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The Relative Importance of Muscle Groups

A brief look into an exciting study from 2015. The study explores the relative importance of various muscle groups in climbing

Over the last 40 years, the level of difficulty expressed in rock climbing has increased dramatically. The popularization of bouldering, red-pointing sport routes, and competition climbing have each added to the pool of training knowledge that is passed down to the next generation.

Fingerboards, campus boards, pull-ups and stretching all seem obvious today, but without pioneering researchers to explore these areas of strength training, we would know very little about what it takes to climb at a high level. Though training has progressed far from climbing’s origin, it still lacks much of the science that more developed sports have acquired.

Though people have been completing sport-specific climbing research for decades, only in the last 10 years has research begun to take off. Today, there is a lot of opportunity for novel studies in climbing.

In 2015, the Journal of Strength and Conditioning Research published a piece titled The Relative Importance of Four Muscle Groups for Indoor Rock Climbing Performance. The article takes a look at four of the most important climbing muscle groups and determines their relative importance. This allows for athlete confidence as climbers pursue strength.

The Muscle Groups

The four muscle groups the report concerns itself with are the digit flexors, the shoulder adductors, the elbow flexors, and the lumbar flexors. The digit flexors make up a muscle group found in the forearm. These muscles flex the fingers.

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The shoulder adductors are a little less obvious, but they produce vertical lift. Some of these muscles are the latissimus dorsi, anterior deltoid, pectoralis major and lower trapezius muscles. These muscles are essential for stability and general strength.

The elbow flexors are composed of the brachialis, biceps brachii, and the brachioradialis. These are the muscles that provide for much of the climber’s power.

Finally, the lumbar flexors are the abdominal muscles. This muscle group is generally used to stabilize the spine during climbing. The group is integral to precise foot movements as well.

The Method

To determine which of these muscle groups are the most important, researchers ran a control test to see the results of 11 male climbers on a 40-degrees overhung indoor-route. It was graded 5.11b. The climbers were asked to complete as many moves possible on this route. After a control was established, the climbers were given significant rest between testing days.

On testing days, the climbers would complete pre-fatiguing workouts to tire out certain muscle groups before climbing. They would one again try to accomplish as many moves as possible on the route. These results were then compared to the control.

The Results

Of the four muscle groups chosen, only two produced significant results: the digit flexors and the elbow flexors.

It is interesting that the lumbar flexors and the shoulder adductors did not produce significant results, though these muscle groups are also much larger. That said, they do not appear nearly as important as the sharp pulling power of the arm and forearm.

Part of this is explained by the 40-degree overhang of the route. This angle would put significant stress on the arms by comparison to vertical climbing.

For this route, which would have had to have been largely composed of positive holds if it were to be 5.11b and in a 40-degree, isolated the upper and lower arm. The second  most important muscle group for this route was the elbow flexor group. Following pre-fatigue of the elbow flexors, the climbers could only reproduce 78% (+ or – 22%) of their control moves.

The most important muscle group was the digit flexors. Post-fatigue, this group completed 50% fewer moves (+ or – 18%) than the control. This value is both unsurprising, as well as shocking. By comparison to the other groups, two of which yielded insignificant results and one of which yielded relatively minor results, the digit flexors are, by this measurement, around 28% more useful than even the elbow flexors. This effectively places finger and grip strength 28% more important than power.

Implications

Perhaps what is most exciting about this study is that it reveals some of the muscles that are rarely isolated in climbing training, that could not be targeted.

In the Elbow flexors, climbers could work to exercise their brachioradialis with preacher curls and their brachialis with hammer curls.

In the digit flexors, climbers should look for ways to isolate the:

  • Flexor digitorum superficialis
  • Flexor digitorum profundus
  • Lumbricals
  • Flexor digiti minimi brevis
  • Flexor pollicis longus
  • Flexor pollicis brevis

Fortunately, these muscles are naturally used in climbing. Isolating muscles can help build strength quickly, however. Isolating those muscles most useful for climbing could allow athletes to better maximize their training sessions. Fortunately, climbing on a steep board on low-texture holds should increase the power of each of these groups. Pinches will help isolate the flexor pollicis longus and the flexor pollicis brevis.

The Relative Importance of Four Muscle Groups for Indoor Rock Climbing Performance was researched and written by Michael R. Deyhle , Hung-Sheng Hsu, Timothy J. Fairfield, Taryn L. Cadez-Schmidt, Burke A. Gurney, Christine M. Mermier.

Featured photo of Alex Johnson from an image by Matt Burbach