These case reports describe a stationary cycling intervention and outcomes for two child participants (P1 and P2) with spastic diplegic cerebral palsy. Each child completed a 12-week, 30-session cycling intervention consisting of strengthening and cardiorespiratory fitness phases. P1 exhibited higher training intensities, particularly during the cardiorespiratory phase. Average training heart rates were 59% and 35% of maximum heart rate for P1 and P2, respectively. Lower extremity peak knee flexor and extensor moments, gross motor function (Gross Motor Function Measure (GMFM-66)), preferred walking speed (thirty-second walk test), and walking endurance (600-yard walk-run test) were measured pre- and postintervention. Changes in outcome measurements corresponded with differences in exercise intensity. Greater gains in peak knee extensor moments, GMFM-66 scores (+4.2 versus +0.9), 600-yard walk-run test (-29% versus 0%) occurred for P1 versus P2, respectively. Preferred walking speeds did not increase substantially for P1 and decreased for P2.