Well, I have actual, printed substantiation to back up the decision that Rachel (our Trainer) and I came up with last year when we made a new team rule banning flip-flops. This is an article from Training &Conditioning from October 2008.
"Flip-Flops & Athletes: A Bad Combination"
It's not hard to imagine why flip-flops can be bad for your feet, since they offer very little cushioning and virtually no arch support. But now, research from Auburn University's Department of Kinesiology provides specific data about how flip-flops can affect athletes who wear them.
"There's plenty of anecdotal information out there that says flip-flops can cause problems," says graduate student Justin Shroyer, MA, CSCS, who co-wrote Auburn's flip-flop study with Professor Wendi Weimar, PhD. "We wanted to look at them scientifically to see what effects they have."
In the study, researchers analyzed the way 39 college-age men and women walked while wearing flip-flops, then compared it to the way they walked in athletic shoes. With flip-flops, subjects took shorter strides, hit the ground with less vertical force, and increased the "attack angle" of their ankles during the leg's swing phase. When participants switched to sneakers, some of the gait changes remained, causing discomfort.
The study raises questions that Shroyer and Weimar would like to answer with further research: How do muscle recruitment patterns differ when wearing flip-flops versus athletic shoes? Does the shortened stride put athletes at risk for injury? How much energy do foot muscles have to use to grip the flip-flop? Does the flip-flop step cause muscles to work harder?
Shroyer stops short of drawing too many conclusions from the initial study, and hasn't yet tossed his own flip-flops. But he does caution athletes against wearing them all day long. "Flip-flops were made for the beach, the pool, and the shower, and that's where they should be worn," he says. "There are some great things about flip-flops: They're easy to take off and put on, and they help keep feet cool. But they're not the best choice for everyday footwear.
"If athletic trainers are trying to provide an optimal environment for their athletes, they'll want to eliminate anything counterproductive," adds Shroyer. "If athletes want to keep wearing flip-flops, they should look for ones with more arch support and a thicker cushion. And they should replace them every three or four months. If they have to break out the duct tape, they've gone way too far."
Thank you, Rachel, for giving me this article. This helps spell out why we've done away with wearing flip-flops during our season!! It made complete sense to me when Rachel and I talked about it last year, but this just gives us more printed support. Right now, it's too cold to wear them anyway, or should be, so this team rule helps confine the flip-flop wearing of the team to the times when they were designed for: summer months at the beach!