" 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. Toronto 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. "

" Some people define jogging as an inefficient form of running which, for the given individual performing it, and all other conditions held constant, is less efficient than walking. Above a certain pace, running is a more efficient form of locomotion (requires less effort). Below that pace, running is less efficient than walking and makes no sense as a means of getting from point A to point B. A courier delivering a message on foot over 60 miles of road would expend more energy jogging the distance at a 13 minute mile pace rather than briskly walking it at the same pace. Slow jogging is pure exercise, with no practical application. Because jogging is inefficient, it's often associated with poor form. Joggers, or runners who are jogging, sometimes move in ways that wouldn't be done in a competitive running situation: excessively bounding into the air, landing heavily on the heel, carrying the arms too high, and so forth. San Antonio Running Club For these reasons, "jogger" and "jogging" are considered derogatory terms by some athletes who consider themselves runners. Other people use the terms "running" and "jogging" interchangeably, and see nothing derogatory about "jogging". "