I am now training for marathon running and marathon swimming simultaneously for coming races in both sports.
Will this be likely to give me better or worse performance than if I only do a single sport, if the training amount and methodology is exactly the same for a single sport?
E.g. I'm swimming 4 times a week with 15 km total, and running 3 times a week with 45 km total to train for both marathon swimming and marathon running at the same time.
Will my running performance likely be better or worse if I stop swimming, and only run 3 times a week with 45 km total with the exact same structure?