Introduction: In health monitoring and biotelemetry, the real-time recording of ground reaction forces under each foot during gait has a large potential for the automatic detection of abnormal posture, falling prevention, etc. at home or in public places. For this, mounting a large force platform on/in the ground ensures to record data for numerous footsteps while avoiding the step 'targeting' problem. Davis and Cavanagh (1993) have proposed a solution using a large force plate but several points of Davis and Cavanagh's method remain unclear and hardly computable. Objective: Develop a method that decomposes left and right GRF profiles from the GRF profile recorded on a single platform. This method aims to include a systematic detection of the single to double stand-phase-instants in order to lead to accurate measurement of the total GRF component in typically developing children. Methods: Six children were asked to walk without targeting their footsteps on a set-up composed of independent force platforms. The total GRF component, independently measured on the different platforms, was numerically summed to obtain the corresponding global total GRF, to which the decomposition method was applied. Then, the validation consisted in comparing the total GRF computed from this decomposition to the independently measured total GRF. Results: The mean relative error between the computed total GRF and the corresponding measured vertical GRF of 36 double stances (6 double stances × 6 children) is equal to 3.8±2.6%. Conclusion: We have implemented an innovative method to assess with accuracy the vertical GRF component under each foot using a unique large force platform. This leads to large perspectives in health monitoring and biotelemetry.

The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons should be designed to ease the movement of people with physical shortcoming, their design is generally based on data obtained from healthy adults, which leads to oversized components that are inadequate to the targeted users. Consequently, the objective of this study is to custom-size the lower limb exoskeleton actuators based on dynamic modeling of the human body for children with CP on the basis of hip, knee, and ankle joint kinematics and dynamics of human body during gait. For this purpose, a multibody modeling of the human body of 3 typically developed children (TD) and 3 children with CP is used. The results show significant differences in gait patterns especially in knee and ankle with respectively 0.39 and -0.33 (Nm/kg) maximum torque differences between TD children and children with CP. This study provides the recommendations to support the design of actuators to normalize the movement of children with CP.

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