Biomedical subjects

F W Jobe

Publications and source records attributed to F W Jobe.

95 records · Page 6Linked to original sources

PubMedDate not supplied

Electromyographic analysis of the scapular muscles during a golf swing.

To describe the role of the scapular muscles in the golf swing, we studied 15 competitive male golfers. Four muscles were studied bilaterally using dynamic electromyography and cinematography. In the trailing arm, the levator scapulae elevates while the rhomboid muscles retract the scapula during takeaway; both then stabilize the scapula through the remainder of the swing. In the leading arm, these muscles retract the scapula during forward swing and acceleration. The trapezius muscle in the trailing arm also demonstrates high activity during takeaway to aid in scapular retraction. In the leading arm, trapezius activity is high in forward swing and through the remainder of the swing to promote scapular retraction. The serratus anterior muscle activity is high in the trailing arm during forward swing and through the remainder of the swing to maximize scapular protraction. In the leading arm, the serratus anterior muscle has constant activity through all phases of the swing, which may explain the clinical scenario of muscle fatigue in high demand golfers. The golf swing and uncoiling action requires that the scapular muscles work in synchrony to maximize swing arc and clubhead speed. This study demonstrates the importance of the scapular muscles in the golf swing and the need for specific strengthening exercises.

Adult↗

PubMedDate not supplied

Functional anatomy of the flexor pronator muscle group in relation to the medial collateral ligament of the elbow.

To describe the relationship of the pronator teres, flexor carpi radialis, flexor digitorum superficialis, and flexor carpi ulnaris muscles to the medial collateral ligament at 30 degrees, 90 degrees, and 120 degrees of elbow flexion, we dissected 11 cadaveric specimens. The flexor carpi ulnaris muscle is the predominant musculotendinous unit overlying the medial collateral ligament in the majority of cases and is the only one at 120 degrees of elbow flexion. The flexor digitorum superficialis muscle is the only other significant contributor. The medial collateral ligament is the primary stabilizer of the medial elbow with elbow flexion greater than 30 degrees, as in throwing. The flexor carpi ulnaris muscle, because of its position directly over the medial collateral ligament, and the flexor digitorum superficialis muscle, with its near proximity and relatively large bulk, are the specific muscles best suited to provide medial elbow support. This is especially relevant to overhand throwing athletes who encounter extreme valgus force across the elbow during the cocking and acceleration phases of the throwing motion. Exercise and conditioning of the medial elbow musculature, specifically the flexor digitorum superficialis muscle and the flexor carpi ulnaris muscle, may prevent injury or assist in rehabilitation of medial elbow instability, especially in overhand throwing athletes.

Acceleration↗

PubMedDate not supplied

Shoulder muscle firing patterns during the windmill softball pitch.

The purpose of this study was to describe the activity of eight shoulder muscles during the windmill fast-pitch softball throw. Ten collegiate female pitchers were analyzed with intramuscular electromyography, high-speed cinematography, and motion analysis. The supraspinatus muscle fired maximally during arm elevation from the 6 to 3 o'clock position phase, centralizing the humeral head within the glenoid. The posterior deltoid and teres minor muscles acted maximally from the 3 to 12 o'clock position phase to continue arm elevation and externally rotate the humerus. The pectoralis major muscle accelerated the arm from the 12 o'clock position to ball release phase. The serratus anterior muscle characteristically acted to position the scapula for optimal glenohumeral congruency, and the subscapularis muscle functioned as an internal rotator and to protect the anterior capsule. Although the windmill softball pitch is overtly different from the baseball pitch, several surprising similarities were revealed. The serratus anterior and pectoralis major muscles work in synchrony and seem to have similar functions in both pitches. Although the infraspinatus and teres minor muscles are both posterior cuff muscles, they are characteristically uncoupled during the 6 to 3 o'clock position phase, with the infraspinatus muscle acting more independently below 90 degrees. Subscapularis muscle activity seems important in dynamic anterior glenohumeral stabilization and as an internal rotator in both the baseball and softball throws.

Adolescent↗

PubMedDate not supplied

Medial elbow problems in the overhead-throwing athlete.

The elbow is subjected to enormous valgus stresses during the throwing motion, which places the overhead-throwing athlete at considerable risk for injury. Injuries involving the structures of the medial elbow occur in distinct patterns. Although acute injuries of the medial elbow can occur, the majority are overuse injuries as a result of the repetitive forces imparted to the elbow by throwing. Injury to the ulnar collateral ligament complex results in valgus instability. Valgus extension overload leads to diffuse osseous changes within the elbow joint and secondary posteromedial impingement. Overuse of the flexor-pronator musculature may result in medial epicondylitis and occasional muscle tears and ruptures. Ulnar neuropathy is a common finding that may be due to a variety of factors, including traction, friction, and compression of the ulnar nerve. Advances in nonoperative and operative treatment regimens specific to each injury pattern have resulted in the restoration of elbow function and the successful return of most injured overhead athletes to competitive activities. With further insight into the relevant anatomy, biomechanics, and pathophysiology involved in overhead activities and their associated injuries, significant contributions can continue to be made toward prevention and treatment of these injuries.

Athletic Injuries↗

PubMedDate not supplied

Analysis of 100 patients with anterolateral rotatory instability of the knee.

Of 100 consecutive patients with anterolateral rotatory instability analyzed, 84 were males and the average age was 27.4 years. Over 50 per cent were injured while participating in athletics and 40 per cent were injured during daily activities. The group averaged 1.2 operations prior to diagnosis. The most frequently performed procedures were medial meniscectomy, pes anserinus transfer and medial capsular reefings. Eighty-four of 100 patients underwent surgery during the study period. Seventy-one had combined rotatory instability and 13 had anterior lateral rotatory instability alone. Sixty-six patients had articular cartilage damage. Before treating the anterolateral rotatory instability, it is necessary to identify and treat other commonly associated abnormalities.

Adolescent↗