Patellofemoral joint stress and vertical loading rates during forefoot striking, increasing step rate, and forward trunk lean running

Abstract

The number of runners has increased over the world in recent years. Every year, up to 70% of runners related some musculoskeletal injury. It is known that a half of injuries that occur as a result of this activity involve the knee joint and, Patellofemoral Pain (PFP) is the most common injury. Recently, some running technique modifications (landing with the forefoot on the ground, increasing 10% of the step rate (steps/minute) and increasing the forward trunk lean) showed potential to reduce the vertical impact loading rates, the demand on the knee joint and the patellofemoral joint stress (PFJS). However, no study had evaluated these effects during the same protocol. Our purpose is to analyze the immediate effects of these techniques in vertical impact peak, average vertical loading rate, knee extensor moment, knee adduction moment, hip abduction moment and PFJS in healthy runners. The techniques will be evaluated at a random order on an instrumented treadmill (Bertec, Columbus, OH, USA). For data analysis, multivariate analysis of variance (MANOVA) with repeated measures will be used to compare running conditions. A significance level of 5% will be considered for all comparisons. It is important to investigate the effects of different running techniques on lower limb biomechanics in order to improve injury prevention and rehabilitation programs. (AU)