For most athletes, participating in the Olympic Games is the realisation of a lifelong dream. Winning a medal is a dream beyond that, so it should come as no surprise to learn that many first-time Olympians under-perform dramatically.

We naturally expect athletes to perform their best on the stage where it matters most, but when that stage is so large and pressured, the optimal psychological balance is easily disrupted, leaving behind broken Olympic dreams.

This is the reason exposure to global platforms is so vital.

In South Africa, we use the Commonwealth Games to expose our future Olympians to the village environment, but there is little that can prepare young, inexperienced athletes for the cauldron of the Olympic Games - experience must be earned.

The pressure comes from many sources. The opening ceremony, for example, not only requires that athletes spend hours on their feet waiting for their moment to enter the Olympic stadium, it exposes athletes to the distractions and hype that can ultimately derail long-term plans.

For this reason, many medal hopefuls, particularly swimmers, will skip the ceremony in a move that many might consider absurd ("It's a once-in-a-lifetime opportunity"), but that may be a necessary part of their commitment to excellence.

Similarly, the village environment is a challenge, and athletes can be tempted by distraction and awed by the presence of so many names, many of whom they may idolise. This is at best distracting, at worst intimidating.

It is particularly troublesome after athletes complete their events and begin to relax, serving up even more distraction. Strong coaching and management are essential to maintain the focus of those yet to compete.

For their events, athletes need to achieve just the right state of arousal. Under-arousal results in an athlete who is not interested, who lacks spark and energy. Over-arousal results in even more dramatic failures, in the form of panic, or "choking", which is what happens when an athlete begins to overthink his or her performance.

Once this happens, and athletes attempt to cognitively process what is happening rather than relying on the sub-conscious and automatic execution that has been honed by years of diligent training, they will simply disappear from their event - and hope to return another day.

In both instances, pressure is to blame, and the outcome of any Olympic final is as much about how the athlete is able to handle pressure as it is about the years of training that go into the few minutes of performance before the world.

The solution to this problem, once again, is athlete preparation and management.

In particular, it is vital to manage expectations. This is typified by Chad le Clos, one of SA's star swimmers, who has acknowledged that, given that he is in his first Olympic Games at the age of 20, his objective must be to gain experience, reach finals and view anything else (the medal we hope for, but should not demand) as a bonus. He recognises that the real destination is Rio in 2016, and beyond.

The journey to Olympic glory is arduous and sometimes, because of the psychological pressure-cooker environment of the Games, it requires a trip through an Olympic Games to arrive at the Olympic podium.

Tucker is a research scientist at the UCT Sports Science Institute. His column on the Olympics will appear every Wednesday until the conclusion of the London Games. Follow Tucker on twitter @scienceofsport