Jean-Louis Croisier

An isokinetic eccentric programme for the management of chronic lateral epicondylar tendinopathy

Background: Lateral epicondylitis represents a frequent overuse injury. In spite of many conservative treatment procedures, prolonged symptoms and relapse are frequently observed. Objective: To compare the outcome of patients performing an isokinetic eccentric training with that of age-, gender-, activity-matched patients receiving a non-strengthening classical rehabilitation. Methods: Ninety-two patients with unilateral chronic lateral epicondylar tendinopathy (mean duration of symptoms 8±3 months) were assigned either to a control group (n = 46) or to an eccentrically trained group (n = 46). The control group underwent a passive standardised rehabilitation programme that excluded strengthening exercises. In addition to this programme, the trained group also performed eccentric exercises based on the repetitive lengthening of the active musculo-tendinous unit. The latter exercises started with submaximal contraction intensity and slow speed movement. Modalities were progressively intensified (increase in intensity contraction and speed movement) over a long priod of treatment. Programme effectiveness was assessed through pain score evaluation, a disability questionnaire, muscle strength measurement and ultrasonographic examination. Results: Compared to the non-strengthening control group, the following observations were made in the eccentrically trained group: (1) a significantly more marked reduction of pain intensity, mainly after one month of treatment; (2) an absence of strength deficit on the involved side through bilateral comparison for the forearm supinator and wrist extensor muscles; (3) an improvement of the tendon image as demonstrated by decreasing thickness and a recovered homogenous tendon structure; and (4) a more marked improvement in disability status during occupational, spare time and sports activities. Conclusion: These results highlight the relevance of implementing isokinetic adapted eccentric training in the management of chronic lateral epicondylar tendinopathy.

Effects of training on exercise-induced muscle damage and interleukin 6 production

To address the question of whether the increased plasma concentration of interleukin 6 (IL‐6) following strenuous muscular work could be related to exercise‐induced muscle damage, 5 moderately active male volunteers underwent two isokinetic exercise sessions in the eccentric mode, separated by a period of 3 weeks during which the subjects underwent five training sessions. Before training, exercise was followed by severe muscle pain (delayed‐onset muscle soreness; DOMS), and by significant increases in plasma IL‐6 level and serum myoglobin concentration (SMb) (P < 0.001). After training, postexercise DOMS and SMb values were significantly lower than those measured before training. There was no significant difference between plasma IL‐6 levels measured at the same time points before and after training. We conclude that the hypothetical relationship between exercise‐induced muscle damage and increased postexercise levels of circulating IL‐6 is not substantiated by the present results.

Pressure pain thresholds of tender point sites in patients with fibromyalgia and in healthy controls

Pressure pain threshold (PPT) is defined as the minimum force applied which induces pain. This measure has proven to be commonly useful in evaluating tenderness symptom. Our aim was to study the intra‐examiner reproducibility of PPT measurement, define cutoffs in normal groups, and compare these results with patients with fibromyalgia (FM). Fifty healthy females, 50 healthy males, and 20 patients with FM participated in the study. PPTs were assessed for 18 specific tender point sites by a dolorimeter. The intra‐individual coefficient of variation determined by a test—retestPPT measurement procedure with 3‐days interval reached, respectively, 17% and 13% in healthy females and males, versus 24% in patients with FM. PPTs were significantly lower in healthy females than in healthy males (p<0.01). Statistical analysis failed to show any differences between the dominant and nondominant side for both normal groups. PPTs were lower over all examined areas in patients with FM than those obtained in healthy females (p<0.000). Lower cutoff levels were calculated from normal values for all specific tender point sites. On average, 14 tender point sites in patients with FM were under the established lower cutoffs. In conclusion, pressure pain sensitivity was influenced by the anatomical localization of tender point and gender differences. Lowest PPTs were localized in trapezius, occiput, anterior cervical, and second rib. The reduction of total tender point score in patients with FM averaged 60% comparatively with normal values. PPT reproducibility and discrimination between the two groups were optimal for the gluteal and knee sites.

Muscle performance in patients with fibromyalgia

OBJECTIVES To compare muscle performance in women with fibromyalgia and in healthy women. PATIENTS AND METHODS Sixteen women with fibromyalgia syndrome (FMS) and 85 healthy women who were physically inactive or engaged in recreational sports underwent measurements of four parameters: maximal concentric isokinetic muscle strength of the knee extensors and flexors in the dominant limb, isometric grip strength on a Colin dynamometer, muscle fatigue resistance during 30 maximal concentric isokinetic contractions of the dominant knee flexors and extensors at 180 degrees angular velocity, and static endurance during posture maintenance. RESULTS All muscle variables were decreased in the FMS patients as compared to the controls. The decreases were more marked during aerobic than during anaerobic exercise. Mean decreases were 39% (P<0.001) for muscle strength, 40% (P<0.0001) for fatigue resistance, and 81% (P<0.0001) for static endurance. Pain during exercise as evaluated using a visual analog scale was more marked in the FMS patients. CONCLUSION This study of the three pathways supplying energy to muscle confirms that muscle function is globally impaired in FMS patients. The results suggest that the impairment predominates on aerobic processes.

Factors Correlated With Volleyball Spike Velocity

Background Spike effectiveness represents a determining element in volleyball. To compete at a high level, the player must, in particular, produce a spike characterized by a high ball velocity. Hypothesis Some muscular and physical features could influence ball velocity during the volleyball spike. Study Design Descriptive laboratory study. Methods A total of 19 male volleyball players from the 2 highest Belgian national divisions underwent an isokinetic assessment of the dominant shoulder and elbow. Ball velocity performance (radar gun) during a spike test, morphological feature, and jump capacity (ergo jump) of the player were measured. We tested the relationship between the isokinetic parameters or physical features and field performances represented by spike velocity. We also compared first-division and second-division player data. Results Spike velocity correlated significantly with strength performance of the dominant shoulder (internal rotators) and of the dominant elbow (flexors and extensors) in the concentric mode. Negative correlations were established with the concentric external rotator on internal rotator ratio at 400 deg/s and with the mixed ratio (external rotator at 60 deg/s in the eccentric mode on internal rotator at 240 deg/s in the concentric mode). Positive correlations appeared with both the volleyball players’ jump capacity and body mass index. First-division players differed from second-division players by higher ball velocity and increased jump capacity. Conclusion Some specific strength and physical characteristics correlated significantly with spike performance in high-level volleyball practice. Clinical Relevance Our results could provide useful information for training management and propose some reflections on injury prevention.

Scapular positioning in athlete's shoulder : particularities, clinical measurements and implications.

Despite the essential role played by the scapula in shoulder function, current concepts in shoulder training and treatment regularly neglect its contribution. The ‘scapular dyskinesis’ is an alteration of the normal scapular kinematics as part of scapulohumeral rhythm, which has been shown to be a nonspecific response to a host of proximal and distal shoulder injuries. The dyskinesis can react in many ways with shoulder motion and function to increase the dysfunction. Thoracic kyphosis, acromio-clavicular joint disorders, subacromial or internal impingement, instability or labral pathology can alter scapular kinematics. Indeed, alteration of scapular stabilizing muscle activation, inflexibility of the muscles and capsule-ligamentous complex around the shoulder may affect the resting position and motion of the scapula. Given the interest in the scapular positioning and patterns of motion, this article aims to give a detailed overview of the literature focusing on the role of the scapula within the shoulder complex through the sports context. Such an examination of the role of the scapula requires the description of the normal pattern of scapula motion during shoulder movement; this also implies the study of possible scapular adaptations with sports practice and scapular dyskinesis concomitant to fatigue, impingement and instability. Different methods of scapular positioning evaluation are gathered from the literature in order to offer to the therapist the possibility of detecting scapular asymmetries through clinical examinations. Furthermore, current concepts of rehabilitation dealing with relieving symptoms associated with inflexibility, weakness or activation imbalance of the muscles are described. Repeating clinical assessments throughout the rehabilitation process highlights improvements and allows the therapist to actualize rationally his or her intervention. The return to the field must be accompanied by a transitory phase, which is conducive to integrating new instructions during sports gestures. On the basis of the possible scapular disturbance entailed in sports practice, a preventive approach that could be incorporated into training management is encouraged.

Spatial Distribution of Blood Flow in Electrically Stimulated Human Muscle: A Positron Emission Tomography Study

Neuromuscular electrical stimulation (NMES) was studied with positron emission tomography (PET) and H215O in the quadriceps muscle of 11 men. The subjects were submitted to simultaneous bilateral isometric contraction (5 s)–rest (5 s) cycles for 12 min, with a workload corresponding to 5% of quadriceps maximal isometric voluntary torque (QMIVT) for one thigh (5%T) and 10% of QMIVT for the other (10%T). Scans were centered at the electrodes and tissue blood flow (TBF) was evaluated in square regions of interest (ROIs) (3.5 cm2) in the transverse section (TS) of both thighs. The mean TBF reached 8.9 mL min−1 100 g−1 in the TS of the 5%T and 11.5 mL min−1 100 g−1 in the TS of the 10%T (P > 0.05). A negative linear relationship was found for both thighs between the ROI–electrode distance and the TBF (P ≤ 0.009). The mean percentage of activated ROIs (TBF > 5 mL min−1 100 g−1) was lower in the 5%T than in the 10%T (50.6% vs. 62.2%; P = 0.017). With NMES, the pattern of spatial recruitment appears linked to electrode proximity and is spatially extended. These results confirm the utility of combining NMES with voluntary exercise in the treatment of atrophied muscle.

Human Muscle Proteome Modifications after Acute or Repeated Eccentric Exercises

INTRODUCTION Delayed-onset muscle soreness (DOMS), a condition triggered by eccentric exercise, affects muscle cells at a biochemical level in a poorly understood fashion. The objective of the present study was to examine human muscle proteome modifications induced by strenuous eccentric exercises after a specific training aimed to prevent DOMS. METHODS Biopsy samples of the rectus femoris were obtained from healthy human volunteers in three successive conditions: 1) at rest, 2) 24 h after an injuring exercise protocol consisting of three series of 30 maximal contractions of the quadriceps on an isokinetic dynamometer, and 3) 24 h after a similar exercise bout preceded either by five eccentric training sessions or by no training. RESULTS Muscle damage was assessed before and 1 d after each maximal eccentric test by comparing three indirect markers: plasma activity of creatine kinase, muscle stiffness, and subjective pain intensity. Compared with the first eccentric test, those markers were reduced after the second test and further reduced if this second test followed the eccentric training, thus confirming the protective effect of such training. Muscle protein extracts were subjected to a two-dimensional difference gel electrophoresis proteomic analysis coupled with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry protein identification. Surprisingly, we observed that myosin heavy chains decreased after the first eccentric test and were reduced further with other contractile proteins after the second test. Furthermore, the expression of several glycolytic enzymes decreased only after the second test, which was preceded by a specific training. CONCLUSIONS These findings suggest that the eccentric training resulted in a switch to oxidative metabolism, which may be associated with protection from DOMS.

Isokinetic assessment of the shoulder rotators: a study of optimal test position

Background:  Isokinetic assessment of the shoulder rotator cuff is a common component of shoulder muscles assessment. Nevertheless, the extensive mobility of the shoulder poses great difficulty in finding a consensus protocol for evaluation.

Muscle fatigue experienced during maximal eccentric exercise is predictive of the plasma creatine kinase (CK) response

Unaccustomed eccentric exercise may cause skeletal muscle damage with an increase in plasma creatine kinase (CK) activity. Although the wide variability among individuals in CK response to standardized lengthening contractions has been well described, the reasons underlying this phenomenon have not yet been understood. Therefore, this study investigated a possible correlation of the changes in muscle damage indirect markers after an eccentric exercise with the decline in muscle performance during the exercise. Twenty‐seven healthy untrained male subjects performed three sets of 30 maximal isokinetic eccentric contractions of the knee extensors. The muscular work was recorded using an isokinetic dynamometer to assess muscle fatigue by means of various fatigue indices. Plasma CK activity, muscle soreness, and stiffness were measured before (pre) and one day after (post) exercise. The eccentric exercise bout induced significant changes of the three muscle damage indirect markers. Large inter‐subject variability was observed for all criteria measured. More interestingly, the log (CKpost/CKpre) and muscle stiffness appeared to be closely correlated with the relative work decrease (r = 0.84, r2 = 0.70 and r = 0.75, r2 = 0.56, respectively). This is the first study to propose that the muscle fatigue profile during maximal eccentric protocol could predict the magnitude of the symptoms associated with muscle damage in humans.