Every extra pound of weight you carry feels like 4 or 5 pounds to your knees, says Dr. Nicholas DiNubile, clinical assistant professor of the department of orthopaedic surgery at the Hospital of the University of Pennsylvania. If you lose just 10 pounds, you can relieve your knees of up to 50 pounds of stress. Exercise helps you lose this weight by boosting your daily caloric burn, but certain machines can aggravate your knee pain too much to fit in the 250 minutes of moderate-intensity exercise per week recommended by the American College of Sports Medicine. Seek out low-impact alternatives that boost your heart rate and make you feel breathy, signs that you are working at a moderate- to vigorous-intensity.
The elliptical trainer combines the movements of running, stair climbing and cross-country skiing without any impact, making it less stressful on the knee joint. Your feet stay fixed in pedals that glide along rails to work your lower body. Many models also offer arm poles that you pump as you pedal to further increase your caloric burn. A study published in the "Journal of Sports Medicine and Physical Fitness" in June 2004 compared the effectiveness of training on a treadmill, stair climber and elliptical trainer and found that when participants worked at the same intensity, the physical effects of each machine were nearly identical. Proper use of the elliptical shouldn't hurt your knee, notes Dr. Edward R. Laskowski on MayoClinic.com. If you do feel pain, you should consult a health care provider to ensure you don't have an underlying knee problem such as degenerative arthritis.
Running or jogging on the treadmill can hurt your knee, but walking on the moving belt can be a pain-free experience. Laskowski explains that walking on the treadmill exerts about as much force as using the elliptical. If you move at a brisk pace, around 4.5 mph, you can burn 186 calories per half-hour if you weigh 155 pounds. However, DiNubile notes that walking may not be an option for people with advanced osteoarthritis.
A stationary bicycle is recommended by both doctors, especially when other machines cause pain. The bike works your quadricep muscles on the front of your thighs, which provide support for the knee joint. A moderate session on the bike burns 260 calories in 30 minutes for a 155-pound person. Therapists often recommend stationary cycling as a way to rehab from knee injury or surgery.
The rowing machine, when used with proper form, provides an excellent cardio workout for people with knee pain, according to Madeline Berky, four-time NCAA rowing champion and a personal trainer. To use the rower, sit on a sliding seat with your feet pressed against a solid platform and pull a rowing handle to your ribs. To minimize stress on the knees, keep your knees in line with your ankles and behind your toes. Moderate-intensity stationary rowing is equal to stationary cycling in terms of calorie burn -- 260 per 30 minutes for a 155-pound person.
- SynVisc One: Knee Pain Questions & Answers
- Journal of Sports Medicine and Physical Fitness: Physiological Changes Following a 12 Week Gym Based Stair-Climbing, Elliptical Trainer and Treadmill Running Program in Females
- American College of Sports Medicine: ACSM Position Stand on Physical Activity and Weight Loss Now Available
- Harvard Health Publications: Calories Burned in 30 Minutes for People of Three Different Weights
- MayoClinic.com: Elliptical Machines: Better Than Treadmills?
- Lancaster Online: Exercising Safety With Bad Knees
- Photo Credit IT Stock/Polka Dot/Getty Images