Human soleus single muscle fiber function with exercise or nutrition countermeasures during 60 days of bed rest

Trappe, Scott; Creer, Andrew; Minchev, Kiril; Slivka, Dustin; Louis, Emily; Luden, Nicholas D.; Trappe, Todd A.

doi:10.1152/ajpregu.00761.2007

Cited by 73 publications

(83 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A similar influence of aerobic training on myofiber contraction velocity has been consistently shown in human (14,19,47,58) and rodent models (36). The mechanism by which aerobic training increases contraction velocity is unclear, but may be related to MLC morphology (36,57), although this relationship is tenuous in human skeletal muscle (26,44,46,50). Interestingly, we observed a reduction in MLC 1s with a nonsignificant (P Ͼ 0.05) increase in MLC 3f , which may partially explain the elevation in contraction velocity after training.…”

Section: Discussionmentioning

confidence: 52%

Aerobic exercise training improves whole muscle and single myofiber size and function in older women

Harber

Konopka

Douglass

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

195

206

View full text Add to dashboard Cite

Harber MP, Konopka AR, Douglass MD, Minchev K, Kaminsky LA, Trappe TA, Trappe S. Aerobic exercise training improves whole muscle and single myofiber size and function in older women. Am J Physiol Regul Integr Comp Physiol 297: R1452-R1459, 2009. First published August 19, 2009 doi:10.1152/ajpregu.00354.2009.-To comprehensively assess the influence of aerobic training on muscle size and function, we examined seven older women (71 Ϯ 2 yr) before and after 12 wk of cycle ergometer training. The training program increased (P Ͻ 0.05) aerobic capacity by 30 Ϯ 6%. Quadriceps muscle volume, determined by magnetic resonance imaging (MRI), was 12 Ϯ 2% greater (P Ͻ 0.05) after training and knee extensor power increased 55 Ϯ 7% (P Ͻ 0.05). Muscle biopsies were obtained from the vastus lateralis to determine size and contractile properties of individual slow (MHC I) and fast (MHC IIa) myofibers, myosin light chain (MLC) composition, and muscle protein concentration. Aerobic training increased (P Ͻ 0.05) MHC I fiber size 16 Ϯ 5%, while MHC IIa fiber size was unchanged. MHC I peak power was elevated 21 Ϯ 8% (P Ͻ 0.05) after training, while MHC IIa peak power was unaltered. Peak force (Po) was unchanged in both fiber types, while normalized force (Po/cross-sectional area) was 10% lower (P Ͻ 0.05) for both MHC I and MHC IIa fibers after training. The decrease in normalized force was likely related to a reduction (P Ͻ 0.05) in myofibrillar protein concentration after training. In the absence of an increase in Po, the increase in MHC I peak power was mediated through an increased (P Ͻ 0.05) maximum contraction velocity (Vo) of MHC I fibers only. The relative proportion of MLC1s (Pre: 0.62 Ϯ 0.01; Post: 0.58 Ϯ 0.01) was lower (P Ͻ 0.05) in MHC I myofibers after training, while no differences were present for MLC 2s and MLC 3f isoforms. These data indicate that aerobic exercise training improves muscle function through remodeling the contractile properties at the myofiber level, in addition to pronounced muscle hypertrophy. Progressive aerobic exercise training should be considered a viable exercise modality to combat sarcopenia in the elderly population.

show abstract

Section: Discussionmentioning

confidence: 52%

Aerobic exercise training improves whole muscle and single myofiber size and function in older women

Harber

Konopka

Douglass

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

195

206

View full text Add to dashboard Cite

show abstract

“…The design included women who were part of previous research conducted in our laboratory, where both the soleus and vastus lateralis skeletal muscles were concomitantly investigated. One subgroup was previously examined for their whole muscle and single-fiber functional response to 60 days of bed rest (32,37,38). The single-muscle fiber data included in this investigation were derived from the pre bed rest time point and were generated as part of a much larger study conducted at the Institute for Space Physiology and Medicine in Toulouse, France.…”

Section: Experimental Design and Subject Profilementioning

confidence: 99%

“…A video camera (CCD-IRIS, DXC-107A; Sony) connected to the microscope and interfaced to a computer allowed viewing on a computer monitor and storage of the digitized images of the muscle fibers during the experiment. Fiber diameter was determined from a captured computer image taken with the fiber briefly suspended in air (Ͻ3 s) (37,38). Fiber width (diameter) was determined at 3 points along the length of the captured computer image using National Institutes of Health public domain software (Scion Image, release Beta 4.0.2, for Windows).…”

Section: Single Muscle Fiber Analysismentioning

confidence: 99%

“…These studies have provided us with the unique opportunity to combine data from a large number of women (n ϭ 27; Ͼ900 individual human single fibers) in an effort to make a direct comprehensive comparison of the single muscle fiber function between soleus and vastus lateralis muscles. Because of dissimilar daily activity patterns between the soleus and vastus lateralis muscles and their differential responses to unloading (32,37,38) and exercise (39), we tested the hypothesis that both size and contractile function differ between vastus lateralis and soleus single fibers, within MHC I and IIa fiber populations.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Human vastus lateralis and soleus muscles display divergent cellular contractile properties

Luden¹,

Minchev²,

Hayes³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

View full text Add to dashboard Cite

The purpose of this study was to investigate potential differences in single-fiber contractile physiology of fibers with the same myosin heavy chain isoform (MHC I and MHC IIa) originating from different muscles. Vastus lateralis (VL) and soleus biopsies were obtained from 27 recreationally active females (31 Ϯ 1 yr, 59 Ϯ 1 kg). A total of 943 single fibers (MHC I ϭ 562; MHC IIa ϭ 301) were isolated and examined for diameter, peak tension (Po), shortening velocity (Vo), and power. The soleus had larger (P Ͻ 0.05) fibers (MHC I ϩ18%; MHC IIa ϩ19%), higher MHC I Vo (ϩ13%), and higher MHC I Po (ϩ18%) compared with fibers from the VL. In contrast, fibers from the VL had higher (P Ͻ 0.05) specific tension (MHC I ϩ18%; MHC IIa ϩ20%), and MHC I normalized power (ϩ25%) compared with the soleus. There was a trend for MHC IIa soleus fibers to have higher Vo [MHC IIa ϩ13% (P ϭ 0.058)], whereas VL MHC IIa fibers showed a trend for higher normalized power compared with soleus fibers [MHC IIa ϩ33% (P ϭ 0.079)]. No differences in absolute power were detected between muscles. These data highlight muscle-specific differences in single-fiber contractile function that should serve as a scientific basis for consideration when extending observations of skeletal muscle tissue from one muscle of interest to other muscles of origin. This is important when examining skeletal muscle adaptation to physical states such as aging, unloading, and training. skeletal muscle; muscle plasticity APPLICATION OF THE NEEDLE biopsy technique has allowed scientists to better characterize human skeletal muscle over the course of the last four decades (2, 3). Some of the more commonly investigated muscles include the gastrocnemius, deltoid, vastus lateralis, and soleus. From this research the functional diversity of skeletal muscle has been well documented. For instance, the three primary myosin heavy chain (MHC) isoforms identified in human skeletal muscle (30) (i.e., MHC I, MHC IIa, and MHC IIx) display contrasting metabolic (27a) and contractile properties (5). Consequently, whole muscle, which is composed of multiple MHC isoforms, has the ability to perform within a functional continuum influenced by relative fiber-type distribution. Although fiber-type distribution can substantially vary between muscles from an individual (19) (e.g., soleus and vastus lateralis), little is known about the functional differences that may exist within a fiber-type population from different muscles of origin (4).Physical activity has repeatedly been shown to induce alterations in single muscle fiber contractile physiology (11,15,20,31,34,36,40). Therefore, two leg muscles with distinctly different daily loading demands (9), much like the vastus lateralis and soleus, could have disparate contractile profiles. To our knowledge, only two human single-fiber studies have made a direct functional comparison between fibers containing the same MHC isoform obtained from different muscles (17,41). While the original inquiry did not detect differences between vastus lateralis and...

show abstract

“…Data on the use of high resistance exercises with high intensity confirms their importance in the protection of muscle function from atrophy. Thus, balanced PT consisting of high resistance and intense exercises (2-3 days/week) and aerobic exercises (~4 days/week) is more effective in the preservation of muscle function during prolonged bed rest (Trappe et al 2007(Trappe et al , 2008(Trappe et al , 2009. Moreover, training with highly intensive resistance exercises lasting for ~7 min/ week during the bed rest period was more effective when compared to exercises lasting for more than 60 min/week under actual zero gravity conditions (Trappe et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Influence of Simulated Microgravity on Mechanical Properties in the Human Triceps Surae Muscle in vivo

Koryak

2015

Central European Journal of Sport Sciences and Medicine

View full text Add to dashboard Cite

Abstract. Purpose. The aim of the study was to investigate the effects of a simulated microgravity on the mechanical properties of the human triceps surae (TS) and to assess the effectiveness of physical training (PT) in preventing detrimental effects. Methods. Eight women (aged 26-36 years) underwent 120-d of Bed rest (BR): four underwent Bed rest only (BR group) and four performed PT during this period (BRPT group). The training sessions were conducted for 60 min each day for 6 days a week for 14 weeks, and 30-40 min twice a day for 2 weeks under the experiment conditions. PT was performed over a 4-d cycle: 3-d of training and 1-d of rest. The maximal voluntary contraction (MVC), and isometric twitch contraction (P t ), and electrically evoked tetanic tension at 150 impulses × s -1 (Р о ), time-to-peak tension (TPT) of the twitch were determined. The difference between Р о and MVC expressed as a percentage of Р о and referred to a force deficiency (Р d ). The MTS was determined according to the electromechanical delay (EMD) value during the explosive voluntary contraction. Surface electrodes sensed electromyographic (EMG) activity in the soleus muscle. Electromechanical delay (EMD) was the time interval between the change in EMG and movement muscle force production. Results. In the BR group, Р t , MVC, and Р о had decreased by 12, 36, 24%, respectively, but Р d had increased by 39%. TPT of the twitch had increased by 14%. The rate of increase of voluntary contractions reduced, but in the electrically evoked contraction no changes were observed. The EMD had increased by 27%. In the BREx group, МVС, Р t , and Р о decreased by 3%, and 14%, and 9%, respectively. TPT had decreased by 4%. The P d had decreased significantly by 10%. The rate of rise increase of electrically evoked tetanic did not change significantly, but the rate of rise in isometric voluntary tension development was increased. The EMD had decreased by 12%. Conclusion. Unloading decreased function and EMD muscle and, although the PT did attenuate these effects, they did not completely prevent them. It is suggested that the total loading volume (mainly its intensity) was not sufficient to completely prevent alterations in tendon mechanical properties

show abstract

Human soleus single muscle fiber function with exercise or nutrition countermeasures during 60 days of bed rest

Cited by 73 publications

References 61 publications

Aerobic exercise training improves whole muscle and single myofiber size and function in older women

Aerobic exercise training improves whole muscle and single myofiber size and function in older women

Human vastus lateralis and soleus muscles display divergent cellular contractile properties

Influence of Simulated Microgravity on Mechanical Properties in the Human Triceps Surae Muscle in vivo

Contact Info

Product

Resources

About