Materials in sport: Cricket
The 2015 Ashes series has thrilled fans around the world this summer. Rhiannon Garth Jones reports on the materials that contributed along the way.
If you’ve been following the cricket commentary since July, you might be forgiven for thinking that tweaks to the pitches make the only difference that matters. England’s bowlers have proved, time and again, how deadly they can be with the right pitch conditions. But these aren’t the only seemingly minor changes that can have a huge impact. The materials science behind the equipment used in cricket is increasingly important.
Some new cricket bats can set you back around £750, and there’s one main reason for that – the quality of the wood. When bat manufacturers say they are looking for the ‘perfect wood’, they mean truly flawless. Any knot, defect or other blemish – such as unevenly spaced grains – could affect the performance. English willow, with its soft, fibrous timber, is preferred for batting in Test cricket but for training bats many choose Kashmir willow, which is harder and lasts longer, even if it does take a while to ‘wear in’.
Once selected, the timber at the front of the blade has to be flattened and hardened, through a process of machining, grading and pressing. A ‘sweet spot’ is created (and thoroughly regulated, to prevent batsmen from gaining too much of an advantage), which can be adapted to fit the player’s personal technique. Blades made using carbon fibre, aluminium, graphene or anything other than wood have been banned, for providing too much of an advantage to the batter.
The handle is comprised of rubber and cane, the latter often infused with the former, and spliced into the blade flush with the wood, before having rubber grips added. Titanium has been used in recent bat handles, to provide more power in the hitting zone, but this proved so successful that now only 10% of the handle volume can be a material other than cane.
At the lower ends of most ranges, the materials used in cricket gloves haven’t really changed – sections of raw cotton fibres connect to the finger sections of leather or leather-substitute gloves. At the higher end, however, raw cotton is mostly or entirely replaced with high-density foam (HDF) padding, which reduces weight and increases impact absorption. Strong plastics are often inserted to disperse the impact. d3o, a smart fabric, has recently been introduced into one brand of cricket gloves. It has the soft, pliable qualities of rubber but, when impacted, becomes completely rigid to prevent trauma.
Although it wasn’t obvious in the 2015 Ashes series, batsmen sometimes stand at the crease for an extremely long time. In the modern era, Brendon McCullum once spent nearly 13 hours in total batting. In such cases, the materials used in the batting gloves can be very important to the individual batsman. Calfskin leather is often preferred as it is particularly soft, although it has low durability. Kangaroo leather, especially when split into thinner layers, is one of the strongest leathers available, and is also commonly used.
A good cricket helmet is now an essential item of equipment. After the tragic death of Australian cricketer Philip Hughes in 2014, more research has gone into improving this vital area. Chris Rogers, who retired injured on the fourth day of the second test this series after being hit by the ball earlier in the series, said the foam clip-on stem guard he was using, developed after Hughes’ death, prevented him from being injured further.
The strength and durability of fibreglass make it a good choice for the helmet shell, although its weight means it is rarely the first choice. Carbon fibre, usually combined with aramid fibres, such as Kevlar, offers the same strength and durability with a much lower weight, but remains expensive. Both, however, offer much better protection than the traditional plastic.
Carbon steel, stronger than standard steel, is probably the cost effective choice for the protective grills, although titanium’s high tensile-strength-to-weight ratio makes it far more comfortable. HDFs are usually used for padding, because of their extremely low weight and high shock absorption.
Lastly, the abdominal guard or ‘box’. This is usually made from from high density plastic with a padded edge to maximise shock absorption.