 This is a phase III multicenter, randomized, double-blind, placebo-controlled, combination and component, two-period, incomplete block design cross-over study using GSK573719GW642444. The primary objective is to evaluate lung function and exercise endurance time after 12 weeks of once-daily administration of GSK573719GW642444 Inhalation Powder 12525mcg and 62.525mcg, GSK573719 Inhalation Powder 125mcg and 62.5mcg, GW642444 Inhalation Powder 25 mcg and placebo delivered by a Novel dry powder inhaler Novel DPI 