The purpose of this study was to test the effect of acute thermal hypohydration on the muscle endurance performance of three groups of differentially trained subjects. Group I consisted of six anaerobically trained athletes, Group II consisted of five aerobically trained athletes, and Group III consisted of six sedentary individuals. Experimental trials involved maximal leg extensions performed on a Cybex II dynamometer under conditions of euhydration and hypohydration of minus 3% body weight. Integrated electromyographic data were also collected during each trial to factor out motivation as a variable. The maximum number of leg extension repetitions performed at or above 50% of each subject's peak torque output were compared between treatments and among the three groups. A 2 x 3 factorial analysis of variance (ANOVA) showed a significant decrease in muscle endurance when comparing euhydration to hypohydration among the anaerobically trained subjects as well as among the sedentary subjects (P less than 0.05). The aerobically trained subjects showed no significant decline in muscle endurance when comparing performance under both experimental conditions. It was hypothesized that the training adaptations that occur with aerobic conditioning and are primarily associated with increased plasma volume may be the key to explaining these results.
An improved method is described which makes possible the determination of 0.01 p.p.m. of heptachlor and heptachlor epoxide in soil with satisfactory accuracy. Soil from plots treated with 0.25, 0.50, 1, and 2 pounds per acre of heptachlor was analyzed 3 and 5l/, months after treatment. A second group of samples was taken after 8 months from an area which was treated with two different granular formulations. A third group of samples was taken in a treated area where biological control was incomplete, in an attempt to correlate chemical and biological data. The initial loss of insecticide from the soil appears to be rapid, and is followed by a much slower loss and conversion of a portion of heptachlor to heptachlor epoxide.ECENT WORK in this laboratory R demonstrated a need for a method to determine quantitatively heptachlor and heptachlor epoxide residues as low as 0.01 p.p.m. in soil. Since this is be-
Literature Cited(1) Davidow, Bernard, Radomsk;, J. L., J . Pharmacol. Exptl. Therap. 107 (3), 259-65 (1953).
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