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Physical and Physiological Reponses and Adaptations
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
Factors such as gross muscle architecture, angle of pennation, muscle insertion point, height, limb length, and moment arm may alter the mechanical advantage of the intact muscle lever system. For example, weightlifters possess a high ratio of body mass to height (BM h-1) compared to untrained subjects and other athletic groups. This BM h-1 is advantageous because it can provide an increased force production. This advantage is associated with the strong positive relationship between a muscle’s physiological cross-sectional area and maximum muscle force-generating capabilities (75). If two athletes of different heights and different limb lengths have the same muscle mass and volume, the shorter athlete will have the greatest muscle cross-section and therefore, greater force production.
Not just cousins
Published in Francesco E. Marino, Human Fatigue, 2019
Table 3.2 summarises some apparent key musculoskeletal differences between humans and chimpanzees that have been shown to account for some of the disparity in mobility, strength and locomotion. It can be seen from these data that chimpanzees have almost twice as much muscle mass in the forelimbs compared to humans. However, humans have significantly more muscle mass in their hind limbs. An important component of skeletal muscle mechanics is the bundle of muscle fibres known as fascicles. The length of the fascicle also determines the number of sarcomeres that are in series, and since sarcomeres contain the contractile elements of skeletal muscle, the number of sarcomeres plays an important role in muscle shortening. Although human hind limbs have a larger muscle mass and, therefore, a greater physiological cross-sectional area (PCSA), we have comparably shorter fascicle lengths compared with chimpanzees. In fact, when comparing humans to other extant apes, including chimpanzees, bonobos, gorillas and orangutans, the fascicle length/body mass ratio for the majority of lower limb muscles is decidedly small (Payne et al. 2006). Interestingly, when the PCSA/body mass ratio is compared for the same species and muscles, this characteristic is much larger in humans (Payne et al. 2006). However, because of the greater PCSA we generally possess a larger number of sarcomeres in parallel.
Strength and Speed/Power Athletes
Published in Henry C. Lukaski, Body Composition, 2017
David H. Fukuda, Jay R. Hoffman, Jeffrey R. Stout
With respect to ultrasound-derived muscle morphology, elite 100 m male sprinters possess long fascicle lengths of the vastus lateralis, but smaller pennation angles than distance runners that are comparable to controls (Abe et al. 2000). Female sprinters have comparable vastus lateralis and gastrocnemius fascicle lengths compared to male sprinters, but a smaller pennation angle for the vastus lateralis compared to controls (Abe et al. 2000, 2001; Kumagai et al. 2000). The enhanced shortening velocity of longer fascicle lengths coupled with the smaller physiological cross-sectional area of the thigh musculature, as indicated by the decreased pennation angle, demonstrate the potential for lower-body specific adaptations of sprint athletes (Abe et al. 2000). Male sprinters also have greater muscle thicknesses of both the upper and lower body compared to distance runners and controls (Abe et al. 2000). Interestingly, marked differences in muscle thickness between these groups were found in the most proximal, but not the most distal portion, of the anterior thigh (Abe et al. 2000). The performance implications of these findings will be presented in the next section.
A new musculoskeletal AnyBody™ detailed hand model
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Lucas Engelhardt, Maximilian Melzner, Linda Havelkova, Pavel Fiala, Patrik Christen, Sebastian Dendorfer, Ulrich Simon
Anatomical data were obtained by a study at the UWB by Havelkova et al. (2020b), which included dissecting sixteen cadaveric forearms and Magnetic resonance imaging scans. Through this study, the patient-specific bone surfaces and muscle properties like physiological cross-sectional area (PCSA), muscle length, and origin, via-, and insertion points, as well as the alignment of the muscles were obtained. The whole data set, including a short description of the data obtaining procedure, is freely available (Havelkova et al. 2020a). The means of all values were calculated and implemented into the model. Because the use of mutiple anatomical data can lead to large deviations in the result according to Goislard de Monsabert et al. (2018), the mean values of the sixteen measured samples were calculated and implemented into the model. Further, the muscle alignment was obtained according to the MRI scans of one exemplary cadaver specimen of the anatomical study.
The influence of model parameters on model validation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Benjamin W. Infantolino, Steph E. Forrester, Matthew T.G. Pain, John H. Challis
For the FDIs from each of the cadaver hands pennation angles were measured in both heads using a standard goniometer. As the length of the fascicles varied between samples all pennation angles were referenced to optimum fiber length, this was achieved using a planimetric model of muscle geometry (Otten 1988). In the planar muscle model muscle area remained constant, mirroring the constant volume requirement in muscle (Baskin and Paolini 1966); to achieve this constraint muscle thickness was assumed to remain constant irrespective of fascicle length and therefore other aspects of muscle geometry could be computed (Figure 2). The mass of each muscle was measured to the nearest 0.01 g immediately after dissection, and then used in combination with fiber length and pennation angle to compute muscle physiological cross-sectional area (PCSA; Narici 1999). External tendon length (LT) and muscle belly length were measured to the nearest 0.5 mm using a standard rule and a stereo dissecting microscope at 5x magnification.
The MusIC method: a fast and quasi-optimal solution to the muscle forces estimation problem
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
A. Muller, C. Pontonnier, G. Dumont
The MusIC method was assessed with three different cost functions: two polynomial criteria and one min/max criterion. Other functions usually exploited to evaluate muscle forces could be tested with the MusIC method. It only consists in using a new cost function throughout the database generation. A polynomial criterion with another normalization factor as the physiological cross-sectional area (PCSA) (Crowninshield and Brand 1981) or a soft saturation criterion (Siemienski 1992) could be tested. These cost functions are based on muscle forces or activations. Some authors have proposed to introduce joint reaction forces as a cost (Challis and Kerwin 1993; Dumas et al. 2014). Even if the MusIC method does not take into account directly the joint reaction forces, they are associated to the joint torques. We therefore believe that the use of the MusIC method with this kind of cost function could be an interesting future work. We could also generate the database thanks to cost functions generating co-contraction behaviors (Forster et al. 2004; Brookham et al. 2011). Since the MusIC method aims at mimicking an optimization method, each generated database will lead to a unique solution for a given frame with respect to this cost function. However different databases may be used to generate a variety of solutions, or a unique database containing various solutions.