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Arumugam A1, Jonsson P2, Antti H2, Häger CK1
1Umeå University, Department of Community Medicine and Rehabilitation – Physiotherapy Section, Umeå, Sweden, 2Umeå University, Department of Chemistry, Umeå, Sweden
Background: A change-of-direction (cutting) maneuver might challenge knee stability or anterior cruciate ligament (ACL) integrity during an unanticipated condition compared to its pre-planned counter-part. Therefore, we proposed a novel one-leg double-hop test including a forward hop followed by a 45°-diagonal hop in medial (UMDH) or lateral direction (ULDH) without pre-planning the hopping direction.
Purpose: To evaluate the effects of hop direction (UMDH vs. ULDH) and leg (operated vs. uninjured; non-dominant vs. dominant) between individuals with ACL reconstruction (ACLR), athletes and controls using multivariate analysis of trunk and lower limb biomechanical variables analyzed during the test.
Methods: Twenty nine individuals with a unilateral ACLR (33.7±31.6 months post-ACLR), 22 healthy elite athletes and 24 healthy controls performed five double hops for each leg per direction. An 8-camera 3-dimensional motion analysis system (240 Hz) and 2 force plates (1680 Hz) were used. Participants performed the diagonal hops based on a visual cue, presented ≈300 ms before the land-and-cut maneuver, randomly indicating the hop direction. Biomechanical variables of the trunk and lower limbs were calculated with Visual3DTM during one or more phases of the land-and-cut maneuver: initial-foot-contact, deceleration (initial-foot-contact to peak knee flexion) and acceleration (peak knee flexion to toe-off). We analyzed 196 variables (peak angles and/or moments of the hip, knee, ankle and trunk, timing of events, angle-of-cut, etc.). Regression analysis was used to calculate coefficients: “constant”, “direction”, “leg”, and “interaction” (between leg and direction), for each person and variable. The four sets of coefficients, independently describing variation related to each factor, were analyzed by multivariate statistics using orthogonal projections to latent structures discriminant analysis (OPLS-DA) in MATLAB® to model systematic differences between groups. No significant differences were found between athletes and controls and therefore their data were grouped together to compare with ACLR group.
Results: Significant OPLS-DA models, differentiating ACLR group from the others, were found for constant (p=0.002), direction (p 0.001) and leg (p=0.036) but not for interaction (p>0.050). The OPLS-DA model based on coefficients for the constant revealed that knee sagittal angles during the initial-foot-contact, deceleration and acceleration phases were significantly higher for the ACLR group compared to controls/athletes (false discovery rate [FDR] 0.050). The OPLS-DA model based on coefficients for the direction revealed that differences between directions in patients were lower for hip external rotation angle in the acceleration phase and higher for the timing of peak external knee adduction moment during the land-and-cut maneuver compared to controls/athletes (FDR 0.050). The OPLS-DA model based on coefficients for the leg did not reveal any significant variable with FDR 0.050.
Conclusion(s): Patients with ACLR showed higher knee sagittal angles during the land-and-cut maneuver compared to controls/athletes regardless of leg and direction. Further, the timing of peak knee adduction moment was more variable between directions for the ACLR group, which might be a repercussion of ACL injury, compared to the others.
Implications: The novel test was feasible and seem useful to evaluate movement asymmetries during one-leg land-and-cut maneuvers in individuals with ACLR during rehabilitation. Further, multivariate analyses may disentangle the effects of hop designs on multi-joint movement patterns.
Keywords: Change-of-direction maneuver, hop test, motion analysis
Funding acknowledgements: Swedish Scientific Research Council, Västerbotten-County Council, Swedish National Centre for Research in Sports, and Umeå University School of Sport Science.
Purpose: To evaluate the effects of hop direction (UMDH vs. ULDH) and leg (operated vs. uninjured; non-dominant vs. dominant) between individuals with ACL reconstruction (ACLR), athletes and controls using multivariate analysis of trunk and lower limb biomechanical variables analyzed during the test.
Methods: Twenty nine individuals with a unilateral ACLR (33.7±31.6 months post-ACLR), 22 healthy elite athletes and 24 healthy controls performed five double hops for each leg per direction. An 8-camera 3-dimensional motion analysis system (240 Hz) and 2 force plates (1680 Hz) were used. Participants performed the diagonal hops based on a visual cue, presented ≈300 ms before the land-and-cut maneuver, randomly indicating the hop direction. Biomechanical variables of the trunk and lower limbs were calculated with Visual3DTM during one or more phases of the land-and-cut maneuver: initial-foot-contact, deceleration (initial-foot-contact to peak knee flexion) and acceleration (peak knee flexion to toe-off). We analyzed 196 variables (peak angles and/or moments of the hip, knee, ankle and trunk, timing of events, angle-of-cut, etc.). Regression analysis was used to calculate coefficients: “constant”, “direction”, “leg”, and “interaction” (between leg and direction), for each person and variable. The four sets of coefficients, independently describing variation related to each factor, were analyzed by multivariate statistics using orthogonal projections to latent structures discriminant analysis (OPLS-DA) in MATLAB® to model systematic differences between groups. No significant differences were found between athletes and controls and therefore their data were grouped together to compare with ACLR group.
Results: Significant OPLS-DA models, differentiating ACLR group from the others, were found for constant (p=0.002), direction (p 0.001) and leg (p=0.036) but not for interaction (p>0.050). The OPLS-DA model based on coefficients for the constant revealed that knee sagittal angles during the initial-foot-contact, deceleration and acceleration phases were significantly higher for the ACLR group compared to controls/athletes (false discovery rate [FDR] 0.050). The OPLS-DA model based on coefficients for the direction revealed that differences between directions in patients were lower for hip external rotation angle in the acceleration phase and higher for the timing of peak external knee adduction moment during the land-and-cut maneuver compared to controls/athletes (FDR 0.050). The OPLS-DA model based on coefficients for the leg did not reveal any significant variable with FDR 0.050.
Conclusion(s): Patients with ACLR showed higher knee sagittal angles during the land-and-cut maneuver compared to controls/athletes regardless of leg and direction. Further, the timing of peak knee adduction moment was more variable between directions for the ACLR group, which might be a repercussion of ACL injury, compared to the others.
Implications: The novel test was feasible and seem useful to evaluate movement asymmetries during one-leg land-and-cut maneuvers in individuals with ACLR during rehabilitation. Further, multivariate analyses may disentangle the effects of hop designs on multi-joint movement patterns.
Keywords: Change-of-direction maneuver, hop test, motion analysis
Funding acknowledgements: Swedish Scientific Research Council, Västerbotten-County Council, Swedish National Centre for Research in Sports, and Umeå University School of Sport Science.
Topic: Musculoskeletal: lower limb; Musculoskeletal: lower limb; Sport & sports injuries
Ethics approval required: Yes
Institution: Umeå University
Ethics committee: The Regional Ethical Review board in Umeå
Ethics number: 2015/67-31
All authors, affiliations and abstracts have been published as submitted.
