This study investigated if there were acute interference effects of strength exercises on subsequent continuous and intermittent 5Km aerobic exercises. Eleven physically active males (23.1 ± 3.1 yrs, 1.75 ± 0.07 m, 70.5 ± 8.8 kg, and 58.2 ± 8.3 VO₂max) performed the following experimental sessions: A) 5 sets of 5 RM on the leg press followed by a 5km run performed continuously (average velocity of the first and second ventilatory thresholds, v∆50), B) 5 sets of 5 RM on the leg press followed by a 5km run performed intermittently (1 min run at the vVO₂max : 1 min of rest); C) 2 sets of 15 RM on the leg press followed by a 5km continuous run; and D) 2 sets of 15 RM on the leg press followed by a 5km intermittent run. Heart rate, blood lactate concentration, rate of perceived exertion, and VO₂ at the first and the fifth km were considered for statistical purposes. There were no significant effects of both strength bouts on any of the variables associated with endurance performance (p > 0.05). It seems that both maximum and strength endurance bouts do not acutely impair aerobic performance.

• Residual acute peripheral fatigue does not seem to be the only cause in the interference effect observed during concurrent training regimens.

• Peripheral fatigue mechanisms of running such as lactate concentration are not altered by prior lower volume strength exercises.

• Strength and strength endurance exercises performed before a running bout do not seem to impair the performance in the latter.