title: Analysis of "Teno-uchi" maneuver in releasing Japanese-style bows based on muscle activities and forces acting on the bow.
abstract: Since a Japanese-style bow has a very complicated shape and structure, an archer has to apply the "Teno-uchi" maneuver including horizontally twisting torque, or "Nejiri", and sagittally down-pushing torque, or "Uwa-oshi", to the restoring bow in order to hit the target. The purpose of this study was to investigate the biomechanical relationship between the muscular activities of the left forearm and the operation of "Teno-uchi" maneuver. Surface EMG of left forearm muscles and the two kinds of torque acting on the bow around the time of release were recorded in 10 experienced subjects during arrow shooting. The "Biku", an involuntary resignation from release happening in the shooting, was also examined. Close analyses of the results revealed that activation of the extensor carpi ulnaris and extensor digitorum muscles together with inhibition of the flexor carpi ulnaris muscle brought about "Nejiri", while activation of the extensor carpi ulnaris as well as flexor carpi ulnaris muscles and inhibition of the extensor carpi redialis longus and extensor digitorum muscles gave rise to "Uwa-oshi", thus causing activities of trade-off nature in the extensor digitorum and flexor carpi ulnaris muscles for the "Nejiri" and "Uwa-oshi. The trade-off activities were presumably actualized through time-sharing coordination between the muscles.
authors.affiliation: Department of KANSEI Engineering, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan. hosoya@shinshu-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hosoya
authors.forename: Keigo Ohyama
authors.initials: KO
authors.lastname: Byun
authors.forename: Morihiko
authors.initials: M
authors.lastname: Okada
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D006804:Ergonomics; D005542:Forearm / Q000502:physiology*; D006801:Humans; D007564:Japan; D008297:Male; D016139:Martial Arts / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D011597:Psychomotor Performance; D019415:Torque; D034941:Upper Extremity / Q000502:physiology*