We examined hormonal responses to slow movement exercise involving concentric (CON) and eccentric (ECC) actions. Nine men performed knee extension exercises: (1) low-intensity exercise with slow CON contractions (5-1; 5 s for CON and 1 s for ECC); (2) low-intensity exercise with slow ECC contractions (1-5; 1 s for CON and 5 s for ECC); (3) low-intensity exercise with slow CON and ECC contractions (3-3; 3 s for each contraction); and (4) high-intensity exercise at normal velocity (1-1; 1 s for each contraction). Lactate concentration was significantly higher after the 5-1 than after the 1-5 (P < 0.05). Slow movement exercises significantly raised the concentrations of plasma epinephrine, serum growth hormone, and free testosterone (P < 0.05). Serum growth hormone concentration increased to a greater extent after the three slow movement trials compared with the normal movement trial (1-1). However, serum cortisol concentration was significantly higher after the 5-1 than after the 1-5 and 1-1 (P < 0.05). Average V(O)(2) throughout the exercise session (divided by the time to complete exercise session) was significantly higher in the 1-1 (P < 0.05), with no significant difference among the slow movement trials. In conclusion, low-intensity exercises with slow movement acutely increased anabolic hormone concentrations regardless of the time to complete CON and ECC actions. In contrast, low-intensity exercise with slower ECC action stimulated smaller changes in lactate and cortisol compared with low-intensity exercise with slower CON action.