Fatigue time in sheep with lung injury. Experimental vs model predicted time to fatigue for ramping exercise and increasing damage levels. Control sheep and shock tube damaged sheep were run to fatigue on a treadmill. Runs began at 0.67 m/s and increased by 0.22 m/s every 90 seconds until the sheep fatigued. Run speed was held constant once reaching 2.22 m/s. The model predictions are based on the muscle fatigue module in the DPM, as described previously .