COMPARISON OF ISOKINETIC MUSCLE PERFORMANCE IN ACTIVE, HEALTHY MALES AND FEMALES Brett Wright, Halli Meyer, Rhonda Cross Beemer, PhD, ATC, (Mentor) Pharmaceutical, Biomedical, & Administrative Sciences Department; College of Pharmacy & Health Sciences Pearson correlation coefficient was computed to assess the relationship between body weight, height, and BMI among genders. Results Descriptive statistics were calculated for total subjects’ height, weight, and BMI. 9 females (mean ±SD; height,66.89±2.89, body wt,145.99±17.54, BMI22.73±2.09) and 8 males (height 72.38±2.26, body wt ±55.01, BMI 28.4±5.62) There were significance differences across all 3 sets found for concentric and eccentric peak torques (p=.05) when comparing the genders. Females: There were multiple positive correlations. Most notable at p <0.01 were between height and PkTq Con Quad (r-0.810, n=9, p<.01), body weight and PkTq Con Hip ABD (r=.935, n=9, P<0.01) Males: There were multiple positive correlations. Most notable at p<0.01 were between BMI and PkTq Con Hip ER (r=0.870, n=8, p<0.01), height and PkTq Con Hip ER (r=0.852, n=8, p<0.01), body weight and PkTq Con Hip ER (r=0.921, n=8, p<0.01), BMI and PkTq Ecc Ham (r=0.934, n=8, p<0.01) and body weight and PkTq Ecc Ham (r=0.922, n=8, p<0.01). Overall, in females set 3 if there was an increase in height, there was in increase in PkTq Con Quad. An increase in body weight showed an increase in PkTq Con Hip Abduction. Overall, in males, an increase in BMI showed an increase in PkTq for Con Hip ER and Ecc Ham. An increase in height showed an increase in PkTq Con Hip ER. An increase in weight showed an increase in PkTq Ecc Ham. Conclusion Hypothesis: Peak torque values in females will be less when compared to males. Based on that data analysis, it would appear that males do have a greater peak torque in all actions when compared to women both concentrically and eccentrically. Furthermore, there seems to be positive correlations in both male and female groups when among body weight, height, and BMI and certain actions. The higher the weight, height, and BMI the greater some values are in gender. Limitation: All strength tests were done in an isokinetic setting at 30 o /s, which is not sport specific. This study identifies key muscle groups that should be assessed when evaluating patients with knee pain. Abstract The purpose of this study was to examine lower extremity muscle performance differences and relationships in active, healthy males and females to determine attributes that increase risk of developing knee injuries, such as patellofemoral pain syndrome (PFPS). Previous research has shown that deficits in certain muscle groups may lead to faulty kinematics that can attribute to higher risk of developing knee pain and injury. Gender differences have been observed that may lead to the higher incidence of knee injuries in females. It was hypothesized that peak torque values in all females will be less when compared to males. Subjects were recruited in this IRB approved study. Subjects (n=17) underwent a series of muscle performance tests using the Biodex System 4 Isokinetic Dynamometer. Actions performed in this study included knee extension and flexion, hip external rotation, and hip abduction in concentric and eccentric isokinetic testing mode. Results: Independent sample T Tests indicated that males exhibited an increase in peak torque for all testing conducted. Pearson correlations indicate that there are positive relationships between body weight, BMI, and concentric and eccentric peak torques in both genders. Introduction Previous studies have shown that there are correlations between hip and knee strength, functional ability, and subjects with PFPS 1. Weak hip abductors and lateral rotator muscles have been associated with excessive femoral adduction and femur medial rotation 2. Studies also suggest that people with PFPS may have weaker knee extensors, hip extensors, and hip rotator strength compared to subjects without PFPS 3. Women showed greater correlation coefficients between eccentric hip abductor torque and coronal plane femur and knee movements than men 4. Subjects with PFPS exhibit greater hip adduction than controls. Women in general have shown similar abnormal lower-extremity kinematics when compared to male. Counterparts 4. Studies have shown that females have lower eccentric KF/KE peak torque ratios when compared to males 4. Therefore, the purpose of this study was to evaluate peak torques between males and females. It was hypothesized that peak torque values in females will be less when compared to males. Methods This study was approved by Drake University IRB. Recruitment of subjects was conducted using , word-of- mouth, and printed flyers. All research took place in the Ellis Disease Prevention Lab at Drake University Subjects completed the Anterior Knee Pain Scale, visual analogue pain scales with activities known to cause knee pain, and a visual analogue scale of current pain levels, followed by a brief warm-up and stretching period (exclusion criteria). Actions performed were knee extension, knee flexion, hip external rotation, and hip abduction in both concentric and eccentric isokinetic mode using the Biodex Isokinetic Dynamometer System Pro. See Fig 1, 2, & 3 for example actions. Torque limits were set at 25% of subjects’ body weight. References 1. Nakagaw, T., Baldon, R., Muniz, T., Serrao, F., Relationship among eccentric hip and knee torque, symptom severity and functional capacity in females with patellofemoral pain syndrome. Physical therapy in sport. 12, Jacobs, C.A., Uhl, T.L., Mattacola, C.G., Shapiro, R., & Rayens, W.S. (2007). Hip abductor function and lower extremity landing kinematics: Sex differences. Journal of Athletic Training, 42, 76–83. 3.Souza, R.B., Powers, C.M., 2009b. Predictors of hip internal rotation during running: an evaluation of hip strength and femoral structure in women with and without patellofemoral pain. Am. J. Sports Med. 37, Baldon, R.M., Lobato, D.F., Serrao, F.V., Differences between genders in eccentric hip adduction to abduction, hip medial to lateral rotation and knee flexion to extension peak torque ratios. Isokinetics and Exercise Science. 19, Acknowledgements We would like to acknowledge all participants who gave up their time to be in our study, Gary Williamson for his expertise, the Administrative Sciences faculty for SPSS assistance, and Dr. Rhonda Cross Beemer for being an outstanding mentor. Fig. 1: 30 o of hip abduction Fig. 2: 70 o of knee extensionFig. 3: 20 o of hip external rotation Fig. 4: Peak torque concentric vs eccentric mean values for gender Statistical analyses were performed using SPSS statistical software and Microsoft Excel Descriptive statics were calculated for total subjects’ height, weight, and BMI Independent Sample T Tests were completed for each set to compare differences between genders in all exercises (Fig. 4)