Markers Of Exercise-induced Muscle Damage Research Articles

The Effect of Creatine Supplementation on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials.

This systematic review and meta-analysis examined the effects of creatine supplementation on recovery from exercise-induced muscle damage, and is reported according to the PRISMA guidelines. MEDLINE and SPORTDiscus were searched for articles from inception until April 2020. Inclusion criteria were adult participants (≥18 years); creatine provided before and/or after exercise versus a noncreatine comparator; measurement of muscle function recovery, muscle soreness, inflammation, myocellular protein efflux, oxidative stress; range of motion; randomized controlled trials in humans. Thirteen studies (totaling 278 participants; 235 males and 43 females; age range 20-60 years) were deemed eligible for analysis. Data extraction was performed independently by both authors. The Cochrane Collaboration Risk of Bias Tool was used to critically appraise the studies; forest plots were generated with random-effects model and standardized mean differences. Creatine supplementation did not alter muscle strength, muscle soreness, range of motion, or inflammation at each of the five follow-up times after exercise (<30min, 24, 48, 72, and 96hr; p > .05). Creatine attenuated creatine kinase activity at 48-hr postexercise (standardized mean difference: -1.06; 95% confidence interval [-1.97, -0.14]; p = .02) but at no other time points. High (I2; >75%) and significant (Chi2; p < .01) heterogeneity was identified for all outcome measures at various follow-up times. In conclusion, creatine supplementation does not accelerate recovery following exercise-induced muscle damage; however, well-controlled studies with higher sample sizes are warranted to verify these conclusions. Systematic review registration (PROSPERO CRD42020178735).

The time course of recovery of indirect markers of exercise-induced muscle damage induced by multi- and single-joint exercises

Strength training is performed using multi-joint (MJ) or single-joint (SJ) exercises; however, it is not clear whether different time of recovery is necessary between the two types of exercise. The aim of the present study was to compare the time course of recovery of indirect markers of exercise-induced muscle damage (EIMD) in the elbow flexors after performing MJ and SJ exercises. Twenty-four (n = 24) untrained men were randomized in to the MJ (n = 12) or SJ group (n = 12). Exercise protocol to induce muscle damage consisted of four sets of ten repetitions at 80% of one repetition maximum (1RM) in front pull-down (MJ exercise) or biceps curl (SJ exercise). Maximal voluntary isometric contraction, muscle soreness during elbow extension, ultrasound imaging (muscle thickness and echo intensity) and creatine kinase (CK) were measured before and up to 96 h after exercise. Significant effect of time (p < 0.05) at all times after exercise was observed for isometric strength, muscle soreness, muscle thickness and at 48, 72 and 96 h for echo intensity, with no time × group interaction. However, significant time × group interaction (p = 0.03) was observed only for CK activity at 96 h (MJ = 3348 ± 2911 IU/l vs. SJ = 890 ± 1426 IU/l; p < 0.05). In addition, there was a significant increase in CK after MJ at 48 h, 72 h and 96 h after exercise (p < 0.05), while SJ increased only at 48 h after exercise. Despite a dissimilar time course of CK response, MJ and SJ exercises induced a similar recovery pattern for muscle strength, thickness, echo intensity and soreness.

Moderate intensity cycling is better than running on recovery of eccentric exercise-induced muscle damage

ObjectiveTo compare the effects of moderate intensity running and cycling on markers of exercise-induced muscle damage in men. Study designRandomized controlled trial. SettingLaboratory. ParticipantsThirty volunteers were randomized in three groups [running (RG; n = 10), cycling (CG; n = 10) and control (CON; n = 10)] and were evaluated at baseline, post 24, 48 and 72 h of knee extensors’ muscle damage protocol. CON performed passive recovery, while RG and CG performed active recovery immediately after the protocol, as well as 24 h and 48 h afterwards. Main outcomes(i) maximal voluntary isometric contraction (MVIC); (ii) delayed-onset muscle soreness (DOMS); (iii) plasma creatine kinase (CK) and lactate dehydrogenase (LDH) levels. ResultsNo group-by-time interaction was found in any outcome evaluated (p > 0.05). All groups presented decreases in MVIC and increases in DOMS (p < 0.001), without differences in CK and LDH. Compared with CON, exercise groups presented likely beneficial effects for LDH, while only CG had a likely beneficial effect for DOMS. Lastly, CG presented likely/very likely beneficial effects for MVIC and DOMS compared to RG. ConclusionAlthough the null hypothesis analysis did not find differences, the magnitude-based inference analysis suggested that moderate intensity cycling have likely beneficial effects on knee extensor muscle recovery after eccentric exercise protocol.

Effects of Individualized Ischemic Preconditioning on Protection Against Eccentric Exercise-Induced Muscle Damage: A Randomized Controlled Trial.

The effects of ischemic preconditioning (IPC) versus a deceptive sham protocol on indirect markers of exercise-induced muscle damage (EIMD) after the application of individualized occlusion pressure were examined. The goal of using a sham protocol is to control for the potential effect of placebo. IPC would surpass the sham protocol in protecting against EIMD. A randomized, double-blinded, clinical trial. Level 1. Thirty healthy young men were randomly assigned to an eccentric exercise for the knee extensor muscles preceded by IPC (4 × 5 minutes of individualized total occlusion pressure) or sham protocol (4 × 5 minutes using 20 mm Hg). Maximal voluntary isometric torque (MVIT), rate of torque development, muscle soreness, pressure pain threshold, knee range of motion, thigh girth, and creatine kinase (CK) activity were assessed before IPC or sham protocol and up to 72 hours after the eccentric EIMD. Affective valence and perceived exertion were also evaluated. MVIT decreased 17.1% in the IPC and 18.1% in the sham groups, with no differences between groups. Differences from baseline were observed in the sham group for muscle soreness at 48 hours (P < 0.001) and 72 hours (P = 0.02), and for CK activity at 72 hours (P = 0.04). Muscle soreness was reduced in the IPC group at 48 hours compared with the sham group (∆ = 15.8 mm; P = 0.008) but without achieving the minimal clinically important difference. IPC induced a smaller perceived exertion than the sham protocol (∆ = 1.1 a.u.; P = 0.02). The remaining outcomes were not statistically different in both groups. IPC does not surpass the sham protocol to protect against mild EIMD of the knee extensors muscles. Although IPC is a noninvasive, low-cost, and easy-to-administer intervention, the IPC effects can, in part, be explained by the placebo effect. In addition, individualized IPC promotes attenuation in perceived exertion during eccentric exercise.

Effect of whey vs. soy protein supplementation on recovery kinetics following speed endurance training in competitive male soccer players: a randomized controlled trial

BackgroundSoccer-specific speed-endurance training induces short-term neuromuscular fatigue and performance deterioration over a 72-h recovery period, associated with elevated markers of exercise-induced muscle damage. We compared the effects of whey vs. soy protein supplementation on field activity, performance, muscle damage and redox responses following speed-endurance training in soccer players.MethodsTen well-trained, male soccer players completed three speed-endurance training trials, receiving whey protein (WP), soy protein (SP) or an isoenergetic placebo (PL; maltodextrin) according to a randomized, double-blind, crossover, repeated-measures design. A pre-loading period was applied in each trial during which protein supplementation was individually adjusted to reach a total protein intake of 1.5 g/kg/day, whereas in PL protein intake was adjusted at 0.8–1 g/kg/day. Following pre-loading, two speed-endurance training sessions (1 and 2) were performed 1 day apart, over a 3-day experimental period. During each session, field activity and heart rate were continuously monitored using global positioning system and heart rate monitors, respectively. Performance (isokinetic strength of knee extensors and flexors, maximal voluntary isometric contraction, speed, repeated sprint ability, countermovement jump), muscle damage (delayed-onset of muscle soreness, creatine kinase activity) and redox status (glutathione, total antioxidant capacity, protein carbonyls) were evaluated at baseline (pre), following pre-loading (post-load), and during recovery from speed-endurance training.ResultsHigh-intensity and high-speed running decreased (P ≤ 0.05) during speed-endurance training in all trials, but WP and SP mitigated this response. Isokinetic strength, maximal voluntary isometric contraction, 30-m speed, repeated sprint ability and countermovement jump performance were similarly deteriorated during recovery following speed-endurance training in all trials (P ≤ 0.05). 10 m speed was impaired at 24 h only in PL. Delayed-onset of muscle soreness, creatine kinase, total antioxidant capacity and protein carbonyls increased and glutathione decreased equally among trials following speed-endurance training (P ≤ 0.05), with SP inducing a faster recovery of protein carbonyls only at 48 h (P ≤ 0.05) compared to WP and PL.ConclusionsIn conclusion, increasing daily protein intake to 1.5 g/kg through ingestion of either whey or soy protein supplements mitigates field performance deterioration during successive speed-endurance training sessions without affecting exercise-induced muscle damage and redox status markers.Trial registrationName of the registry: clinicaltrials.gov. Trial registration: NCT03753321. Date of registration: 12/10/2018.

Effectiveness of a combined New Zealand green-lipped mussel and Antarctic krill oil supplement on markers of exercise-induced muscle damage and inflammation in untrained men

Green-lipped mussel oil (PCSO-524®) has been shown to attenuate signs and symptoms of exercise-induced muscle damage (EIMD), and krill oil has been shown to have a protective effect against cytokine-induced tissue degradation. The purpose of this study was to compare the effects of PCSO-524® and ESPO-572® (75% PCSO-524® and 25% krill oil) on signs and symptoms of EIMD. Fifty-one untrained men consumed 600 mg/d of PCSO-524® (n = 24) or ESPO-572® (n = 27) for 26 d prior to and 72 h following a downhill running bout. Delayed onset muscle soreness (DOMS), pressure pain threshold, limb swelling, range of motion (ROM), isometric torque, and blood markers of inflammation and muscle damage were assessed at baseline, 24, 48 and 72 h post-eccentric exercise. ESPO-572® was ‘at least as good as’ PCSO-524® and both blends were superior (p < 0.05) to placebo in lessening the increase in DOMS at 24, 48, 72 h. ESPO-572® and PCSO-524® were protective against joint ROM loss compared to placebo (p < 0.05) at 48 and 72 h. Notably, at 24 and 48 h, joint ROM was higher in the ESPO-572® compared to the PCSO-524® group (p < 0.05). No differences between the two blends for the other markers were found. ESPO-572® is ‘at least as good’ as PCSO-524® in reducing markers of muscle damage and soreness following eccentric exercise and was superior to PCSO-524® in protecting against the loss in joint ROM during recovery. Our data support the use of ESPO-572®, a combination of green-lipped mussel and krill oil, in mitigating the deleterious effects of EIMD.

Effects of ischemic preconditioning on indirect markers of exercise-induced muscle damage: protocol for a randomized placebo-controlled trial

Background: Ischemic preconditioning (IPC) has been used to improve exercise performance, but its role in protecting against exercise-induced muscle damage (EIMD) is still unclear. Objective: To investigate the effects of IPC on the indirect markers of EIMD when compared to placebo. Methods: 30 healthy young men, with no recent experience in lower limb strength training, will be recruited. Subjects will be allocated randomly into two groups: IPC or placebo. The IPC group will undergo 4 x 5 min of occlusion (with individualized total occlusion pressure), interspersed with 5 min of reperfusion. The placebo group will be submitted to the same protocol, but with minimum pressure (10mmHg) being applied during the occlusion period. After the interventions, volunteers will be submitted to muscle damage induced by isokinetic exercise (10 sets of 12 maximum eccentric repetitions) in the non-dominant femoral quadriceps. The primary outcome will be isometric peak torque, measured both before and up to 72 hours after exercise. Secondary outcomes include rate of torque development, muscle soreness, knee range of motion, thigh circumference and blood levels of creatine kinase. Discussion: The results of this trial will indicate whether the effects of IPC are superior to placebo in the protection against EIMD

The Effects Of Foam Rolling On Exercise Induced Muscle Damage

Exercise-induced muscle damage (EIMD) occurs following strenuous and unaccustomed exercise. EIMD is associated with elevated creatine kinase (CK) blood concentrations, limitations in range of motion (ROM), and cellular swelling. EIMD may negatively affect training quality and performance thus methods to mitigate EIMD may be useful to resistance training populations. Self-myofascial release, in particular foam rolling (FR), has been utilized by competitive and recreational athletes to ameliorate the effects of EIMD. However, the effect of FR on EIMD has yet to be established. PURPOSE: The purpose of this study is to investigate the effect of FR on markers of EIMD after an acute bout of high volume resistance exercise. METHODS: Eight participants (five males and three females), between the ages of 18 and 35, completed two acute resistance exercise bouts (10 sets of 10 repetitions barbell back squat at 60% 1RM) separated by a minimum of seven days. Following one exercise bout, subjects performed FR targeting the thigh (i.e hamstrings and quadriceps), the shank (i.e. calf and tibialis anterior), and the gluteus maximus immediately post, 24, and 48 hours post exercise, while no FR was performed following the alternate bout (CON). In both conditions, participants were asked to refrain from additional recovery methods following exercise. Outcome measures included serum CK, hip ROM, knee ROM, and thigh circumference. All measurements were pre-exercise, immediately post, 24, and 48 hours post. RESULTS: There was a significant increase in serum CK from pre to 24 hours post (p = 0.04), as well as 24 and 48 hours post (p = 0.04). Hip ROM (p = 0.02) and knee ROM (p = 0.03) decreased and thigh circumference (p = 0.03) increased 48 hours post exercise. No significant differences between FR and CON were found for any measures. CONCLUSION: FR does not attenuate markers of muscle damage (i.e. serum CK, hip ROM, knee ROM, and thigh circumference) after an acute bout of high volume resistance training. This study suggests that despite its common practice, FR may not be an effective strategy for mitigating EIMD.

Exercise-Induced Muscle Damage and Cardiac Stress During a Marathon Could be Associated with Dietary Intake During the Week Before the Race

Adequate food intake is important prior to endurance running competitions to facilitate adequate exercise intensity. However, no investigations have examined whether dietary intake could prevent exercise-induced muscle damage (EIMD) and cardiac stress (EICS). Thus, this study’s objective was to determine the associations between EIMD, EICS and endurance athlete diets one week before a marathon race. Sixty-nine male runners participated in this study. Food intake during the week prior to the race was collected through a seven-day weighed food record. Dietary intake on race day was also recorded. At the end of the marathon, blood samples were drawn to determine serum creatine kinase (CK) and myoglobin, and muscle–brain isoform creatine kinase (CK-MB), prohormone of brain natriuretic peptide (NT-proBNP), cardiac troponin I (TNI), and cardiac troponin T (TNT) concentration as markers of EIMD and EICS, respectively. To determine the association between these variables, a stepwise regression analysis was carried out. The dependent variable was defined as EIMD or EICS and the independent variables were defined as the number of servings within each different food group. Results showed that the intake of meat during the previous week was positively associated with post-race CK (Standardized Coefficients (β) = 0.643; p < 0.01) and myoglobin (β = 0.698; p < 0.001). Vegetables were negatively associated the concentration of post-race CK (β = −0.482; p = 0.002). Butter and fatty meat were positively associated with NT-proBNP (β = 0.796; p < 0.001) and TNI (β = 0.396; p < 0.001) post-marathon values. However, fish intake was negatively associated with CK (β = −0.272; p = 0.042), TNI (β = −0.593; p < 0.001) and TNT (β = −0.640; p = 0.002) post-marathon concentration. Olive oil was negatively associated with TNI (β = −0.536; p < 0.001) and TNT (β = −0.415; p = 0.021) values. In conclusion, the consumption of meat, butter, and fatty meat might be associated with higher levels of EIMD and EICS. On the other hand, fish, vegetables, and olive oil might have a protective role against EIMD and EICS. The selection of an adequate diet before a marathon might help to reduce some of the acute burdens associated with marathon races.

Long-Term Effect of Combination of Creatine Monohydrate Plus β-Hydroxy β-Methylbutyrate (HMB) on Exercise-Induced Muscle Damage and Anabolic/Catabolic Hormones in Elite Male Endurance Athletes.

Creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are widely studied ergogenic aids. However, both supplements are usually studied in an isolated manner. The few studies that have investigated the effect of combining both supplements on exercise-induced muscle damage (EIMD) and hormone status have reported controversial results. Therefore, the main purpose of this study was to determine the effect and degree of potentiation of 10 weeks of CrM plus HMB supplementation on EIMD and anabolic/catabolic hormones. This study was a double-blind, placebo-controlled trial where participants (n = 28) were randomized into four different groups: placebo group (PLG; n = 7), CrM group (CrMG; 0.04 g/kg/day of CrM; n = 7), HMB group (HMBG; 3 g/day of HMB; n = 7), and CrM-HMB group (CrM-HMBG; 0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before (baseline, T1) and after 10 weeks of supplementation (T2), blood samples were collected from all rowers. There were no significant differences in the EIMD markers (aspartate aminotransferase, lactate dehydrogenase, and creatine kinase) among groups. However, we observed significant differences in CrM-HMBG with respect to PLG, CrMG, and HMBG on testosterone (p = 0.006; η2p = 0.454) and the testosterone/cortisol ratio (T/C; p = 0.032; η2p = 0.349). Moreover, we found a synergistic effect of combined supplementation on testosterone (CrM-HMBG = −63.85% vs. CrMG + HMBG = −37.89%) and T/C (CrM-HMBG = 680% vs. CrMG + HMBG = 57.68%) and an antagonistic effect on cortisol (CrM-HMBG = 131.55% vs. CrMG + HMBG = 389.99%). In summary, the combination of CrM plus HMB showed an increase in testosterone and T/C compared with the other groups after 10 weeks of supplementation. Moreover, this combination presented a synergistic effect on testosterone and T/C and an antagonistic effect on cortisol compared with the sum of individual or isolated supplementation.

Effect of the Combination of Creatine Monohydrate Plus HMB Supplementation on Sports Performance, Body Composition, Markers of Muscle Damage and Hormone Status: A Systematic Review.

Although there are many studies showing the isolated effect of creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB), it is not clear what effect they have when they are combined. The main purpose of this systematic review was to determine the efficacy of mixing CrM plus HMB in comparison with their isolated effects on sports performance, body composition, exercise induced markers of muscle damage, and anabolic-catabolic hormones. This systematic review was carried out in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement guidelines and the PICOS model, for the definition of the inclusion criteria. Studies were found by searching PubMed/MEDLINE, Web of Science (WOS), and Scopus electronic databases from inception to July 3rd 2019. Methodological quality and risk of bias were assessed by two authors independently, and disagreements were resolved by third-party evaluation, in accordance with the Cochrane Collaboration Guidelines samples. The literature was examined regarding the effects of the combination of CrM plus HMB on sport performance using several outcome variables (athletic performance, body composition, markers of muscle damage, and hormone status). This systematic review included six articles that investigated the effects of CrM plus HMB on sport performance (two on strength performance, showing improvements in one of them; three on anaerobic performance, presenting enhancements in two of them; and one on aerobic performance, not presenting improvements), body composition (three on body mass, showing improvements in one of them; two on fat free mass, presenting increases in one of them; and two on fat mass, showing decreases in one of them) and markers of muscle damage and hormone status (four on markers of muscle damage and one on anabolic-catabolic hormones, not showing benefits in any of them). In summary, the combination of 3–10 g/day of CrM plus 3 g/day of HMB for 1–6 weeks could produce potential positive effects on sport performance (strength and anaerobic performance) and for 4 weeks on body composition (increasing fat free mass and decreasing fat mass). However, this combination seems to not show positive effects relating to markers of exercise-induced muscle damage and anabolic-catabolic hormones.

Consumption of An Anthocyanin-Rich Antioxidant Juice Accelerates Recovery of Running Economy and Indirect Markers of Exercise-Induced Muscle Damage Following Downhill Running.

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

No Effect of Tart Cherry Juice or Pomegranate Juice on Recovery from Exercise-Induced Muscle Damage in Non-Resistance Trained Men.

Tart cherry juice (TC) and pomegranate juice (POM) have been demonstrated to reduce symptoms of exercise-induced muscle damage (EIMD), but their effectiveness has not been compared. This randomized, double-blind, parallel study compared the effects of TC and POM on markers of EIMD. Thirty-six non-resistance trained men (age 24.0 (Interquartile Range (IQR) 22.0, 33.0) years, body mass index (BMI) 25.6 ± 4.0 kg·m−2) were randomly allocated to consume 2 × 250 mL of: TC, POM, or an energy-matched fruit-flavored placebo drink twice daily for nine days. On day 5, participants undertook eccentric exercise of the elbow flexors of their non-dominant arm. Pre-exercise, immediately post-exercise, and at 24 h, 48 h, 72 h and 96 h post-exercise, maximal isometric voluntary contraction (MIVC), delayed onset muscle soreness (DOMS), creatine kinase (CK), and range of motion (ROM) were measured. The exercise protocol induced significant decreases in MIVC (p < 0.001; max decrease of 26.8%, 24 h post-exercise) and ROM (p = 0.001; max decrease of 6.8%, 72 h post-exercise) and significant increases in CK (p = 0.03; max increase 1385 U·L−1, 96 h post-exercise) and DOMS (p < 0.001; max increase of 26.9 mm, 48 h post-exercise). However, there were no statistically significant differences between treatment groups (main effect of group p > 0.05 or group x time interaction p > 0.05). These data suggest that in non-resistance trained men, neither TC nor POM enhance recovery from high-force eccentric exercise of the elbow flexors.

Investigation of the Impact of Below-Knee Compression Garments on Markers of Exercise-Induced Muscle Damage and Performance in Endurance Runners: A Prospective Randomized Controlled Trial.

Compression garment utilization is very popular among runners despite a lack of consensus in the literature regarding a beneficial impact. The aim of the study was to investigate the impact of training and competing with compression garments on exercise-induced muscle damage and performance in ultramarathon runners. Compression garments will reduce the severity of exercise-induced muscle damage and improve performance in long-distance runners compared with control conditions. Prospective, randomized controlled trial. Level 1. The study was conducted in healthy, uninjured endurance runners (n = 41) participating in a 56-km ultramarathon. The experimental group (n = 20; 14 males, 6 females) trained for 6 weeks and participated in the race wearing below-knee compression garments while the control group (n = 21; 15 males, 6 females) did not. Participants were tested on 4 occasions for various markers of exercise-induced muscle damage and running performance. Ankle circumference measurements increased significantly less ( P = 0.01, Cohen d = 0.9) in the experimental group from immediately after until 2 days post-race compared with the control group. No further statistically significant changes were detected over time in midcalf circumferences, muscle architecture, or race performance. Selected pain ratings were statistically significant and worse in the experimental group. There are limited indications of a beneficial impact of compression garments with improvements in ankle circumference measurements. No ergogenic impact was detected. There is limited evidence to support the continued utilization of commercially available below-knee compression garments during running for the purpose of muscle recovery or as a performance aid.

Stretch imposed on active muscle elicits positive adaptations in strain risk factors and exercise-induced muscle damage.

Stretching highly-contracted plantar flexor muscles (isokinetic eccentric contractions) results in beneficial adaptations in muscle strain risk factors; however its effects in other muscle groups, and on architectural characteristics and exercise-induced muscle damage (EIMD), are unknown. The influence of a 6-week knee extensor training program was studied in 26 volunteers (13 control; 13 experimental). Before and after the training program, passive and maximal isometric and eccentric knee extensor moments and range of motion (ROM) were recorded on an isokinetic dynamometer with simultaneous ultrasound imaging of vastus lateralis (VL). On a separate day, EIMD markers (creatine kinase [CK], delayed onset muscle soreness [DOMS]) were measured before and 24hours after a 20-minute downhill run. The 6-week training program was performed twice-weekly where five sets of 12 stretches (3seconds per stretch) were imposed on maximally contracted knee extensor muscles. Significant (P<0.05) increases in eccentric (29.5%) and isometric (17.4%) moments, ROM (5.2°), stretch tolerance (55.4%), elastic energy storage (73.0%), VL thickness (7.8%), pennation angle (9.0%), and tendon stiffness (8.7%) occurred. No change (P>0.05) in passive muscle-tendon stiffness (-9.4%) or resting fascicle length (-0.7%) occurred. The downhill run resulted in substantial DOMS and significant increase in CK concentration before the training program (107.6%); however, DOMS was eliminated from the knee extensors and a significantly smaller increase in CK (-70.0%) occurred post-training. Positive adaptations in functional and physiological variables confirm that imposing stretch on maximally contracted muscle provides beneficial adaptations likely to mitigate EIMD and injury risk and enhance functional performance.

The Impact of Soccer Match Play on the Muscle Damage Response in Youth Female Athletes.

Post-match assessment of creatine kinase (CK) activity and delayed-onset muscle soreness (DOMS) are common markers of exercise-induced muscle damage and recovery status in soccer players. These responses have not been examined in youth female players. This study examined the effect of competitive match play on CK activity and DOMS in elite youth players. Thirty-four elite female players, divided into three chronological age groups (U13, n=11; U15, n=10; U17 n=12). Players completed baseline testing for CK and DOMS that was repeated immediately (for DOMS), 80, 128 and 168 h post-competitive match play for CK. Significant time effects were reported for CK (P=0.006) and DOMS (P<0.01). Significant differences between baseline and 168 h post-match were reported for CK (P<0.01), with significant group differences between the U13 and U17 groups for CK (P<0.01). All parameters returned to baseline in U17s at 168 h, but increased CK was evident for U13s and U15s at 168 h. In conclusion, seven days may be insufficient for biochemical recovery in youth female athletes. Therefore, monitoring strategies to assess muscle damage between training and match play should be considered to track recovery and potentially reduce muscular injury risk.

Influence of different types of compression garments on exercise-induced muscle damage markers after a soccer match

ABSTRACTThere is not enough evidence of positive effects of compression therapy on the recovery of soccer players after matches. Therefore, the objective was to evaluate the influence of different types of compression garments in reducing exercise-induced muscle damage (EIMD) during recovery after a friendly soccer match. Eighteen semi-professional soccer players (24 ± 4.07 years, 177 ± 5 cm; 71.8 ± 6.28 kg and 22.73 ± 1.81 BMI) participated in this study. A two-stage crossover design was chosen. Participants acted as controls in one match and were assigned to an experimental group (compression stockings group, full-leg compression group, shorts group) in the other match. Participants in experimental groups played the match wearing the assigned compression garments, which were also worn in the 3 days post-match, for 7 h each day. Results showed a positive, but not significant, effect of compression garments on attenuating EIMD biomarkers response, and inflammatory and perceptual responses suggest that compression may improve physiological and psychological recovery.

Muscle-Tendon Unit Properties during Eccentric Exercise Correlate with the Creatine Kinase Response.

Aim: The aim of this paper was to determine whether; (1) patella tendon stiffness, (2) the magnitude of vastus lateralis fascicle lengthening, and (3) eccentric torque correlate with markers of exercise induced muscle damage.Method: Combining dynamometry and ultrasonography, patella tendon properties and vastus lateralis architectural properties were measured pre and during the first of six sets of 12 maximal voluntary eccentric knee extensions. Maximal isometric torque loss and creatine kinase activity were measured pre-damage (−48 h), 48, 96, and 168 h post-damage as markers of exercise-induced muscle damage.Results: A significant increase in creatine kinase (883 ± 667 UL) and a significant reduction in maximal isometric torque loss (21%) was reported post-eccentric contractions. Change in creatine kinase from pre to peak significantly correlated with the relative change in vastus lateralis fascicle length during eccentric contractions (r = 0.53, p = 0.02) and with eccentric torque (r = 0.50, p = 0.02). Additionally, creatine kinase tended to correlate with estimated patella tendon lengthening during eccentric contractions (p < 0.10). However, creatine kinase did not correlate with resting measures of patella tendon properties or vastus lateralis properties. Similarly, torque loss did not correlate with any patella tendon or vastus lateralis properties at rest or during eccentric contractions.Conclusion: The current study demonstrates that the extent of fascicle strain during eccentric contractions correlates with the magnitude of the creatine kinase response. Although at rest, there is no relationship between patella tendon properties and markers of muscle damage; during eccentric contractions however, the patella tendon may play a role in the creatine kinase response following EIMD.

Oral contraceptive pill use and the susceptibility to markers of exercise-induced muscle damage

PurposeFirstly, to establish whether oral contraceptive pill (OCP) users are more susceptible to muscle damage compared to non-users, and secondly, to establish whether differences can be attributed to differences in patella tendon properties.MethodsNine female OCP users and 9 female non-users participated in the investigation. Combining dynamometry, electromyography and ultrasonography, patella tendon properties and vastus lateralis architectural properties were measured pre and during the first of 6 sets of 12 maximal voluntary eccentric knee extensions. Serum oestrogen levels were measured on the 7th day of the pill cycle and the 14th day of menstrual cycle in OCP users and non-users, respectively. Maximal voluntary isometric knee extension torque loss, creatine kinase and muscle soreness were measured 48 h pre-damage, post-damage, and 48, 96 and 168 h post-damage.ResultsOestrogen levels were significantly lower in OCP users compared to non-users (209 ± 115 and 433 ± 147 pg/ml, respectively, p = 0.004). Proposed determinants of muscle damage, patella tendon stiffness and maximal eccentric torque did not differ between OCP users and non-users. The change in creatine kinase from pre to peak was significantly higher in OCP users compared to non-users (962 ± 968 and 386 ± 474 Ul, respectively, p = 0.016). There were no other differences in markers of muscle damage.ConclusionAlthough our findings suggest that, when compared to non-users, the OCP may augment the creatine kinase response following eccentric exercise, it does not increase the susceptibility to any other markers of muscle damage.

Fascicle Lengthening During Eccentric Exercise Determines The Magnitude Of Muscle Damage

The characteristics of the muscle-tendon interaction during eccentric contractions suggests that tendon properties and the magnitude of fascicle lengthening contribute to the extent and the variability of exercise-induced muscle damage (EIMD). The mechanical processes which predispose the severity of EIMD remains unclear. PURPOSE: To determine whether; 1) patella tendon stiffness, at rest and during eccentric contractions, 2) the magnitude of vastus lateralis (VL) fascicle lengthening during eccentric contractions, and/or 3) eccentric torque, are determinants of EIMD. METHODS: Combining dynamometry, electromyography and ultrasonography, patella tendon properties and VL architectural properties were measured pre and during the first of 6 sets of 12 maximal voluntary eccentric knee extensions (range of motion 20 - 90°, 0° = full extension). The eccentric phase of the contraction was performed at an isokinetic angular velocity of 30°s-1 and the concentric phase was performed passively at an angular velocity of 60°s-1. Maximal isometric torque loss and creatine kinase (CK) activity were measured pre-damage (-48 h), 48, 96 and 168 h post-damage as markers of EIMD. RESULTS: Compared to pre-damage, a significant reduction in maximal isometric torque (264 ± 35 Nm, 221.0 ± 48.4 Nm, p = 0.004) and a significant increase in CK (136 ± 114, 796 ± 723 UL, p = 0.014) was reported 48 and 96 hrs post EIMD respectively. Relative changes in CK correlated with the relative change in fascicle length during eccentric contractions (r = 0.53, p = 0.02) and eccentric torque (r = 0.50, p = 0.02). Additionally, the relative change in CK tended to correlate with estimated patella tendon lengthening during eccentric contractions (r = -0.41, p < 0.10). However, relative change in CK did not correlate with resting measures of patella tendon properties or VL properties. Similarly, torque loss did not correlate with any patella tendon or VL properties at rest or during eccentric contractions. CONCLUSION: The extent of fascicle lengthening during eccentric contractions is related to the magnitude of the CK response. Furthermore, at rest, patella tendon properties are not determinants of indices of EIMD. During eccentric contractions of the VL, the patella tendon might play a modulatory role during exercise, to the susceptibility of EIMD.