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Muscle fiber size in healthy children and adults in relation to sex and fiber types
Author(s) -
Esbjörnsson Mona E.,
Dahlström Monica S.,
Gierup Jan W.,
Jansson Eva Ch.
Publication year - 2021
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.27151
Subject(s) - fiber type , muscle biopsy , myofibril , fiber , muscle fibre , young adult , vastus lateralis muscle , medicine , percutaneous biopsy , physiology , endocrinology , anatomy , biopsy , skeletal muscle , chemistry , organic chemistry
Background In adult males, cross‐sectional area (CSA) for type II muscle fibers is generally larger than for type I fibers. In this cross‐sectional study the aim was to compare sex‐related CSAs of various muscle fiber types during childhood‐to‐adulthood transition. Methods Percutaneous biopsy samples were obtained from vastus lateralis in 10‐y‐old children (10 males and 5 females) and in young adults (9 males and 7 females). Fiber types were classified by myofibrillar ATPase and CSAs from NADH‐dehydrogenase staining. Results Type IIA were larger than type I fibers in adult males, but not in adult females or children (age x sex x fiber type, P < .002). When including all participants, body weight and sex explained 78% of the variation in type IIA CSA but only body weight contributed for type I. Conclusions Sex‐specific patterns in CSA of the muscle fiber types appears to develop during the transition from childhood to adulthood.