Three dimensional multi-segmental trunk kinematics and kinetics during gait: Test-retest reliability and minimal detectable change

•Varied reliability indices for trunk kinematics and kinetics in 3DGA.•Trunk sagittal plane joint angles and moments were the most reliable parameters.•Trunk rotation joint angles showed less reliability and agreement.•Multi-segmental trunk allows a more detailed comparison with pathological groups.•Results showed the potential importance of trunk data for clinical reasoning.

Background and AimTrunk kinematics and kinetics can contribute to more detailed information on gait impairment, however, data about reliability and measurement error of multi-segment trunk on three-dimensional gait analysis (3DGA) is lacking. The aim of this study is to investigate test-retest reliability and MDC of 3DGA kinematic and kinetic data in a sample of healthy individuals, using a two rigid segment model for the trunk.MethodsA test-retest study with a median interval of 7 days and a sample of 23 healthy individuals was conducted. Anthropometric, time-distance parameters and peak values for lower limb and trunk joint angles/moments were computed. The intraclass correlation coefficient (ICC3,k), standard error of measurement (SEM), minimal detectable change (MDC) and 95% limits of agreement (LOA) were calculated.ResultsWe found acceptable test-retest reliability for most joint angles and a SEM ≤4°. The ICCs were above 0.7 for joint moments and the SEM and MDC were ≤0.2 Nm/kg and ≤0.6 Nm/kg, respectively. Bland-Altman plots with 95% LOA revealed a good agreement and time-distance parameters were all highly repeatable (majority ICCs > 0.90).ConclusionsThe results of this study suggest varied reliability indices for multi-segment trunk joint angles and moments during gait and an acceptable level of error, particularly for sagittal plane parameters. Some parameters showed wide 95% CIs for ICCs and higher SEM%. However, we believe that this study provides preliminary data regarding reliability indices for multi-segment trunk during gait, which may be valuable for clinical reasoning and decision making when dealing with movement disorders.