Investigating the validity, reliability and usefulness of 30-15 intermittent roller test (IRT) for inline roller sports

Abstract

Background and Study Objective: The 30–15 Intermittent Fitness Test (30–15IFT) is widely used to assess intermittent aerobic fitness in team sports. However, its applicability into inline roller sports (roll ball and roller hockey) has not been sufficiently investigated. Therefore, this study aimed to examine the reliability, usefulness, and validity of a modified 30–15 Inline Roller Test (30–15IRT) for assessing aerobic fitness in inline roller sports. Materials and methods: Forty-three male Tier-3 inline roller athletes (aged ≥18 years; ≥5 years of playing experience) participated in this study. Participants completed the 30–15IRT under sport-specific conditions in an inline roller arena while wearing their regular skating equipment. Physiological and performance variables, including blood lactate concentration, submaximal heart rate stages (HRStage 4 and HRStage 8), peak heart rate (HRpeak), total distance covered, maximal skating speed (VSIRT), and estimated VO₂peak, were recorded. Test– retest reliability was assessed using intraclass correlation coefficients (ICC), coefficient of variation (CV), and typical error (TE), while usefulness was determined using the smallest worthwhile change (SWC). Concurrent validity was evaluated by correlating the 30–15IRT with the 30–15IFT. Results: The 30–15IRT demonstrated moderate to good reliability (ICC = 0.68–0.82). Low variability was evident in heart rate and performance measures (CV = 1.20–2.80%), whereas blood lactate responses showed comparatively higher variability (CV = 7.03-16.46%). The test showed acceptable usefulness for detecting moderate changes (SWC0.6). Moderate to strong correlations were observed between the 30–15IRT1 and 30–15IFT for physiological variables (r = 0.72– 0.76) Conclusion: The 30–15IRT is a reliable and sport-specific field test for assessing intermittent aerobic fitness in inline roller athletes. It demonstrates acceptable validity for physiological responses and may assist coaches in fitness monitoring and individualised training prescription.