Knee osteoarthritis (OA) is a growing problem due to increased longevity and obesity with estimates of 14 million people living with this impairment. Knee OA results in decreased activity and lifestyle changes, further exacerbating an individual’s health. Exoskeleton technology (Keeogo™, B-temia, Inc.) may be a viable alternative to standard knee OA treatment by providing powered support to reduce pain during mobility. Preliminary studies with the Keeogo™ in six persons with knee OA showed efficacy for pain reduction during different mobility tasks. However, a tuning guide to promote better usability by clinicians and Veterans with knee OA, knowledge about the biomechanics of how the device provides active assistance, and an in-laboratory evaluation of performance outcomes compared with standard knee braces are lacking. Absence of published prescription, tuning and general guidelines for use in Veterans with knee OA were also identified as limitations. This proposal has four aims: Aim 1) to develop a knee OA-specific tuning guide for KeeogoTM that would maximize user mobility activities with reduced pain across different levels of severity of knee OA; Aim 2) to examine the biomechanical responses of Veterans with knee OA to the active assistance provided by the Keeogo™ as compared with the passive assistance provided by standard knee braces; Aim 3) to evaluate in-laboratory mobility outcomes, pain perception, and user satisfaction with the KeeogoTM as compare with standard knee braces; and Aim 4) to develop recommendations for prescribing and tuning the use of knee OA exoskeleton devices. Aims 1 and 4 are development projects and no hypotheses are generated. The two hypotheses (H) to be tested for Aim 2 are: H2.1) in stance phase, walking with KeeogoTM will show less knee adduction moment (KAM), knee flexion moment (KFM), and muscle co-contraction than walking with standard knee braces. These variables have been shown to be related to internal joint loading as well as disease progression and pain; H2.2) in swing phase, walking with KeeogoTM will show greater knee range of motion (ROM), stride length, and foot clearance than walking with standard knee braces. These variables have been shown to be related to antalgic gait as a result of knee pain. The two hypotheses to be tested for Aim 3 are: H3.1) to show improved performance outcomes on mobility tests, including a 6-minute walk test, timed up and go test, 13-step stair test, pick up penny from floor test, and the Short Physical Performance Battery (SPPB) when using the KeeogoTM as compared with their prescribed knee braces and H3.2) to show reduced pain with the KeeogoTM by the numeric pain rating scale (NPRS) as compared with their prescribed knee braces for the mobility tests. The study will be conducted at two VA medical centers. The knee OA-specific tuning protocol will be developed (Aim 1) and used in the in-laboratory evaluations (Aim 3) in 20 and 26 Veterans with knee OA, respectively, at...