You can break down all physical pursuits into three major categories: flexibility, stamina and strength.
While the activities performed, such as yoga for flexibility, running for stamina and weight training for strength, vary dramatically, there is a crossover benefit between all of these physical pursuits.
For example, when you perform yoga to become more flexible, a residual benefit is that you will get stronger and gain more stamina. The same holds true of running. The act of running not only increases your stamina but increases your strength. However, the crossover benefit from flexibility and stamina activities tends to be small.
This is not the case with proper strength training.
Strength training gives you the greatest carryover to all other physical pursuits because STRENGTH is the BASIS for everything you do physically. Without strength, flexibility just increases joint instability and increases injury risk (think of a loose joint supported by very weak muscles). Without strength, stamina leaves you unprepared to deal with the common day-to-day demands of life. We are far more likely to be called on to pick up a child or package than to climb a flight of 100 stairs.
On the other hand, a properly applied resistance training program gives you decent flexibility and good stamina. Sure you will gain more flexibility from doing a structured yoga program and you will certainly gain more stamina from running regularly, however, the foundation of your training should be focused on balanced strength.
Resistance training also directly combats all of the “bad” things that happen to us as we age. Loss of balance, loss of muscle mass, bone and joint degeneration, and even hormone changes are all DIRECTLY and positively influenced by resistance training. NO OTHER form of exercise comes close to the overall health and performance benefits of proper resistance training. As a matter of fact, if you compare people of advanced age who do resistance training to their peers who only do stamina or flexibility training, you will typically see a stark difference. The resistance trained individuals will look very different…more toned, better mobility, better energy and a better hormone profile. They LOOK and FEEL younger.
To be clear, this post is not saying that you should ONLY do one type of exercise. In truth, the best exercise is ultimately the one that you do consistently. Someone who goes on a 30 minute stroll every day for 20 years will have better health than the hardcore workout warrior who is incredibly inconsistent. I am simply highlighting the one form of exercise that supports all other forms of activity and if you absolutely had to choose only one, then proper resistance training would be the best choice.
With that said, a complete fitness and health routine should contain a flexibility, strength and stamina component with strength as the priority. By focusing on building strength throughout a full range of motion you will reap all of the health benefits it provides… increased flexibility, increased stamina and of course more strength.