It's estimated that about 64 percent of adult women are overweight or obese, according to the Weight-control Information Network. Excess weight can affect your quality of life, and how your body moves. Exercise is an integral part of a weight-loss program, and a healthy lifestyle. The pressure on your knees varies with your body weight and if you're walking, running or cycling.
Knee Anatomy and Function
Your knee is a complex joint made up of four bones, ligaments, tendons and cartilage. The primary motions at the knee are flexion, or bending, and extension, or straightening. These motions are the motions that occur during walking, running and cycling. But there is also slight rotation at the joint that's not as noticeable. If any component is compromised by traumatic or overuse injury, or a medical condition, it can affect the function of the joint. Excess body weight increases the workload of the knees, so a healthy body weight can keep your knees healthy too.
Cycling is a non-impact activity. This means your body weight is not multiplied at all on your joints when you perform cycling. This is good news for your knees, as they only push and pull against the resistance of the bike itself. If you have knee issues that are affected by your body weight, cycling may be a good choice for your cardiovascular exercise. However, it's a repetitive motion and, just like any activity, overuse injuries are possible.
Walking is often the exercise of choice for those starting an exercise program, or who need to lose weight. It's low impact and doesn't require any special equipment other than a good pair of shoes. Low-impact activities mean one foot is always in contact with the ground. But just because it's low impact doesn't mean weight doesn't affect your knees. The force on your knees when walking is about three times your body weight. So a 200-pound person's knees are actually getting about 600 pounds of pressure during a walk. For every pound you lose, you're taking about 3 pounds off your knees.
High-impact running forces can be about four to eight times more on your knees than walking, according to the Chester Knee Clinic & Cartilage Repair Centre. So if you're 200 pounds and start running, your knees are feeling about 800 to 1,600 pounds of pressure. Running is often a choice for weight loss if your knees and other joints are healthy. But if you have a lot of weight to lose, then start with a low-impact choice and work up to running to keep your knees healthy.
Bethany Kochan began writing professionally in 2010. She has worked in fitness as a group instructor, personal trainer and fitness specialist since 1998. Kochan graduated in 2000 from Southern Illinois University with a Bachelor of Science in exercise science. She is a Certified Strength and Conditioning Specialist, Certified Personal Trainer, Medical Exercise Specialist and certified YogaFit instructor.