Summer weather is here, and it's getting harder and harder to force yourself to go to the gym and hit the treadmill or pick up the weights. But that doesn't mean you have to miss your workout. In fact, there are plenty of things you can do to work all your muscle groups and then some.

Jogging, cycling, rollerblading, and swimming might already be your go-to activities for a full body workout, but these lesser-known activities make ideal substitutes when you want to break away from your regular routine.

1. Go Rock Climbing

You might hit the climbing gym from time to time, but there's nothing like the rush of scaling some real-life rocks. Plus, rock climbing works upper body muscle groups including your shoulders, arms, core, and legs. It can help you to develop flexibility, but you'll also burn a whopping 500 to 900 calories per hour.

2. Have Sex

Good sex can be a full-body workout. While certain positions are more taxing than others, even good old missionary style can get your heart pumping. The next time you don't feel like going to the gym, hop in the sack instead.

3. Go to the Beach and Practice Your Handstand

Doing handstands or cartwheels on the beach might sound like a cliché, but an hour can burn you several hundred calories. Handstands activate important muscle groups in your core, and you'll have to develop balance and tone to hold one for more than a few seconds.

4. Take a Stand-Up Paddleboard for a Spin

If you live near a relatively calm body of water, stand-up paddleboarding (SUP) is a fun workout option. Be careful, though: you might just tone your entire body without realizing it. If you think SUP looks easy, you've been warned. It may be fun, but it takes some serious core strength to use the paddle to push yourself across the water.

5. Go Sailing

Sailing can be a really exciting change of pace if you're tired of your workout routine. Believe it or not, sailing can get you that total-body workout. It'll also help you to tone the muscles in your upper body, and work on agility, flexibility, endurance, and coordination. You'll burn around 200 calories per hour.

6. Try a Trapeze

For the adventurous at heart, nothing beats a trapeze workout. Pay for a private lesson or take a class to experience this adrenaline-boosting workout that can burn up to 500 calories an hour. It takes some serious ab strength to maintain control when you're upside-down and dangling from a bar.

7. Volunteer

There are plenty of activities you can do to stay active without actually working out. Some great calorie-burning volunteer activities include walking dogs for a local shelter, staffing a daycare center, coaching kids' sports, or leading outdoor activities.

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