Estimating Youth Locomotion Ground Reaction Forces Using an Accelerometer-Based Activity Monitor

Abstract

To address a variety of questions pertaining to the interactions between physical activity, musculoskeletal loading and musculoskeletal health/injury/adaptation, simple methods are needed to quantify, outside a laboratory setting, the forces acting on the human body during daily activities. The purpose of this study was to develop a statistically based model to estimate peak vertical ground reaction force (pVGRF) during youth gait. 20 girls (10.9±0.9 years) and 15 boys (12.5±0.6 years) wore a Biotrainer AM over their right hip. Six walking and six running trials were completed after a standard warm-up. Average AM intensity (g) and pVGRF (N) during stance were determined. Repeated measures mixed effects regression models to estimate pVGRF from Biotrainer activity monitor acceleration in youth (girls 10–12, boys 12–14 years) while walking and running were developed. Log transformed pVGRF had a statistically significant relationship with activity monitor acceleration, centered mass, sex (girl), type of locomotion (run), and locomotion type-acceleration interaction controlling for subject as a random effect. A generalized regression model without subject specific random effects was also developed. The average absolute differences between the actual and predicted pVGRF were 5.2% (1.6% standard deviation) and 9% (4.2% standard deviation) using the mixed and generalized models, respectively. The results of this study support the use of estimating pVGRF from hip acceleration using a mixed model regression equation.

Assessment of Gait Kinetics Using Triaxial Accelerometers

“…As previous studies have demonstrated positive correlations peak vertical and resultant GRF and LR with waist, thigh, and tibia accelerations 4–7 and the ankle is closest in location to ground contact, we hypothesized that ankle accelerations would have higher positive correlations than waist, thigh, or tibia accelerations.…”

“…A small number of studies have shown positive correlations of peak accelerations, measured with body-worn accelerometers, with peak vertical and resultant GRF and LR in both adults 4–6 and children. 7 However, these studies used accelerometers placed on the hip, thigh, tibia, and/or wrist but did not investigate the relationship of ankle accelerations with peak GRF and LR. Since peak LR is a key indicator of loading underfoot 8 and the ankle is closer in location to ground contact, ankle peak accelerations may provide higher correlations with peak GRF and LR.…”

“…Previous studies have not investigated a wide range of gait velocities or gait velocities less than 0.67 m/s. 4–6,9,10 Normal gait velocities of less than 0.69 m/s have been characterized as a risk factor for fractures. 11 …”

Wearable Sensing for Solid Biomechanics

“…Both Lo et al [109] and Neugebauer et al [117] propose to further simplify kinetic analysis using micro-inertial sensors for GRF measurement. Although GRF is critically important for kinetics analysis, it can only be used to infer virtual force generated at each joint by inverse dynamics, which may not be enough in practice.…”

“…A relatively high sensitivity and specificity of 88% and 83%, respectively, were achieved for detecting pressure transitions, and a specificity of 77% was achieved for detecting medial and lateral contact. Similarly, Neugebauer et al [117] used a waist-worn accelerometer to estimate GRF. A mixed effect and generalised regression model, which is not subject specific, is used to predict the peak vertical GRF from the waist-worn sensor.…”