The best runners in a triathlon make it look easy; they seem to glide along, their muscles relaxed, their gait controlled and their speed constant. And fast. These are the triathletes who don't take running for granted, as many of us do. And they work hard to make it look so easy.
Olympic champion Jan Frodeno finished last season as the top-ranked runner - he was among the top three runners in five of the seven events in the ITU World Championship series - but he recently added new run drills to his training schedule to improve his technique.
There is always work to be done, even at the highest levels of the sport. You can concentrate on speed and endurance all you like but if you are not running properly you won't be in total control. You will be slower than you should be and you'll be risking injury.
Look at our analysis of a single stride sequence.
The most common flaw, according to many running coaches and studies, is overstriding. For most people a long stride is a bad idea - it's inefficient and will almost certainly lead to injury.
Think about it: if your foot lands too far ahead of your centre of gravity, ahead of you, the result is a braking action. You are slowing yourself (and wasting energy) with every step.
Overstriding also tends to mean you are landing heel first, with a straight leg extended in front of you. This transfers impact through your heel and knees and into your hips, placing great strain on your lower body. When you run your feet should land under your body.
One way to address this is to count your strides. You should aim for 90 strides per minute with each leg. A lower count, say, 80, means you are spending too much time in the air - overstriding and hitting the ground harder with each strike.
An efficient stride for a triathlete involves a quick leg turnover, a short stride and good knee lift. This does not mean pumping your knees up and down; rather it should feel that you are driving your knees forward.
Your hips are your centre of gravity and are therefore vital for efficient running. We tend to forget about them, focusing instead on leg action and, perhaps, arm movement, but if your hips are not taking part your posture suffers and if that's off so are you.
If you allow your torso to tilt forward or if you slouch as you tire, your hips will tilt, too. Doing so places pressure on your lower back. Stand tall, with your back and torso comfortably upright - your hips will then be sitting perfectly.
If you do feel yourself slouching as you become tired on a run, take a deep breath. You will naturally straighten. Maintain that position and you're back on track.
By the time you hit the run in a race you'll have expended a lot of energy on the swim and bike sections and so it is natural that your shoulders may begin to creep up towards your ears.
You may not even notice this but it will affect your performance, causing tension through your body and a tight running style. Relaxed shoulders encourage a relaxed style, so remember to check their position. Keep them low and loose; if they rise up, let your arms hang down for a moment and shake out the tension.
These should also be loose and kept close to the body. Try not to cross your arms in front of your body; this will expend much-needed energy and cause excessive upper-body movement. Your body has enough to do without your core being forced to work harder to keep you facing forward.
Keep your arms at a 90-degree angle and drive them back but not too far forward. If they come up too high your upper body will move more. Don't clench your fists because this too increases body tension, and don't tuck in your thumb; rest it on top on top of your index finger. Imagine you are holding an egg in each hand. Don't break the eggs.
If you can hear your feet slapping onto the ground with every strike you should make some changes to your running style. Good, efficient running is light running and it will reduce the chance of injury.
It's a good idea to think about running as a kind of pedalling motion. The less time your foot spends in contact with the ground, the better.