Endurance training decreases serum testosterone levels in men without change in luteinizing hormone pulsatile release.

Cross-sectional studies have suggested that total and bioavailable testosterone levels are reduced in some male athletes. Such changes may be related to loss of body weight, increased serum cortisol, and/or alterations in LH pulsatile release. To determine how endurance training may affect androgen levels, we measured serum total testosterone, sex hormone-binding globulin, free androgen index, LH, FSH, PRL, cortisol, and weight in 15 previously sedentary males. We also examined pulsatile LH release in a subset of 5 subjects. Over 6 months of training, the men increased weekly running mileage to an average of 56 km/week. Total testosterone and free androgen index levels decreased significantly. PRL and cortisol also decreased, while single sample LH and FSH remained unchanged. There was a significant reduction in weight, which did not correlate with changes in serum testosterone levels. LH pulsatile release was not altered by training in the subset of 5 runners. These data confirm previous findings of physiological reduction in serum testosterone and PRL levels and suggest that the testosterone decrease is not related to changes in LH pulsatile release, weight, or increased serum cortisol levels.

Induction of voluntary prolonged running by rats.

The rat is widely used in studies of the metabolic and physiological effects of physical exercise. The most commonly used form of exercise is running on treadmills or mechanically driven running wheels. Rats will not voluntarily run significant distances, under normal circumstances. If rats are exposed to running wheels with food freely available, only very limited activity normally occurs. When rats with access to a running wheel are restricted to a fixed amount of food, presented once per day, consistent running occurs. The running is spontaneous and very sensitive to the amount of food provided. Six 6-wk-old rats of 197 g mean body wt were induced to run for 139 days. The distance run increased rapidly over a 20-day initial period on a food supply of 15 g/day (vs. 19.5 g/day consumption by sedentary controls). From day 20 to day 139 the mean distance run was described by the regression equation distance (m/day) = 10,410 - 37.9 X days. Food provided was varied according to distance run, ranging from 15 to 18 g/day, and was normally 17.5 g/day. Thus a food deprivation of 10% of normal consumption will result in mean distances run of approximately 8,000 m/day. The use of pair-fed control animals without access to a wheel allows the conduct of experiments to test the effects of chronic long-distance running. The running is spontaneous; thus the technique avoids the complications accompanying techniques that force running.

Prevention of myocardial disease in JCR:LA-corpulent rats by running.

The JCR:LA-corpulent rat is a congenic strain that, if homozygous for the cp gene, is obese with a very low-density lipoprotein hyperlipidemia and is insulin resistant. The male corpulent rats develop atherosclerotic lesions of the major arteries and myocardial lesions. Corpulent and lean male rats were induced through mild food restriction to run intensively (approximately 6,000 m/day) from 6 wk to 6 mo of age. Food restriction, especially when coupled with running, lowered all classes of lipids in the whole serum of corpulent rats. The principal changes in lipid concentrations were in the very low-density lipoprotein fraction. Food restriction caused a significant drop in fasting insulin levels of corpulent rats and decreased beta-cell hyperplasia. Both effects were more marked in the running animals. There was a significant decrease in myocardial lesion frequency in the food-restricted corpulent rats and an absence of lesions in the running rats. The results indicate that intensive physical activity can largely correct the lipid abnormalities and insulin resistance of this atherosclerosis-prone strain, and these changes are associated with inhibition of the disease process. However, moderate food restriction has similar effects, and the greater effects seen with intensive running may simply reflect an effectively more severe metabolic restriction in the presence of the exercise.

Suppression of food deprivation-induced high-rate wheel running in rats.

To test for involvement of endogenous opioids in the maintenance of high-rate running we have administered naloxone, a specific opioid antagonist, to rats. The animals were stabilized voluntarily running 6000 to 8000 m/day through a standard protocol and maintained in this state on approximately 18 g of food per day. Naloxone (50 mg/kg in saline) or saline alone was injected intraperitoneally on alternate days for 20 days. All rats ran less on days when naloxone was administered. The mean distance run for the group (N = 6, mean +/- SE) was: saline: 6401 +/- 985; naloxone: 5344 +/- 805 m/day. This difference was highly significant (p less than 0.001). In the 4-hour period immediately following the naloxone injection there was no inhibition of running. The second four-hour period showed a nonsignificant (p greater than 0.05) decrease in running. Inhibition of running was highly significant after eight hours (30%, p less than 0.001). The results demonstrate a clear inhibition of the high-rate running by naloxone and imply a significant role by endogenous opioids in the maintenance of running. The time course of the inhibition is consistent with the relatively high initial concentrations of naloxone exerting an agonist action and the subsequent lower levels having an antagonist effect.

Deprivation and satiation: The interrelations between food and wheel running.

Two experiments were designed to assess whether depriving rats of food would increase the reinforcement effectiveness of wheel running (Experiment 1) and whether satiation for wheel running would decrease the reinforcement effectiveness of food (Experiment 2). In Experiment 1, a progressive-ratio schedule was used to measure the reinforcement effectiveness of wheel running when rats were deprived or not deprived of food. Completion of a fixed number of lever presses released a brake on a running wheel for 60 s, and the response requirement was systematically increased until the rat stopped pressing or until 8 hr had elapsed. The ratio value reached (and the total number of lever presses) was an inverted-U function of food deprivation (percentage body weight). In Experiment 2, when wheel running preceded test sessions, fewer food-reinforced lever presses were maintained by the progressive-ratio schedule, and responding occurred at a lower rate on a variable-interval schedule. An interpretation of these results is that deprivation or satiation with respect to one event (such as food) alters the reinforcement effectiveness of a different event (such as access to wheel running).

The applied importance of research on the matching law.

In this essay, we evaluate the applied implications of two articles related to the matching law and published in the Journal of the Experimental Analysis of Behavior, May 1994. Building on Mace's (1994) criteria for increasing the applied relevance of basic research, we evaluate the applied implications of basic research studies. Research by Elsmore and McBride (1994) and Savastano and Fantino (1994) involve an extension of the behavioral model of choice. Elsmore and McBride used rats as subjects, but arranged a multioperant environment that resembles some of the complex contingencies of human behavior. Savastino and Fantino used human subjects and extended the matching law to ratio and interval contingencies. These experiments contribute to a growing body of knowledge on the matching law and its relevance for human behavior.

What happened to analysis in applied behavior analysis?

This paper addresses the current help-oriented focus of researchers in applied behavior analysis. Evidence from a recent volume of JABA suggests that analytic behavior is at low levels in applied analysis while cure-help behavior is at high strength. This low proportion of scientific behavior is apparantly related to cure-help contingencies set by institutions and agencies of help and the editorial policies of JABA itself. These contingencies have favored the flight to real people and a concern with client gains, evaluation and outcome strategies rather than the analysis of contingencies of reinforcement controlling human behavior. In this regard, the paper documents the current separation of applied behavior analysis from the experimental analysis of behavior. There is limited use of basic principles in applied analysis today and almost no reference to the current research in the experimental analysis of behavior involving concurrent operants and adjunctive behavior. This divorce of applied behavior research and the experimental analysis of behavior will mitigate against progress toward a powerful technology of behavior. In order to encourage a return to analysis in applied research, there is a need to consider the objectives of applied behavior analysis. The original purpose of behavioral technology is examined and a re-definition of the concept of "social importance" is presented which can direct applied researchers toward an analytic focus. At the same time a change in the publication policies of applied journals such as JABA toward analytic research and the design of new educational contingencies for students will insure the survival of analysis in applied behavior analysis.

The basic importance of applied behavior analysis.

We argue that applied behavior analysis is relevant to basic research. Modification studies, and a broad range of investigations that focus on the precipitating and maintaining conditions of socially significant human behavior, have basic importance. Applied behavior analysis may aid basic researchers in the design of externally valid experiments and thereby enhance the theoretical significance of basic research for understanding human behavior. Applied research with humans, directed at culturally-important problems, will help to propagate the science of human behavior. Such a science will also be furthered by analogue experiments that model socially important behavior. Analytical-applied studies and analogue experiments are forms of applied behavior analysis that could suggest new environment-behavior relationships. These relationships could lead to basic research and principles that further the prediction, control, and understanding of behavior.

Applied behavior analysis: New directions from the laboratory.

Applied behavior analysis began when laboratory based principles were extended to humans inorder to change socially significant behavior. Recent laboratory findings may have applied relevance; however, the majority of basic researchers have not clearly communicated the practical implications of their work. The present paper samples some of the new findings and attempts to demonstrate their applied importance. Schedule-induced behavior which occurs as a by-product of contingencies of reinforcement is discussed. Possible difficulties in treatment and management of induced behaviors are considered. Next, the correlation-based law of effect and the implications of relative reinforcement are explored in terms of applied examples. Relative rate of reinforcement is then extended to the literature dealing with concurrent operants. Concurrent operant models may describe human behavior of applied importance, and several techniques for modification of problem behavior are suggested. As a final concern, the paper discusses several new paradigms. While the practical importance of these models is not clear at the moment, it may be that new practical advantages will soon arise. Thus, it is argued that basic research continues to be of theoretical and practical importance to applied behavior analysis.

Choice, matching, and human behavior: A review of the literature.

This review concerns human performance on concurrent schedules of reinforcement. Studies indicate that humans match relative behavior to relative rate of reinforcement. Herrnstein's proportional matching equation describes human performance but most studies do not evaluate the equation at the individual level. Baum's generalized matching equation has received strong support with humans as subjects. This equation permits the investigation of sources of deviation from ideal matching and a few studies have suggested variables which control such deviations in humans. While problems with instructional control are raised, the overall findings support the matching law as a principle of human choice.

Activity anorexia: An interplay between basic and applied behavior analysis.

The relationship between basic research with nonhumans and applied behavior analysis is illustrated by our work on activity anorexia. When rats are fed one meal a day and allowed to run on an activity wheel, they run excessively, stop eating, and die of starvation. Convergent evidence, from several different research areas, indicates that the behavior of these animals and humans who self-starve is functionally similar. A biobehavioral theory of activity anorexia is presented that details the cultural contingencies, behavioral processes, and physiology of anorexia. Diagnostic criteria and a three-stage treatment program for activity-based anorexia are outlined. The animal model permits basic research on anorexia that for practical and ethical reasons cannot be conducted with humans. Thus, basic research can have applied importance.

Diurnal variation of intensive running in food-deprived rats.

Manipulation of the food supply can induce either intense hyperactive wheel running or a fatal activity anorexia in rats that is strongly analogous to that seen in humans. The abnormal behaviour is accompanied by alterations in the diurnal pattern of activity. As part of a detailed study of hyperactivity and anorexia, spontaneous wheel running by male rats was studied under three conditions: ad libitum feeding; restriction to 15 g of food per day; and restriction to a single 90-min meal per day. Ad libitum fed rats increased their running at the rate of 440 +/- 60 m/day per day, stabilizing after day 10 at 6045 +/- 3010 m/day. The running occurred in short bursts throughout the dark period and at the beginning of the light period. Rats restricted to 15 g/day increased their running at the significantly greater (p < 0.001) rate of 1230 +/- 120 m/day per day, reaching 12 200 +/- 4 090 m/day by day 10 and thereafter stabilizing at 13 600 +/- 4 160 m/day. The running was initially triphasic and confined to the dark period but eventually progressed to a biphasic pattern. The rats restricted to a single 90-min access period to food each day showed an even greater rate of increase in running, attaining 1930 +/- 288 m/day per day (p < 0.02 vs. 15 g/day group). These animals decreased eating and decompensated by day 4. The diurnal pattern of activity was disturbed from day 1 of the protocol, and by day 4 the rats ran essentially continuously throughout the daily cycle. The sensitivity to hyperactivity is a function of the severity of food restriction in this animal model of hyperactivity. It is paralleled by a marked disturbance of the diurnal pattern of activity, suggesting that the hyperactivity is related to a basic central nervous system dysfunction.