Facilitation of triceps brachii muscle contraction by tendon vibration after chronic cervical spinal cord injury

• Published in: Journal of applied physiology (1985) 2003-06, Vol.94 (6), p.2358-2367
• Main Authors: Ribot-Ciscar, Edith, Butler, Jane E, Thomas, Christine K
• Format: Article
• Language: English
• Subjects: Adult; Arm; Biological and medical sciences; Cervical Vertebrae; Chronic Disease; Elbow; Female; Fundamental and applied biological sciences. Psychology; Humans; Isometric Contraction; Life Sciences; Male; Middle Aged; Muscle, Skeletal - physiopathology; Muscular system; Neurons and Cognition; Paralysis; Reflex - physiology; Reflexes; Spinal cord injuries; Spinal Cord Injuries - physiopathology; Striated muscle. Tendons; Tendons; Tendons - physiopathology; Vertebrates: osteoarticular system, musculoskeletal system; Vibration
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00894.2002

1  Laboratoire de Neurobiologie Humaine, Unité Mixte de Recherche Centre National de la Recherche Scientifique 6149 "Neurobiologie Intégrative et Adaptative," 13397 Marseille, France; 2  Prince of Wales Medical Research Institute, Randwick, New South Wales 2031, Australia; and 3  The Miami Project to Cure Paralysis, University of Miami School of Medicine, Miami, Florida 33136 One way to improve the weak triceps brachii voluntary forces of people with chronic cervical spinal cord injury may be to excite the paralyzed or submaximally activated fraction of muscle. Here we examined whether elbow extensor force was enhanced by vibration (80 Hz) of the triceps or biceps brachii tendons at rest and during maximum isometric voluntary contractions (MVCs) of the elbow extensors performed by spinal cord-injured subjects. The mean ± SE elbow extensor MVC force was 22 ± 17.5 N (range: 0-23% control force, n  = 11 muscles). Supramaximal radial nerve stimuli delivered during elbow extensor MVCs evoked force in six muscles that could be stimulated selectively, suggesting potential for force improvement. Biceps vibration at rest always evoked a tonic vibration reflex in biceps, but extension force did not improve with biceps vibration during triceps MVCs. Triceps vibration induced a tonic vibration reflex at rest in one-half of the triceps muscles tested. Elbow extensor MVC force (when >1% of control force) was enhanced by vibration of the triceps tendon in one-half of the muscles. Thus triceps, but not biceps, brachii tendon vibration increases the contraction strength of some partially paralyzed triceps brachii muscles. tonic vibration reflex; antagonist vibratory response; muscle weakness; muscle paralysis; maximum voluntary contraction