Skeletal muscle fiber‐type‐specific changes in markers of capillary and mitochondrial content after low‐volume interval training in overweight women

Skeletal muscle fiber‐type‐specific changes in markers of capillary and mitochondrial content... High‐intensity interval training (HIIT) enhances skeletal muscle oxygen delivery and utilization but data are limited regarding fiber‐specific adaptations in humans. We examined the effect of 18 sessions of HIIT (10 × 60‐sec cycling intervals at ~90% HRmax, interspersed by 60‐sec of recovery) over 6 weeks on markers of microvascular density and oxidative capacity in type I and II fibers in healthy but sedentary young women (Age: 26 ± 7 years; BMI: 30 ± 4 kg·m−2; VO2peak: 2.16 ± 0.45 L·m−1). Immunohistochemical analyses of muscle cross sections revealed a training‐induced increase in capillary contacts per fiber in type I fibers (PRE: 4.38 ± 0.37 vs. POST: 5.17 ± 0.80; main effect, P < 0.05) and type II fibers (PRE: 4.24 ± 0.55 vs. POST: 4.92 ± 0.54; main effect, P < 0.05). The capillary‐to‐fiber ratio also increased after training in type I fibers (PRE: 1.53 ± 1.44 vs. POST: 1.88 ± 0.38; main effect, P < 0.05) and type II fibers (PRE: 1.45 ± 0.19 vs. POST: 1.76 ± 0.27; main effect, P < 0.05). Muscle oxidative capacity as reflected by the protein content of cytochrome oxidase IV also increased after training in type I fibers (PRE: 3500 ± 858 vs. POST: 4442 ± 1377 arbitrary units; main effect, P < 0.01) and type II fibers (PRE: 2632 ± 629 vs. POST: 3863 ± 1307 arbitrary units; main effect, P < 0.01). We conclude that short‐term HIIT in previously inactive women similarly increases markers of capillary density and mitochondrial content in type I and type II fibers. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Physiological Reports Wiley

Skeletal muscle fiber‐type‐specific changes in markers of capillary and mitochondrial content after low‐volume interval training in overweight women

Loading next page...
 
/lp/wiley/skeletal-muscle-fiber-type-specific-changes-in-markers-of-capillary-cn6ionCv6d
Publisher
Wiley Subscription Services, Inc., A Wiley Company
Copyright
© 2018 Published by the American Physiological Society and The Physiological Society
ISSN
2051-817X
eISSN
2051-817X
D.O.I.
10.14814/phy2.13597
Publisher site
See Article on Publisher Site

Abstract

High‐intensity interval training (HIIT) enhances skeletal muscle oxygen delivery and utilization but data are limited regarding fiber‐specific adaptations in humans. We examined the effect of 18 sessions of HIIT (10 × 60‐sec cycling intervals at ~90% HRmax, interspersed by 60‐sec of recovery) over 6 weeks on markers of microvascular density and oxidative capacity in type I and II fibers in healthy but sedentary young women (Age: 26 ± 7 years; BMI: 30 ± 4 kg·m−2; VO2peak: 2.16 ± 0.45 L·m−1). Immunohistochemical analyses of muscle cross sections revealed a training‐induced increase in capillary contacts per fiber in type I fibers (PRE: 4.38 ± 0.37 vs. POST: 5.17 ± 0.80; main effect, P < 0.05) and type II fibers (PRE: 4.24 ± 0.55 vs. POST: 4.92 ± 0.54; main effect, P < 0.05). The capillary‐to‐fiber ratio also increased after training in type I fibers (PRE: 1.53 ± 1.44 vs. POST: 1.88 ± 0.38; main effect, P < 0.05) and type II fibers (PRE: 1.45 ± 0.19 vs. POST: 1.76 ± 0.27; main effect, P < 0.05). Muscle oxidative capacity as reflected by the protein content of cytochrome oxidase IV also increased after training in type I fibers (PRE: 3500 ± 858 vs. POST: 4442 ± 1377 arbitrary units; main effect, P < 0.01) and type II fibers (PRE: 2632 ± 629 vs. POST: 3863 ± 1307 arbitrary units; main effect, P < 0.01). We conclude that short‐term HIIT in previously inactive women similarly increases markers of capillary density and mitochondrial content in type I and type II fibers.

Journal

Physiological ReportsWiley

Published: Jan 1, 2018

Keywords: ; ; ; ;

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial