THE EFFECT OF SQUAT DEPTH ON MUSCLE ACTIVATION IN MALE AND FEMALE CROSS-COUNTRY RUNNERS

Abstract

The squat is a closed-chain lower body exercise that is regularly performed by many athletes. The squat has been shown to increase strength of the rectus femoris, biceps femoris, gastrocnemius (Isear et al., 1997) and erector spinae (Nuzzo et al., 2008). Squats of different depths have been shown to alter muscle activation in male weight lifters (Caterisano et al., 2002), but the findings may not be directly applicable to runners. Therefore, we chose to examine both male and female runners and and multiarticular muscles that often fatigue while running. Muscle activation during parallel and partial squats has not been examined in runners. Hanon et al. (2002) reported that the rectus femoris and biceps femoris are among the first muscles to fatigue in runners. The gastrocnemius becomes increasingly important for running uphill (Sloniger et al., 1997), and the lumbar erector spinae can help runners to maintain upright posture and decrease the risk of injury to the hamstrings (Hoskins & Pollard, 2005). The purpose of this study was to determine the effect of squat depth on muscle activation in both male and female collegiate cross-country runners. This may help athletes and coaches to determine which squat depth is most effective. We hypothesized that the parallel squat would increase extensor muscle activity (i.e. hamstrings and erector spinae). Furthermore, we sought to determine if changes in muscle activity were different between males and females.