James S Skinner

Indiana University Bloomington | IUB · Department of Kinesiology

This study aimed to assess if, during incremental exercise, considering individual characteristics can make the relationship between the percentages of heart rate (HRR) and oxygen uptake (VO2R) reserve either 1:1 or more accurate. Cycle ergometer data of the maximal incremental exercise tests performed by 450 healthy and sedentary participants (17-...

The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implicati...

Background The percentages of heart rate (%HRR) or oxygen uptake (%V̇O 2 R) reserve are used interchangeably for prescribing aerobic exercise intensity due to their assumed 1:1 relationship, although its validity is debated. This study aimed to assess if %HRR and %V̇O 2 R show a 1:1 relationship during steady-state exercise (SSE) and if exercise in...

Exercise prescription is complex and can vary greatly. As well, methods have their own advantages and disadvantages. The purpose of this discussion is to consider if some of these methods should be modified. We look at the concept of the heart rate and oxygen intake reserve because it is recommended by the American College of Sports Medicine.

Background: Body composition is known to differ across metabolic health and weight phenotypes. Regular exercise improves body composition, yet little is known about differences in exercise response across metabolic health and weight phenotypes. Methods: Normal weight (n=376) and overweight/obese (OWOB) adults (n=456) from the HERITAGE Family Study...

Objectives We investigated whether high responsiveness or low responsiveness to exercise training aggregates in the same individuals across seven cardiometabolic traits. Methods A total of 564 adults (29.2% black, 53.7% female) from the HERITAGE family study completed a 20-week endurance training programme (at 55%–75% of participants’ maximal oxyg...

Introduction: According to current guidelines, the intensity of health-enhancing aerobic exercise should be prescribed using a percentage of heart rate reserve (%HRR), which is considered to be more closely associated (showing a 1:1 relation) with the percentage of oxygen uptake reserve (%V[Combining Dot Above]O2R) rather than with the percentage...

There is evidence from human twin and family studies as well as mouse and rat selection experiments that there are considerable interindividual differences in the response of cardiorespiratory fitness (CRF) and other cardiometabolic traits to a given exercise programme dose. We developed this consensus statement on exercise response variability fol...

We investigated the associations between steroid hormones and resting and exercise blood pressure in the sedentary state and in response to an exercise program controlling for sex, body mass, ethnicity, age, oral contraceptives, hormone therapy, smoking and alcohol intake in subjects from the HERITAGE Family Study. In the sedentary state, 267 men (...

Background/objectives: Plasma steroid hormone levels vary between men and women, but their associations with BMI and adiposity are controversial. Furthermore, little is known about the role of exercise programs on the relationship between steroid hormones and adiposity. This report evaluates these relationships for plasma levels of adrenal, gonada...

Background and aims: GlycA is a relatively new biomarker for inflammation as well as cardiometabolic disease risk. However, the effect of exercise on GlycA is largely unknown. Therefore, the purpose of this study was to examine the effects of regular exercise on the inflammatory marker GlycA across seven studies and 14 exercise interventions. Met...

PROCEEDINGS

Objective Identify determinants of plasma adropin concentrations, a secreted peptide translated from the Energy Homeostasis Associated (ENHO) gene linked to metabolic control and vascular function. Methods Associations between plasma adropin concentrations, demographics (sex, age, BMI) and circulating biomarkers of lipid and glucose metabolism wer...

The aim of this report is to evaluate the relationships between baseline levels of adrenal, gonadal and conjugated steroids and baseline cardiorespiratory fitness, as assessed by maximal oxygen uptake (VO2max), as well as its response to a standardized exercise program. To address this aim we used a subset of the HERITAGE Family Study (N = 448). In...

Objective: Our goal was to examine the effects of regular endurance exercise on plasma GlycA levels, a novel NMR-derived biomarker of systemic inflammation. Methods: We examined NMR-derived plasma GlycA levels before and after 5-6 months of exercise training in 1,194 adults from four studies: APOE (N=104), DREW (N=298), GERS (N=78), HERITAGE (N=714...

Objective: The goal was to examine lipoprotein subclass responses to regular exercise as measured in 10 exercise interventions derived from six cohorts. Methods: Nuclear magnetic resonance spectroscopy was used to quantify average particle size, total and subclass concentrations of very low-density lipoprotein, low-density lipoprotein, and high-de...

Reduced strength, balance, and functional independence diminish quality of life and increase healthcare costs. Sixty adults (82.2±4.9 yrs) were randomized to control or three 12-week intervention groups: bioDensity (bD); Power Plate (PP) whole-body vibration (WBV); or bD+PP. bD involved one weekly 5-sec maximal contraction of four muscle groups. PP...

OBJECTIVE: The goal was to examine lipoprotein subclass responses to regular exercise as measured in 10 exercise interventions derived from six cohorts. We hypothesized that regular exercise has beneficial effects on the overall lipoprotein subclass profile in previously sedentary adults. METHODS: NMR spectroscopy (LipoScience Inc., Raleigh, NC) wa...

Given the controversy around HDL-C as a therapeutic target, there is a need to investigate other features of HDL and how they respond to various preventive interventions. We tested the hypothesis that regular exercise would have beneficial effects on HDL particle (HDL-P) traits in sedentary adults. Methods: The following HDL-P traits were measured...

The purpose of this study was to examine how well two commonly used age-based prediction equations for maximal heart rate (HRmax ) estimate the actual HRmax measured in Black and White adults from the HERITAGE Family Study. A total of 762 sedentary subjects (39% Black, 57% Females) from HERITAGE were included. HRmax was measured during maximal exer...

Individuals differ in the response to regular exercise. Whether there are people who experience adverse changes in cardiovascular and diabetes risk factors has never been addressed. An adverse response is defined as an exercise-induced change that worsens a risk factor beyond measurement error and expected day-to-day variation. Sixty subjects were...

Detailed description of the six studies and the background material used to determine the technical error for fasting insulin. (DOCX)

The purpose of this Position Stand is to provide an overview of issues critical to understanding the importance of exercise and physical activity in older adult populations. The Position Stand is divided into three sections: Section 1 briefly reviews the structural and functional changes that characterize normal human aging, Section 2 considers the...

Contributions of the DNA sequence variation at the endothelin 1 locus to the risk of hypertension and to endurance training-induced changes in blood pressure were investigated in the Aerobics Center Longitudinal Study and the Health, Risk Factors, Exercise Training and Genetics Family Study cohorts. We identified 586 normotensive control subjects a...

The purpose of this study was to identify regions of the human genome linked to submaximal exercise heart rates in the sedentary state and in response to a standardized 20-wk endurance training program in blacks and whites of the HERITAGE Family Study. A total of 701 polymorphic markers covering the 22 autosomes were used in the genome-wide linkage...

Associations between cholesteryl ester transfer protein (CETP) polymorphisms and high-density lipoprotein cholesterol (HDL-c) levels before and after 20 wk of endurance training were investigated in the HERITAGE Family Study. Plasma HDL-c, HDL(2)-c, HDL(3)-c, and apolipoprotein (apo)A1 levels were measured, and 13 CETP single nucleotide polymorphis...

The expression of the four and a half LIM domains 1 gene (FHL1) is increased in the muscle of individuals who show an improvement in insulin sensitivity index (S(I)) after 20 weeks of exercise training. The aim of the present study was to investigate associations between three FHL1 single nucleotide polymorphisms (SNPs) and variables derived from a...

We tested the hypothesis that peroxisome proliferator-activated receptor-delta (PPARdelta) gene polymorphisms are associated with cardiorespiratory fitness and plasma lipid responses to endurance training. Associations between the PPARdelta exon 4 +15 C/T and exon 7 +65 A/G polymorphisms and maximal exercise capacity and plasma lipid responses to 2...

Low levels of cardiorespiratory fitness are associated with high risk of mortality, and improvements in fitness are associated with reduced mortality risk. However, a poor understanding of the physical activity-fitness dose response relation remains. To examine the effect of 50%, 100%, and 150% of the NIH Consensus Development Panel recommended phy...

Oxidant stress and overproduction of reactive oxygen species (ROS) contribute to the development of cardiovascular disease. Oxidative modifications of low-density lipoproteins (LDL) are thought to play an early and critical role in atherogenesis. LDL oxidation can be reproduced in vitro, but results usually show a large interindividual variation no...

This study investigated different methods of scaling submaximal cardiac output (Q) and stroke volume (SV) to best normalize for body size (body surface area [BSA], height [Ht], weight [Wt], and fat-free mass [FFM]). Q and SV were measured at both an absolute (50 W) and a relative power output (60 % of VO2max) in 337 men and 422 women, 17 to 65 year...

We investigated whether regular aerobic exercise could affect plasma total homocysteine (tHcy), and whether there were sex-related or racial differences in tHcy changes. Data were available for 816 black and white men and women, aged 17-65 years, 711 of whom completed a 20 week aerobic exercise training program. The tHcy concentration was measured...

C-reactive protein (CRP) is a sensitive marker of systemic low-grade inflammation. Increased plasma levels of CRP predict the risk of cardiovascular and metabolic diseases. Although genetic factors account for 30-40% of individual differences in plasma CRP levels, genomic regions contributing to CRP levels remain unknown. We performed a genome-wide...

Although the health benefits of exercise for individuals with Persian Gulf War veterans illnesses (GWVI) are documented, many of these individuals do not exercise regularly enough to obtain benefits. The purpose of this study was to investigate factors predicting exercise compliance among individuals with GWVI in a multicenter, randomized, clinical...

To determine whether a common quantitative trait locus (QTL) influences the variation of fasting triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels, we used a bivariate multipoint linkage analysis with 654 polymorphic markers in 99 white and 101 black families. The phenotypes were investigated under two conditions: at baselin...

Pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-alpha), stimulate the release of C-reactive protein (CRP). We investigated the association between the TNF-alpha G-308A polymorphism and plasma CRP levels. Subjects were 456 White (225 men, 231 women) and 232 Black (83 men, 149 women) healthy adults who underwent a 20-week standar...

Motivated by strong correlations between plasma levels of triglycerides (TG) and adiposity traits, we conducted a series of bivariate genome-wide linkage analyses of TG with body mass index (BMI), total fat mass (FAT), percentage of body fat (FATPC), and abdominal subcutaneous fat (ASF). Maximum lod scores of 3.3, 3.0, 2.2 and 2.4, respectively, we...

Evidence of a genetic component for resting heart rate (RHR) has been found. Quantitative trait loci (QTLs) for baseline RHR have been reported, but not for RHR training response. It is of interest to identify QTLs that may harbor genes influencing RHR variation at baseline and in response to regular exercise training. Here, a multipoint variance c...

The Agouti-related protein (AGRP), an appetite modulator, induces hyperphagia when administered intracerebroventricularly or when overexpressed in transgenic mice. Exogenous administration of AGRP in rodents predisposes to high fat and high sugar intakes. The objective was to examine the potential associations of 2 ethnic-specific polymorphisms in...

Learning Objective: To describe the poorly understood conditions of chronic fatigue syndrome and fibromyalgia and their treatments, as well as to discuss how exercise may exacerbate or ameliorate the symptoms associated with these disorders, the types of information needed to prescribe exercise, and what changes might be expected.

Fasting triglyceride (TG) levels in total plasma and in lipoprotein subfractions were assessed both at baseline and after a 20-week exercise training intervention in 99 White and 101 Black families. A genome-wide multipoint variance component linkage analysis was performed separately by race, using 509 markers. The strongest evidence of linkage was...

This study assessed major gene effects for baseline HDL-C, LDL-C, TG, and their training responses (post-training minus baseline) in 527 individuals from 99 White families and 326 individuals from 113 Black families in the HERITAGE Family Study. The baseline phenotypes were adjusted for the effects of age and BMI, and the training response phenotyp...

We investigated the associations between the hepatic lipase gene (LIPC) -514C>T polymorphism and lipases, lipoproteins, and insulin sensitivity (Si) responses to exercise training. Hepatic lipase and lipoprotein lipase activities, plasma lipoprotein levels, and Si were measured in the sedentary state and post-exercise training in the Health, Risk F...

Impaired insulin secretion, insulin action, insulin-independent glucose effectiveness, glucose tolerance and the associated abnormalities in insulin and glucose metabolism phenotypes are precursors of type 2 diabetes. Genome-wide multipoint variance component linkage scans were carried out using 654 markers to identify quantitative trait loci for i...

Protein tyrosine phosphatase 1B (PTPN1) affects the regulation of insulin signaling and energy metabolism. We studied whether polymorphisms in the PTPN1 gene impact body fat distribution in the HERITAGE Family Study cohort in 502 white and 276 black subjects. Insulin sensitivity index, glucose disappearance index, acute insulin response to glucose...

Despite the well known genetic component influencing plasma lipid-lipoprotein levels and the observed correlations among these traits, little is known about pleiotropic heritable determinants among them. Our aim is to investigate pair-wise polygenic and environmental correlations among lipid-lipoprotein levels at baseline and in response to regular...

Genome-wide multipoint linkage analyses were performed to identify chromosomal regions harboring genes influencing LDL-cholesterol, total apolipoprotein B (apoB), and LDL-apoB levels using 654 markers. They were assessed in a sedentary state (baseline) and after a 20 week endurance training program. Strong evidence for two quantitative trait loci (...

Adiponectin is an adipocytokine with lowered blood levels in obesity and Type 2 diabetes mellitus. We sought to define the specific effects of different alleles of the gene encoding adiponectin. We studied the associations of adiponectin gene sequence variations with body fat distribution and insulin indices in 503 White and 276 Black subjects of t...

To determine the effect of a 20-week endurance training program in healthy, previously sedentary participants on measures derived from an intravenous glucose tolerance test (i.v.GTT). An i.v.GTT was performed before and after a standardized training program in 316 women and 280 men (173 blacks and 423 whites). Participants exercised on cycle ergome...

This study explores sex and race differences in the association between changes in fat mass (FM), abdominal visceral fat (AVF), and abdominal subcutaneous fat (ASF) on blood lipid changes consequent to aerobic exercise training. The sample included 613 participants (428 white and 185 black, 46% men) from the HERITAGE Family Study. Total FM was dete...

The purpose of this research was to investigate the effects of apriori estrogen replacement therapy (ERT) and endurance exercise training in postmenopausal women on abdominal visceral fat (AFV) and other selected variables related to body composition and the metabolic syndrome (MS). Forty-eight healthy and previously sedentary postmenopausal women...

To determine if the relationship between abdominal visceral fat (AVF) and measures of adiposity are different between Black and White subjects and to develop valid field prediction models that accurately identify those individuals with AVF levels associated with high risk for chronic disease. Cross-sectional measurements obtained from 91 Black men,...

Calcium (Ca(2+)) intake may play a role in the regulation of body weight. Increased Ca(2+) intake has been associated with lower body weight, BMI, and adiposity measures in cross-sectional studies. We examined the association between Ca(2+) intake, derived from the Willett FFQ, and overall and abdominal adiposity in Black and White men and women of...