HA, broke 2 chains when hammering like a sob up short steep hills.
One was a Suntour, the other was a Regina (sp) hollow link chain. I don't keep chains that long, so wear wasn't an issue. I can't tell you if the Suntour chain broke where I inserted the pin. The Regina, well, it was never meant for sprinting
Both times my knee hit the hbars quite hard. Hitched a ride back home both times since there was no way the chains could be used again unless you had a machine shop right next to you. Plus, both times my knee hurt like hell.
This all happened 14-16 years ago. I've been using DA (8 & 9) and Record (8 & 10) chains ever since with no problems.