Temporal analysis of cellular and molecular response-driven ground reaction forces in predicting volleyball spike jump height: Insight for optimizing spike jump performance

Ground reaction force (GRF) during jumping, which is an outcome of the complex cellular and molecular biomechanical processes within the lower limb, reflects the interaction of the lower limb with the ground. Previous studies, however, have been restricted to analyzing only the peak kinetics, overlooking the moment when the peak occurs and other essential details beyond the peak. Thus, the objective of our study was to explore the relationship between the full time series of GRF and jump height during volleyball spike jumps, considering the underlying cellular and molecular biomechanical mechanisms. Data on the kinematics and kinetics of 22 elite male (mean age: 21.56 years) collegiate volleyball players’ spike jumps were gathered via a motion capture system comprising 13 high-speed cameras and 2 force plates. Then, we analyzed the association between the full ground reaction force time series and jump height using statistical parameter mapping (SPM) regression. The results of the study demonstrated that the horizontal GRF of the dominant foot was significantly related to jump height in the 23%–80% interval of dominant foot contact (DFC) with the force plate to takeoff (TO). This association is likely due to the coordinated activation and contraction of specific muscle cells and molecular signaling pathways within the lower limb muscles that govern force generation and transmission. The vertical GRF of the dominant foot was significantly associated with jump height in the 29%–35% and 80%–94% intervals of DFC to TO, which could be attributed to the differential recruitment and activity of muscle fibers at the cellular and molecular levels. Similarly, the non-dominant foot was significantly associated with jump height in the 48%–63% interval of non-dominant foot contact (NFC) with the force plate to TO. These data emphasize the significance of enhancing lower limb muscle capacity through interventions that target the cellular and molecular biomechanical aspects, in order to improve jumping technique and overall performance. Copyright © 2024 by author(s).