The Inchworm: A Complete Guide From First Rep to Advanced Variations
Also called Walk Out, Worm Walk
Quick Intro
The inchworm is a full-body exercise performed by bending forward from standing, walking the hands out to a plank position, then walking the feet back in to standing.
Equipment Needed
Open floor space is the only requirement.
Why the Inchworm Matters
The inchworm asks the hamstrings (biceps femoris) to lengthen under control as the hands walk away from the feet, while the chest (pectoralis major) and front of the shoulder (anterior deltoid) support the body’s weight through the plank position and the deep core muscle (transverse abdominis) and lower back (erector spinae) keep the spine stable as the body moves between standing and horizontal.
The inchworm does three jobs in one movement. Walking the hands out lengthens the hamstrings while they are moving, which is dynamic flexibility work. The crawl out and back is ground-based locomotion of the kind animal-style movement training is built on. The whole sequence also works well as a bodyweight warm-up that touches the hamstrings, shoulders, chest and core in one continuous movement.
The inchworm is a flexibility exercise first, with muscular endurance and coordination work from combining a hamstring stretch with a plank-position hold.
When to Do It
The inchworm fits best at the start of a session, as a warm-up that stretches the hamstrings and activates the shoulders, chest and core before heavier lower or upper-body work. Doing it daily is reasonable given how light the overall demand is.
Tight hamstrings or a sensitive lower back both call for a small adjustment here:
- Tight hamstrings or lower back sensitivity. Walking the hands all the way out with straight legs can round the lower back if the hamstrings are too tight to allow it. Bending the knees slightly, or stopping the walk-out short of full extension, is the safer approach.
For most people, this is a useful way to combine a hamstring stretch with shoulder, chest and core activation in one short movement.
Getting Ready
A minute of standing toe touches and a few shoulder rolls warm up the hamstrings and shoulders before asking them to move through this longer sequence.
Keep the legs as straight as comfortable while walking the hands out. The goal is a controlled hamstring stretch combined with core and shoulder stability, not speed through the movement.
Step-by-Step Instructions
1. Starting position. Stand with the feet hip-width apart, then bend forward from the hips and place both hands on the floor.
2. The walk-out. Walk the hands forward, one at a time, until the body reaches a full plank position, keeping the legs as straight as mobility allows.
3. The walk-in. Walk the feet forward toward the hands, one small step at a time, until the body returns to a forward fold, then stand back up.
Keep the hips from sagging or piking up too high during the plank portion, since a straight line through the body keeps the core engaged through the whole sequence.
How Many, How Often
| Level | Where you’re at | What to do |
|---|---|---|
| Beginner | New to the movement | 2 to 3 sets of 5 reps, bending the knees as needed to keep the lower back flat. Resting 30 to 45 seconds between sets. |
| Intermediate | 8 reps with straight legs come easily | 3 sets of 8 reps, keeping the legs as straight as mobility allows. |
| Advanced | 10 or more reps come easily | Add a brief pause in the plank position, or move toward the harder Inchworm with Push-up, since rep count alone stops adding much new demand at this point. |
Bouncing through the movement to cover ground faster is the easiest way to make the reps look quicker while quietly skipping the controlled hamstring stretch this exercise is built around, so a slow, steady pace matters more here than how fast the walk-out finishes.
Modifications and Variations
The inchworm connects to one harder progression.
As a harder progression, Inchworm with Push-up adds a full push-up at the plank position before walking the hands back in, turning the same warm-up sequence into a strength-training combination.
Progression path: Inchworm → Inchworm with Push-up
Bending the knees during the walk-out, or stopping the hands a short distance from full plank, are reasonable ways to build hamstring flexibility before chasing a full, straight-legged range.
Common Mistakes to Avoid
Rounding the lower back to force straight legs. Pushing for a full straight-legged range before the hamstrings are ready pulls the pelvis and rounds the spine. Bending the knees slightly until flexibility improves keeps the spine in a safer position.
Letting the hips sag or pike during the plank position. A hip position that drops toward the floor or rises too high changes this from a controlled full-body movement into an unsupported one. Keeping a straight line from shoulders to heels through the plank portion preserves the core demand.
Rushing through the walk-out and walk-in. Moving quickly to finish the rep skips the hamstring stretch and shoulder stability work the movement is meant to build. Taking small, controlled steps with the hands and feet keeps the sequence doing its job.
Stopping the hand walk short of a full plank. Walking the hands out only partway avoids the shoulder and core demand of a full plank position, quietly making the exercise easier without realizing it. Walking all the way out to a full plank, even briefly, keeps the full sequence intact.
After Your Set
A set of inchworms already builds a hamstring stretch and shoulder activation directly into the movement, so very little extra is needed afterward. A gentle standing backbend, hands resting on the lower back and hips easing slightly forward, reverses the forward-folded position the spine held through every walk-out. A few slow neck rolls afterward release any tension that built up while the head stayed neutral through the plank position.
Going Deeper
What makes the inchworm worth keeping in a warm-up long term is how much it covers in one movement: a hamstring stretch, shoulder and chest activation and core bracing, without needing a separate drill for each one. Following it with a set of bodyweight squats or lunges makes good use of the hamstring flexibility this movement just opened up.
The limiting factor here is almost always hamstring flexibility rather than shoulder or core strength. Most people can hold a plank position and support their bodyweight through the walk-out without much trouble, but tight hamstrings force the knees to bend or the lower back to round to complete the range. Working on hamstring flexibility separately, outside of this exercise, tends to extend how far the walk-out can go more directly than repeating the movement alone.
Someone new to the movement typically manages 5 clean reps with bent knees within the first one to two weeks, reaching 8 to 10 reps with straight legs somewhere in the three to five week range as hamstring flexibility improves.
How to Know You’re Improving
Bent knees at the start are expected, and these numbers show the path away from needing them:
- 5 clean reps with the knees bent as needed
- 8 reps completed with the legs fully straight
- A brief pause held cleanly in the plank position without hip sag
- A comfortable first attempt at Inchworm with Push-up
How straight the legs can stay through the walk-out without the lower back rounding is the marker of hamstring flexibility improving, more than total rep count.
Muscles Worked
- Biceps Femoris (the outer hamstring at the back of the thigh, stretching as the hands walk away with the legs straight)
- Pectoralis Major (the chest muscle, supporting the body once the hands reach plank)
- Anterior Deltoid (the front of the shoulder cap, carrying the upper body through each hand step)
- Transverse Abdominis (a deep core muscle that wraps around the torso like a corset, keeping the trunk from sagging as the hands travel out)
- Erector Spinae (the lower back muscles, holding the spine in line through the walk-out)
FAQ
Why do my hamstrings feel so tight during this exercise? That’s the exercise doing exactly what it’s built for. Bending the knees slightly reduces the stretch to a manageable level while flexibility improves over time.
Is the inchworm a warm-up or a strength exercise? Both, in a light form. It stretches the hamstrings and activates the shoulders, chest and core all at once, which is why it works so well placed at the start of a session.
Do I need a plank position mastered before trying this? A brief, even shaky plank is enough to start. The walk-out and walk-in themselves build plank strength over time, so waiting for a perfect plank first isn’t necessary.
How is this different from a downward dog to plank flow? Both move between a folded and extended position, but the inchworm’s hand-walking action targets a controlled hamstring stretch specifically, while a downward dog flow emphasizes shoulder and spinal mobility through a different path.
Next in this series: Inchworm with Push-up, which adds a full push-up at the plank position to turn this warm-up into a strength combination.