Introduction: In this study we investigated whether an association exists between muscle fiber conduction velocity (MFCV) and local muscle oxygen saturation (StO(2) ) in the superficial part of the latissimus dorsi muscle of runners and swimmers during exhaustive dynamic exercise. Methods: Participants performed arm cranking with increasing intensity until exhaustion. Results: Runners' MFCV was unchanged with increasing arm-cranking exercise intensity, but was higher (P <0.05) than swimmers' MFCV at the same workload. Swimmers' MFCV increased (P <0.05) with increasing exercise intensity and reached values at exhaustion similar to those of the runners. StO(2) was similar in swimmers and runners at rest and decreased with increasing exercise intensity. StO(2) was higher (P <0.05) at the same workload in swimmers compared with runners. StO(2) and MFCV were significantly but very weakly correlated in both swimmers and runners. Conclusion: No association exists between surface MFCV and StO(2) in either trained or untrained human skeletal muscle during exhaustive intense dynamic exercise. Muscle Nerve, 2012.