Sciatica is nerve pain that usually starts in the lower back or buttock and travels down the leg, often past the knee, and tends to feel like burning, tingling, or an electric-shock sensation.
The short version
- Tight hamstrings cause a duller, more localised ache at the back of the thigh that usually doesn't spread past the knee and doesn't come with tingling or numbness.
- If you're not sure which one you have, a doctor or physiotherapist can help tell the difference using a simple leg-raise test alongside the rest of your history and examination — the test on its own isn't perfect, so it's one piece of the picture rather than a final answer.
Why it happens
Sciatica happens when a nerve in your lower back — the sciatic nerve or one of its roots — gets irritated or compressed, often by a disc or by tight structures nearby. Because that nerve runs from your lower back, through your buttock, and all the way down the back of your leg, irritation anywhere along that path can cause pain, tingling, numbness, or a burning feeling anywhere along the same line, often past the knee and sometimes into the foot.
Tight hamstrings, on the other hand, are a muscle issue rather than a nerve issue. The hamstrings are a group of muscles at the back of your thigh, and when they're tight or overworked, they tend to produce a duller, more localised ache or tightness that generally stays in the back of the thigh rather than spreading down past the knee. This kind of tightness is usually the same on both legs and often eases somewhat with movement.
The confusing part is that irritation of the sciatic nerve can sometimes feel like tightness in the same area as the hamstrings, since the nerve runs right alongside them. This is one reason it's genuinely hard to tell the two apart just from how it feels — clinicians often use a specific test, gently raising your straightened leg while lying down, to see whether it's the nerve or the muscle that's limiting the movement and reproducing your usual pain.
⚠️ When to see a doctor in person
Get emergency care straight away — go to A&E or call 999 if you have numbness around your groin, genitals, or the area you'd sit on (saddle numbness), a change in genital sensation, sudden loss of bladder or bowel control, or leg weakness that's getting worse. These can be signs of a rare problem where nerves at the base of the spine are being squeezed, and it needs same-day emergency treatment.
- Book an appointment if the pain spreads past your knee with tingling, numbness, or a burning feeling, it hasn't improved after a couple of weeks, or it's affecting one leg much more than the other with no clear muscular cause.
Most leg pain is muscular, and even genuine sciatica usually settles within a few weeks to a few months.
What tends to help either way
- Stay reasonably active rather than resting completely — gentle movement is usually better tolerated than long periods of bed rest for both causes.
- Avoid positions that clearly reproduce sharp, shooting pain, like fully bending forward with straight knees if that brings on nerve-type symptoms.
- Apply heat to a tight, achy hamstring for general comfort — this is more suited to muscle tightness than nerve irritation.
Starter exercises
Only if your pain is mild and there are no red-flag symptoms above.
- Gentle hamstring stretch — 3 reps each side, hold 20 seconds. Sit on the edge of a chair, straighten one leg with your heel on the floor, and lean forward gently from the hips until you feel a mild stretch at the back of the thigh. Stop well short of anything sharp.
- Gentle hamstring and nerve stretch — 2 sets of 10, slow and controlled. Sitting tall, slowly straighten your knee while gently pulling your toes up towards you, then relax. This stretches the hamstring and the sciatic nerve together, so it can be more provocative than it sounds — keep it small and well within a mild, easy range. It should feel like mild tension, never sharp, shooting, tingling, or numb — stop straight away if it does, and skip this move altogether if your leg symptoms are more than mild.
Bottom line
Sciatica is nerve pain that typically radiates past the knee with tingling or burning, while tight hamstrings cause a more localised, duller ache that usually stays above the knee. The two can feel similar, so if you're unsure, a physiotherapist or doctor can help work out which one you're dealing with, using a leg-raise test as part of a fuller assessment. Numbness around the groin or genitals, bladder or bowel changes, or worsening leg weakness need emergency medical attention straight away.