Sex and acute weighted vest differences in force production and joint work during countermovement vertical jumping

ABSTRACT

It is unclear whether weighted vest (WV) use improves countermovement vertical jump (CMVJ) performance by enhancing stretch-shortening cycle (SSC) function via increased storage and utilisation of elastic strain energy. In is also unknown whether WV use stimulates different responses in men and women. WV effects on energy storage and utilisation during CMVJ were examined in men and women. Nine men (25 ± 3 y; 89.7 ± 18.7 kg; 1.8 ± 0.1 m) and 12 women (24 ± 3 y; 62.7 ± 10.3 kg; 1.6 ± 0.1 m) performed CMVJ wearing a WV with (loaded) and without (unloaded) 10% added mass while kinematic and ground reaction force (GRF) data were obtained. A longer eccentric sub-phase and increased storage of elastic strain energy occurred when loaded. Increased positive joint work occurred during the concentric portion of loaded CMVJ. Women exhibited less positive hip work and greater positive ankle work than men during the unloading and eccentric sub-phases, respectively. Joint work was similar between sexes during the concentric sub-phase, likely due to decreased trunk extension excursion in men when loaded. Women and men employ different SSC strategies during the CMVJ, though the different strategies do not alter energy storage or concentric mechanical output.

KEYWORDS:

• Energy
• force production
• vertical jump
• weighted vest

Acknowledgments

The authors would like to thank all volunteers for participating in the study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was partially supported by a grant from the National Strength and Conditioning Association (NSCA) Foundation (2350-257-929M). The NSCA Foundation did not contribute to the study design, the collection, analysis, and interpretation of the data, the writing of the manuscript, or the decision to publish. The contents of this project are the sole responsibility of the authors and do not necessarily represent the views of the NSCA.