Real-Time Gait Event Detection Based on Kinematic Data Coupled to a Biomechanical Model

Real-time detection of multiple stance events, more specifically initial contact (IC), foot flat (FF), heel off (HO), and toe off (TO), could greatly benefit neurorobotic (NR) and neuroprosthetic (NP) control. Three real-time threshold-based algorithms have been developed, detecting the aforementioned events based on kinematic data in combination with a biomechanical model. Data from seven subjects walking at three speeds on an instrumented treadmill were used to validate the presented algorithms, accumulating to a total of 558 steps. The reference for the gait events was obtained using marker and force plate data. All algorithms had excellent precision and no false positives were observed. Timing delays of the presented algorithms were similar to current state of the art algorithms for the detection of IC and TO, whereas smaller delays were achieved for the detection of FF. Our results indicate that, based on their high precision and low delays, these algorithms can be used for the control of a NR/NP, with exception of the HO event. Kinematic data is used in most NR/NP control schemes and thus available at no additional cost, resulting in a minimal computational burden. The presented methods can also be applied for screening pathological gait or in general gait analysis in/outside of the laboratory.