The Utility of a High-intensity Exercise Protocol to Prospectively Assess ACL Injury Risk

This study investigated the utility of a 5-min high-intensity exercise protocol (SAFT(5)) to include in prospective cohort studies investigating ACL injury risk. 15 active females were tested on 2 occasions during which their non-dominant leg was analysed before SAFT(5) (PRE), immediately after (POST0), 15 min after (POST15), and 30 min after (POST30). On the first occasion, testing included 5 maximum isokinetic contractions for eccentric and concentric hamstring and concentric quadriceps and on the second occasion, 3 trials of 2 landing tasks (i. e., single-leg hop and drop vertical jump) were conducted. Results showed a reduced eccentric hamstring peak torque at POST0, POST15 and POST30 (p<0.05) and a reduced functional HQ ratio (Hecc/Qcon) at POST15 and POST30 (p<0.05). Additionally, a more extended knee angle at POST30 (p<0.05) and increased knee internal rotation angle at POST0 and POST15 (p<0.05) were found in a single-leg hop. SAFT(5) altered landing strategies associated with increased ACL injury risk and similar to observations from match simulations. Our findings therefore support the utility of a high-intensity exercise protocol such as SAFT(5) to strengthen injury screening tests and to include in prospective cohort studies where time constraints apply.