10 Types of Low-Impact Exercise That Keep You Fit and Injury-Free

Maybe you've made exercise part of your daily routine, even a big part of your life. So what do you do when your knees start hurting and your doctor tells you to cut down on your daily runs?

The problem becomes finding a way to keep up your cardio workouts without the impact on your joints. Here are some suggestions of gentler ways to stay in shape — with a caveat: Just like with any other workout, you only get out of low-impact activities what you put into them.

Read more: 7 Reasons to Do Moderate-Intensity Exercise More Often

As an all-over low-impact workout, swimming is hard to beat. Immersion in water creates two advantages for your body: buoyancy reduces stress on joints and ligaments, and the water creates resistance. Water also cools your body as you move, eliminating the risk of overheating and keeping you more comfortable.

If you're concerned swimming won't be a sufficient exercise, rest assured it will give you a good workout. According to Harvard Health Publishing, swimming creates an energy expenditure that is four times that of running the same distance. In other words, swimming one mile burns the calories of a four-mile run.

Whether you're riding a $7,000 road bike or a hand-me-down Schwinn, cycling gives you as gentle or as intense a workout as you want — without pounding on the joints. Riding a bike comes with huge cardiovascular benefits but is easy on the joints, according to Harvard Health Publishing. Cycling also helps build muscle, especially in your glutes, quads and calves.

If you a biking newbie, cycling clubs in many cities and towns organize group rides. Or if you're competitive, there are races ranging from short distances to hundred-mile marathons. But safety is paramount: Always observe traffic rules and wear a helmet and bright colors to make yourself visible to motorists.

Read more: 11 Best Stretches to Do Before Biking

Rowing is one of the oldest Olympic sports and one of the few low-impact exercises that work all the big muscle groups. It's great for strengthening your abs and lower back. And rowing burns more calories than cycling or running for the same amount of physical effort, says Frederick C. Hagerman, director of the Work Physiology Lab at Ohio University.

Although you can get the benefits with your gym's rowing machine, the real fun comes from getting on the water. You can buy a lightweight open-water shell and explore some nature while getting a great full-body workout.

Start out on a local lake or flat-water river and eventually, if you're feeling brave, learn to navigate faster waters. Or try some interval training — pushing hard for a minute, backing off momentarily, then pushing again.

Tai chi — at least traditionally — is slow. Although it may not seem like a workout, it's a great option for those recovering from an injury. Commonly referenced as meditation in motion, tai chi can help maintain strength, flexibility and balance, according to Harvard Health Publishing. Not to mention, tai chi can help you develop a stronger mind-body connection, as much of the practice focuses on bodily sensations.

Tai chi sessions are usually structured with an easy warm-up of shoulder circles and neck stretching, which helps you begin to tune into your body. The instruction or practice varies according to instructor but typically includes a dozen movements. Tai chi also includes "Qigong," which is several moments of gentle breathing exercises.

Read more: Tai Chi and 5 Other Ancient Techniques That Can Benefit Your Health

Rollerblading is a great cardio exercise, especially if you're looking for a more low-impact option. Contrary to what you may believe, rollerblading can be modified to increase the challenge by bending your knees and lowering your upper body, according to A Healthier Michigan. This helps build your leg and core strength.

You can also consider doing intervals by picking up your speed for two minutes, then backing off for three. Or choose routes with a few hills. While it's an efficient means of transportation, safety is an important precaution to consider when rollerblading. Always wear protective equipment including padding and a helmet. Make yourself aware of any traffic hazards in your area, too.

Invest in a good pair of hiking boots, bring along some water and healthy snacks and get hiking. It's a great way to get some cardiovascular exercise, according to Harvard Health Publishing. Walking along uneven surfaces, especially with some added elevation, is also a great way to work your core and improve your balance.

Alongside the physical benefits, hiking is a great tool that many use to de-stress. Not only does hiking take you away from your office or computer screen, spending time in nature can be a relaxing practice. To maximize the aerobic benefits of hiking, add changes in altitude (i.e. hills) and enough distance to give you a genuine workout.

Read more: 16 Beautiful National Parks You MUST See

"Wait, isn't water aerobics an old-lady activity?" you might be saying. Not necessarily. Water's greater density means that you get more resistance to any action. Simply put, it's harder to move through water than through air. You can do all kinds of interval training in water, and some gyms offer water boot camp classes that are totally hardcore.

While water aerobic exercise can be a challenge, like swimming, it's easier on the joints. Many people report that they can also exercise in water for much longer without added muscle pain, according to the Centers for Disease Control and Prevention.

From ballroom to belly dancing, dancing will give you a great aerobic workout. There are so many variations that you're sure to find one that suits you: Bollywood, tango, merengue, tap.

In fact, the British National Health Service recommends dance "for losing weight, maintaining strong bones, improving posture and muscle strength, increasing balance and coordination and beating stress."

While most forms of dance are perfectly safe, be cautious of the higher intensity forms like ballet or hip-hop. And don't forget to have some fun! The great thing about dancing is the pleasure it gives while you're sweating your way to fitness.

Read more: Dancing and 11 Other Workouts that Improve Your Mood

There's a reason why Olympic cross-country skiers collapse at the end of their run. If you push it, skiing is a tiring workout. At competitive levels, this sport burns huge amounts of calories.

But even if you take it relatively easy, it's a great all-over workout and helps you develop greater awareness of your body movement, according to the University of New Hampshire. Alongside the calorie burn, skiing is great for strengthening the joints.

While it may seem like the horse is doing all the work, horseback riding can still give you a decent workout. Once you've made it into the saddle, you'll quickly learn that keeping up with the horse's movement requires some genuine physical effort and leg strength. In fact, horseback riding can burn up to 200 calories in an hour, according to a 2015 study published in the International Journal of Exercise Science.

Horseback riding also recruits a lot of the big muscle groups of the body. It improves muscle control and improves muscle strength, according to a 2015 study published in the_ Journal of Physical Therapy Science_. Sitting on a horse's back requires that you maintain good posture, resisting the body's desire to move with or sway with the animal.