JMIR Publications

ABSTRACT

Background:

Motor training is essential for restoring knee function in several medical conditions. Open and closed kinetic chain (OKC/CKC) exercises are widely used to enhance proprioception. Exergames, supported by wearable sensors, offer a solution by providing real-time feedback. Auditory feedback (AF) embedded in the serious game training has shown benefits in upper limb rehabilitation compared to visual feedback (VF) alone. However, the potential of auditory feedback in exergames that provide knee training is not known.

Objective:

This study presents an exergame platform aimed at enhancing knee joint proprioception through stretching and squatting exercises. The platform allows to provide feedback in two modes, namely VF only and a combination of AF and VF. The auditory feedback is a sonification of the joint position. The VF maps the motion of the lower limb into the game space where this information is used to control a game object. A randomized controlled pilot study with 14 participants compared augmented AF to VF only. The hypothesis was that AF would improve knee joint position accuracy, enhancing neuromuscular coordination and lower limb stability.

Methods:

14 healthy volunteers tested the exergames for knee joint motor learning using AF. All participants were required to do a pre-test consisting of half and full squats. In addition, participants were asked to reproduce a 45-degree knee bent and to stretch their knee fully as part of the pretest. After that participants played 4 rounds of each of the two exergames. Then the tasks of the pre-test were repeated. A one-sided Mann-Whitney U Test was conducted for answering whether AF has a positive effect on the ability of participants to accurately control the knee joint angle. In addition, we calculated the muscle synergies participants used to complete the exercises. Subjective experience during game play was assessed using the Intrinsic Motivation Inventory (IMI) and the User Experience Questionnaire (UEQ).

Results:

A total of 14 participants were recruited, including 7 in the experimental group (EG) with combined VF and AF feedback, and 7 in the control group (CG) only with VF. The result of the Mann-Whitney U test demonstrated that AF improved knee joint accuracy compared to VF in both the CKC (statistics=41.0, p = 0.0379) and OKC (statistics=42.0, p = 0.0262) tasks. Additionally, muscle synergy analysis revealed high consistency in different muscle synergy patterns between groups across both game types.

Conclusions:

AF significantly enhanced knee joint motor learning performance (reflected in the knee joint angle positioning ability in this study) in both CKC and OKC exergame training. Consistent muscle synergy patterns across participants show that the developed exergames are suitable for knee training. Studies in patient populations are needed to establish whether the games could be used in lower limb rehabilitation.