Bit off-topic, but its interesting reading about the ability to swing big hammers – I believe it is all down to technique, not all brute force.
When we moved to our current location, we found we had to use wood heating, and this meant chopping between 10 and 20 tons of logs, mostly oak and ash. It usually is done around Easter, so the logs can be stacked to dry for the winter. If the wood is left for a long time, ash in particular becomes very difficult to chop.
My first attempts were feeble – I could maybe chop about three or four wheelbarrow loads, then had a 'collapse' until the next day. It would take me maybe three or four weeks to chop it all, and it was painful, to say the least.
Nowadays, after doing it for 8 years, I can chainsaw the logs into 2 foot lengths, then chop the lot in 2 or 3 days. I think its all down to technique – I learnt (the hard way), how to swing the axe properly, and I would never have believed that a 'technique' existed before I did it – but I couldn't say what is different now. I have watched skinny boys chop logs with no apparent effort. (I have just finished this years load, and I am now over 70, weigh about 70 kilos, and have no obvious muscles to speak of
).