No Association Between Injury-Related Fear and Isokinetic Quadriceps Strength in Individuals With a History of Anterior Cruciate Ligament Reconstruction

Context: Injury-related fear and quadriceps strength are independently associated with secondary anterior cruciate ligament (ACL) injury risk. It is not known whether injury-related fear and quadriceps strength are associated, despite their individual predictive capabilities of secondary ACL injury. The purpose of this study was to examine the association between injury-related fear and quadriceps strength in individuals at least 1 year after ACL reconstruction (ACLR). Design: Cross-sectional study. Methods: Forty participants between the ages of 18 and 35 years at least 1 year post unilateral primary ACLR. Participants completed the Tampa Scale of Kinesiophobia-11 (TSK-11) and a standard isokinetic quadriceps strength assessment using the Biodex Isokinetic Dynamometer. Pearson Product-Moment correlations were used to examine the linear association between the TSK-11 scores and peak torque (in nanometers per kilogram) for each limb and between the TSK-11 scores and limb symmetry indices for each limb. Pearson Product-Moment correlation coefficients (r) were interpreted as very high (.90–1.00), high (.70–.90), moderate (.50–.70), low (.30–.50), and no correlation (.00–.30). Results: The average TSK-11 score was 18.2 (5.3), average ACLR peak quadriceps torque was 1.9 (0.50) N·m/kg, average contralateral peak quadriceps torque was 2.3 (0.48) N·m/ kg, and average limb symmetry index was 85.3% (12.6%). There was no statistically significant correlation between the TSK-11 and peak quadriceps torque on the ACLR limb (r = .12, P = .46), the TSK-11 and contralateral limb (r = .29, P = .07), or the TSK-11 and limb symmetry index (r = –.18, P = .27). Conclusions: There was no association between kinesiophobia and peak isokinetic quadriceps strength in individuals at least 1 year post-ACLR. Both factors, independently, have been shown to influence risk of secondary injury in patients after ACLR.