Remember, these are generalisations; however, generalisations, for the most part, can be quite accurate when it comes to common trends and proclivities. Regarding the pre-Somatotype commentary, I am not as familiar with this line of typing, not sure how accurate it is, but it is interesting. Regarding the Somatotype argument (starting about halfway in at 4m 25s or so), I think this is exceedingly accurate. It ties-in heavily with the Ayurvedic Dosha system (Vata, Pitta, and Kapha equate to the Ectomorph, Mesomorph, and Endomorph to a real extent).
https://www.youtube.com/watch?v=eJUaqDzWAIM
Spiritual Wrestlings 