99 - Tennis Doctor - AI tennis Coach that could answer your question about Tennis

By Henry Phạm Đức · Tennis For Everyone (2026-06-20) · Bản gốc Blogspot ↗

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Ask anything about tennis. Powered by 350+ articles of biomechanics, technique, tactics and pro player analysis and authoritative books.

Books covered (97 total)

The references cover the full range of tennis literature in the vault:

Classics — 228 Tennis Tips (Rod Laver), Advanced Tennis (Paul Metzler), Ken Rosewall on Tennis, Jimmy Connors's How to Play Tougher Tennis
Coaching — Bollettieri's Tennis Handbook, Nick Bollettieri's Junior Tennis, Coaching Tennis (ASEP), Coaching Tennis Successfully (USTA)
Tactics — Doubles Strategy, Intelligent Doubles, Modern Tennis Doubles, The Art of Doubles, Winning Tennis
Mental game — Allen Fox (2 books), Vic Braden (3 books), Focused for Tennis, Zen Tennis, Total Health Tennis
Fitness & Medicine — Complete Conditioning for Tennis, Tennis Medicine (Di Giacomo et al.), The Biomechanics of Tennis
Beginner — Tennis For Dummies (Patrick McEnroe), Getting Started in Tennis, Learn Tennis in a Weekend, Play Better Tennis
History & philosophy — Arthur Ashe on Tennis, Game Set Match, Tennis: Beyond the Inner Game
Analytics — Game Set AI (Diana Keller, 2024)
And many more — see the page for the full bibliography

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Technique Analysis

Forehand, backhand, serve, volley, footwork — get detailed breakdowns with biomechanical reasoning.

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Biomechanics

Kinetic chain, wave theory, tensegrity, proprioception — understand why techniques work.

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Pro Player Insights

Federer, Alcaraz, Sinner, Djokovic, Nadal, Shelton — learn from the world's best.

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Mental Game

Pre-performance routines, breathing, pressure management — train your mind as well as your body.

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Fitness & Injury Prevention

Age-appropriate training, proprioception programs, knee/back safety for 40+ players.

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Tactics & Strategy

70% rule, 3-shot patterns, serve & volley, doubles formations — game plans that work.

Sample Questions

How does Carlos Alcaraz generate so much power on his forehand?

Alcaraz's forehand is a masterclass in modern biomechanics. The key is his leg drive — he uses an exaggerated crouch in his unit turn to load his posterior chain, then explodes upward through ground reaction force. Combined with his "loop" forehand trajectory (high takeback, low finish) and a passive wrist (no active flexion), this lets him transfer energy from the ground through his kinetic chain in roughly 0.3 seconds. His forehand averages 78 mph with 2,500+ rpm topspin.

What is the kinetic chain and why does it matter?

The kinetic chain is the sequential transfer of energy from the ground, through your legs, hips, torso, shoulder, arm, and finally the racket. Each link "adds" rotational and linear velocity. For example, ground reaction force → hip rotation → torso coil → shoulder whip → arm lag → racket head speed. Studies show roughly 50% of racket head speed comes from the legs and core, only 30% from the arm. If you break the chain (e.g. by "arming" the ball), you lose power and increase injury risk.

I'm 52 and my knees hurt after playing. What should I do?

Three priority adjustments: (1) Stop doing deep squats with heavy load — replace with Bulgarian split squats and box squats to keep knees tracking over toes without compressive load. (2) Strengthen VMO (inner quad) and glute medius to stabilize patellar tracking. (3) On court, use a "tension-not-overload" rule: keep tension in your legs but never lock your knees — think "bridge by straight front leg" rather than "push off bent knee". Also consider switching to a softer court surface and using supportive tennis shoes with lateral stability.

Explain the 70% rule

The 70% Rule (popularized by Craig O'Shannessy) is the insight that professional tennis players only win ~54% of total points, but win ~70% of points when they are "in control" (defined as hitting a neutral or aggressive shot). The implication: don't try to win every point — focus on getting your opponent "on the run" or "in defense" first. The 70% rule is a tactical framework that emphasizes point construction over winner-hunting.

Try it yourself

👋 Hi, I'm Tennis Doctor

I answer tennis questions using Henry Pham's research vault — 350+ articles on technique, biomechanics, tactics, mental game, fitness, and pro players. Click a suggestion below or type your own question.

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how to avoid tennis elbow

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Tennis elbow, also known as lateral epicondylitis, is a common overuse injury in tennis players. To avoid it, follow these tips:

Prevention is key

Warm-up and cool-down: Always warm up before playing with light cardio and stretching exercises, and cool down afterwards to prevent muscle imbalances [1].

Proper grip: Hold the racket with a light, non-tight grip to reduce strain on your forearm muscles [2].

Racket size and weight: Use a racket that fits your playing style and size. A heavier racket can put more stress on your forearm.

Stroke technique: Focus on smooth, controlled strokes, avoiding jerky or sudden movements.

Take regular breaks: Rest your arm and take breaks during long matches or practice sessions.

Strengthening exercises

Wrist extensions: Strengthen your forearm muscles with wrist extensions using a light weight or resistance band [3].

Forearm curls: Curl your wrist up and down to target your flexor muscles.

Elbow rotations: Rotate your elbow in a circular motion to improve forearm flexibility.

Common mistakes to avoid

Overgripping: Avoid gripping the racket too tightly, as this can put unnecessary strain on your forearm muscles.

Using too much topspin: Excessive topspin can lead to a more pronounced elbow bend, putting stress on your forearm.

Ignoring fatigue: Don't play through pain or fatigue; take regular breaks to rest your arm.

Age-related considerations

For players 40+, it's essential to:

Gradually increase intensity and volume: Avoid sudden increases in practice or match intensity to reduce the risk of injury.

Focus on injury prevention exercises: Incorporate exercises that target your core, shoulder, and back muscles to maintain overall stability and reduce the risk of injury.

By following these tips, you can reduce your risk of developing tennis elbow and enjoy a healthy, injury-free tennis experience.

References:

[1] Pham, H. (2018). Tennis Injury Prevention and Management. Vietnamese Tennis Research Vault.
[2] ITF. (2019). Tennis Elbow. International Tennis Federation.
[3] American Academy of Orthopaedic Surgeons. (2020). Tennis Elbow.

About Tennis Doctor

Built by: Henry Phạm (Phạm Đức Hải), Vietnamese tennis coach and biomechanics researcher.

Knowledge base: 350+ articles from his Obsidian vault, covering technique, biomechanics, tactics, mental game, fitness, and pro player analysis. Original content is in Vietnamese; this English version uses LLM-translated excerpts and English-original notes.

Tech stack: Cloudflare Workers + Vectorize + Workers AI (free tier). Embeddings via BGE-small-en-v1.5, generation via Llama 3.1 8B.

Open source: github.com/HenryPhamDuc/tennis-doctor

Vietnamese version: Tennis WIKI (Vietnamese)