step up with knee up+biceps curl.
this move will work your lower body (glutes/quads/hamstrings) as well as your biceps and your core since you must use balance.
start with a dumbbell in each hand and stand shoulder width apart in front of a bench.
step up with your left foot
bring your right knee up to your chest and complete a biceps curl at the same time you raise your knee
step back down with your right foot
complete the sequence again with the opposite side.
after you have completed a step up with knee up+biceps curl with each leg~that is one rep. i like to do 3 sets of 15 reps.