The purposes of this study were to: a) measure peak torque (PKT) at 60 and 180°/sec of angular velocity and work data at 180°/sec of angular velocity for isokinetic muscular performance during external/internal rotation (ER/IR) and modified abduction/adduction (MOD-AB/AD) tests, b) compare the dominant and nondominant upper extremity data, and c) compare the relative peak torque between sexes. Twenty-one males and 20 females were tested isokinetically at 60 and 180°/sec in MOD-AB/AD and ER/IR. A significant difference did not exist between the dominant and nondominant shoulders for the PKT. A significant difference did exist between sexes when comparing PKT, total work, and power but not when comparing endurance and agonist/antagonist PKT and work ratios. The data described demonstrated large standard deviations suggesting the need for specific categorization of persons to establish normative values.

 J Orthop Sports Phys Ther 1989;10(7):264-269.

Posterior heel pain (PHP) presents a difficult clinical challenge. The causes of PHP include Haglund syndrome (pump bump deformity), Achilles tendinitis, and Sever's disease (retrocalcaneal bursitis, traction apophysitis). The purposes of this study were to 1) describe a new orthotic device used in the treatment of PHP and 2) evaluate the effectiveness of this device. The orthotic device consisted of a neoprene sleeve holding 1/4 inch PPT foam rubber horseshoe (Sports Supports, Inc., Dallas, TX). The horseshoe was placed directly over the injury to protect and relieve pressure or was inverted and used as a counterforce brace to reduce the tensile stress to the Achilles tendon. Eight patients (6 children, 2 adults) were evaluated at the time of application and after 1 month of use. Three criteria were considered: 1) subjective pain scale, 2) active goniometric measurements, and 3) toe raise test. The statistical analysis indicated a significant improvement in pain during activity from initial to follow-up and in pain after activity from initial to follow-up. All patients demonstrated improved strength and flexibility. It was concluded that this device may be an effective adjunct to the treatment of PHP.

 J Orthop Sports Phys Ther 1990;11(9):410-413.

STUDY DESIGN: Cross-sectional. OBJECTIVE: To determine if females presenting with patellofemoral pain syndrome (PFPS) from no discernable cause other than overuse demonstrate hip weakness and increased hip internal rotation, hip adduction, and knee valgus during stair descent. BACKGROUND: Historically, PFPS has been viewed exclusively as a knee problem. Recent findings have indicated an association between hip weakness and PFPS. Researchers have hypothesized that patients who demonstrate hip weakness would exhibit increased hip internal rotation, hip adduction, and knee valgus during functional activities. To date, researchers have not simultaneously examined hip and knee strength and kinematics in subjects with PFPS to make this determination. METHODS AND MEASURES: Eighteen females diagnosed with PFPS and 18 matched controls participated. Strength measures were taken for the hip external rotators and hip abductors. Hip and knee kinematics were collected as subjects completed a standardized stair-stepping task. Independent t tests were used to determine between-group differences in strength and kinematics during stair descent. RESULTS: Subjects with PFPS generated 24% less hip external rotator (P = .002) and 26% less hip abductor (P =. 006) torque. No between-group differences (P > .05) were found for average hip and knee transverse and frontal plane angles during stair descent. CONCLUSION: Subjects with PFPS had significant hip weakness but did not demonstrate altered hip and knee kinematics as previously theorized. Additional investigations are needed to better understand the association between hip weakness and PFPS etiology. LEVEL OF EVIDENCE: Symptom Prevalence, Level 4.

J Orthop Sports Phys Ther. 2008;38(1):12-18, published online 21 November 2007, doi:10.2519/jospt.2008.2462

KEY WORDS: anterior knee pain, hip abduction, hip external rotation, kinematics

Study Design: Repeated-measures experiment. Objective: To compare measures of end point accuracy (EPA) for 2 feedback conditions: (1) visual and kinesthetic feedback and (2) kinesthetic feedback alone, during shoulder movements, at 3 different speeds. Background: Shoulder joint kinesthesia is typically reported with EPA measures, such as constant error. Reporting multiple measures of EPA, such as variable error and absolute error, could provide a more detailed description of performance. Methods and Measures: Subjects were seated with the shoulder abducted 90° in the scapular plane and externally rotated 75°, with the forearm placed in a custom shoulder wheel. Subjects internally rotated the shoulder 27° to a target position at 48° of shoulder external rotation for both conditions. Motion analysis was used to determine peak angular velocity and 3 EPA measures for shoulder movements. Each EPA measure was compared between the 2 feedback conditions and among the 3 speeds with a separate 2-way analysis of variance. Results: Movements performed with kinesthetic feedback alone, measured by constant error (P<.01), variable error (P<.01), and absolute error (P<.01), were less accurate than movements performed with visual and kinesthetic feedback. Faster movements were less accurate when measured by constant error (P = .01) and absolute error (P<.01) than slower movements. Subjects tended to overshoot the target in the absence of visual feedback; however, movement speed played minimal role in the overshooting. Conclusions: Multiple measures of EPA, such as constant, variable, and absolute error during simple restricted shoulder movements may provide additional information regarding the evaluation of a motor performance or identify different central nervous system control mechanisms for joint kinesthesia.

J Orthop Sports Phys Ther. 2004;34(8):468-478. doi:10.2519/jospt.2004.1151 

Key Words: kinesthesia, proprioception, target accuracy, upper extremity

Study Design: Single-occasion, repeated-measures design. Objective: To determine the magnitude of hip abductor muscle activation during 6 rehabilitation exercises. Background: Many researchers have reported that hip strengthening, especially of the hip abductors, is an important component of a lower extremity rehabilitation program. Clinicians employ non–weight-bearing and weight-bearing exercise to strengthen the hip musculature; however, researchers have not examined relative differences in muscle activation during commonly used exercises. Information regarding these differences may provide clinicians with a scientific rationale needed for exercise prescription. Methods and Measures: Sixteen healthy subjects (mean ± SD age, 27 ± 5 years; range, 18-42 years; mean ± SD height, 1.7 ± 0.2 m; mean ± SD body mass, 76 ± 15 kg) volunteered for this study. Bipolar surface electrodes were applied to the right gluteus medius muscle. We measured muscle activation as subjects performed 3 non–weight-bearing (sidelying right hip abduction and standing right hip abduction with the hip at 0° and 20° of flexion) and 3 weight-bearing (left-sided pelvic drop and weight-bearing left hip abduction with the hips at 0° and 20° of flexion) exercises. Data were expressed as a percent of maximum voluntary isometric contraction of the right gluteus medius. Differences in muscle activation across exercises were determined using a 1-way analysis of variance with repeated measures, followed by a sequentially rejective Bonferroni post hoc analysis to identify differences between exercises. Results: The weight-bearing exercises demonstrated significantly greater EMG amplitudes (P<.001) than all non–weight-bearing exercises except non–weight-bearing sidelying hip abduction. Conclusion: The weight-bearing exercises and non–weight-bearing sidelying hip abduction exercise resulted in greater muscle activation because of the greater external torque applied to the hip abductor musculature. Although the non–weight-bearing standing hip abduction exercises required the least activation, they may benefit patients who cannot safely perform the weight-bearing or sidelying hip abduction exercises. Clinicians may use results from this study when designing hip rehabilitation programs.

J Orthop Sports Phys Ther. 2005;35(8):487-494. doi:10.2519/jospt.2005.2066

Key Words: gluteus medius, strengthening exercises, surface EMG

Study Design: Repeated-measures design comparing 7 static weight-bearing shoulder exercises. Objective:The purpose of this study was to determine the demand on shoulder musculature during weight-bearing exercises and the relationship between increasing weight-bearing posture and shoulder muscle activation. Background: Weight-bearing shoulder exercises are commonly prescribed in the rehabilitation of shoulder injuries. Limited information is available as to the demands placed on shoulder musculature while these exercises are performed. Methods: Eighteen healthy college students volunteered for this study. Surface bipolar electrodes were applied over the infraspinatus, posterior deltoid, anterior deltoid, and pectoralis major muscles. Fine-wire bipolar intramuscular electrodes were inserted into the supraspinatus muscle. Electromyographic (EMG) root mean square signal intensity was normalized to 1 second of EMG obtained with a maximal voluntary isometric contraction (MVIC). Subjects were tested under 7 isometric exercise positions that progressively increased upper extremity weight-bearing posture. Results: There was a high correlation between increasing weight-bearing posture and muscular activity (r = 0.97, p<0.01). There was relatively little demand on the shoulder musculature for the prayer and quadruped positions (2%-10% MVIC). Muscular activation was greater for the infraspinatus than for other shoulder muscles throughout most of the exercise positions tested. Conclusion: These results indicate that alterations of weight-bearing exercises, by varying the amount of arm support and force, resulted in very different demands on the shoulder musculature. Specifically, the infraspinatus was particularly active during the weight-bearing exercises used in this study.

J Ortho Sports Phys Ther. 2003;33:109-117.

Key Words: electromyography, muscles, progressive resistive exercise, rehabilitation