Why you fade in the second set, and what to train

In the first set you can hang with anyone. Then your first step gets late, your shots get rushed and your game resets to factory settings. That is fatigue, and it is trainable.

What fatigue does to a tennis player

A 2025 meta-analysis pooled 18 studies with 318 tennis players.^[1] Fatigue had:

• a moderate negative effect on physical fitness, measured mostly as jump height and strength (sprint and agility in single studies);
• a small negative effect on stroke performance (mostly serve velocity in the studies);
• a large effect on physiological markers such as blood lactate.

Late in a match you jump lower, push off with less force and hit worse. County-level players hitting to exhaustion lost 69% of their groundstroke accuracy and 30% of their service accuracy.^[8]

Fatigue hits the less fit harder

• In the tennis meta-analysis, the same fatiguing protocols strained sub-elite players' physiology (heart rate, lactate) far more than elite players'.^[1]
• Fitter athletes recover power faster between repeated hard efforts: most studies tie better recovery to endurance training and a higher aerobic capacity.^[10]
• Skill buffers fatigue: in basketball, fatigue lowered passing accuracy in experts and novices alike, but much less steeply in the experts.^[9]

That is the club player's opening: the fitter you are, the less of your game the third set takes away.

Why a small edge decides matches

Do the maths: if you lose 10% of your speed by the third set and your opponent loses 20%, you are the stronger player when it counts, even if you were equal in the first.

Tennis scoring magnifies small edges. One of the greatest players ever won 54% of the points he played, and almost 80% of his 1,526 matches.^[11] A few points' edge late in a match is the difference between losing to someone and beating them.

What to train

• Repeated fast efforts with short recovery, the rhythm of points: intervals.
• The split-step and the first step, timed to the opponent's contact: the split-step rally and arrow reaction.
• Change of direction on a random cue: the cone drill; random routes improved reactive agility more than known ones.^[2]
• Leg power and single-leg strength: jumps, bounds, split squats.

Keep it going: fitness fades fast when training stops.^[7] The 6-week program puts all of this in about an hour a week.

Sources

1. Lambrich J., Muehlbauer T. (2025). Effects of fatigue on physiological, physical fitness, and stroke performance related parameters in healthy tennis players: a systematic review and meta-analysis. Frontiers in Sports and Active Living 7.
2. Zhou Z. et al. (2024). The effect of multi-directional sprint training on change-of-direction speed and reactive agility of collegiate tennis players. PeerJ 12.
7. Mujika I., Padilla S. (2000). Detraining: loss of training-induced physiological and performance adaptations. Part I: short term insufficient training stimulus. Sports Medicine 30(2).
8. Davey P. R., Thorpe R. D., Williams C. (2002). Fatigue decreases skilled tennis performance. Journal of Sports Sciences 20(4).
9. Lyons M., Al-Nakeeb Y., Nevill A. (2006). The impact of moderate and high intensity total body fatigue on passing accuracy in expert and novice basketball players. Journal of Sports Science and Medicine 5(2).
10. Tomlin D. L., Wenger H. A. (2001). The relationship between aerobic fitness and recovery from high intensity intermittent exercise. Sports Medicine 31(1).
11. Roger Federer, Dartmouth commencement address, 9 June 2024.