When the weather is lousy or the pollen count is high, you may want to take your aerobic workout indoors. The treadmill and the elliptical trainer are two of the most popular cardio machines, but choosing which one is best for you can be tricky. This is especially true if you have arthritic knees.

Both the treadmill and the elliptical trainer simulate a natural walking or running motion. On a treadmill, you run or walk in place while a belt moves under you. On an elliptical trainer, you place each foot on a platform that you move in an oval-shaped motion. There are pros and cons to both machines. The best way to choose is by testing each machine and seeing how your body responds.

Osteoarthritis (OA) affects approximately 27 million Americans. There’s strong evidence indicating that moderate exercise, such as walking or elliptical training, provides numerous benefits for OA without worsening symptoms or causing disease progression. According to a report from the U.S. Office of Disease Prevention and Health Promotion, adults with OA can expect significant improvements in pain, physical function, quality of life, and mental health by engaging in low-impact physical activity for approximately 150 minutes per week.

A recent study found that people who did light exercise more than three days a week for less than two hours per day had much healthier knee cartilage than those who didn’t exercise at all. A low-impact cardio workout can help your arthritic knees in the following ways:

  • Increasing blood flow to the cartilage and delivering nutrients that keep the cartilage healthy.
  • Strengthening the muscles around the knee, which reduces pressure on the joint and lessens the wear and tear on the cartilage.
  • Promoting weight loss, which reduces stress on your knees.

If you’re jogging or running, a treadmill can put more stress on your knees compared to an elliptical trainer. But walking on a treadmill exerts about the same amount of force on the knees as using an elliptical machine. Treadmills tend to be more user-friendly and easier to use for beginners. They may also be better for building bone density.

Problems can occur when you’re ready to ramp up the intensity of your workout. When you increase the treadmill’s speed, you run the risk of putting more pressure on your knees, which may cause increased pain and irritation in the knee joint.

Safety tips

If you’ve never used a treadmill before, ask an exercise specialist or trainer for a demonstration or assistance. Before stepping on the machine, make sure you know where the on/off switch is, how to work the controls, and how to use the emergency shut-off clip or key. Never step on or off the belt while it’s moving, and wear shoes that are appropriate for aerobic exercise. If the treadmill has an incline function, consider slightly raising the grade. Research suggests that a 3 percent incline grade can reduce shock on the legs and knees by 24 percent. However, more than 3 percent incline grade can have the reverse effect and increase stress on the joints.

Using an elliptical machine is like combining stair-stepping with cross-country skiing. Instead of using a natural walking motion with the heel of the foot repeatedly striking the treadmill belt, each foot rests on a platform and moves in an oval, or elliptical, motion. This zero-impact movement allows you to increase the intensity of your workout without increasing the stress on your joints. Some elliptical machines are equipped with handles that move in conjunction with the lower body. This works out the arms, chest, and shoulders and causes the body to burn more calories. Most elliptical machines also allow you to pedal in reverse, which strengthens different muscle groups in the lower legs.

For beginners, elliptical trainers tend to have a steeper learning curve and can be awkward to use. They also don’t offer the same bone-strengthening benefits of treadmills.

Safety tips

Because the elliptical trainer can be more difficult to use than a treadmill, it’s even more important to get a demonstration and learn the controls before stepping onto one. If you’re new to elliptical trainers, you may want to avoid the moving arm handles at first. Most machines have a set of stationary handles that are easier to use. And if you have a choice, opt for machines with wider foot platforms. These machines will allow you to adjust your stance for better balance and putting less pressure on your joints.

When used correctly, both the treadmill and the elliptical trainer can be safe, effective workout options for those with OA of the knee. Depending on your specific needs and skill level, one may suit you better than the other. If you’re new to workout machines or are at a higher risk of OA, the treadmill can be a user-friendly way to safely exercise and promote bone health.

As you progress into your workout program and begin to increase the intensity of your exercise, the elliptical trainer can allow you to do so without increasing the stress placed on your knees.

Most importantly, listen to your body. If you experience knee pain or discomfort on one machine, simply try the other. If both options make you uncomfortable, try other low-impact exercise options such as a stationary bike or water aerobics.

Riding a recumbent bicycle is another option that can strengthen the quadriceps and hamstring muscles, which are extremely important when going from the sitting to the standing position.

Regardless of what exercise equipment you’re using, always check with your physician before starting a new fitness routine. If your arthritis is severe, a treadmill may be too difficult, painful, or even dangerous to use.

Remember, the worst thing you can do for your arthritic knees is to quit exercising altogether. Before giving up, talk to your doctor about ways to adapt your exercise plan to work for you.