Muscle Fatigability and Trip-specific Fall Risk in Adults With Knee Osteoarthritis

The goal of this clinical trial is to learn about how fatigue affects the risk of falling in adults aged 55-70 years with and without knee osteoarthritis. The main questions this trial aims to answer are: * Does fatigue increase the risk of tripping while walking? and * Does fatigue increase the risk of falling in response to a trip while walking? Participants will * Complete questionnaires * Wear a device that measures physical activity for 5-7 days * Complete a 30 minute walk on a treadmill * Complete the following before and after the treadmill walk: * Computer test to measure mental fatigue * Maximal strength testing * Balance test Researchers will compare adults with and without knee osteoarthritis to see if fall risk in adults with knee osteoarthritis is affected more by walking activity compared to adults without knee osteoarthritis.