Muscle and liver glycogen utilization during prolonged lift and carry exercise: male and female responses.

This study examined the use of carbohydrates by men and women during lift/carry exercise. Effects of menstrual cycle variation were examined in women. Twenty-five subjects (15 M, 10 F) were studied; age 25 ± 2y M, 26 ± 3y F, weight 85 ± 3 kg* M, 63 ± 3 kg F, and height 181 ± 2 cm* M, 161 ± 2 cm F (*  < 0.

Glucocorticoid Receptor (NR3C1) Variants Associate with the Muscle Strength and Size Response to Resistance Training.

Glucocorticoid receptor (NR3C1) polymorphisms associate with obesity, muscle strength, and cortisol sensitivity. We examined associations among four NR3C1 polymorphisms and the muscle response to resistance training (RT). European-American adults (n = 602, 23.

Leptin and leptin receptor genetic variants associate with habitual physical activity and the arm body composition response to resistance training.

Purpose: We investigated the influence of Leptin (LEP) and leptin receptor (LEPR) SNPs on habitual physical activity (PA) and body composition response to a unilateral, upper body resistance training (RT) program.

Methods: European-derived American volunteers (men=111, women=131, 23.4 ± 5.

The effect of specimen temperature on the polymerization of a resin-composite.

Objective: To use rapid scan FT-IR and Knoop microhardness to determine the effect of specimen temperature on the rate and extent of polymerization of a dental resin.

Methods: Two-millimeter thick specimens of shade A2 Tetric EvoCeram were light cured for 20s at 22, 26, 30, and 35°C. The IR spectrum was obtained at the bottom of the specimens at a rate of 3 measurements per second for the first 5 min, and then again 2h later.

AKT1 polymorphisms are associated with risk for metabolic syndrome.

Converging lines of evidence suggest that AKT1 is a major mediator of the responses to insulin,insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. We hypothesized that AKT1 variants may play a role in the endophenotypes that makeup metabolic syndrome.

Vascular remodeling in response to 12 wk of upper arm unilateral resistance training.

Unlabelled: Participation in regular aerobic exercise has been shown to increase arterial size and that exercise-induced vascular remodeling may be regional rather than systemic. However, these issues have been minimally investigated concerning resistance training.

Purposes: To determine whether 1) resistance training of the nondominant arm elicits an increase in diameter of the brachial artery and 2) unilateral training induces arterial remodeling in the contralateral arm.

Association of age with muscle size and strength before and after short-term resistance training in young adults.

The purpose of this study was to assess the association of age with muscle mass and strength in a group of young adults before and after 12 weeks of progressive resistance training. Eight hundred twenty-six young males and females (age 24.34 +/- 5.

CNTF 1357 G -> A polymorphism and the muscle strength response to resistance training.

The present study examined associations between the ciliary neurotrophic factor (CNTF) 1357 G --> A polymorphism and the muscle strength response to a unilateral, upper arm resistance-training (RT) program among healthy, young adults. Subjects were 754 Caucasian men (40%) and women (60%) who were genotyped and performed a training program of the nondominant (trained) arm with the dominant (untrained) arm as a comparison. Peak elbow flexor strength was measured with one repetition maximum, isometric strength with maximum voluntary contraction, and bicep cross-sectional area with MRI in the trained and untrained arms before and after training.

Myostatin and follistatin polymorphisms interact with muscle phenotypes and ethnicity.

Purpose: We examined associations among myostatin (MSTN) 2379 A > G and 163 G > A and follistatin (FST) -5003 A > T and -833 G > T single nucleotide polymorphisms (SNP) on the muscle size and the strength response to resistance training (RT).

Methods: Subjects (n = 645, age = 24.1 +/- 0.

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 <25 kg/m(2) vs. overweight/obese > or =25 kg/m(2)) 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 (18-39 years old) who reported no strength training in the prior year.

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

Background: Of 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.

Subcutaneous fat alterations resulting from an upper-body resistance training program.

Purpose: It is believed spot reduction, the exercise-induced localized loss of subcutaneous fat, does not occur as a result of an exercise program; however, evidence as a whole has been inconsistent. To reexamine this concept, we compared subcutaneous fat measurements before and after resistance training among 104 subjects (45 men, 59 women).

Methods: Subjects participated in 12 wk of supervised resistance training of their nondominant arm.

Allometric scaling of biceps strength before and after resistance training in men.

Purpose: The purposes of this study were 1) derive allometric scaling models of isometric biceps muscle strength using pretraining body mass (BM) and muscle cross-sectional area (CSA) as scaling variables in adult males, 2) test model appropriateness using regression diagnostics, and 3) cross-validate the models before and after 12 wk of resistance training.

Methods: A subset of FAMuSS (Functional SNP Associated with Muscle Size and Strength) study data (N=136) were randomly split into two groups (A and B). Allometric scaling models using pretraining BM and CSA were derived and tested for group A.

The muscle strength and size response to upper arm, unilateral resistance training among adults who are overweight and obese.

Overweight and obesity result in musculoskeletal impairments that limit exercise capacity. We examined if the muscle strength and size response to resistance training (RT) differed among 687 young (mean +/- SEM, 24.2 +/- 0.

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).

Research Methods And Procedures: Subjects were white and consisted of strength (n = 482) and size (n = 409) cohorts who had not performed RT in the previous year.

Postexercise muscle glycogen recovery enhanced with a carbohydrate-protein supplement.

Purpose: This study assessed whether liquid carbohydrate-protein (C+P) supplements, ingested early during recovery, enhance muscle glycogen resynthesis versus isoenergetic liquid carbohydrate (CHO) supplements, given early or an isoenergetic solid meal given later during recovery (PLB).

Methods: Two hours after breakfast (7.0 kcal.

ACE ID genotype and the muscle strength and size response to unilateral resistance training.

Purpose: To examine associations among the angiotensin I-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and the response to a 12-wk (2 d.wk) unilateral, upper-arm resistance training (RT) program in the trained (T, nondominant) and untrained (UT, dominant) arms.

Methods: Subjects were 631 (mean+/-SEM, 24.

Examination of extrinsic foot muscles during running using mfMRI and EMG.

Over-pronation has been cited as a key contributor to many types of running injuries. However, the roles of the extrinsic foot muscles during running have not been adequately identified. The purpose of this study was to examine the muscle functional (mf) MRI and EMG responses to perturbations of the foot by running in varus, neutral and valgus wedged shoes.

Variability in muscle size and strength gain after unilateral resistance training.

Purpose: This study assessed variability in muscle size and strength changes in a large cohort of men and women after a unilateral resistance training program in the elbow flexors. A secondary purpose was to assess sex differences in size and strength changes after training.

Methods: Five hundred eighty-five subjects (342 women, 243 men) were tested at one of eight study centers.

ACTN3 genotype is associated with increases in muscle strength in response to resistance training in women.

The alpha-actinin 3 (ACTN3) gene encodes a protein of the Z disk of myofibers, and a polymorphism of ACTN3 results in complete loss of the protein. The ACTN3 genotype (R577X) has been found to be associated with performance in Australian elite athletes (Yang N, MacArthur DG, Gulbin JP, Hahn AG, Beggs AH, Easteal S, and North K. Am J Hum Genet 73: 627-631, 2003).

Regulation of net hepatic glycogenolysis and gluconeogenesis during exercise: impact of type 1 diabetes.

The effects of type 1 diabetes on the contributions of net hepatic glycogenolysis and gluconeogenesis to glucose production (GP) at rest and during moderate (MOD) and high (HI) intensity running were examined in healthy control (n = 6) and type 1 diabetic (n = 5) subjects matched for age, weight, and maximum aerobic capacity by combined noninvasive measurements of hepatic glycogen content using (13)C nuclear magnetic resonance spectroscopy and determination of GP using [6,6-(2)H(2)]glucose. In the control subjects, GP increased in proportion to the intensity of the exercise [at rest (REST), 14.3 +/- 0.

Effects of repeated creatine supplementation on muscle, plasma, and urine creatine levels.

The purpose of this case study was to examine the effects of repeated creatine administration on muscle phosphocreatine, plasma creatine, and urine creatine. One male subject (age, 32 years; body mass, 78.4 kg; height, 160 cm; resistance training experience, 15 years) ingested creatine (20 g.

Comparison of MRI with EMG to study muscle activity associated with dynamic plantar flexion.

This study compared magnetic resonance imaging (MRI) and surface electromyography (EMG) to evaluate the effect of knee angle upon plantar flexion activity in the triceps surae muscles [medial & lateral gastrocnemius (MG, LG) and the soleus (SOL)]. Two weight & height matched groups performed identical protocols, twelve (6M, 6F) in the MRI group, twelve (8M, 4F) in the EMG group. Subjects plantar flexed dynamically for 2 min at 25% of 1-repetition maximum voluntary contraction (1-RM).

Smoking impairs muscle recovery from exercise.

Cigarette smoking is a leading cause of many adverse health consequences. Chronic nicotine exposure leads to insulin resistance and may increase the risk of developing non-insulin-dependent diabetes mellitus in young otherwise healthy smokers. To evaluate smoking-induced effects on carbohydrate metabolism, we studied muscle glycogen recovery from exercise in a young healthy population of smokers.

Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement.

In the present study, we tested the hypothesis that a carbohydrate-protein (CHO-Pro) supplement would be more effective in the replenishment of muscle glycogen after exercise compared with a carbohydrate supplement of equal carbohydrate content (LCHO) or caloric equivalency (HCHO). After 2.5 +/- 0.