Human PhysiologyHuman PhysiologyФизиология человека0131-16463034-6150The Russian Academy of Sciences66398010.31857/S0131164622600604GBPFFIArticlesСтатьиDynamics of Changes in Muscle Architecture, Force, Strength-Velocity Properties of the Muscles of Lower Limbs in Humans under the Influence of a Three Week UnloadingИзменение функций и архитектуры скелетной мышцы у человека под влиянием 21-суточной разгрузки двигательного аппарата без физической тренировкиKoryakYu. A.КорякЮ. А.yurikoryak@mail.ruKukobaT. B.КукобаТ. Б.yurikoryak@mail.ruBabichD. R.БабичД. Р.yurikoryak@mail.ruInstitute of Biomedical Problems of the RASФГБУН ГНЦ РФ – Институт медико-биологических проблем РАН01032023492274325022025Copyright ©; 2023, Ю.А. Коряк, Т.Б. Кукоба, Д.Р. БабичCopyright ©; 2023, Ю.А. Коряк, Т.Б. Кукоба, Д.Р. Бабич2023Ю.А. Коряк, Т.Б. Кукоба, Д.Р. БабичЮ.А. Коряк, Т.Б. Кукоба, Д.Р. Бабичhttps://journals.eco-vector.com/0131-1646/article/view/663980

The present study examined the hypothesis that significant alterations in antigravity muscle architecture would occur with dry water immersion (DI) and that some structural changes may be seen in postural muscles because of the overall decrease in physical activity. Ten men (age (mean ± SE) – 24.5 ± 3.9 years, height – 176.1 ± 1.2 m, mass – 71.1 ± 3.4 kg) volunteered for the study. The healthy men underwent of DI for 21 days. All subjects did not use physical training during the exposure. The contractile properties of the muscle ankle extensors and flexors (maximal voluntary contraction (MVC) and strength-velocity relationship) were evaluated using an isokinetic dynamometer. The internal architecture of the triceps surae muscle of its two heads (medial (MG) and lateral (LG) gastrocnemius muscles) was determined by in vivo ultrasound (US) at ankle angles of –15° (dorsiflexion), 0° (neutral anatomical position), and +30° (plantarflexion) with an angle in the knee joint of 0°. In each position, longitudinal US of MG and LG were obtained at the proximal levels 30% (MG and LG) of the distance between the popliteal crease and the center of the lateral malleolus. US images were detected at rest for each ankle position, and the fiber length (Lf) and pennation angle (Θf) relative to the aponeurosis were determined. After DI the MVC muscle ankle extensors decreased from 122.6 ± 43.1 to 99.5 ± 22.7 N (19%). Although there was a significant no change in dorsiflexion. After DI with the ankle angle increasing from –15° to +30°, Lf changes from 43 ± 1 to 32 ± 2 mm (25.6%, p < 0.01) for MG and from 45 ± 2 to 34 ± 1 mm (24.4%, p < 0.01) for LG, and Θf increased from 21° ± 1° to 26° ± 2° (23.8%) for MG and from 14° ± 1° to 18° ± 2° (28.6%) for LG. Collectively, the present data suggest that the architecture and contractile capacity of human pennate muscle are interrelated, in vivo. The finding that amongst the antigravity muscles, the MG deteriorated to a greater extent than the LG is possibly related to the differences in relative load that this muscle possibly experiences during daily loading. Different Lf and Θf, and their changes by after unloading, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses. Structural muscle changes can be considered as an adaptive process, in response to disuse.

В настоящем исследовании была рассмотрена гипотеза о том, что значительные изменения в архитектуре антигравитационных мышц могут произойти при экспозиции в условиях продолжительной “сухой” водной иммерсии (СИ) и, из-за общего снижения физической активности могут наблюдаться некоторые структурные изменения в постуральных мышцах. Десять мужчин-добровольцев (возраст (средняя ± средняя ошибка) – 24.5 ± 3.9 года, рост – 176.1 ± 1.2 м, масса – 71.1 ± 3.4 кг)) приняли участия в исследовании влияния 21-суточной разгрузки мышечного аппарата в условиях СИ. Во время экспозиции испытуемые не использовали физическую тренировку. Сократительные свойства мышц-разгибателей и сгибателей стопы (максимальная произвольная сила (МПС) и отношение сила-скорость) оценивали с использованием изокинетического динамометра. Внутреннюю архитектуру двух головок трехглавой мышцы голени (медиальной (МИМ) и латеральной (ЛИМ) икроножных мышц) определяли методом ультразвуковой визуализации в условиях in vivo при углах голеностопного сустава –15° (тыльное сгибание), 0° (нейтральная анатомическая позиция) и +30° (подошвенное сгибание) с углом в коленном суставе 180°. В каждой позиции были получены продольные ультразвуковые изображения (УЗИ) МИМ и ЛИМ на проксимальных уровнях 30% расстоянии между подколенной складкой и центром латеральной лодыжки. УЗИ были получены в состоянии покоя при каждой позиции голеностопного сустава с определением длины волокна (Lв) и угла наклона (Θв) мышечных волокон относительно их апоневроза. После СИ МПС мышц-разгибателей стопы снизилась в среднем на 19% (до 122.6 ± 43.1 Нм, после 99.5 ± 22.7 Нм), но не обнаружено значительных изменений в мышцах-сгибателей стопы. При изменении угла в голеностопном суставе с –15° до +30° Lв изменялась с 43 ± 1 до 32 ± 2 мм (25.6%, p < 0.01) в МИМ и с 45 ± 2 до 34 ± 1 мм (24.4%, p < 0.01) для ЛИМ и Θв увеличивался с 21° ± 1° до 26° ± 2° (23.8%) в МИМ и с 14° ± 1° до 18° ± 2° (28.6%) в ЛИМ. Данные позволяют предположить, что архитектура и функция перистых мышц человека взаимосвязаны in vivo. Большие изменения в антигравитационной МИМ по сравнению с ЛИМ, возможно, связаны с различиями в относительной нагрузке этих мышц во время ежедневной активности. Различные Lв и Θв и их изменения после разгрузки могут быть связаны с различиями в силовых способностях мышц и эластических характеристиках сухожилий и апоневрозов. Структурные мышечные изменения можно рассматривать как адаптационный процесс в ответ на неиспользование.

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