Tuesday, August 14, 2012

Ergogenics.. Improving race day performance



By definition it is the tendency to increase work output. Nutrition is a prime example. Consume carbohydrate during prolonged exercise and you can exercise for longer, plain and simple. The mechanism behind the ergogenic effect of carbohydrate ingestion is two fold. Firstly it provides a fuel source for contracting skeletal muscle. However, secondly and of a more complex and less understood nature it staves off the fatigue signals monitored by the brain.

Here we now have two vastly different components that we can target with a little physiological knowhow. i) a peripheral mechanism; being the muscle its-self and the metabolic complexity that is required for continued muscle contraction. ii) the central component; The brain and nervous system that monitors the energy status of the body and ultimately regulates intensity and duration of exercise based upon feedback from the periphery.

Nutritional ergogenic aids can be classified into two main categories. Ones that targets the periphery such as sodium bi-carbonate, nitrates and also fuel substrates such as carbohydrate. These aids all help sustain muscle contraction by either supplying a fuel source, maintaining homeostasis such as pH levels or by assisting biochemical reactions that result in a greater yield of energy production for muscle contraction.

In contrast we have the aids that work on the central component, these being the ever so common stimulants such as caffeine. The central nervous system is what drives the muscles and if we can ‘turn up the dial’ of the output from the brain then the muscle will respond and contract with greater force. Central stimulants weather they be natural or synthetic are simply mimetics that act very similarly to the bodies own hormones. If you stimulate the nervous system the neural drive to the muscles is increased, the cardiovascular system pumps more blood and the body is better equipped to deal with a life threating situation. After all, this ‘flight or fright’ response initially evolved so we could escape danger back in our early years of evolution. Fortunately for athletes enhancing sporting performance works along similar lines. Perhaps adding a little danger to our next race may help crack a few new PB’s?

The power of this up regulation of the central nervous system on human performance is probably best outlined by the old wives’ tale of a mother lifting a car off her child. A super human effort that may be beyond belief but if indeed true may just outline the actual limits of human performance under the right circumstances.

Science has shown that central stimulants can improve performance in a range of events and can be as effective as eliciting a ~1-12% improvement in performance. Notably however is the large inter-individual variation in this performance improvement. Some respond well and others don’t.. so trying your chosen strategy prior to race day is essential. Preferably under controlled conditions so you can monitor any performance improvements.

My latest research project was based on the premise that we can improve performance using ergogenic aids. But more precisely what happens if we combine an ergogenic aid that targets the peripheral mechanisms with one that targets the central component? Theoretically we should get a combined effect. For example consuming dietary nitrate in the form of beetroot juice has now been repeatedly shown to improve time trial performance. It exerts its effects on the muscle itself by increasing blood flow and somehow reducing the oxygen cost of muscle contraction thus, increasing gross efficiency. It has been shown to improve power output during a 10-16km TT performance on average by 3-6%. Then we have good old caffeine that works via a central mechanism. It’s tried and tested and capable of improving performance to a similar degree as beetroot juice. So in theory we could see a 6-12% improvement in cycling performance? Well we tried this and I wont disclose the results just yet, that’s another story.

One more interesting observation that has been tested in the laboratory and proven to work is the use of music to enhance performance. These days its common to see pros warming up listing to what ever it is that gets them pumped up. But what is this pumped up mechanism and how does it work? Once again its simply a central stimulant. The brain in all its complexity sends commands to the muscle. If we can ‘make the brain happy’ by activating reward centres that are integrated with the motor cortex that drives the muscles then we can drive the muscles harder. Ultimately it’s like having a more powerful battery driving the engine.

So where does peak performance lay? Once we have adapted to training and prepared our physiology for optimal performance we must then ensure our race day protocol maximises our physiologies full potential. Optimisation of the performance of the central component through motivation, and the possible use of centrally acting ergogenic aids is step one. Then, giving the muscle every chance of functioning to its full potential by making sure it has adequate fuel for contraction and the biochemical capacity to contract as efficiently as possible while maintaining homeostatic balance.

Now.. get out there, there is a race to be won…

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