Lower Limb Muscle Strength and Power Predict Exercise-Induced Prefrontal Hemodynamic Response: An Interpretable Machine Learning Study Using fNIRS Data

Inclusion Criteria

Inclusion Criteria: 1. Healthy adults aged between 18.00 and 60.00 years. 2. Must be able to perform standardized lower-limb physical assessments, including isokinetic strength testing and explosive power tests (e.g., CMJ, SJ, and 30m sprints). 3. Capability to complete a 6-minute aerobic cycling task at a moderate intensity (60% VO\_2max). 4. Physically cleared for exercise as determined by a Physical Activity Readiness Questionnaire (PAR-Q). 5. Willingness to undergo functional near-infrared spectroscopy (fNIRS) monitoring with a Scalp Coupling Index (SCI) ≥ 0.7. Exclusion Criteria: 1. History of musculoskeletal injuries to the lower limbs within the past 6 months that would impede maximum voluntary contraction (MVC) or high-intensity efforts. 2. Known cardiovascular, respiratory, or neurological conditions that contraindicate maximal exercise testing (VO\_2max ramp protocol). 3. Body Mass Index (BMI) or health status that prevents the safe completion of high-impact explosive power tests like the 30cm drop jump (RSI assessment). 4. Presence of excessive motion artifacts or poor fNIRS signal quality, specifically a Signal-to-Noise Ratio (SNR) \< 5 dB or motion artifact frame ratio ≥$ 10%.