Effects of compression tights on calf muscle oxygenation and venous pooling during quiet resting in supine and standing positions. 
We applied near-infrared spectroscopy (NIRS) to evaluate in resting conditions the effects of compression tights (CT) on calf muscle oxygenation and venous pooling compared with Lycra(R) elastic tights (ET) and shorts (no compression) according to the body posture (supine vs standing).  Twelve sportsmen regularly involved in endurance training volunteered to this study.  Their average age, height and weight (+/-SD) were 26.5+/-2.6 years, 177+/-6 cm and 70.1+/-4 kg, respectively.  Tissue oxygenation index (TOI), deoxyhemoglobin (HHb), and blood pooling (Hbtot) of the right gastrocnemius medialis were continuously monitored at 2 Hz using a NIRS device (NIRO-300, Hamamatsu Photonics, Japan).  A home made transducer was used to measure applied pressure at the interface between skin and clothing over the calf area.  Subjects were asked to realize a supine-standing protocol (5 min for each position) by wearing CT, ET or shorts in a counterbalanced order on the same day.  HHb and Hbtot concentration changes were significantly lower whereas TOI was significantly higher by wearing CT compared with shorts and ET (P<0.001) as did supine compared to upright postures.  The mean pressures applied over the calf were 5.6 and 23.2 mmHg during supine and 5 and 24.1 mmHg during standing for ET and CT, respectively.  Pressures were significantly different among clothing according to the following rank order: CT>ET>shorts (P<0.001).  CT compared to ET have positive effects on calf muscle oxygenation and venous pooling in quiet resting positions.