Author(s): FERGUSON, A., BISSAS, A., DE STE CROIX, M., Institution: UNIVERSITY OF GLOUCESTERSHIRE, Country: UNITED KINGDOM, Abstract-ID: 2282

INTRODUCTION:
Fitness assessments for UK firefighters verify their capacity to meet operational physical demands. Submaximal gym-based cardiorespiratory tests are commonly used due to practicality. This study evaluated performance across approved assessments to determine whether they appropriately reflect minimum occupational standards in a diverse workforce.
METHODS:
A total of 360 operational firefighters (277 men, 83 women) from a UK Fire and Rescue Service completed annual submaximal cardiorespiratory testing using the Chester Treadmill Test. Resting blood pressure (BP) and heart rate (HR) were recorded before exercise, with HR and rate of perceived exertion (RPE) monitored throughout. Group differences by stature, BMI, sex, and age were analysed using independent-samples t-tests. Predicted maximum HR (%HRmax) was calculated using 208 − (0.7 × age).
RESULTS:
Participant characteristics included age (men 40.6 ± 10.3 y; women 38.0 ± 9.4 y), stature (men 1.78 ± 0.06 m; women 1.66 ± 0.05 m), mass (men 89.2 ± 13.9 kg; women 69.7 ± 9.4 kg), BP (men 146/87.7 ± 15.3/11.0 mmHg; women 128.3/80.8 ± 12.1/11.0 mmHg), and resting HR (men 74.0 ± 8.7 bpm; women 77.4 ± 8.3 bpm). Mean HR at 12 min was 172.7 ± 16.0 bpm. Pass rates did not differ between sexes. Women showed higher mean %HRmax at several stages despite no significant differences in absolute HR. Significant sex differences in %HRmax were observed at 4 min (p < 0.01), 6 min (p < 0.001), and 8 min (p < 0.01); no difference was observed at 12 min. Both groups finished at an average of 96% predicted HRmax. When stratified by stature (>1.76 m vs. ≤1.76 m), taller participants had higher pass rates (91% vs. 85%) and longer test duration achieved (p < 0.05), with no difference in %HRmax. Stratified by both sex and stature, shorter women demonstrated higher %HRmax at stage four (p < 0.05) and stage five (p < 0.01), higher overall %HRmax (p < 0.05), and lower pass rates (p < 0.019). In men, stature differences were observed only for test duration (p < 0.05). No differences in overall %HRmax or pass rates were observed when stratified by age (>38 vs. ≤38 y), BMI (<25 vs. ≥25), or stature alone beyond the sex-specific effects described. The older subgroup demonstrated higher %HRmax at stage one (p < 0.01), stage two (p < 0.01), and stage three (p < 0.01) only.
CONCLUSION:
Most firefighters met minimum occupational standards despite differences in sex, age, and anthropometry. However, variation in %HRmax responses suggests the fixed-speed submaximal Chester Treadmill Test may impose unequal physiological demands. Although absolute HR was similar between sexes, women demonstrated greater relative cardiovascular strain at equivalent workloads. The mean attainment of 96% predicted HRmax suggests the test may not remain truly submaximal in practice. While current criteria confirm baseline fitness, reliance on predicted capacity and non-individualised workloads may reduce sensitivity in distinguishing fitness across a diverse firefighter population.