Running Shorts - Choosing the right ones
The precise type of running short that you choose to run in is often a personal choice on what you feel comfortable wearing. Shorts do come in a variety of sizes and shapes, from loose fitting to others that more close relate to body shape.
They also come in a variety of lengths - for womens "knicker" shorts to ones that come down to the knee.
Whilst we are all driven by current fashions, both within the running community and more broadly (how often do you see people wearing the tiny shorts of the 70s and 80s now!), it is important to remember that functionality has to come before fashion and that you need to be able to run freely in whatever shorts you are wearing.
Choosing what is right for a particular run will be dependant on a variety of factors including weather, speed of running, likelihood of chaffing etc.
Running shorts should be made of lightweight, wicking and breathable material, no matter what the style is of the short. This is true even of the cycling style of shorts, where there will be a much higher lycra content.
Some running shorts will also have an inner brief which will help with support (particularly for men). When buying shorts it is pretty important to remember that men and women are constructed differently and although there are some unisex shorts on the market these don't generally work as well for runners as one designed specifically for your sex.
Cycling shorts are often warn, even on warm days with a dual purpose. On a cooler day it is to keep the body a little warmer. If it is a warm day and the runner is going to be running a long way, then they reduce the risk of chaffing between the legs (something which vaseline can also help with).
Some shorts are of a compression variety and are thought to increase blood flow and reduce injury in athletes.