Evaluation of Isokinetic and Isometric Strength Measures for Monitoring Muscle Function Recovery After Anterior Cruciate Ligament Reconstruction

Abstract

Although various strength tests and their outcome measures have been proposed for anterior cruciate ligament (ACL) reconstruction (ACLR), their measurement properties still remain relatively underexplored. The aim of this study was to investigate the longitudinal construct validity of the standard isokinetic (IKT) and isometric test (IMT), and of the IMT of alternating consecutive maximal contractions (ACMC). In addition, the concurrent validity of ACMC was assessed and compared with the validity of IMT. The strength of quadriceps and hamstrings in 20 male athletes with an anterior cruciate ligament (ACL) injury were assessed before ACLR, 4 and 6 months after ACLR, by means of IMT, ACMC, and IKT performed at 60 and 180° · s(-1). Significant between-session differences in muscle strength variables were found in the involved quadriceps (F > 6.5; p ≤ 0.05), but not in the uninvolved leg (F < 2.5; p > 0.05). Coefficients of variations in the uninvolved leg (all below 13.5%) were lower than the involved leg (11.7-22.1%). Intraclass correlation coefficients were moderate-to-high for the uninvolved leg and low-to-high for quadriceps of the involved leg. The concurrent validity of ACMC with respect to the IKT (r = 0.57-0.92; p ≤ 0.05) was comparable with the validity of IMT (r = 0.52-0.87; p ≤ 0.05). We conclude that the explored longitudinal construct validity of most of the evaluated variables could be sufficiently sensitive to detect the effects of the applied rehabilitation procedures. In addition, the obtained sensitivity and concurrent validity and the potential advantages of ACMC over IMT, all suggest that ACMC could be a particularly promising method for routine testing of neuromuscular function after ACLR.

The effect of anterior cruciate ligament reconstruction on hamstring and quadriceps muscle function outcome ratios in male athletes

“…The axis of rotation of the dynamometer was aligned with the lateral femoral epicondyle. The knee angle was fixed at 45 degrees in flexion [17,18]. Afterwards, a set of two submaximal contraction pre-tests were performed for each muscle group in the dynamometer.…”

Asymmetries in explosive strength following anterior cruciate ligament reconstruction

“…The uninvolved leg was always tested first. A real time visual feedback of the force-time curve was available during the assessment of the maximum isometric strength [19, 41]. The same experienced test leader supervised all the tests.…”

Countermovement Jump and Isokinetic Dynamometry as Measures of Rehabilitation Status After Anterior Cruciate Ligament Reconstruction

“…11 As such, the value of the ISO test might be limited because its single-plane nature is contrary to movements in field sports, which are commonly multidirectional and require the simultaneous coordination of multiple joints in multiple planes. 12 Power production as measured during a jumping task is a key measure of athleticism, especially in multidirectional sports. 13 Variables that capture the interaction of joints (eg, percentage of power generation contribution at each joint) during jumping or landing may be better measures for assessing the status of rehabilitation, 9,[14][15][16][17][18] as these can identify adaptations in the limbs and joints and interdependent relationships during functional tasks after ACLR.…”