Frequency, Magnitude, And Location of Head Impacts In Collegiate Water Polo

Abstract

Water polo is a contact sport that carries a risk of head injury, well documented in epidemiological surveys of USA Water Polo members and physician reports from international competition. However, a growing body of evidence suggests that head impacts—even those that are asymptomatic and go unreported—can produce brain injury. We know from both survey data and prospective monitoring of NCAA Division I athletes that the risk for head impacts is dependent on player position. It is unknown if these patterns extend to other levels of competition. PURPOSE To describe patterns of head impacts in intercollegiate club water polo (ICWP) competition. METHODS ICWP players (9 Men; 14 Women) were monitored during competition for head impacts using cap-worn inertial sensors to record impact time, head locations, peak linear acceleration (PLA), and peak rotational acceleration (PRA). Video recordings of competitions were reviewed to rule out false positives. The null hypotheses that impact frequencies were equally distributed among (i) player positions, (ii) game scenarios, and (iii) head locations were tested using Chi-square ‘goodness-of-fit’ tests. Significant differences were decomposed by chi-square tests. T-tests were used to test for differences in PLA and PRA between men and women. All results presented are corrected for multiple comparisons. RESULTS Men sustained 52 head impacts and women sustained 43 head impacts over 12 games, mostly on offense [71.2%, 62.8%; p<.001] and mostly at the center position relative to perimeter positions [p<.0001]. Impacts were most often sustained at the back of the head among men and women [p<.03]. Impacts ranged from low to high magnitude for men [means(range): PLA=39.7 (17.7-94.1)g; PRA=5.21(1.00-17.40) krads/sec2 )] and women [means(range): PLA=33.7 (16.2-72.6)g; PRA=4.02 (.20-14.00) krads/sec2 ]. Magnitudes did not differ between men and women [t(93)<1.98, p>.051]. CONCLUSION We observed a pattern of risk among male and female ICWP players similar to a pattern previously reported in Division I men’s water polo players. Considering the growing body of evidence suggesting adverse effects of repeated head impacts, our data suggest that players, particularly at the center position, might benefit from wearing protective headgear that attenuates the forces of these head impacts.