Bone mineral density and content of collegiate throwers: influence of maximum strength.

AIM: Bone changes in size and density in response to different levels of stress. Alterations to bone mineral density (BMD) appear to occur in a site specific manner. Even though BMD has been examined in many populations there is a paucity of data looking at strength-power athletes, such as throwers. Therefore, the purpose of this study was to examine the BMD of a group of USA Division I collegiate throwers (e.g. shot put, discus, etc.). METHODS: Seven throwers (4 males; 3 females) who were 19.0 + or - 0.9 years had their BMD compared to an age matched control group (n = 14; 8 women and 6 men) and normative data. BMD was measured with dual X-ray absorptometry. Potential right/left side and sex difference in BMD were also examined. Maximal isometric strength was assessed using a mid-thigh pull while standing on a forceplate which generated force-time curves. Peak force (PF) and normalized peak force (PFa) were then correlated with BMDs. RESULTS: Generally, throwers had denser bones with male throwers tending to have a greater total BMD (P < or = 0.05). The dominant arm BMD was slightly greater when compared to non-dominant arm (P < or = 0.05). Furthermore, total body BMD was related to PF (r = 0.68, r(2) = 0.46) and PFa (r = 0.56, r(2) = 0.31). CONCLUSIONS: Throwers have greater BMDs than non-athletes and most other athletes. However, throwers only showed a small indication of sidedness. It is likely that the BMDs observed in this study stem from the training intervention (e.g. whole body heavy lifting) undertaken by this population.

Ethanol consumption in rats when dose size is under subject control.

Rats orally self-administered ethanol when they could control dose size as follows: A lever press initiated a trial; a press on 1 lever increased the previous trial duration by 30% whereas a press on a 2nd lever decreased the previous trial duration by 30%. During a trial, rats could drink either water, 8%, or 16% (wt/vol) ethanol (ETOH) from a lick-sensitive fountain. Mean per session intake of 8% and 16% ETOH was 0.8 g/kg and 1.3 g/kg, respectively. Water intake was negligible. Rats did not show a tendency to maintain a particular trial duration, nor did they adjust intertrial intervals to previous dose size (number of licks). When trials were collected into bouts, a positive relationship was found between bout size and interbout interval; this relationship was statistically significant for the 8% but not the 16% ETOH condition.

A novel paradigm to investigate regulation of drug intake in rats self-administering cocaine or heroin intravenously.

The purpose of this experiment was to investigate the regulation of drug intake in rats (n = 20) self-administering heroin or cocaine during daily 5-hr sessions. Operant chambers were equipped with 2 levers and associated stimulus lights. A response on the lever with stimuli signaling an increase in dose size increased the infusion duration by 3 s, and a response on the lever with stimuli signaling a decrease in dose size decreased the infusion duration by 3 s. Results showed that daily and hourly drug intake for cocaine and heroin groups were relatively constant. Significant correlation coefficients were obtained for heroin and cocaine groups for the relationship between interdose interval (IDI) and infusion duration (dose size). These findings indicate that subjects regulated their drug intake by adjusting IDI throughout drug self-administration sessions.

The relationships among saccharin consumption, oral ethanol, and i.v. cocaine self-administration.

The purpose of the present experiment was to replicate previously reported observations of a relationship between saccharin consumption and oral ethanol self-administration in rats using operant measures (2,8) and to determine whether saccharin intake was related to the rate of acquisition of IV cocaine self-administration. Groups of Wistar rats selected for high and low saccharin (0.1% wt/vol) intake were tested for rate of acquisition of IV cocaine (0.2 mg/kg/infusion) self-administration using an autoshaping procedure. They were subsequently tested for self-administration of oral ethanol (8% wt/vol) under ascending fixed-ratio (FR) schedules (FR 1, 2, 4, and 8). Finally, ethanol deliveries were compared under food-deprivation and food-satiation conditions under an FR 8 schedule. Saccharin intake was redetermined after each phase of the experiment. No significant differences between high and low saccharin groups were found in rate of acquisition of IV cocaine self-administration, and there was not a significant correlation between saccharin and cocaine consumption. However, the high saccharin group drank significantly more ethanol than the low saccharin group during the FR 8 food satiation component. A significant correlation between saccharin and ethanol consumption was also found. For high and low saccharin groups, responding for ethanol increased proportionally with increases in FR such that consumption of ethanol remained relatively constant as FR increased. Ethanol consumption was significantly increased under food deprivation relative to food satiation conditions for both saccharin groups. A significant correlation between ethanol consumption and cocaine consumption was also found. Significant increases in saccharin consumption across successive saccharin consumption tests were found for both groups, although relative intake for the high and low saccharin groups remained stable throughout the experiment. These results indicate that higher ethanol intake is predicted by higher saccharin intake, but saccharin intake did not predict the rate of acquisition of IV cocaine self-administration.

Effects of tobacco abstinence on food intake among cigarette smokers.

The total caloric and specific nutrient intakes of smokers who became abstinent were compared with those of a control group. Both groups were composed of volunteer inpatients housed in a research ward for 7 days. After smoking ad libitum for 3 days, the experimental group was required to abstain from tobacco for the next 4 days while the control group continued to smoke. Significant increases in total caloric intake and in grams of carbohydrates, protein, fat, and sucrose were observed in the experimental relative to the control group, whereas no significant differences were found in fructose intake. The increase in caloric intake was not specific to increases in snacking. Preliminary analyses showed gender differences in food intake as a result of tobacco abstinence.

Relapse among alcoholics with phobic and panic symptoms.

A group of 35 alcoholics who indicated they had symptoms of phobia, panic, or both (the anxiety problem group) were compared to their matched controls who did not indicate having anxiety problems. Comparisons of relapse rates, reasons for relapse, and rates of emotional problems at six months posttreatment were made. Results showed that although relapse rates were similar between the two groups, significantly more anxious subjects reported relapsing to cope with depression and experiencing problems with nervousness, tension, and anger posttreatment. Implications for treatment and the need for further research are discussed.