Effect of cross exercise on quadriceps acceleration reaction time and subjective scores (Lysholm questionnaire) following anterior cruciate ligament reconstruction

BACKGROUND Anterior cruciate ligament (ACL) injury or reconstruction can cause knee impairments and disability. Knee impairments are related to quadriceps performance - accelerated reaction time (ART) - and disability to performance of daily living activities which is assessed by questionnaires such as the Lysholm knee score. The purposes of this study were to investigate the effect of cross exercise, as supplementary rehabilitation to the early phase of ACL reconstruction: a) on quadriceps ART at the angles 45 degrees , 60 degrees and 90 degrees of knee flexion and, b) on the subjective scores of disability in ACL reconstructed patients. METHODS 42 patients who underwent ACL reconstruction were randomly divided into 3 groups, two experimental and one control. All groups followed the same rehabilitation program. The experimental groups followed 8 weeks of cross eccentric exercise (CEE) on the uninjured knee; 3 d/w, and 5 d/w respectively.Quadriceps ART was measured at 45 degrees , 60 degrees and 90 degrees of knee flexion pre and nine weeks post-operatively using an isokinetic dynamometer. Patients also completed pre and post operatively the Lysholm questionnaire whereby subjective scores were recorded. RESULTS Two factor ANOVA showed significant differences in ART at 90 degrees among the groups (F = 4.29, p = 0.02, p < 0.05). Post hoc Tukey HSD analysis determined that the significant results arose from the first experimental group in comparison to the control (D = -0.83, p = 0.01). No significant differences were revealed at 45 degrees and 60 degrees .Significant differences were also found in the Lysholm score among the groups (F = 4.75, p = 0.01, p < 0.05). Post hoc analysis determined that the above significant results arose from the first experimental group in comparison with the control (D = 7.5, p < 0.01) and from the second experimental in comparison with the control (D = 3.78, p = 0.03). CONCLUSION CEE showed improvements on quadriceps ART at 90 degrees at a sequence of 3 d/w and in the Lysholm score at a sequence of 3 d/w and 5 d/w respectively on ACL reconstructed patients.