There are two ways to put more stress on a muscle:
- use a heavy weight, like benchpress, using an exercise that targets multiple joints, hopefully the muscle you want to target gets the brunt of the stress (pec instead of the arms(if they are too strong links)) and you have no weak links (delts that prevent a big bench).
- using an isolation exercise like kickbacks for triceps. However more precise, you cannot use much weight.
However nobody has built big arms on triceps kickbacks and concentration curls alone.
Ideally we want to use exercises that AND allow for a challenging weight AND targets the muscle we want to train for optimum intensity.
Depending on your built/ biomechanics etc.. it might mean that FLAT BENCHPRESSES are not specific enough or that FLYES not allow for enough weight for stimulus.
HOWEVER I think allmost anybody can good a workout out of solely DUMBELL PRESSES for chest, it's a the marriage of relatively heavy weight and decent isolation that render the results:
- 12-10-8-6 incline dumbell press
- 12-10-8-6 flat dumbell press
- 12-10-8-6 decline dumbell press
Using dumbell presses for incline/flat/decline, you built stabilizing muscle/neural pathways fast and soon you become a dumbell pressing specialist that kicks around serious weight with 10 reps
Other Exercises I have found to be a good middleground between raw power and isolation exercises are:
BICEPS:
- seated alternate dumbell curls (instead of barbell curls or pullup)
- larry scott curls
TRICEPS:
- lying dumbell extension
- weighted dips between benches
QUADS
- front squats (instead of back squats)
UPPER BACK
- dumbell row
- medium grip pulldown to front
HAMSTRINGS LOWERBACK
- stld (instead of normal deadlift)
DELTS
- arnold presses
This doesn't mean that you should avoid the BIG movements like backsquat, bench, millitary press, t-bar, barbell row,
However If you feel that one of these exercise does not work for you because of:
- not specific enough (bad form or unfavourable biumechanics, weak links)
- injuries (rotator curve, lower back)
- big butt (back squat)
- etc...
Than it might be a good idea to go with these exercises