title: Intramuscular anabolic signaling and endocrine response following high volume and high intensity resistance exercise protocols in trained men.
abstract: Resistance exercise paradigms are often divided into high volume (HV) or high intensity (HI) protocols, however, it is unknown whether these protocols differentially stimulate mTORC1 signaling. The purpose of this study was to examine mTORC1 signaling in conjunction with circulating hormone concentrations following a typical HV and HI lower-body resistance exercise protocol. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) performed each resistance exercise protocol in a random, counterbalanced order. Blood samples were obtained at baseline (BL), immediately (IP), 30 min (30P), 1 h (1H), 2 h (2H), and 5 h (5H) postexercise. Fine needle muscle biopsies were completed at BL, 1H, and 5H. Electromyography of the vastus lateralis was also recorded during each protocol. HV and HI produced a similar magnitude of muscle activation across sets. Myoglobin and lactate dehydrogenase concentrations were significantly greater following HI compared to HV (P = 0.01-0.02), whereas the lactate response was significantly higher following HV compared to HI (P = 0.003). The growth hormone, cortisol, and insulin responses were significantly greater following HV compared to HI (P = 0.0001-0.04). No significant differences between protocols were observed for the IGF-1 or testosterone response. Intramuscular anabolic signaling analysis revealed a significantly greater (P = 0.03) phosphorylation of IGF-1 receptor at 1H following HV compared to HI. Phosphorylation status of all other signaling proteins including mTOR, p70S6k, and RPS6 were not significantly different between trials. Despite significant differences in markers of muscle damage and the endocrine response following HV and HI, both protocols appeared to elicit similar mTORC1 activation in resistance-trained men.
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Gonzalez
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA jay.hoffman@ucf.edu.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Hoffman
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Townsend
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Jajtner
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Carleigh H
authors.initials: CH
authors.lastname: Boone
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Kyle S
authors.initials: KS
authors.lastname: Beyer
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Kayla M
authors.initials: KM
authors.lastname: Baker
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Wells
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Mangine
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Robinson
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: Church
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, Florida, USA.
authors.forename: Leonardo P
authors.initials: LP
authors.lastname: Oliveira
authors.affiliation: Exercise and Biochemical Nutrition Laboratory, Baylor University, Waco, Texas, USA.
authors.forename: Darryn S
authors.initials: DS
authors.lastname: Willoughby
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Fukuda
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, Florida, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Stout
keywords: Hormone hypothesis; intensity; mTOR pathway; mTORC1; volume