We included Tasc’s Velocity 5 inch short in part to test out the brand’s mix of bamboo and cotton, which wicks moisture and controls odor. Of those we tested, these were the most similar to traditional road running shorts, complete with the brief-shaped liner. The MosoTech liner brief is a cotton-bamboo mix for wicking and cooling and includes some spandex for compression and support. These are currently the only running shorts made by Tasc.

Fit
The 5 inch shorts had a relaxed fit that that felt loose and open during runs. The woven shell had a nice stretch and common run short taper. The liner’s stretch qualities stood out more than its supportive compression. The elastic waist included a drawstring for a customized fit. Its seams were prominent, but did not ride up immediately. However, as is the case with most brief style liners, the side seams could irritate the inner thighs on sweaty long days and at times had to be pulled down more.

Comfort
The loose stretch of the shorts and liner was comfortable before runs, and the cotton-bamboo fabric felt soft and cool against the skin. On shorter training runs the relaxed fit and fabrics felt airy and lightweight. During long runs, the sides of liner brief began to rub against the inside of legs, especially once the liner absorbed sweat and began to sag. The hanging loop inside the back of the waistband began to irritate nearby skin once sweat pooled there.

Breathability
On 90 degree days with low (10 percent) humidity, the liner brief retained sweat along the waist and at the bottom of the brief. Toward the end of long runs, and post-run this came to feel “soggy” according to one tester, as the cotton absorbed more than the bamboo could wick away. After runs, these shorts took much longer to dry out than the others we tested.

Features        
The inner brief is mostly cotton, with bamboo viscose and 10 percent Lycra spandex. The bamboo viscose did seem to wick sweat, and its anti-odor traits bore out through our testing. The one stash option is the taped zipper side pocket, which is smartly angled and positioned toward the back of the hip. Another fabric feature is the shell’s UPF +50 protection.

Durability
The Velocity shorts showed no signs of breaking down during testing. The stretchy shell helped keep it from tearing, and it withstood the sandpaper stress test well. The odor-eating bamboo liner held up through runs and multiple washings. The most likely fail point would be the elastic of the liner giving out.

Test runs varied from cool morning 15-milers at 9,000 feet to hot midday 5Ks at 5,000 feet. Late spring and early morning runs around Denver began in the mid-40s and crept into the 60s, with shade and exposure to sun and wind as extra variables common in trail running. Denver’s summer put temperatures into the 90s and even offered up moderate humidity to better test the breathability. A few runs in Central Texas weather, in particular the mornings with 80 percent humidity, guaranteed we sweat through even the most breathable pair of shorts. In all we ran over 600 miles in these shorts; between 75-150 miles in each pair.