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Background: Delayed onset muscle soreness (DOMS) refers to micro-injuries in skeletal muscle fibers resulting from excessive mechanical stress during exercise. This leads to inflammation of the muscles, resulting in pain and stiffness. Purpose: This study aims to investigate (1) the differences between eccentric exercise and proprioceptive neuromuscular facilitation (PNF) stretching regarding flexibility levels and their effects on pain reduction in DOMS; (2) the differences in pain reduction between individuals with high versus low flexibility levels; and (3) the interaction between exercise therapy methods (eccentric exercise and PNF) and flexibility levels on pain reduction in DOMS. Methods: A quasi-experimental design was adopted, and a two-way analysis of variance (ANOVA) was used. The study recruited participants via purposive sampling, where diverse features defined the inclusion criterion and provided written consent for all research phases. Sixty male participants were divided into four groups: A1B1, A1B2, A2B1, and A2B2. Data were analyzed using descriptive and inferential statistics (hypothesis testing) through Microsoft Excel, Origin Pro 18, and SPSS 25. DOMS was induced, and treatment sessions were delivered in five sets per session at 24, 48, and 72 hours over a week. Pain intensity was evaluated using the Visual Analog Scale (VAS). Results: 1) The results showed that DOMS pain had reduced more with eccentric exercise than PNF with an F-interaction value of 96.494, the p-value, (0.000) < 0.05 significance level. The mean pain reduction score in eccentric exercise was 6.30, while that recorded for the PN F group was 4.10. 2) There were also significant differences in pain reduction between high and low flexibility levels, as indicated by an F-value (F_inter_B) of 25.608 with a p-value of 0.000 (p < 0.05). The mean pain reduction in individuals with high flexibility was 5.77, compared to 4.63 for those with low flexibility. 3) A significant interaction was found between exercise therapy methods and flexibility levels in reducing muscle soreness, with an interaction F-value (F_inter_AB) of 12.759 and a p-value of 0.001 (p < 0.05). Conclusion: These results demonstrate that eccentric exercise is more effective in reducing DOMS pain than PNF stretching. Additionally, individuals with higher flexibility levels experience more significant pain reduction compared to those with lower flexibility. The results obtained in this study show a therapeutic exercise that trainers and physical therapists can use. [ABSTRACT FROM AUTHOR]

Background/Objectives: There is a subset of patients with pain who become worse after exercise. To explore this, we examined the responses of people with chronic primary pain to a standardized high intensity exercise protocol used to induce delayed onset muscle soreness (DOMS). Methods: Ten participants with a diagnosis of chronic widespread muscle pain (CWMP) were matched by age and reported gender to ten participants without muscle pain (i.e., no pain (NP)). Participants completed a standardized DOMS protocol. Pain intensity in the arm at rest and with movement was assessed using daily electronic diaries. Peak pain, the timing of peak pain, and the time to recovery were compared between groups. Associations of pain variables with the functional connectivity of the sensorimotor (SMN), cerebellum, frontoparietal control (FPN), and default mode network (DMN) both within network nodes and the rest of the brain was assessed. Results: Significant differences in peak pain, the time to peak pain, and the time to recovery were noted between groups for both pain at rest and pain with movement after controlling for catastrophizing and pain resilience. Connectivity across the SMN, FPN, and DMN was associated with all pain-related variables. Significant group differences were identified between groups. Conclusions: A standardized muscle "injury" protocol resulted in more pain, a longer time to peak pain, and a longer time to resolve pain in the patient group compared to the NP group. These differences were associated with differences in connectivity across brain regions related to sensorimotor integration and appraisal. These findings provide preliminary evidence of the dysregulation of responses to muscle (micro)trauma in people with chronic pain. [ABSTRACT FROM AUTHOR]

BACKGROUND: Delayed onset muscle soreness (DOMS) is one of the most prevalent musculoskeletal symptoms in individuals engaged in strenuous exercise programs. OBJECTIVE: This study investigated the effects of wearable low-intensity continuous ultrasound on muscle biomechanical properties during DOMS. METHODS: Twenty volunteers were distributed into a wearable ultrasound stimulation group (WUG) (n = 10) and medical ultrasound stimulation group (MUG) (n = 10). All subjects performed wrist extensor muscle strength exercises to induce DOMS. At the site of pain, ultrasound of frequency 3 MHz was applied for 1 h or 5 min in each subject of the WUG or MUG, respectively. Before and after ultrasound stimulation, muscle biomechanical properties (tone, stiffness, elasticity, stress relaxation time, and creep) and body temperature were measured, and pain was evaluated. RESULTS: A significant decrease was found in the tone, stiffness, stress relaxation time, and creep in both groups after ultrasound stimulation (all p < 0.05). A significant decrease in the pain and increases in temperature were observed in both groups (all p < 0.05). No significant differences were observed between the groups in most evaluations. CONCLUSION: The stiffness and pain caused by DOMS were alleviated using a wearable ultrasound stimulator. Furthermore, the effects of the wearable ultrasound stimulator were like those of a medical ultrasound stimulator. [ABSTRACT FROM AUTHOR]

Muscle damage could affect the next match performance in sports when the time to recover from a previous match is shorter. We examined the interval between matches in nine team sports (e.g., soccer, rugby, field hockey, basketball, volleyball, baseball) and two racket sports (badminton, tennis) in World Cups held in 2022-2023, 2020 Tokyo Olympic Games and Gland Slam in 2023. We then performed narrative review using three electronic databases (PubMed, Scopus, Google Scholar) to get information about muscle damage and recovery in the 11 sports, and discussed whether the intervals in the events would be enough for athletes. We found that the match intervals varied among sports and events ranging from 0 to 17 days. The interval was the shortest for softball (0-2 days) and the longest (5-17 days) for rugby. Regarding muscle damage, changes in muscle function and/or performance measures after a match were not reported for cricket, volleyball and softball, but some information was available for other sports, although the studies did not necessarily use athletes who participated in the major events. It was found that recovery was longer for soccer and rugby than other sports. Importantly, the match-intervals in the events did not appear to accommodate the recovery time required from the previous match in many sports. This could increase a risk of injury and affect players' conditions and health. Changing the match-intervals may be difficult, since it affects the budget of sporting events, but an adequate interval between matches should be considered for each sport from the player's and coach's point of view. [ABSTRACT FROM AUTHOR]

Purpose: To examined the time-course of the early and late phase of the rate of voluntary force development (RVFD) and muscle damage markers after downhill running. Methods: Ten recreational runners performed a 30-min downhill run at 10 km h−1 and −20% (−11.3°) on a motorized treadmill. At baseline and each day up to 4 days RVFD, knee extensors maximum voluntary isometric force (MVIC), serum creatine kinase (CK) concentration, quadriceps swelling, and soreness were assessed. The early (0–50 ms) and late (100–200 ms) phase of the RVFD, as well as the force developed at 50 and 200 ms, were also determined. Results: MVIC showed moderate decrements (p < 0.05) and recovered after 4 days (p > 0.05). Force at 50 ms and the early phase were not impaired (p > 0.05). Conversely, force at 200 ms and the late phase showed moderate decrements (p < 0.05) and recovered after 3 and 4 days, respectively (p > 0.05). CK concentration, quadriceps swelling, and soreness increased (p < 0.05) were overall fully resolved after 4 days (p > 0.05). Conclusion: Downhill running affected the knee extensors RVFD late but not early phase. The RVFD late phase may be used as an additional marker of muscle damage in trail running. [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]

Eccentric muscle contractions can cause structural damage to muscle cells resulting in temporarily decreased muscle force production and soreness. Prior work indicates pasture-raised dairy products from grass-fed cows have greater anti-inflammatory and antioxidant properties compared to grain-fed counterparts. However, limited research has evaluated the utility of whey protein from pasture-raised, grass-fed cows to enhance recovery compared to whey protein from non-grass-fed cows. Therefore, using a randomized, placebo-controlled design, we compared the effect of whey protein from pasture-raised, grass-fed cows (PRWP) to conventional whey protein (CWP) supplementation on indirect markers of muscle damage in response to eccentric exercise-induced muscle damage (EIMD) in resistance-trained individuals. Thirty-nine subjects (PRWP, n = 14; CWP, n = 12) completed an eccentric squat protocol to induce EIMD with measurements performed at 24, 48, and 72 h of recovery. Dependent variables included: delayed onset muscle soreness (DOMS), urinary titin, maximal isometric voluntary contraction (MIVC), potentiated quadriceps twitch force, countermovement jump (CMJ), and barbell back squat velocity (BBSV). Between-condition comparisons did not reveal any significant differences (p ≤ 0.05) in markers of EIMD via DOMS, urinary titin, MIVC, potentiated quadriceps twitch force, CMJ, or BBSV. In conclusion, neither PRWP nor CWP attenuate indirect markers of muscle damage and soreness following eccentric exercise in resistance-trained individuals. [ABSTRACT FROM AUTHOR]

BACKGROUND: Unaccustomed exercise triggers skeletal muscle damage, but produces a specific training effect that reduces muscle re-injury to reduce pain - muscle memory. OBJECTIVE: Based on the etiology of delayed onset muscle soreness, to review the existence and possible mechanism of skeletal muscle memory in delayed onset muscle soreness and to present new insights into the prevention and treatment of delayed onset muscle soreness. METHODS: The first author searched in PubMed, Embase, Web of Science, CNKI and WanFang databases for relevant literature published from January 1990 to December 2022. The keywords were “DOMS, skeletal muscle memory, exercise skeletal muscle adaptation, repeat turn effect, exercise and autophagy, autophagy and inflammation” in English and Chinese, respectively. A total of 102 articles were finally included for review. RESULTS AND CONCLUSION: The etiology of delayed onset muscle soreness is currently believed to be an acute inflammatory response due to metabolic disorders, mechanical injury and oxidative stress, while exercise-induced skeletal muscle memory can reduce delayed onset muscle soreness and exercise reinjury. When the duration, frequency and intensity of centrifugal training are gradually increased, symptoms of the injury can be minimized or even avoided. Therefore, based on the mechanism of exercise-induced skeletal muscle memory, it is the future research direction to find more effective ways to prevent and alleviate exercise-induced muscle injury. This review aims to (1) clarify the existence of exercise-induced skeletal muscle memory; (2) explore the possible mechanisms of exercise-induced skeletal muscle memory and propose the relationship between this memory and skeletal muscle autophagy; and (3) provide new strategies for the prevention and treatment of delayed onset muscle soreness by improving the level of skeletal muscle autophagy. [ABSTRACT FROM AUTHOR]

Exercise-induced muscle damage (EIMD) is a common phenomenon resulting from high-intensity exercise that impairs subsequent performance. Ischaemic post-conditioning (IPOC) is a simple intervention that has been shown to reduce muscle damage after prolonged ischaemia, a condition mechanistically similar to EIMD. The purpose of this study was to determine whether IPOC could alleviate muscle damage after eccentric exercise. Thirty-two young male participants were randomized into either a sham (n = 16) or an IPOC (n = 16) intervention group. Biceps brachii muscle damage was induced by eccentric exercise, with IPOC or sham intervention applied on the dominant arm following exercise (3 cycles of 30 s ischaemia). Visual analogue scale (VAS) pain, arm circumference, muscle thickness, echo-intensity, and microvascular function (using near-infrared spectroscopy) were measured bilaterally at baseline, 24, 48, and 72 hours after eccentric exercise. Biceps curl one repetition maximum (1RM) was also measured. 1RM was higher for the IPOC group at 48 and 72 hours (both p < 0.05). On the dominant arm, VAS pain was lower at 72 hours for the IPOC group (p = 0.039). Muscle thickness was lower at all post-exercise time points for the IPOC group (all p < 0.05). VAS pain, echo-intensity, and arm circumference were elevated on the non-dominant arm in the sham group at 72 hours (all p < 0.05). These parameters all returned to the baseline level for the IPOC group at 72 hours (all p > 0.05IPOC could attenuate the decrease in strength, and alleviate EIMD with both local and remote effects after high-intensity exercise. [ABSTRACT FROM AUTHOR]

Delayed onset muscle soreness (DOMS) of the lower back is considered a surrogate for acute low back pain (aLBP) in experimental studies. Of note, it is often unquestioningly assumed to be muscle pain. To date, there has not been a study analyzing lumbar DOMS in terms of its pain origin, which was the aim of this study. Sixteen healthy individuals (L-DOMS) were enrolled for the present study and matched to participants from a previous study (n = 16, L-PAIN) who had undergone selective electrical stimulation of the thoracolumbar fascia and the multifidus muscle. DOMS was induced in the lower back of the L-DOMS group using eccentric trunk extensions performed until exhaustion. On subsequent days, pain on palpation (100-mm analogue scale), pressure pain threshold (PPT), and the Pain Sensation Scale (SES) were used to examine the sensory characteristics of DOMS. Pain on palpation showed a significant increase 24 and 48 h after eccentric training, whereas PPT was not affected (p > 0.05). Factor analysis of L-DOMS and L-PAIN sensory descriptors (SES) yielded a stable three-factor solution distinguishing superficial thermal ("heat pain ") from superficial mechanical pain ("sharp pain") and "deep pain." "Heat pain " and "deep pain" in L-DOMS were almost identical to sensory descriptors from electrical stimulation of fascial tissue (L-PAIN, all p > 0.679) but significantly different from muscle pain (all p < 0.029). The differences in sensory description patterns as well as in PPT and self-reported DOMS for palpation pain scores suggest that DOMS has a fascial rather than a muscular origin. [ABSTRACT FROM AUTHOR]

Similar impact on proprioception has been observed in participants with lumbar delayed-onset muscle soreness (DOMS) and chronic low back pain (LBP), raising questions about the relevance of lumbar DOMS as a suitable pain model for LBP when assessing back pain-related postural stability changes. Does lumbar DOMS impact postural stability? Twenty healthy adults participated in this experimental study and underwent a posturographic examination before and 24 to 36 h after a protocol designed to induce lumbar DOMS. Posturographic examination was assessed during quiet standing on both feet with eyes opened (EO), with eyes closed (EC), and on one-leg (OL) standing with eyes opened. Postural stability was assessed through center of pressure (COP) parameters (COP area, velocity, root mean square, mean power frequency) which were compared using repeated measure ANOVA. Moreover, pain, soreness and pressure pain threshold (PPT) on specific muscles were assessed. There was a significant main effect of the postural condition on all COP variables investigated. More specifically, each COP variable reached a significantly higher value in the OL stance condition than in both EO and EC bipedal conditions (all with p < 0.001). In addition, the COP velocity and the mean power frequency along the anteroposterior direction both reached a significantly higher value in EC than in EO (p < 0.001). In contrast, there was no significant main effect of the DOMS nor significant DOMS X postural condition interaction on any of the COP variables. There was a significant decrease in the PPT value for both the left and right erector spinae muscles, as well as the left biceps femoris. Lumbar DOMS had no impact on postural stability, which contrasts findings in participants with clinical LBP. Although DOMS induces similar trunk sensorimotor adaptations to clinical LBP, it does not appear to trigger similar postural stability adaptations. • Lumbar delayed onset muscle soreness (DOMS) does not affect postural stability. • Differences between lumbar DOMS and clinical low back pain (LBP). • Lumbar DOMS as a suitable pain model for clinical LBP remains to be studied. [ABSTRACT FROM AUTHOR]

Percussive massage (PM) is an emerging recovery treatment despite the lack of research on its effects post-eccentric exercise (post-EE). This study investigated the effects of PM treatments (immediately, 24, 48, and 72 h post-EE) on the maximal isometric torque (MIT), range of motion (ROM), and an 11-point numerical rating scale (NRS) of soreness of the nondominant arm's biceps brachii from 24 - 72 h post-EE. Seventeen untrained, college-aged subjects performed 60 eccentric elbow flexion actions with their nondominant arms. Nine received 1 minute of PM, versus eight who rested quietly (control [CON]). In order, NRS, ROM, and MIT (relative to body mass) were collected pre-eccentric exercise (pre-EE) and after treatment (AT) at 24, 48, and 72 h post-EE. NRS was also collected before treatment (BT). Electromyographic (EMG) and mechanomyographic (MMG) amplitudes were collected during the MIT and normalized to pre-EE. There were no interactions for MIT, EMG, or MMG, but there were interactions for ROM and NRS. For ROM, the PM group had higher values than the CON 24-72 h by -6-8°, a faster return to pre-EE (PM: 48 h, CON: 72 h), and exceeded their pre-EE at 72 h by -4°. The groups' NRS values did not differ BT 24-72 h; however, the PM group lowered their NRS from BT to AT within every visit by -1 point per visit, which resulted in them having lower values than the CON from 24-72 h by -2-3 points. Additionally, the PM group returned their NRS to pre-EE faster than the CON (PM: BT 72 h, CON: never). In conclusion, PM treatments may improve ROM without affecting isometric strength or muscle activation 24 - 72 h post-EE. Although the PM treatments did not enhance the recovery from delayed onset muscle soreness until 72 h, they consistently provided immediate, temporary relief when used 24 - 72 h post-EE. [ABSTRACT FROM AUTHOR]

This study aims to identify the effects of therapeutic massage on muscle recovery, physiological, psychological and performance in sport. Articles were identified from several databases by searching MEDLINE, Embase, CINAHL, PEDro, Web of Science, Scopus, Google Scholar, and PubMed starting from 2010 to 2023, related through databases according to predefined inclusion criteria that were identified previously. In the review, 31 studies were considered to be eligible for inclusion by recruiting male (n=558) participants, aged between 12 and 60 years, and females (n=226) participants, aged between 12 and 60 years. Compared with the active control, twelve studies found massage to have a significant and measurable benefit, whereas five studies found no obvious advantage. Comparing massage with an inactive control, four studies reported massage to have a significant and considerable effect, whereas three studies did not. For massage compared with other therapies, three studies reported massage to have a measurable and considerable effect, whereas two studies did not. Massage as a stand-alone treatment provided a considerable and substantial benefit in two studies, whereas one study found no significant impact on muscle healing, performance, physiological, and psychological. In conclusion, the current study revealed that massage had a large and substantial advantage when compared with an inactive and active control, but not when compared with other interventions, as examined in this review. There was a shred of conflicting evidence to prove the superior outcomes of massage when administered as a stand-alone treatment and relative to other forms of therapies. However, the efficiency of massage is rarely assessed. [ABSTRACT FROM AUTHOR]

Muscle damage could affect the next match performance in sports when the time to recover from a previous match is shorter. We examined the interval between matches in nine team sports (e.g., soccer, rugby, field hockey, basketball, volleyball, baseball) and two racket sports (badminton, tennis) in World Cups held in 2022-2023, 2020 Tokyo Olympic Games and Gland Slam in 2023. We then performed narrative review using three electronic databases (PubMed, Scopus, Google Scholar) to get information about muscle damage and recovery in the 11 sports, and discussed whether the intervals in the events would be enough for athletes. We found that the match intervals varied among sports and events ranging from 0 to 17 days. The interval was the shortest for softball (0–2 days) and the longest (5–17 days) for rugby. Regarding muscle damage, changes in muscle function and/or performance measures after a match were not reported for cricket, volleyball and softball, but some information was available for other sports, although the studies did not necessarily use athletes who participated in the major events. It was found that recovery was longer for soccer and rugby than other sports. Importantly, the match-intervals in the events did not appear to accommodate the recovery time required from the previous match in many sports. This could increase a risk of injury and affect players’ conditions and health. Changing the match-intervals may be difficult, since it affects the budget of sporting events, but an adequate interval between matches should be considered for each sport from the player’s and coach's point of view.

Carmina Liana Musat,1,&ast; Elena Niculet,1,2,&ast; Mihaela Craescu,1,2,&ast; Luiza Nechita,3 Lina Iancu,4 Aurel Nechita,3 Doina-Carina Voinescu,3 Carmen Bobeica5,&ast; 1Department of Morphological and Functional Sciences, Faculty of Medicine and Pharmacy, “Dun&abreve;rea de Jos” University, Galați, 800008, Romania; 2Multidisciplinary Integrated Center of Dermatological Interface Research MIC-DIR (Centrul Integrat Multidisciplinar de Cercetare de Interfata Dermatologica - CIM-CID), “Dun&abreve;rea de Jos” University, Galați, Romania; 3Clinical Medical Department, Faculty of Medicine and Pharmacy, “Dun&abreve;rea de Jos” University, Galați, 800008, Romania; 4Faculty of Medicine and Pharmacy, “Dun&abreve;rea de Jos” University, Galați, 800008, Romania; 5Medical Department, Faculty of Medicine and Pharmacy, “Dun&abreve;rea de Jos” University, Galați, 800008, Romania&ast;These authors contributed equally to this workCorrespondence: Elena Niculet; Mihaela Craescu, Department of Morphological and Functional Sciences, Faculty of Medicine and Pharmacy, “Dun&abreve;rea de Jos” University, 35 Alexandru Ioan Cuza Street, Galati, 800216, Romania, Tel +40741398895 ; +40751869864, Email helena_badiu@yahoo.com; mihaela.craescu@ugal.roPurpose: The identification of sports and physical exercises with injury risk is necessary to preserve the capacity of athletes and people who perform physical education and also to prevent the installation of functional deficiencies.Methods: We have selected the articles related to the pathogenic mechanisms involved in musculotendinous and fascial injuries produced as a result of physical exercise.Results and Discussions: The lesional pathogenesis is complex and incompletely clarified. Recent theories put in a new light the mechanisms of muscle pain and tendinopathy production. The accumulation of lactate anion, known to be a residue that induces fatigue and muscle pain, has been reconsidered by some authors. It appears that lactate anion is an excellent fuel for the myocardial fiber. Moreover, the accumulation of lactic acid after intense physical exercise could prevent the inexcitability of the sarcolemma induced by the increased concentration of interstitial K+. Most of the time, overuse injuries are not limited to muscles. They can cause myofascial, myotendinous or purely muscular injuries. The muscular fascia is more susceptible to injuries produced under the action of large external forces. Also, fascia is more sensitive to pain compared to muscle when external forces act eccentrically. Overloading the tendon and putting it under tension repeatedly is followed by ruptures of the tendon fibers. The regeneration of the degenerated tendon is defective in the context of the inflammation produced by the injury. Tendon fibers undergo a process of fibrosis, scarring, adhesion and heterogeneous calcification. Oxidative stress is responsible for inflammation, degeneration and apoptosis of tenocytes.Conclusion: The benefits brought by physical education and sports are indisputable, but their practice requires a coordinated program to prevent possible traumatic and overuse injuries.Keywords: sport muscle injury, musculofascial injury, pathogenesis, stress tendinopathy, delayed onset muscle soreness

Exercise-induced muscle damage (EIMD) is a common phenomenon resulting from high intensity exercise that impairs subsequent performance. Ischaemic post-conditioning (IPOC) is a simple intervention that has been shown to reduce muscle damage after prolonged ischaemia, a condition mechanistically similar to EIMD. The purpose of this study was to determine whether IPOC could alleviate muscle damage after eccentric exercise. Thirty-two young male participants were randomized into either a sham ( n = 16) or an IPOC ( n = 16) intervention group. Biceps brachii muscle damage was induced by eccentric exercise, with IPOC or sham intervention applied on the dominant arm following exercise (3 cycles of 30 s ischaemia). Visual analogue scale (VAS) pain, arm circumference, muscle thickness, echo intensity, and microvascular function (using near-infrared spectroscopy) were measured bilaterally at baseline, 24, 48, and 72 hours after eccentric exercise. Biceps curl one repetition maximum (1RM) was also measured. 1RM was higher for the IPOC group at 48 and 72 hours (both p < 0.05). On the dominant arm, VAS pain was lower at 72 hours for the IPOC group ( p = 0.039). Muscle thickness was lower at all post-exercise time points for the IPOC group (all p < 0.05). VAS pain, echo-intensity, and arm circumference were elevated on the non-dominant arm in the sham group at 72 hours (all p < 0.05). These parameters all returned to the baseline level for the IPOC group at 72 hours (all p > 0.05IPOC could attenuate the decrease in strength, and alleviate EIMD with both local and remote effects after high-intensity exercise.

Delayed onset muscle soreness (DOMS) develops after performing unaccustomed eccentric exercises. Animal studies have shown that DOMS is mechanical hyperalgesia through nociceptor sensitization induced by nerve growth factor (NGF) and glial cell line‐derived neurotrophic factor (GDNF) upregulated by cyclooxygenase‐2 (COX‐2). However, no previous study has investigated these in relation to DOMS in humans. This study compared the first and second bouts of one‐leg eccentric cycling (ECC) for changes in NGF, GDNF, and COX‐2 mRNA in the vastus lateralis (VL). Seven healthy adults (18–40 years) performed two bouts of ECC (10 sets of 50 contractions) with 80% maximal voluntary concentric peak torque separated by 2 weeks (ECC1, ECC2). Muscle soreness that was assessed by a visual analog scale and maximal voluntary isometric contraction (MVC) torque of the knee extensors were measured before, immediately after (MVC only), 24 and 48 h post‐exercise. Muscle biopsy was taken from the VL before the first bout from nonexercised leg (control) and 24 h after each bout from the exercised leg, and analyzed for NGF, GDNF, and COX‐2 mRNA. Peak DOMS was more than two times greater and MVC torque at 48 h post‐exercise was approximately 20% smaller after ECC1 than ECC2 (p < 0.05), suggesting the repeated bout effect. NGF mRNA level was higher (p < 0.05) post‐ECC1 (0.79 ± 0.68 arbitrary unit) than control (0.06 ± 0.07) and post‐ECC2 (0.08 ± 0.10). GDNF and COX‐2 mRNA did not show significant differences between control, post‐ECC1, and post‐ECC2. These results suggest that an increase in NGF is associated with the development of DOMS in humans. [ABSTRACT FROM AUTHOR]

This systematic review and meta-analysis compared muscle damage markers and physical performance measures between 2 bouts of multiarticular exercises and determined whether intensity and volume of muscle-damaging exercises affected the outcomes. The eligibility criteria consisted of (a) healthy male and female adults; (b) multiarticular exercises to cause muscle damage across 2 bouts; (c) outcome measures were compared at 24-48 hours after the first and second bouts of muscle-damaging exercise; (d) at least one of the following outcome measures: creatine kinase (CK), delayed onset of muscle soreness (DOMS), muscle strength, and running economy. Study appraisal was conducted using the Kmet tool, whereas forest plots were derived to calculate standardized mean differences (SMDs) and statistical significance and alpha set a 0.05. After screening, 20 studies were included. The levels of DOMSand CK were significantly greater during the first bout when compared with the second bout at T24 and T48 (p<0.001;SMD = 0.51-1.23). Muscular strength and vertical jump performance were significantly lower during the first bout compared with the second bout at T24 and T48 (p ≤ 0.05; SMD = -0.27 to -0.40), whereas oxygen consumption and rating of perceived exertion were significantly greater during the first bout at T24 and T48 (p<0.05; SMD=0.28-0.65) during running economy protocols. The meta-analyses were unaffected by changes in intensity and volume of muscle-damaging exercises between bouts. Multiarticular exercises exhibited a repeated bout effect, suggesting that a single bout of commonly performed exercises involving eccentric contractions may provide protection against exercise-induced muscle damage for subsequent bouts. [ABSTRACT FROM AUTHOR]

The present study compared the ipsilateral repeated bout effect (IL‐RBE) and contralateral repeated bout effect (CL‐RBE) of the elbow flexors (EF) and knee flexors (KF) for the same interval between bouts to shed light on their mechanisms. Fifty‐two healthy sedentary young (20–28 years) men were randomly assigned to the IL‐EF, IL‐KF, CL‐EF, and CL‐KF groups (n = 13/group). Thirty maximal eccentric contractions of the EF were performed in IL‐EF and CL‐EF, and 60 maximal eccentric contractions of the KF were performed in IL‐KF and CL‐KF, with a 2‐week interval between bouts. Changes in muscle damage markers such as maximal voluntary contraction (MVC) torque, muscle soreness, and plasma creatine kinase activity, and proprioception measures before to 5 days post‐exercise were compared between groups. Changes in all variables were greater (p < 0.05) after the first than second bout for all groups, and the changes were greater (p < 0.05) for the EF than KF. The changes in all variables after the second bout were greater (p < 0.05) for the CL than IL condition for both EF and KF. The magnitude of the average protective effect was similar between CL‐EF (33%) and CL‐KF (32%), but slightly greater (p < 0.05) for IL‐EF (67%) than IL‐KF (61%). These demonstrate that the magnitude of CL‐RBE relative to IL‐RBE was similar between the EF and KF (approximately 50%), regardless of the greater muscle damage for the EF than KF. It appears that the CL‐RBE is more associated with neural adaptations at cerebrum, cerebellum, interhemispheric inhibition, and coricospinal tract, but the IL‐RBE is induced by additional adaptations at muscles. [ABSTRACT FROM AUTHOR]

Tribulus terrestris L. contains compounds with antioxidant and anti-inflammatory properties, but its effects on exercise-induced oxidative stress and inflammatory responses are unclear. The aim of this study was to examine whether Tribulus terrestris L. supplementation can attenuate oxidative stress and inflammatory responses to acute aerobic exercise and improve DOMS. In a randomized, double-blind, crossover design study, thirteen healthy men received either a daily supplement of Tribulus terrestris L. or a placebo for 4 weeks (2-week wash-out period between trials). Before and after the supplementation periods, participants performed an exercise test to exhaustion (75% VO2max). DOMS, thigh girth, and knee joint range of motion (KJRM) were assessed before and after the exercise (2, 24, and 48 h). Blood samples were analyzed for reduced (GSH) and oxidized (GSSG) glutathione, GSH/GSSG ratio, protein carbonyls, total antioxidant capacity, creatine kinase activity, white blood cell count, and TBARS. Acute exercise to exhaustion induced inflammatory responses and changed the blood redox status in both Tribulus and Placebo groups (p < 0.050). Tribulus terrestris L. improved GSH fall (p = 0.005), GSSG rise (p = 0.001) and maintained a higher level of GSH/GSSG ratio at the 2 h point (p = 0.034). TBARS were lowered, protein carbonyls, creatine kinase activity, and white blood cell count elevation diminished significantly (p < 0.050). Tribulus terrestris L. administration did not affect DOMS, thigh girth, or KJRM (p > 0.050). 4-weeks of Tribulus terrestris L. supplementation effectively attenuates oxidative stress responses but cannot improve DOMS. [ABSTRACT FROM AUTHOR]

ABSTRACTBackground Cannabinoid-containing products are marketed to athletes as promoting recovery, in spite of a lack of data on their safety and effects. This randomized, double-blind, placebo-controlled, repeated-dose pilot study tested the safety, tolerability, and preliminary effects on recovery of a formulation containing cannabidiol (CBD; 35 mg), cannabigerol (CBG; 50 mg), beta caryophyllene (BCP; 25 mg), branched-chain amino acids (BCAAs; 3.8 g), and magnesium citrate (420 mg).Methods Exercise-trained individuals (N = 40) underwent an experimental induction of delayed onset muscle soreness (DOMS) and completed follow-up visits 24-, 48-, and 72-hours post-DOMS. Participants were randomized to active or placebo formulation, and consumed the formulation twice per day for 3.5 days.Results There was one adverse event (AE) in the active group (diarrhea) and two AEs in placebo (dry mouth; eye rash/swollen eye). There was 100% self-reported compliance with formulation consumption across the two groups. For the primary outcome of interest, the estimate of effect for ratings of average soreness/discomfort 72 hours post-DOMS between active and placebo groups was −1.33 (85% confidence interval = -2.55, −0.10), suggesting moderate evidence of a treatment difference. The estimate of effect for the outcome of ratings of interference of soreness, discomfort, or stiffness on daily activities at work or home 48 hours post-DOMS was −1.82 (95% confidence interval = -3.64, −0.01), indicating a treatment difference of potential clinical importance. There was no significant effect between active and placebo groups on objective measures of recovery, sleep quality, or mood disturbance.Conclusions The tested formulation reduced interference of DOMS on daily activities, demonstrating its improvement on a functional aspect of recovery.

Purpose: Eccentric muscle actions generate high levels of force at a low metabolic cost, making them a suitable training modality to combat age-related neuromuscular decline. The temporary muscle soreness associated with high intensity eccentric contractions may explain their limited use in clinical exercise prescription, however any discomfort is often alleviated after the initial bout (repeated bout effect). Therefore, the aims of the present study were to examine the acute and repeated bout effects of eccentric contractions on neuromuscular factors associated with the risk of falling in older adults. Methods: Balance, functional ability [timed up-and-go and sit-to-stand], and lower-limb maximal and explosive strength were measured in 13 participants (67.6 ± 4.9 year) pre- and post-eccentric exercise (0, 24, 48, and 72 hr) in Bout 1 and 14 days later in Bout 2. The eccentric exercise intervention was performed on an isokinetic unilateral stepper ergometer at 50% of maximal eccentric strength at 18 step‧min−1 per limb for 7 min (126 steps per limb). Two-way repeated measures ANOVAs were conducted to identify any significant effects (P ≤ 0.05). Results: Eccentric strength significantly decreased (− 13%) in Bout 1 at 24 hr post-exercise; no significant reduction was observed at any other time-point after Bout 1. No significant reductions occurred in static balance or functional ability at any time-point in either bout. Conclusion: Submaximal multi-joint eccentric exercise results in minimal disruption to neuromuscular function associated with falls in older adults after the initial bout. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the changes in skeletal muscle (SM) α-actin, myoglobin (Mb) and hydroxyproline (HP) in plasma and other indirect markers of muscle damage after repeated bouts of eccentric cycling. Methods: Ten healthy men (23.3 ± 2.8 years) performed two 30-min eccentric cycling bouts at 100% of maximal concentric power output (230.7 ± 36.9 W) separated by 2 weeks (ECC1 and ECC2). Maximal voluntary isometric contraction (MVIC) peak force of the knee extensor muscles, muscle soreness (SOR), pain pressure threshold (PPT) and plasma levels of SM α-actin, Mb, and HP were measured before, 0.5, 3, 24–168 h after each cycling bout. Results: MVIC peak force decreased on average 10.7 ± 13.1% more after ECC1 than ECC2. SOR was 80% greater and PPT was 12–14% lower after ECC1 than ECC2. Plasma SM α-actin levels increased at 0.5, 3, and 24–72 h after ECC1 (26.1–47.9%), and SM α-actin levels at 24 h after ECC1 were associated with muscle strength loss (r = −0.56, P =.04) and SOR (r = 0.88, P =.001). Mb levels increased at 0.5, 3, and 24 h after ECC1 (200–502%). However, Mb levels at 24 h after ECC1were not associated with muscle strength loss and SOR. HP levels remained unchanged after ECC1. ECC2 did not increase SM α-actin, Mb and HP levels. Conclusion: Our results indicate that α-actin could be used as a potential marker for the early identification of SM damage due to its early appearance in plasma and its association with other indirect markers of muscle damage. [ABSTRACT FROM AUTHOR]

Hamstring strain is likely to occur during the late swing phase or the first half of the stance phase in sprinting. During the late swing phase, the hamstrings and gluteus maximus (Gmax) contract eccentrically to decelerate the lower limb. We hypothesized that, when the Gmax becomes dysfunctional because of delayed onset muscle soreness (DOMS), the hamstring workload is increased (i.e., there is synergetic dominance), which could lead to an increased risk of strain. A total of healthy 15 male undergraduate or graduate students (age 23.1 ± 1.28 years) were recruited to perform exercises and maximal sprints. On day 1, before subjects performing DOMS-causing exercises, and on day 3, while subjects were experiencing DOMS in the Gmax, lower-limb biomechanical and muscle activity data were recorded using a motion analysis system and electromyography (EMG), respectively. Data were analyzed and compared between day 1 and day 3. Hip flexion angle on day 3 was significantly lower than that on day 1, but the opposite was true for the knee flexion angle (P < 0.05). Vastus medialis (VM), biceps femoris (BF), and Gmax muscle activities on day 3 were significantly higher than those on day 1 (P < 0.05). Peak propulsive forces on day 3 were significantly higher than those on day 1 (P < 0.05). Kinematic changes such as decreased hip flexion angle and EMG changes such as increased BF EMG activity on day 3 to compensate for the loss of function of the Gmax may potentially increase the risk of hamstring strain. [ABSTRACT FROM AUTHOR]

Neuromuscular electrical stimulation (NMES) offers a potential adjuvant to traditional voice therapy for individuals with dysphonia. The type of vocal task to implement in conjunction with electrical stimulation to achieve maximal therapeutic benefit is unknown. The purpose of this study was to elucidate the impact of tasks on voice outcomes. Nineteen vocally-healthy adult females, between 23 and 27 years of age (Ave: 23.8, SD: 1.13), participated in the study. 15 participants completed all three 30-minute sessions, and four completed at least one session. NMES was paired with three different voice conditions: high-pitched hum, low-pitched hum, and comfortable-pitched hum. Acoustic (average fundamental frequency and loudness; perturbation (jitter, shimmer, noise to harmonic ratio); Cepstral Spectral Index of Dysphonia; pitch range), perceived phonatory effort, and discomfort (delayed onset muscle soreness) measures were compared across conditions. Eight participants experienced discomfort following NMES. Three participants withdrew from the study due to discomfort, and one withdrew due to an unrelated oral surgery. NMES paired with high-pitch humming resulted in increased average fundamental frequency during sustained phonation and reading tasks, and increased Cepstral Spectral Index of Dysphonia during sustained phonation. Low-pitch humming resulted in a decreased noise to harmonic ratio. No statistically significant changes in perceived phonatory effort were noted. Almost half of the participants reported temporary discomfort. Task-specific differences in some outcomes were noted indicating that the nature of voice task performed with NMES must be considered when examining the impact of NMES on voice. Vocal tasks can impact discomfort and acoustic vocal outcomes of NMES. [ABSTRACT FROM AUTHOR]

Introduction: The current research aimed to measure the effects of one-month omega-3 supplement consumption on the most important symptoms of Delayed Onset Muscle Soreness (DOMS) in inactive healthy men. Methods: The current research was a quasi-experimental and applied one in terms of purpose. The statistical population included inactive healthy men from Bukan City. Among them, 22 people were selected as a statistical sample and they were randomly assigned into two equal groups. Participants received a daily dose of 1000 mg omega-3 capsule or a 2% dextrose placebo for one month. After determining 1RM, participants performed the leg press in four sets of 20 repetitions using a leg press machine with a weight of 80% of 1RM. Each contraction lasted 4 seconds. Two ccs of venous blood were drawn by a specialist before the start of the study, 24, 48, and 72 hours after DOMS and measurements were made. For statistical analysis, independent t, repeated measures ANOVA, and Bonferroni's post hoc tests were used. A significance level of 0.05 was considered. Results: Between-group comparison of PGE2, cortisol, pain perception and knee range of motion in all stages of the study in both control and supplement groups had significant differences (P<0.001). The results of the within-group test showed that the average PGE2, cortisol, and pain perception in the supplement group had a significant decrease in all post-intervention stages, while in the control group, there was a significant increase in all stages (P<0.05). Conclusion: Taking omega-3 supplements can reduce the appearance, functional and biochemical symptoms of DOMS in the period after the completion of eccentric and concentric exercises; which can be due to the strong anti-inflammatory properties of omega-3 and the better response of the research participants to omega-3 consumption and better digestive absorption of this supplement. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of a far-infrared radiation (FIR) lamp therapy on changes in muscle damage and proprioception markers after maximal eccentric exercise of the elbow flexors (EF: Study 1) and the knee flexors (KF: Study 2) in comparison to a sham treatment condition. In each study, 24 healthy sedentary women were assigned to a FIR or a sham treatment group (n = 12/group). They performed 72 maximal EF eccentric contractions (Study 1) or 100 maximal KF eccentric contractions (Study 2) with their non-dominant limbs. They received a 30-min FIR (wavelength: 8–14 µm) or sham treatment at 1, 25, 49, 73 and 97 h post-exercise to the exercised muscles. Maximum voluntary isometric contraction (MVC) torque, muscle soreness, plasma creatine kinase activity, and proprioception assessed by position sense, joint reaction angle, and force match were measured before, and 0.5, 24, 48, 72, 96 and 120 h post-exercise. The outcome measures showed significant changes (P < 0.05) at 0.5-hour post-exercise (before treatment) similarly (P > 0.05) between the conditions in both studies. However, changes in all measures at 24–120 h post-exercise were smaller (P < 0.05) for the FIR than sham condition in both studies. For example, MVC torque returned to the baseline by 72 h post-exercise for the FIR condition in both studies, but was still 19 ± 6% (Study 1) or 17 ± 12% (Study 2) lower than the baseline at 120 h post-exercise for the sham condition. These results suggested that the FIR lamp therapy was effective for accelerating recovery from muscle damage. FIR lamp therapy was effective for recovering muscle strength and proprioception 1–3 days faster to the baseline. FIR lamp therapy was effective for attenuating muscle soreness by 55–60%, and reducing peak plasma CK activity by 45–89%. The effects of the FIR lamp therapy appear to be greater than other therapeutic interventions for eccentric exercise-induced muscle damage that have been investigated previously. [ABSTRACT FROM AUTHOR]

Background: Resistance exercise is recommended for maintaining muscle mass and strength in older adults. However, little is known about exercise-induced muscle damage and recovery from resistance exercise in older adults. This may have implications for exercise prescription. This scoping review aimed to identify and provide a broad overview of the available literature, examine how this research has been conducted, and identify current knowledge gaps relating to exercise-induced muscle damage and recovery from resistance exercise in older adults. Methods: Studies were included if they included older adults aged 65 years and over, and reported any markers of exercise-induced muscle damage after performing a bout of resistance exercise. The following electronic databases were searched using a combination of MeSH terms and free text: MEDLINE, Scopus, Embase, SPORTDiscus and Web of Science. Additionally, reference lists of identified articles were screened for eligible studies. Data were extracted from eligible studies using a standardised form. Studies were collated and are reported by emergent theme or outcomes. Results: A total of 10,976 possible articles were identified and 27 original research articles were included. Findings are reported by theme; sex differences in recovery from resistance exercise, symptoms of exercise-induced muscle damage, and biological markers of muscle damage. Conclusions: Despite the volume of available data, there is considerable variability in study protocols and inconsistency in findings reported. Across all measures of exercise-induced muscle damage, data in women are lacking when compared to males, and rectifying this discrepancy should be a focus of future studies. Current available data make it challenging to provide clear recommendations to those prescribing resistance exercise for older people. [ABSTRACT FROM AUTHOR]

Eurycoma longifolia Jack (ELJ) is a herbal plant that has androgenic and antioxidant effects. We investigated the short-term effect of ELJ supplementation on muscle damage induced by eccentric exercise. Eighteen young (19-25 years), well-trained rugby 7s players were assigned to an ELJ or a placebo (PLA) group (n = 9/group). Each participant took four 100-mg capsules a day for seven days prior to performing a leg press eccentric exercise to failure in a double-blind fashion. Peak force, peak power and jump height in countermovement jump (CMJ), drop jump reactive strength index (RSI), muscle soreness assessed by a 100-mm visual analogue scale, plasma creatine kinase (CK) activity, and salivary hormones were measured at 24 h before and 0.5, 24, 48, 72, and 96 h after the exercise. Changes in the variables over time were compared between the groups by two-factor mixed-design ANOVA. The number of eccentric contractions performed was similar (P = 0.984) between the ELJ (21 ± 5) and PLA groups (21 ± 5). Salivary testosterone and cortisol concentrations did not change (P > 0.05) after the supplementation for both groups. CMJ peak power (-9.4 ± 5.6%) and height (-10.6 ± 4.9%), and RSI (-15.2 ± 16.2%) decreased at 24 h after exercise (P < 0.05), and muscle soreness (peak: 89 ±10 mm) and plasma CK activity (peak: 739 ± 420 IU/L) increased after exercise (P < 0.05) without significant differences between groups. These results showed that 7-day ELJ supplementation prior to the leg press eccentric exercise had no significant effects on hormones, performance and muscle damage markers for the athletes. [ABSTRACT FROM AUTHOR]

Unaccustomed eccentric exercise results in muscle damage limiting physical performance for several days. This study investigated if Greenshell™ mussel (GSM) powder consumption expedited muscle recovery from eccentric exercise-induced muscle damage (EIMD). Methods: Twenty untrained adult men were recruited into a double-blind, placebo-controlled, cross-over study and were randomly assigned to receive the GSM powder or placebo treatment first. Participants consumed their allocated intervention for four weeks then completed a bench-stepping exercise that induced muscle damage to the eccentrically exercised leg. Muscle function, soreness and biomarkers of muscle damage, oxidative stress and inflammation were measured before exercise, immediately after exercise and 24, 48 and 72 h post exercise. GSM powder promoted muscle function recovery, significantly improving (p < 0.05) isometric and concentric peak torque at 48 h and 72 h post exercise, respectively. Participants on the GSM treatment had faster dissipation of soreness, with significant treatment × time interactions for affective (p = 0.007) and Visual Analogue Scale-assessed pain (p = 0.018). At 72 h, plasma creatine kinase concentrations in the GSM group were lower (p < 0.05) compared with the placebo group. This study provides evidence for GSM powder being effective in supporting muscle recovery from EIMD. [ABSTRACT FROM AUTHOR]

Context: Several interventions are available to reduce the intensity and duration of the unwanted effects (eg, muscle soreness) associated with physical activity, such as massage, compression garments, and sequential pulse compression (SPC). Such interventions aim to increase blood flow to alleviate symptoms. However, there is a lack of evidence to support the use of SPC to alter total hemoglobin concentration (THb) in active individuals. Objective: To examine the acute effects of a single session of SPC on hemoglobin concentration compared with a control condition. Design: Single cohort, crossover design. Participants: Thirty-four physically active and healthy participants (females = 12 and males = 22) completed the study. Interventions: The authors randomly assigned participants to first receive the experimental (SPC) or control condition. Measures were recorded precondition and postcondition. Participants returned to the laboratory to complete the second condition ≥24 hours after the first condition. Main Outcome Measures: Relative changes in THb, deoxygenated hemoglobin, and oxygenated hemoglobin measures were recorded using near-infrared spectroscopy placed on the muscle belly of the medial gastrocnemius of the dominant limb. Results: SPC significantly increased THb (P < .001, d = 0.505) and oxygenated hemoglobin (P < .001, d = 0.745) change scores compared with the control condition. No statistical difference in deoxygenated hemoglobin change scores was found between the SPC and control conditions, but a medium effect size suggests potential biological significance (P = .06, d = 0.339). Conclusions: Overall, SPC increases THb to the lower-extremity and may be a viable option in the management of muscle soreness related to physical activity. [ABSTRACT FROM AUTHOR]

Eurycoma longifolia Jack (ELJ) is a herbal plant that has androgenic and antioxidant effects. We investigated the short-term effect of ELJ supplementation on muscle damage induced by eccentric exercise. Eighteen young (19–25 years), well-trained rugby 7s players were assigned to an ELJ or a placebo (PLA) group (n = 9/group). Each participant took four 100-mg capsules a day for seven days prior to performing a leg press eccentric exercise to failure in a double-blind fashion. Peak force, peak power and jump height in countermovement jump (CMJ), drop jump reactive strength index (RSI), muscle soreness assessed by a 100-mm visual analogue scale, plasma creatine kinase (CK) activity, and salivary hormones were measured at 24 h before and 0.5, 24, 48, 72, and 96 h after the exercise. Changes in the variables over time were compared between the groups by two-factor mixed-design ANOVA. The number of eccentric contractions performed was similar (P = 0.984) between the ELJ (21±5) and PLA groups (21±5). Salivary testosterone and cortisol concentrations did not change (P > 0.05) after the supplementation for both groups. CMJ peak power (-9.4 ±5.6%) and height (-10.6±4.9%), and RSI (-15.2±16.2%) decreased at 24 h after exercise (P < 0.05), and muscle soreness (peak: 89 ±10 mm) and plasma CK activity (peak: 739±420 IU/L) increased after exercise (P < 0.05) without significant differences between groups. These results showed that 7-day ELJ supplementation prior to the leg press eccentric exercise had no significant effects on hormones, performance and muscle damage markers for the athletes

The Nordic hamstring exercise (NHE) reduces hamstring injury incidence. Compliance to large exercise volumes of the NHE is poor, with exercise related soreness often seen as a contributing factor. We investigated the dose–response of NHE exposure with delayed onset muscle soreness (DOMS) and non‐DOMS pain. Forty males were randomized to a 6‐week intervention of four different NHE dosages: Group 1: very low volume; Group 2: low volume; Group 3: initial high to low volume; Group 4: low to high volume. Group 4 experienced more DOMS (p < 0.05) and non‐DOMS pain (p = 0.030) than other groups. High volumes of NHE increase DOMS and non‐DOMS pain while lower volume protocols have lesser DOMS and non‐DOMS pain responses. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of a 3‐week immobilization (IM) on muscle damage induced by maximal eccentric exercise (MaxEC) to test the hypothesis that the IM would make muscles prone to muscle damage. Young healthy sedentary men were pseudo‐randomly assigned to IM or control group (n = 12/group). Non‐dominant arms of the IM group participants were immobilized at 90° elbow flexion by a cast for 21 days. All participants performed MaxEC consisting of five sets of six elbow flexor contractions by lowering a dumbbell set at 100% of pre‐exercise maximal voluntary isometric contraction (MVC) strength of the non‐dominant arm. This was performed at 2 days after the cast removal for the IM group. MVC torque, range of motion (ROM), muscle thickness (MT), muscle hardness, position sense (PS), and joint reaction angle (JRA) of the elbow flexors were measured at baseline, post‐immobilization, and before, immediately after, and one to 5 days after MaxEC. The IM decreased MVC torque (−17 ± 2%), ROM (−2 ± 1%), MT (−7 ± 3%), and JRA (−12 ± 6%), and increased in muscle hardness (20 ± 6%) and PS (11 ± 2%) (p < 0.05). Changes in MVC (e.g., 2 days: −40 ± 5 vs. −30 ± 9%), ROM (2 days: −11 ± 2 vs. −9 ± 3%), muscle soreness (peak: 63 ± 22 vs. 48 ± 14 mm), plasma CK activity (peak: 7820 ± 4011 vs. 4980 ± 1363 IU/L), PS (maximal change: −23 ± 2 vs. −18 ± 3%), and JRA (maximal change: −37 ± 4 vs. −26 ± 3%) after MaxEC were greater (p < 0.05) for the IM than control group. These results supported the hypothesis and showed that the IM made the muscles more vulnerable to muscle damage induced by eccentric exercise. [ABSTRACT FROM AUTHOR]

Existing equipment for quantitative sensory testing is generally expensive and not easily applicable in a clinical setting thus simple bed-side devices are warranted. Pressure hyperalgesia is a common finding in patients with musculoskeletal pain and an experimental model is delayed-onset muscle soreness (DOMS). DOMS is characterised by muscle hyperalgesia and some studies report facilitation of temporal summation of pain. This study aimed to detect DOMS induced muscle hyperalgesia and temporal summation of pain using a newly developed bed-side quantitative sensory testing device to deliver standardised pressure. Twenty-two healthy participants participated in two sessions with the second session approximately 48 h after baseline. Pressure pain intensities were assessed from the gastrocnemius muscle with four probes calibrated to apply 2, 4, 6 and 8 kg, respectively. Temporal summation of pain (10 stimuli delivered at 0.5 Hz using the 6 kg probe) intensities were assessed from the same location. DOMS was evoked in the gastrocnemius muscle by an eccentric exercise. Sleepiness and physical activity were measured with the Epworth Sleepiness Scale and the Global Physical Activity Questionnaire to investigate if they were associated with the quantitative sensory testing measures. Pressure pain intensity was significantly increased 48 h after induction of DOMS when compared to baseline for all four probes (p<0.05). Temporal summation of pain was not statistically significant affected by DOMS and sleep quality and physical activity did not associate with any of the measures. This study introduces a simple, bed-side assessment tool for the assessment of pressure pain intensity and hence hyperalgesia and temporal summation of pain. [ABSTRACT FROM AUTHOR]

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

Amyotrophic lateral sclerosis (ALS) is a fatal, multisystem neurodegenerative disease that causes the death of motoneurons (MNs) progressively and eventually leads to paralysis. In contrast, delayed onset muscle soreness (DOMS) is defined as delayed onset soreness, muscle stiffness, loss of force-generating capacity, reduced joint range of motion, and decreased proprioceptive function. Sensory deficits and impaired proprioception are common symptoms of both ALS and DOMS, as impairment at the proprioceptive sensory terminals in the muscle spindle is theorized to occur in both. The important clinical distinction is that extraocular muscles (EOM) are relatively spared in ALS, in contrast to limb skeletal muscles; however, the blink reflex goes through a gradual impairment in a later stage of disease progression. Noteworthy is, that, the stretch of EOM induces the blink reflex. The current authors suggest that the impairment of proprioceptive sensory nerve terminals in the EOM muscle spindles are partially responsible for lower blink reflex, beyond central origin, and implies the critical role of Piezo2 ion channels and Wnt-PIP2 signaling in this pathomechanism. The proposed microinjury of Piezo2 on muscle spindle proprioceptive terminals could provide an explanation for the painless dying-back noncontact injury mechanism theory of ALS.

Background: Delayed onset muscle soreness is a type of muscular pain which happen when unsusal movements, including violent as well as unexpected physical actions of great intensity, are achieved. In this study, we investigate the impact of continuous airflow cryotherapy on serum Creatine Kinase level, pain intensity, and elbow flexion and extension range of motion (ROM) in induced muscle soreness in healthy subjects. Methods: Thirty healthy untrained male volunteers were recruited randomly to the study among the surrounding population. The participants were randomized into two groups of equal number, fifteen in each group. Group A received the airflow cryotherapy treatment on the nondominant arm beside rest and home instructions, while group B received rest and home instructions. The procedure includes 4 phases, Baseline measurements (pre-induction) (serum creatine kinase for soreness, visual analogue scale (VAS) for pain intensity measurement, and goniometer for elbow joint ROM) were taken. Results: there was a significant enhancement in serum CK level, pain intensity, as well as elbow ROM elbow (flexion/extension) of the study group in comparison with the control group at post I in addition to post II. Conclusion: continuous airflow Cryotherapy is used to improve function and help patients get back to their pre-injury level of function as soon as possible. [ABSTRACT FROM AUTHOR]

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Background and Objectives Supplementation with amino acids for muscle recovery can be effective on oxidative stress and muscle damage. This study aims to compare the effects of pea protein and whey protein supplements on muscle damage, delayed onset muscle soreness (DOMS), and functional performance after high-intensity functional training (HIFT) bout in untrained overweight young men. Subjects and Methods In this randomized, double-blind, placebo-controlled clinical trial, 30 untrained overweight young men were selected by a purposive sampling method and divided randomly into three different groups of pea protein (n=10), Whey Protein (n=10), and placebo (n=10). Variables related to muscle damage and DOMS were measured 24 hours after HIFT. Repeated measures ANOVA and Bonferroni post hoc test were used to compare the differences between groups. Results There was a significant difference between the two evaluation stages. There was a significant difference between the Whey protein and pea protein groups compared to the placebo group (P<0.05), but no significant difference was found between the Whey protein and pea protein groups (P<0.05). Conclusion The use of Whey protein, compared to pea protein, can reduce muscle damage and DOMS following HIFT. [ABSTRACT FROM AUTHOR]

Background: Delayed onset muscle soreness (DOMS) is a well-established phenomenon characterized by ultrastructural muscle damage that typically develops following unfamiliar or high-intensity exercise. DOMS manifests with a constellation of symptoms, including muscle tenderness, stiffness, edema, mechanical hyperalgesia, and a reduced range of joint motion. In recent years, the application of blood flow restriction (BFR) has garnered attention for its potential impact on DOMS., Objective: This study aimed to investigate the effects of different BFR intensities on biomechanical alterations induced by DOMS in healthy individuals., Design and Methods: Thirty participants were split into two groups receiving either 80% or 20% BFR applied during low-intensity resistance exercise following DOMS induction. Pain perception, pressure pain threshold, muscle biometric characteristics, and strength were assessed before DOMS, after DOMS, and following BFR application at 24, 48, and 72 h., Results: The 80% BFR group experienced faster reductions in pain perception compared to the 20% BFR group. Muscle strength recovery was also statistically faster in the 80% BFR group. No significant differences were observed between groups in muscle stiffness, flexibility, or other mechanical properties., Conclusions: These findings suggest that BFR, particularly at higher intensities, may alleviate DOMS symptoms and accelerate muscle strength recovery. However, the lack of a control group and limitations in muscle property assessment warrant further research to definitively determine BFR's efficacy in managing DOMS., (© 2024 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

This study investigated the effect of five consecutive days of cold-water immersion (CWI) on recovery from exercise-induced muscle damage (EIMD) in the hamstrings following maximal eccentric contraction (EC) exercise. Eighteen healthy adult women were randomly assigned to a CWI group and a control group (CG) (n = 9/group). Participants performed 10 sets of 10 repetitions of isokinetic EC at 30°/second and underwent maximum voluntary isometric contraction (MVC), delayed onset muscle soreness (DOMS) assessment, straight leg raise (SLR) test, and plasma myoglobin (Mb) measurement. The CWI group received one 14-min session of CWI treatment (14°C) at 1, 25, 49, 73, and 97 h after the EC test, whereas the CG rested in a seated position at the same five time points without receiving treatment. (1) All the dependent variables in the CWI group and CG exhibited significant changes after the EC test (p < 0.05). (2) The recovery effect in the CWI group was significantly greater than in the CG in terms of the MVC, DOMS, SLR, and plasma Mb concentration results. MVC increased by 89.3 ± 2.0% on the fourth day (p < 0.013), DOMS decreased by 15.4 ± 1.5 mm on the second day (p < 0.000), SLR increased by 86.3 ± 1.1% on the second day (p < 0.014), and plasma Mb decreased by 436.3 ± 60.8% on the third day (p < 0.014). The study indicates that five consecutive days of CWI at 14°C significantly enhance recovery from exercise-induced muscle damage in the hamstrings., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Background • Cupping therapy originated in Eastern Medicine, became renowned in complementary medicine and is utilized as a therapeutic treatment in contemporary medicine for musculoskeletal issues. As with any modality, there is a question of efficacy. Objective • This study investigated the effect of cupping therapy on muscle stiffness (MS), active dorsiflexion (DF) and perceived pain of the medial gastrocnemius muscle following a cupping therapy treatment. Methods • Single cohort design included 20 physically active, healthy participants (10 women, 10 men; age: 22.9 years ± 3.35 years) completed an exercise protocol to induce delayed onset muscle soreness in both lower legs. Intervention • A 5-minute dry cupping treatment was performed on the dominant leg medial gastrocnemius and 5 minutes of rest for the non-dominant control leg. Primary Outcome Measures • Muscle stiffness, active dorsiflexion and perceived pain were measured at baseline, pre-treatment, post-treatment and 5 minutes posttreatment in the medial gastrocnemius muscle. A repeated measures ANOVA was used to analyze the main effect and interaction for condition and time. Results • Active DF was significantly different from baseline to pre-treatment, post-treatment and 5 minutes post-treatment (P < .001, P < .001, P = .01, respectively). Pre-treatment to 5 minutes post-treatment, active DF was also significantly different (P = .05). Active DF was significantly improved post-treatment and 5 minutes post-treatment. Baseline pain was significantly different from pre-treatment, post-treatment and 5 minutes posttreatment measurements (P < .001, P < .001, P < .001, respectively). Pre-treatment pain was significantly different from post-treatment and 5 minutes post-treatment pain (P = .009, P < .001, respectively). Post-treatment pain was also significantly different from 5 minutes post-treatment pain (P = .007). MS was not significant at any of the time points (P = .398) or between conditions (P = .140). Conclusion • A single cupping treatment significantly improved active DF and decreased pain was observed in the treatment group. No significant difference in MS was observed following the treatment. [ABSTRACT FROM AUTHOR]

Piezo2 transmembrane excitatory mechanosensitive ion channels were identified as the principal mechanotransduction channels for proprioception. Recently, it was postulated that Piezo2 channels could be acutely microdamaged on an autologous basis at proprioceptive Type Ia terminals in a cognitive demand-induced acute stress response time window when unaccustomed or strenuous eccentric contractions are executed. One consequence of this proposed transient Piezo2 microinjury could be a VGLUT1/Ia synaptic disconnection on motoneurons, as we can learn from platinum-analogue chemotherapy. A secondary, harsher injury phase with the involvement of polymodal Aδ and nociceptive C-fibers could follow the primary impairment of proprioception of delayed onset muscle soreness. Repetitive reinjury of these channels in the form of repeated bout effects is proposed to be the tertiary injury phase. Notably, the use of proprioception is associated with motor learning and memory. The impairment of the monosynaptic static phase firing sensory encoding of the affected stretch reflex could be the immediate consequence of the proposed Piezo2 microdamage leading to impaired proprioception, exaggerated contractions and reduced range of motion. These transient Piezo2 channelopathies in the primary afferent terminals could constitute the critical gateway to the pathophysiology of delayed onset muscle soreness. Correspondingly, fatiguing eccentric contraction-based pathological hyperexcitation of the Type Ia afferents induces reactive oxygen species production-associated neuroinflammation and neuronal activation in the spinal cord of delayed onset muscle soreness. [ABSTRACT FROM AUTHOR]

An animal study demonstrated that 6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC), a major bioactive compound in Japanese pungent spice wasabi, has an action of inhibiting the activation of calpain-1 (a protease). Increases in calpain activity can cause continual strength loss after eccentric exercise. It remains to be determined in humans whether 6-MSITC intake would modulate calpain and/or muscle damage responses after eccentric exercise. We performed a randomized, double-blind, crossover design study wherein eight healthy young males were randomly assigned to ingest 9 mg/day of 6-MSITC or placebo from 1 day before exercise to 4 days after exercise (30 maximal isokinetic eccentric contractions of the elbow flexors using an isokinetic dynamometer). Calpain-1 concentration, inflammatory and muscle damage markers (creatine kinase activity, urinary titin concentration, muscle strength, range of motion, muscle soreness and transverse relaxation time) were assessed. Plasma calpain-1 concentration after eccentric exercise was similar between the placebo- and 6-MSITC-treated conditions. All muscle damage and inflammatory markers were not affected by 6-MSITC relative to those in the placebo-treated condition. Our results suggest that 6-MSITC has no effect on plasma calpain-1 concentration and muscle damage and inflammatory markers measured after eccentric exercise. [ABSTRACT FROM AUTHOR]

The pathophysiology of delayed onset muscle soreness is not entirely known. It seems to be a simple, exercise-induced delayed pain condition, but has remained a mystery for over 120 years. The buildup of lactic acid used to be blamed for muscle fatigue and delayed onset muscle soreness; however, studies in the 1980s largely refuted the role of lactate in delayed onset muscle soreness. Regardless, this belief is widely held even today, not only in the general public, but within the medical and scientific community as well. Current opinion is highlighting lactate's role in delayed onset muscle soreness, if neural dimension and neuro-energetics are not overlooked. By doing so, lactate seems to have an essential role in the initiation of the primary damage phase of delayed onset muscle soreness within the intrafusal space. Unaccustomed or strenuous eccentric contractions are suggested to facilitate lactate nourishment of proprioceptive sensory neurons in the muscle spindle under hyperexcitation. However, excessive acidosis and lactate could eventually contribute to impaired proprioception and increased nociception under pathological condition. Furthermore, lactate could also contribute to the secondary damage phase of delayed onset muscle soreness in the extrafusal space, primarily by potentiating the role of bradykinin. After all, neural interpretation may help us to dispel a 40-year-old controversy about lactate's role in the pathophysiology of delayed onset muscle soreness. [ABSTRACT FROM AUTHOR]

Osteoporosis is a disorder, with a largely unknown pathomechanism, that is often marked as a "silent thief", because it usually only becomes undisguised when fractures occur. This implies that the pathological damage occurs earlier than the sensation of pain. The current authors put forward a non-contact injury model in which the chronic overloading of an earlier autologously microinjured Piezo2 ion channel of the spinal proprioceptor terminals could lead the way to re-injury and earlier aging in a dose-limiting and threshold-driven way. As a result, the aging process could eventually lead the way to the metabolic imbalance of primary osteoporosis in a quad-phasic non-contact injury pathway. Furthermore, it is emphasised that delayed onset muscle soreness, non-contact anterior cruciate injury and osteoporosis could have the same initiating proprioceptive non-contact Piezo2 channelopathy, at different locations, however, with different environmental risk factors and a different genetic predisposition, therefore producing different outcomes longitudinally. The current injury model does not intend to challenge any running pathogenic theories or findings, but rather to highlight a principal injury mechanism. [ABSTRACT FROM AUTHOR]

OBJECTIVES Delayed onset muscle soreness (DOMS) is discomfort that occurs within 8-24hrs following an unaccustomed bout of physical activity that peaks within 24-27hrs and slowly resolves on its own. White willow bark (WWB) is a nutritional supplement that is believed to have anti-inflammatory and analgesic properties like aspirin but without the risk of GI adverse effects. The purpose of this investigation is to determine the effectiveness of WWB on alleviating the symptoms of DOMS following exercise. METHODS Twenty-five individuals volunteered to participate and were randomly assigned to take WWB (798mg salicin) or placebo for 5 days following a lower body resistance training session which consisted of 5X10 lunges at 40% body weight (BW) and 3X fatigue leg press at 75%BW. Test procedures included visual analog scale (VAS), mid-thigh circumference and pressure pain threshold. VAS was measured pre, all five days of the supplementation period and day 6 (post-supplementation). All other variables were measured at pre, immediate, day 3(72hrs), and day 6 (post-supplementation). RESULTS No condition X time interaction was observed (p > 0.05) for any variable. However, VAS scores were lower in the WWB compared to the placebo for all time frames. There was a significant main effect of time for VAS scores indicating muscle soreness for hamstrings (p < 0.001), gluteal (p < 0.001), gastrocnemius (p < 0.001) and quadriceps (p < 0.001). In addition, there was a significant main effect of time for right midthigh pressure pain threshold (p = 0.02), mid-right (p < 0.001) and mid-left (p < 0.001) thigh circumference. CONCLUSIONS WWB may reduce subjective feelings of muscle soreness and appears to have analgesic properties.

Abstract Background Delayed onset muscle soreness (DOMS) is a common non-structural muscle injury which can disrupt training and impair performance in elite athletes. Vibration therapy reduces inflammation and improves neuromuscular efficiency, leading to reductions in pain and stiffness, and may be effective for the prevention or treatment of DOMS. However, the effect of whole-body vibration (WBV) used after sport in elite athletes has not been reported. Methods A randomised, controlled trial was performed. Participants were elite (national or international level) hockey players and underwent an eccentric exercise protocol previously shown to produce clinical DOMS. After exercise, one group underwent static stretching with WBV therapy, and the other performed stretching only. Baseline and serial post-exercise pain scores and measurements of quadriceps tightness were obtained. Results Eleven participants were recruited into each study arm. There were no significant differences in baseline group characteristics. Participants receiving WBV had significant reductions in both pain (p = 0.04) and quadriceps tightness (p = 0.02) compared with stretching only. Conclusions Post-exercise WBV is effective in elite hockey players to reduce DOMS after eccentric exercise. Elite athletes in multi-sprint sports are at risk of DOMS during training and competition, and its reduction could contribute to reduced injury risk and improved performance. This treatment modality is favourable because it can be incorporated with minimal disruption into the recovery section of existing training regimes. These findings may also be extrapolated to other multi-sprint sports.