There are numerous reasons why walking the circuit is so important if you want to a) improve your racing performance, and/or b) have a more enjoyable and rewarding racing experience.
The first, and probably most important reason why you should do this is: it is the only way you can fully develop your circuit knowledge. Let's look at why:
If you observe the preparations of elite competitors, this is something that they do right across the world in any sport that requires navigating a short course in the shortest time. I usually take it for a given that an elite level motorcycle racer will not only walk the circuit but also ride it perhaps on a scooter and/or bicycle as part of this process. These elite racers will also spend time properly studying specific corners and the qualities of them to work them out. You can also observe this in World Cup skiers and downhill mountain biking, for example. In cross country mountain bike racing, although the course is sometimes too long to practically walk it, riders will ride it slowly and then get off to study the technical sections before riding them. Sometimes they'll do this several times to get a feel for the best lines. The London Olympic Mountain Bike course is a case in point where it was so technical it had to be studied - a rider could not simple barrel into it hoping for the best. This is one of the very important patterns to performing at your best and I see it as an essential component of any racer's routine. There are some simple reasons for this, but in this post I will focus on what I think is the primary one.
It is in learning the circuit:
It is a fact that learning something complex takes time and effort. It is also a fact that you will never fully know a racing circuit. The qualities of the circuit will always change and so will your perception. I have recently completed many walks with racers around, Donington Park, Snetterton 200 and 300, Silverstone and Cadwell Park, for instance,and each time we do a walk the circuit appears different. And this can be for many reasons; the weather and light conditions; you've learned something new and developed yourself so your experience has changed your perspective. This is why learning the circuit is a never ending task - if you want to get the most out of your racing - and it is something that can be part of the pleasure and satisfaction of racing.
Riding the circuit at race speeds, or even 80% of race speed will never give your brain the chance to truly get to know the circuit. Think of it like this. In club racing, if you are attending Friday test days and then Saturday and Sunday race days, you'll get 5, maybe 6, 15-20 minute test sessions or thereabouts. In racing you'll get a couple of qualifying/warm up sessions and then probably 4 races. Neither in qualifying nor racing do you have the necessary mental capacity to develop your circuit knowledge to any great extent. So with the remaining time you might, if you're lucky, get only a handful of seconds experiencing any given corner simply because you're passing through it at high speeds.
However, if you walk the circuit even just once during a race weekend, you will increase the amount of time you spend at any point on the circuit by many, many times. So merely taking a stroll is going help you out. At the very least it's going to help you gain better familiarity with the circuit.
The real benefits come from adding specific intentions to your circuit walk and setting out to study and learn it better, spending more time considering how you see the circuit, the lines that appear to you and other relevant characteristics of the track. If you then walk the circuit several times, like in the morning and evening, you will begin to see how much your perception changes and how your relationship with the circuit develops.
The most fruitful relationship comes from the interplay between circuit walks and your riding experience - each informs the other. For example, at Donington Park a rider was reporting headshake as he changed from 4th to 5th gear through Schwantz. It was assumed that this was down to suspension setup but during the track walk it became clear that there were ripples on the circuit which would account for this problem - he could then put this concern aside and free his mind for other things. At Silverstone, on the International circuit, the track walk indicated a particular line through The Link out onto Hangar Straight. When trying the line out during one of the sessions, there was actually a bump on the circuit that upset the bike too much at turn in. We didn't see the bump on the track walk so it is a prime example of how the two processes inform each other and the rider adpated his line accordingly.
Another psychological benefit that has been reported back to me is that once the riders have done their track walks, they found that during riding they had much more mental capacity available so they could focus just on the racing. In terms of lap time improvements, all riders have improved their times significantly, but I have seen measured in excess of 10 seconds per lap improvement from once session to another with only a focussed lap walk between in terms of development.
In Part 2, I will cover more of the soft psychology involved in this process and how it can generate performance improvements even further.