From Rest or Recoil: Comparing Squat and Countermovement Techniques for Maximum-Height Jumping Using Musculoskeletal Simulation and Dynamic Optimization—A Computational Study

Background: The countermovement jump (CMJ) and the squat jump (SJ) are two common techniques for maximum-height jumping. The CMJ typically produces a greater jump height than the SJ; however, the mechanisms responsible for this difference in performance and the roles that musculotendon dynamics play have been debated. Methods: We used musculoskeletal modelling and dynamic optimization to generate muscle-driven simulations of maximum-height jumping using the CMJ and SJ techniques. We modified an existing musculoskeletal model in OpenSim 4.4 with 18 lower-limb muscles and used single-shooting optimization to identify muscle excitation patterns that maximize jump height using each technique. Results: In our simulations, the CMJ produced a jump that was 18% higher than that produced by the SJ. Muscles generated 9% less positive mechanical work during the upward phase of the CMJ than during the SJ, but the positive mechanical work done by the tendons was 36% greater during the upward phase of the CMJ. Conclusions: This study provides insight into vertical jump performance, using musculoskeletal modelling and dynamic optimization to estimate variables that cannot be directly measured.