A comparison of two Hill-type skeletal muscle models on the construction of medial gastrocnemius length-tension curves in humans in vivo

作者：Hoffman B W; Lichtwark G A; Carroll T J; Cresswell A G^*

来源：Journal of Applied Physiology, 2012, 113(1): 90-96.

DOI：10.1152/japplphysiol.00070.2012

• force-length relationship
• ultrasonography
• muscle fascicle
• torque-angle relationship

Hoffman BW, Lichtwark GA, Carroll TJ, Cresswell AG. A comparison of two Hill-type skeletal muscle models on the construction of medial gastrocnemius length-tension curves in humans in vivo. J Appl Physiol 113: 90-96, 2012. First published May 10, 2012; doi:10.1152/japplphysiol.00070.2012.-Human length-tension curves are traditionally constructed using a model that assumes passive tension does not change during contraction (model A) even though the animal literature suggests that passive tension can decrease (model B). The study's aims were threefold: 1) measure differences in human medial gastrocnemius length-tension curves using model A vs. model B, 2) test the reliability of ultrasound constructed length-tension curves, and 3) test the robustness of fascicle length-generated length-tension curves to variations between the angle and fascicle length relationship. An isokinetic dynamometer manipulated and measured ankle angle while ultrasound was used to measure medial gastrocnemius fascicle length. Supramaximal tibial nerve stimulation was used to evoke resting muscle twitches. Length-tension curves were constructed using model A {angle-torque [A-T-(A)], length-torque [L-T-(A)]} or model B {length-torque [L-T-(B)]} in three conditions: baseline, heel-lift (where the muscle was shortened at each angle), and baseline repeated 2 h later (+2 h). Length-tension curves constructed from model B differed from those produced via model A, indicated by a significant increase in maximum torque (approximate to 23%) when using L-T-(B) vs. L-T(A). No parameter measured was different between baseline and +2 h for any method, indicating good reliability when using ultrasound. Length-tension curves were unaffected by the heel-lift condition when using L-T-(A) or L-T-(B) but were affected when using A-T-(A). Since the muscle model used significantly alters human length-tension curves, and given animal data indicate model B to be more accurate when passive tension is present, we recommend that model B should be used when constructing medial gastrocnemius length-tension curves in humans in vivo.

• 出版日期2012-7