Gait analysis is used in clinical research to evaluate lower extremity movement patterns associated with walking. Foot strike and toe-off angles are key kinematic variables that reflect ability to avoid obstacles across walking environments. While overground walking is considered the clinical gold standard, laboratory gait analyses approaches vary between overground and treadmill surfaces. Further, clinical gait analyses are typically completed via subjective observation, while the laboratory gold standard is with optical motion capture. The purpose of this study was to compare foot strike and toe-off angles during overground and treadmill surfaces to determine if ankle gait kinematics are similar between treadmill and overground surfaces. 

Participants completed an overground and treadmill walking condition. Bilateral averaged ankle  foot strike and toe-off angles were calculated across the full walking condition. Intraclass correlation coefficients (ICC) were computed to assess measurement reliability between surfaces.

Results indicated that foot strike angles were larger for overground walking (L: 29.07°±3.72, R: 28.29°±5.12) than for treadmill walking (L: 25.15°±4.22, R: 24.80°±4.40). Similarly, toe-off angles were larger overground (L: 40.12°±3.87, R: 40.96°±2.94) than on the treadmill (L: 38.18°±4.73, R: 39.35°±4.13). Statistical analysis revealed an ICC of 0.928 (LB CI: -0.015, UB CI: 0.995), indicating a measurement validity rating of ‘excellent’. These findings suggest small but consistent kinematic differences between walking environments.

Consistent with previous research (Riley et al., 2007), treadmill walking produces gait mechanics that are comparable to overground walking, though minor differences in joint angle approximations may occur. Clinically, this supports the use of published treadmill-based ankle kinematics for clinical comparison.