The role of starting knee angle in squat jump force-velocity profiles: interactions with subjects’ strength levels and imputed push-off distance
Year: 2025
Type: article
Abstract: Introduction This study investigated whether differences in the force-velocity (F-v) profile obtained using Samozino’s method during squat jumps (SJ) performed at varying knee angles are influenced by subjects’ strength levels and the push-off distance (HpO) used in the analysis. Methods Twenty-one resistance-trained men were classified as stronger (n = 10) or weaker (n = 11) based on the external load required to achieve a 10 cm SJ height. F-v profiles were randomly assessed over three sessions, with SJs performed at starting knee angles of 70° (SJ70), 90° (SJ90), and 110° (SJ110), using either the actual HpO specific to each condition or a standardized HpO corresponding to SJ90. Results Significant differences between SJ types were observed for maximum force (F0) and the F-v slope (SJ110 > SJ90 > SJ70). These differences were never influenced by subjects’ strength levels. The standardized HpO produced similar outcomes for maximum power (Pmax) and maximum velocity (v0), and more consistent results for F0 and the F-v slope compared to the actual HpO. Discussion Regardless of strength levels, standardizing HpO at 90° and allowing subjects to select a starting knee angle between 70° and 90° could simplify the evaluation process and improve the comparability of F-v profiles across subjects when using Samozino’s method.
Source: Frontiers in Physiology
Authors: Xuelin Qin, Beibei Liu, Ruolin Tang, Yan Liu, Amador García-Ramos
Language: English
Subfield: Orthopedics and Sports Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W4407419528