Effect of Consecutive Jumping Trials on Metatarsophalangeal, Ankle, Knee and Hip Biomechanics During Take-Off and Landing: A Replication and Extension Study.

Replication is a fundamental aspect of scientific research, but few replications have been conducted within sports biomechanics yet. The aim of this study was to closely replicate Lam et al. (2021) study, investigating the differences of single and consecutive jump landing trials on ground reaction forces, metatarsophalangeal joint, ankle joint and knee joint kinematics and kinetics. We extended the analysis by including the hip joint biomechanics. Forty basketball players performed single and consecutive countermovement jumps (CMJ) tasks. Synchronised motion capture system and force plates were used to compute biomechanical variables during take-off and landing. Paired t-tests were performed to examine any significant effect of the task. The compatibility of the replication and original effect size estimates was evaluated with z-tests. The consecutive jumping task led to lower jump height, takeoff velocity and vertical ground reaction forces at landing for both studies. Unlike the original study, metatarsophalangeal joint, ankle joint, and knee joint velocities and powers were greater in single countermovement jump condition compared to consecutive condition. Additionally, the hip joint displayed larger velocities and power during take-off in the single CMJ condition compared to consecutive CMJ condition. The present study couldn't replicate most of the original findings, as the effect of consecutive jump on most of the joint kinematics and kinetics results was not consistent between the two studies. We recommend authors to describe the level of practice of their population and to adopt Open Science principles to build higher confidence in the sports sciences results.