Background and Aim: Anterior cruciate ligament (ACL) injury is common in sports competition and training. Following ACL rupture, neuromuscular system performance is disrupted. Perturbation training can improve the function of patients with ACL reconstruction. The aim of the present study was to assess the effects of perturbation training on ground reaction force and functional status of these patients .

Materials and Methods: Twenty patients with ACL reconstruction were randomly assigned into intervention (mean age: 24/2 ±3/4 years) and control (mean age: 27/1 ± 2/5 years) groups. The intervention group performed ten sessions perturbation training with rocker board, wobble board and Bosu. Peak vertical ground reaction force (GRF) and time to peak vertical GRF were recorded by KISTLER force plate during single leg landing from a 30cm height step. In addition, cross hop test also was evaluated as a functional test.

Results: Before perturbation training, both GRF and time to peak vertical GRF in reconstructed knee had not significant difference between two groups (P>0/05). In addition, functional test score had not significant difference between the groups (P=0/62). Following perturbation training, peak vertical GRF in reconstructed knee was greater than that in control groups (P<0/003).Although time to peak vertical GRF in reconstructed knee increased, there was not statistically significant difference between two groups (P=0/50). Furthermore, functional test score was statistically greater in intervention group (P=0/03).

Conclusion: This s tudy showed that perturbation training can improve functional status in patients with ACL reconstruction. In addition, force plate findings indicated that the patients tolerated more forces at longer time in single leg landing.

Key words: Perturbation training, Ground reaction force, ACL reconstruction, Function