There's a reason you don't see big, fat athletes contesting the 100m Olympic sprint and it's nothing to do with fitness. How is any moderately obese runner supposed to train properly when rivers of sweat keep short-circuiting their GPS sports tracker?
Now the floodgates of perspiration can burst asunder, thanks to the fully waterproof 310XT GPS watch from Garmin.
If it can cope with being immersed to a depth of 50 metres, it can certainly cope with a 'glowing' sprinter or 'rosy' cyclist.
The 310XT itself is on the heavy side, weighing in at a chunky 72g and measuring 5.5cm square. The 1.5-inch (160x100-pixel) monochrome screen displays time, distance and pace and can categorise multisport activities in one workout, including log transition time.
It has a battery life of up to 20 hours, and can signal pace changes or distances with both audible and vibratory alerts.
The 310XT can work with a optional new waterproof heart sensor, although the ANT+ wireless system won't transmit data underwater - so don't worry if that reassuring beep fades when you dive in. It doesn't look as though the integral GPS receiver will work while submerged, either.
Optional foot pods and cycling cadence sensor are also available, although they'll only be truly essential if you're still hoping to qualify for London 2012.
The 310XT will be available from May in the US at $350 (£235), with a worldwide release to follow.