You may not have heard of this tongue-twister, but you practice proprioception every day. It's the ability to know where your limbs and joints are in space. Think of walking up a flight of steps. You can do it without watching yourself place your foot on each stair. Working out on an uneven surface, like a BOSU ball or a unpaved trail, helps improve proprioception skills and may even help prevent injuries like twisted ankles.

Did you know that girls are much more likely to suffer from torn ACLs--a serious knee injury that can require six months of recovery time? And that a great many of these injuries happen when girls play sports?

It's scary, but it's not a reason to keep your daughter off the playing field. After all, sports offer many benefits for girls. Instead, girls can stretch and strengthen their leg muscles (both of which will help protect their knee joint). And they can participate in special ACL conditioning programs. These help athletes build strength, and also teach safer skills and techniques that help protect knees.

Earlier this week, I had the opportunity to participate in a youth sports safety panel with top representatives from several sports; we discussed injury prevention and several other important issues. I'll be writing more about this in the coming days and weeks. Thank you to the National Football League for organizing and hosting this event.

That's the slogan for Coca-Cola's third annual "America Is Your Park" challenge. Now through July 15, you can vote for your favorite park online or by checking in there on Foursquare. The Foursquare check-in is worth five daily votes. You can double that by being active at your park: Log 20 minutes of physical activity on MapMyFitness for ten daily votes. You can also earn double votes for your favorite park on special days: the first day of summer, June 21; and the last weekend of the contest, July 13-14.

The park with the most votes will win $100,000, with runner-ups earning $15,000, $25,000, or $50,o00. The funds can be used to "restore, rebuild, or enhance" recreational areas. Currently, a park in tornado-damaged Moore, Oklahoma, is at the top of the leaderboard.

Once a child suffers one or more concussions, he has a harder time recovering from subsequent concussions, says a study published online today in the journal Pediatrics. "Children with a history of a previous concussion, particularly those with
recent or multiple concussions, are at increased risk for prolonged symptoms after concussion," the researchers conclude.

Their study followed 280 kids who were treated in the emergency department of a children's hospital. After being evaluated, most patients were advised to take time off sports, and two-thirds were told to avoid schoolwork, television, reading, and other cognitive tasks (this is called cognitive rest). Those who fit the following criteria experienced post-concussion symptoms longer than others:

• History of previous concussion (especially within the past year)
• Age 13 or older
• Female
• More severe symptoms right after injury
• History of depression
• No loss of consciousness at injury
• Abnormal neurological exam after injury

"The effect of previous concussion on symptom duration was strongly influenced by both the number of previous concussions and the time elapsed since the most recent previous concussion," the researchers note--making treatment and prevention of concussions extremely important. Since athletes are more likely to suffer concussions, parents of kids who play sports should take note.