interesting but not necessarily true!

The majority of long-distance runners take delivery on the heel (see the 2014 study "Strike Pattern Foot and Gait Changes During a 161-km Ultramarathon"): over 80% of the riders on a 161 km race.
According to a specialist of the race (see article "Is It Harmful To Heel Strike When Running" on the website running competitor Tom Michaud), the change in stride must be justified clinically.
The curious can also refer to Blaise Dubois who used high-resolution photos to see how high-level athletes réceptionnaient, eg Olympic champion Meb Keflezghi (on the heel). Note: The specialist does not defend the reception on the heel.

My conclusion after a few hours of research if you want to change your reception because you have bad (especially the knees), then this book is very clear. But for others, changing stride is difficult (many believe does not land on the heel but do so ...) and do not bring better performance.