Int J Sports Med 2021; 42(06): 550-558
DOI: 10.1055/a-1292-4461
Orthopedics & Biomechanics

Impaired Regulation of Submaximal Force after ACL Reconstruction: Role of Muscle Spindles

David Rice
1  Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
2  Department of Anaesthesia and Perioperative Medicine, North Shore Hospital, Auckland, New Zealand
,
1  Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
,
Peter McNair
1  Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
› Author Affiliations

Abstract

Ongoing motor deficits are routinely present following anterior cruciate ligament (ACL) reconstruction, including the ability to regulate muscle force. While such deficits are known, it is unclear why this occurs. The goal of the current study was to investigate the potential influence of muscle spindle input on submaximal force regulation and muscle activity at the knee in people following ACL reconstruction. Fourteen participants (8 female) who were 6−24 months post-ACL reconstruction and 15 control participants (8 female) undertook submaximal force matching and force modulation tasks before and after 20 min of vibration applied to the patella tendon. Across all tasks, the ACL reconstruction participants were poorer at force matching (P=0.007). The effect of vibration was not significant in either group for the force matching tasks (P=0.06), although there was a reduction in maximum voluntary contraction post-vibration in the control group (P<0.001). The ACL reconstruction group also showed evidence of greater activation of the medial hamstring muscles in comparison to controls (P=0.04). Individuals who have undergone ACL reconstruction have a diminished ability to accurately match and regulate submaximal muscle force, but this does not appear to be related to impaired muscle spindle input. Neuromuscular retraining programs that involve force regulation tasks may be necessary to optimize rehabilitation after ACL reconstruction.



Publication History

Received: 21 April 2020

Accepted: 12 October 2020

Publication Date:
11 November 2020 (online)

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