Effect of Tennis Racket Damper on the Peak Force and Damping Time
Mason Porramatikul MD1, Thiti Meeopartmongkon MD1
Affiliation : 1 Department of Orthopedics, Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Bangkok Thailand
Objective : To study the effect of two damper shapes on tennis racket on the peak force and damping time at the grip area for
a centre or off-axis locations of the ball-impact.
Materials and Methods : The peak force and damping time were tested on tennis rackets grips with 3 different settings: use
of damper: no damper, button damper, or worm damper. Tennis balls were served using a tennis strike-simulating machine
using 30 m/s racket speed. The peak force and damping time were recorded from a force transducer attached to the grip and
were compared when the ball-strokes were at four locations: centre, above centre, below centre, and off-axis.
Results : Both types of dampers did not reduce the impact force at the grip regardless of the location. However, the worm
damper yielded a 15% decrease in damping time of an off-axis impact: 230.2+3.1 ms to 196.1+13.8 ms (p = 0.002). Neither
damper reduced the damping time with the on-axis impacts.
Conclusion : Worm damper reduced the racket’s damping time when the ball impacts in an off-axis position but does not
affect the impact force transmitted to the other locations of the grip.
Keywords : Damping time, Peak force, Impact locations, Damper, Vibration
