***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To use youth and parent demographic factors , youth assets ( strengths ) , and community constructs to develop age-group-specific profiles for youth who abstain from sexual activity . METHODS Data were collected using  in-person interviews of youth ( N = 1253 ) residing in r and omly selected , inner-city neighborhood households . Data were analyzed to create classification trees . RESULTS Results indicated that assets typically were the most important factors related to abstinence and that the profiles differed for each age group . CONCLUSIONS When sexual abstinence is considered , the influence of youth and parent demographics , youth assets , and community factors appears to vary across adolescent developmental age periods BACKGROUND The purpose of this study was to investigate the effect of sexual activity on cycle ergometer stress test parameters , on plasmatic testosterone levels and on concentration capacity in high-level male athletes . METHODS Experimental design . Analysis of two days of testing accomplished in a laboratory setting , comparing a day with to a day without sexual activity ( control day ) . Participants . Fifteen high-level male athletes , consisting of 8 team players , 5 endurance athletes and 2 weight-lifters , participated in the study . Measures . Each subject completed the following on each test day : two maximal grade d stress tests on a cycle ergometer and a one-hour exercise stress test coupled to an arithmetic mental concentration test .  Blood sample s of testosterone  were obtained and cardiac activity of each athlete was monitored with a 24-hour ECG tape recording over the two test days . RESULTS Significantly higher differences were achieved for post-effort heart rate ( HR ) values at 5 minutes ( p<0.01 ) and at 10 minutes ( p<0.01 ) during the recovery phase of the morning stress test 2 hours after sexual activity . These differences disappeared during the recovery phase of the afternoon stress test performed approximately 10 hours after sexual intercourse took place . CONCLUSIONS Our findings show that sexual activity had no detrimental influence on the maximal workload achieved and on the athletes ' mental concentration . However , the higher posteffort HR values after the maximal stress test on the morning of sexual intercourse suggest that the recovery capacity of an athlete could be affected if he had sexual intercourse approximately 2 hours before a competition event It is well known that athletes in the United States are told to abstain from sexual intercourse prior to athletic competition . The rationale for such a policy appears to be related to the hypothesis that sexual intercourse decreases the athletes ' ability to perform efficiently and /or maximally . But the effect that sexual intercourse may have on exercise performance has not been examined widely . Very likely , the restrictions placed on athletes have little to do with the athletes ' physiological ability to substain a particular exercise intensity and /or perform maximally . The purpose of this study was to determine the effects of sexual intercourse 12 hours prior to maximal treadmill exercise on aerobic power , oxygen pulse , and double product ( i.e. , an index of relative cardiac work ) .  Eleven male subjects were tested on the treadmill with and without prior sexual intercourse . The results from the maximal exercise tests showed that aerobic power , oxygen pulse , and double product were not different . Therefore , the data suggest that it is justified to dismiss the point of view that sexual intercourse decreases maximal exercise performance 
    Output:
    
The impact of sexual activity before a sport competition is still unclear , but most studies generally seem to exclude a direct impact of sexual activity on athletic aerobic and strength performance .
The most important aspect seems to be the interval from the time of the sports competition that affects negatively the performance if it is shorter than 2 h. There are possible negative effects from some possible concurrent wrong behaviors such as smoking or alcohol abuse .
There are no investigations about the effect of masturbation in this context .