Context: Current lower-extremity return to sport testing primarily considers the physical status of an athlete; however, sport participation requires continuous cognitive dual-task engagement. Therefore, the purpose was to develop and evaluate the reliability of a visual-cognitive reactive (VCR) triple hop test that simulates the typical sport demand of combined online visual-cognitive processing and neuromuscular control to improve return to sport testing after lower-extremity injury. Design: Test–retest reliability. Methods: Twenty-one healthy college students (11 females, 23.5 [3.7] y, 1.73 [0.12] m, 73.0 [16.8] kg, Tegner Activity Scale 5.5 [1.1] points) participated. Participants performed a single-leg triple hop with and without a VCR dual task. The VCR task incorporated the FitLight system to challenge peripheral response inhibition and central working memory. Maximum hop distance, reaction time, cognitive errors, and physical errors were measured. Two identical testing visits were separated by 12 to 17 days (14 [1] d). Results: Traditional triple hop (intraclass correlation coefficients: ICC(3,1) = .96 [.91–.99]; standard error of the measurement = 16.99 cm) and the VCR triple hop (intraclass correlation coefficients(3,1) = .92 [.82–.97]; standard error of the measurement = 24.10 cm) both demonstrated excellent reliability for the maximum hop distance, and moderate reliability for the VCR triple hop reaction time (intraclass correlation coefficients(3,1) = .62 [.09–.84]; standard error of the measurement = 0.09 s). On average, the VCR triple hop resulted in a hop distance deficit of 8.17% (36.4 [5.1] cm; P < .05, d = 0.55) relative to the traditional triple hop. Conclusions: Hop distance on the VCR triple hop had excellent test–retest reliability and induced a significant physical performance deficit when compared with the traditional triple hop assessment. The VCR triple hop reaction time also demonstrated moderate reliability.
Recovery from anterior cruciate ligament reconstruction (ACLR) induces bilateral functional and physiological adaptations. Neurophysiologic measures of motor control have focused on the involved knee joint, limiting understanding regarding the extent of bilateral neural adaptations. Therefore, the aim of this study was to investigate differences in neural activity during uninvolved-limb motor control after ACLR compared to healthy controls. Methods: Fifteen participants with left ACLR (8 female and 7 male, 21.53 ± 2.7 years, 173.22 ± 10.0 cm, 72.15 ± 16.1 kg, Tegner 7.40 ± 1.1, 43.33 ± 33.1 mo. post-surgery, 2 patellar tendon, and 13 hamstring) and 15 matched controls (8 female, 23.33 ± 2.7 years, 174.92 ± 9.7 cm, 72.14 ± 15.4 kg, Tegner 7.33 ± 1.0) participated. Neural activity was evaluated using functional magnetic resonance imaging on a 3T Siemens Magnetom scanner during four 30-s cycles of a right (uninvolved) knee flexion-extension task paced with a metronome (1.2 Hz) and was completed interspersed with 30 s of rest. A significance threshold of p < 0.05 was used for all analyses, cluster corrected for multiple comparisons, and z-thresholds of >3.1 (subject level), and >2.3 (group level). Results: The ACLR group had greater neural activity in one statistically significant cluster corresponding to the left middle frontal gyrus (MFG) (834 voxels, z = 3.81, p < 0.01 multiple comparisons corrected) compared to controls. Conclusions: These data indicate a potential contribution to uninvolved-knee neuromuscular deficits after injury and support the limitations of using the uninvolved side as a clinical reference. Uninvolved knee motor control after ACLR may require greater cognitive demand. Clinicians should be aware that the uninvolved limb might also demonstrate whole brain alterations limiting clinical inference from functional symmetry.
Clinical Scenario: Anterior cruciate ligament (ACL) injuries remain one of the most common and debilitating injuries that physically active individuals experience. Pain-related fear of movement and/or reinjury, or kinesiophobia, is the most frequently cited reason for not returning to sport after ACL reconstruction. Understanding how kinesiophobia may impact recovery of physical performance is essential to guide targeted rehabilitation. Clinical Question: Does kinesiophobia associate with physical performance in patients with a history of ACL reconstruction? Summary of Key Findings: Five cross-sectional studies investigating bivariate relationships between kinesiophobia and metrics of physical performance among individuals with a history of primary, unilateral ACL reconstruction were included. From a strength perspective, greater kinesiophobia associated with lesser isometric knee flexion torque (n = 1, negligible association) but did not associate with isokinetic or isometric knee extension torque (n = 2). In terms of functional movement, greater kinesiophobia associated with asymmetric single-leg step-down performance (n = 1, high association) and shorter single-leg hop distance (n = 1, negligible association). Biomechanically, greater kinesiophobia associated with worse drop jump landing, characterized by greater frontal plane motion and lesser sagittal plane motion at the hip and knee joints (n = 1, low to high association). Clinical Bottom Line: Very low-quality evidence suggests a muscle-specific association between kinesiophobia and strength. Low- to moderate-quality evidence suggests that greater kinesiophobia associates with worse functional movement and landing biomechanics. Strength of Recommendation: Considering the consistency and level of evidence among the included studies, we offer the following grades for each construct of physical performance evaluated: strength, D; functional movement, B; and biomechanics, B.