Yes — it can. If your knees feel stiff, sore or ache when you stand up after sitting for a while, your chair setup may be the reason. Sitting with your feet off the floor, knees bent too sharply, or on a chair that presses behind your knees can all contribute to poor circulation, joint strain, and muscle fatigue.
The good news? You don’t need to buy an expensive ergonomic chair to make it work.
In this article, you’ll learn how to spot the problem, make quick adjustments, and protect your knees — starting today.
Why Does My Knee Hurt When I Sit?
Knee pain from sitting isn’t uncommon — and it’s often caused by how you sit, not just how long. When your knees stay bent for hours, especially at a desk, it reduces circulation around the joint and limits the flow of synovial fluid — the lubricant your knees rely on to move comfortably. Without it, the joint stiffens, and over time, even standing up can feel uncomfortable.
Sitting also encourages muscle inactivity. The longer your thighs and hips stay idle, the more the muscles around your knees — particularly the quadriceps — begin to weaken. This lack of support makes the joint more vulnerable to stress, even during everyday movements.
According to NHS guidance, staying in a fixed position for extended periods can place strain on joints and soft tissue. The average office worker in the UK now sits for more than seven hours a day — a routine that puts the knees under steady, low-grade pressure that builds up over time.
If your knees feel sore, heavy, or stiff after long periods of sitting, it’s likely not your age — it’s your chair and your posture.
Is My Office Chair to Blame?
Very possibly — especially if your knees feel tight, sore, or heavy after sitting. One of the most common causes of knee pain at a desk is an office chair that doesn’t fit your body. If your seat is too high, your feet dangle and your knees bend more than 90 degrees, increasing pressure on the underside of the joint. If the seat is too deep, it can press into the back of your knees, cutting off circulation and making your legs feel numb or stiff by the end of the day.
According to UK ergonomic standard BS EN 1335, a properly adjusted chair should allow your feet to rest flat on the floor, your thighs to be supported without pressure behind the knees, and your knees to form a right angle. Yet many standard chairs — especially in home offices or temporary work setups — fall short of these criteria.
It’s not just about the chair itself, either. Common habits like crossing your legs, tucking your feet under the seat, or perching forward shift your body weight unevenly and strain the knee joint over time. Combined with hours of sitting without movement, these small details can quickly turn into chronic discomfort.
If this sounds familiar, your chair setup is likely playing a bigger role in your knee pain than you think.
Quick Self-Check: Is Your Setup Hurting Your Knees?
Are you unsure? Is your chair the problem? Here are a few common signs your sitting setup might be putting unnecessary pressure on your knees — most of which go unnoticed during the workday.
- Your feet don’t rest flat on the floor when sitting
- Your knees are bent sharply, or raised higher than your hips
- The edge of the seat presses into the back of your knees
- You tend to cross your legs or tuck your feet under the chair for long periods
- You feel stiffness, aching, or numbness behind the knee after sitting for an hour or more
- You notice discomfort or resistance when standing up from your chair
These issues are especially common in UK home working setups, where dining chairs or low-cost swivel seats are often used in place of proper task chairs. Over time, poor positioning and static posture lead to increased pressure on the joint and weaker muscular support — both key contributors to work-related knee pain.
If you ticked more than one of the points above, it’s a strong sign your sitting posture or chair height needs adjusting.
How to Relieve Knee Pain Without an Ergonomic Chair
You don’t need expensive equipment to improve how your knees feel at the end of the day. Most people can alleviate discomfort by making a few simple adjustments to their sitting posture — even if they’re working from a dining chair or a basic office chair at home.
- Adjust your seat so that your feet rest flat on the floor and your knees are roughly in line with your hips. If your chair isn’t adjustable, a cushion or folded towel can help.
- If your feet dangle, use a footrest, a firm box, or even a ream of paper to support them. This takes pressure off the back of the knees and improves circulation.
- Sit back in the chair so your thighs are supported, but leave a small gap between the edge of the seat and the back of your knees to avoid compression.
- Keep your legs uncrossed and both feet planted firmly. Leg-crossing might feel natural, but over time it places uneven load through the knee joint.
- Stand up and move about at least once every 30 to 45 minutes. The longer you stay still, the more joint fluid stagnates, and the more likely your knees will stiffen.
These aren’t tricks — they’re grounded in what we know about joint pressure, circulation, and posture. If your current chair isn’t doing your knees any favours, these small changes can make a noticeable difference in how you feel by the end of the day.
Three Habits That Make Knee Pain Worse Without You Noticing
Even with the right chair height, certain everyday habits can still aggravate your knees — especially during long hours at a desk.
- crossing your legs or sitting with one foot under the other changes how your knee joint bears weight, often twisting it slightly out of alignment
- Perching on the edge of your seat means your legs do more work to stabilise you, placing unnecessary tension on the knees and lower back.
- Staying still for hours, even in a good position, can reduce joint lubrication and weaken the muscles that support the knee.
These behaviours are common in UK office culture — particularly during long meetings, when focusing on work, or when working remotely at the kitchen table. They may seem harmless at first, but they slowly build pressure on the joint.
Next, we’ll cover when knee pain is more than just discomfort — and when it’s time to get it properly checked.
When Should You Be Concerned About Knee Pain?
Occasional stiffness after sitting is common, but if your knee pain becomes persistent, it’s worth paying closer attention. Discomfort that lingers after you stand, worsens when climbing stairs, or starts affecting your mobility could be a sign of something more specific, such as patellofemoral pain syndrome (PFPS).
PFPS is a common condition in office-based workers, particularly those who spend long hours seated without movement. It typically presents as a dull ache around or behind the kneecap, often triggered by prolonged periods of sitting with the knees bent.
Clinical evidence shows that compressive forces in the patellofemoral joint increase significantly when the knee is flexed beyond 90 degrees for long stretches. Without proper muscle engagement — especially from the quadriceps — the joint lacks support and becomes more prone to irritation.
If your knee pain is becoming more frequent, affecting daily tasks, or accompanied by swelling or instability, don’t ignore it. A physiotherapist can assess your posture, gait, and muscle control to help prevent further stress and guide your recovery.
Small Daily Changes That Make a Big Difference
You don’t need a new chair or a radical change in routine to protect your knees. What matters most is how often you move and how you position yourself throughout the day. Even in the best chair, sitting still for too long can lead to stiffness, muscle fatigue, and joint pressure.
- Stand up every 30 to 45 minutes, even if just for a quick stretch or walk across the room. Regular movement helps circulate synovial fluid and keeps your knees responsive.
- Straighten your legs under the desk a few times each hour. Gentle extension helps offset the effects of constant flexion.
- Flex your ankles and shift your feet occasionally to keep the lower leg muscles active and support blood flow.
- Tense and relax your thigh muscles while seated — a simple way to activate the quadriceps and support the knee joint.
- Use breaks to take the stairs, walk outside, or cycle short distances. Low-impact movement is ideal for knee stability and overall joint health.
These habits don’t take much effort but are clinically proven to help prevent desk-related knee pain. In most cases, it’s the small, repeated behaviours — not one-off events — that decide whether your knees stay comfortable or become a daily issue.
Final Thoughts
Knee pain at your desk isn’t something you have to live with. As the research shows, the way you sit — and what you sit on — plays a bigger role than most people realise. From poor chair height to bad posture and lack of movement, small daily stresses can add up quickly.
The good news is that you don’t need to spend a fortune to start feeling better. Most of the discomfort associated with sitting stems from fixable setup issues and habits. Adjust your seat, move more often, and stay mindful of how your knees are positioned — your joints will thank you for it.
If your pain persists or worsens, it’s worth getting proper advice from a physio. However, in many cases, the first step to healthier knees is simply sitting more mindfully.
FAQs
What sitting position is best to avoid knee pain at a desk?
The ideal sitting position is one where your feet are flat on the floor, your knees are bent at approximately 90 degrees, and your thighs are supported without pressure behind the knees. Your hips should be level with or slightly above your knees, and there should be a small gap (around two fingers) between the edge of the seat and the back of your knees. This position helps maintain circulation, reduces strain on the joint, and keeps the muscles around the knee engaged.
According to UK ergonomic standards (BS EN 1335), this posture supports both comfort and joint alignment — especially when paired with regular movement breaks.
Can sitting in a chair too long cause long-term knee problems?
Yes, prolonged sitting — especially in a poorly adjusted chair — can contribute to long-term issues like patellofemoral pain syndrome (PFPS). Keeping the knee in a flexed position for hours reduces synovial fluid movement, weakens the quadriceps, and increases compression on the kneecap.
Research indicates that joint pressure increases significantly when the knees remain bent beyond 90° for extended periods. Over time, this can lead to inflammation, stiffness, and even reduced joint function if not addressed.
What features should I look for in an office chair to help with knee pain?
Look for an ergonomic chair that offers:
- Seat height adjustment, so your feet rest flat with knees at 90°
- Seat depth control, to ensure your knees don’t press into the edge
- A waterfall seat edge, which reduces pressure behind the knees
- Proper lumbar and back support, so you sit fully back without slouching
Chairs like the Sihoo Doro S100 or Sihoo M57 incorporate these features and are designed to minimise joint strain during prolonged sitting sessions.
