When I do bird dogs my hamstrings mainly contract instead of my glutes. Is there anything i can try to make my glutes do more of the work? I try contracting my glutes as i lift the leg and i use a dowel on my back to keep a neutral spine.
hmmm. only thing i can think of would be to vary the exercise, and instead of extending your leg straight back, keep the leg bent and try to reach the ceiling with your foot. as far as reasons why your glutes are not activating, maybe your spine is not extended? if you keep a normal or anterior pelvic tilt, that would cause an angle where horizontal extension of the legs would not activate the glutes as much, since the leg wouldn't be moving "back" relative to your spine.
check your position- you should be balanced over the centreline. Your supporting arm and leg should not be in line.