I am a senior involved in the Senior Olympics. I was always a runner in my younger years. So, I’m going to train for a half-marathon and I’m looking into ways to prevent running injuries for myself. I read in a runners magazine that I’m most likely to injure myself during the stance phase. I don’t remember any such term from my previous years of running. Could you please explain this to me?

Your gait (walking or running) cycle involves two main movements: stance and swing. Stance has several phases (e.g., contact, mid-stance and propulsion) but always involves having the foot in some contact with the ground.

Contact starts when the heel hits the ground. The knee is slightly bent just before contact. Just after contact, the foot pronates or rolls in. This allows the foot and leg to work together to provide a cushion that absorbs shock up the leg.

When the forefoot makes contact with the ground, the foot is flat. This is the start of the mid-stance phase of stance. During mid-stance, the foot and leg provide a stable platform for the body weight to pass over. The foot must not roll inward at this point or there will be too much movement and instability.

During mid-stance the other foot is in the swing phase (no weight on the ground at all). All the body weight is on the stance leg. That’s why mid stance is a time when lower limb is at increased risk for injury. Following mid-stance comes propulsion. Propulsion begins as the heel lifts. The big toe flexes, the arch lifts off the ground and the body is propelled forward. Anytime the foot is in the wrong position or does not function properly during the late mid-stance and propulsion phases of gait, there is an increased risk of injury.

Today’s running shoes are built to accomodate the stresses and strains put on the foot during mid-stance and propulsion. Improved shoewear and explanations for how they work may be why these terms seem new to you — they have become part of the focus of advertisers and running/training specialists.