Landing stability in anterior cruciate ligament deficient versus healthy individuals: A motor control approach

Objectives To compare the temporal effectiveness of landing strategies in anterior cruciate ligament deficient (ACLD) versus non-injured participants, when they landed on one leg after running or after a single leg hop. Design Case control study. Setting Laboratory setting. Participants Participants were 30 ACLD patients and 30 control subjects. Main outcome measures Time to stabilise (TTS) was measured using centre of pressure (COP), horizontal (Fy) and vertical (Fz) force velocity on a Kistler forceplate. Kinematic data were collected using a Vicon 512 system with 8 IR cameras. Between group differences were analysed using a two-way ANOVA with post hoc t-tests. Results Significant group differences were found in running speed, hop distance, failed attempts, deceleration, and TTS using COP velocity in both activities. Conclusions When required to stop and balance on their injured leg, ACLD participants selected slower running speeds and less hop distance to succeed from than did controls, and they used different strategies to stabilise upon landing. They also showed a significantly poorer ability to maintain stable stance following deceleration. ACLD individuals who were able to adapt with some success did so by increasing the time available to them and limiting function to within the boundaries they can control effectively