Tonight, thousands of us will wake up in the early hours to support our boys in black as they face South Africa in the semifinals of the Rugby World Cup. What you may not realise is how much science and technology surrounds that silver fern as the All Blacks wear their most technically advanced rugby jersey to date.
Originally long sleeved, blue with a gold fern and made from heavy wool, the All Blacks jersey has been through many iterations over the last century. Traditionally based on a one-jersey-fits-all style, this year there are two styles of jersey within the team. The backs will wear the standard figure-hugging jerseys we have seen over the last few years. The forwards have a baggier jersey with raised seams down the sides, enabling them to grab each other to help prevent the scrum from collapsing.
Sonny Bill Williams' famous ripped sleeve in the opening game of the last World Cup was found to be caused by a stud puncturing and ripping the fabric in the old jersey, meaning strength was a priority for this year's design. Carbon fibre had already been used in the Americas Cup boats and the Boeing 787 aircraft because of its amazing strength-to-weight ratio, which made it an ideal candidate to reinforce a lightweight rip-resistant rugby jersey. Woven from a technical fabric originally designed for space missions, the secret carbon filament ingredient in this year's jersey gives it unique properties.
The main requirement was to pass stringent mechanical tests, including being tough enough to handle stud impact and stud drag forces while being soft and light enough to feel comfortable on the skin. By weaving carbon fibre into the main fabric, the strength was increased and the carbon absorbs visible light wavelengths, resulting in the blackest looking All Blacks jersey to date. The one drawback of carbon fibre is that it absorbs fluid, so a special chemical had to be coated on to the fibres to help wick moisture away from the skin. This allows the sweat to evaporate, keeping the players cool and dry.
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The tight fit was designed to make it behave as if the players were wearing a second skin. To achieve this scientists first had to understand how skin behaved under different conditions. Dots were painted directly on to the players while cameras recorded and tracked how each dot moved relative to the other dots as a function of each rugby manoeuvre.
This data was then converted into quantitative strain measurements using dynamic stretch analysis which calculated the amount and direction of stretching the skin goes through at any point on the torso. The research discovered that the skin moved most in the horizontal direction along the sides and backs of the players as they stretched their bodies out to reach for the ball or move in for a tackle.
The conclusion was that the perfect jersey needed to be woven with anisotropic properties, meaning that it stretched more in the horizontal direction for greater flexibility but was stiffer in the vertical direction to prevent the jersey riding up.
You can rest assured that scientific research and innovation has resulted in our boys wearing the strongest, lightest, most technical All Blacks jersey ever made.
Dr Michelle Dickinson, also known as Nanogirl, is an Auckland University nanotechnologist who is passionate about getting Kiwis hooked on science. Tweet her your science questions @medickinson