Aim #2: A secondary aim will test if movement-pain reduction by TENS results in a concomitant decrease in fear of movement, fatigue, resting pain and analgesic medication and an increase in function and quality of life. Outcome measures will include physical function by directly assessing daily activity with an accelerometer, self-report (IPAQ), as well as performing specific function tasks. A sub-analysis will determine responders and non-responders to TENS and factors that predict both responders and non-responders. Multiple factors that could contribute to TENS response include self-efficacy, pain catastrophizing, levels of physical activity, fear of movement, sleep, pain, fatigue, function, quality of life, or pain physiology.