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Cross Mountain Climbers

Cross mountain climbers run the knees diagonally — each knee drives under the body toward the opposite elbow while the hands hold a plank. The crossing line adds an oblique rotation the straight version lacks, packing core, shoulders, and conditioning into one floor-bound sprint. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Abs · rectus abdominis Hip flexors · iliopsoas Obliques Front shoulders · anterior deltoid Quads · quadriceps

Sets & reps by goal

GoalSets × RepsRest
Strength3 × 3–6 per side (slow, 2 s per drive)90 s
Muscle3 × 9–12 per side60 s
Endurance3 × 18–27 per side, or 30 s work / 30 s rest30–60 s

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner-accessible at slow speeds; the fast version assumes a plank that cannot be shaken.

Proper form — 5 cues

  1. Set a strong high plank — hands under shoulders, hips level, floor pushed away.
  2. Drive one knee diagonally toward the opposite elbow.
  3. Snap the legs through their exchange while the hips stay quiet and low.
  4. Keep the shoulders stacked over the wrists the entire time.
  5. Find a rhythm you can sustain — the plank must survive the speed.

Breathing: Exhale with each knee drive and keep the rhythm — breath-holding ends these sets early.

The 3 mistakes Maddy corrects most

Hips piking toward the ceiling. The high hips shorten the crossing distance, deleting the oblique work the diagonal exists for. Fix: Film one set from the side: your back should stay near-flat while the knees travel underneath.
Bouncing on the toes with tiny knee drives. The jog-in-place version raises the heart rate but leaves the trunk untouched. Fix: Make every knee genuinely cross the midline toward the opposite elbow — range first, speed second.
Shoulders drifting behind the wrists. The backward lean unloads the shoulders and turns the plank into a sagging crouch. Fix: Keep nose over fingertips; if the shoulders keep retreating, slow down or shorten the set.

Common questions

What is the difference between cross and regular mountain climbers?

The direction of the knee drive. Regular climbers pump the knees straight toward the chest — mostly hip flexors and conditioning. Crossing each knee toward the opposite elbow adds trunk rotation under a plank, which recruits the obliques hard on every rep. Same footprint and pace; meaningfully more core work per second.

Are mountain climbers cardio or core training?

Both, and the mix is up to you. Done fast in long sets, they behave like sprint conditioning that happens to involve a plank; done slowly with deliberate cross-body reaches, they become an oblique and shoulder-stability drill. Deciding which you are training before the set starts is what makes the set productive.

My wrists hurt during mountain climbers — any fixes?

Three that work: spread the fingers and grip the floor to share load across the hand, elevate the hands on a bench or step to reduce the wrist angle, or switch to fists on a mat. Building wrist tolerance gradually with shorter sets also matters — jumping into long climber sets cold is the usual culprit.

Related exercises

Easier: Mountain Climbers

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