{"c9d6af7c2177e721a536dbca7891c9f5inspo5":{"DOI":"10.1002/mrm.26329","ISBN":"","ISSN":"","URL":"https://doi.org/10.1002%2Fmrm.26329","abstract":"Purpose\nThe aim of the study was to examine pH heterogeneity during fatigue induced by neuromuscular electrical stimulation (NMES) using phosphorus magnetic resonance spectroscopy (31P-MRS). It is hypothesized that three pH components would occur in the 31P-MRS during fatigue, representing three fiber types.\n\nMethods\nThe medial gastrocnemius of eight subjects was stimulated within a 3-Tesla whole body MRI scanner. The maximal force during stimulation (Fstim) was examined by a pressure sensor. Phosphocreatine (PCr), adenosintriphosphate, inorganic phosphate (Pi), and the corresponding pH were estimated by a nonvolume-selective 31P-MRS using a small loop coil at rest and during fatigue.\n\nResults\nDuring fatigue, Fstim and PCr decreased to 27% and 33% of their initial levels, respectively. In all cases, the Pi peak increased when NMES was started and split into three different peaks. Based on the single Pi peaks during fatigue, an alkaline (6.76 ± 0.08), a medium (6.40 ± 0.06), and an acidic (6.09 ± 0.05) pH component were observed compared to the pH (7.02 ± 0.02) at rest.\n\nConclusion\nIt is suggested that NMES is able to induce pH heterogeneity in the medial gastrocnemius, and that the single Pi peaks represent the different muscle fiber types of the skeletal muscle. Magn Reson Med 77:2097–2106, 2017. © 2016 International Society for Magnetic Resonance in Medicine","annote":"","author":[{"family":"Stutzig","given":"Norman"},{"family":"Rzanny","given":"Reinhard"},{"family":"Moll","given":"Kevin"},{"family":"Gussew","given":"Alexander"},{"family":"Reichenbach","given":"Jürgen R."},{"family":"Siebert","given":"Tobias"}],"citation-label":"Stutzig_2016","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Magnetic Resonance in Medicine","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2016","07"]],"literal":"2016"},"event-place":"","id":"c9d6af7c2177e721a536dbca7891c9f5inspo5","interhash":"ca3646b5a6e2d9164e4872324a5321c4","intrahash":"c9d6af7c2177e721a536dbca7891c9f5","issue":"6","issued":{"date-parts":[["2016","07"]],"literal":"2016"},"keyword":"components fatigue neuromuscular electrical pH during MRS heterogeneity three stimulation","misc":{"doi":"10.1002/mrm.26329"},"note":"","number":"6","number-of-pages":"9","page":"2097--2106","page-first":"2097","publisher":"Wiley","publisher-place":"","status":"","title":"The pH heterogeneity in human calf muscle during neuromuscular electrical stimulation","type":"article-journal","username":"inspo5","version":"","volume":"77"},"9f4dc155ee7bcd9d0f62512194889cb6inspo5":{"DOI":"10.1016/j.jmbbm.2015.06.026","ISBN":"","ISSN":"","URL":"https://doi.org/10.1016%2Fj.jmbbm.2015.06.026","abstract":"There are several studies dealing with experimental and structural analyses of skeletal muscles that are aimed at gaining a better understanding of three-dimensional muscle deformation and force generation. A variety of these contributions have performed structural or mechanical analyses, but very few have combined these approaches at different levels. To fill this gap, the present study aims to bring together three-dimensional micro-structural and mechanical findings in rabbit M. plantaris to study load transfer mechanisms inside the muscle during passive loading and active muscle contraction. During these two deformation states, the three-dimensional surface of the aponeurosis–tendon complex was recorded using optical measurement systems. In this way, the strain distribution on the muscle can be calculated to interpret the load transfer mechanisms inside the muscle. The results show that the three-dimensional strain distribution during muscle activation is completely different from the distribution during passive loading. Under both loading conditions, the strain distribution is irregular. To interpret these findings, the gross try and the fascicle architecture of the M. plantaris were determined. In doing so, a highly complex microstructure featuring tube- and sail-like structure was identified. Moreover, a compartmentalisation of the muscle into two compartments was detected. The smaller, bipennated muscle compartment was embedded into the larger, unipennated compartment. To the authors׳ knowledge, this type of inner structure has never been previously documented in single-headed muscles.","annote":"","author":[{"family":"Böl","given":"Markus"},{"family":"Leichsenring","given":"Kay"},{"family":"Ernst","given":"Michael"},{"family":"Wick","given":"Carolin"},{"family":"Blickhan","given":"Reinhard"},{"family":"Siebert","given":"Tobias"}],"citation-label":"B_l_2015","collection-editor":[{"family":"Siebert","given":"Tobias"}],"collection-title":"","container-author":[{"family":"Siebert","given":"Tobias"}],"container-title":"Journal of the Mechanical Behavior of Biomedical Materials","documents":[],"edition":"","editor":[{"family":"Siebert","given":"Tobias"}],"event-date":{"date-parts":[["2015","11"]],"literal":"2015"},"event-place":"","id":"9f4dc155ee7bcd9d0f62512194889cb6inspo5","interhash":"64f8172e44e7d9861aedc00fa7c391fb","intrahash":"9f4dc155ee7bcd9d0f62512194889cb6","issue":"","issued":{"date-parts":[["2015","11"]],"literal":"2015"},"keyword":"M. morphology like dimensional plantarisSail complex Rabbit Three structure tendon Aponeurosis muscle Muscle architecture","misc":{"language":"English","doi":"10.1016/j.jmbbm.2015.06.026"},"note":"","number":"","number-of-pages":"14","page":"25--39","page-first":"25","publisher":"Elsevier BV","publisher-place":"","status":"","title":"Novel microstructural findings in M. plantaris and their impact during active and passive loading at the macro level","type":"article-journal","username":"inspo5","version":"","volume":"51"}}