What is the effect of a treadmill on the knee?

From the Guidelines

Treadmill exercise can be beneficial for individuals with knee issues when approached correctly, as it provides a low-impact, controlled environment that reduces impact forces and allows for precise adjustments to workout intensity. When using a treadmill, start with a low-impact walking program at a comfortable pace, gradually increasing duration rather than speed or incline, as recommended by the 2019 American College of Rheumatology guideline for the management of osteoarthritis of the hand, hip, and knee 1. Begin with 10-15 minutes and slowly work up to 30 minutes as tolerated. Use proper footwear with good cushioning and support, and consider a treadmill with shock-absorbing features. Maintain proper posture with a slight forward lean, short strides, and avoid looking down at your feet. If you experience knee pain during exercise, stop immediately and rest.

Some key considerations when using a treadmill for knee issues include:

• Starting with a low-impact walking program to minimize stress on the knee joint
• Gradually increasing duration and intensity to avoid exacerbating knee pain
• Using proper footwear and considering a treadmill with shock-absorbing features to reduce impact forces
• Maintaining proper posture and avoiding looking down at your feet to reduce strain on the knee joint
• Complementing treadmill walking with knee-strengthening exercises like straight leg raises and wall sits to improve stability, as recommended by the treatment of osteoarthritis of the knee guideline 1
• Applying ice for 15-20 minutes after exercise if you experience any discomfort to reduce inflammation and pain

It's also important to note that treadmill walking is generally safer for knees than running because it provides a consistent, controlled surface that reduces impact forces compared to outdoor surfaces, as supported by a study on the influence of running surface on tibial acceleration and tibial bone stress injury risk 1. The controlled environment also allows for precise adjustments to workout intensity, making it easier to stay within pain-free limits while still gaining cardiovascular benefits and improving joint mobility. Overall, treadmill exercise can be a beneficial and safe way to improve knee health and reduce pain, as long as it is approached correctly and with caution.

From the Research

Effect of Treadmill on the Knee

• The use of a treadmill, particularly a lower body positive pressure (LBPP) treadmill, has been shown to have a positive effect on patients with knee osteoarthritis (OA) 2.
• Studies have found that LBPP treadmill walking training can alleviate pain symptoms and improve lower extremity locomotion in mild to moderate knee OA patients 2, 3.
• Compared to conventional therapy, LBPP treadmill training has been found to result in greater improvements in walking speed, stride length, and knee range of motion 2.
• The reliability of pain scores during an unweighting protocol on an LBPP treadmill has been found to be moderate to good, supporting the use of pain scores as a reliable measure during exercise 3.
• Anti-gravity treadmill training has been compared to traditional treadmill training in patients with moderate to severe knee OA, with results showing significant improvements in pain, functionality, and functional capacity in the anti-gravity group 4.

Comparison of Treadmill Types

• Supervised exercises, including those using a treadmill, have been found to be more effective than home-based exercises in alleviating pain and reducing disability among patients with knee OA 5.
• Anti-gravity treadmill training has been found to be more effective than traditional treadmill training in improving pain, functionality, and functional capacity in patients with knee OA 4.
• The use of an LBPP treadmill has been found to be an effective approach for alleviating pain symptoms and improving lower extremity locomotion in mild to moderate knee OA patients 2, 3.

Clinical Implications

• The use of a treadmill, particularly an LBPP or anti-gravity treadmill, may be a useful adjunct to traditional therapy for patients with knee OA 2, 4.
• Clinicians may consider using an unweighting protocol on an LBPP treadmill to determine the body weight support needed to decrease pain in patients with knee OA 3.
• Further research is needed to investigate the long-term outcomes and effectiveness of treadmill training in patients with knee OA 5, 4.