Forward step ups are a great functional exercise that strengthens the quadriceps muscles and mimics the every day task of going up a step or a flight of stairs.
Begin standing in front of a step or at the bottom of a flight of stairs. Lengthen your spine without arching your back and stand tall with your weight evenly distributed between both feet.
Hold onto a handrail (or two) for balance if needed.
Place your right foot in the middle of the step. Push through the right foot to step up as you lift your left knee to hip height. Stand tall on your right leg, then slowly lower back down. If you feel more comfortable, simply place the left foot on the step as you step up rather than lifting it to hip height. Repeat 10x on the right leg, then do the same on the left leg.