Effects of stiffness-altered compression garments on lower-limb angular kinematics and force-time characteristics in countermovement jumps

Background: Compression garments (CGs) with localized stiffness alterations are marketed to enhance athletic performance, yet evidence for benefits in jumping remains limited. This study aimed to evaluate the effects of stiffness-altered CGs on lower-limb angular kinematics and force-time characteristics in countermovement jumps (CMJs). Methods: 62 physically active adults (31 female, 31 male) performed CMJs under four conditions: control (shorts only), knee sleeves with stiffness components, compression leggings without stiffness alterations, and stiffness-altered compression leggings. Sagittal-plane angles were recorded via motion capture, and vertical ground reaction forces via force platforms. Two-way (sex*condition) ANOVA were performed for derived variables, employing both discrete and one-dimensional statistical parametric mapping (SPM) analyses. No sex-by-condition interactions were observed. No significant differences were found between the two non-leggings conditions, nor between the two leggings conditions. Conclusion: Despite no detectable performance decline, compression leggings primarily restricted hip motion and altered eccentric phase characteristics in CMJs, likely diminishing stretch-shortening cycle efficiency. To promote beneficial effects of stiffness-altered CGs, future study designs shall control for garment fitting via compression and stiffness measurements, as well as individual variations in skill levels via more specific and representative sampling.