Medically reviewed by Kashif J. Piracha, MD Key Takeaways The iliopsoas muscle is the major flexor of the hip joint, made up ...

New perk: Easily find new routes and hidden gems, upcoming running events, and more near you. Your weekly Local Running Newsletter has everything you need to lace up! Subscribe today. The human body ...

You might think that only DC Comics superhero The Flash could run at a speed of 200 strides per second. But in the animal world, special muscles—called "superfast ...