" A common saying for runners is that the sport is 90% mental. Recreational running became popular due to high-profile runners such as Steve Prefontaine . Race courses are usually held on the streets of major cities and towns but they could be on any sealed road. Most road races are either 5 km (3. 1 miles), 10 km (6. 2 miles), half-marathon (21. 097 km, 13. Club Running Sports1 miles), or marathon (42. 195 km, 26. "

" Some sources point to the origin of a runner's high being increased endorphin production as a result of exercise. Running injuries There are many injuries associated with running (due to it being a high impact activity). Common injuries are "runner's knee" (pain in the knee), shin splints, pulled muscles (especially the hamstring), "jogger's nipple" (soreness of the nipple due to friction), twisted ankles, and Iliotibial Band Syndrome. The most common running related injuries are due to over-use. Repetitive stress on the same tissues without enough time for recovery or due to improper form or muscle imbalances, leads to many of the above. Generally these can be minimized by warming up beforehand, wearing proper running shoes, improving running form, performing strengthening exercises, and getting enough rest. There is a very strong consensus among the running and scientific community that all of those can be very effective in minimizing or recovering from running injuries. Boston Running Club Another injury prevention method that is very commonly recommended in the running community, but is actually controversial is stretching. While stretching is often recommended as a near requirement to avoid running injuries, the relevant medical literature does not represent as much of a consensus that it is effective. "