the scientific litteratur and the programs of the world elite prove that mid-long distances runners need to do volumes of easy running around 60-70% of HRMAX. Its hard to argue otherwise and its a hugh problem in relation to having a focus on intensity and movement quality.
Periodization, staying injury free and slow progression is the key. Reducing running volume on a regular basis while keeping aerobic intensity high is a great way to progress past stagnations.
The key is also to start young with focus on intensity and movement quality. Its very hard to change the physiologi of children. They dont respond well to either aerobic or strength work.
Of cause its possible to create results without high running volume… and this is particular relevent if the athlete has alot to work on without many years of training at hand.