Muscle Size and Power: Associations Between Vastus Lateralis and Rectus Femoris CSA and Countermovement Jump Performance in Snatch Practitioners

This study aimed to examine the individual and combined associations of the cross-sectional areas (CSA) of the vastus lateralis (VL) and rectus femoris (RF) with countermovement jump (CMJ) height in snatch practitioners. Nineteen young adult recreational snatch practitioners (28.1 ± 3.6 years) with at least one year of uninterrupted training participated in this cross-sectional study. Two experimental sessions were conducted: CMJ familiarization and, seven days later, panoramic ultrasound assessment of VL and RF CSA followed by CMJ testing. CSA was measured at 50% femur length using B-mode ultrasound, and CMJ height was assessed using the MyJump2 application. Simple and multiple linear regression analyses were performed (α ≤ 0.05). VL CSA significantly predicted CMJ height (B = 0.639, β = 0.641, R 2 = 0.411, p=0.003), whereas RF CSA showed a positive but non-significant association (B = 1.747, β = 0.449, R 2 = 0.202, p=0.054). The combined CSA (VL + RF) was also significantly associated with CMJ height (B = 0.578, β = 0.662, R 2 = 0.438, p=0.002). However, in the multiple regression model (R 2 = 0.440, F(2,16) = 6.285, p=0.010), only VL CSA remained an independent predictor (β = 0.551, p=0.019), while RF did not contribute independently (p = 0.374). These findings indicate that vastus lateralis morphology is the primary muscle-specific correlate of CMJ performance in snatch practitioners, highlighting its relevance for explosive lower-limb performance in Olympic weightlifting contexts.