When Should Juniors Switch to Polyester Strings

Key Points

• Age Consideration
  Generally, 15 years or older is when players can start experimenting with polyester strings without concern.
  Under 15 requires more consideration based on play frequency, injury history, and level.
• Key Criteria for Younger Players Transitioning to Poly
  Competitive Level – Must be a performance junior (playing national/state tournaments, among top peers).
  Technical Foundation – Receiving consistent coaching (2–3 times/week) and technically sound.
  Training Load – High training volume increases injury risk, so string choice becomes more critical.
• What Type of Polyester to Use
  Choose soft polyesters with dynamic stiffness under 200 lb/in to minimize arm stress.
  Recommended soft polys:
  → Yonex Poly Tour Air
  → Head Lynx Touch
• Avoid Too-Stiff Strings for Young Players
  Common pro-level polys like Luxilon Alu Power, Babolat RPM Blast, and Yonex Poly Tour Pro have dynamic stiffness around 250 lb/in—too stiff for juniors.
  These can increase injury risk due to more vibration and impact transferred to the body.
• Why It Matters
  Soft polyesters help reduce arm strain, making them more suitable for younger, high-volume players.
  Choosing the right string can help extend development and avoid overuse injuries.