Daniel I Ogborn

McMaster University | McMaster · Department of Medicine

An amendment to this paper has been published and can be accessed via the original article.

The purpose of this paper was to conduct a systematic review of the current body of literature and a meta-analysis to compare changes in strength and hypertrophy between low- versus high-load resistance training protocols. Searches of PubMed/MEDLINE, Cochrane Library and Scopus were conducted for studies that met the following criteria: 1) an exper...

Controversy exists as to whether different dynamic muscle actions produce divergent hypertrophic responses. The purpose of this paper was to conduct a systematic review and meta-analysis of randomized controlled trials comparing the hypertrophic effects of concentric versus eccentric training in healthy adults following regimented resistance traini...

Background A number of resistance training (RT) program variables can be manipulated to maximize muscular hypertrophy. One variable of primary interest in this regard is RT frequency. Frequency can refer to the number of resistance training sessions performed in a given period of time, as well as to the number of times a specific muscle group is tr...

OBJECTIVE: The purpose of this study was to compare activation of the upper body musculature during the barbell bench press at varying training intensities. METHODS: Twelve young, resistance-trained men performed sets of the bench press to momentary muscular failure with two different loads: a high-load (HIGH) set at 80% of 1RM and a low-load (LOW)...

The purpose of this paper was to systematically review the current literature and elucidate the effects of total weekly resistance training (RT) volume on changes in measures of muscle mass via meta-regression. The final analysis comprised 34 treatment groups from 15 studies. Outcomes for weekly sets as a continuous variable showed a significant ef...

The purpose of this study was to compare the effects of a protocol employing a combination of loading zones vs. one employing a constant medium-repetition loading zone on muscular adaptations in resistance-trained men. 19 trained men (height=176.9±7.0 cm; body mass=83.1±11.8 kg; age=23.3±2.9 years) were randomly assigned to 1 of 2 experimental grou...

Background: Human genetic disorders and transgenic mouse models have shown that mitochondrial DNA (mtDNA) mutations and telomere dysfunction instigate the aging process. Epidemiologically, exercise is associated with greater life expectancy and reduced risk of chronic diseases. While the beneficial effects of exercise are well established, the mol...

Background: It has been hypothesized that the ability to increase volume load (VL) via a progressive increase in the magnitude of load for a given exercise within a given repetition range could enhance the adaptive response to resistance training. Objectives: The purpose of this study was to compare changes in volume load (VL) over eight weeks o...

The study by Jenkins et al. attempted to elucidate the mechanisms behind the findings of Mitchell et al. (J Appl Physiol 113(1):71-77, 2012). However, we believe the work of Jenkins et al. contains methodological issues, does not meet electromyographic reporting standards, and deduces conclusions beyond which can be interpreted from the data provid...

The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength, and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were pe...

Mitochondrial dysfunction may contribute to age-associated muscle atrophy. Previous data has shown that resistance exercise (RE) increases mitochondrial gene expression and enzyme activity in older adults; however, the acute response to RE has not been well characterized. To characterize the acute mitochondrial response to unaccustomed RE, healthy...

Maximizing the hypertrophic response to resistance training (RT) is thought to be best achieved by proper manipulation of exercise program variables including exercise selection, exercise order, length of rest intervals, intensity of maximal load, and training volume. An often overlooked variable that also may impact muscle growth is repetition dur...

Older and younger men completed 12 weeks of resistance training and ingested either 500 mL of chocolate milk or placebo daily. Training increased strength in both age groups (p < 0.05), with no supplementation effect. Type I muscle fibre area increased with training (p = 0.008) with no effect of age or supplementation. Type II fibre area increased...

Endoplasmic reticulum (ER) stress results from an imbalance between the abundance of synthesized proteins and the folding capacity of the ER. In response, the unfolded protein response (UPR), attempts to restore ER function by attenuating protein synthesis and inducing chaperone expression. Resistance exercise (RE) stimulates protein synthesis; how...

EMERGING EVIDENCE SUGGESTS THAT TYPE I FIBERS DISPLAY A SUBSTANTIAL PROPENSITY FOR GROWTH IF THEY ARE SELECTIVELY TARGETED VIA LOW-LOAD TRAINING. THE PURPOSE OF THIS ARTICLE WILL BE TO REVIEW THE RESEARCH REGARDING FIBER TYPE-SPECIFIC HYPERTROPHY AND DRAW EVIDENCE-BASED CONCLUSIONS AS TO THEIR IMPLICATIONS FOR PROGRAM DESIGN. Copyright © National S...

Mitochondrial oxidative stress is a complex phenomenon that is inherently tied to energy provision and is implicated in many metabolic disorders. Exercise training increases mitochondrial oxidative capacity in skeletal muscle yet it remains unclear if oxidative stress plays a role in regulating these adaptations. We demonstrate that the chronic ele...

Table S4 Genes with at least one intragenic dmCpG site.

Table S11 Number of overlapping dmCpG sites with other studies.

Fig. S3 dmCpG sites that are common for this study and Heyn et al.

Table S1 List of differentially methylated CpG probes with age.

Table S6 Muscle-specific canonical pathway analysis.

Table S8 Correspondence of intragenic differential methylation to gene expression.

Fig. S1 Numbers of CpGs present on array in a gene and dmCpG site for same gene.

Fig. S2 Ingenuity canonical axon guidance pathway.

Table S3 ENCODE ChIP-Seq significance tool results.

Table S5 Ontology enrichment analysis.

Table S7 Differential methylation of axon guidance genes.

Table S10 List of overlapping CpG predictors of biological age with Hannum et al. study.

Table S13 Description of human subjects.

Table S14 Illumina 450 K data quality control report.

Table S2 Distribution of dmCpG.

Table S9 List of CpG sites that discriminate young from old samples.

Table S12 Description of genomic regions.

A decline in skeletal muscle mass and function with aging is well recognized, but remains poorly characterized at the molecular level. Here we report for the first time a genome-wide study of DNA methylation dynamics in skeletal muscle of healthy male individuals during normal human aging. We predominantly observed hypermethylation throughout the g...

McArdle disease (MD) is a metabolic myopathy due to myophosphorylase deficiency, which leads to a severe limitation in the rate of adenosine triphosphate (ATP) resynthesis. Compensatory flux through the myoadenylate deaminase >xanthine oxidase pathway should result in higher oxidative stress in skeletal muscle; however, oxidative stress and nuclear...

Antioxidant supplements are widely consumed by the general public; however, their effects of on exercise performance are controversial. The aim of this study was to examine the effects of an antioxidant cocktail (α-lipoic acid, vitamin E and coenzyme Q10) on exercise performance, muscle function and training adaptations in mice. C57Bl/J6 mice were...

McArdle's disease (MD) is well known as a metabolic myopathy due to myophosphorylase deficiency. We examined monocarboxylate transporters (MCT) and creatine kinase (CK) protein content in skeletal muscle from 12 patients with MD and 12 age‐matched controls, to evaluate potential cellular adaptations to compensate for the loss of glycogenolysis. MD...

Aging is associated with increased circulating interleukin-6 (IL-6) and a reduced myogenic capacity, marked by reduced muscle stem cell (satellite cell, SC) activity. Although IL-6 is an important for normal SC function, it is unclear whether elevated IL-6 associated with aging alters SC function. We hypothesized that mild chronically elevated IL-6...

McArdle disease (MD) is a metabolic myopathy due to myophosphorylase deficiency. We examined monocarboxylate transporters (MCT) and creatine kinase (CK) protein content in skeletal muscle from MD patients and age-matched controls to evaluate potential cellular adaptations that compensate for the loss of glycogenolysis. Our findings of higher MCT1 a...

Human aging is accompanied by a progressive loss of muscle mass (sarcopenia). We tested the hypothesis that older males (OMs, 70±4 yr, n=9) would have a blunted myogenic response to a physiological stimulus compared to younger controls (21±3 yr, n=9). Subjects completed an acute bout of intense unilateral muscle loading. Young healthy males matched...

The FRG1-transgenic mouse displays muscle dysfunction and atrophy reminiscent of fascioscapulohumeral muscular dystrophy (FSHD) and could provide a model to determine potential therapeutic interventions. To determine if FRG1 mice benefit from treatments that improve muscle mass and function, mice were treated with creatine alone (Cr) or in combinat...

Massage therapy is commonly used during physical rehabilitation of skeletal muscle to ameliorate pain and promote recovery from injury. Although there is evidence that massage may relieve pain in injured muscle, how massage affects cellular function remains unknown. To assess the effects of massage, we administered either massage therapy or no trea...

Muscle growth is regulated by a unique population of muscle stem cells (satellite cells: SC). Depletion or dysfunction of SC leads to a loss in muscle mass and capacity for muscle growth. It remains unknown if this cell population is adversely affected by the aging process.PURPOSE: To quantify the SC pool size and SC cell-cycle response to acute re...

Mitochondrial dysfunction has been theorized to contribute to age-associated muscle atrophy. Deficits in muscle mass are thought to be due to a degree of anabolic resistance to growth-promoting stimuli; however, it is not known whether mitochondrial dysfunction contributes to an impaired synthetic response following resistance exercise. While long-...

Mitochondrial oxidative stress is a complex phenomenon that is inherently tied to energy provision and is implicated in many metabolic disorders. Exercise training increases mitochondrial oxidative capacity in skeletal muscle yet it remains unclear if oxidative stress plays a role in regulating these adaptations. We demonstrate that the chronic ele...

A causal role for mitochondrial DNA (mtDNA) mutagenesis in mammalian aging is supported by recent studies demonstrating that the mtDNA mutator mouse, harboring a defect in the proofreading-exonuclease activity of mitochondrial polymerase gamma, exhibits accelerated aging phenotypes characteristic of human aging, systemic mitochondrial dysfunction,...

Exercise and corticotrophin‐releasing factor 2 receptor (CRF2R) agonist treatment improves skeletal muscle function, however the potential synergistic transcriptional effects of both treatments in dystrophic muscle are not characterized. Mdx (C57BL/10ScSn‐Dmdmdx) and WT (C57BL/6) mice were treated with placebo (PL) or CRF2R agonist and remained sed...

The role of mitochondrial abnormalities and mitochondrial DNA (mtDNA) mutagenesis has been extensively characterized in aging. A causal role for mtDNA mutagenesis in aging is supported by recent studies demonstrating that the polymerase gamma (PolG) mutator mouse, harbouring a proofreading‐deficient copy of PolG, exhibits an accelerated aging pheno...

Transgenic overexpression of Fascioscapulohumeral Muscular Dystrophy (FSHD) Region Gene 1 (FRG1) results in severe muscle atrophy and weakness reminiscent of the human disease FSHD. Treatments that act to mitigate muscle dysfunction in the FRG1‐transgenic mouse could hold therapeutic benefit to FSHD patients. Forty FRG1 mice were divided into seden...

A causal role for mitochondrial DNA (mtDNA) mutagenesis in the etiology of age associated cardiomyopathy is supported by the polymerase gamma (PolG) mutator mouse, harbouring a proofreading‐deficient copy of PolG, which exhibits cardiac hypertrophy, mitochondrial dysfunction in cardiomyocytes, and reduced lifespan. Longitudinal studies demonstrate...

Muscle-derived neurotrophins are thought to contribute to the adaptation of skeletal muscle to exercise, but the effects of brief exercise interventions on BDNF, NT-4/5, and trkB are not understood. RNA was extracted for RT-PCR from soleus and medial gastrocnemius of Sprague-Dawley rats exercised on a treadmill at speeds up to 20 m/min at 5% inclin...