title: Recovery after heavy resistance exercise and skeletal muscle androgen receptor and insulin-like growth factor-I isoform expression in strength trained men.
abstract: The effects of heavy resistance exercise on skeletal muscle androgen receptor (AR) protein concentration and mRNAs of AR, insulin-like growth factor-I (IGF)-IEa, and mechano growth factor (MGF) expression were examined from biopsies of vastus lateralis (VL) muscle before and 48 hours after heavy resistance exercise (5 × 10 repetition maximum [RM] leg press and 4 × 10RM squats) in 8 adult strength trained men. The present exercise induced an acute decrease in maximal isometric force and increased serum total testosterone (T) and free testosterone (FT) concentrations. During 2 recovery days, maximal isometric force and subjective perception of physical fitness remained significantly lowered, whereas serum creatine kinase activity, subjective muscle soreness, and muscle swelling (i.e., thickness of VL by ultrasound) were significantly increased compared to pre-exercise values. Subjective perception of physical fitness was followed up to 7 days, and by 6 days postexercise, it was elevated above the pre-exercise level. Basal T and FT concentrations remained unaltered after the exercise. No statistically significant changes were observed in AR protein or mRNA expression, but IGF-IEa (p < 0.05) and MGF (p < 0.05) mRNA expression were increased compared to pre-exercise levels. These findings indicate that IGF-IEa and MGF responses may be related to acute regenerative processes in muscle because of exercise and may contribute to muscular adaptation to resistance exercise. Subjective perception of physical fitness suggests that recovery over a pre-exercise level of the present type of heavy resistance exercise can take approximately 6 days.
authors.affiliation: Department of Biology of Physical Activity and Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland. juha.ahtiainen@jyu.fi
authors.forename: Juha P
authors.initials: JP
authors.lastname: Ahtiainen
authors.forename: Maarit
authors.initials: M
authors.lastname: Lehti
authors.forename: Juha J
authors.initials: JJ
authors.lastname: Hulmi
authors.forename: William J
authors.initials: WJ
authors.lastname: Kraemer
authors.forename: Markku
authors.initials: M
authors.lastname: Alen
authors.forename: Kai
authors.initials: K
authors.lastname: Nyman
authors.forename: Harri
authors.initials: H
authors.lastname: Selänne
authors.forename: Arto
authors.initials: A
authors.lastname: Pakarinen
authors.forename: Jyrki
authors.initials: J
authors.lastname: Komulainen
authors.forename: Vuokko
authors.initials: V
authors.lastname: Kovanen
authors.forename: Antti A
authors.initials: AA
authors.lastname: Mero
authors.forename: Keijo
authors.initials: K
authors.lastname: Häkkinen
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D003402:Creatine Kinase / Q000097:blood; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology / Q000523:psychology; D020033:Protein Isoforms / Q000096:biosynthesis / Q000502:physiology; D052097:Quadriceps Muscle / Q000737:chemistry / Q000000981:diagnostic imaging / Q000502:physiology*; D011944:Receptors, Androgen / Q000378:metabolism*; D020127:Recovery of Function / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D050799:STAT5 Transcription Factor / Q000096:biosynthesis / Q000502:physiology; D013739:Testosterone / Q000097:blood; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000502:physiology; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D020033:Protein Isoforms; D011944:Receptors, Androgen; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; D025521:Tumor Suppressor Proteins; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D003402:Creatine Kinase