The relationships between dynamic stability, lower extremity strength, and functional performance are not well-understood for individuals with knee pain due to osteoarthritis. The series of studies presented in this dissertation incorporate the assessment of functional movements for healthy older adults, individuals with symptoms of knee osteoarthritis, and individuals following total knee arthroplasty. The functional activities investigated in these populations included stair descent and sit-to-stand. This research was completed through a combination of kinematic techniques of motion analysis and kinetic assessment using multiple force platforms to evaluate joint moments, center of pressure parameters and weight-bearing asymmetry. The findings can be summarized as follows: 1) Kinetic and kinematic indicators of sit-to-stand movement may be standardized for healthy individuals of various ages without regard to initial positioning; 2) Individuals post-total knee arthroplasty compensate for residual physical deficits by utilizing upper extremity support and altered joint loading to perform sit-to-stand successfully; and 3) Altered joint loading and compensatory weight-bearing asymmetry allows individuals with mild to moderate knee pain to perform sit-to-stand and stair descent while maintaining dynamic stability. Older adults with symptoms of osteoarthritis appear to compensate for physical limitations of reduced joint mobility, strength deficits, and pain by adjusting joint loads and altering patterns for movement.