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This Article Full Text Full Text (PDF) All Versions of this Article: 90/2/215    most recent expphysiol.2004.028258v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal 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 Elliott, K. J. Articles by Diver, M. Search for Related Content PubMed PubMed Citation Articles by Elliott, K. J. Articles by Diver, M. Related Collections Muscle

¹ Applied Biomedical Research Group, King's College London ² Research Institute for Sport and Exercise Sciences, Liverpool John Moores University³ Reproductive Medicine Unit, Liverpool Women's Hospital ⁴ Department of Clinical Chemistry, The University of Liverpool

The purpose of this study was to investigate the effects of supra-physiological changes in ovarian hormone levels on maximum force production in two conditions, one physiological (pregnancy) and one pseudo-physiological (in vitro fertilization (IVF) treatment). Forty IVF patients were tested at four distinct stages of treatment and 35 women were tested during each trimester of pregnancy and following parturition. Maximum voluntary isometric force per unit cross-sectional area of the first dorsal interosseus muscle was measured. Plasma concentrations of total and bioavailable oestradiol and testosterone were measured, in addition to the total concentrations of progesterone and human chorionic gonadotropin. Despite significant changes in the concentrations of total progesterone, 17ß-oestradiol, bioavailable oestradiol and testosterone between phases, strength did not change significantly throughout IVF treatment (1.30 ± 0.29, 1.16 ± 0.38, 1.20 ± 0.29 and 1.26 ± 0.34 N mm^–2, respectively, in the 4 phases of IVF treatment). Force production was significantly higher during the second trimester of pregnancy than following childbirth (1.33 ± 0.20 N mm^–2 at week 12 of pregnancy, 1.51 ± 0.42 N mm^–2 at week 20, 1.15 ± 0.26 N mm^–2 at week 36 and 0.94 ± 0.31 N mm^–2 at week 6 postnatal) but was not significantly correlated with any of the hormones measured. These data suggest that extreme changes in the concentrations of reproductive hormones do not affect the maximum force-generating capacity of young women.

(Received 8 June 2004; accepted after revision 16 November 2004; first published online 30 November 2004)
Corresponding author K. J. Elliott: Applied Biomedical Sciences Research Group, GKT School of Biomedical Sciences, Shepherds House, Kings College London, Guys Campus, London SE1 1UL, UK. Email: kirsty.elliott{at}kcl.ac.uk