Yeah, it seems a bit on the light side. I do a lot of backpacking with heavy packs, and 30-35 kilos is a very heavy but doable weight. When you've got a 30 kilo back on, you definitely can't do physical tasks very well. Climbing and stuff is possible, but definitely more difficult, and if you slip or loose balance it much hard to catch yourself, and more likely to get an injury. Though it has to be said, I've spent many months of my life walking over difficult terrain with those kinds of weights and never seriously hurt myself. It does affect your movement rate a lot. Human maximum to lift it, to carry a short distance, to get it on your back and to carry it all day, are very different things. For me, deadlifting 76 kilos is light, getting it on my back would be very hard - I'd need a setup or help, but carrying it I could do on the flat for hours probably, if the balance were right and I stepped carefully. And I am a fat old man, who is not particularly fit.Has anyone even looked at the Encumbrance rules lately? STR + END + Athletics (STR) + Athletics (END) x 2 = You heavy load carrying capacity with a -2 penalty to all skill checks. Max human carrying potential is then (15 + 15 + 4 + 4) x 2 = 76kg or 167lbs. I am nowhere near the strongest human, but I can carry a load of half of that all day without issue. (Or could before several failed ageing rolls... lol) According to the Traveller rules, only the Strongest and Fittest humans are even capable of such a thing. So, a +1 STR for Aslan is meaningless. Ooooo! Aslan on average can lift a kilogram or two more than an average human. I doubt that would even allow for an increase in muscle mass.
The calculations seem kind of crazy a the low end. Someone with 3 STR and 3 END has literally a 12 kilo max! It seems more like it would be the weight that some would begin to find it annoying to carry, rather than the max weight someone could possibly carry.