The purpose of this study find out effect of extensive and intensive interval training on muscular endurance and resting pulse rate among athletes. pre test-post test randomized group design was used for this study. The randomly selected (N=60) college men athletes were divided into three groups randomly consisting of twenty college men in each. Before the training pre test was taken for all the groups on muscular endurance and resting pulse rate. Experimental group I underwent extensive interval training, experimental group II underwent intensive interval training for twelve weeks. The control group did not undergo any type of training. At the end of twelve weeks the post test was conducted on selected variables. The difference between initial and final test scores was considered as the effect of respective training on selected criterion variables. To test the significance the obtained data were subjected to statistical treatment using ANCOVA. In all cases 0.05 level was fixed to test the hypothesis of this study.