The purpose of this study was to find out the Effect of stair climbing and sand dune running oselected strength variables (Leg Strength, Back Strength) of school boys. The primary responsibility of the investigator is to adopt the appropriate experimental methodology before proceeding with data collection. A pretest-posttest randomized group design was used. Randomly selected schools boys (N=45) were divided into three groups. Each group consisted of fifteen school boys (n=15). Before the training pre test was taken for all the groups on the selected criterion variables, strength variables, variables. The control group did not undergo any type of training. Stair climbing training was given to the experimental group I and sand dune running was given to the experimental group II on alternate days in the morning for a period of twelve weeks. At the end of experimental period the post test was conducted on all subjects and data collected on criterion variables. The difference between the initial and final means of the groups was considered as the effect of respective treatments. The data obtained were subjected to statistical treatment using ANCOVA. In all cases, 0.05 level was fixed to test the hypothesis of this study.