Sport, Landing, Cartilage, MRI, Attentional Focus

T2 relaxation time reflects cartilage compressive loading, with more acute changes in T2 relaxation time indicative of greater impact forces which may lead to greater risk of degeneration of cartilage. As such, the present study examined acute changes in T2 relaxation time of the femoral lateral cartilage under different attentional focus instructions during repeated drop landings. It was hypothesized that external focus (EF) instructions (focus on landing as soft as possible) would improve landing biomechanics resulting in less acute changes in T2 relaxation time relative to internal focus (IF) instructions (focus on bending your knees when you land) and a no-focus control condition (CON). Ten healthy women (Mage = 20.4 ± 0.8 years) performed the drop landing task from a 50cm high box over the course of three days (N = 150 total, n = 50 each day). For each day, the participants performed the task under one of the three counter-balanced attentional focus conditions (EF, IF, and CON). Magnetic resonance imaging (MRI) using T2 mapping was performed on knee cartilage before and after completing the drop landings each day. In total, 180 cartilage slices were measured on a 1.5T MRI and were manually segmented and divided into regions of interest. Results indicated significant reductions in T2 relaxation time in the femur, anterior femur, central femur, anterior part of the central femur, and anterior part of the posterior femur in the CON condition (all p’s < .05), and similar reductions in the IF condition. Importantly, no significant reductions in T2 relaxation time of cartilage was found during the EF condition suggesting lower loading of femoral lateral cartilage. Findings suggest that adopting an external focus of attention may help reduce frequent landing impact forces, thereby reducing the risk for osteoarthritis and cartilage degeneration.