<![CDATA[Journal of Orthopaedic & Sports Physical Therapy - Jeffrey K. Kawaguchi, PT, ATC, PhD]]> http://www.jospt.org/jeffreykkawaguchi Wed, 30 Apr 2008 09:05:25 EST 0 Muscle Strength in the Lower Extremity Does Not Predict Postinstruction Improvements in the Landing Patterns of Female Athletes http://www.jospt.org/issues/articleID.1408/article_detail.asp Ryan L. Mizner, Jeffrey K. Kawaguchi, Terese L. Chmielewski

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

]]> http://www.jospt.org/issues/articleID.1408/article_detail.asp Effect of Patellar Taping on Knee Kinetics of Patients With Patellofemoral Pain Syndrome http://www.jospt.org/issues/articleID.530/article_detail.asp Gregory P. Ernst, Jeffrey K. Kawaguchi, Ethan Saliba
Study Design: Single-group repeated measures examining patients with patellofemoral pain syndrome. Objective: To examine the effect of McConnell patellar taping on single-leg vertical jump height and knee extensor moment and power during a vertical jump and lateral step-up. Background: Clinicians use patellar taping in an attempt to maximize knee extensor function during sporting activities and rehabilitation of patients with patellofemoral pain syndrome. No studies have examined the effect of patellar taping on vertical jump height and knee extensor moment and power during a maximal vertical jump or lateral step-up. Methods and Measures: Fourteen women (24.4 ± 5.8 years) with unilateral patellofemoral pain performed a single-leg vertical jump and lateral step-up during 4 knee conditions: patellar tape, placebo tape, no tape, and the uninvolved knee. Maximal knee extensor moment, knee power, and vertical jump height were measured for each condition using a force platform and motion analysis system. Results: Analyses of variance and post hoc analyses revealed a main effect for knee condition. The patellar tape condition resulted in a greater knee extensor moment (1.57 ± 0.32 N•m/kg) and power (3.47 ± 0.67 W/kg) than did the no-tape (1.31 ± 0.39 N•m/kg and 2.79 ± 1.21 W/kg) and placebo tape (1.33 ± 0.30 N•m/kg and 2.70 ± 0.99 W/kg) conditions. Additional analyses showed that the vertical-jump height was significantly greater in the uninvolved lower extremity (25.69 ± 2.66 cm) compared with the patellar tape (23.33 ± 4.22 cm), placebo tape (23.08 ± 4.20 cm), and no-tape (23.45 ± 4.54 cm) conditions. The patellar tape condition did not show a different vertical jump height than the placebo or no-tape conditions. Conclusions: These results suggest that patellar taping compared with no tape may improve the knee extensor moment and power during weight-bearing activities such as the lateral step-up exercise and the vertical jump. J Orthop Sports Phys Ther. 1999;29(11):661-667. Key Words: lower-extremity kinetics, patellar taping, patellofemoral pain]]> http://www.jospt.org/issues/articleID.530/article_detail.asp