Almost every adult player I meet at TAG International Tennis Academy tells me the same thing: their strokes feel fine in a lesson, and then they lose the third set to someone with worse technique. In Singapore’s heat and humidity, that is rarely a technical problem. It is a fitness problem wearing a technical disguise.
My sessions are built around high intensity, high repetition and constant movement, and the reason is simple. A stroke you can only produce when you are fresh and balanced is not a stroke you own yet. So before I plan anyone’s training block, I run one test.
The 20-Ball Rally Test
The test is deliberately unglamorous. You and I rally crosscourt from the baseline, at a pace you can sustain, and we try to reach twenty balls in the court. Then we do it again. And again — six rallies with only the time it takes to pick up a ball in between.
There is no scoring, no winners, no target zones. The only instruction is to keep the ball in play and keep your shape. What I am watching is not the ball at all.
What I am actually looking for
- Does the split-step disappear? Under fatigue, the split-step is the first thing players drop. Once it goes, you are reacting late on every ball, and the errors that follow look like bad technique.
- Does the recovery step get lazy? Watch whether a player still recovers towards the middle after ball twelve the way they did after ball three. Most do not.
- Does the contact point drift backwards? Tired legs mean you stop stepping in. The ball gets taken later, the swing gets shorter, and depth collapses.
- Does breathing become audible before rally four? If it does, your aerobic base is the limiting factor, not your forehand.
A player who can hold their structure across all six rallies is match-ready. A player whose rallies get shorter each round — twenty, then fourteen, then nine — has found the real reason they lose third sets.
Why Rally Length Beats a Running Test
Plenty of players are fit in the gym and unfit on court. Tennis fitness is not steady-state running; it is repeated short, sharp efforts with incomplete recovery, performed while making decisions. A rally test measures exactly that combination, on the surface you actually compete on, in the conditions you actually compete in.
It also gives you a number you can chase. Six rallies of twenty is a genuinely useful benchmark for a club-level player in Singapore. Reaching it consistently — not once on a good day — usually takes eight to twelve weeks of structured work.
How I Build the Fitness Back Into the Tennis
I do not send players away to run. I make the tennis harder instead, because that trains the movement patterns and the decision-making together.
- Live-ball only. Basket feeding has its place for a technical fix, but it lets you rest between balls. Live rallies do not.
- Shorter rest, not longer drills. Cutting recovery from 45 seconds to 20 changes a session more than adding ten minutes to it.
- Two-on-one patterns. One player covers the full court against two. It is the most honest conditioning drill in tennis.
- Finish tired, not fresh. The last fifteen minutes of every session are point play, deliberately scheduled when legs are heavy — because that is when matches are decided.
A Note on Cross-Training
I also compete as a professional pickleball player, and players often ask whether pickleball helps their tennis fitness. Honestly: it helps reaction speed and net reflexes far more than it helps endurance. The court is smaller and the rallies are shorter. It is excellent cross-training for the first two metres of your movement and poor substitute for the aerobic base you need in a three-set match. I wrote about that trade-off in more detail in what actually transfers between pickleball and tennis, and players who want dedicated court time can find it through PickleChoo.
Where to Take This Next
If the test exposes your net game rather than your legs — you hold up fine from the baseline but lose the point the moment you move forward — that is a different problem, and Coach Ray Paler, TAG’s serve-and-volley and doubles specialist, is the coach I would point you towards.
If you pass the test comfortably and want to know what the next level of physical standard looks like, train against the competitive end of the TAG network. Coach Bo Alburo reached a career-high ITF Men’s 35+ World No. 2 singles ranking, and Coach XT, who founded TAG, reached ITF Men’s 35+ World No. 56. Hitting with players at that level recalibrates what “working hard” actually means.
Otherwise, book a session and let us run the test. It takes twenty minutes and it will tell you more about your tennis than a month of lessons. Full programme details are on the TAG International tennis lessons page, or call +65 8962 8400.
Coach Vince Geo Serino is a tennis coach with TAG International Tennis Academy in Singapore and a professional pickleball player from the Philippines. He coaches islandwide, including at Winchester Tennis Arena and Chinese Swimming Club.
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