Uphill Walking as Exercise for COPD Patients

"Subjects will be prepared for data collection by wearing a form-fitting suit (i.e., wrestling singlet) and obtaining height and body weight. Retro-reflective markers will be placed bilaterally on anatomical locations of the feet, legs, and hips.~Subjects will be outfitted with the portable metabolic cart and oximeter as in the previous visit. One of two treadmill trials will be performed: 1) at the speed and 2) at the slope +speed determined in the previous visit. Trial order will be randomized among subjects and across visits 3 \& 4. For each trial, subjects will be asked to walk on a treadmill for up to 6 minutes. Speed or slope will be increased every 30 seconds and they will be asked to walk for one minute at that speed or slope."