Watering artificial turf provides a gold standard hockey surface!
Having witnessed the speed of hockey first hand at the London Olympics, it was so exciting to see the GB success in Rio 2016. I’d assumed that the pitch had been wet in London due to our weather, so I was surprised to see water flying from the hockey sticks in Rio every time the ball was struck. Turns out that a soggy pitch makes for a faster game…
Artificial hockey surfaces first started to replace natural turf in the 1970s; by 1976 artificial was mandatory for competitions. There are now three main choices for an artificial hockey pitch: a sand filled surface, a sand dressed surface and a water based surface as used at the Olympic games Hockey_Basic_Pitch_Info.pdf.
For both the sand based pitches, woven synthetic yarn is used to create a dense playing material. For full sand filled, typically the fibres will be 19 to 25 mm in depth and supported by sand all the way through (i.e. from top to bottom of each fibre). A sand dressed surface has a shorter pile, 16 to 20 mm, with sand used to stabilise 80% of the fibre depth.
The water based playing surface relies on water to keep a far shorter, dense pile of yarn in good playing condition; essentially the water reduces friction helping to prevent wear on the surface. When supported by water, each blade of artificial grass can move freely in all directions allowing the player to get their stick easily under the ball. This gives the player greater control and, as friction is reduced, allows for a faster game. Additionally, the water provides a cool top layer to the surface, helping reduce burns should a player fall over and scrape their skin (greenfields.eu/fih/water-based-hockey-pitch).
In the game of football, long turf – also known as third generation (3G) – offers a playing surface with longer strands of yarn infilled with crumbled rubber and a small amount of sand at the pile base. Whilst great for football this is no good for hockey, as the small diameter ball can become caught up increasing frictional drag. Indeed, the players would also experience this drag on their hockey sticks, reducing their control over the ball. For some recreational areas, 3G surface with a shorter pile can provide an adequate surface to support both football and hockey games (sportandplay.co.uk). But, for an Olympic performance, water irrigated pitches are the current gold standard.
As for why the hockey pitch was blue in Rio, the colour was first trialled in the 2012 London Olympics. Apparently the colour contrast with the yellow ball made it easier for televised audiences to watch the action. So, watered artificial blue pitches look set to stay with no push back – other than to start the game!