Bilateral vs. Unilateral Vertical Jump


Ellen Ayers and Alexia Patrick

Kinesiology & Health Science, Stephen F. Austin State University

Mentor: Amber Chelette, amber.chelette@sfasu.edu

This study aimed to compare the force production of the right and left leg in unilateral and bilateral jumps. We hypothesized that the dominant leg would produce more force in a unilateral and bilateral vertical jump. After gathering seven dancers (one man, and six women) we first had to determine our subject's dominant leg. We performed a simple test dominance where we lightly nudged our subjects from behind and their dominant leg would step forward to catch themselves naturally. We found that four of our subjects are right dominant and three are left dominant.

After we recorded their dominant leg we began our procedures with the Kinvent Delta Force Plate. We started testing force from a unilateral vertical jump by having our participants stand on their left leg on the force plate with their right leg bent at a 90-degree angle and arms down by side. We allowed participants to perform a counter-movement before each vertical jump where they would bend their left knee and swing their arms back for momentum and then vertical jump. The participant then landed back on the left leg and we proceeded to have them repeat this on the opposite side. Our subjects rested for five seconds before moving on to the bilateral vertical jump, where they would then stand on the force plate with both legs and perform a vertical jump landing on both legs.

The results showed that the average force was 22.325 for the right dominant on the right, 19.93 for the left dominant on the right, 21.275 for the right dominant on the left, and 19.6 for the left dominant on the left. The standard deviation for the bilateral vertical jump was 7.343, 3.97 for the unilateral right leg vertical jump, and 3.39 for the unilateral left leg vertical jump. Our results did not support the hypothesis because the force production was greater from the right leg in the unilateral vertical jumps for both left and right dominant subjects.

This study was limited by a small sample size and difficulty finding left-dominant subjects. With a bigger sample size, the standard deviation of force production would be lower and give us more accurate results to compare left vs. right dominant subjects. Future studies should include different groups of subjects based on their respective sports, and compare the data of each sport to one another to see if there are any similarities and differences between different kinds of athletes' force production from dominant and non-dominant.

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