Depending on your individual needs I will spend more time on one area than another when first you start to train for an endurance sport.
Whether Endurance (increasing your oxygen capabilities), Speed (I mean burst speed, here), Strength Training, Flexibility, and Balance; and not necessarily in that order, but close, and may vary for the individual.
The importance of each one depends on your previous experience, all the way from couch potato to fairly high performing athlete, as well as your age. You will find that each of these, especially when combined, often contribute to certain mental capabilities and improved emotional states.
ENDURANCE, or the ability for your muscles to use oxygen for an extended time, is a typical starting point for many people. Building up endurance is usually accomplished by longer periods of running, biking, swimming, at a slower pace with a lower to medium heart rate. This actually builds up the capability of muscles to utilize oxygen. Later in training you will go longer with a faster pace.
SPEED, as used here, means being able to go ‘faster than you can go’, kind of. In other words, it’s running faster than you can sustain, which means you’re beyond your oxygen using capabilities. Of course, this is for short periods of time, from seconds to a minute or so. Your “neuromuscular” coordination is improved that also helps your efficiency.
STRENGTH will help to avoid injury and increases muscular efficiency. There are several kinds of strength training, from high repetions with lighter weight, to a few repetitions with heavy weights and there are arguments for both sides. As people get older there is a greater need for more weight training, as muscle mass starts to decrease rather rapidly after age 40 or so. Training the larger muscles in the legs and the core (mid-body muscles) is particularily rewarding in terms of results for triathlon.
FLEXIBILITY is an important item as we age. Because the muscles and tendons seem to shorten, somehow, and it affects the range of motion of our joints. Of particular interest are ankles, knees, and hips (of course all the joints are important) that affect walking, running, swimming (even biking). It’s been found that as people age, their steps are shorter; this affects speed, effeciency, and mobility in general, as it takes more energy to move a stiff joint than a limber one as well as moving more slowly.
BALANCE; really important as we age, is affected by both strength and flexibility. Of course, falling is one of the biggest results of lack-of-balance, but increasing the body’s response to weight changes, such as ground level differences encountered while running, cross winds or obstacles in the road while biking, all account for balance work and quick nervous system response to these changes that are immediately fed back to the muscles. I have specific tools that I use for keep my “balance intelligence” in shape.
As mentioned at the beginning, the order of importance of each of these regarding triathlon training is pretty close to accurate. However, considering age, experience, and physical capabilities these five catagories will shift to produce the best training results.