Blog 2: Biomechanics of Athletes Explained.
Part 2: The Kinetic Chain - How Your Body Works Together
Welcome Back to Biomechanics ofThe Athlete Explained!
In Part 1, Dr. Keirstyn covered what biomechanics is and why it matters. Now let's tackle one of the most important concepts in understanding movement: the kinetic chain.
If you've ever had knee pain that turned out to be caused by your hip, or lower back pain that came from tight ankles, you've experienced the kinetic chain in action.
Your body doesn't work in isolated parts. Everything is connected, and when one link in the chain isn't working properly, the whole system compensates. Let's break down how this works and why it matters for athletes.
What is the Kinetic Chain?
Simple definition: The kinetic chain is the concept that your body functions as a series of connected segments (joints and muscles) that work together to produce movement.
Think of it like this: Imagine a chain with multiple links. If one link is weak or broken, the entire chain is compromised. Your body works the same way — foot, ankle, knee, hip, pelvis, spine, shoulder, elbow, wrist. They're all connected.
The principle: Force and movement transfer through this chain. When one segment doesn't move well (restricted) or move too much (unstable), the segments above and below compensate.
Why the Kinetic Chain Matters
Example 1: The Runner with Knee Pain
The Complaint: "My knee hurts when I run."
The Assumption: "Must be a knee problem."
The Reality: Often, the knee is the victim, not the culprit.
What's Actually Happening:
Weak hip abductors (glute medius/minimus) can't stabilize the pelvis during single-leg stance
Pelvis drops on the opposite side with each step
Femur (thigh bone) rotates inward
Knee tracks inward (valgus stress)
Knee takes excessive force it wasn't designed to handle
Pain develops
The Fix: Strengthen the hips. The knee pain resolves even though we never directly treated the knee.
Example 2: The Cyclist with Lower Back Pain
The Complaint: "My lower back aches after long rides."
The Assumption: "My back is weak."
The Reality: Limited hip flexion mobility forces the lumbar spine to compensate.
What's Actually Happening:
Cycling position requires hips to flex repeatedly
Tight hip flexors and limited hip joint mobility restrict how much the hip can flex
To reach the pedals, the lower back rounds excessively (compensating for the hip)
Repetitive spinal flexion under load creates disc and muscle stress
Back pain develops
The Fix: Improve hip mobility. Back pain resolves even though we focused on the hips.
Common Kinetic Chain Dysfunction Patterns
Pattern 1: Foot/Ankle → Knee → Hip
The Cascade:
Limited ankle dorsiflexion (ankle can't bend forward)
Knee compensates by tracking inward
Hip compensates by internally rotating
IT band and hip abductors get overloaded
Pain develops at knee or hip
Common In: Runners, basketball players, volleyball players
Pattern 2: Hip → Lower Back
The Cascade:
Weak or tight hips can't extend or rotate properly
Lumbar spine compensates by moving excessively
Facet joints, discs, and muscles get overloaded
Lower back pain develops
Common In: Cyclists, desk workers who train, anyone with prolonged sitting
Pattern 3: Thoracic Spine → Shoulder
The Cascade:
Stiff thoracic spine (upper back) can't rotate or extend
Shoulder compensates by moving excessively
Rotator cuff and shoulder capsule get overloaded
Shoulder impingement or rotator cuff pain develops
Common In: Swimmers, volleyball players, baseball/softball players, desk workers
Pattern 4: Core → Everything
The Cascade:
Weak or poorly functioning core can't stabilize spine and pelvis
Extremities (arms and legs) have unstable base to work from
Shoulders and hips compensate
Multiple areas develop pain
Common In: All athletes, especially those with high training volume and insufficient core work
Regional Interdependence: The Research Behind It
The concept of regional interdependence suggests that dysfunction in one region can contribute to pain or dysfunction in another.
Research Example: Studies show that hip strengthening reduces knee pain in runners, even when the knee itself isn't directly treated. The kinetic chain explains why.
Clinical Application: This is why good practitioners assess the entire kinetic chain, not just the area that hurts.
The Joint-by-Joint Approach
Physical therapist Gray Cook popularized the "joint-by-joint" approach, which categorizes joints by their primary need:
Joints That Need Mobility:
Ankle (dorsiflexion/plantarflexion)
Hip (flexion, extension, rotation)
Thoracic spine (rotation, extension)
Shoulder (full range of motion)
Joints That Need Stability:
Foot (arch control)
Knee (prevent valgus/varus collapse)
Lumbar spine (resist excessive motion)
Scapula (stable base for shoulder)
Core (trunk stability)
The Pattern: Mobility and stability alternate up the chain.
When It Goes Wrong:
A mobile joint becomes stiff → neighboring joint moves too much to compensate
A stable joint becomes unstable → neighboring joints work overtime to stabilize
Example: Stiff ankle → knee moves excessively → knee pain develops
How to Identify Kinetic Chain Issues
Self-Assessment:
1. Single-Leg Balance Test
Stand on one leg for 30 seconds
Watch for: Hip shifting out, pelvis dropping, knee collapsing inward, foot rolling in
If you see these compensations, the kinetic chain isn't functioning well
2. Overhead Squat Assessment
Squat with arms overhead
Watch for: Knees collapsing inward, heels lifting, excessive forward lean, arms falling forward
Each compensation points to a specific kinetic chain dysfunction
3. Movement Asymmetries
Can you rotate equally left and right?
Is one hip tighter than the other?
Does one shoulder feel different than the other?
Asymmetries indicate compensation patterns
Training the Kinetic Chain
Principle 1: Address Restrictions First
Before strengthening, restore mobility where it's needed. You can't strengthen through restricted range.
Example: If ankles are stiff, work on ankle mobility before loading squats heavily.
Principle 2: Build Stability Where Needed
Once mobility is restored, build stability to control that range.
Example: After improving hip mobility, strengthen glutes to stabilize the hip through that range.
Principle 3: Train Movement Patterns, Not Just Muscles
Isolated exercises have a place, but functional movement patterns teach the kinetic chain to work together.
Examples:
Squats (full kinetic chain integration)
Deadlifts (hip, core, upper back coordination)
Lunges (single-leg stability, full chain activation)
Push-ups (shoulder, core, hip coordination)
How Dr. Keirstyn Can Help
At Endurance Therapeutics, Dr. Keirstyn specializes in assessing the entire kinetic chain to identify where dysfunction originates. Many athletes come in with pain in one area, only to discover the root cause is somewhere else entirely.
Through comprehensive movement assessment, Dr. Keirstyn identifies:
Which joints are too stiff (need mobility work)
Which areas are too mobile (need stability training)
Where compensations are occurring
How your sport-specific movements are affected
Treatment and education focus on:
Restoring mobility where needed (joint mobilization, soft tissue work)
Building stability and strength in weak areas
Teaching you how your body should move
Creating a plan to address the root cause, not just symptoms
Book an assessment to understand your kinetic chain and stop chasing symptoms without addressing the real problem.
What's Next
In Part 3, we'll explore force, load, and impact — understanding how your body handles stress during movement. We'll break down ground reaction forces, why some movements hurt more than others, and how to train your body to handle high loads safely.
📍 Endurance Therapeutics | Oakville, Ontario
📞 905-288-7161