Comparison of Exercise Interventions in Adults With Subacromial Impingement Syndrome

• Change in Pain-free shoulder flexion [ Time Frame: baseline and after 3 and 6 weeks of intervention ] [ Designated as safety issue: No ]
  Participants will be assessed for pain-free active range of motion of shoulder flexion using a digital inclinometer. Seated participants will be asked to perform the flexion movement as far as they are able to without pain and without trunk or other motion substitution
• Change in Shoulder pain [ Time Frame: baseline, after 3 weeks and 6 weeks of intervention ] [ Designated as safety issue: Yes ]
  The numeric pain rating scale (NPRS) will be used to assess shoulder pain. The NPRS is a verbal scale used to attach a value to the participants' pain level when questioned. Zero on the scale indicates no pain; one to three indicates mild pain, four to six for moderate pain, and seven to ten for severe pain.
• Change in Shoulder function [ Time Frame: baseline and after 3 and 6 weeks of intervention ] [ Designated as safety issue: No ]
  Shoulder function in this study will be assessed using the disabilities of the arm, shoulder, and hand (DASH). The DASH is a 30-question instrument that uses a five point Likert scale to rate the respondent's ability to perform daily activities using their upper extremity. Activities such as "prepare a meal" are rated from "1, no difficulty" to "5 unable" to perform. Thirty is subtracted from the total score of the items with the result divided 1.20 to arrive at a score that is a percentage of 100. A score of zero indicates no disability and a score of 100 indicates total disability.
• Change in Shoulder Abduction strength [ Time Frame: baseline and after 3 and 6 weeks of intervention ] [ Designated as safety issue: No ]
  Isometric strength for shoulder abduction will be assessed using a hand-held dynamometer and will be tested in supine with the shoulder in 90° of abduction and 90° of elbow flexion with the forearm in neutral. Resistance will be applied perpendicular to the distal humerus just above the lateral epicondyle of the elbow. Participants will hold the aforementioned position as the examiner applies the force through the dynamometer with the participant building up to maximal tension in one to two seconds and continuing to maintain the tension for four to five more seconds.
• Change in Shoulder external rotation strength [ Time Frame: baseline and after 3 and 6 weeks of intervention. ] [ Designated as safety issue: No ]
  Isometric strength for shoulder external rotation will be assessed using a hand-held dynamometer and will be tested in supine with the shoulder in 90° of abduction and 90° of elbow flexion with the forearm in neutral. Resistance will be applied perpendicular to the dorsal distal forearm one inch proximal to the ulnar styloid. Participants will hold the aforementioned position as the examiner applies the force through the dynamometer with the participant building up to maximal tension in one to two seconds and continuing to maintain the tension for four to five more seconds.
• Change in Pain-free shoulder scapular plane elevation [ Time Frame: baseline and after 3 and 6 weeks of intervention ] [ Designated as safety issue: No ]
  Participants will be assessed for pain-free active range of motion of shoulder scapular plane elevation using a digital inclinometer. Participants will be asked to perform the scapular plane elevation movement as far as they are able to without pain and without trunk or other motion substitution

The purpose of this study is to compare two different physical therapy exercise programs in persons who have shoulder pain in order to determine if they have a different affect on pain level and ability to use the injured shoulder after treatment. Both exercise groups will attend physical therapy for an hour,two to three times a week, for eight weeks. The first two weeks of therapy sessions will involve learning the exercises and testing to determine what weight to use during exercises. One group will perform a traditional therapy exercise program for shoulders using hand weights. The other group will perform a version of the same shoulder exercises but with a different exercise technique. Exercises in both programs are part of the standard of care for shoulder impingement in physical therapy but one program concentrates on the lowering portion of the exercise (eccentrics) while the other emphasizes the lifting portion of the exercise (concentrics). Both groups will perform the same warm-up, stretching, and cool-down exercises. Participants will also be required to perform a daily home exercise program of stretches and range of motion that will take about 20 minutes to complete. Exercise testing will determine the hand weight resistance used by each person during their therapy sessions and re-testing will occur every two weeks to determine any changes in the weight used for the exercises to keep them challenging. Pain level, ability to use the injured arm for daily activities, strength, and amount of movement in the shoulder, will be measured at the start of physical therapy and after five and eight weeks (end of study) of the exercise treatments. A concurrent study investigating the reliability of the shoulder motion and strength measurements used in the larger study will also be performed.

Research hypotheses:

1. Adults with shoulder pain who complete the eccentric progressive resistive exercise intervention will demonstrate significantly greater improvements in the outcome measures at three weeks, earlier in the intervention, than the concentric progressive resistive exercise intervention group.
2. Adults with shoulder pain who perform progressive resistive exercise interventions, regardless of contraction type, will demonstrate significant improvement in the shoulder outcome measures at three and six weeks of intervention.

This study will be a prospective, repeated-measure, randomized clinical trial comparing shoulder outcome measures in adults with SAIS following eccentric or concentric progressive resistance exercise intervention programs. Subjects: 36 persons with SAIS, aged 18 and older, will be recruited from the Texas Health Resources Dallas outpatient rehabilitation department and referring physicians. Procedures: Participants will be randomly assigned to either a concentric or eccentric intervention group. Participants will complete outcome measures for pain intensity, shoulder function, shoulder pain-free active range of motion (AROM) of flexion and scapular plane elevation, and shoulder pain-free strength of external rotation and abduction. Outcomes will be assessed by an investigator blinded to group assignment at baseline and after three and six weeks of intervention. Interventions will consist of supervised exercise sessions three times a week. Exercise progression will follow a standardized and systematic approach. The reliability of the AROM and strength outcome measures will be assessed concurrently using a random subset of six participants from each group.

• Active Comparator: Concentric exercise group
  The participants in this group will perform the intervention exercises by actively completing the lifting portion of the resistive shoulder exercises. The physical therapist will then perform the lowering portion of the exercise for the participant.
  Intervention: Other: Shoulder resistive exercise
• Experimental: Eccentric exercise group
  The participants in this group will actively perform the lowering portion of the resistive shoulder exercises in the intervention. The physical therapist will perform the lifting portion of the exercise for the participant.
  Intervention: Other: Shoulder resistive exercise

Inclusion Criteria:

• 18 years of age and older
• Present with clinical signs of subacromial impingement syndrome
• Have not yet initiated physical or occupational therapy treatment

Exclusion Criteria:

• Previous shoulder, cervical, or thoracic surgery.
• History of shoulder fracture, dislocation, labral tear, or full thickness rotator cuff tear
• Treatment for neoplasm in the last year
• Rheumatic disease
• Adhesive capsulitis
• Shoulder pain currently rated greater than or equal to 8/10 on the NPRS
• Cardiac, neurological, or musculoskeletal condition that precludes ability to perform upper extremity resisted exercise
• Pregnancy
• inability to understand spoken or written English
• Inability to arrange transport to evaluation or treatment sessions or not planning to stay in the area long enough to complete study