Why your knees might be destroying your back: the connection workers need to know
The knee-back connection is one of the most overlooked conversations in workplace injury prevention. If your people are doing physical work - trades, manufacturing, warehousing, transport - it's worth understanding before the body forces the issue.
The numbers don't lie.
Back injuries account for around a third of all sprain and strain ACC claims. In 2024, ACC paid out $2.9 billion supporting New Zealanders who couldn't work. These aren't just numbers on a spreadsheet - that's real people, real families, real careers cut short.
The good news? The majority of these injuries are preventable. And understanding the knee-back connection is a key part of that prevention.
The body works as a kinetic chain. The way one joint moves directly affects the joints above and below it. Ankle into knee. Knee into hip. Hip into lumbar spine. Disrupt any part of that chain and the rest compensates.
When your knees are unstable - whether from weak supporting muscles, previous injury, poor mechanics, or simple fatigue - the body doesn't just stop working. It shifts load. It recruits other structures to do the job. And more often than not, that compensation lands squarely in the lower back.
This isn't just something I've observed on the floor over 22 years. The science is clear.
A review examining nearly 10,000 studies - with 13 peer-reviewed papers and 4,976 participants across eight countries - found clear biomechanical and clinical connections between knee dysfunction and lower back pain, including changes in pelvic alignment and lumbar lordosis directly linked to knee instability.
Of 260 participants with knee osteoarthritis, 58.1% also had lower back pain. Critically, the combination created disability levels far greater than either condition alone - and the researchers concluded that treating knee and back pain separately, rather than as an interconnected system, likely leaves outcomes on the table.
In a study of 1,389 individuals with symptomatic knee osteoarthritis, the prevalence of concurrent lower back pain was 57.4% - described by the authors as "extraordinarily high" and "not well recognised" in clinical settings.
The mechanism is well understood: when knee extension is limited or the knee is unstable, it alters lumbar lordosis (the natural curve in your lower back), changes gait mechanics, and introduces compensatory load patterns into the spine. Over time, these changes accelerate wear and increase injury risk - both acutely and as a gradual process.
If you're doing physical work - carrying, lifting, lowering, pulling, pushing - your knees are working every single time. And if they're not stable, every single lift is loading your lower back in a way it shouldn't be.
The workers most at risk are those who:
- → Have a previous knee injury that hasn't been fully rehabilitated
- → Spend significant time in a half-squat or crouched position
- → Lift repeatedly through the day without warming up
- → Have weak quadriceps and hamstrings - the primary stabilisers of the knee
- → Work on uneven or hard surfaces for extended periods
The knee doesn't need to be obviously injured to cause problems. Subtle instability, reduced range of motion, or muscular imbalance around the knee is enough to alter lifting mechanics in ways that accumulate damage over time.
Correct technique distributes force through your legs and hips rather than concentrating it in the lumbar spine. Your knees act as the primary hinge. Strong, stable knees = a safe lift. A single correct lift protects you once. Correct technique every lift, every day, is what protects your career.
- → Assess the load before you touch it - can you manage it alone?
- → Position yourself - get close, feet planted shoulder-width apart
- → Bend at the knees, not the waist
- → Keep the load tight to your body through the entire movement
- → Drive through your legs with your core engaged
- → Turn your whole body to change direction - never twist under load
Three points of contact means maintaining three contact points with a stable surface at all times - two hands and one foot, or two feet and one hand. This forces a controlled, deliberate movement pattern where your knees track properly, your base is stable, and load on your spine is managed rather than reactive. Apply it wherever dynamic instability is a risk:
- → Climbing in and out of trucks or vehicles
- → Working from platforms or elevated surfaces
- → Moving through tight or uneven spaces carrying a load
- → Getting up or down from floor-level work
Technique matters in the moment. Strength is what protects you over a career. The muscles that stabilise the knee - quads, hamstrings, glutes - are the same muscles that, when strong, take load off the lumbar spine during lifting. Ten minutes a day, consistent, is all it takes.
- → Bodyweight squats - 3 sets of 15, knees tracking over toes
- → Single-leg Romanian deadlifts - builds posterior chain and knee stability together
- → Glute bridges - critical for knee alignment and lumbar support
- → Step-ups - functional, replicates lifting mechanics directly
- → Calf raises - ankle stability feeds directly into knee stability
Back pain that starts in the knees doesn't announce itself. It builds quietly, rep by rep, shift by shift, until one day it's a serious problem.
In physically demanding work, lower back pain is often the final expression of a chain of compensations that started somewhere else entirely. The knee is one of the most common starting points. The research is clear on that, and so is what I've seen in workplaces across New Zealand for over two decades.
The good news is the fix isn't complicated. Same principles that protect your knees protect your back. Get the technique right. Keep three points of contact. Build the strength that lets you do both without thinking about it.
If you want your team to understand the why behind safe movement - not just tick a compliance box - get in touch. We deliver workplace manual handling training across New Zealand.
Get in touch with Richie →Sources: ACC Injuries in New Zealand 2024 (ACC.co.nz) · Stats NZ Injury Statistics - Work-Related Claims 2024 · Iijima et al. (2018) Interaction between low back pain and knee pain contributes to disability level in individuals with knee osteoarthritis. ScienceDirect · Suri et al. (2010) Low Back Pain and Other Musculoskeletal Pain Comorbidities in Individuals with Symptomatic Osteoarthritis of the Knee. PMC/NIH · Alrazi et al. (2023) Biomechanical and clinical relationships between lower back pain and knee osteoarthritis: a systematic review. Systematic Reviews, BioMed Central · BMC Musculoskeletal Disorders (2022) - NZ regional sprains and strains surveillance programme.
The knee-back connection is one of the most overlooked conversations in workplace injury prevention. If your people are doing physical work - trades, manufacturing, warehousing, transport - it's worth understanding before the body forces the issue.
The numbers don't lie.
Back injuries account for around a third of all sprain and strain ACC claims. In 2024, ACC paid out $2.9 billion supporting New Zealanders who couldn't work. These aren't just numbers on a spreadsheet - that's real people, real families, real careers cut short.
The good news? The majority of these injuries are preventable. And understanding the knee-back connection is a key part of that prevention.
The body works as a kinetic chain. The way one joint moves directly affects the joints above and below it. Ankle into knee. Knee into hip. Hip into lumbar spine. Disrupt any part of that chain and the rest compensates.
When your knees are unstable - whether from weak supporting muscles, previous injury, poor mechanics, or simple fatigue - the body doesn't just stop working. It shifts load. It recruits other structures to do the job. And more often than not, that compensation lands squarely in the lower back.
This isn't just something I've observed on the floor over 22 years. The science is clear.
A review examining nearly 10,000 studies - with 13 peer-reviewed papers and 4,976 participants across eight countries - found clear biomechanical and clinical connections between knee dysfunction and lower back pain, including changes in pelvic alignment and lumbar lordosis directly linked to knee instability.
Of 260 participants with knee osteoarthritis, 58.1% also had lower back pain. Critically, the combination created disability levels far greater than either condition alone - and the researchers concluded that treating knee and back pain separately, rather than as an interconnected system, likely leaves outcomes on the table.
In a study of 1,389 individuals with symptomatic knee osteoarthritis, the prevalence of concurrent lower back pain was 57.4% - described by the authors as "extraordinarily high" and "not well recognised" in clinical settings.
The mechanism is well understood: when knee extension is limited or the knee is unstable, it alters lumbar lordosis (the natural curve in your lower back), changes gait mechanics, and introduces compensatory load patterns into the spine. Over time, these changes accelerate wear and increase injury risk - both acutely and as a gradual process.
If you're doing physical work - carrying, lifting, lowering, pulling, pushing - your knees are working every single time. And if they're not stable, every single lift is loading your lower back in a way it shouldn't be.
The workers most at risk are those who:
- → Have a previous knee injury that hasn't been fully rehabilitated
- → Spend significant time in a half-squat or crouched position
- → Lift repeatedly through the day without warming up
- → Have weak quadriceps and hamstrings - the primary stabilisers of the knee
- → Work on uneven or hard surfaces for extended periods
The knee doesn't need to be obviously injured to cause problems. Subtle instability, reduced range of motion, or muscular imbalance around the knee is enough to alter lifting mechanics in ways that accumulate damage over time.
Correct technique distributes force through your legs and hips rather than concentrating it in the lumbar spine. Your knees act as the primary hinge. Strong, stable knees = a safe lift. A single correct lift protects you once. Correct technique every lift, every day, is what protects your career.
- → Assess the load before you touch it - can you manage it alone?
- → Position yourself - get close, feet planted shoulder-width apart
- → Bend at the knees, not the waist
- → Keep the load tight to your body through the entire movement
- → Drive through your legs with your core engaged
- → Turn your whole body to change direction - never twist under load
Three points of contact means maintaining three contact points with a stable surface at all times - two hands and one foot, or two feet and one hand. This forces a controlled, deliberate movement pattern where your knees track properly, your base is stable, and load on your spine is managed rather than reactive. Apply it wherever dynamic instability is a risk:
- → Climbing in and out of trucks or vehicles
- → Working from platforms or elevated surfaces
- → Moving through tight or uneven spaces carrying a load
- → Getting up or down from floor-level work
Technique matters in the moment. Strength is what protects you over a career. The muscles that stabilise the knee - quads, hamstrings, glutes - are the same muscles that, when strong, take load off the lumbar spine during lifting. Ten minutes a day, consistent, is all it takes.
- → Bodyweight squats - 3 sets of 15, knees tracking over toes
- → Single-leg Romanian deadlifts - builds posterior chain and knee stability together
- → Glute bridges - critical for knee alignment and lumbar support
- → Step-ups - functional, replicates lifting mechanics directly
- → Calf raises - ankle stability feeds directly into knee stability
Back pain that starts in the knees doesn't announce itself. It builds quietly, rep by rep, shift by shift, until one day it's a serious problem.
In physically demanding work, lower back pain is often the final expression of a chain of compensations that started somewhere else entirely. The knee is one of the most common starting points. The research is clear on that, and so is what I've seen in workplaces across New Zealand for over two decades.
The good news is the fix isn't complicated. Same principles that protect your knees protect your back. Get the technique right. Keep three points of contact. Build the strength that lets you do both without thinking about it.
If you want your team to understand the why behind safe movement - not just tick a compliance box - get in touch. We deliver workplace manual handling training across New Zealand.
Get in touch with Richie →Sources: ACC Injuries in New Zealand 2024 (ACC.co.nz) · Stats NZ Injury Statistics - Work-Related Claims 2024 · Iijima et al. (2018) Interaction between low back pain and knee pain contributes to disability level in individuals with knee osteoarthritis. ScienceDirect · Suri et al. (2010) Low Back Pain and Other Musculoskeletal Pain Comorbidities in Individuals with Symptomatic Osteoarthritis of the Knee. PMC/NIH · Alrazi et al. (2023) Biomechanical and clinical relationships between lower back pain and knee osteoarthritis: a systematic review. Systematic Reviews, BioMed Central · BMC Musculoskeletal Disorders (2022) - NZ regional sprains and strains surveillance programme.