Using those machines will not cause you to gain muscle in the legs. They are cardio machines. If after using them you feel like your leg muscles have grown it's because either:
A) You are consuming too many calories and fat is being added to your body- not from the machines though!!
B) You are retaining water.
It is vitally important to have your nutrition on track to avoid both of the above scenarios. If your nutrition is excellent... then using the cardio machines will not cause muscle gain.