Reproducibility and validity of the stair-climb test for fire fighters

Abstract

A new job-specific test for fire fighters, the stair-climb test (FFstair-climb) was evaluated for reproducibility and validity for use in future workers' health surveillance. The FFstair-climb was performed at three times by 20 male fire fighters (one and three weeks in between test and retest) to examine the reliability and agreement. An intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated. In addition, 45 fire fighters (2 women, 43 men) performed the test once, while heart rate and testing time were monitored, to study the content validity. Construct validity was tested by correlating both self-rated and supervisor-rated work ability scores with testing time. The reliability, reflected by the ICC, was high for the one-week and the three-week test-retest period, 0.82 and 0.91, respectively. The mean testing time for the FFstair-climb was about 65 s; the agreement showed SEMs of 5.4 s at the one-week test-retest period and 3.8 s at the three-week test-retest period. Content validity was good in 78% of the fire fighters, while the construct validity between testing times and work ability ratings was not sufficient (r < 0.30). The FFstair-climb can be used in the Workers' Health Surveillance of fire fighters as a reproducible instrument, with good content validity. Testing criterion validity in future research would be an appropriate next step.