Predictor variables for marathon race time in recreational female runners We studied at 29 marathon runners, whether characteristics of body construction or rather the training has an influence on the marathon time. The evaluation revealed that the scope of the calf and the running speed correlated during training with the marathon time.Based on equation 184.4 + 5.0 x (scope of the calf in cm) -11.9 x (running speed in training in km / h), the marathon time can be estimated for women. The study can be found under https://pubmed.ncbi.nlm.nih.gov/22942994/