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A-Skip / B-Skip Running Drills

Draftfunctional75%intermediate⬤ limited evidence
View FHIR resourceFHIR R4 ActivityDefinition — the interoperable form of this exercise

Positions & Range of Motion

Start
standing tall, weight on the balls of the feet, ankles dorsiflexed, arms bent ~90° at the elbows ready to drive in a running rhythm
End
one knee punched up to thigh-horizontal (~90° hip flexion) with the stance foot stamping the ground; in B-skip the raised leg then actively extends at the knee and sweeps back into hip extension (hamstring 'paw-back') to strike the ground under the hip
Range of Motion
cyclical hip flexion 0→~90° with rapid ankle plantarflexion push-off; B-skip adds terminal knee extension then active hip extension paw-back through the stance

How to Perform

High-knee running drills for running mechanics and sprint performance. A-skip emphasizes hip flexion power with rapid ground contact. B-skip adds active hamstring 'paw-back' extension. Typically introduced in mid-stage running rehabilitation after pain-free jogging.

Watch on YouTube↗

Opens a YouTube search for “A-Skip / B-Skip Running Drills”

Starting position: standing

Coaching Cues

  1. 1

    Tall posture, hot feet — knee drive pulls the hip up

    (verbal)
  2. 2

    Punch the lead knee toward the horizon

    (verbal)
  3. 3

    Stamp the foot under the hip like striking hot coals

    (verbal)
  4. 4

    Body rises tall, like a string lifts the crown

    (visual)

Evidence-Based Dosing & EMG Data

Recommended Dosing

2-3×20-30 meters, 2-3x/week as warm-up or technical drill

Muscles Involved (5)

Primary Movers

Iliopsoas— Hip flexion power — knee drive
Gluteus Maximus— B-skip: active hip extension 'paw-back'

Secondary Movers

Hamstrings (Group)— B-skip: knee extension to hip extension transition
Gastrocnemius— Ground contact plantarflexion

Stabilizers

Soleus— Ankle stability during rapid ground contact

Easier Variations ↓

1

Marching

Walk through the A-skip pattern. Knee drive without the hop.

2

A-Skip in Place

Perform stationary before moving forward.

Harder Variations ↑

1

Fast A-Skip

Increase speed while maintaining form.

2

B-Skip for Distance

Focus on active hamstring engagement and stride length.

Target Movements (4)

Hip FlexionHip Joint (Coxofemoral)
Hip ExtensionHip Joint (Coxofemoral)
Knee FlexionTibiofemoral Joint
Ankle PlantarflexionTalocrural Joint

Why This Exercise Matters

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

Running and Jogging

Goals This Helps With

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

Improve Running SpeedperformanceImprove Sprint AccelerationperformanceImprove Running EnduranceperformanceHamstring Injury Preventionprevention

Research Notes

AUDIT[low]: Plantarflexor roles are inconsistent with the near-identical a-skip-drill node: here gastrocnemius is 'secondary' and soleus only a 'stabilizer', whereas a-skip-drill lists gastrocnemius 'primary' and soleus 'secondary' — for the same rapid ground-contact push-off the calf is under-weighted here. → Harmonize the gastrocnemius/soleus roles across the two A-skip nodes; the plantarflexors are prime movers of the push-off, not stabilizers.

Evidence Sources (2)