IN THE CLASSROOM
Understanding the running skill.
Running looks simple until you try to assess it. Here’s what’s really happening in every stride, the science behind it, and how Skill Grader turns it into seven things you can measure and teach.
Timothy Starkey
PE teacher and founder of Huddl · 6 min read · October 2026
Running is usually the first locomotor skill we assess, and it’s the one most students think they’ve already mastered. Nearly all of them can run. Far fewer run well. And when you’ve got 28 kids, one lesson and a stopwatch, it’s very easy to mistake the fastest runner for the best one.
Speed is the outcome. Technique is what produces it, and two students can post the same time with completely different movement patterns. That’s why Skill Grader looks at how a student runs, not how fast. To understand what it’s looking for, it helps to know what’s going on inside a single stride.
The gait cycle
Biomechanists describe running using the gait cycle, which starts when one foot hits the ground and ends when the same foot hits the ground again. Each leg goes through two phases. The stance phase is when the foot is in contact with the ground, and the swing phase is when it’s travelling forward through the air.
What separates running from walking is the flight phase. When we walk, there’s always at least one foot on the ground, and for a moment both feet are down together. When we run, that never happens. Instead there are two short windows in every stride where both feet are off the ground and the body is airborne. In faster running, each foot is on the ground for only a fraction of a second.
The running gait cycle. A simplified view of one stride. The exact proportions change with speed, but the pattern stays the same.
Braking and propulsion
During stance, the leg has two jobs. Straight after landing, it absorbs the impact and the ground pushes back against the runner, slowing them down slightly. This is the braking part of stance. Then, as the body passes over the foot, the hip, knee and ankle extend, the runner pushes down and back into the ground, and the ground reaction force propels them forward and up into the next flight phase. Tendons like the Achilles store some of the landing energy and return it during push-off, which is part of what makes running efficient.
Where the foot lands relative to the body’s centre of mass changes that balance. When a student reaches out and lands with the foot well in front of their hips, the ground force points backwards for longer and more of every step is spent braking. Coaches call this overstriding. A foot that lands closer to underneath the hips loses less speed and moves into push-off sooner.
Overstriding versus an efficient foot strike. The further ahead of the centre of mass the foot lands, the more the ground pushes back against the runner.
What the arms are doing
As the legs swing, they create rotation around the body’s vertical axis, twisting the hips one way and then the other. The arms swing in opposition to cancel it out. Biomechanist Richard Hinrichs showed in 1987 that during running, the angular momentum of the upper body and the lower body are similar in size and opposite in direction, so they largely cancel each other out. When a student’s arms cross the midline or barely move, you’ll often see the torso twist and the stride lose its rhythm.
Speed comes down to two numbers
However a student runs, their speed is the product of two things: how far each step travels and how many steps they take each minute. Increase either one without losing the other and the student gets faster.
It’s tempting to think faster runners simply move their legs faster. Research on adult runners by Peter Weyand and colleagues found something different. The fastest runners didn’t swing their legs through the air any quicker. They got faster by applying more force into the ground in a shorter time. For young students, that’s a useful reminder. “Move your legs faster” usually isn’t the cue. Strong, quick contact with the ground under the hips usually is.
The seven things Skill Grader measures
Skill Grader films the student side-on, finds the body and tracks each joint through the run. From that, it measures seven metrics, and each one connects back to the mechanics above.
Stride length ratio. How far each stride travels, compared with leg length. Measuring against leg length means taller students don’t get an automatic advantage.
Cadence. How many steps the student takes each minute. Together with stride length, it sets running speed.
Torso lean. How far the body leans forward. A slight lean from the ankles helps direct force forward instead of straight up.
Knee drive. How high the front knee lifts as the leg swings through. A strong knee drive sets up the next foot contact.
Foot strike. Which part of the foot touches the ground first, and where. Landing on the ball of the foot under the hips reduces braking.
Elbow angle. How bent the arms are as they drive back and forward. Arms bent at about 90 degrees swing efficiently and balance the rotation from the legs.
Stride symmetry. How even the left and right strides are. A big difference can point to a weaker side or a coordination gap.
A Skill Grader running result. Each metric is scored against thresholds for the student’s year level, then combined into one grade.
Each metric is scored against thresholds for the student’s year band, from Pre-primary through to Years 7 to 10, then combined into a single grade. The thresholds are published in the Skill library inside the app, so you can always see exactly why a student got the score they did.
What it looks like on the oval
You don’t need a biomechanics degree to use any of this. On the oval, the science comes down to a handful of things you can see and coach. A good runner lands on the ball of the foot, under the hips. The back leg folds to at least 90 degrees as it swings through. The front knee lifts until the thigh is almost level with the ground. The head and body stay steady with the eyes looking forward, and the elbows stay bent at about 90 degrees as the arms drive forward and back, opposite the legs.
These are the four errors Skill Grader picks up most often, with the cue I’d use for each.
Filming it properly
Running is filmed side-on. Set up two cones 10 metres apart and stand 3 metres back from the running path. Have the student run to the far cone and back past the first, and track them with the iPad so their whole body stays in frame. Film one student at a time.
Running might be the most familiar skill in PE, but there’s a lot going on in every stride. Once you know what to look for, it’s much easier to give feedback that actually changes how a student moves, and that’s the whole point of assessing it.
SOURCES
Hinrichs, R. N. (1987). Upper extremity function in running. II: Angular momentum considerations. International Journal of Sport Biomechanics, 3(3), 242–263.
Weyand, P. G., Sternlight, D. B., Bellizzi, M. J., & Wright, S. (2000). Faster top running speeds are achieved with greater ground forces not more rapid leg movements. Journal of Applied Physiology, 89(5), 1991–1999.
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