After a week or two runs can be connected to a set of exercises ordinary squats. If you do it before, it is likely that the size of the buttocks, on the contrary, will increase, because you simply build muscle. Each time you perform two - three sets of 10 - 15 squats. This exercise is more directed at improving the shape of the buttocks, but can also help and reduce their size.
After adding one or more exercises to train the muscles of the buttocks, which you like best. For example, you can perform Mahi straight or bent legs of the situation "on all fours" or lie on your stomach at the same time and try to tear off the floor straight legs and upper body without helping hands. But in order to reduce the size of this part of the body, and not to build muscle, perform these exercises should be at a rapid pace, making a lot of repetitions in one go.
Of course, to reduce the size of the buttocks, do workouts alone is unlikely to succeed. You need to burn excess fat and, therefore, will have to take care of proper nutrition, abandon fatty, salty, fried, sweet and starchy foods. Reduce carbohydrate intake, because it is due to their high content in the diet can increase the size of the buttocks.
Try to lead an active life, if at work have to sit a lot, do short breaks every hour and walk around the room. Generally useful to walk more, so try as much as possible to get somewhere not transport, and under its own power. Less likely to use elevators, climb the stairs - this is very good trains the muscles of the buttocks.
In his spare time, relax, cycling, skiing, skating, rollerblading or just walk in the park.