Biomedical subjects

Philip W McClure

Publications and source records attributed to Philip W McClure.

7 recordsLinked to original sources

PubMed2006

Scapulothoracic and glenohumeral kinematics following an external rotation fatigue protocol.

STUDY DESIGN: Repeated-measures experimental design. OBJECTIVE: To determine the effects of shoulder external rotator muscle fatigue on 3-dimensional scapulothoracic and glenohumeral kinematics. BACKGROUND: The external rotator muscles of the shoulder are important for normal shoulder function. Impaired performance of these muscles has been observed in subjects with impingement syndrome and it is possible that external rotator muscle fatigue leads to altered kinematics of the shoulder girdle. METHODS AND MEASURES: Twenty subjects without a history of shoulder pathology participated in this study. Three-dimensional scapulothoracic and glenohumeral kinematics were determined from electromagnetic sensors attached to the scapula, humerus, and thorax. Surface electromyographic (EMG) data were collected from the upper and lower trapezius, serratus anterior, anterior and posterior deltoid, and infraspinatus muscles. Median power frequency (MPF) values were derived from the raw EMG data and were used to indicate the degree of local muscle fatigue. Kinematic and EMG measures were collected prior to and immediately following the performance of a shoulder external rotation fatigue protocol. RESULTS: After completing the fatigue protocol subjects demonstrated less external rotation of the humerus. Additionally, they had less posterior tilt of the scapula in the beginning phase of arm elevation, and more scapular upward rotation and clavicular retraction in the mid ranges of arm elevation. CONCLUSIONS: Performance of an external rotation fatigue protocol results in altered scapulothoracic and glenohumeral kinematics. Further studies are needed to investigate the effects of external rotator muscle fatigue on scapulothoracic and glenohumeral kinematics in subjects with shoulder pathology.

Adolescent↗

PubMed2006

Shoulder function and 3-dimensional scapular kinematics in people with and without shoulder impingement syndrome.

BACKGROUND AND PURPOSE: Several factors such as posture, muscle force, range of motion, and scapular dysfunction are commonly believed to contribute to shoulder impingement. The purpose of this study was to compare 3-dimensional scapular kinematics, shoulder range of motion, shoulder muscle force, and posture in subjects with and without primary shoulder impingement syndrome. SUBJECTS: Forty-five subjects with impingement syndrome were recruited and compared with 45 subjects without known pathology or impairments matched by age, sex, and hand dominance. METHODS: Shoulder motion and thoracic spine posture were measured goniometrically, and force was measured with a dynamometer. An electromagnetic motion analysis system was used to capture shoulder kinematics during active elevation in both the sagittal and scapular planes as well as during external rotation with the arm at 90 degrees of elevation in the frontal plane. RESULTS: The impingement group demonstrated slightly greater scapular upward rotation and clavicular elevation during flexion and slightly greater scapular posterior tilt and clavicular retraction during scapular-plane elevation compared with the control group. The impingement group demonstrated less range of motion and force in all directions compared with the control group. There were no differences in resting posture between the groups. DISCUSSION AND CONCLUSION: The kinematic differences found in subjects with impingement may represent scapulothoracic compensatory strategies for glenohumeral weakness or motion loss. The decreased range of motion and force found in subjects with impingement support rehabilitation approaches that focus on strengthening and restoring flexibility.

Adult↗

PubMed2005

Effects of shoulder muscle fatigue caused by repetitive overhead activities on scapulothoracic and glenohumeral kinematics.

The purpose of this study was to determine the effects of shoulder muscle fatigue on three dimensional scapulothoracic and glenohumeral kinematics. Twenty healthy subjects participated in this study. Three-dimensional scapulothoracic and glenohumeral kinematics were determined from electromagnetic sensors attached to the scapula, humerus, and thorax. Surface electromyographic (EMG) data were collected from the upper and lower trapezius, serratus anterior, anterior and posterior deltoid, and infraspinatus muscles. Median power frequency (MPF) values were derived from the raw EMG data and were used to indicate the degree of local muscle fatigue. Kinematic and EMG measures were collected prior to and immediately following the performance of a shoulder elevation fatigue protocol. Following the performance of the fatigue protocol subjects demonstrated more upward and external rotation of the scapula, more clavicular retraction, and less humeral external rotation during arm elevation. All muscles with the exception of the lower trapezius showed EMG signs of fatigue, the most notable being the infraspinatus and deltoid muscles. In general, greater scapulothoracic motion and less glenohumeral motion was observed following muscle fatigue. Further studies are needed to determine what effects these changes have on the soft tissues and mechanics of the shoulder complex.

Adolescent↗

PubMed2005

Three-dimensional scapulothoracic motion during active and passive arm elevation.

BACKGROUND: Scapulothoracic muscle activity is believed to be important for normal scapulothoracic motion. In particular, the trapezius and serratus anterior muscles are believed to play an important role in the production and control of scapulothoracic motion. The aim of this study was to determine the effects of different levels of muscle activity (active versus passive arm elevation) on three-dimensional scapulothoracic motion. METHODS: Twenty subjects without a history of shoulder pathology participated in this study. Three-dimensional scapulothoracic motion was determined from electromagnetic sensors attached to the scapula, thorax and humerus during active and passive arm elevation. Muscle activity was recorded from surface electrodes over the upper and lower trapezius, serratus anterior, anterior and posterior deltoid, and infraspinatus muscles. Differences in scapulothoracic motion were calculated between active and passive arm elevation conditions. FINDINGS: Scapular motion was observed during the trials of passive arm elevation; however, there was more upward rotation of the scapula, external rotation of the scapula, clavicular retraction, and clavicular elevation under the condition of active arm elevation. This was most pronounced for scapular upward rotation through the mid-range (90-120 degrees) of arm elevation. INTERPRETATION: The upper and lower trapezius and serratus anterior muscles have an important role in producing upward rotation of the scapula especially throughout the mid-range of arm elevation. Additionally, it appears that capsuloligamentous and passive muscle tension contribute to scapulothoracic motion during arm elevation. Assessment of the upper and lower trapezius and serratus anterior muscles and upward rotation of the scapula should be part of any shoulder examination.

Adolescent↗

PubMed2004

Shoulder function and 3-dimensional kinematics in people with shoulder impingement syndrome before and after a 6-week exercise program.

BACKGROUND AND PURPOSE: Shoulder impingement syndrome is a common condition and is often managed with an exercise program. The purpose of this study was to examine an exercise program in patients with shoulder impingement syndrome. Specifically, the purpose was to identify changes that might occur in 3-dimensional scapular kinematics, physical impairments, and functional limitations. SUBJECTS: Fifty-nine patients with impingement syndrome were recruited, and 39 patients successfully completed the 6-week rehabilitation program and follow-up testing. Impingement was defined as having at least 3 of 6 predefined clinical signs or symptoms. METHODS: Subjects were assessed before and after a 6-week rehabilitation program and again at 6 months. Pain, satisfaction, and function were measured using the University of Pennsylvania Shoulder Scale. Range of motion, isometric muscle force, and 3-dimensional scapular kinematic data also were collected. Subjects were given a progressive exercise program that included resistive strengthening, stretching, and postural exercises that were done daily at home. Subjects also were given shoulder education related to anatomy, the basic mechanics of impingement, and strategies for reducing load on the shoulder. Each subject attended one physical therapy session per week for a 6-week period, primarily for monitoring and upgrading the exercise program. Pretest and posttest scores were compared using paired t tests and repeated-measures analysis of variance. RESULTS: Passive range of motion increased for both external and internal rotation but not for elevation. Abduction external and internal rotation force all increased. There were no differences in scapular kinematics. Improvements were found for pain, satisfaction, and shoulder function and for Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) scores related to physical function. At 6-month follow-up, improvements made in pain, satisfaction, and function were maintained. DISCUSSION AND CONCLUSION: The use of this exercise protocol in the management of shoulder impingement syndrome may have a positive impact on patients' impairments and functional limitations. Our findings suggest a relatively simple exercise program combined with patient education may be effective and, therefore, merits study in a larger trial using a control group. Changes in scapular kinematics did not appear to be a primary mechanism underlying improvement in symptoms and function.

Adult↗

PubMed2003

Anatomical and biomechanical mechanisms of subacromial impingement syndrome.

Subacromial impingement syndrome is the most common disorder of the shoulder, resulting in functional loss and disability in the patients that it affects. This musculoskeletal disorder affects the structures of the subacromial space, which are the tendons of the rotator cuff and the subacromial bursa. Subacromial impingement syndrome appears to result from a variety of factors. Evidence exists to support the presence of the anatomical factors of inflammation of the tendons and bursa, degeneration of the tendons, weak or dysfunctional rotator cuff musculature, weak or dysfunctional scapular musculature, posterior glenohumeral capsule tightness, postural dysfunctions of the spinal column and scapula and bony or soft tissue abnormalities of the borders of the subacromial outlet. These entities may lead to or cause dysfunctional glenohumeral and scapulothoracic movement patterns. These various mechanisms, singularly or in combination may cause subacromial impingement syndrome.

Biomechanical Phenomena↗

PubMedDate not supplied

American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, patient self-report section: reliability, validity, and responsiveness.

The purpose of this study was to examine the psychometric properties of the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), patient self-report section. Patients with shoulder dysfunction (n = 63) completed the ASES, The University of Pennsylvania Shoulder Score, and the Short Form-36 during the initial evaluation, 24 to 72 hours after the initial visit, and after 3 to 4 weeks of physical therapy. The test-retest reliability (intraclass correlation coefficient[1-way random-effects], 0.84; 95% CI lower limit, 0.75) and internal consistency (Cronbach alpha, 0.86) values were acceptable. The standard error of the measure was 6.7 ASES points (90% CI, 11.0). Construct and discriminant validity was demonstrated. Responsiveness was demonstrated with a standardized response mean of 1.5 and an effect size of 1.4. The minimal detectable change was 9.7 ASES points (90% CI, 16), and the minimal clinically important difference was 6.4 ASES points. The results indicate that the ASES is a reliable, valid, and responsive outcome tool.

Adult↗