Methods / Statistics

Document Type



This study compared typical measures of knee joint moment, angle and stiffness in eight recreational runners during distance running after digitally filtering ground contact force and lower limb motion data using 20-20 Hz and 50-8 Hz cut-off frequencies, respectively. The matched 20 Hz approach clearly removed some higher frequency oscillation signals in the knee moment curves and produced a better linear regression fit to calculate joint stiffness from the knee moment-angle relationship. However, knee joint stiffness values over the first half of running stance were no different between the two filtering approaches. It remains to be determined whether improved linear fit can lead to greater sensitivity in the joint stiffness estimations to detect changes that may result from factors such as fatigue or footwear interventions.