STUDY DESIGN: Cross-sectional. OBJECTIVES: To measure fear of movement/re-injury levels and determine the association with function at different timeframes during anterior cruciate ligament (ACL) reconstruction rehabilitation. We hypothesized that fear of movement/re-injury would decrease during rehabilitation and be inversely related with function. BACKGROUND: Fear of movement/re-injury can prevent return to sports after ACL reconstruction, but it has not been studied during rehabilitation. METHODS AND MEASURES: Demographic data and responses on the shortened version of Tampa Scale for Kinesiophobia (TSK-11), 8-Item Short-Form Health Survey (SF-8), and International Knee Documentation Committee (IKDC) subjective form were extracted from a clinical database for 97 patients in the first year after ACL reconstruction. Three groups were formed (Group 1: £ 90 days, Group 2: 91 to 180 days, Group 3: 181 to 372 days post ACL reconstruction). Group differences in TSK-11 score, SF-8 bodily pain rating, and IKDC scores were determined. Hierarchical linear regression models were created for each group with IKDC score as the dependent variable and demographic factors, SF-8 bodily pain rating, and TSK-11 score as independent variables. RESULTS: TSK-11 score was higher in Group 1 than Group 3 (p < 0.05). Across the groups, SF-8 bodily pain rating decreased (p < 0.001) and IKDC score increased (p < 0.001). SF-8 bodily pain rating was a significant factor in the regression model for all groups, whereas TSK-11 score only contributed to the regression model in Group 3 (partial correlation -.529). CONCLUSIONS: Pain was consistently associated with function across the timeframes studied.  Fear of movement/re-injury levels appear to decrease during ACL reconstruction rehabilitation and are associated with function in the timeframe when patients return to sports. LEVEL OF EVIDENCE: Therapy, level 3a.

J Orthop Sports Phys Ther., Epub 19 September 2008. doi:10.2519/jospt.2008.2887

KEY WORDS: ACL, knee injury, psychosocial, outcomes

STUDY DESIGN: Preinstruction and postinstruction testing in a laboratory setting. OBJECTIVES: To examine the predictive relationship between lower extremity muscle strength and the immediate postinstruction changes in landing patterns of female athletes. We hypothesized that greater strength would be associated with larger postinstruction improvements in landing patterns. BACKGROUND: Female athletes in high-demand sports may be predisposed to anterior cruciate ligament injury because of poor landing patterns. Instruction has been shown to improve landing patterns. Lower extremity muscular strength may determine the potential for instruction to alter landing patterns. METHODS AND MEASURES: Thirty-seven female collegiate athletes in high-demand sports participated. Strength was assessed in the following muscle groups: trunk extensors and flexors, hip abductors and extensors, knee flexors and extensors, and ankle plantar flexors. Strength testing was followed by kinetic and kinematic analysis of a drop vertical jump task. Athletes then received verbal instruction on how to improve their landing technique and were retested. Landing variables of interest were force absorption time, peak vertical ground reaction force (vGRF), peak knee flexion and abduction angle, and peak external knee abduction moment. Preinstruction and postinstruction landing variables data were compared. Linear regression models were created with strength values as independent variables and landing variables as dependent variables. RESULTS: After instruction, athletes significantly increased their force absorption time and peak knee flexion angle, while decreasing their peak vGRF, peak knee abduction angle, and peak external knee abduction moment (P<.001). None of the regression models were statistically significant (P>.05). CONCLUSIONS: A brief instructional session promotes short-term improvements in the landing patterns of collegiate female athletes, but muscular strength was a poor predictor of the improvements. LEVEL OF EVIDENCE: Prognosis, level 4.

J Orthop Sports Phys Ther. 2008;38(6):353-361, published online 10 April 2008. doi:10.2519/jospt.2008.2726

KEY WORDS: ACL, biomechanics, hip, knee, motion analysis

STUDY DESIGN: Nonexperimental. OBJECTIVES: To determine interrater and intrarater agreement for 2 methods of evaluating movement quality during 2 lower extremity func­tional tasks, and to descriptively compare levels of agreement between the 2 methods. BACKGROUND: Clinicians typically use observational analysis to evaluate movement quality during functional tasks, but the extent of agreement is unknown. METHODS AND MEASURES: Twenty-five uninjured subjects performed 3 trials of unilateral squat and lateral step-down tasks. Three clinicians evaluated the trunk, pelvis, and hips for coronal plane and transverse plane movement deviations. Two rating methods were used: assessment of the entire movement (“overall method”) and rating each segment individually (“specific method”). Movement deviation severity was rated using basic clinical guidelines and ratings were repeated from videotape. Percent agreement and weighted kappa coefficients were calculated between rater pairs and rating sessions. Generalized kappa coefficients were calculated across raters. RESULTS: Interrater and intrarater percent agreement were higher using the overall method. Interrater weighted kappa coefficients were similar between rating methods (overall method, 0-0.55; specific method, 0.23-0.53). Intrarater weighted kappa coefficients were higher for the specific method (0.38-0.68) compared to the overall method (0.13-0.50). Generalized kappa coefficients were also higher for specific method compared to the overall method (unilateral squat, 0.19 and 0.01, respectively; lateral step-down, 0.22 and 0.18, respectively) and 95% confidence intervals remained above zero. CONCLUSIONS: Rating movement at body segments appears to result in agreement among raters that is better than chance. Neither rating method produced high agreement, indicating a need to develop more explicit criteria for rating movement deviation severity.  

J Orthop Sports Phys Ther. 2007;37(3):122-129. doi:10.2519/jospt.2007.2457 

KEY WORDS: functional testing, hip, knee, movement analysis, neuromuscular, reliability

Study Design: Prospective single-group repeated-measures design. Objectives: To quantify electromyographic (EMG) muscle activity of the infraspinatus, teres minor, supraspinatus, posterior deltoid, and middle deltoid during exercises commonly used to strengthen the shoulder external rotators. Background: Exercises to strengthen the external rotators are commonly prescribed in rehabilitation, but the amount of EMG activity of the infraspinatus, teres minor, supraspinatus, and deltoid during these exercises has not been thoroughly studied to determine which exercises would be most effective to achieve strength gains. Methods and Measures: EMG measured using intramuscular electrodes were analyzed in 10 healthy subjects during 7 shoulder exercises: prone horizontal abduction at 100° of abduction and full external rotation (ER), prone ER at 90° of abduction, standing ER at 90° of abduction, standing ER in the scapular plane (45° abduction, 30° horizontal adduction), standing ER at 0° of abduction, standing ER at 0° of abduction with a towel roll, and sidelying ER at 0° of abduction. The peak percentage of maximal voluntary isometric contraction (MVIC) for each muscle was compared among exercises using a 1-way repeated-measures analysis of variance (P<.05). Results: EMG activity varied significantly among the 7 exercises. Sidelying ER produced the greatest amount of EMG activity for the infraspinatus (62% MVIC) and teres minor (67% MVIC). The greatest amount of activity of the supraspinatus (82% MVIC), middle deltoid (87% MVIC), and posterior deltoid (88% MVIC) was observed during prone horizontal abduction at 100° with full ER. Conclusions: Results from this study provide initial information to develop rehabilitation programs. It also provides information helpful for the design and conduct of future studies.

J Orthop Sports Phys Ther. 2004;34(7):385-394. doi:10.2519/jospt.2004.0665 

Key Words: dynamic stabilization, infraspinatus, supraspinatus, teres minor

We will discuss the mechanisms by which dynamic knee stability may be achieved and relate this to issues that interest clinicians and scientists concerned with dynamic knee stability. Emphasis is placed on the neurophysiologic evidence and theory related to neuromuscular control. Specific topics discussed include the ensemble firing of peripheral mechanoreceptors, the potential for muscle stiffness modulation via force and length feedback, postural control synergies, motor programs, and the neural control of gait. Factors related to answering the difficult question of whether or not knee ligament injuries can be prevented during athletic activities are discussed. Prevention programs that train athletes to perform their sport skills in a safe fashion are put forth as the most promising prospect for injury prevention. Methods of assessing neuromuscular function are reviewed critically and the need for future research in this area is emphasized. We conclude with a brief review of the literature regarding neuromuscular training programs.

J Orthop Sports Phys Ther. 2001;31(10):546-566.

Key Words: knee, stability

Plyometric exercise was initially utilized to enhance sport performance and is more recently being used in the rehabilitation of injured athletes to help in the preparation for a return to sport participation. The identifying feature of plyometric exercise is a lengthening of the muscle-tendon unit followed directly by shortening (stretch-shortening cycle). Numerous plyometric exercises with varied difficulty and demand on the musculoskeletal system can be implemented in rehabilitation. Plyometric exercises are initiated at a lower intensity and progressed to more difficult, higher intensity levels. The progression to higher-intensity plyometric exercise is thought to resolve postinjury neuromuscular impairments and to prepare the musculoskeletal system for rapid movements and high forces that may be similar to the demands imposed during sport participation, thus assisting the athlete with a return to full function.

While there is a large body of scientific literature that supports the use of plyometric exercise to enhance athletic performance, evidence is sparse regarding the effectiveness of plyometric exercise in promoting a quick and safe return to sport after injury. This review will describe the mechanisms involved in plyometric exercise, discuss the considerations for implementing plyometric exercise into rehabilitation protocols, examine the evidence supporting the use of plyometric exercises, and make recommendations for future research. J Orthop Sports Phys Ther. 2006;36(5):308-319. doi:10.2519/ jospt.2006.2013

Key Words: jump training, neuromuscular, return to sport, stretch shortening