Vibration-Damping technology in tennis racquets: Effects on vibration transfer to the arm, muscle fatigue and tennis performance

Abstract

High vibration transfer from a tennis racquet to the player may cause discomfort, and is hypothesized to influence performance and the onset of muscle fatigue. This study examined a racquet with a novel vibration damping technology (VDT) designed to mitigate frame vibration. Racquet vibration, post-impact vibration transfer to the player, arm electromyographic activity and tennis performance were compared to a non-VDT racquet. Nineteen young adult, competitive tennis players hit forehands and serves until near exhaustion on two days; using one of the two racquets each day. Tri-axial accelerometers mounted to racquet shaft, hand and forearm recorded vibration behaviour. Surface electromyography recorded activity of five arm muscles. In comparison to the non-VDT racquet, the VDT design showed: 1) A significantly lower mean normalised acceleration signal energy at the racquet during unfatigued play (−40%) and at near exhaustion (−34%), which corresponded to a 20–25% lower signal energy at the hand. 2) Reduced signs of arm muscle fatigue at near exhaustion, which was most pronounced in biceps and wrist extensors. 3) Players hit 11% more forehands and placed 40% more hits in the target area at near exhaustion. Conclusion: VDT effectively reduces racquet vibration. Initial evidence indicates that it may delay muscle fatigue, which was associated with increased ball placement accuracy. Keywords: Acceleration, Biomechanics, Electromyography, Human, Kinematics