The purpose was to compare self-chosen pace during ten repetitions of 60 m running sprints performed on a level surface (SPL), or when running uphill (SPU) or downhill (SPD) on a 4.7% slope. When expressed as percent of maximal running speed for corresponding condition, SPD was lower than SPL (95.28 +/- 1.93 vs. 97.31 +/- 1.29%; P = 0.044), which was lower than SPU (97.31 +/- 1.29 vs. 98.09 +/- 0.74%; P = 0.026). Heart rates, blood lactate concentrations and general perceived exertion were lower during SPD (163.8 +/- 8.3 bpm, 11.66 +/- 1.24 mmol L( -1), and 4.1 +/- 1.0) than SPL (169.8 +/- 7.8 bpm, 13.69 +/- 0.33 mmol L(-1), and 5.8 +/- 0.6), which were lower than SPU (174.9 +/- 8.7 bpm, 15.27 +/- 0.02, mmol L(-1), and 6.3 +/- 0.5) (P < 0.05 for all analyzes). Results show that the level of eccentric muscle loading influences the pacing strategy.