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Straight Leg Raise

Draftstrength95%beginnerstrong evidence
View FHIR resourceFHIR R4 ActivityDefinition — the interoperable form of this exercise

Positions & Range of Motion

Start
supine, one knee locked straight, opposite leg extended and pinned to the floor, trunk quiet and pelvis level
End
straight leg lifted with heel toward the ceiling to roughly the height of the opposite bent knee, knee still locked
Range of Motion
0–~45° hip flexion with the knee held in full extension

How to Perform

Supine hip flexion with knee extended. Patient lifts leg while keeping the knee straight. Common early quad and hip flexor exercise.

Watch on YouTube

Opens a YouTube search for “Straight Leg Raise

Starting position: supine

Coaching Cues

  1. 1

    Locked knee, quiet trunk — hip flexors lift a long leg

    (verbal)
  2. 2

    Lift the heel toward the ceiling

    (verbal)
  3. 3

    Keep the opposite leg pinned to the floor

    (verbal)
  4. 4

    Both sides of the pelvis stay equally pressed down

    (tactile)

Evidence-Based Dosing & EMG Data

Recommended Dosing

3×10-15 reps per leg; progress with ankle weights

EMG Activation Data

Psoas >60% MVIC at end-range; rectus femoris 40-50% MVIC [Okubo 2021]

Muscles Involved (10)

Primary Movers

Stabilizers

Quadriceps FemorisKeeps knee extended
Transversus AbdominisSignificantly active in mid-to-late concentric phase [Okubo 2021]

Lengthened / Stretched

Hamstrings (Group)AUDIT: Straight-knee hip flexion passively stretches the hamstrings; hip flexors drive the motion.
Gluteus MaximusAUDIT: Hip flexion passively lengthens glute max as antagonist.
Biceps Femoris — Long HeadAUDIT: Hip flexion + maintained knee extension lengthens the biarticular long head of biceps femoris.
SemitendinosusAUDIT: Hip flexion + maintained knee extension lengthens semitendinosus as part of the hamstring group.
SemimembranosusAUDIT: Hip flexion + maintained knee extension lengthens semimembranosus as part of the hamstring group.

Synergists & Assistors

Tensor Fasciae LataeSynergistActive contributor during hip flexion [Hu 2011]

Easier Variations ↓

1

Short-Arc Quad

Place a roll under the knee and extend only the lower leg. Reduces hip flexor demand.

Harder Variations ↑

1

Ankle Weight SLR

Add an ankle weight (1-5 lbs) to increase resistance.

2

SLR with External Rotation

Rotate the leg outward before lifting to bias different hip flexor contributions.

Target Movements (2)

Hip FlexionHip Joint (Coxofemoral)
Knee ExtensionTibiofemoral Joint

Why This Exercise Matters

Everyday activities this exercise helps you do — essential means it directly trains the capacity the task needs:

Goals This Helps With

Rehab, performance, prevention, and mobility goals this exercise supports — essential means it's a cornerstone:

Research Notes

EMG: highest rectus femoris activity among CKC/OKC exercises [Thongduang 2022]. OKC generates higher ACL forces than CKC [Escamilla 2012]. Dosing: moderate intensity, 3x/week [Whitfield 2024]. ACL-safe since no knee flexion/extension moment.

Evidence Sources (11)