Running can be performed as a sprint discipline on the track over a few meters up to 10 km to the marathon and ultramarathon running distances over hundreds to thousands of kilometers. Running performance is influenced by a variety of anthropometric and training factors. Morphological features such as skin fold thickness, body fat percentage, circumferences and length of limbs, body weight, body height and body mass index (BMI) seem to have an influence on the running performance. The training volume and running speed during training are also correlated with running performance. When all variables were investigated comparatively, body fat and running speed during training were usually the most important influencing factors. For longer running performances (over 6 hours or 100 km, respectively), the aspects of experience (number of successfully finished races) and personal best times were, however, far more important than training volume or morphological characteristics such as body fat. It was also shown that ultra runners prepare differently (lower running speed and higher running volume) as runners competing over shorter distances such as half-marathon and marathon.