When you're in the spinning class and the instructor tells you to gear into an uphill climb, you know the intensity is going up, too. It's more difficult to drive a bike upward than it is to ride on a flat surface or, better yet, coast downward with no effort at all. All leg muscles go to work when you bike uphill, but it's your "pushing" leg muscles that work hardest.
When you shift into the hill-climbing mode on the exercise bike, you probably feel it in your upper legs first. That burning sensation as you tax the quadriceps in the front of your thighs each time you press down on the pedals tells you that they are working hard to drive you onward and upward.
Glutes and Calf Muscles
Your calf muscles and glutes get in on the movement just as your pedal moves on its way to the bottom of the stroke. They both work to create that scooping motion that initiates the force that pulls the pedal from the bottom back up to the top again to give you the momentum to continue up the hill.
Hamstrings and Hip Flexors
Once your glutes and calves have gotten your bike's pedal on its way back to the top, your hip flexors and hamstrings step in for the home stretch. Your hamstrings continue the pulling motion that your glutes and calves started when the pedal was almost at the bottom, and your hip flexor draws your leg up to get it into position to press down on the pedal again. In their book on mountain biking skills, Brian Lopes and Lee McCormack point out that the hamstrings and hip flexors don't get as much of a workout as the rest of the leg muscles on a bike ride. They still get some exercise, but essentially your hamstrings and hip flexors are just working to pull one foot up fast enough to stay out of the other foot's way as it presses down.
It's not just your muscles that get worked when you put your exercise bike into hill-climbing mode. Certified personal trainer Robin Reichert lists cycling -- specifically uphill -- as one of the top five cardio exercises when you're looking for ways to burn calories. Reichert writes that biking uphill increases the resistance and the intensity of the workout you get on a bike, whether traditional or stationary, giving you an effective cardio workout that will also improve your endurance.
Elle Di Jensen has been a writer and editor since 1990. She began working in the fitness industry in 1987, and her experience includes editing and publishing a workout manual. She has an extended family of pets, including special needs animals. Jensen attended Idaho and Boise State Universities. Her work has appeared in various print and online publications.