Evaluation of Upper Limb Joint Contribution to Racket Head Speed in Elite Tennis Players Using IMU Sensors: Comparison between the Cross-Court and Inside-Out Attacking Forehand Drive

Abstract

This study aimed to quantify and compare the upper limb angular kinematics and its contributions to the racket head speed between the cross-court (CC) and inside-out (IO) attacking tennis forehand of elite tennis players in a competitive environment. A new approach was used to study the forehand drive with mini-inertial sensors of motion capture to record the kinematic data. Six strokes in each direction per participant (72 shots in total) were chosen for analysis. Upper limb kinematics were calculated in the Visual 3D platform (Visual 3D Professional V5.01.21, C-motion, Germantown, MD, USA). The method used to calculate the upper limb’s contributions was performed with MATLAB software and used the segment’s (upper arm, forearm and hand) angular velocities and their respective displacement vectors obtained through the inertial sensors. Upper limb kinematics demonstrated a higher shoulder rotation in the IO direction with significant differences at the end of the backswing, which could be a key factor in distinguishing the two directions of the shot. Results also demonstrated that the horizontal flexion of the upper arm (around the shoulder joint) was primarily responsible for the racket velocity in the anteroposterior direction (48.1% CC and 45.2% IO), followed by the extension of the forearm (around the elbow joint) (17.3% CC and 20.9% IO) and the internal rotation of the upper arm (around the shoulder joint) (15.6% CC and 14.2% IO). No significant differences were shown in the contributions of upper limbs to the racket head velocity between the two directions of the shot. Tennis coaches and players should develop a specific training programme to perform higher angular velocities in these specific joint rotations.

Biomechanical analyses of different serve and groundstroke techniques in tennis: A systematic scoping review

“…A total of 229 subjects were examined in the included studies. Sixteen studies [ 4 – 7 , 9 , 12 – 14 , 17 – 24 ] investigated only male players, while seven papers [ 8 , 11 , 21 , 25 – 28 ] studied mixed players group. Five studies [ 11 , 17 – 20 ] did not report the players’ age, and the remaining studies investigated adult players.…”

“…Five studies [ 11 , 17 – 20 ] did not report the players’ age, and the remaining studies investigated adult players. Ten studies [ 4 , 8 , 11 , 14 , 17 – 20 , 25 , 29 ] analysed the tennis serve, eleven publications [ 5 – 7 , 9 , 12 , 13 , 21 , 23 , 24 , 27 , 28 ] investigated the forehand groundstroke, and two investigations [ 22 , 26 ] examined the forehand and backhand groundstroke.…”

A low carrying angle is measured in elite tennis players just before ball impact during the forehand, suggesting a dynamic varus instant accommodation moving towards full extension

“…As a further limitation, the measurements were performed on bi‐dimensional images, which can minimally bias measurements due to perspective distortion; the authors tried to avoid this by carrying out a meticulous selection of the 306 available videos and accepting only the 16 images deemed unbiased. The application of wearable sensors, which is now gaining popularity in orthopaedics and sports medicine, was not considered in the time frame 2014–2016 since potentially altering the athletic gesture; nevertheless, comparable accuracy of bi‐ and tridimensional measurement methods for the carrying angles was reported, supporting the use of a bidimensional method in this selected population [18, 39, 40]. For obvious reasons, radiological measurements of the carrying angle were also not possible.…”

Athletic Mobile Manipulator System for Robotic Wheelchair Tennis

“…To hit a successful return, humans generate high racket head speeds by merging contributions from multiple body joints [44]. Inspired by this "summation of speed principle" [45], we created a "Fully-Extended" Ground stroke (FEG) that maximizes the racket speed when it makes contact with Fig.…”