Poor Joint Work in the Lower Limbs during a Tennis Forehand Groundstroke after a Cross-Over Step Inhibits an Increase...

Area of Science:

• Biomechanics
• Sports Science
• Kinetics

Background:

• Forward run-up and stepping are crucial for accelerating hitting tools in sports.
• Understanding the biomechanical impact of specific movements like the cross-over step is vital for performance optimization.

Purpose of the Study:

• To investigate the effect of a forward cross-over step on hitting tool speed.
• To analyze joint work and mechanical energy changes in tennis players performing forehand groundstrokes.

Main Methods:

• Inverse dynamics analysis was used to examine whole-body and hitting tool mechanics.
• Thirteen advanced tennis players performed forehand groundstrokes with and without a cross-over step at maximum effort.

Main Results:

• The cross-over step increased body-weight-normalized mechanical energy at the motion's start.
• Total negative joint work, mainly from lower limbs, increased, acting as energy absorption.
• Despite comparable whole-body energy at impact, the playing upper limb's mechanical work and energy increased, resulting in a 4.3% higher racket speed.

Conclusions:

• The forward cross-over step enhances upper limb contribution to racket speed, but overall energy transfer efficiency is similar.
• Players and coaches should maintain a balanced perspective on the forward step's influence on racket speed.