The exact cause of tennis elbow, a common condition, is still obscure. While the condition may well be entirely due to a local disorder at the elbow, the results of a study of 50 patients whose condition was resistant to 4 weeks of treatment directed to the elbow suggest that the underlying condition may have been (at least in these patients) a reflex localization of pain from radiculopathy at the cervical spine. Clinical, radiologic and electromyographic findings supported this suggestion. The pain was demonstrated to be muscular tenderness, which was maximal and specific at motor points. Treatment directed to the cervical spine appeared to give relief in the majority of patients. The more resistant the condition, the more severe were the radiologic and electromyographic findings in the cervical spine. (+info)
Effect of a selected amino acid mixture on the recovery from muscle fatigue during and after eccentric contraction exercise training.
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The effect of an amino acid mixture on the recovery from muscle fatigue after eccentric exercise (ECEX) training was examined in twenty-two male college students. The administration of 5.6 g of the amino acid mixture twice daily resulted faster recovery of muscle strength than that with a placebo. The oral administration of the amino acid mixture was proved to effective for muscle strength recovery after the eccentric exercise. (+info)
Muscular performance modeling of the upper limb in static postures.
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The purpose of the present paper is to describe and evaluate the polynomial models for predicting the muscular work capacity of the upper limb during sustained holding tasks. This research was concerned with the relationship between indicators of performance, i.e., specific posture or specific level of maximum voluntary contraction (MVC), and then modeling the functional data based on experimental results to estimate factors that may have an effect on task performance. To this end, we designed an experiment using 10 subjects in which each subject performed sustained isometric shoulder and elbow flexion endurance exercise under 27 conditions [3 shoulder angles (SA)x3 elbow angles (EA)x3 levels of %MVC]. Throughout all experiments, subjective perception of effort was assessed using the Borg scale, every 60, 30, and 10 s during the 20%, 40%, and 60% MVC tests, respectively. Proposal models were represented by three approaches: model A: estimation of endurance time (ET), with input variables such as SA, EA, and %MVC; model B: estimation of recommendation time (RT, the time during which the operator was able to maintain a position under the desired condition), with input variables such as SA, EA, %MVC, and required rate on the Borg scale; and model C: estimation of limit strength or %MVC, with input variables such as SA, EA, request limit time for work (LT), and required rate on the Borg scale. Statistical analysis indicated that the three proposal estimation models based on polynomial regression functions showed high significance (p<0.0001). The proposal models suggested and recommended the possibility of finding the best positions entailing the reduction and minimization of total muscular strain from manual material handling tasks in different work situations, with the consequent increase in work efficiency. (+info)
The objective diagnosis of early tennis elbow by magnetic resonance imaging.
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OBJECTIVE: To identify the salient magnetic resonance imaging (MRI) features of tennis elbow. An objective diagnosis is important when managing work-related incapacity due to ill-defined lateral arm pain. METHOD: Twenty-three symptomatic and 17 asymptomatic elbows in 20 patients with tennis elbow, no evidence of other pathology and no previous treatment were imaged using established MRI sequences. RESULTS: In the symptomatic elbows, the common extensor origin (CEO) showed signs of oedema in 23, thickening in 19, peri-tendon oedema in 3 and tears in 13 cases. More extensive abnormalities were demonstrated in only two elbows. Six out of 17 asymptomatic elbows also showed oedema in the CEO. CONCLUSIONS: The CEO is confirmed as the primary site of MRI changes in tennis elbow. Oedema was commonly found in asymptomatic elbows, necessitating the presence of thickening or tears in the CEO tendon to objectively diagnose tennis elbow on MRI. (+info)
Central and peripheral fatigue of human diaphragm and limb muscles assessed by twitch interpolation.
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1. This study used a sensitive modification of the twitch interpolation technique to compare the extent of voluntary neural drive to the diaphragm and the elbow flexors during fatigue. For the diaphragm both inspiratory and expulsive efforts were tested, and fatigue was induced by expulsive efforts which were either maximal voluntary contractions (MVCs, 10 s duration, 50% duty cycle) or submaximal contractions (50% MVC, 3 s duration, 60% duty cycle). 2. Over the series of thirty MVCs peak elbow torque declined to 57.9 +/- 3.0% (mean +/- S.E.M.) of the initial value while maximal inspiratory pressure declined to 78.7 +/- 7.3% (P < 0.05). For the diaphragm the relative decline in voluntary peak inspiratory (and expulsive) force was similar to the decline in twitch responses to single and twin (10 ms interval) stimuli. However, for the elbow flexors the decline in twitch force was disproportionately greater than the decline in maximal voluntary force. The decline in twitch force for the diaphragm could not be attributed to failure at the neuromuscular junction. 3. At the start of the exercise, twitch potentiation (following three brief MVCs) was significantly less for the diaphragm than for the elbow flexors (20% versus 61%, P < 0.01). 4. In the unfatigued state maximal voluntary efforts by subjects activated 98.4 +/- 0.4% of the stimulated elbow flexors compared with 95.0 +/- 1.5% of the diaphragm (P < 0.05). During the exercise period there was a progressive failure in the ability to activate the limb muscle ('central fatigue'; voluntary drive declined from 98.4 +/- 0.4 to 86.8 +/- 2.2%, P < 0.01) whereas the decline in voluntary activation during inspiratory contractions was not significant (from 95.0 +/- 15 to 91.5 +/- 2.5%). 5. Voluntary activation during attempted maximal efforts was less complete for both muscles when stimuli were delivered without warning. The index of voluntary activation for unwarned stimuli was lower for the diaphragm (performing expulsive efforts, 81.0 +/- 2.8%) than for the limb muscle (89.9 +/- 1.5%, P < 0.01). 6. During repeated submaximal expulsive efforts we confirmed that subjects develop a marked inability to contract the diaphragm voluntarily, but when the diaphragm performed inspiratory manoeuvres at the same level of contractile fatigue, the index of voluntary drive was greater than 94%. 7. In conclusion, when tested with inspiratory efforts the diaphragm developed less central fatigue than the limb muscle over the same exercise period.(ABSTRACT TRUNCATED AT 400 WORDS) (+info)
Elbow and wrist injuries in sports.
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Any disabling injury of the elbow or wrist should be studied roentgenographically for evidence of fracture which may not be otherwise evident but which may cause permanent disability unless the joint is immobilized for healing."Tennis elbow" may be treated with physical therapy and analgesic injection but may require splinting or tendon stripping. Elbow sprain can occur in the growing epiphysis but is rare in adults. A jarring fall on the hand may cause fracture or dislocation at the elbow. Full extension of the joint should be restored gradually by active exercise rather than passive or forcible stretching. Fracture at the head of the radius may cause joint hemorrhage with severe pain which can be relieved by aspiration. A displacing fracture at the head of the radius requires removal of the head to prevent arthritic changes. Myositis ossificans contraindicates operation until after it has cleared. Healing of wrist fractures may be facilitated by exercise of the shoulder and elbow while the wrist is still in a cast. Fractures of the navicular bone are difficult to detect even roentgenographically and splinting may have to be done on clinical evidence alone. (+info)
Upper-limb surgery for tetraplegia.
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We reviewed the results of reconstruction of 97 upper limbs in a consecutive series of 57 tetraplegic patients, treated from 1982 to 1990. Of these, 49 had functional and eight had cosmetic reconstructions. The principal functional objectives were to provide active elbow extension, hook grip, and key pinch. Elbow extension was provided in 34 limbs, using deltoid-to-triceps transfer. Hook grip was provided in 58 limbs, mostly using extensor carpi radialis longus to flexor pollicis longus transfer, and key pinch in 68, mostly using brachioradialis to flexor pollicis longus transfer. Many other procedures were employed. At an average follow-up of 37 months, 70% had good or excellent subjective results, and objective measurements of function compared favourably with other series. Revisions were required for 11 active transfers and three tenodeses, while complications included rupture of anastomoses and problems with thumb interphalangeal joint stabilisation and wound healing. We report a reliable clinical method for differentiating between the activity of extensor carpi radialis longus and brevis and describe a successful new split flexor pollicis longus tenodesis for stabilising the thumb interphalangeal joint. Bilateral simultaneous surgery gave generally better results than did unilateral surgery. (+info)
Exercise heat stress does not reduce central activation to non-exercised human skeletal muscle.
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In this study we measured the central activation ratio (CAR) of the leg extensors and the elbow flexor muscles before and after exhaustive exercise in the heat to determine whether exercise-induced hyperthermia affects the CNS drive to exercised (leg extensors) and/or non-exercised (forearm flexors) muscle groups. Thirteen subjects exercised at fixed intensities representative of a percentage of peak power output (PPO) for 10 min periods (50 %, 40 %, 60 %, 50 %) and then at 75 % PPO until exhaustion in ambient conditions of 39.3 +/- 0.8 degrees C and 60.0 +/- 0.8 % relative humidity. Before and immediately following exercise subjects performed a series of maximal voluntary contractions (MVCs) with the leg extensors (exercised muscles) and forearm flexors (non-exercised muscles). The degree of voluntary activation during the sustained MVCs was assessed by superimposing electrical stimulation to the femoral nerve and the biceps brachii. Exercise to exhaustion increased the rectal temperature from 37.2 +/- 0.2 to 38.8 +/- 0.2 degrees C (P < 0.0001). The mean heart rate at the end of exercise to exhaustion was 192 +/- 3 beats min(-1). Leg extensor voluntary force was significantly reduced from 595 +/- 143 to 509 +/- 105 N following exercise-induced hyperthermia but forearm flexor force was similar before and after exercise. The CAR of the leg extensors decreased from 94.2 +/- 1.3 % before exercise to 91.7 +/- 1.5 % (P < 0.02) following exercise-induced hyperthermia. However, the CAR for the forearm flexors remained at similar levels before and after exercise. The data suggest that the central nervous system selectively reduces central activation to specific skeletal muscles as a consequence of exercise-induced hyperthermia. (+info)