From the study:
Abstract
A safe rehabilitation exercise for anterior cruciate ligament (ACL) injuries needs to be compatible with the normal knee arthrokinematics to avoid abnormal loading on the joint structures. The objective of this study was to measure the amount of the anterior tibial translation (ATT) of the ACL-deficient knees during selective open and closed kinetic chain exercises. The intact and injured knees of fourteen male subjects with unilateral ACL injury were imaged using uniplanar fluoroscopy, while the subjects performed forward lunge and unloaded/loaded open kinetic knee extension exercises. The ATTs were measured from fluoroscopic images, as the distance between the tibial and femoral reference points, at seven knee flexion angles, from 0° to 90°. No significant differences were found between the ATTs of the ACL-deficient and intact knees at all flexion angles during forward lunge and unloaded open kinetic knee extension (P < 0.05). During loaded open kinetic knee extension, however, the ATTs of the ACL deficient knees were significantly larger than those of the intact knees at 0° (P = 0.002) and 15° (P = 0.012). It was suggested that the forward lunge, as a weight-bearing closed kinetic chain exercise, provides a safer approach for developing muscle strength and functional stability in rehabilitation program of ACL-deficient knees, in comparison with open kinetic knee extension exercise.
Chad’s comments:
This one is interesting for a few reasons. First they did real time fluoroscopy on ACL deficient and normal knees so they could see exactly what’s happening during the exercise. Lunges came out looking particularly good, making them a good choice for post-op ACL reconstruction, as opposed to other research on wall squats. In my opinion, and the opinion of most weightlifters and strength and conditioning specialists, lunges are more functional. It makes you wonder why so many physical therapist like wall squats so much. It’s probably because most physical therapists, despite their schooling, do not have good backgrounds in strength and conditioning.
What was also interesting was they found no anterior tibial translation with leg extensions without resistance, but they did when they added a load, and in the study that load was 2 kg. It would be interesting to see the study repeated with greater than 10 kg, as other research found that increased training loads on leg extensions were associated with decreased anterior tibial translation. However, that was measured after 6 weeks of training, rather than in real time as in this study.
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