The Louis Garneau Optimum short is made specifically to provide a superior level of flexibility and comfort. They are fitted with an AirSport chamois, which - as you can imagine from the name - has excellent ventilation for the rider.
The shorts are made with an ergonomic design with strategically placed panels that give the rider the best range of motion without discomfort. At the waist you'll find elastic, with an added drawstring. The wide "Powerband" at the bottom of the legs gives you compression (for circulation through the legs) and avoids the bottom of the kicks cutting in to your legs which is not a very nice feeling...
Another little feature is the internal pocket at the rear for stashing small valuables, and of course these knicks have flatlock seams and reflective detailing for visibility.