this study will compare two warm-up methods before cardiopulmonary exercise testing (CPET) in recreationally active young adults. Participants will complete treadmill walking or TRX suspension warm-up, followed by a treadmill exercise test to exhaustion. The investigators to determine whether suspension warm-up produces similar peak oxygen uptake (VO2max) and cardiopulmonary responses as treadmill walking.

CPET is the gold standard for assessing aerobic fitness. Warm-up procedures may influence outcomes. Traditional CPET warm-up uses walking or cycling, but suspension training provides a dynamic, full-body option. This randomized, counterbalanced crossover study will compare VO₂max and secondary outcomes (time to exhaustion, HRmax, RER, VE, BP, VT) after treadmill vs suspension training warm-up. The primary analysis is a non-inferiority test with a 5% margin for VO₂max.

Inclusion Criteria:

Aged 19 to 25 years

Engages in ≥5 hours per week of moderate-to-vigorous physical activity (classified as "high activity" based on the International Physical Activity Questionnaire [ICIQ])

Able to pass the Physical Activity Readiness Questionnaire (PAR-Q+) screening

Exclusion Criteria:

Participates in <5 hours per week of moderate-to-vigorous physical activity

Contraindications to maximal cardiopulmonary exercise testing or suspension training

Presence of any medical condition that may interfere with safe test participation or data interpretation

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The individual participant data (IPD) will not be made publicly available because this is a small, single-site academic study conducted for exploratory purposes, and data sharing is not required by the sponsor or funding agency. Summary results will be posted on ClinicalTrials.gov and may be included in peer-reviewed publications.

open label