 The objective for this study is to determine if daily exercise using All-Stim 2 stimulation of quadriceps muscles will increase leg strength and improve outcomes duration of hospitalization, long term mobility, long term disability for mechanically ventilated MICU patients. The investigators plan to randomize patients accepted into this protocol to administration of either sham exercise i.e. placement of All-Stim 2 units on the legs for 30 minutes a day without activation of the electrical stimulation program or active exercise placement of All-Stim 2 electrodes on both legs and stimulating quadriceps muscles to rhythmically contract for 30 minutes a day. The two groups sham and active exercise will be treated for 30 minutes a day for seven days. The effects of exercise on quadriceps strength will be assessed by measuring quadriceps force generation QuadTw in response to magnetic stimulation of the femoral nerves. The QuadTw assessment will be made immediately before institution of sham or active exercise and will repeated one day after the conclusion of the seven day training regimen. Chart review and patient follow-up will be used to determine if this treatment regimen also has an impact on clinical outcome measures, i.e. duration of hospitalization. 