Integrated virtual reality and musical biofeedback for intensity-guided training on stationary cycling: A comparative feasibility study

Motor rehabilitation requiring sustained physical exercise faces poor adherence in neurological populations due to insufficient supervision and monotony. While virtual reality and musical biofeedback independently improve engagement and motivation, their comparative and combined impact on intensity control strategies during high-intensity interval training (HIIT) remains unexplored. Thirty healthy adults (16 males, 14 females; mean age 27.5 ± 7.2 years) were sequentially assigned to three feedback modalities (n = 10 each) during intensity-guided stationary cycling: visual-only (position-based), musical-only (speed-based), and combined audiovisual (position-based). Participants completed two 9-minute moderate-to-high intensity sessions (Set 1 and Set 2) maintaining pedaling speed within a target speed zone. Performance distinguished control strategy from effectiveness: stability via target zone exits, correction capacity via recovery time and sustained deviations, and overall effectiveness via time in zone. Heart rate (HR) assessed physiological intensity; usability and cognitive workload were evaluated via e-Rubric and NASA-TLX. Distinct regulation strategies emerged. Musical-only showed significantly lower stability (Set 1: 14.52 exits/min vs. 1.48 visual and 1.79 combined; corrected p < 0.0167) but superior correction (0.21s recovery vs. 2.48s and 1.06s; p < 0.0001) with minimal sustained deviations. Combined feedback achieved highest Set 2 effectiveness (98.13% vs. 95.17% time in zone; corrected p < 0.0167) but elevated physical demand (corrected p < 0.0167). HR variability was comparable (p = 0.85), confirming consistent cardiovascular workload despite differing strategies. Satisfaction was high, with slight preference for musical feedback; cognitive workload did not differ. Musical biofeedback promotes reactive control with frequent but rapidly corrected oscillations, maintaining physiological safety and engagement. Visual feedback ensures stable target adherence at the cost of compensatory physical effort. The combined modality did not demonstrate clear synergistic benefits in this implementation, increasing demand without improving effectiveness. These preliminary findings reveal a trade-off between stability and correction agility, supporting tailored modality selection in future clinical applications: musical feedback could be particularly appropriate for unsupervised rehabilitation prioritizing engagement, rapid error correction, and sustainable effort, while visual feedback may better suit supervised protocols requiring stable preventive control and precise adherence quantification.