Strength a man is bestowed with in his mid 30's that isn't physically apparent to an outside observer. A man needs to do nothing to recieve it other than grow old. Many unsuspecting sons and young males looking to prove them selves "manly" aren't aware of this phenomenon and underestimate the middle aged man.
John, the better athelete, can't win a game of one on one because his Dad has man strength.
The common strength of a man that seems superhuman to all those who do not possess it. In middle school recess, if you got dared into a friendly wrestling match with that guy (every school has one)who was held-back 2 years and already had a full beard and drove himself to school, you would experience the force of man strength. The fingers seem made of steel and grapple with other-worldly force. Eventually, you will be in a full nelson so tight, you wont be able to get the air out of your constricted neck to muster a vocal signal of capitulation.
I found out that Steve has man strength. I am giving him 1/2 of my lunch money for the rest of the year.