Architectural model for muscle growth during maturation

Abstract

Muscle architecture, which includes parameters like fascicle length, pennation angle, and physiological cross-sectional area, strongly influences skeletal muscles' mechanical properties. During maturation, the muscle architecture has to adapt to a growing organism. This study aimed to develop an architectural model capable of predicting the complete 3D fascicle architecture for primarily unipennate muscles of an arbitrary age, based on fascicle data for an initial age. For model development, we collected novel data on 3D muscle architecture of the rabbit (Oryctolagus cuniculus) M. plantaris of eight animals ranging in age from 29 to 106 days. Experimental results show that plantaris muscle belly length increases by 73%, whereas mean fascicle length and mean pennation angle increases by 39 and 14%, respectively. Those changes were incorporated into the model. In addition to the data collected for M. plantaris the predictions of the model were compared to existing literature data of rabbit M. soleus and M. gastrocnemius medialis. With an error of −1.0 ± 8.6% for relative differences in aponeurosis length, aponeurosis width, muscle height, and muscle mass, the model delivered good results matching interindividual differences. For future studies, the model could be utilized to generate realistic architectural data sets for simulation studies.

Stimuli for Adaptations in Muscle Length and the Length Range of Active Force Exertion—A Narrative Review

“…In rat parallel fibered muscles, growth is only determined by longitudinal muscle fiber growth (Willems and Huijing, 1992), while in pennate muscles of rats and ducks, longitudinal muscle growth also occurs by radial growth of muscle fibers (Swatland, 1980;Woittiez et al, 1986;Papenkort et al, 2020). During development, muscle PCSA increases (Woittiez et al, 1986(Woittiez et al, , 1989de Koning et al, 1987;Papenkort et al, 2020Papenkort et al, , 2021 by an increase in fCSA (Swatland, 1980;Alnaqeeb and Goldspink, 1987;Willems and Huijing, 1992). Although some studies (e.g., Enesco and Puddy, 1964;Ross et al, 1987) have reported hyperplasia during postnatal development in rat muscles, more have shown that hyperplasia does not occur in muscles from rodents (Goldspink, 1972;Timson and Dudenhoeffer, 1990;White et al, 2010).…”

“…In an almost completely parallel fibered muscle (i.e., semimembranosus lateralis of the rat), the fiber PA has been found to increase during development (Willems and Huijing, 1992). In pennate muscles of growing rats and rabbits (GM) and rabbits (soleus and plantaris muscles), it seems that the PA increases only slightly during growth (Heslinga and Huijing, 1990;Papenkort et al, 2020Papenkort et al, , 2021. Note that changes in PA over age may differ between muscle types (cf.…”

Histomorphological and functional contralateral symmetry in the gastrocnemius muscles of the laboratory rat

“…FCSA and SF depend on the accuracy of the cryostat cuts since these parameter's values could be altered with changes on the sample orientation in the cryostat and also due to the 3D muscle fibre architecture. The line of action between muscle insertion and its origin is different depending on the level where cuts were done due to differences in fibre length, pennation angle and curvature (Papenkort et al, 2020 ; Stark & Schilling, 2010 ; Wick et al, 2018 ). This intramuscular architecture entails different fibre morphometrical measurements along the proximal, equatorial or distal muscle level (Torrella et al, 2000 ).…”

“…Data from the right gastrocnemius are shown in white boxes and data from the left gastrocnemius in grey boxes. p-values resulting from statistical comparisons between right and left muscles after running paired t-Student tests are shown for each muscle zone on the graph fibre length, pennation angle and curvature(Papenkort et al, 2020;…”

Prediction of rotator cuff muscle fibre orientations using a population-averaged atlas generated with anatomical and diffusion-weighted magnetic resonance images

“…While the architecture of any particular muscle is broadly similar across individuals, muscle architecture can adapt to exercise (Alonso-Fernandez et al, 2018; Blazevich et al, 2003;Roig et al, 2008), ageing (Narici et al, 2003;Papenkort et al, 2021;Shur et al, 2021;Siebert et al, 2017) and disease (Bodine et al, 1982; Fahn-Lai et al, 2020; Kruse et al, 2018; J. E. Park et al, 2019). Quantitative measurement of muscle-and subject-speci c architecture is therefore useful for the study of muscle adaptation and muscle dysfunction.…”