Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In


Use a New Technique To Crank Up Your Crimp Strength Without Getting Injured

Being able to hold and control crimps is one of the most useful skills you can have in your climbing arsenal.

Lock Icon

Become a member to unlock this story and receive other great perks.

Already have an Outside Account? Sign in

Outside+ Logo

Intro Offer
$3.99 / month*

  • A $500 value with everything in the Print + Digital Plan plus 25+ benefits including:
  • Member-only content on all 17 publications in the Outside network like Rock and Ice, Outside, Backpacker, Trail Runner and more
  • Annual gear guides for climbing, camping, skiing, cycling, and more
  • Gaia GPS Premium with hundreds of maps and global trail recommendations, a $39.99 value
  • Outside Learn, our new online education hub loaded with more than 2,000 videos across 450 lessons including 6 Weeks to Stronger Fingers and Strength Training for Injury Prevention
  • Premium access to Outside TV and 1,000+ hours of exclusive shows
  • Annual subscription to Outside magazine
Join Outside+

Digital + Print
Intro Offer
$2.99 / month*

  • Annual subscription to Climbing magazine, and a coffee-table edition of Ascent.
  • Access to all member-exclusive content on
  • Ad-free access to
Join Climbing

*Outside memberships are billed annually. Print subscriptions available to U.S. residents only. You may cancel your membership at anytime, but no refunds will be issued for payments already made. Upon cancellation, you will have access to your membership through the end of your paid year. More Details

Over the past 15 years, the 20 mm edge—3/4-inch, just less than one fingerpad wide for most people—has become the gold standard for finger training and finger-assessment testing. Mastering or working toward mastery of the 20mm—being able to deadhang or do a one-armed pullup on it—transfers to being able to hold and control smaller crimps and other varieties and sizes of holds as well, making it a universally useful training and sending benchmark. This has been supported by anecdotal evidence as well as research conducted by me and my team at KörperForce Human Performance and Beast Fingers Climbing.


As a climber, you already know how easy it is for a good crimp to suddenly become nearly impossible to control. Take the 20 mm edge on a 45-degree wall—while you’re holding the edge, moving your feet up can make a crimp that once had to support only 30 percent bodyweight now need to support 85 percent. Now picture a deadpoint jump to and one-handed catch of the same crimp: This would be 100 percent bodyweight, and it’s no small feat! Whether you’re bench-pressing, deadlifting, or hanging a 20 mm edge, having the strength to work with 100 percent of your bodyweight doesn’t just happen. Elite climbers we’ve tested averaged 120 to 130 percent on the 20 mm, climbing V15+! With patience and a regimented program, anyone can reach 100 percent or higher.

CASE STUDY: Jonathan Xumo’s Three-Year Journey

Everyone has a unique starting point. Jonathan Xumo came to me in November 2018 with the goal of climbing V10. At the time, he had climbed for over 10 years and had sent V7 outdoors. He started training at 50 percent bodyweight on the 20 mm edge in late 2017, and then achieved 90 percent nearly 1.5 years into consistent conditioning. Finger strength is conserved over time, given there is continued stimulus: Throughout Xumo’s progression, he maintained a steady rate of increase in finger strength of ~1.989 pounds/month. During the last three months of his nearly three-year journey, he was consistently reaching 100 percent on the 20 mm edge and had sent The Occultist (V10) in Connecticut, plus two V9s. His latest project is Krajo (V11) at the Gunks; as of press time, he was making all the moves and doing the problem in two parts.


Research from the University of London has shown that training at 70 to 80 percent of 1RM (1-rep max) elicits a significant increase in tendon force, torque transfer, and absolute strength.1 Tendons respond quickly to new weight stimulus, but they also take time to rebuild and adapt; in fact, they need to go through multiple rebuilding stages to accomodate new force loads.2 Collagen fibers provide tendons their mechanical durability and strength, and it takes no less than 30 days for collagen fibers to rebuild successfully. Heavy loads can interfere with this rebuilding time—increasing your injury risk and delaying your process.3 Hence, while the three years it took Xumo to reach 100 percent might seem like a long time, they actually represent a slow, safe, graduated approach. (Note: In more than one occurrence—including Xumo’s—we’ve seen a consistent, two to three pounds per month progression on the 20 mm edge. There appear to be three modalities: 1. skin adaptions for higher pain tolerance, 2. increased muscle recruitment of the forearms, and 3. tendon-strength development.)

Tools needed: A 20 mm edge you can attach to weights (plate, dumbbells, kettlebells, etc.) to do one-armed lifts.


Training The One-Armed Lift On The 20 mm edge

Step  1: Always Use Good Form

The one-armed 20 mm lift uses deadlift form: Stand with your feet shoulder-width or wider (left photo). Using a straight back, engage your shoulders and lift with control through your legs and engaged arm, keeping your other arm behind you (middle photo); lower back to your starting position. While grip position may vary based on your goals, to protect against injury, train the half-crimp/semi-crimp position—without your thumb (right photo).

The one-armed 20 mm lift uses deadlift form: Stand with your feet shoulder-width or wider. Photo: Beast Fingers Climbing
Using a straight back, engage your shoulders and lift with control through your legs and engaged arm, keeping your other arm behind you; lower back to your starting position Photo: Beast Fingers Climbing
While grip position may vary based on your goals, to protect against injury, train the half-crimp/semi-crimp position—without your thumb. Photo: Beast Fingers Climbing

Step 2: Find Your Max

Now we’ll find your starting point using the Rate of Perceived Effort (RPE) Scale, with 1-RPE being the easiest and 10-RPE being the hardest. First, warm up for 20 minutes with easy climbing at 3-RPE, and then take a 10- to 15-minute break. For the following tests, rest three to four minutes between sets; take as much rest as needed when attempting your 1RM.

  10 reps light weight (typically 40–60 pounds) at 2-RPE

  9 reps moderate weight at 4-RPE

  8 reps moderately heavy weight at 6-RPE

  6 reps with a heavy weight at 7-RPE

  2 reps with a heavier weight at 9-RPE

  1 rep with an increased heavier weight at 10-RPE (assuming form is OK)

Step 3: Calculate Your Training Weight

Your ideal training weight is 70 to 80 percent of your 1RM. For example, with a 1RM of 100 pounds on the 20 mm edge, your ideal range is 70–80 pounds.

Step 4: Workout Programming

Here’s a simple weekly model:

Intensity: 70 to 80 percent

Workout: 3 sets of 7 lifts each

Frequency: 2–3 days a week

Re-test 1RM: Once a month or when recovered—gauge recovery via RPE. For example, if your workout weight was 70 pounds last week at 6-RPE, but is 55 pounds this week at 6-RPE, then dedicate more time to recovery.

Jonathan Xumo’s three-year journey to 100 percent, his training represented by colors corresponding to an ever-increasing strength-to-weight ratio (Xumo’s bodyweight remained consistent throughout). Photo: Data Visualization by Jonathan Xumo


Step 1: Periodization

If you’re looking for more-advanced programming, try periodization, a structured training program that increases or decreases in intensity to let your tendons rebuild and help prevent injury. Here’s an example one-week microcycle:

Day 1: 3×10 at 6-RPE

Day 2: 4×4 at 9-RPE

Day 3: 5×3 at 4-RPE

Three to six microcycles typically comprise a mesocycle, which can be anywhere from two weeks to a few months, allowing you to safely integrate outdoor climbing days, max-hang days, and rest weeks. Finally, multiple mesocycles comprise a yearly macrocycle.

Step 2: Ice and Heat

Increasing bloodflow to the hands can help accelerate healing4 and ameliorate achy fingers. Use simple ice water and a stovetop: Alternate your hands four minutes in hot water (104° F) and then four minutes in cold water (53° F) for four rounds. (Use a 12-gallon bucket if you want to reach your elbows.)

Step 3: Eat Enough Protein

Protein comprises the tendons as well as helps produce new collagen. To maintain and develop healthy muscles and tendons, athletes need at least 0.36 to 0.45 grams of protein per pound of bodyweight per day.

Step 4: BFR Training

BFR or bloodflow-restriction training (aka KAATSU), developed in Japan over 50 years ago by Dr. Yoshiaki Sato, has been picking up traction. Its benefits are myriad: 1) You can train at a lighter load when your fingers aren’t feeling strong, and 2) It increases bloodflow, oxygen, nutrients, and hypertrophy (aka increased muscle size) to the hands, which helps accelerate recovery. Look online for protocols.

Step 5: Get Lots of Sleep

A lack of sleep is one of the worst things for your recovery—when you sleep, bloodflow to your muscles increases, bringing in fresh nutrients and oxygen. Try to get six to eight hours a night.

Developing a systematic approach toward training provides a way to modulate capacity, prevent overtraining, and reduce injury risk. Finger strength, though critical to climbing performance, is just one component to climbing hard. Combining a finger program with mental conditioning and movement training can further optimize per


1RM (1-Rep Max): The maximal weight you can lift for a single repetition with correct technique.

Absolute strength: The maximum force that your muscles, tendons, and ligaments can sustain under controlled lifting conditions.

Collagen: The main structural protein in the body’s various connective tissues; the main component of tendons.

Mechanical loading: A stress load that leads to changes in the tendon, sometimes positive like an adaptation resulting in greater tendon force, but also sometimes negative like an injury.

RPE (Rate of Perceived Effort) Scale: Used to measure the subjective intensity of exercise, with 1 being the easiest and 10 being the most difficult.

Tendon force: A measurement of external force or mechanical load applied, sustained, or generated by the tendon during human movement.

Torque transfer: The tendons’ ability to transfer force generated by the muscles to effect rotation in a hinge, pulley, or lever via the human skeletal system.

Strength gains and the menstrual cycle

Training around the menstrual cycle helps the female athlete better understand fluctuations in her performance. My solution has been to provide varied stimulus to the fingers through all phases of the cycle, as well as use a campus board to stimulate adaptions on a skeletal level, further encouraging strength gains. Most of your training gains will be during your follicular phase when progesterone is lowest. Week two into this phase, you’ll have a beneficial increase in testosterone and will feel your strongest—train hard! The testosterone helps accelerate collagen turnover and boost  tendon strength. When the luteal phase begins, force production will be lower, so focus more on recovery, stretching, nutrition, and endurance to help protect the tendons from injury.

Aman Anderson ( is a Denver-based coach and climber who develops methods, research, and products to help improve athletic performance in sport climbers.

* References: 1. 2. 3. 4.