It is beneficial for both worker and employer for the worker to return to work (RTW) as early as possible after an illness, injury, or prolonged absence. Because employers are ultimately responsible for the RTW decision, a medical RTW assessment is commonly required to assure that the worker is medically able to and physically capable of performing the job tasks. Consequently, many employers depend on opinions from medical providers. Valid functional capacity evaluations can provide objective measurements of work-related strength capabilities and are useful in supporting a medical provider’s opinion of a worker’s ability to RTW or fitness for duty.