It is better to run on roots and stones rather than on boulder paths.
Running on trails is more demanding for runners than a leisurely walk in the park, and that’s a good thing. Running while having to coordinate your movements is more demanding the more uneven the terrain. It is also more challenging for the brain, because it has to be more proactive about how to position the foot so as not to injure it.
That’s why he advises beginners to train perception through so-called proprioceptive training. Standing on one leg or balancing on a rolled-up towel are examples of exercises suitable for this training.