EXPLORING HAPTIC FEEDBACK ON KINESTHETIC AWARENESS: A CASE STUDY Jo Shattuck, Jack Ransone, University of Nebraska and the Nebraska Athletic Performance Laboratory, NE, USA Email:
[email protected], website: http://www.huskers.com INTRODUCTION Proprioception (kinesthetic awareness), of the precise joint angles of the effector is especially critical in the cognitive and associative stages of motor learning [1]. The ability to replicate an effector angle in any skill involving a ball and target is crucial for successful ball control. In order to replicate and correct a movement, the subject must have accurate and consistent knowledge of the body’s position. Kinesthetic awareness training (KAT) provides the addition of haptic feedback in real time, to introduce secondary discriminatory system information into kinesthetic processing to improve kinesthetic awareness. We propose that haptic feedback through KAT will improve the ability to replicate a joint angle in multi-joint movements [2]. We tested this hypothesis on multiple movements. This dataset refers only to forearm angle replication during shot preparation movement in basketball.
To maintain a ‘real-world’ basketball environment, the subject could choose to whether or not to shoot the ball. Our outcome measures were: 1) Time-to-target: samples needed to replicate shot preparation forearm angle after catching the ball. A beginning reference point began when the angle was within 40 degrees of the target. Angle was considered IN when within 4 degrees of the target. 2) HIT/MISS rate: For each trial, a HIT was recorded if the subject held the angle for 2 consecutive samples. A MISS was recorded if the target angle was not reached for 2 consecutive samples. MISSES/HITS is the MISS rate.
METHODS We assessed peripheral limb control, specifically the vertical angle of the right forearm during a basketball shot measured with and without real-time haptic feedback. Four participants, (3 males, 1 female, each was either 20 or 21 years old), wore a miniature motion-capture and feedback device with internal sensors that recorded continual position data in 8 axes at approximately 16Hz. The target angle was determined by the subject, who held the basketball in their desired shot preparation position for 2 full seconds. The precise angle was then captured into the KAT tool through the smartphone app. A researcher then bounce-passed the basketball to the subject from 12 feet away; the subject was asked catch the ball, then return to the shot preparation pose as quickly and accurately as possible, as if preparing to shoot. The device was programmed to automatically provide haptic vibrations while the forearm angle was replicated.
Figure 2: KAT placement. Figure 1: Forearm at target angle. The subject wore the KAT on the forearm continually as we collected three sets of five trials: a pre-training baseline set, a KAT condition set with haptic feedback, and a post-test set withoutfeedback, for a total of 15 trials per person. It is important to note that the goal was not to achieve any particular forearm angle across subjects, nor to test the effectiveness of any particular angle on shooting success, but instead, to test each subject’s ability to replicate their chosen effector angle, that they determined for themselves before the task.
41st Annual Meeting of the American Society of Biomechanics, Boulder, CO, USA, August 8th – 11th, 2017
RESULTS AND DISCUSSION Single-tail paired T-tests of pre and post KAT in within-subject comparisons showed significant differences in time-to-target, in 2 of the 4 subjects. (p = 0.02 and p = 0.03 for subjects 3 and 4). One notable effect was the HIT/MISS ratio across all subjects in both conditions. The MISS rate in the KAT conditions was lower than in non-KAT sets (5% misses in KAT sets and % 26 misses in nonKAT sets.
Figure 3: Outcome measure in a single trial. This data is part of an ongoing study testing motor performance simple and complex movements. In this subset of data two of the within-person comparisons showed significant improvement in time needed to replicate the target angle with KAT. Also, the total MISS rate was 5 times lower in the non-KAT sets when compared to the KAT sets. Our sample size is not large enough to show meaningful differences in angle replication, however, this case study reports on the findings regarding motor behavior when haptic feedback is implemented in a motor task. Visible overshoots and undershoots of the target angle happened more frequently in the KAT conditions, presumably the reflecting the kinesthetic awareness as the subject ‘explored’ the effector position and felt the haptic feedback. Logically, subjects spent more time in the target angle in the KAT conditions, although this was not part of the instructions to the subject. In future studies, improvements to the methods will include a larger sample size, more trials per set, and two groups design, one with feedback, and one without, instead of alternating conditions, to better control the practice effect.
Further experiments are warranted to determine if KAT training can improve kinesthetic awareness, and more importantly, if the improvement translates to increased performance of a motor skill. CONCLUSIONS This effort was the first use of a novel feedback/ monitoring device. The study was not intended to determine the optimal forearm angle of a basketball shot, but instead to test angle replication skill, reflecting our measure of kinesthetic awareness. The results show that a miniature motion capture device could be used to test biomechanical techniques in motor skill in real-life situations, without the restraints of in-laboratory multi-camera marker systems. It is logical that a device that offers vibratory corrective feedback, at the exact instant the correct angle is replicated, would lead to that angle indeed, being replicated, during a movement. The larger purpose is to investigate haptic feedback as an intervention in human movement. Real-world applications include basic motor skill acquisition [2], clinical rehabilitation, post-trauma physical therapy, movement disorders, neurosensory motor dysfunction, and/or other rehabilitative populations with kinesthetic awareness deficits. REFERENCES 1. Sigrist
R, Rauter G, Riener R, Wolf P Psychon Bull Rev 20:21–53, 2013 2. Marchal-Crespo L, Van Raai M, Rauter G, Wolf P, Riener, Exp Br Res 231, 277:291-3, 2013 ACKNOWLEDGMENTS Thank you to the University of Nebraska, and Nebraska Athletic Performance Laboratory. Disclosure: The kinesthetic awareness training device/technique is provisionally patented by the principle investigator and PANTHER: Principles of Athletics and Neuroscience Toward Human ExpeRtise.
41st Annual Meeting of the American Society of Biomechanics, Boulder, CO, USA, August 8th – 11th, 2017
