Resistance exercise-induced increase in muscle mass correlates with p70S6 kinase phosphorylation in human subjects

• Published in: European journal of applied physiology Vol. 102; no. 2; pp. 145 - 152
• Main Authors: Terzis, Gerasimos, Georgiadis, Giorgos, Stratakos, Grigoris, Vogiatzis, Ioannis, Kavouras, Stavros, Manta, Panagiota, Mascher, Henrik, Blomstrand, Eva
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.01.2008; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedicine; Biopsy; Enzymes; Exercise; Exercise - physiology; Exercise Test; Fysiologi; Fysiologi och farmakologi; Health care; Human Physiology; Human subjects; Humans; Kinases; Male; MEDICIN; MEDICINE; Muscle Contraction - physiology; Muscle, Skeletal - anatomy & histology; Muscle, Skeletal - physiology; Musculoskeletal system; Occupational Medicine/Industrial Medicine; Original Article; Phosphorylation; Physical education; Physical Exertion - physiology; Physiology; Physiology and pharmacology; Protein synthesis; Proteins; Ribosomal Protein S6 Kinases, 70-kDa - physiology; Signal transduction; Sports Medicine; Statistics as Topic; Strength training; Young Adult; Greece; Athens Greece; Muscle hypertrophy; Protein translation; Resistance training; Skeletal muscle
• ISSN: 1439-6319; 1439-6327; 1439-6327
• DOI: 10.1007/s00421-007-0564-y

The purpose of the present study was to investigate the possible relationship between a change in Thr 389 phosphorylation of p70S6 kinase (p70 S6k ) after a single resistance training session and an increase in skeletal muscle mass following short-term resistance training. Eight male subjects performed an initial resistance training session in leg press, six sets of 6RM with 2 min between sets. Muscle biopsies were obtained from the vastus lateralis before (T1) and 30 min after the initial training session (T2). Six of these subjects completed a 14-week resistance-training programme, three times per week (nine exercises, six sets, 6RM). A third muscle biopsy was obtained at the end of the 14-week training period (T3). One repetition maximum (1RM) squat, bench press and leg press strength as well as fat-free mass (FFM, with dual energy X-ray absorptiometry) were determined at T1 and T3. The results show that the increase in Thr 389 phosphorylation of p70 S6k after the initial training session was closely correlated with the percentage increase in whole body FFM ( r  = 0.89, P  < 0.01), FFM leg ( r  = 0.81, P  < 0.05), 1RM squat ( r  = 0.84, P  < 0.05), and type IIA muscle fibre cross sectional area ( r  = 0.82, P  < 0.05) after 14 weeks of resistance training. These results may suggest that p70 S6k phosphorylation is involved in the signalling events leading to an increase in protein accretion in human skeletal muscle following resistance training, at least during the initial training period.