ok, personally from my own experience, u stop at 0.8km... that's
when ur muscles ache, u wanna give up, u feel breathless...
what i do is that, i carry on... i treat that as a warm up... after
that you'll be doing the routine jog... and ur muscles wun ache or
feel tired...
only when the second wave of aches and tiredness comes, that's when
u'r tired
that's my own theory which i apply to myself... any other
theories?