Marx Activity Rating Scale

The Marx Activity Rating Scale (MARS) is a 4-item patient-reported instrument that quantifies the frequency of high-demand athletic activities performed in the past four weeks. Developed by Marx and colleagues in 2001 and published in the American Journal of Sports Medicine, the MARS focuses specifically on quantifying participation in running, cutting, decelerating, and pivoting—the high-impact, multi-directional activities that demand the most from the knee and ankle. The MARS is widely used in orthopedic research to classify patients by activity level and to assess return to activity following surgery.