In reply to andic:
im not expert but i lift for the same reasons you do (LMKM).
my own standards are just to copy the usuals, as layed out by guys like dan john (im an acolyte i know, but i dont know enough to make my own).
these include 2 x double body weight DL, BW clean/press, 1.5BW backsquat, 1.25 front squat, BW overhead squat, 50% BW TGU. bench im ignorant of as i cant do them properly (injury) beyond BW.
i weight 75kg and fulfil all of these simply because i need to in order to do the training program i do. im not 'strong' - just strong enough to really train. i exceed the standards unevenly (5% for some, 10% for others).
there are other cardio standards too that i think are more telling, and determine 'strength' in other ways. as a LMKM, i think cardio capacity outstrips 1RM - but then at 75kg i would...
to my mind, covering 20km with 22kgs of weight is a better indicator of functional strength than DL, but weights have their place as raw indicators.
'my' approach (ie the one i copy from elsewhere) is to think of progress as a pyramid and expand its height (1RM) by developing its base (power endurance). basically, periodize so sometimes youre pushing the reps for a month or so, then focus on pushing the peak. always do lots of supportive stuff.
i think its just the start of strength because a) people that know more tell me so, and b) it becomes apparent when applied functionally to shit like climbing and running around with a pack on.
it becomes obvious around BW level what is just technique and what is actual development of muscle/skeletal integrity.
pullups are a good example; 10 is only form and technique, 15 is that plus cardio, +20 is from having actual strong upper body (in relation to BW like the other standards).
others here know more about all this than i do. i could be way off.