Nobody likes leg day. If you say you like leg day, you're lying to yourself and everyone around you. We can all face it, leg day sucks. It's hard, it's tiring, it's not arms or chest or shoulders or just plain ol' running. And if you do leg day right, the next day you'll look like a baby giraffe learning how to walk. Or a drunk girl in heels, whichever metaphor suits your fancy.

Now, here are some actual scientifically proven reasons why you should NEVER skip leg day:

1. You'll burn more calories.

Exercises such as squats, deadlifts, or lunges make your heart and brain work harder, increasing your metabolism more and helping you burn more calories than working a smaller muscle group. Whether or not you're actually trying to lose weight, we all want to burn a few extra calories, right?

2. You'll improve your balance.

Those giant biceps aren't going to stop you from falling on your ass on a patch of sidewalk ice. Having a strong lower body will (or at least help). Balance is essential for maintaining control of your body, so as much as it sucks, go do those lunges you promised yourself you'd do last week, and the week before that, and probably for the last month.

3. You'll relieve lower back pain.

I love Netflix as much as the next guy (actually I probably love it more than the next guy), but sitting all day actually causes a lot of back pain due to short, tight hip flexors and weak hamstrings. Being active and working those leg muscles will not only help you burn off that pizza you ate last night, but will stop that throbbing back pain, too.

4. You'll reduce risk of injury.

Believe it or not, but that guy with the super jacked upper body and chicken legs is probably going to hurt himself when he finally decides to make his legs proportional to his biceps. Performing functional exercises, such as squats or lunges, promotes stability in the knee, which can avoid the always feared ACL tear.

5. You'll run faster and longer.

Leg exercises help develop your hips, which are often injury prone areas for many runners. Strength training can help athletes have a leg up (literally) on competition because of increased muscle mass.

Besides all of these legitimate reasons, you also don't want to look like these guys.