Paul M. Gordon

Cognitive behavioral stress management effects on injury and illness among competitive athletes: A randomized clinical trial

Cognitive behavioral stress management (CBSM) has previously been found to reduce fatigue, depression, and cortisol response to heavy exercise training among competitive collegiate athletes and to speed physical and psychological recovery from surgery (1,2). Our study assessed the efficacy of a CBSM program to reduce the frequency of injury and illness among collegiate athletes in a randomized, single-blind, controlled clinical trial. Following assessment of baseline medical history, mood state, stress, cortisol, sleep, alcohol use, and exercise training, collegiate rowers were stratified by gender and competitive level and randomly assigned to either a control group or a CBSM group. Exercise training information and psychosocial assessments were repeated immediately following the intervention period, and health care providers who were blinded to participant assignment recorded the frequency of medical visits and the number of days injured or ill until the end of the season. Athletes randomly assigned to a CBSM group experienced significant reductions in the number of illness and injury days as compared to control group athletes. CBSM participants also had half the number of health service visits as did controls. The data suggest that a time-limited CBSM intervention designed specifically for an athlete population may be an effective prophylactic treatment to reduce the incidence of injury and illness among competitive collegiate athletes.

Resistance exercise training modulates acute gene expression during human skeletal muscle hypertrophy

We sought to determine whether acute resistance exercise (RE)-induced gene expression is modified by RE training. We studied the expression patterns of a select group of genes following an acute bout of RE in naïve and hypertrophying muscle. Thirteen untrained subjects underwent supervised RE training for 12 wk of the nondominant arm and performed an acute bout of RE 1 wk after the last bout of the training program (training+acute). The dominant arm was either unexercised (control) or subjected to the same acute exercise bout as the trained arm (acute RE). Following training, men (14.8 ± 2.8%; P < 0.05) and women (12.6 ± 2.4%; P < 0.05) underwent muscle hypertrophy with increases in dynamic strength in the trained arm (48.2 ± 5.4% and 72.1 ± 9.1%, respectively; P < 0.01). RE training resulted in attenuated anabolic signaling as reflected by a reduction in rpS6 phosphorylation following acute RE. Changes in mRNA levels of genes involved in hypertrophic growth, protein degradation, angiogenesis, and metabolism commonly expressed in both men and women was determined 4 h following acute RE. We show that RE training can modify acute RE-induced gene expression in a divergent and gene-specific manner even in genes belonging to the same ontology. Changes in gene expression following acute RE are multidimensional, and may not necessarily reflect the actual adaptive response taking place during the training process. Thus RE training can selectively modify the acute response to RE, thereby challenging the use of gene expression as a marker of exercise-induced adaptations.

INTERLEUKIN-15 AND INTERLEUKIN-15Rα SNPs AND ASSOCIATIONS WITH MUSCLE, BONE, AND PREDICTORS OF THE METABOLIC SYNDROME

The aims of this study were to examine associations between two SNPs in the human IL-15 gene and three SNPs in the IL-15Ralpha gene with predictors of metabolic syndrome and phenotypes in muscle, strength, and bone at baseline and in response to resistance training (RT). Subjects were Caucasians who had not performed RT in the previous year and consisted of a strength cohort (n=748), volumetric cohort (n=722), and serum cohort (n=544). Subjects completed 12 weeks of unilateral RT of the non-dominant arm, using their dominant arm as an untrained control. ANCOVA analyses revealed gender-specific associations with: (1) IL-15 SNP (rs1589241) and cholesterol (p=0.04), LDL (p=0.02), the homeostasis model assessment (HOMA; p=0.03), and BMI (p=0.002); (2) IL-15 SNP (rs1057972) and the pre- to post-training absolute difference in 1RM strength (p=0.02), BMI (p=0.008), and fasting glucose (p=0.03); (3) IL-15Ralpha SNP (rs2296135) and baseline total bone volume (p=0.04) and the pre- to post-training absolute difference in isometric strength (p=0.01); and 4) IL-15Ralpha SNP (rs2228059) and serum triglycerides (p=0.04), baseline whole muscle volume (p=0.04), baseline cortical bone volume (p=0.04), and baseline muscle quality (p=0.04). All associations were consistent in showing a potential involvement of the IL-15 pathway with muscle and bone phenotypes and predictors of metabolic syndrome.

PPARα L162V underlies variation in serum triglycerides and subcutaneous fat volume in young males

BackgroundOf the five sub-phenotypes defining metabolic syndrome, all are known to have strong genetic components (typically 50–80% of population variation). Studies defining genetic predispositions have typically focused on older populations with metabolic syndrome and/or type 2 diabetes. We hypothesized that the study of younger populations would mitigate many confounding variables, and allow us to better define genetic predisposition loci for metabolic syndrome.MethodsWe studied 610 young adult volunteers (average age 24 yrs) for metabolic syndrome markers, and volumetric MRI of upper arm muscle, bone, and fat pre- and post-unilateral resistance training.ResultsWe found the PPARα L162V polymorphism to be a strong determinant of serum triglyceride levels in young White males, where carriers of the V allele showed 78% increase in triglycerides relative to L homozygotes (LL = 116 ± 11 mg/dL, LV = 208 ± 30 mg/dL; p = 0.004). Men with the V allele showed lower HDL (LL = 42 ± 1 mg/dL, LV = 34 ± 2 mg/dL; p = 0.001), but women did not. Subcutaneous fat volume was higher in males carrying the V allele, however, exercise training increased fat volume of the untrained arm in V carriers, while LL genotypes significantly decreased in fat volume (LL = -1,707 ± 21 mm3, LV = 17,617 ± 58 mm3 ; p = 0.002), indicating a systemic effect of the V allele on adiposity after unilateral training. Our study suggests that the primary effect of PPARα L162V is on serum triglycerides, with downstream effects on adiposity and response to training.ConclusionOur results on association of PPARα and triglycerides in males showed a much larger effect of the V allele than previously reported in older and less healthy populations. Specifically, we showed the V allele to increase triglycerides by 78% (p = 0.004), and this single polymorphism accounted for 3.8% of all variation in serum triglycerides in males (p = 0.0037).

Resistin Polymorphisms Are Associated with Muscle, Bone, and Fat Phenotypes in White Men and Women

Objective: The biological function of resistin (RST) is unknown, although it may have roles in obesity, diabetes, and insulin resistance. The objective of this study was to examine the effects of single nucleotide polymorphisms (SNPs) in the human RST gene on muscle, bone, and adipose tissue phenotypes and in response to resistance training (RT).

Sleep Duration Predicts Cardiometabolic Risk in Obese Adolescents

OBJECTIVEnTo examine the independent contributions of objectively measured sleep duration and fragmentation on cardiometabolic risk accumulation in free-living obese adolescents.nnnSTUDY DESIGNnCharacteristics of metabolic syndrome (waist circumference, mean arterial pressure, fasting high-density lipoprotein cholesterol, triglycerides, glucose) were measured in obese adolescents and standardized residuals (z-scores) were summed (inverse high-density lipoprotein cholesterol) to create a continuous cardiometabolic risk score (cMetScore), adjusted for age, sex, and race. Sleep and physical activity were objectively measured in habitual, free-living conditions for 7 days (SenseWear Pro3, BodyMedia, Pittsburgh, Pennsylvania; n = 37; 54% female, ages 11-17 years). Associations between sleep duration and cMetScore were assessed via multiple linear regression.nnnRESULTSnBody mass index, total sleep time, and sleep session length were each correlated with cMetScore (P < .05 all). Total sleep time was inversely and independently associated with cMetScore (r = -0.535, P = .001) and was the best independent predictor of metabolic risk.nnnCONCLUSIONSnSleep duration inversely predicts cardiometabolic risk in obese adolescents, even when we controlled for various measures of physical activity, anthropometry, and adiposity. Further research should investigate the biological mechanism of this relationship and the potential treatment effect of sleep intervention in decreasing cardiometabolic risk in this population.

Strength Capacity and Cardiometabolic Risk Clustering in Adolescents

OBJECTIVES: The purpose of this study was to determine the gender-specific independent association between muscular strength and cardiometabolic risk clustering in a large cohort (n = 1421) of children. METHODS: Principal component analysis was used to determine the pattern of risk clustering and to derive a continuous aggregate score (MetScore) from various cardiometabolic risk components: percent body fat (%BF), fasting glucose, blood pressure, plasma triglycerides levels, and HDL-cholesterol. Gender-stratified risk and MetScore were assessed by using general linear models and logistic regression for differences between strength tertiles, as well as independent associations with age, BMI, estimated cardiorespiratory fitness (CRF), physical activity, and muscular strength (normalized for body mass). RESULTS: In both boys (n = 670) and girls (n = 751), there were significant differences in cardiometabolic profiles across strength tertiles, such that stronger adolescents had lower overall risk. Age, BMI, cardiorespiratory fitness, physical activity participation, and strength were all individually correlated with multiple risk components, as well as the overall MetScore. However, in the adjusted model, only BMI (β = 0.30), physical inactivity (β = 0.30), and normalized strength capacity (β = –1.5) emerged as significant (P < .05) predictors of MetScore. %BF was the strongest loading coefficient within the principal component analysis–derived MetScore outcome. CONCLUSIONS: Normalized strength is independently associated with lower cardiometabolic risk in boys and girls. Moreover, %BF was associated with all cardiometabolic risk factors and carried the strongest loading coefficient. These findings bolster the importance of early strength acquisition and healthy body composition in childhood.

The quantity and quality of physical activity among those trying to lose weight

BACKGROUNDnRegular exercise to elicit caloric expenditure is an important component for achieving weight loss. The Healthy People 2000 objectives recommend regular sustained physical activity lasting 30 minutes, five days per week (Objective 1.3) particularly for weight loss. Moreover, this recommendation has been restated for weight loss and overall health benefits in the Centers for Disease Control and Prevention / American College of Sports Medicine (CDC/ACSM) statement and Surgeon Generals Report (SGR) on Physical ActivitY and Health. Thus, we sought to identify the relative quality, and quantity of physical activity among people trying to lose weight.nnnDESIGNnCross-sectional self-reported data from the West Virginia Behavioral Risk Factor Surveillance System (BRFSS) were used. The BRFSS is a state-based telephone survey of adults that uses a multistage cluster design based on the Waksberg method of random-digit dialing. Data froM 2769 men and 4490 women were obtained from the 1992, 1994, and 1996 surveys.nnnRESULTSnHalf (49.6%) of individuals trying to lose weight did not engage in any physical activity. Further, only 15% of respondents trying to lose weight reported exercising regularly. Nevertheless, those trying to lose weight were more likely (OR [odds ratio] = 1.3; 95% CI [confidence interval], 1.14, 1.51, p < 0.001) to exercise regularly than those not trying to lose weight. In particular, women trying to lose weight were significantly more likely (OR = 1.45; 95% CI, 1.22,1.74, p < 0.001) to exercise regularly than women not trying to lose weight. Conversely, men trying to lose weight were no more likely to exercise regularly (p = .23) than men not trying to lose weight. Among respondents who were using exercise for weight loss, only 14.7% were expending > or =1000 kcal/week and 18.2% were expending > or =500 kcal/week. Weekly expenditure rates of > or =1000 kcal/week were more likely to occur among men (17%) than women (13.8%), in younger age groups, and among those with higher educational attainment.nnnCONCLUSIONnThese data suggest that while certain individuals trying to lose weight are more likely to engage in regular physical activity, most persons trying to lose weight have not adopted regular physical activity as part of their weight loss practice. These results suggest that public health efforts to effectively integrate physical activity into weight control practices of West Virginians have been minimally successful.

Allometric scaling of isometric biceps strength in adult females and the effect of body mass index

The purposes of this study were to (1) derive and test allometric scaling models of biceps isometric strength using body mass (BM) and muscle cross-sectional area (CSA) as the scaling variables, (2) assess the influence of body mass index (BMI) by separating the cohort by BMI (normal <25xa0kg/m2 vs. overweight/obese ≥25xa0kg/m2) and repeating step 1, and (3) assess the effect of BMI on isometric strength allometrically adjusted for differences in CSA by comparing scaled strength between normal weight versus overweight/obese women. The participants were 183 women (18–39xa0years old) who reported no strength training in the prior year. Isometric strength and CSA of the biceps were assessed on the non-dominant arm. The CSA allometric model met all statistical criteria and produced a scaling exponent of 0.44. The BM model did not meet these criteria until the entire cohort was separated by BMI. The scaling exponents for normal weight and overweight/obese women were 1.48 and 0.35, respectively. These data suggest that BMI exerted an influence on the relationship between BM and allometrically scaled isometric strength and may be explained by previous studies demonstrating greater contribution of fat mass (FM) versus fat-free mass (FFM) to BMI in overweight/obese women. As such, allometric scaling models of isometric strength, especially in populations that are heterogeneous with regard to body composition, must be carefully tested and examined across the range of BMI. Isometric strength relative to CSA was not significantly different between groups. However, allometrically scaled strength, using CSA as the criterion variable, was significantly greater in overweight/obese women compared to those of normal weight. These data suggest that isometric strength in women is not completely determined by CSA and other factors such as intramuscular fat and muscle fiber type may be confounding or contributing factors.

Environmental Perceptions Related to Physical Activity in High- and Low-Risk Counties:

To identify whether perceptions about the physical activity environment were related to the prevalence of sedentary lifestyle, residents from high-risk (n = 153) or low-risk (n = 100) counties were interviewed. County risk status was determined by the prevalence of cardiovascular mortality, overweight, and sedentary lifestyle. Key public officials in the same counties were also interviewed. Residents in the low-risk county were more likely to report having sidewalks in their community and that these sidewalks were safe and well lit than residents living in the high-risk counties. Low-risk county residents also reported more indoor recreation facilities being available than the residents in the high-risk counties. Residents supported allocating tax dollars toward improving sidewalks, lighting, and so on. Thus a more conducive environment for physical activity was found in the low-risk county. Improving physical environments and individual perceptions could help increase physical activity behavior.