review aims to provide a comprehensive overview of biological mechanisms underlying the menstrual cycle’s impact on various performance-determining anatomical and physiological parameters. It is intended to identify the various proposed vital concepts and theories that may explain performance changes following hormonal fluctuations. The review was performed following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews protocol. A framework of six groups was built such as skeletal muscle physiology, muscle damage, tendons and ligaments, neuromuscular control, cardiovascular system, and exercise metabolism to cluster studies thematically and to specify the concept of “performance.” Original research studies published between 1970 and 2021 that were conducted with a naturally menstruating population were considered. Changes in performance regarding the menstrual cycle phase were crucial for inclusion. Topic-specific reviews and systematic reviews were included if they addressed the impact of female steroid hormones on any structure or part of the human body. The review indicates that the impact of estrogen and progesterone is primarily responsible for observed changes in athletic performance during the menstrual cycle. Estrogen seems capable of fostering protein synthesis, diminishing collagen metabolism, preventing muscle damage due to its antioxidant effects, and restraining inhibitory, while promoting excitatory, control by interacting with neurotransmitters. Progesterone is assumed to increase thermoregulation and enhance ventilatory drive by interacting with hypothalamic pathways and may further amplify inhibitory control by interacting with neurotransmitters. The female steroid hormones and the endocrinologic system collaborate in complex interrelationships with biological systems to maintain homeostasis. However, proposed mechanisms are often derived from animal studies and studies conducted in vitro and still remain to be proven true in the human regularly menstruating population. In the future, it is crucial to rely on studies that followed the methodology for cycle monitoring recommendations thoroughly. Otherwise, it is not possible to determine whether hormonal fluctuations cause observed changes in performance or not.

Ubiquinol Short-Term Supplementation Prior to Strenuous Exercise Improves Physical Performance and Diminishes Muscle Damage.

The benefits of physical exercise on health are diminished when it is non-planned, strenuous, or vigorous, which causes an increase in oxygen consumption and production of free radicals, particularly serious at the muscular level. Ubiquinol could help achieve an antioxidant, anti-inflammatory, and ergogenic effect. The aim of this study is to evaluate whether a supplementation of ubiquinol during a short period could have a positive effect on muscle aggression, physical performance, and fatigue perception in non-elite athletes after high intensity circuit weight training. One hundred healthy and well-trained men, (firemen of the Fire Department of Granada) were enrolled in a placebo-controlled, double-blinded, and randomized study, and separated into two groups: the placebo group (PG, n = 50); and the ubiquinol group (UG, n = 50), supplemented with an oral dose. Before and after the intervention, data related to the number of repetitions, muscle strength, and perceived exertion, as well as blood samples were collected. An increase was observed in the UG regarding average load and repetitions, revealing an improvement in muscle performance. Ubiquinol supplementation also reduced muscle damage markers, showing a protective effect on muscle fibers. Therefore, this study provides evidence that ubiquinol supplementation improves muscle performance and prevents muscle damage after strenuous exercise in a population of well-trained individuals who are not elite athletes.

Minced muscle autografting improves bone healing but not muscle function in a porcine composite injury model.

Composite tissue injuries (CTIs) in extremities include segmental bone defects (SBDs) and volumetric muscle loss. The objective of this study was to determine if skeletal muscle autografting with minced muscle grafts (MMGs) could improve healing in an SBD and improve muscle function in a porcine CTI model that includes an SBD and adjacent volumetric muscle loss injury. Adult Yucatan Minipigs were stratified into three groups including specimens with an isolated SBD, an SBD with volumetric muscle loss (CTI), and an SBD with volumetric muscle loss treated with MMG (CTI + MMG). Bone healing was quantified with serial x-rays and postmortem computed tomography scanning. Muscle function was quantified with a custom in vivo force transducer. Muscle tissue content was determined by biochemical analyses and histology. Anterior cortex-modified Radiographic Union Score for Tibia fractures (mRUSTs) decreased from 2.7 to 1.9 (p = 0.003) in CTI versus SBD animals. MMG improved anterior mRUST scores to 2.5 in CTI + MMG specimens (p = 0.030 compared to CTI specimens) and overall mRUST scores increased from 9.4 in CTI specimens to 11.1 in CTI + MMG specimens (p = 0.049). Residual strength deficits at euthanasia were 42% in SBD (p < 0.001), 44% in CTI (p < 0.001), and 48% in CTI + MMG (p < 0.001) compared to preoperative values. There were no differences in strength deficits between the three groups. Biochemical and histologic analyses demonstrated scattered differences between the three groups compared to contralateral muscle. MMG improved bone healing. However, the primary cause of muscle dysfunction and biochemical changes was the presence of an SBD. Clinical significance: Early mitigation of SBDs may be necessary to prevent muscle damage and weakness in patients sustaining composite extremity trauma.

A fatigue assessment method based on attention mechanism and surface electromyography

Surface electromyography (sEMG) signals can be used to quantitatively assess muscle fatigue, thereby directly and objectively reflecting the functional state of neuromuscular activity. Effective fatigue diagnosis can prevent muscle damage, thereby improving the safety of rehabilitation exercise. Traditional fatigue diagnosis has certain limitations, including strong subjectivity and poor accuracy. This paper designs a sEMG signals acquisition circuit and collects the sEMG signals of the upper limb biceps brachii and triceps brachii in the force-relaxation state in a dual-channel form. Muscle fatigue classification assessment using Dynamic Time Warping-K Nearest Neighbor (DTW-KNN) and three deep learning algorithms. The experimental results show that compared with traditional machine learning algorithms, deep learning algorithm can achieve higher accuracy and time efficiency. In addition, this study introduces an attention mechanism to dynamically and reasonably assign network weights to achieve high level feature learning. The Attention-Long Short-Term Memory (Attention Based LSTM) neural network achieves 93.5% assessment accuracy with a time overhead of only 3.73s, allowing for real-time assessment of muscle fatigue.

지연성 근통증 유발 후 Ibuprofen 투여가 최대근력 및 근 손상 지표에 미치는 영향

This study aimed to investigate the effects of Ibuprofen supplement on delayed onset muscle soreness(DOMS) by analyzing the maximum muscle strength and indicators of muscle damꠓ age. Eighteen men with majors in physical education were assigned to the Ibuprofen group and placebo group in a double-blinded design, and repeated measurements were conducted. DOMS was induced with an isokinetic exercise. Following Ibuprofen administration, the changes in the knee extension peak torque, flexion peak torque, creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were analyzed. The administration of Ibuprofen inhibits the reduction of the extension peak torque and elevation of CK concentrations. Therefore, Ibuprofen might be administered as a supplement to maintain the muscle strength and prevent muscle damage.

Development of Automatic Controlled Walking Assistive Device Based on Fatigue and Emotion Detection

The world’s aging population is increasing. The number of elderly individuals having walking impairments is also increasing. Adequate exercise is becoming necessary for them. Therefore, several walking assistive devices have been developed or are under development. However, elderly individuals may have low motivation for exercising, or they may experience physical damage by excessive fatigue. This study proposed a method to enable elderly individuals to exercise with a positive emotion and prevent damage such as muscle fatigue. We proposed a 3D human condition model to control the walking assistive device. It includes the arousal, pleasure, and fatigue dimensions. With regard to the arousal and pleasure dimensions, we used heartbeat and electromyography (EEG) signals to train a deep neural network (DNN) model to identify human emotions. For fatigue detection, we proposed a method based on near-infrared spectroscopy (NIRS) to detect muscle fatigue. All the sensors are portable. This implies that it can be used for outdoor activities. Then, we proposed a walking strategy based on a 3D human condition model to control the walking assistive device. Finally, we tested the effectiveness of the automatic control system. The wearing of the walking assistive device and implementation of the walking strategy can delay the fatigue time by approximately 24% and increase the walking distance by approximately 16%. In addition, we succeeded in visualizing the distribution of emotion during each walking method variation. It was verified that the walking strategy can improve the mental condition of a user to a certain extent. These results showed the effectiveness of the proposed system. It could help elderlies maintain higher levels of motivation and prevent muscle damage by walking exercise, using the walking assistive device.

Valorization of whey proteins and beetroot peels to develop a functional beverage high in proteins and antioxidants.

Adequate protein and antioxidant intake are crucial for everyone, particularly athletes, to promote muscle performance and prevent muscle damage. Whey proteins are high-quality proteins with high digestibility and bioavailability; beetroot peels are an abundant antioxidant source. The present study was designated to develop a functional beverage based on mixing whey protein isolate (5%) with different concentrations of beetroot peel water extract (1, 2.5, and 5%) and flavored with strawberries puree (5%). In addition, we examined the stability of the physicochemical parameters and the bioactive components of the beverages during cold storage (4°C) for 14 days. Whey protein isolates enriched the juices with stable protein content during the storage (4.65-4.69%). Besides, the extract revealed a concentration-dependent effect on the bioactive components, the antioxidant activity, and the microbial load of the juices; it distinguished the fresh juices by high betalains and nitrate content, 87.31-106.44 mg/L and 94.29-112.59 mg/L, respectively. Beverages with 2.5% peel extract (T2) had the preferable sensory attributes compared to control and other treatments. On day 0, phenolics and flavonoids increased in T2 by 44 and 31% compared to the control, which elevated the scavenging activity of the juice (T2) (P < 0.05). At the end of the storage period (14 days), phenolics and flavonoids of T2 recorded their lowest values, 26.23 and 21.75 mg/mL, respectively. However, they stood higher than phenolics (22.21 mg/mL) (p < 0.05) and flavonoids (18.36 mg/mL) (p > 0.05) of control. Similarly, betalains degraded by 45% to reach 47.46 mg/L in T2, which reduced the redness (a*) and increased the yellowness (b*) values. Consequently, whey/strawberry/beetroot peel (5: 5: 2.5 w/v/w) in d.H2O is a functional beverage that provides the body with a high-quality protein and a considerable amount of antioxidants.

The Effect Of Acute Jamu Kunyit Asam After Strenuous Physical Exercise On Creatine Kinase Levels

Strenuous physical exercise can trigger muscle damage causing an increase in creatine kinase levels. One of the strategies to prevent muscle damage is to consume antioxidants and anti-inflammatory. Jamu Kunyit Asam is known to have antioxidant and anti-inflammatory activity. The aim of this study was to determine the effect of acutely giving Jamu Kunyit Asam on creatine kinase levels after strenuous physical exercise. The research sample used 20 trained males. The sample was divided into two groups (Experiment = 10; Placebo = 10). The pre-test was done by checking creatine kinase levels before engaging in strenuous physical exercise. After doing strenuous physical exercise by running on a treadmill with an intensity of 90-100% for 30 minutes, the experimental group was given 250 ml of Jamu Kunyit Asam every day for 3 days, while the control group was given a placebo drink. Creatine kinase levels were measured immediately, 24 hours, 48 hours, and 72 hours after strenuous physical exercise. The results showed that CK levels decreased significantly 24 hours, 48 hours and 72 hours after strenuous physical exercise in the Jamu Kunyit Asam group compared to the placebo group (p&lt;0.05). The conclusion of this study is that giving Jamu Kunyit Asam acutely after doing strenuous physical exercise can reduce creatine kinase levels in trained male athletes. Acute Jamu Kunyit Asam supplementation in this study can help reduce muscle damage due to strenuous physical exercise through nutritional interventions.

Antifatigue effect of naringin on improving antioxidant capacity and mitochondrial function and preventing muscle damage.

The aim of this study was to explore effects of naringin (Nar) on antifatigue ability; the weight-loaded and non-loading swimming tests were performed. Compared with the control group, dietary supplementation of Nar significantly prolonged the weight-loaded swimming time to exhaustion of mice (P < 0.01). Nar significantly reduced the serum lactic acid (LD) level (P < 0.05) and lactate dehydrogenase (LDH) activity (P < 0.001), while increased the serum non-esterified free fatty acids (NEFA) level (P < 0.001). In addition, Nar significantly increased the liver glycogen and muscle glycogen contents (P < 0.05) and the phosphoenolpyruvate carboxykinase (PEPCK) (P < 0.01) and glucokinase (GCK) mRNA levels (P < 0.001) in liver and gastrocnemius (GAS) muscle. Furthermore, Nar significantly improved the antioxidant capacity, mitochondrial function, and muscle mitochondrial fatty acid β-oxidation (P < 0.05), and decreased inflammation and muscle damage-related gene expression (P < 0.05). These findings suggested that Nar can improve antifatigue effect by enhancing antioxidant capacity and mitochondrial function and preventing muscle damage.

운동경험이 없는 남성의 저항성 운동강도 차이가 근 손상 지표, 근력 및 근 비대 효과에 미치는 영향

This study was conducted to identify the intensity of resistance exercise that can improve muscle strength and hypertrophy while preventing muscle damage in untrained men in their 20s. Thirty men were divided into control group(n=10), low-load resistance exercise group(n=10), and high-load resistance exercise group(n=10). Resistance exercise of LLRG was performed with 40% 1RM, 3 sets, and repetitions per set until spontaneous muscle failure occurred. Resistance exercise of HLRG was performed with 80% 1RM, 3 sets, and repetitions per set until spontaneous muscle failure occurred. Resistance exercise was performed 3 times a week for a total of 12 weeks. After the end of the experiment, repeated measures ANOVA was performed to analyze the changes in the muscle damage indicator, muscle strength, and muscle hypertrophy. The results were as follows. Results of muscle damage indicator showed no significant difference in LLRG, but LDH, CK, Myoglobin, and AST significantly increased in HLRG after 12 weeks. And the result of muscle strength, both LLRG and HLRG were significantly increased, but HLRG was increased more than LLRG. In addition, the results of muscle mass were significantly increased to a similar level for both LLRG and HLRG. Summarizing the above results, it is judged that resistance exercise of 40% 1RM level of exercise intensity during the initial exercise plan for subjects without exercise experience can prevent muscle damage and increase muscle hypertrophy.

Oridonin attenuates hind limb ischemia–reperfusion injury by modulating Nrf2-mediated oxidative stress and NLRP3-mediated inflammation

Ethnopharmacological relevanceOridonin (Ori), extracted from Isodon rubescens (Hemsl.) H.Hara, is a well-known traditional Chinese herbal medicinal product that possesses antioxidant and anti-inflammatory activities. Oxidative stress and inflammation are the main pathophysiological mechanisms in hindlimb IR injury. However, whether Ori has a protective effect on hind limb IR injury is unknown. Aim of the studyThe present study was designed to determine the effect of Ori on hindlimb IR injury and its relationship with oxidative stress and inflammation. Materials and methodsThe hind limb IR injury model in mice was used to evaluate the protective effect and related mechanisms of Ori. Forty-eight C57BL/6 mice (n = 12 per group) were randomly divided into four groups: Sham group; IR group; IR + Ori (10 mg/kg) group and IR + Ori (20 mg/kg) group. Mice in the IR and IR + Ori groups were subjected to hindlimb IR injury, while mice in the Sham group were subjected to no hindlimb IR injury. HE staining, Masson's staining, TTC staining, DHE staining, TUNEL staining, western blotting analysis and quantitative real-time PCR were employed to explore the mechanisms by which Ori exerts a protective effect on a classical hindlimb IR model in mice. ResultsWe found that Ori pretreatment prevented muscle damage and decreased cell apoptosis levels compared with the vehicle control. Moreover, the SOD2, CAT, MDA and ROS levels in muscle showed that Ori could significantly reduce oxidative stress in hindlimb IR mice, while the IL-1β and TNF-α levels in muscle showed that Ori could significantly attenuate IR-induced inflammation. We also found that Ori could increase the expression of Nrf2 and its downstream protein HO-1 and inhibit the expression levels of NLRP3-related proteins (NLRP3, ASC and Caspase-1) in vivo. ConclusionsOur study suggested that Ori has a protective effect on hindlimb IR injury, which may be related to Nrf2-mediated oxidative stress and NLRP3-mediated inflammasome activation.

Relationship Between Physical Activity Level and Muscle Markers in a Population-Based Sample of Children and Adolescents

Objectives: The study aimed was to investigate the relationship between physical activity (PA) levels and muscle markers in healthy children and adolescents. Methods: This cross-sectional study was conducted in 2020 among school students from Isfahan, Iran. Using cluster sampling, 159 students aged 7 to 18 years were selected. In addition to the physical examination, the PA level was assessed using a valid questionnaire. The serum levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), and alanine aminotransferase (ALT) were measured. Statistical analysis was performed using the Pearson correlation test. Results: The samples included 79 girls and 80 boys with a mean age (standard deviation) of 12.72 (3.06) years and a mean body mass index of 18.30 (3.70) kg/m2. The mean AST and CPK were significantly higher in boys than in girls (P &lt; 0.05). Participants with higher PA levels had significantly lower LDH and ALT than other participants (-0.20, P = 0.003, and 0.044 P = 0.295, respectively). There was no significant relationship between PA level and muscle enzyme levels. Conclusions: The findings of this study indicated that higher PA level was associated with lower serum muscle markers other than LDH. This suggests that the best types of PA for children and adolescents are those activities with rest sets to prevent muscle damage.

Oxidative Stress, Inflammation, and Activators of Mitochondrial Biogenesis: Tempol Targets in the Diaphragm Muscle of Exercise Trained-mdx Mice.

The mdx mouse phenotype aggravated by chronic exercise on a treadmill makes this murine model more reliable for the study of muscular dystrophy. Thus, to better assess the Tempol effect on dystrophic pathways, the analyses in this study were performed in the blood samples and diaphragm muscle from treadmill trained adult (7–11-weeks old) mdx animals. The mdx mice were divided into three groups: mdxSed, sedentary controls (n = 28); mdxEx, exercise-trained animals (n = 28); and mdxEx+T, exercise-trained animals with the Tempol treatment (n = 28). The results demonstrated that the Tempol treatment promoted muscle strength gain, prevented muscle damage, reduced the inflammatory process, oxidative stress, and angiogenesis regulator, and up regulated the activators of mitochondrial biogenesis. The main new findings of this study are that Tempol reduced the NF-κB and increased the PGC1-α and PPARδ levels in the exercise-trained-mdx mice, which are probably related to the ability of this antioxidant to scavenge excessive ROS. These results reinforce the use of Tempol as a potential therapeutic strategy in DMD.

The Effect of Acute Beetroot Juice Supplementation After Strenuous Physical Activity on Creatine Kinase Levels

Strenuous physical activity can cause muscle damage which is marked by an increase in creatine kinase levels. One of the strategies to prevent muscle damage is to consume antioxidants and anti-inflammatory. Beetroot (Beta vulgaris L.) is known to have antioxidant and anti-inflammatory activity. The aim of this study was to determine the effect of acutely giving beetroot juice on creatine kinase levels after strenuous physical activity. The research sample used 20 trained males. The sample was divided into two groups (Experiment = 10; Placebo = 10). The pre-test was done by checking creatine kinase levels before engaging in strenuous physical activity. After doing strenuous physical activity by running on a treadmill with an intensity of 90-100% for 30 minutes, the experimental group was given 300 ml of beetroot juice (BRJ) every day for 3 days, while the control group was given a placebo drink. Creatine kinase levels were measured immediately, 24 hours, 48 hours, and 72 hours after strenuous physical activity. The results showed that CK levels decreased significantly 24 hours, 48 hours and 72 hours after strenuous physical activity in the BRJ group compared to the placebo group (p <0.05) The conclusion of this study is that giving BRJ acutely after doing strenuous physical activity can reduce creatine kinase levels in trained male athletes. Acute JBR supplementation in this study can help reduce muscle damage due to strenuous physical exercise through nutritional interventions

Effects of branched-chain amino acid supplement on knee peak torque and indicators of muscle damage following isokinetic exercise-induced delayed onset muscle soreness

[Purpose] This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplement on delayed onset muscle soreness (DOMS) by analyzing the maximum muscle strength and indicators of muscle damage.[Methods] Twelve men with majors in physical education were assigned to the BCAA group and placebo group in a double-blinded design, and repeated measurements were conducted. DOMS was induced with an isokinetic exercise. Following BCAA administration, the changes in the knee extension peak torque, flexion peak torque, aspartate aminotransferase (AST), creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were analyzed. The maximum knee muscle strength was measured at the baseline (pre-D0) following BCAA administration for 5 days before exercise (-D5, -4D, -3D, -2D, -1D). In contrast, the post-treatment measurements (D3) were recorded after BCAA administration for 3 days (post-D0, D1, D2). Blood samples were obtained before (pre-D0), immediately after (post-D0), 24 h (D1), 48 h (D2), and 72 h (D3) after the exercise to analyze the indicators of muscle strength. BCAA was administered twice daily for 8 days (5 days and 3 days before inducing DOMS and during the experimental period, respectively).[Results] There was no difference in the flexion peak torque between the groups. However, the BCAA group showed a significantly higher extension peak torque at D3 (second isokinetic exercise), compared to the placebo group (p<.05). There was no difference in AST changes between the groups. Nonetheless, the CK and LDH were significantly reduced in the BCAA group, compared to the placebo group. There was no correlation between the extension peak torque and flexion peak torque. However, the CK and LDH increased proportionately in DOMS. Moreover, their concentrations significantly increased with a decreasing peak torque (p<.01).[Conclusion] An exercise-induced DOMS results in a decrease in the peak torque and a proportional increase in the CK and LDH concentrations. Moreover, the administration of BCAA inhibits the reduction of the extension peak torque and elevation of CK and LDH concentrations. Therefore, BCAA might be administered as a supplement to maintain the muscle strength and prevent muscle damage during vigorous exercises that may induce DOMS in sports settings.

High coenzyme Q10 plasma levels improve stress and damage markers in professional soccer players during competition.

Ubiquinol, the reduced form of Coenzyme Q10 (CoQ10), is a key factor in bioenergetics and antioxidant protection. During competition, professional soccer players suffer from considerable physical stress causing high risk of muscle damage. For athletes, supplementation with several antioxidants, including CoQ10, is widely recommended to avoid oxidative stress and muscle damage. We performed an observational study of plasma parameters associated with CoQ10 levels in professional soccer players of the Spanish First League team Athletic Club de Bilbao over two consecutive seasons (n=24-25) in order determine their relationship with damage, stress and performance during competition. We analyzed three different moments of the competition: preterm, initial phase and mid phase. Metabolites and factors related with stress (testosterone/cortisol) and muscle damage (creatine kinase) were determined. Physical activity during matches was analyzed over the 2015/16 season in those players participating in complete matches. In the mid phase of competition, CoQ10 levels were higher in 2015/16 (906.8±307.9 vs. 584.3±196.3 pmol/mL, p=0.0006) High levels of CoQ10 in the hardest phase of competition were associated with a reduction in the levels of the muscle-damage marker creatine kinase (Pearsons' correlation coefficient (r)=-0.460, p=0.00168) and a trend for the stress marker cortisol (r=-0.252, p=0.150). Plasma ubiquinol was also associated with better kidney function (r=-0.287, p=0.0443 for uric acid). Furthermore, high CoQ10 levels were associated with higher muscle performance during matches. Our results suggest that high levels of plasma CoQ10 can prevent muscle damage, improve kidney function and are associated with higher performance in professional soccer players during competition.

Low-Dose of β-Hydroxy-β-Methylbutyrate (HMB) Alleviates Muscle Strength Loss and Limited Joint Flexibility Following Eccentric Contractions

Abstract Objectives The excessive exercise including eccentric contractions (ECCs) cause the reduction of maximal strength, limitation of range of motion (ROM), developed muscle soreness, and muscle swelling for several days from immediately after exercise. Therefore, it is important to promote the recovery of muscle damage and minimize decreases in muscle function and muscle soreness after exercise. We recently examined the effects of 2- and 4-week β-hydroxy-β-methylbutyrate (HMB) supplementation (3 g/day) on ECCs-induced muscle damage. As the result, both the 2- and 4-week treatments decreased muscle strength reduction, ROM, and muscle swelling. However, the optimal dose of HMB required for decreasing muscle damage remains unknown. Therefore, this study investigated the supplemental effect of low-dose HMB on muscle damage after ECCs of human elbow flexor muscles. Methods Twenty untrained men (age, 21.0 ± 1.3 years) were completed the double-blind, placebo-controlled, parallel design study. The subjects were randomly assigned to the ingestion of HMB supplement (HMB, n = 10) or placebo group (PL, n = 10). After the subjects of 1.5 g HMB or placebo pills per day for 2 weeks, they performed six sets of 10 ECCs at 100% maximal voluntary contraction (MVC) using dumbbell. Changes in MVC torque, ROM, upper arm circumference, and muscle soreness were assessed before, immediately after, 1, 2, 3, and 5 days after exercise. Results The MVC torque was significantly higher in the HMB than in the PL group immediately after (HMB, −56.8%; PL, −67.1%) as well as 3 (HMB: −25.5%, PL: −48.7%) and 5 (HMB: −22.5%, PL: −44.0%) days after performing ECCs (p &amp;lt; 0.05). Additionally, the ROM was significantly higher in the HMB than in the PL group immediately after (HMB, −29.8%; PL, −50.5%) and 5 (HMB: −26.1%, PL: −43.3%) days after performing ECCs (p &amp;lt; 0.05). However, no between-group differences were observed in upper arm circumference, and muscle soreness. Conclusions The results demonstrated that 1.5 g/day HMB significantly inhibits the reduction in muscle strength and ROM after ECCs. In addition, 1.5 g/day HMB has no effect on muscle soreness, swelling, or stiffness. We conclude that 1.5 g/day of HMB supplementation plays a role in preventing muscle damage after performing ECCs, even if the effects are limited. Funding Sources The present study was supported by a research funding by Kobayashi Perfumery Co., Ltd.

Neuromuscular Taping Decompression Techniques Fail to Prevent Muscle Damage After Eccentric Movement Activity

Eccentric activity is a type of activity facilitated by the addition of one or several muscles and often leaves the effects of pain even damage to muscle cells. The study aimed to determine the effect of the application of neuromuscular taping decompression techniques to muscle damage after eccentric movement activity. The type of research conducted is experimental research with post test only with control group design. Fourteen samples were selected from non-athlete populations at SMAN 1 Driyorejo based on consecutive sampling techniques and then divided into two groups randomly. Intervention of neuromuscular taping decompression techniques was given to the treatment group before performing eccentric movement activities. The elbow shoulder-extension flexion movement by holding 9% weight in 20 seconds was chosen as the protocol of eccentric movement activity. Measuring indicators of muscle damage using a serum Ck muscle examination 6 hours after rest. The results of the independent t-test showed no significant difference in the variable of muscle damage (p&gt; 0.05). It was concluded from this study that the neuromuscular taping decompression technique failed to prevent muscle damage after eccentric movement activity.

Characterization of surface electromyography signals of biceps brachii muscle in fatigue using symbolic motif features.

Exercise-induced muscle damage is a condition which results in the loss of muscle function due to overexertion. Muscle fatigue is a precursor of this phenomenon. The characterization of muscle fatigue plays a crucial role in preventing muscle damage. In this work, an attempt is made to develop signal processing methods to understand the dynamics of the muscle's electrical properties. Surface electromyography signals are recorded from 50 healthy adult volunteers under dynamic curl exercise. The signals are preprocessed, and the first difference signal is computed. Furthermore, ascending and descending slopes are used to generate a binary sequence. The binary sequence of various motif lengths is analyzed using features such as the average symbolic occurrence, modified Shannon entropy, chi-square value, time irreversibility, maximum probability of pattern and forbidden pattern ratio. The progression of muscle fatigue is assessed using trend analysis techniques. The motif length is optimized to maximize the rho value of features. In addition, the first and the last zones of the signal are compared with standard statistical tests. The results indicate that the recorded signals differ in both frequency and amplitude in both inter- and intra-subjects along the period of the experiment. The binary sequence generated has information related to the complexity of the signal. The presence of more repetitive patterns across the motif lengths in the case of fatigue indicates that the signal has lower complexity. In most cases, larger motif length resulted in better rho values. In a comparison of the first and the last zones, most of the extracted features are statistically significant with p < 0.05. It is observed that at the motif length of 13 all the extracted features are significant. This analysis method can be extended to diagnose other neuromuscular conditions.

Surface properties affect the interplay between fascicles and tendinous tissues during landing.

Muscle-tendon units are forcefully stretched during rapid deceleration events such as landing. Consequently, tendons act as shock absorbers by buffering the negative work produced by muscle fascicles likely to prevent muscle damage. Landing surface properties can also modulate the amount of energy dissipated by the body, potentially effecting injury risk. This study aimed to evaluate the influence of three different surfaces on the muscle-tendon interactions of gastrocnemius medialis (GM), and vastus lateralis (VL) during single- and double-leg landings from 50cm. Ultrasound images, muscle activity and joint kinematics were collected for 12 participants. Surface testing was also performed, revealing large differences in mechanical behavior. During single-leg landing, stiffer surfaces increased VL fascicle lengthening and velocity, and muscle activity independent of joint kinematics while GM length changes showed no difference between surfaces. Double-leg landing resulted in similar fascicle and tendon behavior despite greater knee flexion angles on stiffer surfaces. This demonstrates that VL fascicle lengthening is greater when the surface stiffness increases, when performing single-leg landing. This is due to the combination of limited knee joint flexion and lower surface absorption ability which resulted in greater mechanical demand mainly withstood by fascicles. GM muscle-tendon interactions remain similar between landing surfaces and types. Together, this suggests that surface damping properties primarily affect the VL muscle-tendon unit with a potentially higher risk of injury as a result of increased surface stiffness when performing single-leg landing tasks.