There are multiple definitions:

1. free wall strain(English)

   • calculated by averaging the values obtained from the three free wall segments as recommended in the joint consensus document issued by the ASE/EACVI/Industry Task Force, and expressed as percentage. Has been proposed as an accurate and sensitive measure of right ventricular function that could integrate other conventional parameters such as tricuspid annulus plane systolic excursion and fractional area change
   • FWRVLS, GLS, FAC, RV, TAPSE
   • Cardiology, Ratio-based metric
   • https://doi.org…93/ehjci/jez246

2. fast walking speed(English)

   • may refer to cortical activity during walking with aging
   • DT, oxyHb, SSWS, ST
   • Musculoskeletal system, Brain (dys)function, Aging
   • https://doi.org…rainsci11121551