Guide To Leggings

An extended version of this guide first appeared on the 'StyleLife' blog.

Yoga pose in blue leggings

Leggings have been around (seemingly) forever, over time transcending their 'utility' status to a must-have fashion item. Once worn by a relatively small fitness niche, they became mainstream during the ‘big hair and leg-warmers’ 80s fashion craze and, although their popularity dipped for a few years afterwards, they’ve grown once more to cement their position as a staple. Now, with more styles, colors and fabric choices than you could shake a yoga mat at, a distinctive style can generate as many Instagram comments as kittens and the Kardashians.

Although single colors remain popular, every pattern and image can now be found adorning legs busily engaged in squatting, bending, running and twisting into every conceivable contortion, as well as those simply curled up on a comfy sofa.

If the styles and patterns are mind-boggling in their variety, so too is the choice of material behind the leggings. Most of the famous athletics/athleisure clothing companies have their own ranges, often with impressive-sounding materials which, when delved into, are mostly either nylon or polyester with lycra added for stretch and perhaps a wicking element. The stretch is needed for obvious reasons (we’ll come back to ‘squat-proof’ a little later), and wicking because both nylon and polyester are fossil-fuel derived, and as we all know, oil and water don’t mix.


Polyester and nylon have some different properties, but rather than get bogged down in technical comparisons of a hydrophobic and oleolphilic nature – two terms to look up if you really want more information! – let's keep it simple here and concentrate just on polyester, which is the most popular leggings material. Being derived from oil means that polyester doesn’t readily absorb moisture, which is a problem for fitness attire as keeping fit often means working up a sweat. In relation to clothing, 'wicking' simply means moving moisture from the body to the outside air via the clothing material. On first impressions, not absorbing sweat might sound like a good idea as it suggests no sweat patches or smelly clothes, but in practice it means that any moisture produced by the skin in order to cool down, stays trapped between the skin and the fabric. This is why some polyester, especially when cheaply produced, can feel clammy to wear, almost like a diver’s wet suit.

Wicking is the term to describe how material transfers moisture to the outside air in a similar way to a natural fibre, like cotton.
Clothing made of natural fabrics like cotton will wick, allowing sweat to evaporate. Unfortunately, when it comes to leggings with their stretch and shape retention requirements, cotton isn’t a great choice by itself, which is why it's often mixed with lycra. Baggier sweatpants (note the name) and joggers are a different story, but not shape-hugging leggings.


A key feature many look for in leggings is that they’re ‘squat-proof’, which generally means they a) don’t become semi-transparent when stretched and b) have strong enough seams to not tear apart at what would be an embarrassing point in an exercise routine!

Before we look at these two points in more detail, it’s worth mentioning that leggings need to be the correct size. This sounds obvious, but most clothing isn’t very stretchy and therefore we’re more likely to wear the size that best fits. However, because leggings do stretch (and, let’s face it, many of us like to wear a smaller size if we can get away with it – there’s an ego or self-image thing going on here!), they can often accommodate a size larger than they’re made for. This isn’t a good idea. The amount of ‘give’ that is built into leggings is there to accommodate stretch activities like squatting. If this is already being taken up by simply squeezing into them, there’s no further stretch available and, when the squat happens and something needs to ‘give’, there’s a problem.

Leggings will contract to a small size, so, if in doubt, size up. Leggings one size larger than they need to be will fit, look and perform much better than those one size smaller!

Now, back to the two squat-proof points we mentioned earlier. Taking point a), semi-transparent can be a genuine issue if sheer fabrics are used, but good leggings are made from material that isn’t see-through (which is one reason why polyester is more popular than nylon, which when thin can be sheer), so that’s typically not what’s happening. Far more often, what is mistakenly regarded as semi-transparent isn’t actually the case, and isn’t a real problem, just a lack of understanding on behalf of the observer. To clear this up, we need a quick look at how leggings material is colored or printed.

Some material is dyed or dipped, which means that both sides of the fabric will contain color. Dyed material is less likely to appear semi-transparent when stretched, because the dye penetrates into all parts of the fabric strands, so even when stretched the bits you see are colored. Unfortunately, dyeing can have its downsides. Dye can run. As some dye is in contact with the skin, when we become hot and sweaty some of this dye can lift and transfer to the skin. Dye isn't great for patterns. Also, more dye than is actually needed is used if the hidden, inside part of the clothing is being colored, which is wasteful. Finally, although much has been done to clean up dyes, they have been (and, very often still are) environmentally unfriendly, requiring a lot of clean water and resulting in a lot of chemically-heavy dyed water.

A second method of printing material is called ‘sublimation’ and without getting too technical, this printing process transfers the design and colors to heated pressurised cloth. With the pressure and heat, the print transforms into a gas (or is ‘sublimated’) and is then absorbed by the material. This method has many advantages, including vivid hi-definition designs, less waste, no color run and is more environmentally friendly. In this method, only one side of the material is printed, so the side of the fabric which is against the skin isn’t colored but remains in its base-white state. This means that when stretched, some of the base white is likely to be seen.

Once this is understood, it becomes obvious that the material isn’t semi-transparent, it’s simply that the base color beneath the sublimation printing is showing. Sublimation leggings are as squat-proof as any that are dyed (the material itself might well be the same), but they will take on a whitish sheen when stretched.

Indeed, those ‘in the know’ will often look for this white sheen of sublimation garments as a sign of quality because they’ll be aware of the printing method. Many find that this whitish sheen adds another dimension to the finish, producing different shades, whereas dyed can appear ‘flat’.

Model in blue leggingsNotice how on this single blue design there is a lighter sheen at points where the material is stretched. This is the white base-color of the fabric. In no way are these leggings semi-transparent, but a lack of understanding might lead someone to incorrectly suggest they’re not squat-proof. All sublimated leggings will appear lighter at stretch points. Sublimation printing can be done as the final stage of manufacturing, with garments that are already made – whether leggings, t-shirts, hoodies etc – or it can be done earlier in the process with material that hasn’t yet been made into the finished garment. The former is cheaper and less satisfactory as any creases, slight folds or seamed areas won’t be fully printed, and such folds are inevitable once garments have been sewn together. The latter method is the more expensive of the two and is usually referred to as ‘cut and sew’, because the printing takes place before the material is cut and sewn into the finished product. This results in full printing coverage of the outside of the garment and is the method used by DSent and Dark Sentinel.

The second aspect to being squat-proof is having seams that can take the strain. There are various ‘seamless’ styles available in the athleisure market but the more performance-oriented offerings are overlock and cover stitched, sometimes double stitched. There is a trade-off here between leggings with seamless patterns which might not withstand repeated strenuous workouts and leggings that look and perform like they mean business. The fact is, in serious exercise clothing some stitching will be visible. Where it appears most will obviously depend on the style and seam position of the garment but most often vertical stitching will be clearly seen at the front (crotch area) and back (up the centre of the bottom) and, with high waistband leggings, horizontally where the waistband joins the legs and, depending on the design, vertically at back or sides. Seams up the leg sides (inner or outer depending on design) are likely to be hidden inside the clothing and therefore less visible, although the white base-color of the material will be visible at the point of stitching on darker leggings.

Leggings construction

Top left of image shows inside stitching and the white base color of sublimated leggings. Top right shows clearly visible stitching up the crotch and on the high waistband. Bottom half of image shows white base color showing at stitch points. This is unavoidable with sublimated printing.


In summary, if you intend to put your leggings to the test in working out rather than just relaxing in them, look to strike a balance between those that simply look good and those that are built to perform. Of course, you’ll also expect ethical production, so this is likely to mean:

- a strong polyester-mix of fabrics for stretch and wicking properties;
- sublimated printing, preferably of the cut-and-sew type;
- robust stitching in all the right places;
- carefully sourced materials and accredited manufacturing.

Finally, wear the right size and, if in doubt, size up – we can fool ourselves by squeezing into stretchy leggings, but we won’t fool anybody else when we try to bend or stretch in them!

Squat-proof leggings

1 comment

  • Sally M

    This is so helpful, thanks! The ‘squat-proof’ issue is one often discussed at my gym but that none of us properly understood as it clearly wasn’t that the material was becoming transparent, just taking on a white hue. Now I know why!

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