A three‐dimensional muscle model: A quantified relation between form and function of skeletal muscles

Abstract

A three-dimensional muscle model with complex geometry is described and tested against experimental data. Using this model, several muscles were constructed. These muscles have equal optimum length but differ in architecture. The force exerted by the constructed muscles, in relation to their actual length and velocity of shortening, is discussed. Generally speaking, the constructed muscles with considerable pennation have great fiber angles, a great physiological cross section, a narrow active and steep passive length-force relation, and a low maximal velocity of shortening. The maximal power (force times velocity) delivered by the constructed muscles is shown to be almost independent of the architecture of the muscles. The steepness of the passive length-force relation is determined mainly by the shortest fibers within the group of constructed muscles, whereas maximal velocity of shortening and the width of the active length-force relation are determined mainly by the longest fibers. The validity of the three-dimensional muscle model with respect to some morphological and functional characteristics is tested. Length-force relations of constructed muscles are compared with the actual length-force relations of mm. gastrocnemii mediales and mm. semimembranosi of male Wistar rats. Moreover, actual fiber angle, fiber length, and muscle thickness of three mm. gastrocnemii mediales are compared with values found for constructed muscles. It is concluded that the three-dimensional muscle model closely approximates the actual muscle form and function.

Progressive surgical dissection for tendon transposition affects length‐force characteristics of rat flexor carpi ulnaris muscle

“…To this point, isometric muscular length-force characteristics have been studied using isolated preparations of: (1) single isolated muscle fiber [3], (2) isolated fascicles [27], or (3) isolated whole muscle in situ [26]. Therefore, the possible role of the surrounding connective tissue in force transmission has largely been neglected.…”

Role of intra-abdominal pressure in the unloading and stabilization of the human spine during static lifting tasks

“…It is important to emphasize that any changes in this maximum stress value would directly influence the forces considered in the abdominal muscles for different cases. The passive tension-length relationship was also assumed to be the same for all the muscles despite the fact that the specific architecture of each muscle could influence this relationship [74]. The passive tension-length curve used in the current study was adapted from recent experimental data [25], which is in the range of those reported by others [48,58,74].…”

“…The passive tension-length relationship was also assumed to be the same for all the muscles despite the fact that the specific architecture of each muscle could influence this relationship [74]. The passive tension-length curve used in the current study was adapted from recent experimental data [25], which is in the range of those reported by others [48,58,74]. It is important to emphasize that the passive force-length and stiffness relations considered for muscles in the current study have absolutely no bearing at all on the predicted spinal loads and muscle forces.…”

Architecture of the human jaw‐closing and jaw‐opening muscles

“…Because of the particular arrangement of the sarcomeres within the muscle, the functional capabilities of the whole muscle can be different from those of the sarcomeres. In pennated muscles, fiber length change is less than muscle length change (Muhl, 1982;Woittiez et al, 1984), and the difference in length change increases with pennation angle. Several muscle models have been developed to account for the effects of different muscle architectures and to describe the relationship between muscle length changes and sarcomere length changes and the consequences for the production of relative force and excursion range (Otten, 1988;Kaufman et al, 1989;Spoor et al, 1991).…”