An Instrumented Grip Handle for Golf Clubs to Measure Forces and Moments Exerted by Each Hand During Swing Motion

Optimisation of the upper body motion for production of the bat-head speed in baseball batting

“…The knob-side shoulder adduction/abduction and elbow flexion/extension torques displayed substantial differences between the second and third optimisations. Several studies have concluded that the hand force and joint torque of the knob-side were larger than those of the barrelside in baseball batting (K. Ae et al, 2014;Koike et al, 2004;Koike & Mimura, 2016). The variation of the joint angles in the optimised performance was allowed within ±2 SD of the standard motion data, and the subsequent RMSE of the joint torques was relatively small (Table 2), when compared to the exerted peak joint torques of the upper limbs observed previously (K. Ae et al, 2014).…”

“…Fifty-three retroreflective markers, including six placed on the bat, were captured using a motion capture system with 12 cameras (VICON-MX, Vicon Motion Systems, Ltd., Oxford, UK) operating at 250 Hz. Force and moment of the individual hands were measured with an instrumented grip-handle equipped with 28 strain gauges (1000 Hz) that had a similar structure to the instrumented bat proposed by Koike et al (2004). The marker positions were placed according to the method of K. Ae et al (2017).…”

“…Joint angular accelerations were calculated as the second-order differential of the joint angles of the standard motion, which is the relative angle between proximal and distal segments using Euler (Cardan) angle, for use as input to the simulation model. The period of the bat swing was defined as the time from the instant at which the sum of speeds of the bathead and handle exceeded 3 m/s until one frame before ball impact to avoid distortion of the data (K. Ae et al, 2013Ae et al, , 2014Koike et al, 2004).…”

“…In baseball batting, it is not possible to calculate the joint force and torque of the upper limbs due to 'closed loop problem' (Vaughan et al, 1982a(Vaughan et al, , 1982b. The force and moment of the individual hands were distributed by the optimisation procedure, dependent on the measured kinetic variables of the individual hands (K. Ae et al, 2013Ae et al, , 2014Koike et al, 2004). In order to evaluate the accuracy of the simulation model, a root mean squared error (RMSE) between the measured and simulation model data was calculated for the time histories of bat-head speed, bat orientation angle and joint angles (17 DOFs).…”

Differences in shaft strain patterns during golf drives due to stiffness and swing effects

“…Both Suzuki et al [21] and Nesbit [22] claim that highly skilled golfers can use joint torque profiles that influence shaft deflection in a way that allows an efficient utilisation of energy stored in the shaft. Koike et al [23] measured a golfer's torque and force inputs to the shaft directly using an instrumented grip. They only presented preliminary results for one scratch golfer, but the trend for the wrist torque to drop towards a zero or negative torque within the last 0.05 s of the downswing can also be observed in their results.…”