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Muscle growth resistance exercise

Scott J Dankel, Kevin T Mattocks, Matthew B Jessee, Samuel L Buckner, J Grant Mouser, Brittany R Counts, Gilberto C Laurentino, Jeremy P Loenneke
The principle of progressive overload must be adhered to for individuals to continually increase muscle size with resistance training. While the majority of trained individuals adhere to this principle by increasing the number of sets performed per exercise session, this does not appear to be an effective method for increasing muscle size once a given threshold is surpassed. Opposite the numerous studies examining differences in training loads and sets of exercise performed, a few studies have assessed the importance of training frequency with respect to muscle growth, none of which have tested very high frequencies of training (e...
October 17, 2016: Sports Medicine
Samuel L Buckner, Scott J Dankel, Kevin T Mattocks, Matthew B Jessee, J Grant Mouser, Brittany R Counts, Jeremy P Loenneke
In this paper we revisit a topic originally discussed in 1955, namely the lack of direct evidence that muscle hypertrophy from exercise plays an important role in increasing strength. To this day, long-term adaptations in strength are thought to be primarily contingent on changes in muscle size. Given this assumption, there has been considerable attention placed on programs designed to allow for maximization of both muscle size and strength. However, the conclusion that a change in muscle size affects a change in strength is surprisingly based on little evidence...
October 7, 2016: Muscle & Nerve
Mathew J Wong, Crystal Kantores, Julijana Ivanovska, Amish Jain, Robert P Jankov
Chronic neonatal pulmonary hypertension (PHT) frequently results in early death. Systemically administered Rho-kinase (ROCK) inhibitors prevent and reverse chronic PHT in neonatal rats, but at the cost of severe adverse effects, including systemic hypotension and growth restriction. Simvastatin has pleiotropic inhibitory effects on isoprenoid intermediates that may limit activity of RhoA, which signals upstream of ROCK. We therefore hypothesized that statin treatment would safely limit pulmonary vascular RhoA activity and prevent and reverse experimental chronic neonatal PHT via downstream inhibitory effects on pathological ROCK activity...
September 30, 2016: American Journal of Physiology. Lung Cellular and Molecular Physiology
Kevin A Murach, R Grace Walton, Christopher S Fry, Sami L Michaelis, Jason S Groshong, Brian S Finlin, Philip A Kern, Charlotte A Peterson
This investigation evaluated whether moderate-intensity cycle ergometer training affects satellite cell and molecular responses to acute maximal concentric/eccentric resistance exercise in middle-aged women. Baseline and 72 h postresistance exercise vastus lateralis biopsies were obtained from seven healthy middle-aged women (56 ± 5 years, BMI 26 ± 1, VO2max 27 ± 4) before and after 12 weeks of cycle training. Myosin heavy chain (MyHC) I- and II-associated satellite cell density and cross-sectional area was determined via immunohistochemistry...
September 2016: Physiological Reports
Ellie M Carrell, Aundrea R Coppola, Helen J McBride, Robert T Dirksen
Orai1 is a transmembrane protein that forms homomeric, calcium-selective channels activated by stromal interaction molecule 1 (STIM1) after depletion of intracellular calcium stores. In adult skeletal muscle, depletion of sarcoplasmic reticulum calcium activates STIM1/Orai1-dependent store-operated calcium entry. Here, we used constitutive and inducible muscle-specific Orai1 knockout (KO) mice to determine the acute and long-term developmental effects of Orai1 ablation on muscle structure and function. Skeletal muscles from constitutive, muscle-specific Orai1 KO mice exhibited normal postnatal growth and fiber type differentiation...
September 1, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Simon D Burley, Jayde Whittingham-Dowd, Jeremy Allen, Jean-Francois Grosset, Gladys L Onambele-Pearson
Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol)...
2016: PloS One
Willian das Neves, Christiano Robles Rodrigues Alves, Ney Robson de Almeida, Fátima Lúcia Rodrigues Guimarães, Paulo Rizzo Ramires, Patricia Chakur Brum, Antonio Herbert Lancha
AIMS: Resistance exercise training (RET) has been adopted as non-pharmacological anti-catabolic strategy. However, the role of RET to counteract cancer cachexia is still speculative. This study aimed to verify whether short-term RET would counteract skeletal muscle wasting in a severe cancer cachexia rat model. MAIN METHODS: Wistar rats were randomly allocated into four experimental groups; 1) untrained control rats (control), 2) rats submitted to RET (control+RET), 3) untrained rats injected with Walker 256 tumor cells in the bone marrow (tumor) and 4) rats injected with Walker 256 tumor cells in the bone marrow and submitted to RET (tumor+RET)...
October 15, 2016: Life Sciences
Scott J Dankel, Samuel L Buckner, Matthew B Jessee, Kevin T Mattocks, J Grant Mouser, Brittany R Counts, Gilberto C Laurentino, Takashi Abe, Jeremy P Loenneke
PURPOSE: Applying blood flow restriction during low-load resistance training has been shown to augment muscle hypertrophy which has been attributed to metabolic accumulation. It remains unknown, however, whether metabolites can augment muscle growth when maintained post-exercise. METHODS: Thirteen untrained individuals (6 males and 7 females) performed 24 training sessions. The control arm performed one set of elbow flexion (70 % 1RM) to volitional fatigue, while the experimental arm performed the same protocol immediately followed by 3 min of blood flow restriction (70 % arterial occlusion)...
October 2016: European Journal of Applied Physiology
Neil A Schwarz, Sarah K McKinley-Barnard, Mike B Spillane, Thomas L Andre, Joshua J Gann, Darryn S Willoughby
The purpose of this study was to investigate the acute messenger (mRNA) expression of the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) isoforms, insulin-like growth factor-1Ea (IGF-1Ea), and myostatin in response to 2 resistance exercise intensities. In a uniform-balanced, crossover design, 10 participants performed 2 separate testing sessions involving a lower body resistance exercise component consisting of a lower intensity (50% of 1-repetition maximum; 1RM) protocol and a higher intensity (80% of 1RM) protocol of equal volumes...
August 2016: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Andrew J Galpin, Andrew C Fry, Justin X Nicoll, Christopher A Moore, Brian K Schilling, Donald B Thomason
Extracellular signal-regulated protein kinase 1/2 (ERK1/2) moderates skeletal muscle growth; however, chronic responses of this protein to unique resistance exercise (RE) paradigms are yet to be explored. The purpose of this investigation was to describe the long-term response of ERK1/2 following circuit weight training (CWT), recreationally weight training (WT), powerlifting (PL) and weightlifting (WL). Independent t-tests were used to determine differences in trained groups compared to sedentary controls...
July 2016: Research in Sports Medicine
Mark W Hamrick, Meghan E McGee-Lawrence, Danielle M Frechette
Skeletal muscle and bone share common embryological origins from mesodermal cell populations and also display common growth trajectories early in life. Moreover, muscle and bone are both mechanoresponsive tissues, and the mass and strength of both tissues decline with age. The decline in muscle and bone strength that occurs with aging is accompanied in both cases by an accumulation of adipose tissue. In bone, adipocyte (AC) accumulation occurs in the marrow cavities of long bones and is known to increase with estrogen deficiency, mechanical unloading, and exposure to glucocorticoids...
2016: Frontiers in Endocrinology
Francesco Giallauria, Antonio Cittadini, Neil Andrew Smart, Carlo Vigorito
Aging is inexorably accompanied by a progressive decline of muscle mass, quality and strength. The resulting condition has been termed sarcopenia. Age-related sarcopenia can be accelerated by a variety of factors including changes in the hormonal milieu, inactivity, poor nutrition, chronic illness, and loss of integrity and function in the peripheral and central nervous systems. The downstream mechanisms by which these risk factors cause sarcopenia are not completely understood. Exercise training (particularly resistance training) has long been identified as the most promising method for increasing muscle mass and strength among older people...
2016: Monaldi Archives for Chest Disease, Archivio Monaldi Per le Malattie del Torace
Joseph A M J L Janssen
Physical exercise may be vital to the maintenance of the endocrine system with aging and its helps to restore loss of activity of the endocrine system with aging. There is evidence that physical exercise induces activity of the growth hormone-insulin-like growth factor-1 axis and so produces anabolic effects in skeletal muscles. Mechano growth factor (MGF), a locally produced isoform of IGF-1, has been hypothesized to be important for the maintenance of skeletal muscles with aging. Short-term high-resistance exercise results in an increase of MGF mRNA in young but not in elderly subjects...
2016: Frontiers of Hormone Research
Matthew H Sharp, Ryan P Lowery, C Brooks Mobley, Carlton D Fox, Eduardo O de Souza, Kevin A Shields, James C Healy, Ned Q Arick, Richard M Thompson, Michael D Roberts, Jacob M Wilson
OBJECTIVE: The purpose of this study was to investigate the effects of Fortetropin on skeletal muscle growth and strength in resistance-trained individuals and to investigate the anabolic and catabolic signaling effects using human and rodent models. METHODS: In the rodent model, male Wistar rats (250 g) were gavage fed with either 1.2 ml of tap water control (CTL) or 0.26 g Fortetropin for 8 days. Then rats participated in a unilateral plantarflexion exercise bout...
June 22, 2016: Journal of the American College of Nutrition
David D Church, Neil A Schwarz, Mike B Spillane, Sarah K McKinley-Barnard, Tom L Andre, Alejandro J Ramirez, Darryn S Willoughby
OBJECTIVE: Ursolic acid administration following resistance exercise increases mammalian target of rapamycin complex 1 (mTORC1) activity and skeletal muscle IGF-1 concentration in murines in a manner similar to l-leucine yet remains unexamined in humans. This study examined serum and skeletal muscle insulin-like growth factor-1 (IGF-1) and Akt/mTORC1 signaling activity following ingestion of either ursolic acid or l-leucine immediately after resistance exercise. METHODS: Nine resistance-trained men performed 3 lower-body resistance exercise sessions involving 4 sets of 8-10 repetitions at 75%-80% one repetition maximum (1-RM) on the angled leg press and knee extension exercises...
June 22, 2016: Journal of the American College of Nutrition
Brittany R Counts, Samuel L Buckner, Scott J Dankel, Matthew B Jessee, Kevin T Mattocks, J Grant Mouser, Gilberto C Laurentino, Jeremy P Loenneke
The purpose of the study was to remove the influence of an external load and determine if muscle growth can be elicited by maximally contracting through a full range of motion. In addition, the acute physiologic and perceptual responses to each stimulus were also investigated. Thirteen participants completed 18 sessions of unilateral elbow flexion exercise. Each arm was designated to either NO LOAD or HIGH LOAD condition (70% one repetition maximum). For the NO LOAD condition, participants repeatedly contracted as hard as they could through a full range of motion without the use of an external load...
October 1, 2016: Physiology & Behavior
Juha P Ahtiainen, Juha J Hulmi, Maarit Lehti, William J Kraemer, Kai Nyman, Harri Selänne, Markku Alen, Jyrki Komulainen, Vuokko Kovanen, Antti A Mero, Anastassios Philippou, Eija K Laakkonen, Keijo Häkkinen
Insulin-like growth factor-I (IGF-I) and its splice variants Insulin-like growth factor-I isoform Ea (IGF-IEa) and mechano growth factor (MGF) may play an important role in muscular adaptations to resistance training (RT) that may be modulated by ageing. It has been suggested that IGF-I induces cellular responses via AKT8 virus oncogene cellular homolog (Akt) and Extracellular signal-regulated kinase (Erk) signalling pathways. Therefore, resistance exercise-induced changes in skeletal muscle IGF-IEa and MGF messenger ribonucleic acid (mRNA), and MGF, Erk1/2, Akt and p70S6K protein expression were investigated before and after 21 weeks of RT in younger (YM, 20-34 yrs...
November 2016: European Journal of Sport Science
Amy E Knapp, Daniel Goldberg, Hamid Delavar, Breanna M Trisko, Kechun Tang, Michael C Hogan, Peter D Wagner, Ellen C Breen
A single bout of exhaustive exercise signals expression of vascular endothelial growth factor (VEGF) in the exercising muscle. Previous studies have reported that mice with life-long deletion of skeletal myofiber VEGF have fewer capillaries and a severe reduction in endurance exercise. However, in adult mice, VEGF gene deletion conditionally targeted to skeletal myofibers limits exercise capacity without evidence of capillary regression. To explain this, we hypothesized that adult skeletal myofiber VEGF acutely regulates skeletal muscle perfusion during muscle contraction...
July 1, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Dariush Sheikholeslami-Vatani, Slahadin Ahmadi, Rashad Salavati
BACKGROUND: Exercise order affects repetition performance and acute hormonal responses to resistance training (RT) programs. OBJECTIVES: The purpose of this study was to compare the acute effects of two different resistance exercise orders (REO) on number of repetitions and serum Insulin-like Growth Factor-1 (IGF-1), testosterone and cortisol levels in normal-weight and obese men. MATERIALS AND METHODS: 25 untrained college-aged men were assigned to either obese (n = 11) or normal-weight (n = 15) groups...
March 2016: Asian Journal of Sports Medicine
Hayao Ozaki, Tomoharu Kitada, Takashi Nakagata, Hisashi Naito
AIM: Here, we aimed to compare the effect of a combination of body mass-based resistance exercise and moderate-intensity (55% peak oxygen uptake [ V˙O2 peak]) walking or high-intensity (75% V˙O2 peak) walking on muscle size and V˙O2 peak in untrained older women. METHODS: A total of 12 untrained older women (mean age 60 ± 2 years) were randomly assigned to either a moderate-intensity aerobic training group (n = 6) or high-intensity aerobic training group (n = 6)...
May 23, 2016: Geriatrics & Gerontology International
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