Movement Analysis • March 15, 2026
Understanding the Running Skill: The biomechanics behind running.
Movement Analysis • March 15, 2026
By Timothy Starkey
Running is one of the first locomotor skills children develop, and it remains one of the most fundamental movement patterns in our lives. Although running looks simple (I mean heck, we all know how to run, right?), but under the surface lies a complex coordination of systems & mechanics working in synchronicity to propel the body forward like a perfectly timed orchestra, where every instrument must come in at exactly the right moment. Our muscles generate force, joints absorb impact and nervous system coordinates timing and rhythm. All of this happens in fractions of a second, over and over as each stride carries the body forward.
When you start to unpack what’s actually happening during a running stride, it becomes clear that running isn’t just “moving fast”. It’s a carefully balanced exchange of force, stability, rhythm, and coordination. And this is where things get interesting for us as Physical Education teachers.
In this article, I'd like to delve a little deeper into the running skill; the key systems at work, why it can be so challenging to assess in PE, and how Skill Grader can help teachers better understand and measure biomechanical systems with ease.
As PE teachers, we're taught to look for key markers in a running technique:
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High knee drive
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Eyes focussed in the direction of travel
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A slight forward lean of the torso
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Lands on the balls of their feet
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Elbows bent
Don't get me wrong - these cues help us identify whether a student is developing efficient running mechanics. But in my humble opinion, they are somewhat narrowing of what's really happening, as well as being highly subjective. I'm sure at some point in your career, you've fallen into the trap of 'that student can run really fast, so they must be a highly adept runner'. But that's not always the case. Speed is simply the outcome we see, not the underlying movement quality that produced it and two students can reach the same speed using completely different mechanics. I'm certainly not suggesting we all venture out to get a degree in biomechanics, but if we want to truly understand how well a student runs, we need to look beyond the surface and consider the movement patterns that produce the result.
While teachers aren’t expected to analyse biomechanics in detail, these underlying movement patterns shape the visual cues we already use to assess students.
So what should teachers actually be looking for when assessing the running skill?
To answer that question, we need to take a look at what biomechanical systems are at play.
The Stride Cycle
Running is made up of a repeating sequence known as the 'stride cycle' or 'gait sequence'. Each stride consists of three key phases:
1. Stance phase
The period when the foot is in contact with the ground. During this phase the body absorbs impact forces, stabilizes the lower limb, and generates propulsive force to drive the body forward.
2. Swing phase
The period when the leg moves forward through the air after toe-off, preparing for the next ground contact. During swing, the hip flexes, the knee recovers forward, and the foot repositions for the next landing
3. Flight phase
A brief period unique to running where both feet are off the ground simultaneously between steps.
Each stride cycle consists of:
Ground contact → Push-off → Flight → Landing.
All of these phases occur incredibly quickly. In sprinting, ground contact may last less than 0.2 seconds, meaning the body has only a fraction of a second to absorb impact forces, stabilize the ankle, knee, and hip joints, and generate the propulsive force needed to drive the body forward again. Biomechanically, this requires rapid coordination between the muscles, tendons, and nervous system to manage both force absorption and force production within a single step. This is why running is often described as a series of controlled falls and recoveries, where the body repeatedly catches and re-launches itself with each stride.
In a school context, this process becomes even more interesting because students are still developing their coordination, strength, and movement control. Younger runners often compensate with shorter strides, excessive vertical movement, or inefficient arm action as their bodies learn to manage these systems. Efficient running therefore depends on several key mechanical components working together; posture, arm-leg coordination, stride rhythm, and the ability to produce and control force through the ground. When these elements begin to synchronize, students not only run faster, but move with greater efficiency, balance, and control.
Running Speed = Stride Length × Stride Frequency. Increase either one efficiently, and running speed improves.
Additional Running Mechanics
While running technique can be analysed in great detail, several additional mechanical factors play an important role in how efficiently a person runs. In a school setting, these mechanics influence not only running speed, but also coordination, balance, force production, and movement efficiency.
Arm Drive
Arm movement plays a critical role in maintaining rhythm, balance, and rotational control during running. Because the arms and legs move in opposition, effective arm drive helps stabilize the torso and supports efficient leg turnover.
From a biomechanical perspective, the arms contribute to angular momentum control, helping counteract the rotational forces generated by the lower body.
When observing students, teachers may look for:
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Arms swinging primarily forward and backward, rather than crossing the midline of the body
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Elbows flexed at roughly 90 degrees
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Shoulders remaining relaxed, without excessive elevation or tension
Inefficient arm mechanics can disrupt running rhythm and increase unnecessary upper-body movement, reducing overall efficiency.
Torso Lean
Efficient running involves a slight forward lean originating from the ankles, rather than bending forward at the waist. This body position helps align the center of mass so that ground reaction forces are directed forward rather than vertically.
Maintaining a stable trunk position also allows force generated by the lower body to be transferred more effectively through the kinetic chain. When runners lean excessively at the hips, it often leads to reduced stride length, increased vertical oscillation & less efficient force application into the ground. Teachers may observe whether students maintain a stable, upright posture with a subtle forward lean while running.
Knee Drive
Knee drive refers to the forward and upward movement of the thigh during the swing phase of running. This action plays an important role in generating stride length and positioning the foot for the next ground contact. Effective knee drive allows the runner to rapidly reposition the leg underneath the body, supporting both stride frequency and efficient force production during the following stance phase.
In younger students, knee drive is often inconsistent or limited, which can result in:
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Short, shuffling steps
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Reduced stride length
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Slower leg turnover
Encouraging students to lift their knees and drive the thigh forward can help develop more powerful and coordinated running mechanics.
Foot Strike
Foot strike describes how and where the foot contacts the ground during the stance phase of the running stride.
In efficient running, the foot typically lands close to the body’s center of mass, allowing the runner to transition smoothly into the next stride while minimizing braking forces.
When the foot lands too far in front of the body — often referred to as overstriding — the runner creates a braking effect that reduces forward momentum and increases impact forces.
Teachers may observe whether students:
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Land with the foot roughly underneath their hips
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Maintain relatively short ground contact times
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Avoid excessive reaching or overstriding with the lead foot
Efficient foot placement helps maintain running rhythm and allows force to be directed into forward propulsion rather than deceleration.
While these mechanical factors play an important role in running performance, many of them occur in fractions of a second and are difficult to accurately observe with the naked eye.
Why Running Is Difficult to Assess in Schools
Although teachers can observe some aspects of running technique, objectively assessing these mechanics is extremely challenging. Most elements of the stride cycle occur in fractions of a second, with ground contact lasting less than 0.2 seconds during faster running. In a typical class environment, teachers assess sometimes upwards of 30 students in a single lesson, while managing behaviour, engagement, tending to student needs, managing toilet breaks, shoelaces.. you name it! This makes it super difficult to consistently capture subtle differences in mechanics.
At this point, some of you might be wondering: why do we even need to think about biomechanics when assessing running? They’re just kids, right?
I’ve asked myself the same question many times. In a busy school environment, it can feel unnecessary to analyse something as everyday as running in such detail. After all, the goal of Physical Education isn’t to turn every student into an elite sprinter.
But the reason these mechanics matter has less to do with speed and more to do with movement development.
When students develop efficient running mechanics, they tend to move with greater balance, coordination, and control. Over time, these movement foundations contribute to what we often refer to as physical literacy — the confidence and competence to move effectively in a wide range of environments. Understanding how students run can therefore give teachers valuable insight into their broader movement development.
Introducing Skill Grader
Here at Huddl, we’ve developed what we believe to be the world’s first computer vision assessment system designed specifically for fundamental movement skills in Physical Education.
Using advanced pose-tracking technology and proprietary grading algorithms, Skill Grader analyses how students move during an activity and converts those movements into measurable biomechanical data. Rather than relying solely on subjective observation, teachers can access objective insights into how a student performs key components of a movement skill.
When a student performs the running skill, the system detects key joint positions across the body and tracks how those joints move throughout the stride cycle. From this information, Skill Grader is able to evaluate several important aspects of running mechanics.
These include:
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Torso lean – how the runner positions their trunk relative to the ground during movement
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Elbow angle – the angle and movement pattern of the arms during arm drive
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Stride symmetry – whether both legs are contributing evenly to the running pattern
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Stride length ratio – the relative distance covered by each stride
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Ground contact time – how long the foot remains on the ground during each step
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Flight time – the duration when both feet are airborne between strides
Together, these metrics provide a clearer picture of how efficiently a student is moving. Instead of simply observing whether a student runs “well” or “poorly,” teachers can gain deeper insight into the mechanical patterns that underpin the movement.
Torso Lean
Torso lean refers to the angle of the runner’s trunk relative to the ground during movement.
Efficient running typically involves a slight forward lean originating from the ankles, which helps position the body’s centre of mass slightly ahead of the base of support. This alignment allows ground reaction forces to contribute more effectively to forward propulsion.
When runners bend excessively at the waist instead of leaning from the ankles, it can disrupt balance and reduce the efficiency of force transfer through the kinetic chain. Skill Grader measures torso lean as the angle of the upper body relative to vertical, expressed in degrees, allowing posture to be evaluated consistently throughout the stride.
Elbow Angle
Elbow angle describes the degree of flexion at the elbow joint during arm drive.
During running, the arms and legs move in coordinated opposition. Maintaining an elbow angle close to 90 degrees allows the arms to swing efficiently while helping counterbalance the rotational forces generated by the lower body.
If the elbow angle becomes too extended or excessively tight, arm movement can become inefficient, which may disrupt running rhythm and reduce overall coordination. Skill Grader tracks elbow positioning by measuring the angle formed at the elbow joint between the upper arm and forearm, expressed in degrees, across the running motion.
Stride Symmetry
Stride symmetry refers to how evenly both sides of the body contribute to the running pattern.
In symmetrical running, the left and right legs produce similar stride characteristics, including timing, joint positioning, and movement patterns.
Asymmetries can occur when one side of the body produces more force or moves differently than the other. In developing runners, this may appear as uneven stride patterns, inconsistent timing, or subtle differences in leg mechanics. Skill Grader evaluates stride symmetry by comparing left and right stride characteristics, identifying differences in timing and movement that may indicate asymmetry.
Stride Length Ratio
Stride length ratio describes the relative distance covered by consecutive strides during running.
Rather than simply measuring stride length in isolation, the ratio compares how stride length changes between steps. This helps identify whether the runner maintains consistent stride mechanics throughout the running pattern.
Large variations in stride length can indicate coordination challenges, inconsistent force production, or developing movement patterns. Skill Grader measures stride length using horizontal displacement between successive foot contacts, expressed as a relative ratio between strides to assess consistency in forward movement.
Ground Contact Time
Ground contact time refers to the duration the foot remains in contact with the ground during each step.
During running, this contact period is extremely brief. In faster running speeds, it can occur in less than two tenths of a second.
Shorter contact times often indicate that the runner is able to generate force quickly and transition efficiently into the next stride.
Skill Grader measures ground contact time as the duration between initial foot contact and toe-off, expressed in seconds.
Flight Time
Flight time refers to the period when both feet are airborne between steps.
This phase occurs after the runner pushes off the ground and before the next foot makes contact.
Longer flight times can indicate that the runner is generating sufficient propulsion during the push-off phase of the stride. However, excessively long flight phases may also indicate inefficient vertical movement rather than forward propulsion. Skill Grader measures flight time as the duration between toe-off and the next foot contact, expressed in seconds.
How Skill Grader Benchmarks Running Mechanics
To ensure assessments are fair and developmentally appropriate, Skill Grader compares each biomechanical metric against age-specific benchmark ranges.
These ranges are based on research in youth movement development and are scaled across year bands from Foundation to Year 10.
Below is an example of how running mechanics are evaluated for Year 5–6 students.
Research and Evidence
The benchmark ranges used by Skill Grader are informed by research in youth biomechanics, sprint mechanics, and fundamental movement development.
Studies in running biomechanics consistently show that factors such as stride symmetry, ground contact time, and trunk posture play an important role in running efficiency and force production.
These benchmarks are not intended to define “perfect” running mechanics. Instead, they provide a developmental reference point that helps teachers identify movement patterns that may support or limit efficient running in children.
As more assessments are performed through the Huddl platform, these benchmarks will continue to evolve to reflect real-world movement patterns observed in school settings.
So what does this all mean for PE Teachers?
PE teachers have always relied on observation and professional judgement when assessing movement skills. Skill Grader doesn’t replace that expertise, it supports it. If you disagree with Skill Grader's output, we've added an 'edit grade' feature.
For the first time in schooling history, objective biomechanical measurements are now possible and teachers can gain a MUCH clearer picture of how a student moves. Instead of relying solely on visual impressions, teachers can see measurable indicators that determine learning progression.
This makes it easier to:
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identify movement inefficiencies
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track improvements over time
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provide more specific feedback to students
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support fair and consistent assessment across a class
Most importantly, it allows teachers to focus on what matters most — helping students develop confident, efficient movement patterns that support lifelong participation in physical activity.
Understanding the Running Skill: The Biomechanics behind running.
Movement Analysis • March 15, 2026
By Timothy Starkey