HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 105/6/1845    most recent 90445.2008v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Christensen, B. Articles by Langberg, H. Search for Related Content PubMed PubMed Citation Articles by Christensen, B. Articles by Langberg, H.

Short-term immobilization and recovery affect skeletal muscle but not collagen tissue turnover in humans

¹Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Faculty of Health Sciences, University of Copenhagen, Copenhagen; and ²Institute of Sports Exercise and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark

Submitted 26 March 2008 ; accepted in final form 12 October 2008

Not much is known about the effects of immobilization and subsequent recovery on tendon connective tissue. In the present study, healthy young men had their nondominant leg immobilized for a 2-wk period, followed by a recovery period of the same length. Immobilization resulted in a mean decrease of 6% (5,413 to 5,077 mm²) in cross-sectional area (CSA) of the triceps surae muscles and a mean decrease of 9% (261 to 238 N·m) in strength of the immobilized calf muscles. Two weeks of recovery resulted in a 6% increased in CSA (to 5,367 mm²), whereas strength remained suppressed (240 N·m). No difference in Achilles tendon CSA was detected between the two legs at any time point. Local tendon collagen synthesis, measured as the peritendinous concentrations of PINP (NH₂-terminal propeptide of type I collagen; indirect marker for collagen synthesis), was unchanged after 2 wk of immobilization. However, peritendinous levels of PINP were significantly elevated in the immobilized leg (15 to 139 ng/ml) following 2 wk of remobilization compared with preimmobilization levels. In contradiction hereto, systemic concentrations of PINP remained unchanged throughout the study. Immobilization reduced muscle size and strength, while tendon size and collagen turnover were unchanged. While recovery resulted in an increase in muscle size, strength was unchanged. No significant difference in tendon size could be detected between the two legs after 2 wk of recovery, although collagen synthesis was increased in the previously immobilized leg. Thus 2 wk of immobilization are sufficient to induce significant changes in muscle tissue, whereas tendon tissue seems to be more resistant to short-term immobilization.

collagen type I turnover; disuse; muscle strength; cross-sectional area