Purpose: We combined a full-body musculoskeletal model with dynamic optimization theory to predict the biomechanics of maximum-speed sprinting and evaluate the effects of changes in muscle-tendon properties on sprint performance.
Methods: The body was modeled as a three-dimensional skeleton actuated by 86 muscle-tendon units. A simulation of jogging was used as an initial guess to generate a predictive dynamic optimization solution for maximum-speed sprinting. Nominal values of lower-limb muscle strength, muscle fascicle length, muscle intrinsic maximum shortening velocity (fiber-type composition), and tendon compliance were then altered incrementally to study the relative influence of each property on sprint performance.
Results: Model-predicted patterns of full-body motion, ground forces, and muscle activations were in general agreement with experimental data recorded for maximum-effort sprinting. Maximum sprinting speed was 1.3 times more sensitive to a change in muscle strength compared with the same change in muscle fascicle length, 2.0 times more sensitive to a change in muscle fascicle length compared with the same change in muscle intrinsic maximum shortening velocity, and 9.1 times more sensitive to a change in muscle intrinsic maximum shortening velocity compared with the same change in tendon compliance. A 10% increase in muscle strength increased maximum sprinting speed by 5.9%, whereas increasing muscle fascicle length, muscle intrinsic maximum shortening velocity, and tendon compliance by 10% increased maximum sprinting speed by 4.7%, 2.4%, and 0.3%, respectively.
Conclusions: Sprint performance was most sensitive to changes in muscle strength and least affected by changes in tendon compliance. Sprint performance was also more heavily influenced by changes in muscle fascicle length than muscle intrinsic maximum shortening velocity. These results could inform training methods aimed at optimizing performance in elite sprinters.
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http://dx.doi.org/10.1249/MSS.0000000000002978 | DOI Listing |
Quant Imaging Med Surg
January 2025
Department of Ultrasonic Diagnosis, The First Hospital of China Medical University, Shenyang, China.
Background: Patients with essential hypertension have a high risk of muscle mass and strength decline. Ultrasound is a promising method for assessing sarcopenia. This study aimed to analyze the correlation between ultrasound and shear-wave elastography (SWE) features, and muscle mass, muscle strength, and physical performance, and to assess the clinical applicability of ultrasound in the diagnosis of sarcopenia in patients with essential hypertension.
View Article and Find Full Text PDFJ Biomech
January 2025
School of Human Movement and Nutrition Sciences, University of Queensland, St Lucia Street, 4072 Brisbane, QLD, Australia; Faculty of Health. School of Exercise & Nutrition Sciences, Queensland University of Technology, 2 George St, Brisbane City, QLD 4000, Australia. Electronic address:
This study used musculoskeletal modelling to explore the relationship between cycling conditions (power output and cadence) and muscle activation and metabolic power. We hypothesized that the cadence that minimized the simulated average active muscle volume would be higher than the cadence that minimized the simulated metabolic power. We validated the simulation by comparing the predicted muscle activation and fascicle velocities with experimental electromyography and ultrasound images.
View Article and Find Full Text PDFPhysiol Rep
January 2025
Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
Both resistance training (RT) and long-duration, high-intensity stretching induce muscular adaptations; however, it is unknown whether the modalities are complementary or redundant, particularly in well-trained individuals. A case-study was conducted on a competitive bodybuilder implementing long-duration, high-intensity stretching of the plantar flexors (60 min 6x/week for 12 weeks) in conjunction with their habitual RT. Ultrasound muscle architecture (muscle thickness [MT], fascicle length [FL], and pennation angle [PA]) measurements were collected at multiple sites at four weekly baseline sessions, six (mid) and 12 (post1) weeks following the commencement of the intervention, and a week after the intervention (post2) while isometric strength and range of motion (RoM) were obtained once at baseline, mid, post1, and post2.
View Article and Find Full Text PDFInvestigating muscle architecture in static and dynamic conditions is essential to understand muscle function and muscle adaptations. Muscle architecture analysis, primarily through extended field-of-view ultrasound imaging, offers high reliability at rest but faces limitations during dynamic conditions. Traditional methods often involve "best fitting" straight lines to track muscle fascicles, leading to possible errors, especially with longer fascicles or those with nonlinear paths.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Sport Sciences, Waseda University, Saitama, Japan.
Walking patterns can differ between children and adults, both kinematically and kinetically. However, the detailed nature of the ankle pattern has not been clarified. We investigated musculature, biomechanics, and muscle activation strategies and their relevance to walking performance in preschool (PS) and school children (SC), with adults (AD) as reference.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!