COMPARISON OF ISOMETRIC, CONCENTRIC AND ECCENTRIC PEAK KNEE FLEXOR TORQUE AND RATE OF TORQUE DEVELOPMENT BETWEEN WOMEN WITH AND WITHOUT PATELLOFEMORAL PAIN

Abstract

Patellofemoral pain (PFP) is a common and costly musculoskeletal disorder that encompasses men, women and adolescents. Muscles such as the hamstring can influence knee and patellofemoral joint mechanics during functional activities. In fact, experimental studies have shown that hamstrings loading contributes to lateral patellofemoral malalignment and elevated cartilage pressure, main contributors to PFP. However, it remains unknown whether women with PFP present with altered hamstring muscle strength. To date, no study has been performed investigating knee flexor peak torque and rate of torque development, both variables important in functional and sport activities. Therefore, the aim of this study is to compare isometric, concentric and eccentric peak knee flexor torque and rate of torque development between women with and without PFP. Twenty-four women with PFP and twenty-four asymptomatic controls will be recruited to participate in the study. Isometric, concentric, and eccentric knee flexor torque will be assessed using an isokinetic dynamometer. Rate of torque development will be calculated as the change in torque over the change in time from torque onset to 30%, 60%, and 90% of the maximal torque during isometric, concentric, and eccentric contractions. Peak knee flexor torque will be considered the maximum value. Isometric/concentric/eccentric maximal torque, and rate of torque development variables of knee flexors will be compared between groups using independent t-tests and effect sizes will also be calculated.