The study design corresponded to a two-way variance analysis with three groups and 4 examination times (Baseline, 6 weeks, 12 weeks and 24 weeks post ACL reconstruction). The level of significance was set at 5%. The key indicators of the quadriceps muscle training intervention were the isokinetic strength development of the extensors of the injured leg at 90 degrees/second and 180 degrees/second and the distance achieved by participants performing the single-leg hop and the time to complete the shuttle run. The target was to show a difference of 10% in the relative distance jumped for the single-leg hop and for the isokinetic strength tests and a 1.2 second difference in the time to complete the shuttle run. The target of 3 weeks was set for participants to achieve full weight-bearing capability without use of a walking aid. A comparison between the groups of the time for return to usual work activities was planned.