The effect of open kinetic chain knee extensor resistance training at different training loads on anterior knee laxity in the uninjured

• Evaluated extensor open kinetic chain resistance training on anterior laxity in knee.
• Laxity increased in the high load (2 repetition maximum (RM)) isotonic group.
• Laxity unchanged in the other 2 groups (isotonic 20RM and isokinetic).

BackgroundThe commonly used open kinetic chain knee extensor (OKCKE) exercise loads the sagittal restraints to knee anterior tibial translation.ObjectiveTo investigate the effect of different loads of OKCKE resistance training on anterior knee laxity (AKL) in the uninjured knee.Study designnon-clinical trial.MethodsRandomization into one of three supervised training groups occurred with training 3 times per week for 12 weeks. Subjects in the LOW and HIGH groups performed OKCKE resistance training at loads of 2 sets of 20 repetition maximum (RM) and 20 sets of 2RM, respectively. Subjects in the isokinetic training group (ISOK) performed isokinetic OKCKE resistance training using 2 sets of 20 maximal efforts. AKL was measured using the KT2000 arthrometer with concurrent measurement of lateral hamstrings muscle activity at baseline, 6 weeks and 12 weeks.ResultsTwenty six subjects participated (LOW n = 9, HIGH n = 10, ISOK n = 7). The main finding from this study is that a 12-week OKCKE resistance training programme at loads of 20 sets of 2RM, leads to an increase in manual maximal AKL.ConclusionsOKCKE resistance training at high loads (20 sets of 2RM) increases AKL while low load OKCKE resistance training (2 sets of 20RM) and isokinetic OKCKE resistance training at 2 sets of 20RM does not.