If you're running five times a week, make no single run greater than 33 percent of your weekly mileage. Injuries occur when repetitive running is performed too intensely, too frequently or too long. Even the most biomechanically inefficient people can avoid injury if they are careful to advance their training changes slowly. A medical practitioner should evaluate pain that does not improve with a few days rest. The most significant equipment decision for a runner is shoes.
Shoes become the protective barrier between the runner and the road.
Do not retrieve the decades old shoes from the closet for your new program. New, carefully fitted shoes reduce impact shock and chance of injury. Rotating more than one pair of shoes can reduce repeating the same shoe mechanics with each run. Shoes must be dry. Midsummer runs can soak shoes with sweat.