GLOSARIO DE TÉRMINOS

Interventions to correct forward head and rounded shoulder posture have been investigated in both clinical and laboratory settings.(Kebaetse, McClure et al. 1999; Wang, McClure et al. 1999; Roddey 2002) A sample of 38 healthy subjects were classified by resting head and shoulder posture as defined by Kendall(1952) as either normal, mild forward head and rounded shoulder posture, or marked forward head and

et al.(1990). Subjects were randomly assigned to either a treatment or control group then given common pectoral stretching exercises. Each group’s posture was reassessed after 2 weeks by measuring their forward head angle and scapular abduction.

Forward head angle and scapular abduction improved following the treatment for the moderate forward head and rounded shoulder group. The authors concluded that clinicians may expect individuals with the greatest forward head and rounded shoulder posture to respond the most from a stretching intervention. Additionally, the authors noted limitations of mostly female, young (18-25), and healthy sample. Finally, while the change scores presented were less than 3% of the scapular abduction measure a moderate (.61) effect size was observed. This suggests that in a healthy, young population posture can be improved as measured by scapular abduction.

The effects of exercise interventions and shoulder posture have also been examined on three-dimensional scapular kinematics. (Wang, McClure et al. 1999) Twenty subjects asymptomatic for shoulder pain but with forward shoulder posture were analyzed for scapular kinematics. At entry into the study, anatomical landmarks from the subjects’ scapula, and spine, as well as two points from a plastic bar strapped to the humerus were digitized with an electromechanical digitizer. These digitized points gave position and orientation coordinates for the landmarks, which were then processed to give segmental position and orientation. Data were collected at rest (arm at side), abducted in the scapular plane to horizontal, and at maximum abduction in the scapular plane. After the initial data collection, subjects were instructed in a six-week home exercise program. The program was designed to mimic a clinical regimen aimed at restoring muscle balance around the shoulder girdle. The program included resisted strengthening exercises using

thera-band, as well as a corner stretch for the pectoralis muscles. The exercise program was performed three times per week for six weeks. Ten repetitions of pectoralis stretches were performed and were held for ten seconds each, with five repetitions added every two weeks.

Decreased scapular upward rotation and increased scapular internal rotation at horizontal were observed following the intervention. There was also a decrease in scapular superior translation at horizontal and a decrease in upper thoracic inclination at all three positions. The authors discuss the decreased scapular upward rotation in light of previous work that has shown that decreased upward rotation was demonstrated in

subjects with subacromial impingement.(Lukasiewicz 1999) They propose that perhaps the strengthening program created stronger muscles to stabilize the scapula on the thorax, allowing improved efficiency of motion. Another possible explanation proposed is stronger rotator cuff muscles to facilitate glenohumeral motion. The explanation for increased internal rotation given is that increased strength of the upper portion of the serratus anterior promoted this motion.

Limitations include the use of three static, rather than continuous measurements. Repeating palpation and digitization at these three positions may introduce error. In addition, the group was not symptomatic for shoulder pain so patient motivation may have been limited. No occupational or recreational activities were considered as

covariates. It was also a relatively young population and results might not be similar with an older population.

Ludewig and Borstad(2000) examined the effects of a home exercise program on shoulder pain and function in construction workers. Workers with shoulder pain

consistent with shoulder impingement and confirmed with a clinical examination were randomized into an exercise group or control group. The exercise intervention consisted of two stretching exercises, two strengthening exercises, and one relaxation exercise. A daily bilateral pectoralis minor stretch was included in the eight-week exercise program. A subjective survey determined the effects of the exercises on shoulder pain and function. There was a statistically significant interaction of group and time. Subjects in the

intervention group demonstrated significant improvements in pain and satisfaction with their shoulder, and improvements in work-related pain and disability scores at post-test.

McClure et al (2004) completed a similar study evaluating the effects of a supervised exercise program on three-dimensional scapular kinematics, physical

impairments, and functional limitations in patients diagnosed with shoulder impingement syndrome. Thirty-nine patients completed the 6-week program which consisted of

strengthening and stretching of both the glenohumeral and scapular impairments often reported in patients with shoulder impingement syndrome. Three-dimensional scapular kinematics, glenohumeral range of motion, thoracic posture, glenohumeral isometric strength, and self-reported pain and function were recorded pre and post intervention.

Increases in glenohumeral muscle force for internal and external rotation, glenohumeral internal and external rotation, concurrent with decreases in self reported pain, increased function, and increased satisfaction. No differences were observed for scapular kinematics or thoracic posture. Glenohumeral internal rotation range of motion and external rotation strength were significantly correlated with increases in self report scores. It was concluded that these physical impairments are important to address in patients with shoulder impingement syndrome.

While the exercise program seems be effective, these results are limited by the lack of control group, dropout rate, and progression of the exercise program. The authors note the limitations as a result of no control group and dropout rate constraining

conclusions by the unknown natural history of shoulder pain. The absence of observed changes in scapular kinematics is likely due to the lack of emphasis on humeral elevation in the exercise program. Passive humeral elevation did not increase during the treatment program. Therefore given the coupled nature of humeral and scapular motion it is not surprising that not differences were observed in scapular kinematics. The difficulty in observing differences in scapular kinematics has been noted by several authors and is due to high between subject variability and the measurement error associated with skin motion.(van der Helm 1997; Ludewig and Cook 2000)