As you pedal in a straight line, the glutes and thigh muscles are also engaged. Interesting to note is that even though it is advised to always activate the glutes, there is no need to overly try to scope or reach for the pedal in a way that a particular muscle group is targeted. Always remember to be focused on general strength and activation exercises for all muscles so that they can be utilized effectively, the cycling technique will take care of these aspects by itself.