This preliminary study aimed to assess changes in motor responses following the Concurrent Virtual Reality Headshake and Weight Shift Training (Concurrent VR HS-WST).
In this crossover design, thirteen healthy older adults (69.53+4.54years; 1.67+0.09m) were placed in two groups. Group 1 (n = 9) received the intervention (T) for 7 days, followed by a 7-day washout period (WO), and a 7-day no-training (NT) period. Group 2 (n = 4) followed a similar protocol in reverse sequence. Participants donned an Oculus Quest 2 headset in a standing position on the floor or Airex foam. In performing the weight shift activities, participants followed a virtual environment (UpRight VR, LLC, Temple University) which instructed them to lean as quickly as possible (without taking a step) to accurately reach visual targets (every four seconds) that surrounded them in eight possible directions. While participants performed the weight shift, in some of the exercises, they concurrently rotated the head in a horizontal rhythmic pattern (+30°) synchronously to a metronome (80-120 beats/min). Each day’s session comprised 18 exercises, each lasting for one minute. Pre- and post-dynamic balance on a ramp down perturbation force plate device (simulating being pushed forward) was assessed during both T and NT periods with electromyography on participants’ postural muscles.
Training resulted in statistically significant increase in five muscles, namely, neck flexors and lower limb muscle activations. These were evident in the sternocleidomastoid (SCM) right (change = 2087.56mv, p = 0.032) and left (change = 650.28mv, p = 0.010); rectus femoris (RF) right (change = 37.58mv, p = 0.003) and left (change = 434.05mv, p = 0.017); and left tibialis anterior (TA, change = 256.10mv, p = 0.047). In addition, three muscles exhibited statistically significant changes in activations during the NT period. There was decreased activation in the right cervical erector (change = -372.34mv, p = 0.035) and right TA (change = -341.61mv, p = 0.002), while the left cervical erector showed an increase in activation (change = 517.23mv, p = 0.039). The three muscles that showed significant changes during the NT session were mainly due to the learning effect and possible motor consolidation of Group 1 which also had over twice the number of participants.
The short-duration treatment sessions of the Concurrent VR HS-WST modify both upper and lower body postural muscles to refine activation levels and stabilize the body when subjected to forward sways. Refining the activation patterns of these muscles following the training would improve postural balance.
Findings suggest clinicians should simultaneously incorporate vestibular activation into balance training to promote optimal muscle activation and enhance therapeutic outcomes.
headshake
weight shift training
