Recovery from contraction-induced injury is impaired in weight-bearing muscles of old male mice

2006 ◽  
Vol 100 (2) ◽  
pp. 656-661 ◽  
Author(s):  
Erik P. Rader ◽  
John A. Faulkner
Keyword(s):  
Skeletal Muscles ◽  
Weight Bearing ◽  
Maximum Force ◽  
Permanent Damage ◽  
Large Weight ◽  
Adult Mice ◽  
Flexor Muscles ◽  
Isometric Forces ◽  
Old Mice ◽  
Plantar Flexor Muscles

With aging, the skeletal muscles of humans sustain decreases of ∼30% in mass and maximum force. Contraction-induced injury may contribute to these declines. When a 225 lengthening contraction protocol (LCP) was administered to small, non-weight-bearing muscles of mice, muscles of young/adult mice recovered completely, whereas those of old mice sustained permanent deficits of 20% in muscle mass and maximum force. Despite these observations, whether a large, frequently recruited, weight-bearing muscle sustains such permanent damage is not known. The hypothesis tested is that after a severe contraction-induced injury, large, weight-bearing muscles of old mice sustain permanent reductions in mass and force. The LCP was administered to plantar flexor muscles of adult and old, male C57BL/6 mice. At 3 days, 1 mo, and 2 mo after the LCP, maximum isometric forces were measured, anesthetized mice were euthanized, and muscles were removed and weighed. Two months after the LCP, the muscles of the adult mice regained control values of mass and force, whereas for muscles of old mice the mass decreased by 24% and the maximum force decreased by 32%. We conclude that a severe contraction-induced injury to large, weight-bearing muscles of old mice causes permanent deficits in mass and force.

Isometric, shortening, and lengthening contractions of muscle fiber segments from adult and old mice

1994 ◽  
Vol 267 (2) ◽  
pp. C507-C513 ◽  
Author(s):  
S. V. Brooks ◽  
J. A. Faulkner
Keyword(s):  
Muscle Fibers ◽  
Calcium Sensitivity ◽  
Lengthening Contractions ◽  
Adult Mice ◽  
Generating Capacity ◽  
Cross Bridges ◽  
Isometric Forces ◽  
Old Mice ◽  
Shortening Contractions ◽  
Permeabilized Muscle

In old animals, skeletal muscle force decreases during both isometric and shortening contractions. In contrast, force during lengthening appears to be unaffected by aging. We hypothesized that with aging single permeabilized muscle fibers would demonstrate the same impairments in force as are observed for whole muscles. For single permeabilized fibers from extensor digitorum longus muscles of adult and old mice, forces were measured during isometric, shortening, and lengthening contractions performed at 15 degrees C. Maximum isometric forces normalized for fiber area were not different for fibers from adult and old mice. During submaximal isometric contractions a decreased calcium sensitivity resulted in lower forces for fibers from old compared with adult mice. In contrast to a lack of difference in forces developed by fibers from old and adult mice during shortening contractions, during lengthening contractions fibers from old mice developed forces approximately 30% higher than those of adult mice. We conclude that the impairments in force of whole muscles with aging are not the result of impairments in intrinsic force-generating capacity of cross bridges, but changes do occur in single permeabilized muscle fibers of old mice that result in higher forces during stretch.

Comparison of Twitch Contractile Properties of Plantar Flexor Muscles in 9–10-Year-Old Girls and Boys

2003 ◽  
Vol 15 (3) ◽  
pp. 324-332 ◽  
Author(s):  
Mati Pääsuke ◽  
Jaan Ereline ◽  
Helena Gapeyeva ◽  
Madli Toots ◽  
Laivi Toots
Keyword(s):  
Skeletal Muscles ◽  
Relaxation Times ◽  
Voluntary Contraction ◽  
Contractile Properties ◽  
Maximal Rate ◽  
Plantar Flexor ◽  
Postactivation Potentiation ◽  
Flexor Muscles ◽  
Contraction And Relaxation ◽  
Plantar Flexor Muscles

Twitch contractile properties of plantar flexor muscles were compared in 9- to 10-year-old girls and boys. No significant gender differences (p > .05) in isometric maximal voluntary contraction force and twitch peak force, contraction and relaxation times, and twitch maximal rate of force development in either resting or potentiated state have been observed. However, boys had significantly greater (p < .05) twitch postactivation potentiation and potentiated twitch maximal rate of relaxation than girls. These results indicated that twitch force-potentiation capacity of skeletal muscles prior to puberty is more highly developed in boys than girls.

Effect of Contraction History on Torque Deficits by Stretches of Active Rat Skeletal Muscles

2002 ◽  
Vol 27 (4) ◽  
pp. 323-335
Author(s):  
Mark E.T. Willems ◽  
William T. Stauber
Keyword(s):  
Skeletal Muscles ◽  
Muscle Length ◽  
The Other ◽  
Eccentric Contractions ◽  
Isometric Contractions ◽  
Warm Up ◽  
Flexor Muscles ◽  
Maximal Activation ◽  
History Of ◽  
Plantar Flexor Muscles

Effects of contraction history on torque deficits by stretches of active skeletal muscles were examined. After three contractions using maximal and submaximal activation (80 and 20 Hz) at an ankle position of 40° (i.e., long muscle length) and with maximal activation at 120° (i.e., short muscle length), the isometric and stretch torques (15 stretches) of rat plantar flexor muscles (bout 1) were measured. Controls were unconditioned. Stretches (i.e., ankle rotation from 90° to 40°, velocity: 50°•s−1) were imposed on maximal isometric contractions at 90° (i.e. preloaded stretches). All groups performed a second bout following 2 hours of rest after bout 1. After maximal contractions at long muscle length, preload torque at 90° and stretch torque at 40° for stretch 1 of bout 1 were 25% and 18% lower than the other groups. However, for all groups, bout 1 ended and bout 2 began and ended with similar isometric and stretch torques. Stretches early in bout 2, with preloads similar to stretches in bout 1, had greater stretch torques resulting in larger torque deficits. Torque deficits, possibly caused by damage to muscle structures and excitation-contraction uncoupling, were not prevented by a history of isometric contractions. Different contraction histories can result in similar isometric torques but different stretch torques. Key words: injury, warm-up, isometric contractions, prevention, eccentric contractions

scholarly journals Deletion of small ankyrin 1 (sAnk1) isoforms results in structural and functional alterations in aging skeletal muscle fibers

2015 ◽  
Vol 308 (2) ◽  
pp. C123-C138 ◽  
Author(s):  
E. Giacomello ◽  
M. Quarta ◽  
C. Paolini ◽  
R. Squecco ◽  
P. Fusco ◽  
...  
Keyword(s):  
Structural Damage ◽  
Skeletal Muscles ◽  
Functional Characterization ◽  
Sr Proteins ◽  
Endurance Test ◽  
Tubular Aggregates ◽  
Functional Studies ◽  
Old Mice ◽  
Contractile Performance

Muscle-specific ankyrins 1 (sAnk1) are a group of small ankyrin 1 isoforms, of which sAnk1.5 is the most abundant. sAnk1 are localized in the sarcoplasmic reticulum (SR) membrane from where they interact with obscurin, a myofibrillar protein. This interaction appears to contribute to stabilize the SR close to the myofibrils. Here we report the structural and functional characterization of skeletal muscles from sAnk1 knockout mice (KO). Deletion of sAnk1 did not change the expression and localization of SR proteins in 4- to 6-mo-old sAnk1 KO mice. Structurally, the main modification observed in skeletal muscles of adult sAnk1 KO mice (4–6 mo of age) was the reduction of SR volume at the sarcomere A band level. With increasing age (at 12–15 mo of age) extensor digitorum longus (EDL) skeletal muscles of sAnk1 KO mice develop prematurely large tubular aggregates, whereas diaphragm undergoes significant structural damage. Parallel functional studies revealed specific changes in the contractile performance of muscles from sAnk1 KO mice and a reduced exercise tolerance in an endurance test on treadmill compared with control mice. Moreover, reduced Qγcharge and L-type Ca2+current, which are indexes of affected excitation-contraction coupling, were observed in diaphragm fibers from 12- to 15-mo-old mice, but not in other skeletal muscles from sAnk1 KO mice. Altogether, these findings show that the ablation of sAnk1, by altering the organization of the SR, renders skeletal muscles susceptible to undergo structural and functional alterations more evident with age, and point to an important contribution of sAnk1 to the maintenance of the longitudinal SR architecture.

scholarly journals Protein of youth (adventure of a sensation)

2018 ◽  
pp. 78-83
Author(s):  
А.А. Пальцын
Keyword(s):  
Growth Factors ◽  
Old Age ◽  
Skeletal Muscles ◽  
Scientific Community ◽  
Harvard University ◽  
Transforming Growth Factors ◽  
Tissue Concentrations ◽  
Mammalian Blood ◽  
Old Mice ◽  
Reliable Methods

Группа исследователей из Гарвардского университета в 2013 и последующих годах опубликовала серию статей об одном из трансформирующих факторов роста b - GDF-11. По данным этого коллектива, концентрация GDF-11 в крови и тканях млекопитающих с возрастом снижается. Искусственное повышение содержания GDF-11 у старых мышей путем ежедневных инъекций рекомбинантного GDF-11 или парабиоза в течение месяца с молодыми мышами существенно снижало и даже устраняло свойственные старости неблагоприятные изменения сердца, скелетных мышц, мозга. Статьи Гарвардской группы привлекли большое внимание научного сообщества, были комментированы в сотнях публикаций, и в них GDF-11 стали часто называть белком молодости. Капитальность заявки Гарварда стимулировала капитальность проверочных экспериментов с привлечением максимально надежных методик. Эти эксперименты расширили знания о GDF-11, но не подтвердили его права называться белком молодости. A research group at the Harvard University in 2013 and the next years has published a series of articles focusing on one of transforming growth factors b, GDF-11. According to these reports mammalian blood and tissue concentrations of GDF-11 decrease with age. Increasing the GDF-11 content in old mice using daily injections of recombinant GDF-11 or one-month parabiosis induced in young mice significantly reduced and even eliminated adverse, old age-specific changes in the heart, skeletal muscles, and brain. The reports of the Harvard group have attracted much attention of the scientific community, and were cited in hundreds of publications where GDF-11 was often called the protein of youth. The solidity of the Harvard team statement warranted solidity of test experiments, which used the most reliable methods. These experiments have expanded the knowledge of GDF-11 but did not confirm its right to be called a protein of youth.

scholarly journals Ultrasound-derived changes in thickness of human ankle plantar flexor muscles during walking and running are not homogeneous along the muscle mid-belly region

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. F. Hodson-Tole ◽  
A. K. M. Lai
Keyword(s):  
Statistical Parametric Mapping ◽  
Muscle Thickness ◽  
Ultrasound Images ◽  
Plantar Flexor ◽  
Image Region ◽  
Thickness Change ◽  
Musculoskeletal Models ◽  
Flexor Muscles ◽  
Anatomical Space ◽  
Plantar Flexor Muscles

Abstract Skeletal muscle thickness is a valuable indicator of several aspects of a muscle’s functional capabilities. We used computational analysis of ultrasound images, recorded from 10 humans walking and running at a range of speeds (0.7–5.0 m s−1), to quantify interactions in thickness change between three ankle plantar flexor muscles (soleus, medial and lateral gastrocnemius) and quantify thickness changes at multiple muscle sites within each image. Statistical analysis of thickness change as a function of stride cycle (1d statistical parametric mapping) revealed significant differences between soleus and both gastrocnemii across the whole stride cycle as they bulged within the shared anatomical space. Within each muscle, changes in thickness differed between measurement sites but not locomotor condition. For some of the stride, thickness measures taken from the distal-mid image region represented the mean muscle thickness, which may therefore be a reliable region for these measures. Assumptions that muscle thickness is constant during a task, often made in musculoskeletal models, do not hold for the muscles and locomotor conditions studied here and researchers should not assume that a single thickness measure, from one point of the stride cycle or a static image, represents muscle thickness during dynamic movements.

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