Arena Powerskin ST Next Girls Size Guide

This size guide covers the Arena Powerskin ST Next Girls’ Kneesuit — the next generation of Arena’s iconic ST racing suit and the first ever World Aquatics (FINA) approved racing suit made with recycled fabrics. Made from over 60% recycled fibre from waste yarns, the ST Next delivers sustainable performance without compromise. Features an open-back style with reinforced shoulder straps for comfort.

The new fabric is significantly lighter and faster than its predecessor, absorbing less water and reducing drag for longer-lasting compression and enhanced durability race after race. Designed with low-profile seams for perfect fit and outstanding freedom of movement, plus UV protection (50+ UPF). The perfect tech suit for the next generation of junior swimmers. All measurements are body measurements taken directly from your child’s body. Use the Torso Loop (D) as the primary sizing guide.

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Body Measurement Points
Arena Arena Powerskin ST Next Girls' Kneesuit girls body measurement points — chest, waist, hip and torso loop
How to Measure

Take all measurements directly against your child’s skin using a soft tape measure. Use the Torso Loop (D) as the primary sizing guide — this determines how the suit sits across the shoulders and through the body. Age is shown as a guide only.

  • A
    ChestMeasure around the fullest part of the chest, keeping the tape horizontal and snug but not tight.
  • B
    WaistMeasure at the narrowest part of the natural waist, keeping the tape horizontal.
  • C
    HipMeasure around the fullest, widest part of the hips and seat, keeping the tape horizontal.
  • D
    Torso LoopMeasure over one shoulder, down the front, under the crotch and back up to the same shoulder.

If measurements fall between sizes, speak to a member of staff at Allens who will be happy to advise on the best fit.

Sizing Table — Arena Powerskin ST Next Girls' Kneesuit
Sizing 22 24 26 28
International Size Equivalents
UK 22 / 6–7 yrs 24 / 8–9 yrs 26 / 10–11 yrs 28 / 12–13 yrs
USA 22 24 26 28
France / Italy 6–7 yrs 8–9 yrs 10–11 yrs 12–13 yrs
Germany (height cm) 116 128 140 152
Body Measurements (cm)
A — Chest 58–62 64–68 70–74 76–80
B — Waist 54–56 56–58 58–60 60–62
C — Hip 66–68 70–74 76–80 82–86
D — Torso Loop 110–120 120–125 125–130 130–135

Age ranges are a guide only. All measurements are body measurements, not garment measurements. Use the Torso Loop (D) as the primary sizing guide. Speak to a member of staff at Allens if you are unsure.

Fit Notes — Arena Powerskin ST Next Girls' Kneesuit
  • Always use body measurements to select the correct size — age ranges are a guide only as children develop at very different rates.
  • Use the Torso Loop (D) as the primary sizing guide — this determines how the kneesuit sits across the shoulders and through the body.
  • If measurements fall between sizes, speak to a member of staff at Allens who will be happy to advise on the best fit.
  • The recycled eco-friendly fabric is lighter and faster than the previous ST generation — the suit should feel close-fitting and supportive with excellent freedom of movement throughout a full competition day.
  • The reinforced shoulder straps should sit flat with no pulling or twisting — the open-back design increases upper body freedom of movement during racing.
  • Low-profile seams should lie completely flat against the skin with no rubbing or pressure points — particularly important for younger swimmers in longer events.
  • The 50+ UPF sun protection is built into the fabric — this is preserved by rinsing in cold fresh water after every use and avoiding prolonged direct sunlight when storing.
  • The suit should be completely wrinkle-free when correctly fitted — any bunching or gathering indicates the suit is too large.
  • The shoulder straps should sit flat with no pulling or twisting. Leg hems should end above the knee in line with World Aquatics regulations.
  • Allow 10–15 minutes to put on correctly for the first time. Take care with fingernails and jewellery to protect the fabric.
  • Do not use sunscreen, oils, or petroleum-based products before putting on the suit as these degrade the fabric.
  • Rinse in cold fresh water immediately after each use. Do not machine wash, tumble dry, iron, or dry-clean.
  • Unsure? Contact our team or call +44 1827 330600. Speak to a member of staff at Allens if you are unsure.
Frequently Asked Questions — Arena Powerskin ST Next Girls' Kneesuit

Measure your child’s chest (A), waist (B), hip (C), and torso loop (D) using a soft tape measure directly against the skin. Use the Torso Loop (D) as the primary guide and compare all measurements to the sizing table above. Age is shown as a guide only — always use body measurements as children develop at very different rates. Speak to a member of staff at Allens if you are unsure.

The Torso Loop is measured by running a soft tape measure over one shoulder, down the front of the body, under the crotch, and back up to the same shoulder. This is the most important measurement for a kneesuit as it determines how the suit sits across the shoulders and through the body.

Always select by body measurements. The age ranges shown are a guide only — children develop at very different rates and age alone is not a reliable indicator of the correct size. Measure the chest, waist, hip, and torso loop and compare to the sizing table, using the torso loop as the primary guide.

A junior racing kneesuit should feel firm and compressive but comfortable throughout a full competition day. It should be completely wrinkle-free when correctly fitted — any bunching or gathering indicates the suit is too large. The straps should sit flat on the shoulders with no pulling, and leg hems should end above the knee in line with World Aquatics regulations.

Yes — both the Arena Powerskin Impulso and ST Next Girls’ Kneesuits meet FINA/World Aquatics specifications and are approved for use in all sanctioned competitive swimming events. Always check with your event organiser for any local age group rules regarding tech suits in competition. Speak to a member of staff at Allens if you need further guidance.

If your child’s measurements fall between two sizes, speak to a member of staff at Allens who will be happy to advise on the best fit. Arena racing kneesuits are designed to fit closely — a suit that fits correctly should feel firm and supportive without restricting breathing or movement.

Arena racing kneesuits are competition suits and are not designed for regular training use. Using a tech suit for training will degrade the fabric and reduce its lifespan significantly. Reserve it for races and competition warm-ups. Arena offer a wide range of junior training swimsuits for everyday pool use.

Rinse the suit in cold fresh water immediately after every use. Do not machine wash, tumble dry, iron, or dry-clean. Store flat and dry, away from direct sunlight. Avoid contact with sunscreen, oils, and petroleum-based products. Do not wring or twist the suit. Handle with care when putting on and taking off to protect the fabric.