Method Of Injury
Injury often occurs due to excessive loading on holds that require only one or two fingers, with one- and two-finger pockets being the primary culprits. This is often caused by the desire to generate more force by involuntarily flexing adjacent fingers, which can increase strength by up to 50% but also creates a shearing force on the bipennate lumbricals.
Sudden loading, such as from a foot slip, dynamic catch, or explosive movement, can result in an eccentric load through the hand, further increasing shearing forces and the risk of injury. However, slow, repetitive, or forceful contractions can also lead to lumbrical strain—especially if the grip position is not previously trained.
Assessment
In more severe cases, there may be hematoma (bruising) or swelling in the affected finger, potentially extending into the palm of the hand.
Since lumbrical injuries are often associated with a flexor tendon strain, it is important to test for flexor tendon damage alongside this assessment.
When testing for a lumbrical strain, it is important to introduce the position and load gradually to minimize irritation to the affected area. If you experience pain at any point during the test, it is likely a positive indication of a lumbrical strain and you should stop the test.
You likely will not experience any pain in a half crimp position nor will you experience any significant pain in a four finger drag.
Property of Lutter, C et al.
Lumbrical Shift Test
To assess for a lumbrical injury, follow these steps:
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Flex your 5th finger (pinky) and 2nd finger (index finger) while keeping your other fingers extended.
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Lightly apply pressure to the distal aspect of your non-flexed fingers.
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From this position, flex your 3rd finger (middle finger) into your palm while lightly pulling on the distal end of your 4th finger (ring finger).
If you experience pain in the palm of your hand or radiating into your forearm, you may have damage to the 3rd lumbrical.
Testing the 4th Lumbrical:
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Repeat the steps above, but this time test your 5th finger (pinky) instead.
Since the 3rd and 4th lumbricals share an attachment point on the flexor digitorum profundus tendon, it is common for both to be strained.
Understanding the Results
The stage of the testing protocol that produces pain can help estimate the severity of the injury. However, for a complete and accurate diagnosis, it is best to seek professional medical attention and consider imaging, such as an ultrasound, to confirm the extent of the damage.
Property of Hooper's Beta
Distinguishing between a lumbrical injury and injuries to the flexor digitorum tendons, interosseous muscles (dorsal and palmar), volar plate, or pulley system can be challenging. However, several simple tests can help differentiate these injuries and guide proper diagnosis. Video at 10:45
Recovery
Mobility
L-Glides
Although similar to tendon glides there is a significant difference, we only want to perform flexion and extension of the MCP joint (punching knuckles). To complete this movement we will start with a straight hand, fingers pointed towards the sky. From here we will flex the fingers down, creating an L shape. Note we only want to flex the MCP not the DIP and PIP joints.
Feather Stretch
The feather stretch is a more aggressive technique and should be approached with caution. Always perform it slowly and ensure the discomfort stays at or below a 1–2 out of 10 on your pain scale. Overstretching injured tissue can lead to further damage—less is more in this case.
Start with an open, relaxed hand. Gently flex the uninjured fingers downward. If this movement causes pain, stop and avoid the stretch for now. If it's pain-free, apply very light pressure to the injured finger using your opposite hand or a stationary object.
Tissue Mobilization (Massage)
When massaging the palm of your hand near the site of injury, adjust the pressure based on your pain response. If you experience significant discomfort, reduce the pressure accordingly. This technique can be done several times throughout the day, for up to 12 minutes per session even short sessions of 2–3 minutes can provide benefits.
Strengthening
The lumbrical muscles help balance out the push and pull of our flexor and extensor muscles, that being said to support the lumbricals we should be training these groups, which can be done in a variety of ways. Hoopers Beta suggests Iron Claws progressing to reverse curls.
Lumbrical Progressions
Lumbrical Curl
Place your hand flat on a table or solid surface. Without lifting your wrist, move your hand from a flat position into a pyramid shape by sliding the tips of your fingers into your palm while keeping your wrist down. This exercise can be performed 2–3 times per week in sets of 15–20 repetitions, with long rest periods between sets (3–4 minutes). No more than four sets should be completed per session.
Resisted L's
Progressing from the L-Glides, this variation introduces resistance using a light resistance ring, therapy putty, or even a stress ball. To perform this exercise, move from the flat hand position to the L position with your hand. Place the object between your fingers and thumb, squeeze gently, and hold the contraction for 30 seconds. Rest for 30 seconds between reps. Perform 5–10 repetitions once per day.
Farmer Pinches
Using a pinch block or similar tool, select a light load that allows you to hold for 20 seconds without experiencing pain above 1–2 out of 10. While lifting, keep your hand in the “L” shape used in previous exercises. Hold for 20 seconds with 40 seconds off for 5-10 reps per day.
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Retraining Pockets
Retraining of pockets should be slowly introduced back into your workout schedule. This exercise will start with low-intensity long-duration holds and slowly move toward more moderate intensity. While progressing make sure to manage pain, keeping it under a 2/10 during the lifts and the following day.
Protocals
Low intensity: pick a weight that will allow you to…
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Holds of 30 seconds on and 30 seconds off
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5-10 reps once a day
Low - Moderate Intensity: pick a weight that will allow you to…
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Holds of 20 seconds on 40 seconds off
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2 sets of 10 reps, twice a day
Moderate Intensity: pick a weight that will allow you to…
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Holds of 10 secs, 60-90 secs off
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1 rep for 6 sets twice a week
Once we have made it to this stage, it is alright to perform easy climbing and self-regulate the climbing style, frequency and intensity. You are NOT fully recovered at this point, and you should NOT be returning to max out climbing; slow progression back into the grades is recommended.
References
Schöffl, V., Schöffl, I., Lutter, C., & Hochholzer, T. (2022). Climbing medicine: A practical guide. Springer International Publishing Springer.
Vagy, J. (2018). Climb injury-free: A proven injury prevention and rehabilitation system. The Climbing Doctor.
Lutter, C., Schweizer, A., Schöffl, V., Römer, F., & Bayer, T. (2018). Lumbrical muscle tear: Clinical presentation, imaging findings and outcome. Journal of Hand Surgery (European Volume), 43(7), 767–775. https://doi.org/10.1177/1753193418765716