This week was all about finishing our testing. By the end of last week, we had mostly finished the water polo tests and so this week we focused on soccer. For soccer, we tested pressures of 5, 7, 8, 9, and 11 psi (the average is 8 psi). We launched these balls at each pressure at the Anthropomorphic Test Dummy (ATD) head with speeds from 35 to 55 mph in 5 mph increments. Similar to the water polo tests, we did 6 runs at each pressure and speed. However, we did not have head gear to test for soccer. As such, all soccer tests were done with the ATD head unprotected.

Unlike last week, weather conditions became a concern for us since rain was forecasted for a few days this week. In order to ensure that the ATD and Data Acquisition System (DAS) would not be damaged, we decided to forego our initial plan of testing on Monday. This meant an even greater time crunch to finish the experimentation by Thursday, but the team agreed it was a necessary precaution. Another hiccup occurred on Thursday, where the ball launcher ceased functionality. This occurred right as we were reaching our final speed for soccer, 55 mph. We were unable to fix the ball launcher before the day’s end, and therefore decided to finish our testing with some g-force tracker calibrations. We testing the g-force tracker by hitting it with a mallet, and now have data outputs from the tracker and from the internal accelerometers that we can compare to get an idea of how accurate the tracker is. Overall, all soccer testing and g-force was finished (with the exception of the 55 mph speed) in only two days!

A few initial calculations of our data with the water polo tests (specifically, the pressures at 40mph) follow our predictions that higher pressures result in greater G-Force magnitudes the head experiences. We also saw that the headgear does provide some protection, as the average G-Force magnitude was noticeably less for runs with head gear than for the tests without it by about 20%. Now, with testing complete, we can return the ATD and begin analyzing our experimentation results in more depth.

By Sherilyn Bumatay, Concussive Forces in Competitive Sports