Biomechanical analysis of the pull in the snatch phase of weightlifting

Abstract

In the weightlifting snatch event, lifting efficiency depends on the optimal transfer of mechanical energy through the kinematic chain. Slight alterations during the pull phase degrade power production and compromise the barbell catch. The general objective of this research was to characterize, based on international scientific evidence and kinematic diagnosis, the biomechanical factors that influence the execution of the pulls during the snatch phase in high-performance weightlifting. A quantitative, descriptive-correlational, and cross-sectional study was conducted with N = 12 male youth weightlifters. Data collection combined 2D videogrammetry at 120 fps using Kinovea software and linear measurement via a Chronojump optical encoder. The results revealed a reduced peak velocity during the second pull (X̄ = 1.52 m/s), insufficient knee re-bending (4.1°), and premature elbow flexion (18.4°). Premature elbow flexion showed a strong negative correlation with peak velocity (r = -0.782; p = 0.003), while excessive anterior horizontal displacement (x₂ = 9.8 cm) increased the drop-under time (r = 0.695; p = 0.012). This extended the drop-under duration to 268 ms and increased the barbell drop velocity to 1.15 m/s. It is concluded that the lack of extension power and angular alterations during the transition represent the main biomechanical factors destabilizing the catch phase and leading to failed lifts.