Inertial sensor based reference gait data for healthy subjects

Inertial sensor gait analysis systems (ISGAS) facilitate gait analysis in an unobstructed environment outdoors or outside of a conventional gait laboratory. However, their use in clinical settings and in large scale studies necessitates thorough evaluation of their performance in different settings and populations and reference data on healthy subjects. The purposes of this study were to obtain spatio-temporal gait parameters using a large cohort of subjects of all ages and to identify relationships between gait parameters and subject characteristics. An inertial sensor based system (RehaWatch(®), HASOMED(®)) was used to collect gait data for 1860 healthy subjects (919 men; aged 5-100 years). Following two practice trials, data of one trial were collected for each subject while walking on a 20m walkway. Spatio-temporal gait parameters were calculated and normalized to body height. Demographic and morphological data including age, gender, body height and body mass were recorded. Multifactorial regression models were used to evaluate determinants of different gait parameters. Strong non-linear relationships between predictors (age) and gait parameters were identified. Overall, the predictors explained the largest portion of variance for stride length (R(2)=0.46). Normalized cadence showed one peak across all ages. Normalized walking speed and normalized stride length showed two peaks across all ages. The largest and smallest variations across the ages were observed for normalized walking speed (98%) and for normalized stride length (89%), respectively. This reference database is the foundation for future evaluations of gait disorders in patients of all ages and has been integrated in the RehaWatch(®) system.