When a program goal such as increased VO2max has been selected, the objective completion of that goal could be determined by comparison to baseline data. Unfortunately, few measures of physical activity have been validated in children with disabilities (Fernhall & Unnithan, 2002). Fernhall and Unnithan (2002) outline several possible protocols that could be used: doubly labeled water, direct observation, surveys, heart rate monitoring, and activity monitors. Pros and cons for each method are provided (Fernhall & Unnithan, 2002). The same issues, namely lack of validated test methods, also plague measurements of work capacity in this population for maximal, submaximal and field tests (Fernhall & Unnithan, 2002). The protocol for measuring work capacity in children can not mimic that of adults for many reasons noted by Fernhall and Unnithan (2002). For example, the usual maximum heart rate formula (220-age) "is invalid in children because the maximal heart rate of children does not change from age 5 years through adolescence" (Fernhall & Unnithan, 2002).