LAUSR

BACKGROUND Studies on the sensory perception of mass mostly focus on the hands rather than the feet. The aim of our study is to measure how accurately runners can perceive additional shoe mass in comparison to a control shoe (CS) while running, and moreover, whether there is a learning effect in the perception of mass. Indoor running shoes were categorized as a CS (283 g) and shoes with four additional masses: shoe 2 (+50 g), shoe 3 (+150 g), shoe 4 (+250 g), and shoe 5 (+315 g). METHODS There were 22 participants in the experiment, which was divided into two sessions. In session 1, participants ran on a treadmill for 2 min with the CS and then put on one set of weighted shoes and ran for another 2 min at a preferred velocity. A binary question was used after the pair test. This process was repeated for all the shoes to compare them with the CS. RESULTS Based on our statistical analysis (mixed effect logistic regression), the independent variable (ie, mass) did have a significant effect on perceived mass (F4,193 = 10.66, P < .0001), whereas repeating the task did not show a significant learning effect (F1,193 = 1.06, P = .30). CONCLUSIONS An increase of 150 g is the just-noticeable difference among other weighted shoes and the Weber fraction is equal to 0.53 (150:283 g). Learning effect did not improve by repeating the task in two sessions in the same day. This study facilitates our understanding about sense of force and enhances multibody simulation in running.