Acute effects of preventive warm-up exercises on modifiable risk factors for anterior cruciate ligament injuries: a three-arm randomized-controlled crossover trial.

Abstract

We aimed to compare the potential acute effects of single bouts of a classic prevention and a risk factor-focus training aiming to target modifiable anterior cruciate ligament (ACL) rupture risk factors and the impact of neuromuscular fatigue on relevant ACL rupture risk factors. Two preventive warm-up (standard and ACL rupture risk factor training) and one inactive arm were compared; each of these were followed by a standardized neuromuscular fatigue protocol. The assessments included two Trail making tests (TMT-A; TMT-B, time to complete), drop jump landings (knee separation distance, normalized at hip width), as well as unanticipated counter movement jump landings (time to stabilization and peak ground reaction force). We included 18 participants (25±2years). No differences were found between times and conditions for TMT (P>0.05). A significant time effect occurred in time to stabilization (F=2.6; P<0.05) and a significant time*baseline-value*jumping time interaction was seen in peak ground reaction force (F=3.1; P<0.05). No time effect was found for any knee separation distance (F=.1-2.4; P>0.05); but a significant time*baseline-value*jumping time interaction was seen at initial ground contact (F=2.8; P<0.05), and lowest point (F=4.2; P<0.01). Risk factor-focus and classic warm-up may not differ in their acute effects on modifiable functional ACL (re-)injury risks factors.