Exercise guide
Side Mountain Climber
- Intermediate
- Compound
- Timed hold
- Lower legs
- Shoulders
- Upper legs
- Waist
This dynamic variation of the mountain climber targets the obliques and rectus abdominis while building significant shoulder and tricep stability. By driving the knee to the outside of the elbow, you increase lateral core engagement and hip mobility.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Start in a high plank position with your hands placed directly under your shoulders.
- Engage your core and glutes to create a straight line from your head to your heels.
- Position your feet hip-width apart with your weight on the balls of your feet.
How to do it
- Exhale as you drive your right knee toward the outside of your right elbow, aiming to get as close to the tricep as possible.
- Inhale as you return your right foot to the starting position with control.
- Immediately repeat the movement on the left side, alternating back and forth at a steady, rhythmic tempo.
- Keep your hips low and level throughout the entire duration of the set.
Form checklist
- Keep shoulders stacked directly over the wrists to maintain stability.
- Avoid letting your lower back arch or your hips pike toward the ceiling.
- Ensure the knee travels along the outside of the body, not under the torso.
- Maintain a neutral spine by looking at a spot on the floor slightly in front of your hands.
Pro tips
- Focus on 'crunching' the side of your waist as the knee approaches the elbow to maximize oblique contraction.
- Push the floor away actively with your hands to keep the deltoids and serratus anterior fully engaged.
Make it harder
- Slow down the tempo and hold the knee-to-elbow position for 2 seconds to increase time under tension.
- Perform the movement with your hands on an unstable surface, like a BOSU ball or medicine ball, to further challenge core stability.
Frequently asked
- What muscles does the side mountain climber work?
- The side mountain climber primarily targets the abs, deltoids, and obliques, and also works the erector spinae and serratus anterior as secondary muscles.
- What equipment do you need for the side mountain climber?
- The side mountain climber requires no equipment — just your body weight.
- Is the side mountain climber good for beginners?
- The side mountain climber is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.
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