HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rack, P M Articles by Ross, H F Search for Related Content PubMed PubMed Citation Articles by Rack, P M Articles by Ross, H F

Human flexor pollicis longus tendons obtained at autopsy were subjected to repeated sinusoidal stretching movements. The associated force changes were almost in phase with the movement (force led position by less than 4 degrees), and alterations in the frequency of movement between 2 and 16 Hz had little effect on them. Examination of the thumbs of formalin-fixed cadavers demonstrated that the tendon exerts its force 7.4-8.0 mm in front of the axis of movement of the interphalangeal joint. From a knowledge of the tendon properties and the joint anatomy, one can calculate the changes in tendon length that would accompany any force change at the joint. Equipped with this information one can re-examine the responses to sinusoidal movements of the thumb interphalangeal joints of normal subjects. When the subject exerts a steady flexing force in which stretch reflexes play no important part, measurements of joint stiffness indicate that only a portion of the imposed movement reaches the muscle fibres. The extension of those (visco-elastic) muscle fibres lags behind the extension of the (elastic) tendon. Stretch reflexes contribute to the mechanical resistance of muscle fibres to low frequency (3-5 Hz) displacements, but in the presence of a compliant tendon the length of the muscle fibres does not determine the angle of the joint in any positive way. It is suggested that the compliant tendons of many thumb and finger muscles simplify the neuromuscular control of forces during gripping and handling movements.

This article has been cited by other articles:

				N. J. Cronin, J. Peltonen, M. Ishikawa, P. V. Komi, J. Avela, T. Sinkjaer, and M. Voigt Effects of contraction intensity on muscle fascicle and stretch reflex behavior in the human triceps surae J Appl Physiol, July 1, 2008; 105(1): 226 - 232. [Abstract] [Full Text] [PDF]

				W. S. Yu, S. L. Kilbreath, R. C. Fitzpatrick, and S. C. Gandevia Thumb and finger forces produced by motor units in the long flexor of the human thumb J. Physiol., September 15, 2007; 583(3): 1145 - 1154. [Abstract] [Full Text] [PDF]

				J. Bojsen-Moller, P. Hansen, P. Aagaard, U. Svantesson, M. Kjaer, and S. P. Magnusson Differential displacement of the human soleus and medial gastrocnemius aponeuroses during isometric plantar flexor contractions in vivo J Appl Physiol, November 1, 2004; 97(5): 1908 - 1914. [Abstract] [Full Text] [PDF]

				D. C. Lin and W. Z. Rymer Damping Actions of the Neuromuscular System With Inertial Loads: Human Flexor Pollicis Longus Muscle J Neurophysiol, March 1, 2001; 85(3): 1059 - 1066. [Abstract] [Full Text] [PDF]

				M. De Zee, F. Bojsen-Moller, and M. Voigt Dynamic viscoelastic behavior of lower extremity tendons during simulated running J Appl Physiol, October 1, 2000; 89(4): 1352 - 1359. [Abstract] [Full Text] [PDF]

				M. Ito, Y. Kawakami, Y. Ichinose, S. Fukashiro, and T. Fukunaga Nonisometric behavior of fascicles during isometric contractions of a human muscle J Appl Physiol, October 1, 1998; 85(4): 1230 - 1235. [Abstract] [Full Text] [PDF]