As a counter example, I remember listening to a radio interview with a woman who accidentally joined a boxing gym, and decided to roll with it. Even after 3 years training, it apparently took new men about 6 weeks to blast past her in strength.
And jumping back to my earlier comment. Societies tend to amplify differences. Men are stronger, so are expected to do jobs requiring strength. This, in turn leads to stronger men, reinforcing the stereotype.
In short, there's not much baseline difference between men and women. There are however differences. Societies and cultures often amplify them, particularly when it improves division of labour. In an agrarian society they might not be able to afford the split, so the situation you read about plays out. Men can't afford to powerhouse, while women need to pick up significant physical labour.