Neuromechanical control of the forearm muscles during gripping with sudden flexion and extension wrist perturbations.
The purpose of this study was to investigate how gripping modulates forearm muscle co-contraction prior to and during sudden wrist perturbations. Ten males performed a sub-maximal gripping task (no grip, 5% and 10% of maximum) while a perturbation forced wrist flexion or extension. Wrist joint angles and activity from 11 muscles were used to determine forearm co-contraction and muscle contributions to wrist joint stiffness. Co-contraction increased in all pairs as grip force increased (from no grip to 10% grip), corresponding to a 36% increase in overall wrist joint stiffness. Inclusion of individual muscle contributions to wrist joint stiffness enhanced the understanding of forearm co-contraction. The extensor carpi radialis longus (ECRL) and brevis had the largest stiffness contributions (34.5 ± 1.3% and 20.5 ± 2.3%, respectively), yet muscle pairs including ECRL produced the lowest co-contraction. The muscles contributing most to wrist stiffness were consistent across conditions (ECRL for extensors; Flexor Digitorum Superficialis for flexors), suggesting enhanced contributions rather than muscular redistribution. This work provides investigation of the neuromuscular response to wrist perturbations and gripping demands by considering both co-contraction and muscle contributions to joint stiffness. Individual muscle stiffness contributions can be used to enhance the understanding of forearm muscle control during complex tasks.
a Faculty of Health Sciences, University of Ontario Institute of Technology , 2000 Simcoe Street North, Oshawa , ON , Canada L1H 7K4.
Michael W R
MW
Holmes
Jimmy
J
Tat
Peter J
PJ
Keir
D000886:Anthropometry; D001696:Biomechanical Phenomena; D005542:Forearm / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D009424:Nervous System Physiological Phenomena; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D013997:Time Factors; D014953:Wrist / Q000502:physiology*; D014955:Wrist Joint / Q000502:physiology; D055815:Young Adult
biomechanical modeling; co-contraction; forearm; gripping; wrist