Daniel J. Antonelli

Energy cost of walking of amputees: the influence of level of amputation

A comparison of selected gait parameters and the energy cost of prosthetic walking was made in seventy patients with unilateral traumatic and vascular amputations. Amputations above the knee, below the knee, and at the Symes level were compared in both groups of amputees, and a control group of forty normal subjects also studied. In both groups of amputees performance was significantly better the lower the level of the amputation. When preservation of function is the chief concern, amputation should be performed at the lowest possible level.

Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability

Fifteen male athletes who were skilled in throwing and who had chronic anterior instability of the shoulder (Group 1) were evaluated by dynamic intramuscular electromyography while pitching a baseball. Indwelling wire electrodes recorded the levels of activity in the biceps, middle deltoid, supraspinatus, infraspinatus, pectoralis major, subscapularis, latissimus dorsi, and serratus anterior throughout the entire pitching sequence. These signals were synchronized electronically with records of the pitch that were made using high-speed photography. The pitch was divided into five phases: wind-up, early cocking, late cocking, acceleration, and follow-through. The results were compared with previous identical studies of twelve healthy, uninjured male athletes who were skilled in throwing (Group 2). Activity increased mildly in the biceps and supraspinatus in Group 1 as compared with Group 2. Similar patterns of activity were demonstrated in the deltoid. In Group 1 the infraspinatus had increased activity during early cocking and follow-through but had decreased activity during late cocking. The pectoralis major, subscapularis, latissimus dorsi, and serratus anterior in Group 1 all were shown to have markedly decreased activity. The study revealed a difference between Groups 1 and 2 in all of the muscles of the shoulder that were tested with the exception of the deltoid. The mildly increased activity levels of the biceps and supraspinatus that were found in Group 1 may compensate for anterior laxity. The marked reduction in activity in the pectoralis major, subscapularis, and latissimus dorsi added to the anterior instability by decreasing the normal internal-rotation force that is needed during the phases of late cocking and acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

An electromyographic analysis of shoulder function in tennis players

Shoulder injuries in tennis players are common because of the repetitive, high-magnitude forces generated around the shoulder during the various tennis strokes. An understanding of the complex sequences of muscle activity in this area may help reduce injury, enhance performance, and assist the rapid rehabilitation of the injured athlete. The supraspinatus, infraspinatus, subscapularis, mid dle deltoid, pectoralis major, latissimus dorsi, biceps brachii, and serratus anterior muscles were studied in six uninjured male Division II collegiate tennis players using dynamic electromyography (EMG) and synchro nized high-speed photography. Each subject performed the tennis serve and the forehand and backhand groundstrokes, and each stroke was divided into stages. The tennis serve contains four stages. Three stages characterize the forehand and backhand ground strokes. Our results indicate that the subscapularis, pectoralis major, and serratus anterior display the greatest activity during the serve and forehand. The middle deltoid, supraspinatus, and infraspinatus are most active in the acceleration and follow-through stages of the backhand. The biceps brachii increases its activity during cocking and follow-through in the serve with a similar pattern noted in the acceleration and follow-through stages of the forehand and back hand. The serratus anterior demonstrates intense activ ity in the serve and forehand, thus providing a stable platform for the humeral head and assisting in gleno humeral-scapulothoracic synchrony. The tennis serve and forehand and backhand ground strokes are accomplished by complex sequences of muscle activity that incorporate contributions from the lower extremities and trunk into smooth, coordinated patterns. Although our study focused on shoulder function in the uninjured tennis player, it may provide a basis for understanding abnormal shoulder biomechanics that contribute to pain and dysfunction. The serratus anterior deserves special emphasis, for our study showed that its activity is essential to each of the three tennis strokes. Because of the similarities between the tennis serve and overhead throw, a conditioning program comparable to one pitchers use many be appropriate for tennis players.

Gait Analysis of the Triceps Surae in Cerebral Palsy: A Preoperative And Postoperative Clinical And Electromyographic Study

Preoperative static clinical evaluation of the spastic triceps surae often fails to indicate which of the two muscles (soleus or gastrocnemius) is the more distorted in its phasic activity during walking or in response to stretch. Gait electromyography is a method of distinguishing gastrocnemius from soleus problems. We customarily perform electromyographic studies prior to surgery. If isolated gastrocnemius phase distortion or clonus, or both, is found, a gastrocnemius recession is performed. When combined soleus and gastrocnemius problems are noted an Achilles-tendon lengthening is done.

An electromyographic analysis of the elbow in pitching

Elbow injuries are common in baseball pitchers. Curve balls are thought to increase this risk, particularly if the athlete begins throwing this pitch at an early age. The purpose of this paper is to identify forearm muscle firing patterns during the pitching cycle in an effort to under stand this etiology. Dynamic EMG was performed on eight collegiate pitchers to evaluate extensor digitorum communis, brachioradialis, flexor carpi radialis, flexor digitorum superficialis, extensor carpi radialis longus, extensor carpi radialis brevis, pronator teres, and supinator. Each subject threw a fast ball and curve ball, which were filmed at 450 frames per second and synchronized with the EMG. These signals were converted from analog to digital records. Results showed low to moderate activity in all muscles during all phases of the pitch. The function is probably positioning to accept the transfer of energy from the larger trunk and girdle structures. The most notable difference between the fast ball and curve ball is a slight increase in the extensor carpi radialis longus and extensor carpi radialis brevis activity during late cocking, acceleration, and follow-through of the curve ball as compared to the fast ball. This differ ence, however, is not significant. In addition, there was no significant difference between the fast ball and the curve ball in the flexor-pronator group in any phase. We cannot substantiate that medial elbow problems are a result of an increase in the use of flexor muscles during the curve ball pitch.

Fine wire electromyography analysis of muscles of the shoulder during swimming

Fine wire EMG of the shoulder was performed on 11 swimmers; 5 performed during dry land studies and 7 during aquatic studies. One individual underwent both studies. A cinematographic analysis was synchronized with the EMG data to determine what muscles were firing at each phase of the swim stroke. Eight muscles were studied: biceps, subscapularis, latissimus dorsi, pectoralis major, supraspinatus, infraspinatus, serratus anterior, and deltoid. Three stokes were analyzed: freestyle, breaststroke, and butterfly. The freestyle and butterfly are frequently associated with impingement type syndromes in swimmers. It was determined that the supraspinatus, infraspi natus, middle deltoid, and serratus anterior were pre dominately recovery phase muscles. The latissimus dorsi and pectoralis major were predominately pull- through phase muscles. The biceps had mixed incon sistent activity during both phases. From dry land quan tifications of the EMG signal it was determined that the serratus anterior functions near maximal muscle test during each stroke, and theoretically may fatigue with repetition. It is hoped that a training program aimed to strengthen the scapular rotators may help alleviate impingement syndrome in swimmers.

Electromyography before and after surgery for hip deformity in children with cerebral palsy. A comparison of clinical and electromyographic findings

Twenty-three ambulatory children with spastic diplegic cerebral palsy were evaluated clinically and by electromyography before and after hip-muscle surgery. The stretch tests originally designed to distinguish specific muscle tightness and spasticity were found to be non-specific when tested by electromyography. Ambulatory electromyograms using needle electrodes and telemetry generally showed decreased activity in the released muscles and, on occasion, changes in activity in muscles not operated on. These unanticipated changes after release may explain some of the unpredictability of results of such procedures in cerebral palsy.