When your main focus during exercise is health it is necessary not only develop strength, but combine strength training with endurance to maintain muscle oxidation within the cells.

During endurance training the main source of energy comes from fatty acids, which becomes more efficient as the body and muscles adapt. This is a direct result of the muscle cells increased ability to oxidize its resources into metabolic energy. As mentioned earlier, short strength training is much different from long endurance one in many ways. In the sense of energetic sources (glycogen) it differs from the endurance training (fatty acids). This is confirmed by findings of trainees using heavier weights who do not possess growth of the mitochondrial apparatus. Slow exercising with heavier weight (bodybuilding) is followed by lesser amount of sarcoplasmic reticulum. It has been found out that those who are performing this type of exercising have slower contraction even in comparison with general population. This also confirms specific response to certain type of load (exercising). The capillary density is much lower by strength athletes than by endurance athletes which again proves the same and actually promotes trainees to combine endurance and strength training. Consider collagen in the muscle; the content of collagen is larger after exercising. If you work out too much or too often the same muscle what is going to happen? Thanks to the fact you did not fulfill the super-compensation the muscle will lose it´s strength. There has been confirmed nonlinear dependence between muscle  growth and muscle strength development. From the specific responses to the strength training, it appears to be clear that strength training should be applied according to the expected results of the specific methods and individually according to the current state of the trainee. The morphological changes of the muscles appear in a much slower pace than to the control system changes (registered for example by EMG analysis).

From the health point of view, when endurance training is combined with strength, other fitness exercises abilities are developed: not only endurance, but also speed, flexibility agility and other physical wellness attributes.

Conclusion:

For effective exercising it is essential to invoke adequate external mechanical stimulation (adequate stress), provide adequate recovery with maximal super-compensation effect and always strive for regimes catered to your own physical abilities.