It amazed me that, after I had completed such a splendid march, the 2 Lapps with me – one of them approaching 70 and the other 50 – could still run, jump and play about even though each of them had had his load to carry; not a particularly large load, admittedly, but sufficient for the route. I decided, therefore, to resolve the question that Dr. Rosén had put to me: Why are the Lapps so fleet of foot? The answer is as follows, and it is not due to one single cause but to many related causes.4