Tennis Fitness: Detraining,
Retraining and Maintenance
By Roy Stevenson

If you skip a few days of training, will the break negatively affect your tennis fitness level?

Dedicated tennis players spend between 5 and 10 hours training each week, including games, skills practice, and general fitness workouts like resistance training, stretching and aerobic fitness.

We all go through downtimes when we're forced cease training and practice due to illness, injury, or travel. And we all notice when we return to the court, our tennis fitness is significantly reduced and that it takes a long time to get back to our former training and competition levels.

What Research Tells Us about what happens with our tennis fitness when we detrain and then retrain:

First, some definitions.

Detraining is the partial or complete loss of training-induced fitness when we stop training or decrease our training load.

Retraining is recovery of our fitness after a period of inactivity.

Should we fret about how much hard-earned fitness we’ve lost, and need we be concerned about a long hard slog we face to regain our tennis fitness. The good news is that a few days of rest or inactivity will not impair our performance at all. In fact, research shows that a few days off actually improves performance as the muscle tissue recovers, rebuilds, and stores more glycogen--its primary fuel.

The bad news is that there’s a point where aerobic fitness and performance decreases with inactivity—it only takes about two to three weeks for the rot to set in. And tennis fitness relies heavily on aerobic fitness for the player to be able to sustain a high level of movement about the court. The higher the level of competition you play in, the more your performance will be negatively impacted by a lay off.

Let’s start with the heart, as that’s the engine driving our aerobic performance. Changes to the heart from detraining are rapid and dramatic; the heart walls experience a significant decrease in thickness, and their left ventricles become smaller. This causes a lower amount of blood ejected with each heartbeat—only 4 to 7 days after stopping training. These changes that take months and even years to develop are undone in just days.

Equally as dramatic are the associated reductions in our maximal oxygen uptake (or our ability to process oxygen). Also known as VO2 max. maximal oxygen uptake is the best indicator of an athlete’s ability to process oxygen, and therefore his or her aerobic fitness. Consider these facts: after 2-3 weeks of detraining, our VO2 max. decreases by 4%.

Your decline in V02 max will vary according to how sedentary you are during your layoff, and how long you have stopped working out. If you are on an active vacation that involves lots of walking or hiking, your losses will not be as significant as if you were completely bedridden with illness.

In one study, female track athletes experienced a 15% drop in VO2 max after a three-month layoff at the end of their season, returning their VO2 max figures back to their original untrained state. Players lose their tennis fitness at a slower rate as their aerobic fitness is lower than that of the runner’s.

But you’re much worse off if completely sedentary. A well-conducted study that confined its subjects to 20 days in bed, found that completely bed-ridden people lost their aerobic fitness (a staggering 27%) faster than if they had ceased training, but remained active.

In addition, your sub maximal heart rate (the rate that your heart beats during a tennis match) declines after 20 days bed rest, and the amount of blood ejected from your ventricles declines 25%. So your ability to move oxygenated blood around your body is reduced by this much. And if you’re an elite tennis player, the VO2 max of very fit athletes declines more and faster than less fit sportspeople.

As if this isn’t disheartening enough, your blood volume and plasma volume decreases by 9% after 2-4 weeks, further contributing to the declining VO2 max figures. The capillaries in your muscles decrease, and the mitochondria (small organelles that process fat and glycogen for our muscles to burn) are reduced in number too.

What about your muscle fuel levels? Glycogen—the carbohydrate fuel stored in muscle cells and liver—the life-blood for athletes—decreases by over 40% after 4 weeks of ceasing your tennis. The enzymes that help glycogen and fats burn during exercise also decline in number after 15 days, as they’re just not needed anymore, according to one study. If you have stopped exercising completely, the percentage of your slow twitch (endurance) muscle fibers may also have reduced in number, according to some studies.

How long will you have to spend retraining to regain your level of tennis fitness?

Clearly, fitter tennis players face a steeper uphill battle to regain fitness compared with less conditioned players. Highly trained athletes experience larger losses in VO2 max and thus it also takes them longer to regain this fitness. Thus, despite the prevailing myth that many athletes believe the fitter you are, the quicker you’ll recover your fitness, research shows quite the opposite. Prior training does not influence regaining your previous fitness level.

The dramatic drop off in physiological parameters points to how critical it is that you never stop training entirely, even in the off-season, because it takes so much longer to get your fitness back. Someone who’s been sick for 3 months, for example, could take up to 6 months to get back to where they were. Also if you’re older, there is some evidence to show it takes longer to retrain as you age past 40.

Maintenance of Training

What if you were able to squeeze some training into your holiday? As we’ve established, stopping training completely shows dramatic reductions in aerobic fitness. Reduced training, however, shows almost no reductions in aerobic fitness for periods of 1-15 weeks, if it’s done the right way.

Reduction of Frequency of Training

If frequency of training is reduced from 3 days/week to one day/week, it tends to slow, but not totally prevent a decline in VO2 max. One study found only a 7% decline in aerobic fitness following this reduction in training.

So if you’re able to train during your vacation, slightly reducing the number of your workouts will help you retain your tennis fitness. But what if you don’t have the time to train frequently while on vacation due to travel schedules, sightseeing, fatigue, long hours on the hoof, etc.

Reduction of Duration of Training

What about cutting back on the length of your training workouts? One study gives us insight into what happens when we shorten our workouts while on vacation—and it’s not all bad news. Research shows that reducing training time by half, maintains almost all VO2 max and performances for 15 weeks.

So if you’re able to do some aerobic workouts every day, even if for a shorter time than usual, will not impact your fitness adversely. But, again, you may not have the opportunity or will to train with your usual frequency, while traveling, despite reduced time in each session.

Reduction of Intensity of Training

The real key to maintaining your hard earned tennis fitness when on vacation with limited training time is intensity. When frequency and duration of training are reduced by as much as 2/3 and intensity of training remains unchanged, VO2 max can be maintained for 15 weeks.

Thus, you must exercise harder to maintain your aerobic fitness when faced with reduced frequency and duration. You can maintain your fitness just by doing one or two short, high intensity running sessions each week. But they’d have to be hard workouts--somewhere around 70% of VO2 max, or approximately 75% of maximal heart rate, if you use a heart rate monitor.

So when on holiday, if the frequency of your workouts is limited by travel, hit the road or treadmill hard for 20-30 minutes each session, or slip in a couple of high intensity interval type workouts each week.

What about losses in skill level for tennis players? This area has been notoriously understudied, as there are so many intangible factors that are difficult to measure. There will certainly be a reduction in skill level, however I suspect that the skills will return quickly with consistent practice once the player starts again. Neuromuscular skills, once gained, tend to stay etched as motor engrams in our memory, and they are recovered quickly with practice. Maintaining base aerobic fitness should be the primary concern of the tennis player who has been sidelined for a period of days, weeks, or especially months.

Clearly, athletes should never stop training completely if they want to retain their aerobic fitness (unless sick or injured). The training effect is, unfortunately, transient, and reversible when we have layoffs from training, even if we’ve been working out for years.

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