Comparison of eccentric isokinetic torque of the knee, hip and ankle between individuals with and without patellar tendinopathy

Abstract

Patellar tendinopathy (PT) is an overuse injury characterized by anterior knee pain related to physical activity, mostly activities with jump landings. The high prevalence of this injury in athletes may be related to the strategy used by them during landing. For example, the preferential use of the quadriceps to absorb the high-impact forces that act on the lower limb during landings and an eccentric deficit in the hip extensors and ankle plantar flexors may excessively overload the patellar tendon. Nevertheless, there are no studies evaluating the torque in these muscles in this population. Therefore, the purposes of this study are to evaluate the eccentric torque of the hip extensors, knee extensors and ankle plantar flexors and the ratios knee torque/hip torque and knee torque /ankle torque. Individuals with age between 18 and 30 years will participate in this study. They will be divided into 2 groups: individuals with PT and control. The sample size will be determined based on a pilot study, considering an 80% statistic power and a statistical significance of 5%. The eccentric torque will be measured with a Biodex Multi-Joint System III isokinetic dynamometer. Evaluations will be conducted in a velocity of 60 deg/sec. The mean peak torques normalized by the body mass will be compared between groups using a multivariate analysis of variance (MANOVA). In the presence of significant multivariate effects the univariate effects will be analyzed. For all analyses a significance level of 5% will be considered. (AU)