Objectively Measured Physical Activity in Patients after ACL Reconstruction

Abstract

Return to a healthy level of physical activity is a common clinical goal for patients recovering from anterior cruciate ligament reconstruction (ACLR). Objective measures of physical activity may provide useful information regarding achievement of rehabilitation goals in patients with ACLR. PURPOSE: To investigate differences in the average minutes per day (min/day) spent in moderate-to-vigorous physical activity (MVPA) as well as the total number of steps per day (steps/day) between individuals with ACLR and matched controls. A second purpose was to investigate relationships between MVPA and steps/day subjective activity scales Tegner and Marx activity scales. METHODS: Physical activity was assessed using ActiGraph accelerometers in 33 participants (22 females; 20.3±1.8 years; 171.8±10.5cm; 69.9±11.3kg; 27.8±17.5 months from surgery) with a history of primary unilateral or bilateral ACLR as well as 33 healthy controls (CON) (20.8±1.6 years; 172.9±8.5cm; 70.2±13.5kg) (matched on age, sex, and Tegner activity level). Participants wore the accelerometer for 7 consecutive days and completed the IKDC 2000 subjective form and the Tegner and Marx activity scales. Independent t-tests were used to examine between group differences. Bivariate correlation coefficients were calculated between objective and subjective activity levels. RESULTS: Patients with ACLR participated in less MVPA per day (ACLR: 78.3±26.6 min/day; CON: 94.2±26.6 min/day; P=0.02) and less steps/day (ACLR: 7,982±3,020 steps/day; CON: 9,945±2,885 steps/day; P=0.02) compared to healthy matched controls. Only 25% of participants with ACLR met the 10,000 steps/day guidelines compared to 42% of controls. However, Marx (ACLR: 10.2±4.8; CON: 10.8±3.8; P=0.63) and Tegner (ACLR: 6.2±2.1; CON: 6.7±1.7; P=0.11) activity levels did not differ between groups. No relationships were observed between objectively measured physical activity and scale measures (P>0.05). CONCLUSIONS: Patients with ACLR accumulate less MVPA and fewer steps/day compared to highly matched controls despite reporting similar subjective activity levels. These findings highlight the importance of objective monitoring of physical activity level following return to activity due to the potential risk associated with reduced levels of physical activity.