Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Jump performance is crucial in many sports.
• The influence of initial joint angles on jump mechanics is not fully understood.
• Understanding intersegmental coordination is key to optimizing jump technique.

Purpose of the Study:

• To investigate the impact of varying knee starting angles on jump performance.
• To analyze kinetic parameters and intersegmental coordination during squat jump (SJ) and countermovement jump (CMJ).
• To determine optimal knee angles for maximizing jump height and power.

Main Methods:

• Twenty male athletes from volleyball and basketball participated.
• Jumps were performed with controlled knee flexion angles: CMJ(<90°), CMJ(>90°), CMJ(PREF), SJ(70°), SJ(90°), SJ(110°), and SJ(PREF).
• Jump performance, kinetic parameters, and continuous relative phase for intersegmental coordination were analyzed.

Main Results:

• Best jump performance was achieved with higher squat depths (CMJ(<90°) and SJ(70°)) and preferred positions.
• Peak power output was highest in SJ(110°) and CMJ(>90°).
• Greater squat depth led to more in-phase thigh-trunk coupling; CMJ(>90°) and SJ(PREF) showed more in-phase leg-thigh coupling.

Conclusions:

• Starting jumps from a more flexed knee position is a beneficial strategy for enhancing jump performance.
• Initial knee angles significantly affect both jump performance and the coordination patterns between body segments.
• Athletes can optimize their jumping technique by adjusting their initial knee flexion angle based on jump type.