Ankle dorsiflexion effect on maximal vertical jump performance


Vertical jump is the action of propelling the body vertically into the air. It is used to assess athletic performance. During this movement, the ankle, knee, and hip exhibit flexion during the countermovement – squat portion – to maximize vertical force produced. The purpose of this study was to test whether dorsiflexion of the ankle during the counter movement of a vertical jump affects maximum jump height performance. We hypothesized that the joint angle would affect performance. To test this, we recruited eight current and former athletes between the age of 20 -22 years old. Each participants was asked to perform three jumps each. The first jump consisted of MINIMAL ankle dorsiflexion during the counter movement. For the second jump, participants were instructed to perform a NORMAL counter movement. Finally, participants were asked to perform a DEEP squat jump with maximum dorsiflexion during their counter movement. Participants performed all jumps on a Just Jump Mat in order to obtain data for the height of their jump. Every jump was video recorded from an iphone11 and transferred over to Dartfish ® to measure the angle of ankle flexion during each countermovement. Ankle range of motion and jump height were averaged between subjects. Pearson’s correlation was performed to determine the relationship of jump height and ankle range of motion. The NORMAL jump height averaged 22.6 inches and ankle dorsiflexion was 18.58°. The DEEP jump exhibited the greatest ankle dorsiflexion (20.62°) and a jump height of 21.25 inches. The MINIMAL jump had the least ankle dorsiflexion (15.19°) and the lowest jump height of 12.95 inches. Overall, there was a negative correlation between jump height and ankle ROM (r = -.52). Greater ankle dorsiflexion was generally associated with a lower jump height. The correlation between jump height and ankle dorsiflexion was strongest for the NORMAL jump condition (r=-.64) and weakest for the MINIMAL jump condition (r=-.21). Overall, it was determined that ankle dorsiflexion does impact vertical jump performance. The findings were limited by a small sample size and population. Since participants were college aged, current, or formal athletes so the results may not apply to the general or older populations.

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