The science behind the program

What each study found, in one line, and where it shows up in the program.

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.

   18 studies, 318 players: fatigue had a moderate negative effect on physical fitness (measured mostly as jump height and strength; sprint and agility in single studies) and a small one on stroke performance. The elite/sub-elite difference was significant only for physiological measures.

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.

   Three weeks of multidirectional sprints improved change of direction, reactive agility and short sprints; a random route improved reactive agility more than a known one (19 players).

3. Kong R. et al. (2025). The chronic effects of change of direction during repeated-sprint training on jumping, sprinting, and change-of-direction abilities in players: a systematic review and meta-analysis. PeerJ 13.

   15 trials, 223 players: repeated sprints with changes of direction improved jump, 20–40 m sprint and change of direction; several changes per rep gave the larger gains in sprint and change of direction.

4. Zhou Y. et al. (2025). Effects of neuromuscular training on tennis players: a systematic review and meta-analysis. BMC Sports Science, Medicine and Rehabilitation 17.

   Strength and jump training in tennis players improves strength, power, sprint and agility.

5. de Villarreal E. S. et al. (2009). Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis. Journal of Strength and Conditioning Research 23(2).

   56 studies: the largest jump-height gains came with programs longer than 10 weeks and 20 sessions, using more than 50 jumps a session and a mix of jump types.

6. Van Hooren B., Peake J. M. (2018). Do we need a cool-down after exercise? A narrative review of the psychophysiological effects and the effects on performance, injuries and the long-term adaptive response. Sports Medicine 48(7).

   An active cool-down is largely ineffective for same-day and next-day performance, does not appear to prevent injuries and mostly does not reduce soreness; whether it prevents light-headedness after exercise is unknown.

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).

   Under 4 weeks of too little training, aerobic fitness and endurance performance drop quickly in trained athletes (more moderately in recently trained people); strength declines are limited.

8. Davey P. R., Thorpe R. D., Williams C. (2002). Fatigue decreases skilled tennis performance. Journal of Sports Sciences 20(4).

   18 county-level players hit to exhaustion in an intermittent tennis test (about 35 minutes): groundstroke accuracy fell by 69%, service accuracy to the right court by 30%.

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 expert and 10 novice players: high-intensity fatigue lowered passing accuracy in both groups, but much less steeply in the experts.

10. Tomlin D. L., Wenger H. A. (2001). The relationship between aerobic fitness and recovery from high intensity intermittent exercise. Sports Medicine 31(1).

    Most studies suggest that endurance training or a higher VO2max gives better power recovery across repeated bouts of high-intensity exercise.

11. Roger Federer, Dartmouth commencement address, 9 June 2024.

    Of 1,526 singles matches he won almost 80%, while winning 54% of the points he played.