 On water @-@ based pitches , shorter fibres and wetted turf reduce friction and increase the speed at which the game can be played . However , these pitches require watering before , during and after the game and maintenance costs are significant . Sand @-@ dressed pitches cost more than sand @-@ filled pitches but are preferable for hockey as there is an absence of sand close to the playing surface . However , a multi @-@ purpose surface suitable for sports including association football and tennis is often required and hockey may not be the predominant sport . There are many different specifications and categorisations for artificial turf including shock absorption , surface rebound , friction , and strength outlined by the International Hockey Federation . Recently , longer @-@ pile third @-@ generation or 3G pitches have become popular , especially for football , but these do not usually meet the <unk> 's test criteria ; they are often too inconsistent and slow . 
