The Effects of Finger Extensor Training on Climbing Performance Compared With Traditional Flexor Training

June 11, 2026 updated by: April Henderson

The Effects of Finger Extensor Training on Climbing Performance Compared With Traditional Flexor Training: A Randomized Control Trial

The purpose of this study, is to assess climbing performance metrics that include max strength testing on a rock climbing hangboard, maximum grip strength, assessment of pain and function using the DASH (disability of the arm, shoulder and hand), and maximum flexor strength and maximum extensor strength in climbers who perform a traditional finger training protocol compared to climbers who train both traditional flexor training protocol and extensor tendons.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Hand, forearm strength, and endurance are highly important elements in elite climbers. Constant training is essential, e.g. eccentric-concentric training of finger flexors. Climbers have traditionally trained finger flexor strength for climbing performance, however to our knowledge, no formal protocol exists for training extensor tendons. In a study performed by Devise, finger flexor to extensor strength ratios were found to be 3:1 in non-climbers. In experienced or elite climbers however, the average ratio was 6:1 and as high as 9:1. Upper extremity injuries are most common in rock climbers, with finger injuries being most prevalent. Pulley injuries, consisting of rupture of the A2 or A4 annular pulleys are the most common type of injury. Other finger injuries include tenosynovitis of the flexor tendons, as well as lumbrical muscle tears. The coordinated action of flexor and extensor tendons allows for a wide range of hand movements, including grasping, gripping, and releasing objects, as well as intricate finger movements. The pulleys along the tendons (annular and cruciate) act as fulcrums, increasing the mechanical advantage of the tendons and allowing for efficient flexion. Damage to either flexor or extensor tendons can lead to significant loss of hand function. The purpose of our study, is to assess climbing performance metrics that include max strength testing on a rock climbing hangboard, maximum grip strength, assessment of pain and function using the DASH (disability of the arm, shoulder and hand), and maximum flexor strength and maximum extensor strength in climbers who perform a traditional finger training protocol compared to climbers who train both traditional flexor training protocol and extensor tendons.

Study Type

Interventional

Enrollment (Estimated)

36

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Oregon
      • Portland, Oregon, United States, 97215
        • Mazamas

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Adults aged 18 years or older
  • Recreational to advanced rock climbers as defined by the International Rock Climbing Research Association (IRCRA) scale
  • Climbing experience of at least 1-2 sessions per week for the past 6 months OR a minimum of 2 years of climbing experience
  • Ability to commit to two 45-minute training sessions per week for 6 weeks
  • Access to a hangboard or fingerboard and appropriate loading equipment
  • Ability to provide informed consent
  • Willingness to refrain from climbing the day prior to testing sessions

Exclusion Criteria:

  • Upper extremity injury (hand, wrist, elbow, or shoulder) within the past 6 months
  • Participation in a structured or organized hangboard training protocol within the past 4 months
  • Climbing less than 1-2 times per week during the past 6 months and less than 2 total years of climbing experience
  • Age under 18 years
  • Inability to safely perform maximal isometric finger flexion or extension testing
  • Inability or unwillingness to comply with the study protocol

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Maximum Flexor Strength (MFS)
Participants assigned to the Maximum Flexor Strength (MFS) group will perform a traditional finger flexor hangboard training protocol twice weekly for six weeks. Training is performed at 70% of maximal finger flexion strength using a standardized work-to-rest ratio. Participants will complete pre-, mid-, and post-intervention testing of grip strength, finger flexion strength, finger extension strength, finger endurance, and self-reported upper extremity function
Other: Traditional Hangboard Protocol
A structured finger flexor strength training protocol performed on a climbing hangboard at 70% of maximal finger flexion strength. Training consists of 5 seconds of isometric loading followed by 5 seconds of rest for 6 repetitions per set, across 6 sets with 3 minutes rest between sets. Training is performed twice weekly for six weeks following a standardized upper extremity warm-up.
Experimental: Maximum Extensor Strength (MES)
Participants assigned to the Maximum Extensor Strength (MES) group will perform a traditional finger flexor hangboard training protocol combined with a structured finger extensor training protocol twice weekly for six weeks. Extensor training is performed at 70% of maximal finger extension strength using isometric loading, and will . Participants will complete pre-, mid-, and post-intervention testing of grip strength, finger flexion strength, finger extension strength, finger endurance, and self-reported upper extremity function.
Other: Traditional Hangboard Protocol
A structured finger flexor strength training protocol performed on a climbing hangboard at 70% of maximal finger flexion strength. Training consists of 5 seconds of isometric loading followed by 5 seconds of rest for 6 repetitions per set, across 6 sets with 3 minutes rest between sets. Training is performed twice weekly for six weeks following a standardized upper extremity warm-up.
Other: Extensor Tendon Isometric Training
A structured finger extensor tendon training protocol performed at 70% of maximal finger extension strength using isometric loading. This intervention will be in addition to performing the Finger Flexor Protocol. Training consists of 30-second isometric contractions with 3 minutes of rest between sets for a total of 6 sets per hand. Training is performed twice weekly for six weeks and is completed during rest periods of the finger flexor training protocol
No Intervention: Control
Participants assigned to the control group will continue their usual climbing activities without participation in a structured finger training intervention. Participants will complete pre-, mid-, and post-testing identical to the intervention groups.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal Finger Extension Strength (MES)
Time Frame: Baseline (pre-training), 3 weeks, and 7 weeks (post-training)
Maximum isometric finger extension force for digits 2-5 measured using a VALD strain gauge system with finger loops positioned over the middle phalanx. Three 5-second trials per hand with 20 seconds rest; best of three recorded for each hand.
Baseline (pre-training), 3 weeks, and 7 weeks (post-training)
Maximal Finger Flexion Strength (MFS) on Hangboard
Time Frame: Baseline (pre-training), 3 weeks, and 7 weeks (post-training)
Maximal added load (or total load) for a 7-second hang on a 30 mm hangboard edge using a standardized half/open crimp position. Load increased until participant cannot maintain the full 7 seconds; maximal successful load recorded.
Baseline (pre-training), 3 weeks, and 7 weeks (post-training)
Finger Stamina and Endurance /Time Under Tension (TUT) at 80% of MFS
Time Frame: Baseline, 3 weeks, and 7 weeks
Stamina assessed as total time under tension while maintaining 80% of calculated maximal finger flexion strength using a Tindeq device and a 20 mm fingerblock. Endurance will be measured by calculating critical force at the completion of the test. Participants alternate 7-second work and 3-second rest cycles while attempting to maintain 80% target force for as many repetitions as possible to calculate stamina (up to 24 cycles). Critical Force will be calculated for each hand at completion of 24 cycles to measure endurance.
Baseline, 3 weeks, and 7 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Finger Flexion-to-Extension Strength Ratio
Time Frame: Baseline, 3 weeks, and 7 weeks
Ratio calculated from maximal finger flexion strength (hangboard test) divided by maximal finger extension strength (VALD test), calculated for each hand.
Baseline, 3 weeks, and 7 weeks
Disabilities of the Arm, Shoulder and Hand (DASH) Score
Time Frame: Baseline, 3 weeks, and 7 weeks

Self-reported upper extremity disability and symptoms using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, a 30-item validated instrument. Each item is scored from 1 (no difficulty/no symptoms) to 5 (unable to perform activity/severe symptoms). The final score is calculated using the standardized formula and converted to a scale ranging from 0 to 100, where:

0 = no disability

100 = most severe disability

Higher scores indicate worse upper extremity function.
Baseline, 3 weeks, and 7 weeks

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Maximal Finger Flexion and Extension Strength
Time Frame: Baseline to 7 weeks
Change from baseline to 7 weeks in maximal finger flexion strength (hangboard) and maximal finger extension strength (VALD).
Baseline to 7 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

April Henderson

Investigators

  • Principal Investigator: Chuck Ruot, PhD, Hardin-Simmons University
  • Principal Investigator: Cordelia M Mangia Jansson, MSc, KTH Royal Institute of Technology

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 11, 2025

Primary Completion (Estimated)

August 4, 2026

Study Completion (Estimated)

August 6, 2026

Study Registration Dates

First Submitted

February 11, 2026

First Submitted That Met QC Criteria

February 11, 2026

First Posted (Actual)

February 17, 2026

Study Record Updates

Last Update Posted (Actual)

June 15, 2026

Last Update Submitted That Met QC Criteria

June 11, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 202532

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared. All data are coded by participant number and stored on a secure, password-protected computer accessible only to the research team. Due to the small sample size and the potential for re-identification based on detailed performance and training data, IPD sharing is not planned. Only aggregate, de-identified results will be reported in publications and presentations.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Healthy Adult

Clinical Trials on Traditional Hangboard Protocol

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in France

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe