Biomedical subjects

D R Moynes

Publications and source records attributed to D R Moynes.

11 recordsLinked to original sources

PubMed1987

Rehabilitation of shoulder joint instabilities.

The overall goal of the rehabilitation period is a return to full range of motion and a strengthening of the muscles that have a role in protecting the shoulder from injury. Rehabilitation is accomplished gradually and is performed initially in a limited range that excludes the terminal 30 degrees at either end. Two key muscle groups are to be strengthened. One group is for the glenohumeral joint: the deltoid, latissimus dorsi, pectoralis major, and the rotator cuff muscles--especially the subscapularis muscle for internal rotation and the infraspinatus and the teres minor muscles for external rotation. The second group, the trapezius, rhomboids, and serratus anterior muscles, is strengthened for scapular control. Finally, general conditioning and trunk flexibility exercises are critical for a return to former competitive levels.

Exercise Therapy↗

PubMed1986

Electromyography and motion analysis of the upper extremity in sports.

This article reviews the results of studies using electromyographic recordings to determine muscle function during athletic activities. Electromyographic recordings were synchronized with high-speed film to provide information on shoulder muscle firing patterns during baseball pitching, swimming, tennis, and golf. The information obtained about the contributions of specific muscles during these activities may be useful in developing effective injury prevention and rehabilitation strategies.

Baseball↗

PubMed1983

Lower extremity electromyographic analysis of running gait.

Onset of firing for the quadriceps, hamstrings, and gastroc soleus groups during running, both on a treadmill and over ground, was determined in seven normal adult male subjects. Surface and wire electrode data were collected simultaneously from 959 individual gait cycles. The mean velocity over ground was 274 +/- 38 m/minute, with a mean cadence of 171 +/- 14 steps/minute. The treadmill was set at 107 m/minute (4 miles/hour), and the subjects' mean cadence was 147 +/- 11 steps/minute. Over ground, the mean swing/stance ratio was 70/30 +/- 3%, and that for the treadmill was 60/40 +/- 6%. Like muscle groups on the right and left showed a mean difference in onset of muscle activity of 1.3% (+/- 4.6%) when measured during a minimum of ten cycles per subject for each test condition. The average difference in time of onset between the surface and wire electrodes was 2% (SD +/- 4.9%) on the treadmill and 1.5% (SD +/- 3.7%) for over-ground running. These differences are not statistically significant. Surface and wire electrode data have been determined to be equivalent only for regional synergistic muscle groups and should not be extrapolated to compare functions of individual muscles within those groups.

Adult↗

PubMedDate not supplied

An EMG analysis of the shoulder in pitching. A second report.

This is the second report in a series of projects dealing with electromyographic (EMG) analysis of the upper extremity during throwing. Better understanding of the muscle activation patterns could lead to more effective preseason conditioning regimens and rehabilitation programs. Indwelling wire electrodes recorded the output from the biceps, long and lateral heads of the triceps, pectoralis major, latissimus dorsi, serratus anterior, and brachialis for four professional baseball pitchers. These signals were synchronized electronically with high speed film records of a fast ball. The EMG signals were converted from analog to digital records. Results showed that wind-up and early cocking phases showed minimal activity in all muscles, and such firing which occurred was of low intensity. Late cocking, which occurred after the front foot was firmly planted, showed moderate activity in the biceps. Cocking was terminated by the pectoralis major and latissimus dorsi. At this point, the trunk began to rotate forward, while the arm remained elevated and the elbow flexed. Also, the shoulder was moving to maximum external rotation. During the acceleration phase, the biceps was notably quiescent, while the pectoralis major, latissimus dorsi, triceps, and serratus anterior were all active. Muscle action at this time terminated external rotation and elbow flexion; i.e., the muscles fired as decelerators and also initiated the opposite actions for ball acceleration, internal rotation and elbow extension. Follow-through was not only a time of eccentric contraction with muscle activity decelerating the upper extremity complex, it was also an active event with the shoulder moving across the body and the elbow into extension with forearm pronation.

Adult↗

PubMedDate not supplied

Elbow flexion analysis in Bristow patients. A preliminary report.

Seven male nonathletes who had Bristow procedures for shoulder dislocation were analyzed by dynamic electromyography (EMG) and Cybex strength measurement to evaluate the function of elbow flexion. Bilateral strength of elbow flexion also was measured in the 10 controlled subjects to compare the dominant and nondominant arms. The EMG data showed the operated short head of biceps function at low constant intensity, compared with the nonoperated side, while the long head of biceps and brachialis increased their activity. The strength measured by the Cybex demonstrated the elbow flexion on the operated side was not significantly different from the normal group. These data demonstrated that the Bristow procedure reduced the dynamic response of the short biceps which was compensated for by the increase in level of activity of the long heads and brachialis muscle. As a result, normal range of elbow function was restored. Our patients had had intense rehabilitation programs. This appears to be an essential part of the postoperative management to develop the needed compensatory muscle action.

Adult↗

PubMedDate not supplied

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 strokes 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, infraspinatus, middle deltoid, and serratus anterior were predominately recovery phase muscles. The latissimus dorsi and pectoralis major were predominately pull-through phase muscles. The biceps had mixed inconsistent activity during both phases. From dry land quantifications 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.

Adult↗

PubMedDate not supplied

Functional analysis of anterior cruciate ligament instability.

Eighteen males and two females (mean age, 26.5 years) underwent biomechanical assessment and Cybex evaluation prior to ACL reconstruction. Clinically, all patients had at least a 1+ grade with the Lachman, anterior drawer, and pivot shift tests, the majority being graded as 2+. Footswitch, high speed photography, force plate, and indwelling wire electrode data were collected while each subject performed free and fast walking, running, cutting, and stair climbing activities. During walking, single limb support times did not differ between the subject's involved and uninvolved limbs. Knee joint angles were similar between limbs during walking, running, and stair climbing maneuvers. Dynamic EMG tracings during walking demonstrated similar quadriceps and calf activity between limbs, while greater variation in hamstring firing was evident among subjects. During running, the involved limb had a longer duration of medial hamstring activity compared to the lateral hamstring. No significant differences were seen in either vertical or sagittal shear forces during free walking. During fast walking, higher midstance vertical forces (F2) were present in the involved limb (P less than 0.05). During running, the involved limb experienced lower vertical forces (P less than 0.05), while both anterior and posterior sagittal shear differences were insignificant. Straight cut maneuvers demonstrated significantly lower lateral shear and vertical forces in the involved limb (P less than 0.05). Lower lateral and sagittal shear forces in the involved limb (P less than 0.01 and P less than 0.05, respectively), combined with a reduced angle of the cut during the cross-cut maneuver, may be the first means to assess the functional pivot shift phenomenon ever documented.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Rotator cuff function during a golf swing.

A study of bilateral shoulder muscle activity during the golf swing was undertaken using electromyography and high-speed photography. Understanding of the muscle firing patterns could lead to injury prevention and development of appropriate training and conditioning regimens. The swings of seven adult male right-handed professional golfers without shoulder problems were examined. Indwelling electrodes were inserted into the supraspinatus, subscapularis, infraspinatus, latissimus dorsi, pectoralis major, anterior deltoid, middle deltoid, and posterior deltoid on the right side. Each subject was allowed to warm up until he felt comfortable. Films of each subject were taken at 450 frames per second. The swing was broken into four segments to which electromyographic signals were synchronized electronically. The EMG tracings were subjected to analog-to-digital conversion and a relative measure of quantity obtained. All tests were repeated on the left side for each subject. Results indicate that all portions of the deltoid were inactive on the right side throughout the swing. The deltoid was likewise inactive on the left except for a brief spurt from the anterior portion during the milliseconds immediately preceding ball contact. Of the rotator cuff muscles, on the left the supraspinatus fired at a low level throughout the swing, as did the infraspinatus. The latter had a slightly larger burst of activity immediately after ball contact. The subscapularis was more active than any other muscle throughout the swing. The cuff muscles on the right side showed as much activity overall as those on the left. In addition, the latissimus dorsi and pectoralis major seemed to provide power bilaterally, with marked activity during the acceleration phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

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 understand 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 difference, 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.

Adult↗

PubMedDate not supplied

A comparative electromyographic analysis of the shoulder during pitching. Professional versus amateur pitchers.

Dynamic, fine-wire, intramuscular electromyography (EMG) was performed on 12 different shoulder muscles in 13 normal male subjects as they pitched a baseball. Seven were major league baseball pitchers and six were amateur pitchers. The act of pitching a fast ball was filmed at 450 frames per second with the EMG signals recorded synchronously. The subscapularis, supraspinatus, and infraspinatus muscles were tested in 13 subjects, the biceps brachii muscle was tested in 12, and other shoulder muscles were tested variously among the subjects. Two groups of muscles were identified. Group I muscles, the supraspinatus, infraspinatus, teres minor, deltoid, trapezius, and biceps brachii, served primarily to position the shoulder and elbow for the delivery of the pitch. These muscles were found to have greater activity during the early and late cooking stages, with less activity during acceleration. Group II muscles accelerated the arm and baseball forward in space. These muscles, the pectoralis major, serratus anterior, subscapularis, and latissimus dorsi, had stronger activity during the propulsive phase of the pitch. The professional pitchers were able to use the muscles about the shoulder in an efficient manner to achieve greater pitching velocities. The subscapularis and latissimus dorsi muscles of Group II had stronger activity among the professionals, whereas the supraspinatus, teres minor, and biceps brachii muscles of Group I had only minimal activity. The amateurs, on the other hand, continued to use all of the rotator cuff muscles and the biceps brachii muscle of Group I through the acceleration stage of the pitch.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

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, middle 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 synchronized 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 groundstrokes. 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 backhand. The serratus anterior demonstrates intense activity 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 groundstrokes are accomplished by complex sequences of muscle activity that incorporate contributions from the lower extremities and trunk into smooth, coordinated patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗