Abstract
Wearily glancing at the front entrance of the apartment building, about 100 yards away and up two flights of stairs, Chris thinks, "One more trip and I should have everything." Two boxes of supplies and a bag of assessment equipment are needed for this visit and Chris must transport everything alone. For the next visit, Chris will again be required to transport various boxes and bags. Because of increasing shoulder and neck pain, Chris resolves to stop using shoulder straps and start using bags with wheels and portable hand carts for the boxes and other bulky supplies these visits require.