Side-lying hip abduction, usually called side leg raises, looks like the simplest item on a home programme. Therapists keep prescribing it because of the muscle it targets. The gluteus medius sits on the outside of the pelvis and keeps the pelvis level and the knee tracking straight every time you stand on one leg.
What the EMG studies show
EMG studies report muscle effort as a percentage of a maximal contraction. A 2009 study in the Journal of Orthopaedic and Sports Physical Therapy tested 12 rehab exercises in 21 adults. Side-lying hip abduction produced the highest gluteus medius activation, 81 percent on average, ahead of the single-limb squat (64 percent) and the lateral band walk (61 percent).
A 2012 study in the Journal of Athletic Training compared three side-lying versions in 20 distance runners, each with an ankle weight of 5 percent of body mass. Plain abduction worked the gluteus medius at about 70 percent of maximum. Turning the toes up toward the ceiling (abduction with external rotation) shifted the effort to the tensor fasciae latae (TFL), a small hip muscle that pulls on the IT band, which was most active at 71 percent. Straight abduction was the best of the three for the gluteus medius.
Why it matters for knee and hip pain
- Patellofemoral pain: weak hip abductors are common in people with pain at the front of the knee. A 2023 systematic review of 14 studies found hip strengthening improved pain and knee function in every study, and four of five trials favoured adding hip work to quadriceps work.
- Gluteal tendinopathy: pain on the outside of the hip from the gluteus medius and minimus tendons. In the LEAP trial (BMJ, 2018), 204 people had education plus an eight week abductor strengthening programme, a corticosteroid injection, or wait and see. At eight weeks, 77 percent of the exercise group reported global improvement, against 59 percent after injection and 29 percent with wait and see.
Setting up the exercise
- Lie on your side with hips and shoulders stacked, top leg straight and in line with your trunk.
- Keep the top foot neutral: ankle at 90 degrees, toes pointing straight ahead, not at the ceiling.
- Lift slowly, pause, and lower under control.
- Stop the moment your pelvis tilts or your waist joins in. The hip only abducts about 45 degrees; beyond that you are moving the trunk.
The mistake almost everyone makes
Watch your pelvis. As the set gets hard, the top hip rolls back toward the floor and the leg drifts forward. Now the leg is lifting partly in front of the body, and the hip flexors and TFL take over from the gluteus medius. Rolling back also turns the toes up, the external rotation position that favoured the TFL in the EMG study. Two fixes: do the exercise with your back against a wall so you feel any roll at once, and keep the heel of the top foot a touch behind the line of your body.
Progressing it
- Tempo first: a slower lowering phase and a pause at the top.
- A loop band around the ankles or just above the knees.
- An ankle weight. The runners' study used 5 percent of body mass; your therapist sets the load for your stage.
If your programme also includes the clamshell, see our clamshell exercise guide
Doing this exercise in a guided session
These faults are hard to feel and easy to see. In a KineTrue camera-guided session, a pelvis rolling back or a leg drifting forward is flagged as you go, and the recorded sets let your therapist check how your form held up at home.
A dull ache in the outer hip during and shortly after a set is normal. Stop and check with your therapist if you get sharp hip or groin pain, pain that is worse that night or the next morning, or if the pelvis rolls even on the first reps.