Analysis of sit-ski alpine skiing trajectories based on an inverted pendulum model

Abstract

Abstract This study analyzes sit-ski alpine skiing trajectories during gate-turning phases using an inverted pendulum model combined with an advanced kinematic testing system involving inertial sensors and drone video analysis. Data were collected from 11 elite sit-ski athletes during runs on a designated slope segment. The inertial sensor system showed static accuracy of 2° and an average deviation of 0.008 m, while drone video analysis had a mean relative error of 1.36% ± 0.94%. Analysis of 33 gate turns revealed a mean skiing distance of 13.61 ± 2.87 m and mean time of 0.88 ± 0.19 s, with significant positive correlation ( $$\:p$$ < 0.05) between single-gate skiing time ( $${\it\text{t}}_{\text{s}}$$ ) and the minimum distance ( $${\it\text{d}}_{\text{m}\text{i}\text{n}}$$ ) ( $$\:\rho\:$$ = 0.74, $$\:p$$ < 0.01) and lateral distance ( $${\it\text{d}}_{\text{l}\text{e}\text{v}}$$ ) ( $$\:\rho\:$$ = 0.73, $$\:p$$ = 0.01). Simulation with the inverted pendulum model yielded a COM trajectory length of 97.93 ± 2.31 m, 1.66 ± 3.61 m shorter than actual values ( $$\:p$$ = 0.16), and a simulated time of 6.36 ± 0.64 s, showing strong consistency (ICC = 0.85 for time, ICC = 0.45 for trajectory length). These results confirm that optimizing the balance of turning radius, speed, and distance reduces skiing time, supporting the model’s effectiveness in individualizing trajectory optimization for sit-ski alpine skiing.