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Arumugam A1, Svanberg F1, Rutgersson J1, Häger CK1
1Umeå University, Department of Community Medicine and Rehabilitation – Physiotherapy Section, Umeå, Sweden
Background: We designed a novel one-leg double-hop test emulating a cutting maneuver that might challenge anterior cruciate ligament (ACL) integrity. A good neuromuscular control of the thigh muscles is crucial to maintain dynamic knee stability during the task. Therefore, there is a need to assess thigh muscles cocontraction strategies in order to understand their role in ACL injury risk and rehabilitation.
Purpose: To examine electromyographic patterns of the hamstrings and quadriceps during the one-leg double-hop test in individuals with ACL reconstruction (ACLR), athletes and controls. Specifically, the study determined whether cocontraction of these muscle groups differed during the pre-landing and (decelerating) landing phases of the land-and-cut maneuver in the three groups.
Methods: In this cross-sectional study, 25 individuals with ACLR, 22 athletes and 22 controls performed the novel test comprising of a forward hop followed by a diagonal hop (45°) performed in medial (UMDH) or lateral direction (ULDH) without pre-planning the diagonal hopping direction. Electromyography of the medial and lateral hamstrings and quadriceps were recorded for the operated limb of individuals with ACLR and the nondominant limb of athletes and controls. With normalized root-mean-square electromyographic data, hamstring-to-quadriceps ratio, lateral and medial quadriceps-to-hamstring cocontraction indices (CCIs), and medial-to-lateral quadriceps-to-hamstring cocontraction ratio (CCR = medial quadriceps-to-hamstring CCI/lateral quadriceps-to-hamstring CCI) were calculated for three phases of the land-and-cut maneuver (100 ms pre-landing, 10 % stance, and 10-50% stance; stance: initial-foot-contact to toe-off) of UMDH and ULDH. Multiple 3 (groups) x 3 (phases) mixed analysis of variances were used (p 0.050).
Results: Significant interactions between groups and phases were observed for both medial and lateral quadriceps-to-hamstring CCIs for UMDH (p≤0.042). Significant main effects of phases (p 0.001), regardless of group, were observed for hamstring-to-quadriceps ratio (UMDH and ULDH), medial and lateral quadriceps-to-hamstring CCIs (ULDH) and medial-to-lateral quadriceps-to-hamstring CCR (UMDH). The hamstring-to-quadriceps ratios (UMDH/ULDH) revealed an increased activity of the quadriceps than the hamstrings during the initial 10% and 10-50% stance but an opposite trend was noticed 100 ms pre-landing. The ACLR group demonstrated lower medial/lateral quadriceps-to-hamstring CCIs than athletes and controls during 100 ms pre-landing of UMDH. All groups showed a relatively low imbalance in the medial-to-lateral quadriceps-to-hamstring CCRs for 100 ms pre-landing phase compared to 10% and 10-50% stance for UMDH. This indicates higher cocontraction of the medial thigh muscles than the lateral group causing knee adduction during the initial 10% and 10-50% stance of UMDH.
Conclusion(s): All groups presented a high hamstring-to-quadriceps ratio in the pre-landing phase and a low hamstring-to-quadriceps ratio during the 10% and 10-50% stance of UMDH/ULDH. Moreover, in all groups, there was a predominant cocontraction of the medial thigh muscles compared to the lateral group (cf. medial-to-lateral quadriceps-to-hamstring CCRs), causing knee adduction during the initial 10% and 10-50% stance of UMDH.
Implications: The test was feasible with thigh muscle cocontraction strategies augmenting knee adduction during the deceleration phase of the land-and-cut maneuver. This reflects a strategy to mitigate ACL injury risk in all three groups. The novel double-hop test might be useful to evaluate knee function in ACLR rehabilitation.
Keywords: Land-and-cut maneuver, hamstring/quadriceps ratio, muscle cocontraction
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 examine electromyographic patterns of the hamstrings and quadriceps during the one-leg double-hop test in individuals with ACL reconstruction (ACLR), athletes and controls. Specifically, the study determined whether cocontraction of these muscle groups differed during the pre-landing and (decelerating) landing phases of the land-and-cut maneuver in the three groups.
Methods: In this cross-sectional study, 25 individuals with ACLR, 22 athletes and 22 controls performed the novel test comprising of a forward hop followed by a diagonal hop (45°) performed in medial (UMDH) or lateral direction (ULDH) without pre-planning the diagonal hopping direction. Electromyography of the medial and lateral hamstrings and quadriceps were recorded for the operated limb of individuals with ACLR and the nondominant limb of athletes and controls. With normalized root-mean-square electromyographic data, hamstring-to-quadriceps ratio, lateral and medial quadriceps-to-hamstring cocontraction indices (CCIs), and medial-to-lateral quadriceps-to-hamstring cocontraction ratio (CCR = medial quadriceps-to-hamstring CCI/lateral quadriceps-to-hamstring CCI) were calculated for three phases of the land-and-cut maneuver (100 ms pre-landing, 10 % stance, and 10-50% stance; stance: initial-foot-contact to toe-off) of UMDH and ULDH. Multiple 3 (groups) x 3 (phases) mixed analysis of variances were used (p 0.050).
Results: Significant interactions between groups and phases were observed for both medial and lateral quadriceps-to-hamstring CCIs for UMDH (p≤0.042). Significant main effects of phases (p 0.001), regardless of group, were observed for hamstring-to-quadriceps ratio (UMDH and ULDH), medial and lateral quadriceps-to-hamstring CCIs (ULDH) and medial-to-lateral quadriceps-to-hamstring CCR (UMDH). The hamstring-to-quadriceps ratios (UMDH/ULDH) revealed an increased activity of the quadriceps than the hamstrings during the initial 10% and 10-50% stance but an opposite trend was noticed 100 ms pre-landing. The ACLR group demonstrated lower medial/lateral quadriceps-to-hamstring CCIs than athletes and controls during 100 ms pre-landing of UMDH. All groups showed a relatively low imbalance in the medial-to-lateral quadriceps-to-hamstring CCRs for 100 ms pre-landing phase compared to 10% and 10-50% stance for UMDH. This indicates higher cocontraction of the medial thigh muscles than the lateral group causing knee adduction during the initial 10% and 10-50% stance of UMDH.
Conclusion(s): All groups presented a high hamstring-to-quadriceps ratio in the pre-landing phase and a low hamstring-to-quadriceps ratio during the 10% and 10-50% stance of UMDH/ULDH. Moreover, in all groups, there was a predominant cocontraction of the medial thigh muscles compared to the lateral group (cf. medial-to-lateral quadriceps-to-hamstring CCRs), causing knee adduction during the initial 10% and 10-50% stance of UMDH.
Implications: The test was feasible with thigh muscle cocontraction strategies augmenting knee adduction during the deceleration phase of the land-and-cut maneuver. This reflects a strategy to mitigate ACL injury risk in all three groups. The novel double-hop test might be useful to evaluate knee function in ACLR rehabilitation.
Keywords: Land-and-cut maneuver, hamstring/quadriceps ratio, muscle cocontraction
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, Sweden
Ethics committee: Regional Ethical Review board in Umeå, Sweden
Ethics number: 2015/67-31
All authors, affiliations and abstracts have been published as submitted.
