Research indicates that knee pain occurring with movement due to osteoarthritis (OA) strongly predicts the need for functional assistance and is the second leading cause of disability in the United States. Muscle strengthening through resistance exercise is one of the treatment options for OA-induced pain. According to Kevin R. Vincent, MD, PhD, most patients with knee OA experience pain and therefore do not want to be active. “This causes the muscles around the joint to become weaker, making the joint less stable and ultimately causing patients to become less functional,” he says. “Self-efficacy often decreases when patients feel like they’re not as functional as they once were or as they lose confidence in their own capabilities.”
Beyond the functional benefits of resistance exercise, there are other benefits of muscle strengthening to consider, such as psychosocial well-being, cognitive function, and self-esteem. “These factors can all improve with dumbbell sets and resistance exercise,” Dr. Vincent says. “There may also be decreases in anxiety, depression, and negative stress-related emotions.” Stronger muscles can also lower the blood pressure response to exertion and improve glycemic levels. Overall, patients who participate in resistance exercise programs tend to enjoy better outcomes with many of the other treatments used for knee OA.
Several factors must be taken into account before starting patients on resistance exercise programs. “The level of disease severity and the overall health of the patient should be considered,” says Dr. Vincent. “Physicians should understand the willingness and ability of patients to participate in these programs and then tailor them based on whether they’ll be exercising at home or in a fitness center.”
The key to a successful exercise plan is to get the patient engaged, Dr. Vincent says. “Patients must be educated about why they’re being prescribed a resistance exercise plan, the benefits of the program, and how it’s going to affect their lifestyle.” He adds that gaining patient buy-in with individualized approaches tends to correlate with the most successful outcomes.
Safe Progression & Maintenance
Any exercise program should start at a level that is based on disease severity, according to Dr. Vincent. “Patients should generally start slowly and work their way up to more challenging exercises.” Generally, patients should start at a low percentage (30% to 40%) of the maximum weight they can lift, and with high repetitions. Each week, they can progress by 5%, but physicians should monitor their range of motion and symptoms along the way (Table 1).
Although patients should not expect to be pain free while exercising, progressively increasing pain is a red flag (Table 2). “Pain should not carry over to the next day, nor should it cause limping,” explains Dr. Vincent. “If pain levels in the joint increase, they may need to back off on the exercise regimen. The pain might be caused by improper range of motion. In these cases, patients should work with physical therapists to learn the proper form for each exercise. Patients who have these responses need to assess whether they added too much weight during an exercise or if they did too many repetitions.”
Those with knee OA who are beginning a resistance exercise program should be taught to listen to their bodies. “The body is going to have a ‘ceiling effect,’” says Dr. Vincent. “This means that at a certain level of activity, joint pain may start to increase. If the patient consistently notes increased pain at a certain level or intensity of activity, this indicates that they have reached their ceiling. Patients should be informed that this is a natural course of progression during their treatment. Over time, these ceilings change as joints becomes stronger.”
Cross training can serve as an alternative for patients who have difficulty accepting their ceiling when it is reached, Dr. Vincent adds. “If patients set a goal of running for 40 minutes, but they can only do it for 20 minutes before experiencing pain, then we should direct them to find another exercise that can get them the additional 20 minutes they lose when their symptoms emerge.”
The Bottom Line
Historically, patients with knee OA have often been told by their healthcare providers to rest their joints, but research now shows that this decreases overall health and increases symptoms. “Efforts are needed to engage patients in progressive resistance exercise programs and to teach them how to monitor their symptoms,” says Dr. Vincent. “Clinicians need to make it abundantly clear that avoiding physical activity can result in decreased physical function as well as the development of other health-related issues. Patients should be encouraged to be active and informed that it’s good to participate in strength training.”
Vincent K, Vincent H. Resistance exercise for knee osteoarthritis. PM R. 2012;4:S45-S52. Available at www.sciencedirect.com/science/article/pii/S1934148212000676.
Lange A, Vanwanseele B, Fiatarone Singh M. Strength training for treatment of osteoarthritis of the knee: a systematic review. Arthritis Rheum. 2008;59:1488-1494.
Liu C, Latham N. Progressive resistance strength training for improving physical function in older adults. Cochrane Database Syst Rev. 2009;3:CD002759.
Farr J, Going S, McKnight P, et al. Progressive resistance training improves overall physical activity levels in patients with early osteoarthritis of the knee: a randomized controlled trial. Phys Ther. 2010;90:356-366.