Boulder 4x4s

Boulder 4x4s are a climbing conditioning drill where you climb four short boulder problems back to back before taking a real break. They train your forearms, lats, and core to keep producing force while you are pumped, and they build the shoulder control and movement skill you need to stay efficient on the wall.

To set up, pick four boulder problems at a grade you can usually finish in one try, all on the same climbing wall. Arrange them in an order that lets you step off one and start the next within a few seconds, with little walking or waiting. Chalk up before you begin so you are ready to move straight through.

Execution is simple: climb the first problem from start to finish, then immediately get on the second. Keep moving through all four problems with only the briefest pause on the ground. Those four climbs in a row count as one set. Rest four to five minutes, then repeat for four sets total.

Breathe steadily while you climb, and brace your core before you reach or step up to the next hold. To make it easier, choose slightly easier problems or allow a few more breaths between climbs. To make it harder, use more overhanging problems, but keep the holds moderate to protect your fingers.

Fault: Picking problems right at your limit and failing halfway through. Fix: Choose four problems you can complete; the point of the drill is continuous climbing, not working a hard project.

Fault: Taking long rests on the ground between problems. Fix: Treat the four climbs as one back-to-back set with minimal rest; step off one problem and start the next quickly.

Fault: Selecting very small crimps to increase the challenge. Fix: Use moderate holds, because deep pump plus small edges raises pulley risk; save the tiny crimps for low-volume sessions.

Fault: Letting your shoulders shrug and your core sag as fatigue builds. Fix: Keep your shoulder blades engaged and your ribs down, reaching with your back and midsection tight.