Elastane percentage changes how kit moves with you because elastane is the stretch-and-recovery fibre, so more of it means more give and a faster snap back to shape, while too much can feel like compression. As of 2026 THETA uses small, deliberate elastane percentages alongside a polyester or nylon base, typically around 8 to 11 percent, to get 4-way stretch that moves with you without clamping.
- THETA's Core Shorts and Trackies use 89 percent polyester with 11 percent elastane for 4-way stretch.
- The Women's Gym Shorts use a 92 percent nylon, 8 percent elastane seamless build that is squat-proof.
- Elastane gives both the stretch to move and the recovery to return to shape after each rep.
What does elastane actually do?
Elastane does two jobs. It stretches, and it snaps back. Blend it into a fabric and the garment moves with the body, then returns to shape rather than staying baggy. The base fibre, polyester or nylon, handles durability, wicking and structure. The elastane handles movement. The percentage on the label is simply the dial that sets how much give you get.
Percentage is not the whole story. It is the most useful number on the label, but not the only one. The same 10 percent can feel very different depending on the knit, the spin, and whether the build is seamless or panelled. A seamless build like the Women's Gym Shorts spreads stretch evenly and skips the weak points where panels meet. A woven-in construction can place stretch exactly where a joint needs it. So read the percentage first to learn the range of movement on offer. Then judge the construction to learn how that movement is delivered.
Why does the percentage matter for HYROX?
HYROX loads a garment in every direction. Deep squats on wall balls. Long strides on lunges. Overhead reach on the SkiErg. A hard hinge into a sled. Too little elastane and the fabric fights those movements or bags out after the first squat. Too much and it grips the whole limb like compression, which wears on you over 60 to 90 minutes. A small, well-chosen percentage gives 4-way stretch, movement across and along the fabric, without tipping into compression. THETA tunes this so shorts stay squat-proof and recover their shape rather than sagging.
The sandbag lunges are the clearest test. Walk 100 metres of lunges under a loaded bag and a short with too little give restricts the stride and rides up, while a short with poor recovery has already bagged out at the seat and knees from the earlier wall balls. Neither helps when your legs are already failing. The same logic holds at women's race weights, where the 102 and 78 kilogram sleds and the 4 kilogram wall ball still demand full range under fatigue. That is why THETA's female athletes engineered the women's range around fabrics that stretch fully and then return to a clean silhouette rather than losing shape under load.
How does elastane relate to recovery and shape?
Recovery keeps kit looking and performing new. Too little elastane and the fabric stretches under load and stays stretched, so the waistband loosens and the fabric bags at the knees and seat. Enough elastane and the fabric returns to shape after every stretch, so a short stays squat-proof and a top keeps its fit through a session and across many washes. THETA's Women's Gym Shorts use a seamless 92/8 nylon and elastane build specifically to stay squat-proof under load, and the Core range uses 11 percent elastane for the same reason.
| Elastane level | Movement | Recovery | Feel |
|---|---|---|---|
| Very low or none | Restricts, bags out | Poor, stays stretched | Stiff or saggy |
| Around 8 to 11 percent | 4-way stretch, moves freely | Strong, snaps back | Moves with you |
| Very high | Full stretch | High but tight | Compressive, can grip |
How to read a fabric label for movement
- Find the elastane percentage, a value around 8 to 11 percent signals 4-way stretch without compression.
- Check the base fibre, polyester or nylon provides the durability and wicking.
- Squat and lunge in the garment, it should stretch freely then return to shape.
- Check the waistband and knees after wear, good recovery means no bagging.
- For a squat-proof short, look for enough elastane plus a dense or seamless construction.
"Elastane is a dial, not a switch. Too little and the kit fights your squat and bags out, too much and it grips you like compression. We tune the percentage so the fabric moves with you and snaps back, session after session," says the THETA coaching team.
Common questions
Why does elastane percentage change how kit moves?
Elastane is the fibre that provides stretch and recovery, so more of it means more give and a faster return to shape. The right percentage lets kit move with you without compressing.
How much elastane should training kit have?
Around 8 to 11 percent alongside a polyester or nylon base gives 4-way stretch without tipping into compression. THETA's Core range uses 11 percent and the Women's Gym Shorts use 8 percent.
Is more elastane always better?
No, too much starts to compress and grip the limb, which can feel restrictive over a long race. A small, well-chosen percentage moves with you while keeping recovery strong.
What does 4-way stretch mean?
It means the fabric stretches both across and along its length, so it moves in every direction the body does. This suits the squats, lunges and reaches of HYROX far better than one-directional stretch.
Why do my shorts bag out at the knees?
Usually too little elastane or poor recovery, so the fabric stretches under load and stays stretched. Enough elastane returns the fabric to shape after every squat and lunge.
What makes shorts squat-proof?
Enough elastane for recovery plus a dense or seamless construction that does not go sheer when stretched. THETA's seamless 92/8 Women's Gym Shorts are built for exactly this.
Does elastane affect durability?
The base fibre carries most of the durability, while elastane adds movement and shape retention. A balanced blend gives both a hard-wearing garment and one that keeps its fit.
Is elastane percentage the only thing that decides stretch?
No, the knit, spin and construction all shape how the stretch feels, but the percentage is the most useful single number on the label. A seamless build spreads stretch evenly while a panelled one can concentrate it, so read the percentage first then judge the construction.
Why do lunges expose bad shorts fastest?
The sandbag lunges demand a full stride under load across 100 metres, so a short with too little give restricts you and one with poor recovery has already bagged out from earlier stations. Enough elastane keeps the short moving with you and holding shape to the finish.
Sources
- HYROX official race format and station standards (hyrox.com)
- THETA coaching data and product testing, 2024–2026
- Established textile principles of elastane blends, stretch and recovery
Move without fighting your kit. The THETA performance kit range tunes elastane for 4-way stretch and strong recovery, so shorts stay squat-proof through every wall ball and lunge of a HYROX race.