Background: Two-stairway designs: force plate integrated stairway (FPIS) and force plates attachable interlaced stairway (FPAIS), have been used in gait laboratories in order to distinguish stair gait patterns between healthy and pathological groups and to assess the efficacy of different interventions for pathological groups especially with knee injuries. The previous studies evaluated the knee joint repeatability during stair climbing using FPIS design without evaluation the measurement error. Therefore, this study looked at the test and re-test repeatability of knee joint kinematics and kinetics in the sagittal; frontal; transverse planes during FPAIS stair climbing with measurement error calculation.
Method: Ten healthy (32.1 ± 6.8 years, five male, and five female) participants performed walking tests on the three stairs in two different sessions within a week.
Findings: The results showed high ICC’s for angles (ICC’s 0.83-0.99), and moments (ICC's 0.75-0.99). The SEM were up to 2.7° and 0.3 nm/kg and the RMSD were up to 4.1 ± 2.4° and 0.14 ± 0.10 nm/kg. Thus, reliability of the data showed moderate to excellent within healthy individuals. This result could provide an accurate baseline for pathological group in future studies which examines the orthotics impacts on knee joint kinematics and kinetics.