Ben R. Londeree

Effect of training on lactate/ventilatory thresholds: a meta-analysis.

The purpose of the investigation was to determine the effect of exercise training intensity on the lactate and ventilatory thresholds in sedentary and in active subjects using meta-analysis procedures. The original analyses included 85 study groups from 34 studies. The dependent variable was oxygen consumption at the specified threshold, and the independent variables were training intensity (control and four intensities ranging from below threshold to near maximum) and fitness level (sedentary and conditioned). Data were analyzed statistically using methods described by Hedges and Olkin (13). The results showed that sedentary subjects (effect size (ES) = 2.32) improved significantly over controls (ES = 0.15), while conditioned subjects (ES = 0.63) showed nonsignificant gains. There were no significant differences among training intensities within the fitness categories (Sed ES = 1.6 - 3.1; Cond ES = 0.3 - 1.1) although the conditioned subjects tended to respond better to high intensity training (ES of 1.1 vs 0.4). It was concluded that training at an intensity near the lactate or ventilatory threshold is an adequate training stimulus for improving the thresholds for sedentary subjects, but a higher intensity may be necessary for conditioned subjects. Detraining will reduce lactate and ventilatory thresholds.

Effect of Age and Other Factors on Maximal Heart Rate

Abstract In an attempt to reduce the confusion regarding reported effects of age upon maximal exercise heart rate (HR max), a comprehensive review of the English literature was conducted to obtain descriptive statistical data representing over 23,000 independent subjects from 5 to 81 years old. The data were split randomly into two data sets for independent regression analyses. HR max was the dependent variable while independent variables include: age, age2, age3, age4, sex, level of fitness, type of ergometer, exercise protocol, continent of residence, and race. After cross validation the data were pooled and reanalyzed. Additional validation was accomplished on identifiable subsets of the data, e.g., cross sectional, longitudinal, training, comparative ergometry, and comparative sex studies. Results identified negative linear and non-linear age factors, an ergometry factor, a fitness factor and a continent factor. Age accounted for about 70–75% of the variability. Generalized equations were proposed. Ev...

Bone density in postmenopausal women: high impact vs low impact exercise.

This 1 year study examined the effect of high impact and low impact activities on bone mineral density (BMD) at the lumbar vertebrae (L2-L4) in healthy, sedentary, early postmenopausal women. Fifteen subjects whose postmenopausal status was verified by the blood levels of follicle stimulating hormone (FSH) and estradiol were chosen. These subjects were tested on the following variables: BMD via dual photon absorptiometry, heart rate response to the Balke treadmill test, percent fat via skinfolds, and a 3-d dietary analysis. Subjects were matched and then assigned randomly to one of three groups: (a) a control nonexercising group, (b) a low impact exercise group, and (c) a high impact exercise group. The control nonexercising group experienced a significant linear decrease in BMD during the study (F = 12.63, P = 0.002). Both the low and high impact exercise groups maintained BMD during the study (F = 0.04, P = 0.85; F = 1.08, P = 0.31, respectively). The difference in BMD between the low impact and the high impact exercise groups was not significant (F = 0.36, P = 0.55). In conclusion, 20 min of moderate intensity low impact or high impact exercise 3 d.wk-1 for 1 yr is effective in maintaining BMD in early postmenopausal women.

Physiological parameters related to distance running performance in female athletes

The purpose of this study was to investigate the relationship between running pace for the 5 km, the 10 km, and the 16.09 km (10 mile) distances and the following variables: oxygen uptake and treadmill speed at predetermined lactate accumulation points (2.0 and 4.0 mmol.l-1), oxygen uptake (running economy) at three submaximal standardized treadmill speeds (196, 215, and 241 m.min-1), and maximal oxygen uptake. Thirteen moderately to highly conditioned (VO2max = 59.7 +/- 5.3 ml.kg-1.min-1; VO2 at 2.0 mmol.l-1 of plasma lactate = 46.6 +/- 4.1 ml.kg-1.min-1) female runners between the ages of 18 and 33 yr volunteered to participate. All subjects performed the laboratory tests and the 5 km, 10 km, and 16.09 km competitive time trials on an outdoor 5 km course. The correlation coefficients (r) between each race pace and maximal oxygen uptake (VO2max), speed (s) at 2.0 mmol.l-1 plasma lactate accumulation (PLA2s), and speed at 4.0 mmol.l-1 plasma lactate accumulation (PLA4s) ranged between 0.84 and 0.94. The oxygen costs of running at each of the three submaximal paces were correlated moderately with each race pace (r = -0.40 to -0.63). Hierarchal stepwise multiple regression analyses produced equations with two independent variables which explained 94 to 97% of the variability in race performance.

Maximal steady state versus state of conditioning

AbstractCriteria for the identification of maximal steady state as related to state of conditioning were evaluated. 13 volunteers walked and/or ran during a series of 15 min tests on a treadmill. The speeds ranged from mild to exhaustive. Heart rate was monitored continuously;

Comparison of blood flow in the ankle of uninjured subjects during therapeutic applications of heat, cold, and exercise.

\dot V_{O_2 }

%VO2max versus %HRmax regressions for six modes of exercise

was determined from 6 min to 9 min; and venous blood was obtained at 10 min and 15 min for lactate analyses. Max