Cranial anthropometry and physical conditioning in relation to handstand endurance and fixed-roller task performance in male flight cadets

To explore associations of cranial anthropometric and physical-conditioning measures with handstand endurance and 30-second fixed-roller task performance in male flight cadets. In this cross-sectional study, 77 male Han Chinese flight cadets aged 18–19 years underwent assessment of six cranial anthropometric measures. Two laboratory outcome domains were analyzed: handstand endurance time, representing static inversion motor performance, and 30-second fixed-roller rotation performance, representing dynamic fixed-roller task performance. Calculated − Gz was derived mathematically from fixed-roller angular velocity and participant-specific radius and was retained solely as a mechanical descriptor of the fixed-roller task rather than as a separate outcome or measure of physiological tolerance. Handstand endurance and fixed-roller rotation count were treated strictly as laboratory task-performance outcomes. Neither was considered a validated surrogate for physiological or operational − Gz tolerance. Crude evidence for cranial associations was limited to an inverse correlation between head breadth and handstand endurance (r = − 0.30, 95% CI − 0.49 to − 0.08; p = 0.008; q = 0.049). However, no cranial variable was independently associated with handstand endurance in the systematic adjusted model, and the cranial domain was not supported by the joint robust Wald test (p = 0.307). Cranial measures were also not associated with 30-second fixed-roller rotation count in the corresponding joint test (p = 0.917). Pull-up count was positively associated with 30-second fixed-roller rotation count: each 1-SD increase in pull-up performance was associated with 0.924 additional rotations over 30 s (95% CI 0.226 to 1.621; p = 0.009). However, the complete fixed-roller model had an adjusted R² of only 0.022, indicating very limited explanatory performance after accounting for model complexity. Cranial anthropometry showed no robust association with either laboratory task-performance outcome. The only crude cranial signal was not supported by the adjusted or sensitivity analyses. Pull-up performance showed a modest exploratory association with fixed-roller task performance, but the low adjusted R² of the overall model precludes claims of strong explanatory or predictive importance. This finding requires replication in an independent sample. These findings are restricted to the laboratory performance tasks examined and provide no evidence regarding physiological or operational − Gz tolerance.