A few studies concerning the improvement of quadriceps muscle strength deficit (QD)
at an early stage following anterior cruciate ligament (ACL) reconstruction have been
conducted whereas, ACL rehabilitation protocols based on contralateral quadriceps
strength (QS) do not exist. Given these, the goals of our study were (1) to evaluate the
effects of cross-eccentric exercise (CEE) on QD on ACL reconstructed knees, and (2) to
explore any changes in QD following CEE provided at the frequencies of 3 or 5 times per
week. For this study, 42 ACL-reconstructed patients were randomly assigned into
3 groups, two experimental and one control and followed an 8-week rehabilitation
program. Additionally, the experimental groups received CEE for 3 and 5 days per week
for 8 weeks in their uninjured knees. QS was evaluated with an isokinetic/isometric test,
at 60 degrees of knee flexion of both limbs before and after completion of CEE. Twofactor
ANOVA showed a significant improvement of QD between groups (F ¼ 5.16,
p ¼ 0.01) after CEE completion on ACL reconstructed knees. Statistically significant
results arose from the 3 days per week (D ¼ 18.60, p ¼ 0.01) and 5 days per week
(D ¼ 15.12, p ¼ 0.04) experimental groups, whereas the control group did not yield
any statistically significant differences. CEE used as an adjunct to the ACL traditional
rehabilitation program at the weekly frequencies of 3 and 5 times at the early stage of
reconstruction significantly improved QD.