Correlation Between Varying Back Squat Depths On Speed And Vertical Jump Performance In North American High School Football Players

The back squat exercise is perhaps the most popular and most effective exercise for developing lower body musculature. Development of the lower body musculature is paramount for increasing ground reaction forces which in turn can translate to increased explosiveness in movements such as sprinting or vertical jumping (VJ). For athletes in particular, developing lower body strength can be of utmost importance. There is however dispute over which back squat depth is most optimal. PURPOSE: This study attempted to determine which of two back squat depths (90 degree knee flexion or 45 degree knee flexion) would correlate with superior sprint times and VJ performance. METHODS: Participants were high school aged males on a North American football team (age: 15.1±0.9 yrs, mass: 77.0±13.2 kgs). Twenty three athletes performed the 36.6 meter (36.6M) sprint and VJ tests along with performing a 3RM back squat at 90 and 45 degrees of knee flexion on randomized separate days. A Pearson Correlation Coefficient (r) test was used to compare the squat scores with sprint times and VJ performance. RESULTS: Variable measures were 36.6M: 5.23±0.26 secs, VJ: 59.6±6.6 cms, 90° 3RM squat: 116.1±21.0 kgs, and 45° 3RM squat: 132.1.±22.2 kgs. Low correlations were found at both knee flexion angles: 90° 3RM squat (36.6Mr=-0.32, VJr=0.33, p<0.01), and 45° 3RM squat (36.6Mr=-0.31, VJr=0.33, p<0.01). However, moderate correlations were revealed when comparing the 3RM back squat/body mass ratio with the participant’s 36.6M sprint times (90r=-0.46, 45r=-0.46, p<0.01). CONCLUSIONS: Within the parameters of this study, low to moderate correlations were determined between back squat strength and sprint speed as well as VJ at both 90 and 45 degrees of knee flexion.