A football shirt looks like a simple thing: a polyester top with a crest on it. It is not. The garments worn in the top flight today are engineered products, with the yarn, the knit structure, the seam placement and the fit all designed around how a body behaves during ninety minutes of running. Most of that engineering is invisible to the supporter in the stands, so this article opens it up. What are modern premier league shirts actually made of, how do they manage heat and sweat, and why does the version sold to fans behave differently from the one worn on the pitch?
From cotton to polyester
Until the 1970s players wore cotton, which is comfortable when dry and miserable when wet: it absorbs sweat, gets heavy and stays that way. Polyester arrived in the late 1970s and dominated by the 1990s because it does the opposite. Its fibres are hydrophobic, meaning they do not soak up water, so moisture sits on the surface and can be moved away. Every Premier League shirt today is polyester, but the differences between a cheap shirt and an elite one lie in how that polyester is spun, knitted and finished.
Recycled yarn and textile waste
Nearly all modern kits are made from recycled polyester. The usual source is plastic bottles, shredded into flakes, melted and extruded into fibre. The more interesting development is fabric made from textile waste rather than bottles. Nike’s Aero-FIT material, introduced on the England kits for the 2026 World Cup and now on club shirts, is made entirely from textile waste in its match version, with a standard Dri-FIT fabric for the stadium version sold to supporters. adidas markets its equivalent as Climacool+, and Puma uses ULTRAWEAVE for player shirts and RE:FIBRE, made from recycled textiles, for replicas.
How a shirt manages sweat
The word every manufacturer uses is “wicking”. It describes capillary action: the fabric is knitted with fine channels that pull moisture from the skin to the outer surface, where the larger area allows it to evaporate. Evaporation is what cools the body, so a shirt that spreads sweat across its surface cools the player more efficiently than one that lets it pool.
Some fabrics add a hydrophilic finish to the outside of the yarn, so the surface attracts water even though the core repels it. That combination, water-hating inside and water-loving outside, is what allows a shirt to feel dry on the skin while visibly damp on the surface.
Ventilation zones and knit structure
Look closely at a player-issue shirt and you will see that the fabric is not uniform. Areas of open mesh sit under the arms, down the sides and across the upper back, where heat builds fastest. Denser knit is used on the chest and shoulders, where the crest and sponsor need a stable surface. This is called body mapping, and it is done at the knitting stage rather than by sewing panels together, which is why modern shirts have fewer seams than they did twenty years ago.
The newest fabrics go further. Aero-FIT uses a highly textured knit that lifts the fabric slightly off the skin, allowing air to circulate in the gap. Nike claims more than double the airflow of its previous materials. It was designed with the heat of a North American summer in mind, and it is now standard on the shirts of Chelsea and other Nike clubs.
Why the player version fits differently
The shirt sold in the club shop is not the shirt worn on the pitch. The player or “authentic” version is cut close to the body, with stretch panels and a shorter body length, because a loose shirt flaps, catches wind and can be grabbed. It is also thinner and lighter, around a third lighter in some cases, because every gram matters over ninety minutes and because the elite fabric is expensive to produce.
The replica is cut for a supporter who will wear it over a T-shirt, sit down in it and put it through a washing machine every week. It uses a heavier interlock knit that holds its shape, a more forgiving fit, and an embroidered or woven crest rather than the heat-bonded one used on the pitch. Neither is better; they are built for different jobs.
Crests, sponsors and weight
On a player shirt, the crest and sponsor are heat-bonded transfers, chosen because they weigh almost nothing and do not restrict the fabric’s stretch. On a replica, the crest is usually embroidered, which supporters prefer because it feels premium and lasts. An embroidered crest can weigh more than the sleeve it sits beside. Manufacturers have experimented with silicone badges and woven jacquard crests, the latter appearing on Chelsea’s 2026/27 shirt, where the entire crest is woven into the fabric as a tonal pattern.
Seams, stitching and durability
Elite shirts use bonded or flatlock seams, which lie flat against the skin and do not chafe. Cheaper shirts use overlocked seams, which are stronger but bulkier. For the supporter, the practical difference is in the wash: bonded seams and heat-bonded prints degrade if washed hot, so manufacturers recommend 30 degrees and no tumble drying. A shirt that has gone bobbly or lost its sponsor has usually been washed like a bath towel.
Colour, dye and why cheap shirts fade
Polyester cannot be dyed the way cotton is. The fibre does not absorb water-based dye, so manufacturers use disperse dyes applied at high temperature and pressure, which force the colour into the fibre itself. Done properly, the colour is locked in and will survive a season of washing and sunlight. Done cheaply, the dye sits closer to the surface and fades within months, which is why a low-cost shirt in a strong colour, red especially, often looks tired by Christmas while the official version does not.
Patterns are added by sublimation, where the design is printed on paper and transferred to the fabric with heat, turning the ink to gas so it bonds with the polyester. A sublimated pattern cannot crack or peel, because it is part of the fibre. A heat-transfer print, the cheaper method, sits on top of the fabric as a layer and eventually lifts. If a shirt’s pattern feels like a layer under your thumb, that is what it is.
What all this means for the supporter
The science explains the price gap. A player-issue shirt costs £110 to £125 because the fabric, the knit and the construction are expensive, and because the club’s kit contract has to be paid for. A replica costs £80 to £90 because it uses a simpler fabric and a simpler build. A cheap fan-version shirt from an independent seller costs a fraction of either because it uses a basic polyester knit with a printed crest.
For a player, those differences matter. For a supporter in a seat, the shirt’s job is to look right, fit well and last the season, and a well-made basic polyester shirt does that perfectly well. The engineering is impressive; it is also, for most people, unnecessary. For more on how kits are designed, made and marketed, explore the Kit section on Science & Football.