Active tuning of stroke-induced vibrations by tennis players

Abstract

This paper investigates how tennis players control stroke-induced vibration. Its aim is to characterise how a tennis player deals with entering vibration waves or how he/she has the ability to finely adjust them. A specific experimental procedure was designed, based on simultaneously collecting sets of kinematic, vibration and electromyographic data during forehand strokes using various commercial rackets and stroke intensities. Using 14 expert players, a wide range of excitations at spectral and temporal levels were investigated. Energetic and spectral descriptors of stroke-induced vibration occurring at the racket handle and at the player's wrist and elbow were computed. Results indicated that vibrational characteristics are strongly governed by grip force and to a lower extent by the racket properties. Grip force management drives the amount of energy, as well as its distribution, into the forearm. Furthermore, hand-grip can be assimilated to an adaptive filter which can significantly modify the spectral parameters propagating into the player's upper limb. A significant outcome is that these spectral characteristics are as much dependent on the player as on the racket. This contribution opens up new perspectives in equipment manufacture by underlining the need to account for player/racket interaction in the design process.

3D propagation of the shock-induced vibrations through the whole lower-limb during running

“…Studies showed that the acceleration is attenuated from the tibia to the upper-parts of the body and hypothesized on the attenuation processes developed by the musculoskeletal system. This result is also corroborated from a spectral point of view, as several studies stated that the human body acts as a low-pass filter for the input vibration regarding the lower-limb (Edwards et al, 2012, Shorten andWillow, 1992) as well as the upper-limb (Chadefaux et al, 2017).…”

“…Running is an integral component of many sports, where the impact of the feet on the ground generates vibrations propagating through the entire body. Shock-induced vibrations have been recognized as being influential to the feeling of comfort in the feet (Barrass et al, 2006;Stroede et al, 1999), the biomechanical control of the performance (Chadefaux et al, 2017), and to the risk of fatigue and injury (Lafortune et al, 1996). Repetitive impacts during running have been investigated relative to the risk of injuries such as tibial stress fracture, spinal injuries, or joint and cartilage damages (Lafortune et al, 1996;Milner et al, 2006;Zadpoor and Nikooyan, 2011).…”

Cellists’ sound quality is shaped by their primary postural behavior

“…Sports biomechanics is one example of a domain where body posture, dynamic somatic practice, and motor control need to remain inherently and strongly connected to ensure the efficiency of a given action 66 , 76 , 77 , 108 . For example, research on human-material interfaces demonstrated that tennis players or runners need to finely tune the shock vibrations induced by the racket or the ground surface 109 – 111 . In that context, functional data analyses may provide an opportunity to infer continuous patterns of adaptation between the effector limb (hand or foot) and the entire body of these athletes.…”

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

“…It is known that the mechanical vibrations of the racquet transferred to the human body are largely absorbed by soft tissue. Peak-to-peak acceleration and signal energy measured at the racquet is attenuated four-to six-fold at the wrist 4 , 5 , 16 and becomes further reduced when transferred from the wrist to the elbow. 5 , 17 It is less well understood how a reduced level of vibration transfer to the arm affects the underlying muscle activity needed to stabilize the wrist and elbow during play.…”

“… 2 Players can modulate vibration transfer to their hand/arm by adjusting the location of ball impact 3 , 4 or their grip force. 1 , 5 , 6 …”