OBJECTIVES: Climbing stairs is one of the challenging activities for elderly and pathological individuals; because it is associated with higher force compared with walking on-level. However, the repeatability of the ground reaction force (GRF) during ascending and descending has not been measured accurately.

METHODS: 10 healthy participants (five females and five males, 32.1 ± 6.8 years, mass 69.3 ± 10.5 kg) participated in this study by climbing three-step stair at the university of Salford clinical gait analysis laboratory, UK. Each participant were asked to ascent and descent the stair with using control shoes. Five good trails was complete by each participant. The GRF was measured using two embedded platforms. The Interclass Correlation Coefficients (ICC) and the standard error of measurement (SEM) were calculated.

RESULTS: During stairs ascending, the average of the first peak of the GRF was 1.05±0.06 Newton (N) and the second peak was 1.04±0.06 N. The ICCs of the first peak and the second peak were 0.94 N and SEM was up to 0.02 N. During stair descending, the average of the first peak of the GRF was 1.17±0.16 N and the second peak was 0.96±0.06 N. ICC of the first peak was 0.93 N and the ICC of the second peak was 0.83 N and SEM was up to 0.05 N.

CONCLUSIONS: The repeatability of the ground reaction force is high according to the Fleiss' classifications with minimum measurement error. This results could be used as a baseline during evaluating pathological individuals during stair climbing with different interventions and orthotics.