Head Impacts in Water Polo

Who is most at risk and where is further research needed?

Head impacts and concussion

While there is a lot of focus on concussion’s negative health consequences, repetitive head impacts may still pose short and long-term health risks to athletes (1-4). In looking at the short and long-term effects of concussion, head impacts, in general, have gained increasing attention in football, lacrosse, soccer, and hockey (5-10). The intrinsic nature of these contact sports is aggressive and very physical.

Where does water polo fit?

Despite water polo being a full contact and rapidly growing sport in the U.S., head impacts in water polo have not been studied to any great extent. One of the only significant studies completed was a survey that asked athletes how many impacts they recalled receiving per game (11). As such, a study published in 2019, but carried out between 2015-2017, wanted to validate the above survey’s results and further explore sport-specific risk factors. The findings, described below, may indeed suggest that “highly-skilled, competitive, collegiate water polo players comprise a cohort of contact athletes for whom repetitive head impacts, apart from over concussion, might represent a risk factor for physiological dysfunction and neurological sequelae.”

The study

This study looked at three groups of Division 1 NCAA Men’s Water Polo players over 2015, 2016, and 2017 seasons. These athletes wore sensors on their water polo caps during sanctioned games and practices. Players were only monitored in games, whereas goalies were monitored in both games and practices due to the finding in the survey that goalies receive more head impacts during practices than in games (11). Data were collected across 23 practices and 23 games. Rather than analyze the data based on individual players, the impacts were analyzed based on position. Indeed, when a head impact occurred and was identified by the sensors, the research staff viewing the games made notes on player position specifically.

Validating the sensors

The sensors used contained a complex algorithm and a minimum threshold to identify and capture data on head impacts specifically (as opposed to capturing data on any movement of the head/cap). Despite this, research staff watched the games and the sideline device capturing the data from the sensors to validate the data and identify when a false positive occurred. All obstructed hits (such as when the player was underwater) or an incident where the cap came off the athlete’s head were included as false positives. Games in 2017 were also video recorded to assist with the validation of head impacts and to identify false positives. Of all recorded impacts, 46.39% were false positions. After accounting for false positives, there were a total of 424 verified impacts during games. Interestingly, no athletes were diagnosed with a concussion during the monitoring period, suggesting a potentially more significant issue regarding lack of concussion identification and management in water polo; this topic should be further explored.

Which positions are at most risk?

While there was a difference in impact frequencies across all player positions, the study came to several important conclusions:

1. Players in the offensive and defensive center positions sustained more impacts than other positions. This finding is consistent with the survey and could be attributed to a common water polo strategy where perimeter players get the ball to the center to optimize scoring opportunities. Centers also typically face away from the goal and their defender, thereby potentially increasing the risk of striking each other’s heads.
2. Left offensive positions experienced more impacts than the right offensive positions. This finding is consistent with another common offensive strategy where teams utilize their right-handed athletes by creating scoring opportunities on the left side of the pool.
3. Contrary to the survey, goalies had similar patterns of head impact risk (in terms of impact magnitudes and frequencies) in games and practice. This difference may be attributable to the study’s structure of a 1:1 game-to-practice ratio (23 games and 23 practices were reviewed), which does not reflect a true game-to-practice ratio.

Other findings

The statistics also found that field players (i.e., not goalies) sustained more hits on offense than on defense or during the transition. Relatedly, offensive perimeter players sustained more impacts than defensive perimeter players. Finally, no difference in impact frequency was noted between defensive and transition positions. 

Further Research Needed

The investigators’ further claims were that a similar pattern should be present in women’s collegiate water polo. However, it should be noted that this should not be assumed, and research should be completed in this area. The investigators also recommended that given the different patterns of head impacts and concussions seen across various levels in other sports, further research is needed to explore different water polo (competitive, recreational, developmental, etc.) (9, 12). Similarly, the investigators recommended researching whether head impact frequency and magnitude can be attributable to personal player styles or individual physiological characteristics, as this is currently unknown (13).

 Final thoughts: improving the headgear in water polo?

“intercollegiate water polo athletes may represent a valuable cohort for studying the acute and chronic effects of repeated head impacts in sport to extend our knowledge of athlete physiology and neurology and to inform evidence-based policies to promote the safety of athletes and the benefits of sport.”

The investigators made an interesting point that headgear in water polo is not required to meet specific protective standards. Despite the strong trend of findings that conclude headgear will not protect against concussions, player safety could be more generally improved by a water polo cap capable of reducing the forces associated with head impacts. Therefore, standardizing and requiring a certain protective capability of water polo caps may be worthwhile because, clearly, “intercollegiate water polo athletes may represent a valuable cohort for studying the acute and chronic effects of repeated head impacts in sport to extend our knowledge of athlete physiology and neurology and to inform evidence-based policies to promote the safety of athletes and the benefits of sport.”

References

* Cecchi NJ, Monroe DC, Fote GM, Small SL, Hicks JW. Head impacts sustained by male collegiate water polo athletes. PLoS One. 2019;14(5):e0216369. Published 2019 May 2. doi:10.1371/journal.pone.0216369

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