Fig. 4.

Variation of the relative error as a function of duration of locomotion periods: a), b) cadence measured in time domain from sensor on chest and L5, respectively; c), d) cadence estimated in time domain from sensor on chest and L5, respectively. The abrupt decrease of the error for locomotion periods longer than approximately 20 s, and the steadiness after, indicate that the longer periods, who are likely to correspond to purposeful locomotion, are more reliable for the assessment of the gait pattern in every-day life conditions