Side Mountain Climber
- Target muscle
- —
- Equipment
- Body weight
- Body part
- Cardio
- Type
- Aerobic
The side mountain climber is a bodyweight aerobic exercise that combines the endurance demands of a cardio drill with the core stability challenge of a plank. By driving each knee laterally toward the same-side elbow rather than straight forward, it places greater emphasis on the obliques and deep core stabilizers. It fits well in conditioning circuits, warm-ups, or high-intensity interval training.
How to do the Side Mountain Climber
- 1Set up in a high plank with your hands directly under your shoulders, arms fully extended, and your body forming a straight line from head to heels.
- 2Spread your fingers slightly and press firmly through your palms to stabilize your wrists and shoulders.
- 3Brace your core, squeeze your glutes, and keep your hips level — they should not rise or sag.
- 4Drive your right knee out to the right side toward your right elbow, keeping your foot close to the floor and your hips square.
- 5Return your right foot to the starting position with control before initiating the next rep.
- 6Drive your left knee out to the left side toward your left elbow using the same controlled lateral path.
- 7Return your left foot to the starting position to complete one full rep.
- 8Continue alternating sides at a steady pace, breathing rhythmically and maintaining your plank alignment throughout the set.
Form tips
- Keep your hips level the entire set — letting them hike up shifts the load off your core and reduces the effectiveness of each knee drive.
- Exhale as you drive each knee out and inhale as you return to the plank to keep your breathing consistent and your core pressurized.
- Start at a slow, deliberate pace to nail the lateral knee path before increasing your speed; control beats momentum.
- Keep your neck neutral and gaze at the floor a few inches in front of your hands to avoid straining your cervical spine.
- Actively push the floor away with your hands throughout the set to keep your shoulder blades stable and your chest from collapsing.
Common mistakes
- Letting your hips pike upward as you drive the knee, which removes the plank demand and reduces core activation.
- Rotating your torso to get the knee closer to the elbow — this turns the movement into a twist rather than a true lateral drive and reduces oblique engagement.
- Moving too fast before mastering the lateral knee path, which causes sloppy hip position and diminishes both the cardio and core benefit.
- Allowing your hands to drift wider than shoulder-width, which destabilizes the base and can strain the shoulders over time.
- Holding your breath during the set, which causes core pressure to drop mid-rep and limits endurance output.
Frequently asked questions
What muscles does the side mountain climber work?
The side mountain climber is classified as an aerobic exercise rather than an isolated strength movement. The lateral knee drive challenges the core — particularly the obliques — while the plank position keeps the shoulders, hips, and deep stabilizers working continuously throughout the set.
What is the difference between a side mountain climber and a standard mountain climber?
In a standard mountain climber you drive the knee straight toward the chest, emphasizing the hip flexors. In the side mountain climber you drive the knee out laterally toward the same-side elbow, shifting more demand onto the obliques and lateral core stabilizers.
Is the side mountain climber good for beginners?
Yes, with some preparation. Because it uses only body weight, there is no external load to manage, but you do need enough shoulder stability and core control to hold a solid plank. Practice holding a high plank for 20–30 seconds before adding the lateral knee drives.
How many reps and sets should I do?
For cardio conditioning, aim for 3–4 sets of 20–30 total reps (10–15 per side) with 30–60 seconds of rest between sets. For HIIT, work for 30–45 seconds per set and rest for an equal or shorter duration.
What are good alternatives to the side mountain climber?
The standard mountain climber, cross-body mountain climber, and plank hip dips are close alternatives that share the plank base and core demand. If you want a standing option with a similar lateral pattern, lateral skaters or side shuffles offer comparable cardio benefit.
