Modern junior tennis is built on staged equipment. The ball is slowed and the court is shrunk so a child can rally, decide and move like a tennis player instead of chasing bounces above their head.
The four stages
- Red (Stage 3) — 75% slower than a yellow ball, foam or low-compression felt, 8–9 cm diameter. Court 10.97 x 5.48 m, net 80 cm. Typically ages 5–8.
- Orange (Stage 2) — 50% slower, standard size. Court 18 x 6.5 m, net 80 cm. Typically ages 8–10.
- Green (Stage 1) — 25% slower, standard size. Full court, standard net. Typically ages 9–11, and a useful teaching ball for adult beginners.
- Yellow (Stage 0) — the full-pressure ball, full court.
Why slower balls build better players
A slower ball bounces lower and travels less far, so it stays inside a child's strike zone between hip and shoulder. That means real swings, real contact points and real footwork patterns rather than defensive scoops. It also means longer rallies — and rally count is the strongest predictor of whether a child keeps playing.
Beyond juniors
Yellow balls are not all identical either. Pressurised balls come alive out of the can and go dead in a few hours of hard hitting. Pressureless balls feel heavier at first and last far longer, which makes them useful for ball machines and club baskets. Some manufacturers also sell high-altitude balls with lower internal pressure, and extra-duty felt for hard courts versus regular-duty for clay and indoor.
Knowing when to move up
Move a player up when they can consistently rally 10 or more balls, serve to the correct box, and finish points with intent at the current stage — not when they turn a certain age. Pushing a player up early usually produces shorter swings, a defensive contact point and a serve built on effort rather than technique. Coming back down a stage for a block of training is a legitimate coaching tool at any level.