Correlation Between Maximal Eccentric and Isometric Multi-Joint Lower-Extremity Strength and Vertical Jumping...

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Maximal eccentric (MES) and isometric (MIS) muscle strength are theorized to improve vertical jump performance by optimizing the stretch-shortening cycle (SSC).
• Previous research has yielded unclear results due to varied assessment methods and limited metrics for evaluating the contributions of MES and MIS to countermovement jumps (CMJ) and depth jumps (DJ).

Purpose of the Study:

• To investigate the correlations between multi-joint lower extremity MES and MIS with various ground reaction force (GRF) measures during CMJ and DJ.
• To clarify the relationship between maximal strength capabilities and the biomechanical அம்ச of vertical jumping performance.

Main Methods:

• Twenty-five healthy adults performed maximal effort CMJs and DJs.
• MES and MIS were assessed using a seated multi-joint isokinetic dynamometer.
• Thirteen vertical GRF measures were collected and analyzed using Pearson r correlations (α = 0.05).

Main Results:

• Moderate-to-strong positive correlations were found between MES/MIS and jump height, reactive strength index (RSI), and modified RSI in both CMJ and DJ.
• Positive correlations were observed between MES/MIS and concentric (CON) work and peak power.
• Negative correlations were identified between MES/MIS and eccentric (ECC) work and peak power.

Conclusions:

• Enhanced MES and MIS are associated with improved vertical jump performance, particularly in RSI and jump height.
• Stronger musculature appears to reduce eccentric energy absorption, enhancing elastic energy utilization for propulsion.
• These findings highlight the importance of maximal strength in optimizing force application, energy transfer, and control during the SSC for superior jumping ability.