Does this look familiar (<-)? It's the sight of a run-of-the-mill junior tennis player immediately before the match. If you've been around junior events long enough you will learn to spot the mummies - they are usually wearing track suits, hands straight by the sides, walking aimlessly with stiff legs from bag to tournament desk to bathroom and back. Sometimes they are chatting with their friends although it;s usually in monosylabic grunts. I've always wondered why it is that some kids get so...cold immediately before the match. Why are they shivering so much?! Did the temperature suddenly drop after exiting the car? Weird...
It turns out that shivers are actually reflexes - controlled by the nervous system - produced automatically by the body to keep us safe. When your body temperature drops below a certain level - say 98° - your nerves send a signals saying "I'm cold". What happens next is that your muscles contract and loosen really fast (causing friction which increases body heat slightly) causing you to shiver. What does this have to do with tennis? Researchers have conducted many tests on lab animals to see how their body temperature changes with fear. In these lab experiments, scientists use infra-red thermography to get images in skin temperatures to see the animals' response to a fear agent. What they have generally found is that the animals usually froze into immobility with a significant drop in skin temperature. It's the same with people faced with fear, anxiety and nerves - although some may experience a rise in body temperature a lot of players will experience a drop in body temperature; their feet and hands become cold; body trembles. For some players, muscle tension will increase and breathing will become shallow (i.e., less oxygen entering the system) and labored.
In a match, this usually translates into 3-4 poor first games. But here's the kicker: rather than doing something productive to keep warm and "stay loose", some of these player will continue to walk around stiffly all bundled up in their track suits. I never understood why these players - if they care about the outcome in the first place - don't engage in some productive exercises to warm-up and "shake off" the anxiety. Jog in place, jump rope, run some sprints, play some practice points...anything to keep the blood flowing to the limbs and oxygen entering the system. Perhaps nobody told them regarding the physiological importance of "being limber". Warming up is not just important for the strokes but also for the body...the heart, the lungs, the muscles, the eyes, etc. As a player, it's important to enter the tennis court "firing on all pistons". If you wait 3-4 games to find a way to settle down, it may already be too late. As you get older, "comebacks" from 3-4 games down will be much more rare. Therefore, if you're the type who freezes under pressure, find a way to stay loose and limber. Start setting warm-up rituals early. All the "great players" hame them (I bet that even Nadal's pre-match sprint is a last second way to burn off some extra nervousness. And his jumping and running in the locker-room before the match is legendary).
Initially, it's better if you (junior player) get on the court sweaty (and perhaps a little tired) than "not warmed up at all". At least you're ready to pounce on the ball from the word "GO!" As you get older and more experienced, you will be able to fine-tune your warm-up rituals to suit your needs and energy levels. But don't wait until the start of the match to do something that could have been addressed without a racket.