Indirect Markers Of Muscle Damage Research Articles

Hormonal Responses after Exercise-induced Muscle Damage in Healthy Humans

Mechanically overloaded muscle and its subsequent damage are strong stimuli for eliciting acute hormonal changes, and muscle adaptation following exercise- induced muscle damage may involve complex hormonal responses before the completion of muscle regeneration. PURPOSE: This study investigated systemic responses of thyroid-stimulating hormone (TSH), free thyroxine (fT4) and prolactin (PRL) for several days after eccentric exercise-induced muscle damage in humans. METHODS: Nine healthy men (age 25.7 ± 1.7 years, height 180.4 ± 1.7 cm, body mass 77.2 ± 2.7 kg, body mass index 23.7 ± 0.6) performed 50 maximal eccentric muscle actions using the knee extensor muscles of both legs on an isokinetic dynamometer. Blood samples were withdrawn before and at 6, 48 and 120 hrs post-exercise, and serum levels of TSH, fT4) and PRL were measured by ELISA using commercially available kits. Myoglobin (Mb) concentration and lactate dehydrogenase (LDH) activity were also evaluated as indirect markers of muscle damage. One-way ANOVA was used for statistics. RESULTS: Significant alterations in Mb and LDH were observed over time after eccentric exercise (p<0.05-0.001). Serum fT4 levels exhibited a gradual increase reaching statistical significance at 48 and 120 hrs following the muscle damaging exercise (1.20±0.05 ng/dl, 1.29±0.04 ng/dl, and 1.26±0.05 ng/dl, at 6, 48 and 120 hours after exercise, respectively, compared to 1.13±0.02 ng/dl at baseline; mean±SE, p<0.05). Both PRL and TSH showed also a gradual increase up to 33% at 48 hrs and 120 hrs post exercise, respectively, however they failed to reach statistical significance due to a large variability shown between the subjects’ responses (PRL: 23.4±3.1 ng/ml, 28.1±4.7 ng/ ml, 30.2±4.1 ng/ml and 25.7±4.6 ng/ml; TSH: 1.09±0.14 μIU/ml, 1.27±0.15 μIU/ml, 1.17±0.20 μIU/ml, and 1.33±0.17 μIU/ml, at baseline, 6, 48 and 120 hours post- exercise, respectively, mean±SE, p>0.05). CONCLUSION: The late elevated levels of TSH and PRL, and particularly of fT4, during the recovery period after muscle damage may suggest functional interactions between those hormones and muscle regeneration. Further studies are needed to characterize the mechanisms by which those hormonal responses are triggered and regulated at the systemic level during recovery after exercise-induced muscle damage.

Effects of Two Maximal Isometric Contractions Attenuate Eccentric Exercise-induced Muscle Damage on Surface Electromyographic Activity

Tseng et al. (2016) reported that changes in MaxECC-induced muscle damage (EIMD) of the preconditioning MVC training of the knee extensors (KE) for untrained men was significantly smaller than control group. No studies have recruited untrained participants, and targeted on hamstring muscle strains in which are the most frequent sporting injuries to clarify whether non-damaging exercise of MVC can be attenuated muscle damage induced by MaxECC of knee flexors (KF). PURPOSE: This study investigated the neural factors (surface electromyography, EMG) of two maximal isometric contractions (2MVC) at 20° knee flexion on changes in indirect muscle damage markers following 60 MaxECC of KF performed 2 days later. METHODS: Sixteen untrained young males were randomly placed into the control group (CON) that did not perform 2MVC, or the experimental group (2d, n = 8 per group) who performed 2MVC 2 days before MaxECC. Changes in muscle soreness (SOR), non-dominant upper thigh circumference (CIR), resting knee angle (RANG), maximal voluntary isokinetic concentric contraction (MVC-CON), and surface EMG [median frequency (MF), root mean square (RMS)] before, immediately after, and 1-5 days after MaxECC were compared between groups by a mixed-design of two-way ANOVA. RESULTS: 1). Significant (p < .05) changes in some dependent variables after 2MVC compared to baseline for the 2d group; 2). Changes in the muscle damage variables (e.g. MVC-CON: -13.1%; CIR: +1.5 mm) following MaxECC immediately for the 2d group were smaller than CON group (-22.4%; +4.8 mm); 3) Changes in the surface EMG activity following MaxECC for the 2d group showed smaller changes (MF: 60.2 ± 9.1 Hz) than CON group (70 ± 13.2 Hz). CONCLUSION: These results suggest that protective effect conferred by non-damaging exercise of 2MVC against subsequent MaxECC-induced muscle damage is likely to be related to neural adaptations. Therefore, the RBE protocol of this study may provide some useful information for men to minimize muscle damage when they start to participate exercise. It is also required to further understand the underpinning mechanisms of the repeated bout effect in both physiological and pathological contexts.

Contralateral Repeated Bout Effect of the Knee Flexors.

Eccentric exercise of the elbow flexors (EF) confers protective effect against muscle damage of the same exercise performed by the opposite arm at 1, 7, or 28 d later. This is known as the contralateral repeated bout effect (CL-RBE), but it is not known whether CL-RBE is evident for the knee flexors (KF). The present study tested the hypothesis that KF CL-RBE would be observed at 1, 7, and 28 d after the initial bout. Young untrained men were assigned to a control or one of three experimental groups (n = 13 per group). The experimental groups performed 60 maximal KF eccentric contractions (60MaxEC) using one leg followed by the same exercise using the opposite leg at 1, 7, or 28 d later. The control group used the nondominant leg to repeat 60MaxEC separated by 14 d. Changes in several indirect muscle damage markers after 60MaxEC were compared between bouts and among the groups by using a mixed-design, two-way ANOVA. Changes in maximal voluntary isokinetic concentric contraction torque, range of motion, muscle soreness, and plasma creatine kinase activity after the first 60MaxEC were similar among the groups. These changes were smaller after the second than the first 60MaxEC for the control, 1-d, and 7-d groups, and the changes after the second 60MaxEC were smaller for the control than for both the 1- and 7-d groups (P < 0.05). When the KF CL-RBE was compared with the EF CL-RBE of the previous study, the magnitude was not significantly different. These results showed that CL-RBE was evident for KF in a similar manner to that for EF, but did not last for 28 d, and the CL-RBE was smaller than the ipsilateral RBE.

Hormonal responses following eccentric exercise in humans.

Mechanically overloaded muscle and its subsequent damage are strong stimuli for eliciting acute hormonal changes, while the muscle adaptation which occurs following exercise-induced muscle damage may involve complex hormonal responses before the completion of muscle regeneration. The purpose of this study was to investigate systemic responses of various hormones, as well as secreted proteins that are exercise-regulated and associated with muscle adaptation, for several days after eccentric exercise-induced muscle damage in humans. Nine young male volunteers performed 50 maximal eccentric muscle actions using the knee extensor muscles of both legs. Blood samples were drawn before and at 6, 48 and 120 hours post exercise and serum levels of growth hormone (GH), insulin-like growth factor binding protein-3 (IGFBP-3), cortisol, prolactin, thyroid-stimulating hormone (TSH), free thyroxine (fT4), irisin, follistatin and sclerostin were measured. Myoglobin (Mb) concentration and lactate dehydrogenase (LDH) activity were also evaluated as indirect markers of muscle damage. Significant alterations in Mb and LDH were observed over time after eccentric exercise (p=0.039-0.001). A late serum increase in fT4 and decrease in irisin levels, along with an early and persistent decrease in IGFBP-3 levels, were observed following the muscle-damaging exercise (p=0.049-0.016). GH, cortisol, prolactin, TSH, follistatin and sclerostin exhibited moderate changes during the recovery period after exercise, though without reaching statistical significance (p>0.05), while correlational analyses revealed significant associationsbetween GH and IGFBP-3, prolactin and sclerostin over time (p=0.049-0.001). The significant hormonal responses observed in this study may indicate their involvement in the regenerative mechanisms following muscle damage, potentially as part of a regulatory network to support a normal adaptation process after muscle-damaging exercise.

Muscle damage protective effect by two maximal isometric contractions on maximal eccentric exercise of the elbow flexors of the contralateral arm.

Muscle damage after 30 maximal eccentric contractions of the elbow flexors (30MVEC) is reduced when the same exercise is performed by the opposite arm, and when two maximal voluntary isometric contractions at a long muscle length (2MVIC) are performed prior to 30MVEC by the same arm. This study investigated the hypothesis that 2MVIC would attenuate muscle damage after 30MVEC performed by the opposite arm. Untrained young (20-25years) men were placed into 1 of 4 experimental groups that performed 2MVIC at 1 (1d), 2 (2d), 4 (4d), or 7days (7d) before 30MVEC by the opposite arm, or one control group that performed 30MVEC only (n=13/group). Changes in indirect muscle damage markers after 30MVEC were compared among the groups by mixed-design two-way ANOVA. Maximal voluntary concentric contraction torque, range of motion, plasma creatine kinase activity, and muscle soreness did not change significantly after 2MVIC. Changes in these variables after 30MVEC were smaller (P<.05) for 1d (eg, peak soreness: 45±21mm) and 2d groups (46±20mm) than control group (66±18mm), without significant differences between 1d and 2d groups. No significant differences in the changes were found among 4d, 7d, and control groups, except for soreness showing smaller (P<.05) increases for 4d group (54±19mm) than 7d (62±17mm) and control groups. These results supported the hypothesis and showed that muscle damage induced by 30MVEC was reduced by 2MVIC performed 1-2days prior to 30MVIC by the contralateral arm.

Influence of Maturation Status on Eccentric Exercise-Induced Muscle Damage and the Repeated Bout Effect in Females.

This study compared changes in indirect muscle damage markers, proprioception and arterial stiffness after elbow flexor eccentric exercise between pre-pubescent (9–10 y), pubescent (14–15 y), and post-pubescent (20–24 y) healthy, untrained females (n = 13/group). The maturation of the participants was confirmed by the hand bone age. All participants performed two bouts of 30 sub-maximal eccentric contractions (EC1, EC2) using a dumbbell set at 60% of pre-exercise maximal voluntary isometric elbow flexion strength at 90°. Changes in maximal voluntary concentric contraction (MVC) torque, muscle soreness (SOR), plasma creatine kinase activity, proprioception (position sense, joint reaction angle) and arterial stiffness (carotid-femoral pulse-wave velocity: cfPWV) before to 5 days after EC1 and EC2 were compared among groups by a mixed-design two-way ANOVA. Pre-exercise MVC torque and cfPWV were smaller (P < 0.05) for the pre-pubescent (MVC: 10.0 ± 0.9 Nm, cfPWV: 903 ± 60 cm/s) and the pubescent (14.3 ± 1.1 Nm, 967 ± 61 cm/s) than the post-pubescent (19.1 ± 1.4 Nm, 1,103 ± 73 cm/s). Changes in all variables after EC1 were smaller (P < 0.05) for the pre-pubescent (e.g., MVC at 1 d post-exercise: −10 ± 6%, peak SOR: 5 ± 2 mm) than the pubescent (−15 ± 9%, 12 ± 6 mm) and the post-pubescent (−25 ± 7%, 19 ± 13 mm). After EC2, changes in all variables were smaller (P < 0.05) than those after EC1 for all groups (e.g., MVC at 1 d post-exercise, pre-pubescent: −4 ± 6%, pubescent: −9 ± 4%, post-pubescent: −14 ± 5%; peak SOR: 3 ± 2, 7 ± 3, 11 ± 6 mm), but the magnitude of the repeated bout effect was not different (P > 0.05) among the groups. These results show that the extents of muscle damage, and proprioception and arterial stiffness changes after eccentric exercise are greater at later stages of maturation, but the repeated bout effect is not affected by maturation.

The influence of combat simulation exercises on indirect markers of muscle damage in soldiers of the brazilian army

The influence of combat simulation exercises on indirect markers of muscle damage in soldiers of the brazilian army

Low-intensity elbow flexion eccentric contractions attenuate maximal eccentric exercise-induced muscle damage of the contralateral arm

ObjectivesThe magnitude of muscle damage induced by maximal eccentric contractions (MaxEC) of the elbow flexors (EF) is reduced when it is preceded by low-intensity (10% of maximal voluntary isometric contraction strength) eccentric contractions (10%EC) of the same muscle, or by MaxEC of the opposite EF. This study investigated whether 10%EC would reduce the magnitude of muscle damage after MaxEC performed by the opposite arm. DesignComparison among 6 groups for changes in indirect markers of muscle damage. MethodYoung (21.0±1.8years) untrained men were assigned to five experimental groups (n=13/group) that performed 30, 10%EC followed by 30 MaxEC of the other arm performed at either 1 (1d), 2 (2d), 7 (1wk), 14 (2wk) or 21days (3wk) later, and one control group that performed 30 MaxEC without 10%EC (n=13). Changes in several indirect markers of muscle damage after MaxEC were compared among the groups by mixed-design two-way ANOVAs. ResultsNo significant changes in maximal voluntary concentric contraction torque, plasma creatine kinase activity and muscle soreness were evident after 10%EC. Changes in these variables after MaxEC were smaller (p<0.05) for the 1d, 2d and 1wk groups than control group, without significant differences between the 1d, 2d and 1wk groups. No significance differences in the changes were evident among the 2wk, 3wk and control groups, except for muscle soreness showing smaller (p<0.05) increases for the 2wk and 3wk groups than control group. ConclusionsThese results showed that 10%EC conferred muscle damage protection to the contralateral arm that performed MaxEC.

Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review.

Amino acids and more precisely, branched-chain amino acids (BCAAs), are usually consumed as nutritional supplements by many athletes and people involved in regular and moderate physical activities regardless of their practice level. BCAAs have been initially shown to increase muscle mass and have also been implicated in the limitation of structural and metabolic alterations associated with exercise damage. This systematic review provides a comprehensive analysis of the literature regarding the beneficial effects of BCAAs supplementation within the context of exercise-induced muscle damage or muscle injury. The potential benefit of a BCAAs supplementation was also analyzed according to the supplementation strategy—amount of BCAAs, frequency and duration of the supplementation—and the extent of muscle damage. The review protocol was registered prospectively with Prospective Register for Systematic Reviews (registration number CRD42017073006) and followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Literature search was performed from the date of commencement until August 2017 using four online databases (Medline, Cochrane library, Web of science and ScienceDirect). Original research articles: (i) written in English; (ii) describing experiments performed in Humans who received at least one oral BCAAs supplementation composed of leucine, isoleucine and valine mixture only as a nutritional strategy and (iii) reporting a follow-up of at least one day after exercise-induced muscle damage, were included in the systematic review analysis. Quality assessment was undertaken independently using the Quality Criteria Checklist for Primary Research. Changes in indirect markers of muscle damage were considered as primary outcome measures. Secondary outcome measures were the extent of change in indirect markers of muscle damage. In total, 11 studies were included in the analysis. A high heterogeneity was found regarding the different outcomes of these studies. The risk of bias was moderate considering the quality ratings were positive for six and neutral for three. Although a small number of studies were included, BCAAs supplementation can be efficacious on outcomes of exercise-induced muscle damage, as long as the extent of muscle damage was low-to-moderate, the supplementation strategy combined a high daily BCAAs intake (>200 mg kg−1 day−1) for a long period of time (>10 days); it was especially effective if taken prior to the damaging exercise.

Preconditioning by light-load eccentric exercise is equally effective as low-level laser therapy in attenuating exercise-induced muscle damage in collegiate men.

Background/objectivePrevious studies have already reported an independent effect of light-load eccentric exercise (10% eccentric exercise contraction [EEC]) and low-level laser therapy (LLLT) as a protective measure against more strenuous eccentric exercise. However, the difference between these two interventions is largely unknown. Therefore, the present study aimed to compare the preconditioning effect of 10% EEC vs. LLLT on subjective, physiological, and biochemical markers of muscle damage in elbow flexors in collegiate men.MethodsAll 36 enrolled subjects were randomly assigned to either 10% EEC or LLLT group. Subjects in 10% EEC group performed 30 repetitions of an eccentric exercise with 10% maximal voluntary contraction strength 2 days prior to maximal eccentric exercise bout, whereas subjects in LLLT group were given LLLT. All the indirect markers of muscle damage were measured pre-exercise and at 24, 48, and 72 hours after the exercise-induced muscle damage protocol.ResultsThe muscle soreness was reduced in both groups (p = 0.024); however, soreness was attenuated more in LLLT group at 48 hours (33.5 vs. 42.7, p = 0.004). There was no significant difference between the effect of 10% EEC and LLLT groups on other markers of muscle damage like a maximum voluntary isometric contraction (p = 0.47), range of motion (p = 0.16), upper arm circumference (p = 0.70), creatine kinase (p = 0.42), and lactate dehydrogenase (p = 0.08). Within-group analysis showed both interventions provided similar protection over time.ConclusionThis study indicated that light-load eccentric exercise confers similar protective effect against subsequent maximal eccentric exercise as LLLT. Both the treatments could be used reciprocally based on the patient preference, costs, and feasibility of the equipment.

Muscle Damage and Muscle Activity Induced by Strength Training Super-Sets in Physically Active Men.

Brentano, MA, Umpierre, D, Santos, LP, Lopes, AL, Radaelli, R, Pinto, RS, and Kruel, LFM. Muscle damage and muscle activity induced by strength training super-sets in physically active men. J Strength Cond Res 31(7): 1847-1858, 2017-In strength training, muscle activity is often analyzed by surface electromyography (EMG) and muscle damage through indirect markers, such as plasma concentrations of creatine kinase (CK) after exercise. However, there is little information about the influence of the strength exercises order on these parameters. The purpose of this study is to analyze the effect of strength exercises order (super-sets) in muscle activity and indirect markers of muscle damage. Twenty men were randomly assigned to one of the strength training sessions (TS). Each TS (5 sets × 8-10 repetition maximum) consisted of 2 exercises for the knee extensor muscles and 2 exercises for the horizontal shoulder flexors performed in a different order: exercises for the same muscle group grouped (grouped exercises [GE]: n = 10; 26.6 ± 3.4 years; 17.4 ± 3.4 body fat) or separated (separated exercises [SE]: n = 10; 24.9 ± 2.6 years; 15.4 ± 5.9 body fat). Muscle activity was analyzed by surface EMG (vastus lateralis [VL], vastus medialis [VM], rectus femoris [RF], pectoralis major [PM], and anterior deltoid [AD]), and the main indirect marker of muscle damage was the CK, evaluated immediately before and after the first 5 days of each TS. There was a higher EMG activity of GE in the RF (GE: 88.4% × SE: 73.6%) and AD (GE: 176.4% × SE: 100.0%), in addition to greater concentration of CK (GE: 632.4% × SE: 330.5%) after exercise. Our findings suggest that, in physically active men, implementing super-sets with GE promotes greater muscle effort and muscle damage, wherein 5 days are not enough to recover the trained muscle groups.

The repeated bout effect of traditional resistance exercises on running performance across 3 bouts.

This study investigated the repeated bout effect of 3 typical lower body resistance-training sessions on maximal and submaximal effort running performance. Twelve resistance-untrained men (age, 24 ± 4 years; height, 1.81 ± 0.10 m; body mass, 79.3 ± 10.9 kg; peak oxygen uptake, 48.2 ± 6.5 mL·kg-1·min-1; 6-repetition maximum squat, 71.7 ± 12.2 kg) undertook 3 bouts of resistance-training sessions at 6-repetitions maximum. Countermovement jump (CMJ), lower-body range of motion (ROM), muscle soreness, and creatine kinase (CK) were examined prior to and immediately, 24 h (T24), and 48 h (T48) after each resistance-training bout. Submaximal (i.e., below anaerobic threshold (AT)) and maximal (i.e., above AT) running performances were also conducted at T24 and T48. Most indirect muscle damage markers (i.e., CMJ, ROM, and muscle soreness) and submaximal running performance were significantly improved (P < 0.05; 1.9%) following the third resistance-training bout compared with the second bout. Whilst maximal running performance was also improved following the third bout (P < 0.05; 9.8%) compared with other bouts, the measures were still reduced by 12%-20% versus baseline. However, the increase in CK was attenuated following the second bout (P < 0.05) with no further protection following the third bout (P > 0.05). In conclusion, the initial bout induced the greatest change in CK; however, at least 2 bouts were required to produce protective effects on other indirect muscle damage markers and submaximal running performance measures. This suggests that submaximal running sessions should be avoided for at least 48 h after resistance training until the third bout, although a greater recovery period may be required for maximal running sessions.

Effects of lymphatic drainage and cryotherapy on indirect markers of muscle damage.

Muscle enzymes are cleared from the extracellular space by the lymphatic system, while smaller proteins enter the bloodstream directly. We investigated if manual lymphatic drainage (MLD), local cryotherapy (CRY), and rest (RST) differently affect the time course of creatine kinase (CK, 84 kDa) and heart-type fatty acid binding protein (h-FABP, 15 kDa) in the blood. Randomized controlled trial. After 4x20 unilateral, eccentric accentuated knee extensions (with one-third of the maximal isometric force) 30 sports students randomly received either a 30 min MLD, CRY or they rested (RST) for the same amount of time. CK, h-FABP, neutrophil granulocytes, and the perceived muscle soreness were assessed before, immediately after, and 1 hour, 4 hours, and 24 hours after the exercise. All measures increased significantly (P<0.001) after the protocol indicating that muscle damage was induced. However, the responses did not differ between the treatments. Large and small damage markers were not affected differently by MLD, CRY, or RST, when applied for 30 min and no beneficial effects on inflammation or muscle soreness could be found for MLD and CRY when compared to RST. This information is particularly important for those sports physicians and conditioning specialists who use biochemical muscle damage markers to adjust the training load and volume of athletes.

Effect of tendon vibration during wide-pulse neuromuscular electrical stimulation (NMES) on the decline and recovery of muscle force

BackgroundNeuromuscular electrical stimulation (NMES) is commonly used to activate skeletal muscles and reverse muscle atrophy in clinical populations. Clinical recommendations for NMES suggest the use of short pulse widths (100–200 μs) and low-to-moderate pulse frequencies (30–50 Hz). However, this type of NMES causes rapid muscle fatigue due to the (non-physiological) high stimulation intensities and non-orderly recruitment of motor units. The use of both wide pulse widths (1000 μs) and tendon vibration might optimize motor unit activation through spinal reflex pathways and thus delay the onset of muscle fatigue, increasing muscle force and mass. Thus, the objective of this study was to examine the acute effects of patellar tendon vibration superimposed onto wide-pulse width (1000 μs) knee extensor electrical stimulation (NMES, 30 Hz) on peak muscle force, total impulse before “muscle fatigue”, and the post-exercise recovery of muscle function.MethodsTendon vibration (Vib), NMES (STIM) or NMES superimposed onto vibration (STIM + Vib) were applied in separate sessions to 16 healthy adults. Total torque-time integral (TTI), maximal voluntary contraction torque (MVIC) and indirect measures of muscle damage were tested before, immediately after, 1 h and 48 h after each stimulus.ResultsTTI increased (145.0 ± 127.7%) in STIM only for “positive responders” to the tendon vibration (8/16 subjects), but decreased in “negative responders” (−43.5 ± 25.7%). MVIC (−8.7%) and rectus femoris electromyography (RF EMG) (−16.7%) decreased after STIM (group effect) for at least 1 h, but not after STIM + Vib. No changes were detected in indirect markers of muscle damage in any condition.ConclusionsTendon vibration superimposed onto wide-pulse width NMES increased TTI only in 8 of 16 subjects, but reduced voluntary force loss (fatigue) ubiquitously. Negative responders to tendon vibration may derive greater benefit from wide-pulse width NMES alone.

The Potential Of Omega 3 Supplementation To Reduce Muscle-inflammation After Muscle-damaging Exercise

Muscle inflammation which follows exercise-induced muscle damage (EIMD) relates to strength loss, muscle-soreness and impaired recovery (Lynn and Morgan, 1994). It remains unclear whether omega-3 fatty acids (O-3) supplementation blunts the exercise-induced inflammation associated with EIMD. PURPOSE: Following supplementation with O-3, indirect markers of muscle damage were examined after EIMD to determine if supplementation had any beneficial effect in reducing muscle inflammation. METHODS: Eight healthy, recreationally active caucasian males (28.13 ± 3.4 yrs) were randomly allocated to a supplementation group (SUP, n = 4) to receive 2.85g/day O-3 supplementation or a placebo group (CON, n = 4) for three weeks. After three-weeks, participants performed a bout of EIMD, which consisted of performing 10 sets of 15 repetitions of leg extension on a Rating of Perceived Exertion (RPE) of 7/10 (Borg, 1982). Creatine Kinase (CK) from venous blood samples, isometric right-leg strength, squat-jump test and perceived soreness were determined, as indirect markers of muscle-damage at Baseline, immediately after EIMD (POST) and 48 hours after EIMD to coincide with the delayed muscle inflammatory response. RESULTS: No differences were found between Baseline and POST. There was a trend for smaller increase of CK levels (pre vs 48-h post EIMD) on the SUP group (38.8% increase) compared with the CON group (105.6% increase; P = 0.051). There was no significant effect (baseline vs. 48-h post EIMD) on muscle strength between SUP and CON group (P > 0.05), however, CON showed a larger decrease in strength compared to SUP (>6.3% vs SUP). No differences in jump height were found between SUP and CON (P > 0.05). There was no significant difference in muscle soreness at 48-h post EIMD between SUP and CON group (P = 0.171). CONCLUSION: Three weeks of O-3 supplementation decreased exercise-induced muscle inflammation after eccentric exercise. The encouraging results from this pilot study have led to designing further work related to this topic. The lack of statistical significance may be adduced to the limitations of the study design. Supplementation with O-3 can be beneficial in sedentary individuals re-starting physical activity and in athletes undergoing heavy exercise regimes, decreasing the exercise related muscle inflammation.

Periodization Training Focused on Technical-Tactical Ability in Young Soccer Players Positively Affects Biochemical Markers and Game Performance.

Aquino, RLQT, Cruz Gonçalves, LG, Palucci Vieira, LH, Oliveira, LP, Alves, GF, Pereira Santiago, PR, and Puggina, EF. Periodization training focused on technical-tactical ability in young soccer players positively affects biochemical markers and game performance. J Strength Cond Res 30(10): 2723-2732, 2016-The aim of this study was to investigate the effects of 22 weeks of periodized training, with an emphasis on technical-tactical ability, on indirect markers of muscle damage, and the on-field performance of young soccer players. Fifteen players (age 15.4 ± 0.2 years, height 172.8 ± 3.6 cm; body mass 61.9 ± 2.9 kg; % fat 11.7 ± 1.6; V[Combining Dot Above]O2max 48.67 ± 3.24 ml·kg·min) underwent 4 stages of evaluation: prepreparatory stage-T0; postpreparatory stage-T1; postcompetitive stage I-T2 and; postcompetitive stage II-T3. The plasmatic activity of creatine kinase (CK) and lactate dehydrogenase (LDH) were evaluated, as well as the on-field performance (movement patterns, tactical variables). Regarding the plasmatic activity of CK and LDH, there was a significant reduction (p ≤ 0.05) throughout the periodization training (T0: 350 U·L; T3: 150 U·L). Significant increases were observed (p ≤ 0.05) in the intensity of the game, high-intensity activities (HIA) (T0: 22%; T3: 27%), maximum speed (T0: 30 km·h; T3: 34 km·h) and tactical performance, team surface area (T0: 515 m; T3: 683 m), and spread (T0: 130 m; T3: 148 m). In addition, we found significant inverse correlations between the percentage variation of T0 to T3 in CK and LDH activities with percentage variation in high-intensity running (r = -0.85; p ≤ 0.05 and r = -0.84; p < 0.01, respectively) and HIA (r = -0.71 and r = -0.70; p ≤ 0.05, respectively) during the matches. We concluded that there was reduced activity in biochemical markers related to muscle damage, as well as increases in-game high-intensity performance and the tactical performance of the study participants. Furthermore, players who showed greater reduction in plasma activity of CK and LDH also obtained greater increases in-game high-intensity performance along the periodization. These results may contribute to the expansion and future consolidation of the knowledge of coaches and sport scientists to develop effective methodologies for training in soccer.

MON-LB285: Effects of HMB Supplementation on Indirect Markers of Muscle Damage in Novice Resistance Trained Males

MON-LB285: Effects of HMB Supplementation on Indirect Markers of Muscle Damage in Novice Resistance Trained Males

A single dose of histamine-receptor antagonists before downhill running alters markers of muscle damage and delayed-onset muscle soreness.

Histamine contributes to elevations in skeletal muscle blood flow following exercise, which raises the possibility that histamine is an important mediator of the inflammatory response to exercise. We examined the influence of antihistamines on postexercise blood flow, inflammation, muscle damage, and delayed-onset muscle soreness (DOMS) in a model of moderate exercise-induced muscle damage. Subjects consumed either a combination of fexofenadine and ranitidine (blockade, n = 12) or nothing (control, n = 12) before 45 min of downhill running (-10% grade). Blood flow to the leg was measured before and throughout 120 min of exercise recovery. Markers of inflammation, muscle damage, and DOMS were obtained before and at 0, 6, 12, 24, 48, and 72 h postexercise. At 60 min postexercise, blood flow was reduced ~29% with blockade compared with control (P < 0.05). Markers of inflammation were elevated after exercise (TNF-ɑ, IL-6), but did not differ between control and blockade. Creatine kinase concentrations peaked 12 h after exercise, and the overall response was greater with blockade (18.3 ± 3.2 kU·l-1·h-1) compared with control (11.6 ± 2.0 kU·l-1·h-1; P < 0.05). Reductions in muscle strength in control (-19.3 ± 4.3% at 24 h) were greater than blockade (-7.8 ± 4.8%; P < 0.05) and corresponded with greater perceptions of pain/discomfort in control compared with blockade. In conclusion, histamine-receptor blockade reduced postexercise blood flow, had no effect on the pattern of inflammatory markers, increased serum creatine kinase concentrations, attenuated muscle strength loss, and reduced pain perception following muscle-damaging exercise.NEW & NOTEWORTHY Histamine appears to be intimately involved with skeletal muscle during and following exercise. Blocking histamine's actions during muscle-damaging exercise, via common over-the-counter antihistamines, resulted in increased serum creatine kinase, an indirect marker of muscle damage. Paradoxically, blocking histamine's actions attenuated muscle strength loss and reduced perceptions of muscle pain for 72 h following muscle-damaging exercise. These results indicate that exercise-induced histamine release may have a broad impact on protecting muscle from exercise-induced damage.

Time-course of changes in indirect markers of muscle damage responses following a 130-km cycling race

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n3p322 The purpose of the present investigation was to identify the effects of a 130-km cycling race on indices of biochemical indirect markers of muscle damage and muscle soreness responses during a 72-hour recovery period. Fifteen endurance-trained male cyclists which were competing for more than 2 years and were involved in systematic training at least of 3 days/wk underwent a collection of indirect biochemical markers of muscle damage (CK, LDH, Myo) and delayed onset of muscle soreness (DOMS), at five different moments of data collection: before (PRE) and immediately after (POST) a 130-km cycling race, and 24, 48, 72 hours following the cycling race. CK and LDH plasma concentrations significantly increased POST-race (p &lt; 0.001) and remained high throughout the 72 hour recover period (CK: p &lt; 0.05; LDH: p &lt; 0.001). Myo increased significantly POST-race (p &lt; 0.001) and returned to the PRE-race values 24 hours thereafter (p &lt; 0.05). DOMS increased significantly POST-race (p &lt; 0.001) and returned to the PRE-race values at 48 hours after (p &gt; 0.05). A 130-km cycling race has a noteworty effect on indices of biochemical indirect markers of muscle damage and muscle soreness responses, indicating that 72 hour recovery period do not seems to be enough for long-distance cyclist, and reinforce the propositions of scientific literature about the need of a sufficient recovery period for cycling endurance athletes.

Effects of far infrared rays emitting clothing on recovery after an intense plyometric exercise bout applied to elite soccer players: a randomized double-blind placebo-controlled trial.

The aim was to investigate the effects of far infrared (FIR) ray emitting clothes on indirect markers of exercise-induced muscle damage and physical performance recovery after a plyometric bout applied to soccer players. Twenty-one male players (18.9±0.6 years; 70.8±5.01 kg; 178.3±0.06 cm) performed 100 drop-jumps. Six hours after the bout, athletes put on FIR clothes (FIR) (density of 225 g·m-2, 88% far infrared rays emitting polyamide 66 Emana yarn (PA66) fibre, 12% Spandex, emissivity of 0.88 and power emitted of 341 W/m2µm at 37°C in the 5-20 µm wavelength range, patent WO 2009/077834 A2) (N = 10) or placebo clothes (PLA) (N = 11). Mid-thigh circumferences, creatine kinase (CK), and delayed-onset muscle soreness (DOMS) were assessed before, immediately after and 24, 48, and 72 h after the bout. Squat (SJ) and countermovement jump (CMJ) heights were measured before and at 24, 48, and 72 h after, while 1RM leg press (maximum strength) was measured before and at 72 h after the plyometrics. No differences between groups were found in mid-thigh circumferences, SJ, CMJ or 1RM. CK increased significantly 24 h after the plyometrics in comparison to before (p < 0.05) in both groups. PLA showed significant DOMS increases at 24, 48, and 72 h, while FIR showed significant increases at 24 and 48 h (p < 0.05). DOMS effect sizes were greater in FIR (moderate at 48 h, ES = 0.737 and large at 72 h, ES = 0.844), suggesting that FIR clothes may reduce perceived DOMS after an intense plyometric session performed by soccer players.