What are those black bands players wear on the training pitch?

Will Bruin - Houston Dynamo - Celebrates a goal at BBVA Stadium

They've been around for years, and you may have noticed them -- the undergarment male soccer players wear under, sometimes over, their jerseys or training tops.


And you may be wondering, just what is the purpose of those things? Presumably, unlike their female counterparts, the undergarment doesn't offer much physical support for male soccer players.

Well, the Houston Dynamo revealed their system in an article on their website Monday, explaining that the undergarment (called a "bib," go figure) includes a heart rate monitor and GPS tracker, all to keep track of the players' individual performances in training and in matches.


“Essentially, that’s our GPS system,” assistant coach Paul Caffrey told HoustonDynamo.com. “There’s maybe 200 data points that can be measured, but we ultimately measure or we do pay attention to player distance that they cover during the practices, during the games. We also measure the overall movement of each player, which is represented by a ‘player load’ value, which is essentially their work number. In addition, we measure the intensity and explosion of their movements. It essentially tells us the overall load that they had during the session.”


Mystery solved!