Biomedical subjects

Linda M LeMura

Publications and source records attributed to Linda M LeMura.

5 recordsLinked to original sources

PubMed2006

The effect of physical activity and physical fitness on plasma adiponectin in adults with predisposition to metabolic syndrome.

The purpose of this study was to measure changes in plasma adiponectin (ApN) over 24 months of exercise intervention in middle age adults with a predisposition to metabolic syndrome and to determine if changes in ApN were more affected by physical activity or physical fitness. Thirty-six subjects completed a 24 months home-based exercise program (cycling>or=three times per week, >or=45 min/session at 50-65% of VO2peak). Body composition, blood samples, and physical fitness were studied at baseline and after 12 and 24 months of participation in the study. The prescribed physical activity was monitored via self-reported exercise diary to determine MET levels, hours, and exercise compliance. Two-tailed repeated measures ANOVA and Spearman Rank Correlation Coefficients were used to detect significant differences and associations between the variables. ApN increased significantly (P<0.05) after 12 months in males (n=17; 5.3+/-1.9-7.0+/-3.0 microg ml-1) but not in females (n=9; 8.6+/-3.8-11.5+/-4.0 microg ml-1). The net change in ApN over 24 months was significantly correlated to the net change in VO2peak (physical fitness) (r=0.66; P<0.001), whereas exercise intensity was negatively correlated to DeltaApN over 12 months (r=-0.4; P<or=0.04) and 24 months (r=-0.45; P<or=0.02). Based on our results, an improvement in cardiorespiratory fitness of 15% increased plasma ApN concentration. Our findings suggest that moderate physical activity performed over many months induces positive changes in the plasma ApN concentration in adults with a predisposition to metabolic syndrome.

Adiponectin↗

PubMed2004

Quantitative analysis of single- vs. multiple-set programs in resistance training.

The purpose of this study was to examine the existing research on single-set vs. multiple-set resistance training programs. Using the meta-analytic approach, we included studies that met the following criteria in our analysis: (a) at least 6 subjects per group; (b) subject groups consisting of single-set vs. multiple-set resistance training programs; (c) pretest and posttest strength measures; (d) training programs of 6 weeks or more; (e) apparently "healthy" individuals free from orthopedic limitations; and (f) published studies in English-language journals only. Sixteen studies generated 103 effect sizes (ESs) based on a total of 621 subjects, ranging in age from 15-71 years. Across all designs, intervention strategies, and categories, the pretest to posttest ES in muscular strength was (chi = 1.4 +/- 1.4; 95% confidence interval, 0.41-3.8; p < 0.001). The results of 2 x 2 analysis of variance revealed simple main effects for age, training status (trained vs. untrained), and research design (p < 0.001). No significant main effects were found for sex, program duration, and set end point. Significant interactions were found for training status and program duration (6-16 weeks vs. 17-40 weeks) and number of sets performed (single vs. multiple). The data indicated that trained individuals performing multiple sets generated significantly greater increases in strength (p < 0.001). For programs with an extended duration, multiple sets were superior to single sets (p < 0.05). This quantitative review indicates that single-set programs for an initial short training period in untrained individuals result in similar strength gains as multiple-set programs. However, as progression occurs and higher gains are desired, multiple-set programs are more effective.

Adolescent↗

PubMed2002

The effects of frequency of encouragement on performance during maximal exercise testing.

The aim of this study was to determine the effects of frequency of verbal encouragement during maximal exercise testing. Twenty-eight participants (12 males, 16 females) aged 20.9 +/- 1.5 years (mean +/- s) performed a maximal exercise test (VO2max) on a treadmill without any verbal encouragement. The participants were matched according to their pre-test VO2max and placed into either a control group or one of three experimental groups. They performed a second exercise test (post-test) 1 week later. During the second test, the control group received no verbal encouragement; the 20 s (20E), 60 s (60E) and 180 s (180E) encouragement groups received verbal encouragement every 20, 60 and 180 s, respectively, beginning with stage 3 of the exercise test. Relative VO2max, exercise time, blood lactate concentration, respiratory exchange ratio (RER) and ratings of perceived exertion (RPE) were not significantly different from the first test to the second test for the control group without verbal encouragement and the 180E group that received infrequent encouragement. Post-test values were significantly higher than pre-test values for the 20E and 60E groups. The post-test values of the 20E group were significantly higher than their pre-test values for relative VO2max (P < 0.001), exercise time (P < 0.0001), blood lactate concentration (P < 0.05), RER (P < 0.01) and RPE (P < 0.0001); this was also the case for the 60E group for relative VO2max (P < 0.01), blood lactate concentration (P < 0.05), RER (P < 0.05) and RPE (P < 0.05). The results suggest that frequent verbal encouragement (every 20 s and 60 s in the present study) leads to significantly greater maximum effort in a treadmill test than when no encouragement is given or when the encouragement is infrequent (i.e. every 180 s).

Achievement↗

PubMed2002

Factors that alter body fat, body mass, and fat-free mass in pediatric obesity.

PURPOSE: The purpose of this study was to quantify the effects of exercise treatment programs on changes in body mass, fat-free mass, and body fat in obese children and adolescents. METHODS: By using the meta-analytic approach, studies that met the following criteria were included in our analyses: 1) at least six subjects per group; 2) subject groups consisting of children in the 5- to 17-yr age range; 3) pretest and posttest values for either body mass, percent body fat, or fat-free mass (FFM); 4) used exercise as a mode of treatment (e.g., walking, jogging, cycle ergometry, high-repetition resistance exercise, and combinations); 6) training programs >or= 3 wk; 7) full-length publications (not conference proceedings); 8) apparently "healthy" children (i.e., free from endocrine diseases and disorders); and 9) published studies in English language journals only. RESULTS: A total of 120 investigations were located that addressed the issue of exercise as a method of treatment in pediatric obesity. Of those, 30 met our criteria for inclusion. Across all designs and categories, fixed-effects modeling yielded significant decreases in the following dependent variables: 1) percent body fat (mean = 0.70 +/- 0.35; 95% CI = 0.21 to 1.1); 2) FFM (mean = 0.50 +/- 0.38; 95% CI = 0.03 to 0.57); 3) body mass (mean = 0.34 +/- 0.18; 95% CI = 0.01 to 0.46); 4) BMI (mean = 0.76 +/- 0.55; 95% CI = 4.24 to 1.7), and 5) VO2max (mean = 0.52 +/- 0.16; 95% CI = 0.18 to 0.89), respectively. Significant differences were found as a function of the type intervention groups (exercise vs exercise + behavioral modification; P < 0.04); body composition assessment methods (skinfold vs hydrostatic weighing, DEXA, and total body water; P < 0.006); exercise intensity (60-65%, vs >or= 71% VO2max; P < 0.01); duration ( 30 min; P < 0.03); and mode (aerobic vs aerobic + resistance training; P < 0.02). Stepwise linear regression suggested that initial body fat levels (or body mass), type of treatment intervention, exercise intensity, and exercise mode accounted for most of the variance associated with changes in body composition after training. CONCLUSIONS: Exercise is efficacious for reducing selected body composition variables in children and adolescents. The most favorable alterations in body composition occurred with 1) low-intensity, long-duration exercise; 2) aerobic exercise combined with high-repetition resistance training; and 3) exercise programs combined with a behavioral-modification component.

Adolescent↗

PubMed2002

Effects of fixed ratio schedules of reinforcement on exercise by college students.

Response-contingent reinforcement was expected to increase the time spent riding a stationary exercise cycle by college women. A single-subject experimental design was used. Three college-age women rode a stationary cycle until they were either too tired to continue or until 45 minutes elapsed. Video clips were used to reinforce cycling in the first part of the experiment. Under some conditions, no video clips were presented (baseline). In other conditions, the video was on for the entire session or 25 sec. of video was presented after the completion of FR 40 (40 rotations of the cycle's pedals) or 80 (80 rotations of the cycle's pedals) schedules. In the second part of the experiment, money was presented following every 20 (FR 20) or 40 (FR 40) rotations of the cycle's pedals. The time spent riding the cycle increased over the baseline when video clips were presented. No consistent differences were observed when the video clips were on for the entire session and when they were presented under FR 40 and FR 80 schedules. For one out of two participants, monetary reward increased the time spent riding the cycle. The data suggest that reinforcement schedules are a means of initiating and maintaining adherence to an exercise program.

Adult↗