Over the past few years, there has been a tremendous increase in the use of third-generation artificial turf fields for both training and match play. These surfaces are so popular that in 2001 FIFA established standards for turf fields and have approved them for events such as the U-17 World Cup. The advent of turf field has also prompted a large number of research studies comparing injury risks between artificial and grass fields. For the most part, these studies show that the incidence injuries such as ankle sprains and ACL tears are not increased when training or playing on turf. However, a common complaint of players who spend much of their practice time on turf is chronic pain. A new study out of Japan finds that neither acute injuries nor complaints of chronic pain are increased in youth players who train predominately artificial turf.
Researchers tracked six Japan Football Association affiliated youth teams for one year. Four of the teams trained exclusively or primarily on grass while the other two trained primarily on turf. Players on these teams ranged in age from 12 to 17 years. In all, 301 players participated in the study. Acute injuries and chronic pain complaints were recoded daily by each team’s medical staff. In addition, coaches recorded the amount time each player trained and plated of grass or turf.
The most common acute injuries suffered by the players were ankle sprains and contusions (bruises). Ankle sprains accounted for about half of all injuries. However, there were no differences in the injury rates (the number of injuries per hours of play) between the teams training on turf and grass. This was the case whether the injuries occurred during training or during matches.
Low back pain and knee pain accounted for most of the chronic pain complaints. Again there was no difference in the incidence of total number of complaints between the grass and turf teams. However, there was a small increase in the incidence of low back pain complaints in the teams that trained on turf.
The researchers re-examined their data to better understand why players who train on turf seem to have more chronic back pain. One key issue is the time the teams spent training on turf. The turf teams trained 33% more than the grass teams. They trained about 8.5 hours per week and the grass teams averaged around 6.5 hours. That is, turf teams held the equivalent of one extra session per week. Why this occurred is not known but it is not surprising that this group of players experienced more chronic pain.
Two broad conclusions can be drawn from this study. First, training on the new artificial turf fields does not increase a youth player’s susceptibility to either acute injury or chronic pain. Like most of the previous research into the safety of artificial turf fields, this study suggests that these fields are safe for young players to train on.
Second, coaches should be aware that longer training, especially on turf, can raise the risk of chronic pain in young players. In this study low back pain was associated with time spent on turf. One advantage of artificial turf is that that it can be used throughout the year, regardless of weather. As a result, training sessions are less likely to be cancelled due to poor field conditions. Perhaps these “off days” due to weather actually allow young players to recover. While this study does not suggest that training on turf directly causes low back pain, it does suggest that coaches should monitor players closely in terms of chronic pain. They should be aware of the amount of time their teams train, especially on artificial turf.
Aoki H, Kohno T, Fujiya H, Kato H, Yatabe K, Morikawa T, Seki J (2010) Incidence of injury among adolescent soccer players: A comparative study of artificial and natural grass turfs. Clinical Journal of Sports Medicine, 20: 1-7.