Most runners focus on heart rate, watts or pace. These are important data, but they are only indicators of how much energy your "engine" is putting out. However, only a few people look at how much of that energy is literally evaporated on the way to the finish line due to poor mechanics. One of the biggest efficiency thieves is too much vertical oscillation.

Simply put: If you're bouncing too high in the air with each stride, you're not just running forward, you're essentially taking thousands of small jumps in a single workout.

Mechanical problem: Fighting gravity
When running, we want to use gravity as an ally, not as an enemy. Vertical oscillation is the measured amount by which your center of gravity (pelvis) rises and falls during a single running cycle.
   1. Rebound loss: Every extra inch upward requires extra muscular work of the calves and thighs. But this energy doesn't get you any closer to the finish line.
   2. Impact Destruction: What goes up must come down. The higher you jump, the greater the impact force that your joints, tendons and muscles must absorb.
   3. WOHLMACHINE Insight: Jumping too much dramatically increases the risk of stress fractures and achilles inflammation. Your "undercarriage" takes hits that might not occur at all with flat running.

Energy balance: why do you get "tired" sooner?
Think of your body as a hybrid system. You have a limited supply of glycogen (fuel). If you use 10% of your energy on unnecessary up and down movement, you will hit the proverbial "marathon wall" 10% sooner.
Elite runners have a vertical oscillation usually in the range of 6-10 cm. Hobby runners are often above 12 cm. The difference seems small, but multiply it by 40,000 steps (the average marathon) and you'll find that in sum, you've "jumped" Mount Everest for absolutely nothing.

How to calm your "system"?
The goal is not to "shuffle your feet", but to transform vertical force into forward force. Here are three mechanical keys:
   1. Increase your cadence (number of steps per minute): the longer you are in the air, the more time gravity has to pull you up and then slam you to the ground. A shorter, faster stride (ideally around 170-180 steps/min) will naturally knock the oscillation curve down.
   2. Full machine incline: don't bend at the waist. Imagine falling forward from your ankles. This will shift the rebound vector. The force will not go perpendicular to the ground, but obliquely backwards, which will shoot you forward like a projectile.
   3. Active Ankle: Instead of "slamming" the foot into the ground (a big drop and then a big pop), aim for a short, springy contact. The ankle needs to act like a stiff spring that instantly transfers the energy.