The short answer
Squat or Lunge?
Start with squats to a box at a depth that does not hurt, and add reverse lunges once those are calm. A squat splits the load between two knees, and the box lets you set the depth to the centimetre. A lunge puts most of your weight on one knee and asks you to balance as well. If the sore spot is the front of the knee or the kneecap, keep the bend shallow to begin with, since kneecap stress climbs as the knee bends toward 90 degrees. When you do lunge, step backwards. The forward lunge loaded the kneecap more in a lab comparison.
Side by side
| Question | Squat | Lunge |
|---|---|---|
| What it is | Sit your hips back and down between your heels, then stand up tall. | Step one foot back or forward, lower the back knee toward the floor, then stand. |
| Equipment | Nothing; a chair or box to set the depth | Nothing; a wall to hold for balance |
| Load per knee | Shared between both legs | Most of it on the front leg |
| Controlling depth | Exact: you sit to a chair, box or stack of cushions and stop there | Looser, because the back knee sets it. A cushion under it marks the spot |
| Kneecap load | Climbs as the knee bends toward 90 degrees, and with added weight | More when you step forward than back, and more in the deep part |
| Balance | Easy. Hold a door frame if you need to | Moderate. The narrow stance wobbles before the legs tire |
| Front of the knee or kneecap hurts | The better start, shallow first | Reverse only, short range, later |
| Inside of the knee hurts | Film a set from the front and check the knees track over the middle toes | Reverse lunges in a straight line. Leave side and curtsy lunges for later |
| Going down stairs hurts | Practise a slow lowering to a box height the knee accepts | Begin single-leg work with step-ups. Going up a step stressed the kneecap less than coming down |
Choose the squat when
- The front of the knee or the kneecap is what hurts, and you need a range you can set to the centimetre.
- Your balance is the weak link and a split stance has you grabbing for the wall.
- Getting out of a low chair or a car is what hurts day to day, and you want to train that exact movement.
- You like a lift you can track. The box height tells you exactly what you did last week.
Choose the lunge when
- Squats to your box are calm for 3 sets of 12 and you need more work per leg.
- One leg is clearly weaker, and in a squat the good leg quietly does the work.
- Your running, hiking or sport has you landing on one leg and pushing off it.
- A deep squat bothers your hips or back, but a short split stance does not.
Using both in one week
The squat is the main lift and the lunge comes second, on two or three days a week with a rest day between. Do 3 sets of 8 to 12 squats to your box, then 2 sets of 6 to 10 reverse lunges per side, in a range where the pain holds at its usual level or eases off. Finish with glute bridges, because the 2018 patellofemoral pain consensus backs pairing knee-focused work with hip-focused work. Score the knee from 0 to 10 before each session and again the next morning. Change one thing at a time, and a higher morning score will point at its cause.
From a high box to a full reverse lunge
- Sit to stand from a chair about 45 cm (18 in) high, 3 sets of 10 without using your hands. Two sessions in a row with a calm knee the next morning, and you move on.
- Take a firm cushion or a book off the stack to lower the box 2 to 5 cm (1 to 2 in) at a time. Depth is the dial you turn.
- Goblet squats to the lowest box that stays calm, holding a light dumbbell or a full water bottle at your chest: 3 sets of 8 to 12, each lowered over a slow count of three.
- Step-ups onto the bottom stair, 3 sets of 8 per leg. Stand up with the top leg only and come back down slowly.
- Short reverse lunges with one hand on a wall, 2 to 3 sets of 6 to 10 per leg, the back knee touching down on a cushion.
- Reverse lunges to full depth, then with dumbbells. Forward and walking lunges come last, and only if the knee stays quiet.
The numbers
- Stepping down vs stepping up
- 13.8 vs 11.2 MPaPeak kneecap stress at the same 45 degree knee bend in 20 healthy adults (Chinkulprasert 2011). Stepping down loaded it about 23% more.
- Squat range easiest on the kneecap
- 0 to 45 degreesIn 10 healthy adults a squat stressed the kneecap less than a leg extension machine up to 30 degrees of bend, and more from 60 degrees down. The authors advise squatting in the top 45 (Powers 2014).
- Knee arthritis pain with exercise
- 12 points lower out of 100Pooled from 44 trials of land-based exercise, measured straight after treatment (Fransen 2015, Cochrane review).
- Pain across an exercise programme
- 3.6 to 2.6 out of 10Average knee or hip pain in adults over 35 across 8 weeks of exercise twice a week. The flare after each session got smaller as well (Sandal 2016).
Mistakes that cost the most
- Pushing through sharp or catching pain because the plan says so. Sharp pain ends that exercise for the day. An ache that has gone by morning does not.
- Short-stepping a forward lunge. In a 2022 lab study a short step put more load on the kneecap in the deep part of the lunge than a long one.
- Changing depth, load and exercise in the same week, so a flare-up cannot be traced to anything.
- Resting the knee for weeks. Rest on its own does not rebuild the leg, and exercise is a first-line treatment for kneecap pain and for knee arthritis.
Questions people ask
Are squats or lunges better for your knees?
For most people starting with a sore knee, squats. Two legs share the load and a box caps the depth. Lunges are fine for knees too, but they put more on one knee and add a balance task, so they make a better second step. Reverse lunges come before forward ones.
Squats vs lunges for knee pain: which hurts less?
Whichever keeps the knee bend shallower. Kneecap stress climbed with depth in the lab studies. Try both over a short range and keep the one that leaves the knee no worse the next morning.
Step-ups vs lunges for bad knees: which first?
Usually step-ups. The step height fixes how far the knee bends, and you can hold a rail. A 2011 lab study also measured less kneecap stress on the way up a step than on the way down. Lunges come after.
Can you do lunges and squats with bad knees?
Usually, at the right depth and load. For kneecap pain and knee arthritis alike, exercise is where treatment starts. The exception is a knee that swells, locks or gives way, or one you hurt in a fall or a twist. Get that examined before you train it.
Sources
- Patellofemoral joint forces and stress during forward step-up, lateral step-up, and forward step-down exercisesJournal of Orthopaedic and Sports Physical Therapy, 2011
- Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercisesJournal of Orthopaedic and Sports Physical Therapy, 2014
- Patellofemoral joint kinetics while squatting with and without an external loadJournal of Orthopaedic and Sports Physical Therapy, 2002
- Patellofemoral joint loading during the forward and backward lungePhysical Therapy in Sport, 2021
- Patellofemoral Joint Loading in Forward Lunge With Step Length and Height VariationsJournal of Applied Biomechanics, 2022
- 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017British Journal of Sports Medicine, 2018
- Exercise for osteoarthritis of the knee: a Cochrane systematic reviewBritish Journal of Sports Medicine, 2015
- Pain trajectory and exercise-induced pain flares during 8 weeks of neuromuscular exercise in individuals with knee and hip painOsteoarthritis and Cartilage, 2016
Figures on this page come from the studies above or from the arithmetic shown. Read how claims are reviewed and updated in How the guides are written.