Associations between jumping ability and isokinetic strength of the trunk and lower limb extensors: analysis of countermovement jump and rebound drop jump trials

• Published in: Journal of Physical Education and Sport 2024-01, Vol.24 (1), p.149-158
• Main Authors: Shimizu, Yutaka, Shinobu, Yamamoto, Nishimura, Saburo, Numazu, Naoki
• Format: Article
• Language: English
• Subjects: Ankle; College Students; Correlation; Exercise; Females; Investigations; Jumping; Knee; Males; Muscle strength; Muscular Strength; Physical Fitness; Scientific Concepts; Team Sports; Track & field; Track and Field; University students; Volleyball
• ISSN: 2247-8051; 2247-806X
• DOI: 10.7752/jpes.2024.01019

This study aimed to establish a correlation between jumping ability and the isokinetic strength of the trunk and lower limb extensors in female university athletes and to provide recommendations for improving jumping ability. Participants were 26 female university students from the track and field and volleyball teams. They performed a countermovement jump (CMJ) and a 30-cm rebound drop jump (RDJ). The following parameters were measured using high-speed video motion analysis: contact time, jump height, RDJ-index, joint angles, and joint angular velocities of the knee and ankle joints during the CMJ and RDJ. Additionally, the peak torques of the trunk and lower limb extensors and the percentage of total torque of three lower limb joints were measured using an isokinetic dynamometer. Based on the mean RDJ-index, the participants were classified into two groups: those with an RDJ-index of 0.80 m/s or higher (HG; n=12) and those with a lower RDJ-index of less than 0.80 m/s (LG; n=14). Our study yielded the following findings. The HG exhibited significantly greater heights in CMJ and RDJ, along with a higher RDJ-index and a notably shorter contact time compared with the LG. In the RDJ, the HG demonstrated significantly higher maximum knee flexion and ankle dorsiflexion angles compared with the LG. The HG tended to display significantly higher peak ankle plantar flexion and peak hip extension torques compared with the LG. Maximum knee flexion and ankle dorsiflexion angles exhibited significant negative correlations with RDJ contact time and positive correlations with RDJ-index. Significant positive correlations were observed between RDJ jump height and peak trunk extension torque as well as between RDJ-index and peak hip extension torque. These findings suggest that the low RDJ-index group can improve jumping performance by utilizing ankle plantar flexor muscle strength to achieve the jump with less contact time and by enhancing the isokinetic muscle strength of the trunk and hip extensors in order to stabilize the upper body and contribute to the acquisition of jump height.