Injuries can be an inevitable part of being a runner if you are not taking care to stretch, cross train and watch your nutrition. Sometimes however that achy, soreness you may feel in the first 24 to 48 hours after a long or hard workout may be mistaken for an injury, but in fact it is DOMS, delayed onset muscle soreness. DOMS is the result of working your muscles in an unfamiliar way causing microscopic tears and inflammation from eccentric movements; movements that cause muscles to contract while they lengthen. This may be experienced as stiffness, fatigue, muscle soreness and/or weakness. While DOMS can be annoying it is not permanent and can be avoided. Warming up completely; that is walking or running slowly until you start to sweat before moving on to the speed portion of your run, or run flat to the hill for your hill repeats instead of just starting at the bottom. Most programs prescribe a ten minute warm-up while we know most people require almost 20 minutes physiologically to warm up. Build up gradually. If your program calls for three to six repeats of something do three on the first outing working up to the six repeats over four weeks. Work the distance of your long run up slowly, no more than 10% per week, inserting a recovery week every fourth week to assist in repair. When doing weights go lighter and fewer reps until your body gets used to the new stress. Make stretching and/or rolling a habit after your workouts plus alternating warm and cool baths or a soak in Epsom salts, all of which can also reduce DOMS. If you still experience DOMS, things will feel better by the third day. To speed up recovery drink lots of fluid, do light easy workouts to increase blood flow which will help remove waste and reduce soreness, stretch and/or get a massage. Wait until all of your muscle soreness has gone before doing another hard workout. If your DOMS has not reduced or gone away within a week it is time to get it checked out to see if you have incurred an actual injury.