Interesting Psak: Prohibited to Participate in Marathon Tel Aviv and Triathlons

Someone asked Rav Yaakov Ariel, Chief Rabbi of Ramat Gan, if it is permissible to participate in the Tel Aviv Marathon that is fast approaching, considering it is a mixed-gender race. He also asked the same question about participating in Triathlons, events that include running, biking and swimming, that are mixed-gender races.

Rav Ariel's answer was simply, if people were dressed properly, it would be allowed. However, unfortunately, people are not dressed properly.
source: Yeshiva and NRG
uh oh. Good thing I am not participating in Marathon Tel Aviv...
Actually, this would apply not just to the Tel Aviv Marathon, but to all such marathons and sporting events. I know people who run a lot, but don't run marathons or other races only because of the way people (of the opposite gender) are dressed..
The truth is that this also applies to most of life - walking down the street, taking a bus, going to work, gooing to a mall, a supermarket - people are dressed immodestly everywhere. Granted, in sports clothes it is a lot of that concentrated into one place..
I find it interesting he did not employ the issue of it being a mixed-gender event, and only one of immodest dress.