This article looks are what to consider in terms of short type, size, material and little extra functions.
Here’s what to consider when selecting running shorts:
You need something that is moisture-wicking (draws sweat away from your body) and quick-drying. Synthetic materials such as polyester, or polyester/spandex/nylon blend work well. They also tend to be long-lasting and more durable than shorts made from natural
Not that I’d recommend committing sins against decency, but shorter shorts can make a difference – especially in the heat. The longer the shorts are, the more heat
Liner and Seams
These exist so you don’t have to wear underwear, thus preventing chafing. However, when running long distances it is recommended to also apply a lubricant, like Bodyglide, down there. If you’re buying shorts from a reputable running company, chafing seams shouldn’t be an issue. Always do your dress rehearsal before a big run though, regardless of who made your shorts.
If you can get a pair of shorts with a small zip-pocket (preferably right at the back), then go for it. The additional weight and cost of getting the pocket are worth it for being able to easily store and access a couple of gels, salts, iPods, etc. on runs.
The effectiveness of compression gear seems to depend on who is wearing it. Many people enjoy the ‘lightly massaging’ feeling of wearing compression shorts and feel it aids with muscle recovery.
Minor secondary benefits of running with compression wear are that it can keep you warmer, and reduce chafing (but hopefully you’ve already eliminated the possibility of chafing using other methods).