If you do not have enough time to do your legs at the gym, then before you get in the shower do lunges either in place or walking for 5 minutes not stop. Do them in place, walking, alternating, backwards & sideways. Keep mixing up the patter, but make sure you keep track of time. If you need to pause and stretch, then stop the timer, and when you are ready to start back up again, re-start that timer. Have fun with this exercise, because you legs will really feel it.
Portland Oregon Fitness