1. Patellofemoral Pain Syndrome (Runner's Knee)
Patellofemoral Pain Syndrome (PFPS): This is pain that occurs underneath, or around your kneecap and is often referred to as "Runner's Knee." About 40 percent of running injuries are caused in the knees. Runner's Knee typically flares up during or after long runs, long periods of sitting, or while moving down hills and stairs. The real kicker with this condition is that it typically affects adolescents and women who participate in running or jumping sports. Bummer.
2. Iliotibial Band Syndrome (ITBS)
Your IT band is a multipurpose tendon that runs down the outside of your thigh. It extends from the top of your pelvis down to your shin bone. Friction from your IT Band can cause you knee pain at the outside of your knee (lateral), or lower on your extremity. Lack of strength/ flexibility, skipping warm-ups, and ramping up your training too fast can all be risk factors in acquiring this condition. The pain levels will vary, but for some, the pain will be so immense that they'll wish they had Shin Splints instead. (Refer To No. 5)
3. Piriformis Syndrome
The piriformis is a small muscle located deep in your buttocks, behind your gluteus maximus. If it becomes tight it can put pressure on your sciatic nerve and cause you gluteal (buttocks) pain. It can often cause spasms as well as tingling and numbness along the back of the leg and possibly go into the foot. The pain is shooting and can be described by some like being shot by a stun gun. In simple terms: it sucks.
4. Plantar Fasciitis
This is the most common cause of pain on the bottom of your heel and foot and is usually more apparent with your first steps of the morning. Contributing risk factors can include being between the ages of 40 & 60, poor foot alignment, obesity, and especially activities that demand long periods of standing, walking, or running. This condition can be extremely annoying and debilitating like stepping on a lego in a dark room at 2 in the morning. True story.
5. Shin Splints
This is the pain you feel in front of your lower leg along your shin bone (tibia). This condition is a common cumulative stress injury caused by repetitive ground contact which could happen while running. Military training, high arches, flat feet, or suddenly increasing duration or intensity could all lead you down this path of misery. This may not be as bad as No. 2, but it's still pretty bad.