Rachel Yeater

Effects of Resistance vs. Aerobic Training Combined With an 800 Calorie Liquid Diet on Lean Body Mass and Resting Metabolic Rate

OBJECTIVE Utilization of very-low-calorie diets (VLCD) for weight loss results in loss of lean body weight (LBW) and a decrease in resting metabolic rate (RMR). The addition of aerobic exercise does not prevent this. The purpose of this study was to examine the effect of intensive, high volume resistance training combined with a VLCD on these parameters. METHODS Twenty subjects (17 women, three men), mean age 38 years, were randomly assigned to either standard treatment control plus diet (C+D), n = 10, or resistance exercise plus diet (R+D), n = 10. Both groups consumed 800 kcal/day liquid formula diets for 12 weeks. The C+D group exercised 1 hour four times/week by walking, biking or stair climbing. The R+D group performed resistance training 3 days/week at 10 stations increasing from two sets of 8 to 15 repetitions to four sets of 8 to 15 repetitions by 12 weeks. Groups were similar at baseline with respect to weight, body composition, aerobic capacity, and resting metabolic rate. RESULTS Maximum oxygen consumption (Max VO2) increased significantly (p<0.05) but equally in both groups. Body weight decreased significantly more (p<0.01) in C+D than R+D. The C+D group lost a significant (p<0.05) amount of LBW (51 to 47 kg). No decrease in LBW was observed in R+D. In addition, R+D had an increase (p<0.05) in RMR O2 ml/kg/min (2.6 to 3.1). The 24 hour RMR decreased (p<0.05) in the C+D group. CONCLUSION The addition of an intensive, high volume resistance training program resulted in preservation of LBW and RMR during weight loss with a VLCD.

Effects of an exercise intervention using Dance Dance Revolution on endothelial function and other risk factors in overweight children.

OBJECTIVE To determine whether an exercise intervention using an active video game (Dance Dance Revolution [DDR]) is effective in improving endothelial dysfunction (EDF) and other risk factors in overweight children. DESIGN Thirty-five children (Body mass index > or = 85(th) percentile, mean age 10.21+/-1.67 years, 17 females) with EDF were assessed for flow-mediated dilation (FMD), lipids, insulin, glucose, NO(2)+NO(3), asymmetric dimethylarginine, symmetric dimethylarginine, l-arginine, height, weight, aerobic fitness, and blood pressure. In a subsample, tumor necrosis factor alpha, interleukin-6, C-reactive protein, and adiponectin were also assessed. Subjects were randomly assigned to 12-weeks of aerobic exercise (EX) using DDR or to a non-exercising delayed-treatment control group (DTC). RESULTS EX had significant improvements in FMD ( 5.56+/-5.04% compared with 0.263+/-4.54%, p=0.008), exercise time on the graded exercise test (53.59+/-91.54 compared with -12.83+/-68.10 seconds, p=0.025), mean arterial pressure (MAP) (-5.62+/-7.03 compared with -1.44+/-2.16 mmHg, p=0.05), weight (0.91+/-1.53 compared with 2.43+/-1.80 kg, p=0.017) and peak VO(2) (2.38+/-3.91 compared with -1.23+/-3.18 mg/kg/min, p=0.005) compared with the DTC. Thirteen EX subjects achieved normal EDF while ten did not. These groups differed at baseline with regard to total cholesterol (TC) and low-density lipoprotein (LDL). CONCLUSION Twelve weeks of DDR-use improved FMD, aerobic fitness, and MAP in overweight children. Improvements occurred without changes in inflammatory markers or nitric oxide production. The results document the need to explore relationships between obesity, endothelial function, inflammation, lipids, exercise intensity, and gender in a larger sample of overweight children.

The effects of exercise intensity on body composition, weight loss, and dietary composition in women

OBJECTIVE There is controversy over whether exercise and/or exercise intensity has an effect on total caloric intake or diet composition. The purpose of this study was to test the effect of exercise intensity without dietary manipulation on body composition and/or weight loss and to determine whether exercise intensity affected total caloric intake or diet composition in normal weight young women. METHODS Fifteen women aged 18 to 34 years with a maximal oxygen consumption average or below on the Palo Alto norms served as subjects. Subjects were randomly assigned to: 1) low heart rate intensity exercise group (LI, N = 7) which exercised 40 to 45 minutes approximately four times weekly at a mean heart rate of 132 beats per minute (bpm); 2) high heart rate intensity group (HI, N = 8) which exercised 40 to 45 minutes approximately four times weekly at a mean HR of 163 bpm. All subjects were given a maximal exercise test prior to and during weeks eight, 12 and 16. The first 4 weeks served as a control period, followed by approximately 11 weeks of exercise. Each subject recorded her dietary intake for 1 complete week, including a weekend, during weeks 2, 6, 10 and 14 of the study. RESULTS VO2 max increased (p < .05) in HI (29 +/- 6 ml/kg/minute to 38 +/- 7) but did not change in LI (36 +/- 5 to 38 +/- 7). Percent fat decreased in HI (p < .05) (27 +/- 7 to 22 +/- 4) but was unchanged in LI (22 +/- 6 to 21 +/- 6). The weekly intake of total kcal, carbohydrate, protein and fat did change significantly for either group. The weekly intake of saturated fat declined significantly (p < .05) in HI (21.2 +/- 5.8 g to 14.9 +/- 5.5 g); their weekly intake of cholesterol also decreased (p < .05) between months 2 to 3 (249 +/- 109 mg to 159 +/- 58 mg). No other differences in dietary intake between groups were found. CONCLUSION High heart rate intensity exercise training without dietary manipulation resulted in a decrease in body fat, but not weight change, as well as a decrease in the intake of saturated fat and cholesterol in normal weight young women. These changes were not observed after low heart rate intensity training.

Tethered swimming forces in the crawl, breast and back strokes and their relationship to competitive performance

Abstract Forces developed during fully tethered swimming by 18 male athletes were measured uding a load call in the tether cable. Three competitive strokes were studied: crawl, breast and back. Arm and leg components of the crawl and breast stroke were observed separately. Attempts were made to correlate peak and mean tether forces with competitive velocities. A positive correlation was observed between mean tether force and velocity in the crawl, particularly among distance specialists. A negative correlation was found between crawl velocity and the peak/mean force ratio. The data also suggest that the kick contributes significant force in both the crawl and breaststroke. In neither case, however, does the whole stroke produce as much force as the sum of the arm and leg components would indicate.

Combined effects of aerobic exercise and omega-3 fatty acids in hyperlipidemic persons

Because both aerobic exercise and fish oil ingestion have been shown to decrease plasma lipids, we examined the effects of combining these modalities in hyperlipidemic subjects. Thirty-four subjects were randomly assigned to one of four groups as follows: fish oil and exercise (FE), N = 7, 50 ml of oil daily and 3 d.wk-1 of aerobic exercise; fish oil (F), N = 7, 50 ml of oil daily; corn oil (CN), N = 10, 50 ml of oil daily; and control (C), N = 10. Blood samples were drawn at baseline and at the end of 4, 8, and 12 wk. The FE and F groups showed significantly lower triglycerides with respect to treatment as compared to the CN and C groups. The FE, F, and CN groups exhibited lower total cholesterol values than the control group but were not different from each other. HDL cholesterol was significantly increased after treatment in the FE and F groups as compared to the CN and C groups. Serum apo-B, LDL cholesterol, and LDL protein decreased significantly in the FE group but not the F group from baseline to 12 wk. VO2max increased and percent fat decreased only in the FE group. In conclusion, aerobic exercise improved the effects of fish oil on LDL cholesterol and apo-B and improved fitness and body composition in hyperlipidemic subjects.

RESISTANCE TRAINING EXERCISE AND CREATINE IN PATIENTS WITH CHARCOT-MARIE-TOOTH DISEASE

Resistance exercise and creatine supplementation independently improve strength and function in patients with certain neuromuscular diseases. The purpose of this study was to examine the effects of resistance training with and without creatine supplementation on muscle, strength, and function in patients with Charcot–Marie–Tooth (CMT) disease. Twenty patients with CMT consumed 5 g/day creatine or placebo while participating in resistance training for 12 weeks. Energy metabolites, muscle fiber type and size, strength, and timed activities of daily living were measured before and after training. There were no differences between creatine or placebo groups for any outcome. For the groups combined, exercise training increased type I muscle fiber diameter (48.2 ± 14.2 μm vs. 55.4 ± 14.8 μm), strength, and activities of daily living (ADL) times. Thus, patients respond to resistance training with muscle fiber adaptations, and improvements in strength and function. Creatine was not beneficial.

A simple analytical model for the crawl stroke

Abstract A simple analytical model for the crawl stroke is described. The swimmer is modelled as a torso with arms rotating like paddle wheels; for simplicity the kick is ignored. Starting with theoretical and experimental estimates for drag coefficents and anatomical data from a male collegiate swimming team, the model was adjusted to fit certain tethered and free swimming data. Its behavior was then compared to that of real swimmers in five different experimental situations and good general agreement was observed. The model was found to require much lower drag forces than are measured experimentally, however, perhaps because the kick was not considered. The model provides insight into several aspects of swimming research, including the relationship between tethered swimming forces and actual propulsive forces during free swimming.

Physical activity and condition, dietary habits, and serum lipids in second-year medical students.

Level of physical activity has been found to be an independent risk factor for coronary heart disease. Because lifestyle and dietary habits are frequently established by early adulthood, we examined the physical activity, physical fitness, body composition, plasma lipids, and diets of a group of second-year medical students. Medical students were studied because of the presumption that they were knowledgeable about exercise and appropriate diet and would have future influence on their patients. A questionnaire which assessed physical activity was returned by 69 (89%) of the 80 students. Over 50% reported no hard or very hard physical activity either during the week or on weekends. Three subjects were smokers. Body composition, cardiovascular fitness, and plasma lipids were assessed in 20 subjects selected at random from the 69. Five of the 15 men, but none of the five women, had greater-than-desirable body fat. Cardiovascular fitness was at least average compared to normal values, but three had hypertension at rest and 12 had hypertensive responses to exercise. Seven of the men had LDL cholesterol above 130 mg/dl and three had LDL:HDL ratios greater than 3. There was a positive correlation (r = 0.5, p = 0.02) between hard/very hard activity assessed by questionnaire and VO2max and a negative correlation (r = 0.4, p = 0.05) between VO2max and percent fat. All 20 subjects reported above average to severe amounts of stress. Analysis of a 48-hr diet record of 22 students showed an average consumption of 47% carbohydrates, 17% protein, and 36% fat. The polyunsaturated/saturated ratio was 0.43.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of exercise and creatine on myosin heavy chain isoform composition in patients with Charcot–Marie–Tooth disease

It is not known whether myosin heavy chain (MHC) content changes in response to exercise training or creatine supplementation in subjects with Charcot–Marie–Tooth disease (CMT). Based on previous data, we hypothesized that resistance exercise and creatine would increase the percentage of type I MHC composition in the vastus lateralis muscle and that myosin isoform changes would correlate with improved chair rise‐time in CMT subjects. To test this hypothesis, 18 CMT subjects were randomly assigned to either a placebo or creatine group. All subjects performed a 12‐week, home‐based, moderate‐intensity resistance training program. Chair rise‐time was measured before and after the training program. Muscle biopsies were obtained from the vastus lateralis before and after the 12‐week program. Gel electrophoresis showed a significant decrease (∼30%) in MHC type I in CMT subjects given creatine supplementation when compared with placebo. There was a nonsignificant increase in both MHC type IIa (∼23%) and MHC type IIx (∼7%) in CMT subjects given creatine. Reduced MHC type I content and increased MHC type IIa content correlated with faster chair rise‐times (i.e., improved muscle performance). The training‐induced change in MHC IIa content was inversely correlated with chair rise‐time in CMT subjects given creatine. When the two subject groups were combined, there was a linear, negative relationship between the change in MHC type IIa content and chair rise‐time after training and a positive relationship between the training‐induced change in MHC type I content and chair rise‐time. These data suggest that improved function (chair rise‐time) was associated with a lower level of MHC type I and increased MHC type IIa composition. Furthermore, the data are consistent with the hypothesis that creatine supplementation alters MHC composition in CMT patients undergoing resistance training and that MHC changes associated with creatine supplementation can improve muscle function. Muscle Nerve, 2006

The Effect of Exercise on Peripheral Muscle in Emphysema: A Preliminary Investigation

Emphysema has been associated with loss of aerobic muscle fibers and decreased blood supply. However, when these changes begin and whether exercise can prevent these changes is unknown. The purpose of this study was to examine peripheral muscle at different time points during the development of emphysema and to determine the additional effects of muscle activity. In a series of 3 experiments, emphysema was induced in hamsters. Exercise was simulated through surgical overload (OV) of the plantaris muscle of one leg. Animals were sacrificed at 1, 3, and 5 months following emphysema induction. Fiber type composition and capillary-to-fiber ratio (CFR) were determined. There were no significant changes in fiber type composition in the 1-month group. A significant increase in type IIA fiber composition (mean 72.0 vs. 54.5%) and decrease in type IIB fiber (mean 13.3 vs. 28.1%) was seen in the non-overloaded muscles following 3 months. In the 5-month group, there was a significant decrease in percentage of type I fibers (mean 14.7 vs. 28.0%). There were no significant differences in fiber type composition in the OV limb, regardless of duration. The CFR was significantly lower in the OV limb after 5-months of emphysema (mean 0.92 vs. 1.55 cap/fiber). Muscle overload prevented emphysema-associated changes in fiber type composition, but not in CFR. Peripheral muscle is affected early in the course of emphysema and chronic overload may play an important role in preserving normal muscle composition.