I’ve devised a method of training that revolves around a simple concept: your body will respond to exercise stress in a matter which eases that stress in the future.
For example, if you challenge whole body musculature so that your heart gives out before your muscles, you are stressing your cardiovascular system primarily and your heart will adapt by pumping out more blood per beat.
On the other hand, if you focus on joint-specific movements against a heavy load (bodybuilding), your musculoskeletal system will increase its contractile strength by increasing contractile proteins (hypertrophy).
If you practice complex motor skills (most sports), your coordination will improve specific to that skill (muscle activation patters, mind-muscle connection).
Keep in mind that these parameters are not all-or-nothing; there is always some degree of overlap. However, you can emphasize one variable over the other if you plan correctly.
Also, within each adaptation are degrees of specificity. For instance, runners may be built for specific distances, soccer players are leg dominant while rock climbers are upper body dominant, and muscular adaptations follow a spectrum of strength and endurance (i.e. powerlifters vs. rowers). Outside of genetics, this is why athletes are built specifically for their sport (and divisions within the sport) – their bodies respond to the primary method of training.
While the concept of the limiting factor is simple, the application may require quality instruction from a competent professional with a background in Anatomy, Exercise Physiology, and Biomechanics.