Design and Setting

This study was approved by the institutional review board (IRB-2018-2-10) of Korea University of Technology and Education (KOREATECH), South Korea. To examine the effect of the VR content in the ski exergames, we performed 2 experiments in which participants exercised on a motion platform with and without VR content. We measured the range of motion (ROM) of the ankle and rated perceived exertion (RPE) of the ankle to assess exercise capacity. Moreover, electroencephalography (EEG) was performed to assess concentration of the user. An experimental environment is shown in Figure 1.

Experimental environment. EEG: electroencephalogram; IMU: inertial measurement unit; ROM: range of motion; VR: virtual reality.

The ski motion platform (Basic Ski Simulator, Pro Ski Simulator) [11] enables the users to experience real skiing by moving the foothold side to side. Using the VR content (Ski Fit 360, Studio 360 Connect) [12], users can experience alpine ski racing (a virtual downhill scenario, where a user passes through 55 gates in a minute). Here, the ROM of the ankle in the sagittal plane is measured using an inertial measurement unit (IMU). Brainno [18] is a device that measures the EEG noninvasively using 2-channel dry type electrodes. It records the measured EEG according to frequency bandwidth of delta (0~3 Hz), theta (4~7 Hz), alpha (8~12 Hz), sensorimotor rhythm (SMR, 13~15 Hz), M-beta (16~20 Hz), H-beta (21~30 Hz), and gamma (over 31 Hz) waves.