Participants follow a training program based on race pace zones, including both low-intensity sessions and high-intensity intervals.

Participants follow a training program based on heart rate zones, including both low-intensity sessions and high-intensity intervals.

Participants complete one week of endurance training based on race pace zones individually determined from a 5-km time trial performance. The program includes both low-intensity continuous runs and high-intensity interval training sessions.

VO₂max (mL·kg-¹·min-¹) measured during an incremental treadmill test to volitional exhaustion. Respiratory gases are collected breath-by-breath using a calibrated metabolic cart. The highest 30-second average of VO₂ is taken as VO₂max.

Total time (in minutes and % of intended time in zone) spent within the prescribed low-intensity training zone during each session, as determined by either heart rate (below first ventilatory threshold) or race pace (based on individual 5-km performance). Training zones are predefined per method and monitored via GPS watches and heart rate monitors.

Total time (in minutes and % of intended time in zone) spent within the prescribed high-intensity training zone during interval sessions, based on either heart rate (above second ventilatory threshold) or race pace (percentage of 5-km race pace). Time in zone is extracted from GPS and HR data post-session

These variables will be assessed to monitor changes in general health status and body composition throughout the intervention.

Weight and height will be measured using a calibrated bio-electrical impedance analyzer (Tanita MC-780), with an accuracy of ±0.1 kg. Participants will be assessed barefoot, wearing light clothing, after an overnight fast and after voiding. Weight will be recorded in kilograms (kg) and height in meters (m), and BMI will be subsequently calculated as weight divided by height squared (kg/m²).

No additional outcome measures will be collected in this assessment session.