Douleurs musculaires post-effort

DOMS (Delayed Onset Muscle Soreness) occurs frequently in sport. DOMS usually develops 12-48 hours after intensive and/or unusual eccentric muscle action. They can be associated with decreased proprioception and range of motion, as well as maximal strength. DOMS disappears 2–10 days before complete functional recovery. Inflammation appears to be the most common explanation. DOMS should not be considered as an indicator of muscle damage but, rather, a sign of the regenerative process, which is well known to contribute to be increase muscle mass. If some treatments are well known to attenuate DOMS, none has been demonstrated to accelerate either structural or functional recovery.     

Rehabilitation of muscle after injury – the role of anti‐inflammatory drugs

Non‐steroidal anti‐inflammatory drugs (NSAIDs) are widely consumed among athletes worldwide in relation to muscle injury and soreness. This review aims to provide an overview of studies investigating their effects on skeletal muscle, in particular the repair processes in injured muscle. Muscle injury occurs in diverse situations and the nature of muscle injuries varies significantly, complicating extrapolations between experimental models and “real life.” Classical muscle strain injuries occur at the interphase between the muscle fibers and connective tissue, most often in the myotendinuous junction, whereas contusion or overload injury can damage both myofibers and intramuscular connective tissue. The role of NSAIDs in muscle repair is complicated by differences in injury models used, variables evaluated, and time point(s) selected for evaluations. While the temporal pattern of the influence of NSAIDs on muscle repair is difficult to settle on, it appears that a potential beneficial effect of NSAIDs in the early phase after injury is not maintained in the long term, or is even negated by a long‐term repair deficit. At the cellular level, evidence exists for a negative influence of NSAIDs on the muscle stem cell population (satellite cells). At a structural level, it is known that muscle connective tissue undergoes significant remodeling during muscle regeneration, but the potential of NSAID exposure to alter this response in humans needs investigation.     

推拿对DOMS作用机理的研究概况

延迟性肌肉酸痛是困扰运动医学界多年的话题，人们至今没有找到它确切的发生机理，学术界推测其发生机理可能为肌肉微损伤、肌肉痉挛缺血及炎症反应等。推拿对延迟性肌肉酸痛有很好的疗效，本文从外周机制、脊髓水平、中枢水平及心理调节四方面来论述推拿对延迟性肌肉的疗效机制。     

中药消除运动性疲劳临床研究之一——抗肌肉疲劳中药对女子划船运动员肌肉酸痛症的临床疗效观察

目的:观察自制抗疲劳中药"疲王颗粒"对女子划船运动员延迟性肌肉酸痛症(DOMS)的治疗效果。方法:60名女子划船运动员,随机分为实验组和对照组。在冬训大运动量、大强度训练周期中,运动员被诊断为DOMS,采用双盲法分别给予自制疲王颗粒和安慰剂,连续服药7天。在实验开始前1天,实验第3、7天(结束时)分别于肘静脉取血,检测CK、BUN和血常规。在实验开始前1天,实验第2、3、5、7天(结束时),采用VAS10分评分法,对肌肉酸痛进行问卷调查和评分。结果:实验组第5天开始VAS评分与第2、3天相比显著降低(P<0.05);实验第7天,两组VAS评分均较本组之前各时间点显著降低(P<0.05)。实验组CK第7天分别较实验前和第3天显著下降(P<0.05);对照组第7天较第3天显著降低(P<0.05)。实验组WBC第3天较实验前显著降低(P<0.05)。结果提示,自制抗疲劳中药"疲王颗粒"对女子划船运动员训练后引起的运动性肌肉疲劳酸痛症的消除有一定效果。     

Recovery pattern of motor reflex after a single bout of neuromuscular electrical stimulation session

We aimed at determining the recovery pattern of neural properties of soleus muscle after a single bout of neuromuscular electrical stimulation (NMES) session. Thirteen subjects performed an NMES exercise (75 Hz, 40 contractions, 6.25 s per contraction). Maximal voluntary contraction (MVC), H‐reflex at rest and during voluntary contraction fixed at 60% of MVC (respectively, H_max and H_sup) and volitional (V) wave were measured before and during the recovery period following this exercise [i.e., immediately after, 2 h (H2), 2 days (D2) and 7 days (D7)]. MVC exhibited an immediate and a delayed declines at 2 days (respectively, ?29.8±4.6%, P<0.001; ?13.0±3.4%, P<0.05). Likewise, V/M_sup was decreased immediately and 2 days after NMES session (respectively, ?43.3±11.6%, P<0.05; 35.3±6.6%, P<0.05). The delayed decrements in MVC and V‐wave occurred concomitantly with muscle soreness peak (P<0.001). It could be concluded that motor command alterations after an NMES resistance session contributed to the immediate and also to the delayed decreases in MVC without affecting resting and active H‐reflex excitability. These results suggested that spinal circuitry function of larger motoneurons was inhibited by NMES (as indicated by the depressed V‐wave responses) contrary to the smaller one (indicated by the unchanged H‐reflex responses).     

Effects of number of eccentric muscle actions on first and second bouts of eccentric exercise of the elbow flexors

This study compared changes in indirect markers of muscle damage following eccentric exercise of the elbow flexors among the exercises consisting of different number of eccentric actions. Sixty male athletes were placed into one of the six groups (n=10 per group) based on the number of eccentric actions for the first (ECC1) and second exercise bouts (ECC2). Single bout groups (30, 50, and 70) performed ECC1 only, and repeated bout groups (30-30, 50-50, and 70-70) performed ECC2 3 days after ECC1. Another 10 male athletes performed different number of eccentric actions for ECC1 (30) and ECC2 (70) separated by 3 days (30-70). Changes in maximal isometric strength (MVC), range of motion (ROM), upper arm circumference (CIR), serum creatine kinase activity, myoglobin, and nitric oxide concentrations and muscle soreness for 10 days following ECC1 were compared among groups by two-way repeated measures ANOVA. Changes in MVC, ROM, and CIR following ECC1 were significantly (P<0.05) smaller for the groups that performed 30 eccentric actions compared with other groups. No significant differences between 30 and 30-30, 50 and 50-50, and 70 and 70-70 were evident for the changes in the measures for 10 days following ECC1 except for the acute decreases in MVC and ROM immediately after ECC2 for the repeated bout groups. The 30-30 and 30-70 groups showed similar changes in all criterion measures. It is concluded that recovery from eccentric exercise is not retarded by the second bout of eccentric exercise regardless of the number of eccentric actions.     

Pain-related fear predicts reduced spinal motion following experimental back injury

The current study examined the prospective relationship between pain-related fear and altered motor behavior, as well as perceived interference, among 51 healthy participants following induction of delayed-onset muscle soreness (DOMS) to the trunk extensor muscles. Healthy participants without history of back pain completed standardized reaches to high and low targets at self-paced and rapid speeds before and after induction of acute low back pain using a DOMS paradigm. Pain-related fear was assessed prior to DOMS induction. Three-dimensional joint motions of the thoracic spine, lumbar spine, and hip were recorded using an electromagnetic tracking device. DOMS-induced differences between high- and low-fear participants were observed for lumbar spine flexion, but not for thoracic or hip flexion. Pain-related fear scores were not predictive of lumbar flexion during baseline, but predicted reduced lumbar flexion during self- and fast-paced trials to low target locations once DOMS was induced. Pain-related fear was likewise predictive of perceived interference in life activities following DOMS induction. The findings suggest that initially pain-free individuals with high pain-related fear adopt avoidant spinal strategies during common reaching movements shortly after injury is sustained, which may comprise a risk factor for future pain and disability.     

The effects of Lyprinol(®) on delayed onset muscle soreness and muscle damage in well trained athletes: a double-blind randomised controlled trial

Objectives

The aim of the study was to determine if Lyprinol^® is effective in reducing pain, indicators of inflammation and muscle damage, and in turn improving performance in well trained athletes suffering from delayed onset muscle soreness (DOMS).

Design

A double blind randomised placebo controlled trial.

Setting

Twenty well trained male volunteers, matched by VO_{2 max} were randomly assigned to consume 200 mg of Lyprinol^® or an indistinguishable placebo daily for 8 weeks prior to a downhill treadmill running episode designed to induce DOMS.

Main outcome measures

Performance measures (Kin-Com, counter movement and squat jump), pain assessments (visual analogue scale, algometer) and blood analyses (Interleukin-1, Interleukin-6, Interleukin-10, tumour necrosis factor-α, C-reactive protein, myoglobin, creatine kinase) were assessed at 7 time points over 5 days (pre, post, 4, 24, 48, 72 and 96 h after the downhill run).

Results

No statistically significant differences were identified in any parameters between the active and placebo groups at any time point.

Conclusion

After 2 months ingestion of Lyprinol^® at the currently recommended dosage (200 mg/day) and a demanding eccentric exercise intervention, Lyprinol^® did not convincingly affect DOMS and indicators of muscle damage.     

Magnetic resonance imaging of acute “wiiitis” of the upper extremity

We present the first reported case of acute “wiiitis”, documented clinically and by imaging, of the upper extremity, caused by prolonged participation in a physically interactive virtual video-game. Unenhanced magnetic resonance imaging (MRI) demonstrated marked T2-weighted signal abnormality within several muscles of the shoulder and upper arm, without evidence of macroscopic partial- or full-thickness tearing of the muscle or of intramuscular hematoma.