Injury-Free Running, Second Edition: Your Illustrated Guide to Biomechanics, Gait Analysis, and Injury Prevention

Maximizing tendon flexibility is vital for avoiding injury and preventing age-related decreases in running performance because as we age, tendons naturally stiffen, which can be avoided with specific exercises and proper nutrition.

stance phase motions, this portion of the gait cycle has been subdivided into

the average three year old consumes 33% more oxygen when traveling at a fixed speed than an adult.

In slow hybrid running, the initial point of contact is almost always the outer heel, which makes initial contact only 2½ inches (6.35 cm) in front of the center of mass.

Because your stride length is so short, you don’t hit the ground very hard, and ground contact is typically made with the outside of the heel, with your foot only a few inches in front of you. To run fast while hybrid running, gradually increase your stride length and try to spend as little time on the ground as possible (you hit the ground like a

that people would choose an intermediate gait referred to as “pendular running.” In this gait pattern, which I like to call “hybrid running,” the stride length is shortened, the airborne phase is reduced, and the lower limbs are stiff for brief periods during stance phase

maintain economy, the best hybrid runners must “fine-tune” the positions of their limbs prior to contact in order to provide just enough stiffness to absorb and return energy at each successive running speed: Too much stiffness, and the center of mass moves up and down excessively and impact forces increase; too little stiffness, and the pathway of

we were to walk with our knees locked and our pelvis stiff (e.g., with a Frankenstein-like gait), the body’s center of mass would move up and down through a series of abruptly intersecting arcs, which would significantly increase the metabolic cost of locomotion because specific muscles would tense to accommodate the exaggerated up-and-down motions

The problem is that flattening the progression of the center of mass too much can be just as costly as not flattening it at all.