Focus on the “runner’s five”: hamstrings, hip flexors, quadriceps, calves, and the iliotibial (IT) band, or connective tissue that runs from your hip down the outside of the leg. These are the muscle groups that tighten even when people aren’t running, from bad posture, sitting, repetitive activities, and just living. Though there are myriad exercises to choose from for each area (I suggest The Whartons’ Stretch Book for clear instructions and diagrams), what’s important is to do them correctly and regularly.
