title: Effect of cooling on thixotropic position-sense error in human biceps muscle.
abstract: Muscle temperature affects muscle thixotropy. However, it is unclear whether changes in muscle temperature affect thixotropic position-sense errors. We studied the effect of cooling on thixotropic position-sense errors induced by short-length muscle contraction (hold-short conditioning) in the biceps of 12 healthy men. After hold-short conditioning of the right biceps muscle in a cooled (5.0 degrees C) or control (36.5 degrees C) environment, subjects perceived greater extension of the conditioned forearm at 5.0 degrees C. The angle differences between the two forearms following hold-short conditioning of the right biceps muscle in normal or cooled conditions were significantly different (-3.335 +/- 1.680 degrees at 36.5 degrees C vs. -5.317 +/- 1.096 degrees at 5.0 degrees C; P=0.043). Induction of a tonic vibration reflex in the biceps muscle elicited involuntary forearm elevation, and the angular velocities of the elevation differed significantly between arms conditioned in normal and cooled environments (1.583 +/- 0.326 degrees /s at 36.5 degrees C vs. 3.100 +/- 0.555 degrees /s at 5.0 degrees C, P=0.0039). Thus, a cooled environment impairs a muscle's ability to provide positional information, potentially leading to poor muscle performance.
authors: Department of Physiology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors: Chikara
authors: C
authors: Sekihara
authors: Masahiko
authors: M
authors: Izumizaki
authors: Tomohiro
authors: T
authors: Yasuda
authors: Takayuki
authors: T
authors: Nakajima
authors: Takashi
authors: T
authors: Atsumi
authors: Ikuo
authors: I
authors: Homma
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D003080:Cold Temperature; D004548:Elasticity; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*