Climbing Endurance and Forearm Pump

What is the pump, and which endurance matters?

The pump is a mismatch between how hard your forearms are working and how much oxygen they can use. Endurance training narrows that gap.

Climbing is grip, release, shake, grip, so intermittent endurance is the kind that counts. In a 2025 study of 307 climbers, an intermittent endurance test was the next strongest predictor of climbing ability after finger strength. The article How to train finger endurance sets out what to train and how hard.

What is critical force, and why does it organize training?

Critical force is the highest intermittent intensity you can sustain without fatigue building up. It averages about 41% of maximum in trained climbers. Above it, you drain a limited reserve that runs out in minutes; below it, you can keep going.

That gives two zones. Below it, about 30 to 40% of max, you train the aerobic capacity of the forearm and raise critical force itself. Above it, about 60 to 80% of max, you train the size of the reserve and your tolerance to fatigue. To estimate yours, see The critical force test.

How do you train the aerobic base?

With easy intermittent hangs, plus easy continuous climbing. Aerobic work and strength-endurance need different loads, so precision matters.

The aerobic endurance article uses 20 to 35% of max, 10 seconds on and 5 off, for 5 to 10 minutes per set; it should feel easy for the first two minutes. The finger endurance article uses 7 seconds on and 3 off at about 35%. Without a force sensor, pick a load you can hold continuously for a full minute with effort left over. Wall work stays the most specific and should remain the bulk. See Aerobic endurance on the hangboard.

Repeaters: how heavy should they be?

It depends on the goal, because intensity decides the outcome. In a 2022 trial of 54 climbers, repeaters at 80% of max gained strength (+12.4%) and improved endurance. Repeaters at 60% improved endurance without a significant strength gain.

The classic format is 7 seconds on, 3 off, six reps. For strength-endurance use about 75 to 80% of max, 4 to 6 sets, 3 minutes between sets. For aerobic base use about 40 to 50%, 10 to 12 reps, 3 to 5 sets, 2 minutes between sets. See Repeaters.

A related format is density hangs.

How often, and when in the week?

Build the base first: 1 to 2 sessions a week for 3 to 4 weeks, then add one interval session a week while keeping one base session. Repeaters are done twice a week for 4 to 6 weeks, then retest.

Endurance work makes you tired. Keep it away from your hardest strength and limit bouldering days, and do not put it before a climbing or strength session.

Does blood flow restriction help?

It is promising for strength with less load, but the evidence is mixed. A small 2026 pilot found low-load BFR gave similar strength gains to heavy training, but 3 of 11 climbers in the BFR group dropped out because of discomfort. Added after exhausting climbing, it did not help. Rehab is where it may add the most, with a physiotherapist.

BFR uses cuffs at measured pressure and is not suitable for everyone. Try it only with a qualified professional. See Blood flow restriction for climbers.

Train it with Entralpi

Endurance zones are percentages of your maximum, so you need to see your force. On the Entralpi plate the app shows it live and logs every rep. Its endurance test is the 4-minute all-out test with one hand, and it gives critical force; what each test measures explains the numbers.