The subject was seated with forearms and shoulders in fully depressed position. Exercise included bilateral shoulder elevation and depression, commonly termed "shoulder shrug." Weight sleeves were then added for resistance of 0.7 and 1.4 kg without contacting the wheelchair back. Repetitive shoulder shrugging was performed in four stages of exercise with a 3-minute recovery period between each stage. The first stage was done at a shoulder shrug movement frequency of 20 minutes with 0.7 kg/shoulder as resistance. The second stage was done at 40 minutes, again with 0.7 kg/shoulder resistance. Each shoulder shrug movement stage lasted approximately 2 minutes except for the last stage. Oxygen uptake was determined with open circuit spirometry. O2 and CO2 were continuously sampled throughout the trial. Heart rate was determined by 12-lead electrocardiogram, which was continuously monitored. Ventilation volume was determined for each breath by a pneumotach.