Contrast training is a training approach that aims at achieving the maximum level of efficiency through using various techniques of strength during the training module. In light of the importance of using diverse training approaches, the problem of lack of attention on part of coaches to the development of the ability of the muscle in junior footballers, especially during the pre-season period, the researcher seeks to identify the effects of using contrast training during the preparation period of the 2013/14 sporting season on the level of ability of the muscle in junior footballers under 17. The researcher applied the experimental method, using a pre-test/post-test design with two groups: an experimental group and a control group, as this method is suitable to the nature of the present research. The sample was purposively selected from junior footballers under 17 years of age at Al-Ahly sporting club in Jeddah, Saudi Arabia. The research core sample consisted of 40 participants assigned equally to an experimental group and a control group. The proposed contrast training program was applied to the experimental group over a 10-week period, while the control group received the traditional general training of the team prepared by the coach throughout the application period, namely the preparation period for the 2013/14 sporting season. The research found significant differences at p level of 0.05 between the means of the post-test measurements of the experimental and control groups in the ability of the muscle of junior footballers tests, in favor of the experimental group. The researcher recommends that football coaches should be informed about the importance of contrast training, especially for junior players that can achieve the maximum benefit in terms of developing muscle power and ability of the muscle.