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Evaluating the FitMáx questionnaire for fitness-to-dive assessments in a military population.

Source: PubMed, NCBI / U.S. National Library of Medicine

Diving and hyperbaric medicineDijk Pieter D, Clarijs Paul, Wingelaar Thijs TPublished 9/30/2026Last synced 9/17/2026Status: syncedPMID: 42743577DOI: 10.28920/dhm56.3.361-364

This study evaluated the validity of the FitM&#xe1;x questionnaire for estimating VOpeak in 157 Dutch Navy divers and recompression personnel, a population characterised by high physical fitness and occupational demands. While self-reported questionnaires offer a logistically feasible alternative to resource-intensive direct testing, their accuracy in fitness-to-dive assessments remains unclear. Participants completed the FitM&#xe1;x questionnaire prior to cycle ergometry with direct VOpeak measurement. Results showed a moderate correlation (r = 0.631, P < 0.001) between mean estimated VOmax (43.7, SD 5.34 mL&#xb7;kg&#xb7;min) and mean measured VOpeak (45.4, SD 6.52 mL&#xb7;kg&#xb7;min), with the questionnaire systematically underestimating fitness by 1.8 mL&#xb7;kg&#xb7;min, with a 95% confidence interval of agreement limit of &#xb1; 10.9 mL&#xb7;kg&#xb7;min, and a moderate intraclass correlation coefficient of 0.748 (P < 0.001). False-positive and false-negative rates were 8.9% and 10.8%, respectively, raising concerns about reliability for pass/fail decisions. Participants reported difficulties answering questions unrelated to their routine activities, potentially contributing to the observed variability. Given these limitations, including the homogeneous, highly fit sample and the inability to differentiate between subgroups, the Royal Netherlands Navy Diving Medical Center has not adopted the FitM&#xe1;x for fitness-to-dive evaluations. While questionnaires may streamlin

Abstract

This study evaluated the validity of the FitM&#xe1;x questionnaire for estimating VOpeak in 157 Dutch Navy divers and recompression personnel, a population characterised by high physical fitness and occupational demands. While self-reported questionnaires offer a logistically feasible alternative to resource-intensive direct testing, their accuracy in fitness-to-dive assessments remains unclear. Participants completed the FitM&#xe1;x questionnaire prior to cycle ergometry with direct VOpeak measurement. Results showed a moderate correlation (r = 0.631, P < 0.001) between mean estimated VOmax (43.7, SD 5.34 mL&#xb7;kg&#xb7;min) and mean measured VOpeak (45.4, SD 6.52 mL&#xb7;kg&#xb7;min), with the questionnaire systematically underestimating fitness by 1.8 mL&#xb7;kg&#xb7;min, with a 95% confidence interval of agreement limit of &#xb1; 10.9 mL&#xb7;kg&#xb7;min, and a moderate intraclass correlation coefficient of 0.748 (P < 0.001). False-positive and false-negative rates were 8.9% and 10.8%, respectively, raising concerns about reliability for pass/fail decisions. Participants reported difficulties answering questions unrelated to their routine activities, potentially contributing to the observed variability. Given these limitations, including the homogeneous, highly fit sample and the inability to differentiate between subgroups, the Royal Netherlands Navy Diving Medical Center has not adopted the FitM&#xe1;x for fitness-to-dive evaluations. While questionnaires may streamline large-scale assessments, direct exercise testing remains valuable for precise, individualised risk stratification in occupational diving.

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