title: The role of biceps brachii and brachioradialis for the control of elbow flexion and extension movements.
abstract: How do synergistic muscles interact, when their contraction aims at stabilizing and fine-tuning a movement, which is induced by the antagonistic muscle? The aim of the study was to analyze the interaction of biceps and brachioradialis during fine-tuning control tasks in comparison to load bearing ones. The surface electromyogram of biceps, brachioradialis and triceps were examined in 15 healthy subjects in dynamic flexion and extension movements with different combinations of contraction levels, joint angles and angular velocities. The measurements were conducted in two configurations, where the torque due to an external load opposes the rotational direction of the elbow flexion (load bearing tasks) or the elbow extension (fine-tuning tasks). Whereas during load bearing control tasks, similar muscular activation of biceps and brachioradialis was observed for all joint angles, angular velocities and external loads, during fine-tuning control tasks a significant difference of the muscular activation of both flexors was observed for 1kg, F(3.639,47.305)=2.864, p=0.037, and 5kg of external load, F(1.570,21.976)=6.834, p=0.008. The results confirm the synergistic muscular activation of both flexors during load bearing tasks, but suggest different control strategies for both flexors when they comprise a fine-tuning control task.
authors.affiliation: Department of Rehabilitation & Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University, Aachen, Germany. Electronic address: vonwerder@ame.rwth-aachen.de.
authors.forename: Sylvie Charlotte Frieda Anneliese
authors.initials: SC
authors.lastname: von Werder
authors.affiliation: Department of Rehabilitation & Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University, Aachen, Germany.
authors.forename: Catherine
authors.initials: C
authors.lastname: Disselhorst-Klug
mesh_terms: D000328:Adult; D004550:Elbow / Q000502:physiology; D004551:Elbow Joint / Q000502:physiology*; D004576:Electromyography / Q000379:methods; D005260:Female; D005542:Forearm / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D019415:Torque; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
keywords: Biceps; Brachioradialis; Categorization; Control; Muscular activation