Maximal grip : train extensor muscles !

You could read it (in french), in previous articles of La Fabrique Verticale : in climbing, during warm-up or physical training, you should pay attention to the antagonist muscles (wrist and finger extensors, arm external rotators…). Indeed, it’s necessary to avoid injuries. But, did you know that you could involve your grip strength while training forearm extensors ? This is the main result of a japanese study from year 2011, published in the European Journal of Applied Physiology.

Gripping : how does it work ?

Gripping has a complicated mechanism in which force is produced by a co-contraction of forearm flexors and extensors. Theses muscles activate simultaneously to keep the wrist stable at the optimal angle : maximal gripping force is obtained in the range of 20° to 45° extension.

One question is : what is the optimal synergy between flexors and extensors ? We mean : what is the ideal activation pattern of extensors which leads to the maximal gripping force ?

The purpose of Ryota Shimose, Atsuhiko Matsunaga and Masuo Muro (Tokyo Universities) was to investigate whether increasing forearm extensor with isometric wrist extension training has an effect on gripping force.


The devices used for testing and training


13 adult subjects participated in this study.

First step was to performed the maximal gripping force on a standard device, at different wrist angles in the direction flexion-extension. During this procedure, EMG surface activity of forearm muscles was recorded.

measurement-gripping force-wrist angle

Max gripping force and wrist angles

During second step, subjects performed the training program : five times a week during 8 weeks, training consisted of 30 repetitions of exercise (70 % maximal voluntary contraction) of wrist extension ; each exercise was held for 2 s with a 2 s interval.

Every two weeks, maximal voluntary contraction was re-evaluated to reset training intensity.


The present study shows that isometric wrist extension training leads to increasing gripping force. As forearm girth on both sides did not change, one can say that the increasing force is due to neural adaptation.

It also shows an increasing EMG activity of extensor carpi radialis and extensor carpi ulnaris and decreasing activity of flexor carpi ulnaris and flexor digitorum superficialis.

Strength gain after resistance training of short duration was induced by neural adaptation.

maximal gripping force-training-extensor-fingers

Gripping force at different wrist angles after training

After training, the gripping force/wrist angle relationship changed : the wrist angle at maximal gripping force shifted to flexion by about 9° after 8 weeks of training (from ± 34° to ± 25°) (not statistically significant).

Practical applications

The authors of this study had a therapeutical approach. From their point of view, the wrist extension training should be considered as a therapeutical training strategy to increase gripping force and help prevent forearm muscle impairment.

From a climber’s point of view, who always need to grip the holds better and better, there is a way : with only 10 minutes weekly training you can obtain significant results.


Extensor training device

You can just try to apply the protocol described : 30 isometric contraction of wrist extensors again a resistance (for instance, placing the back of your hands under a table, then apply a vertical force to the top, or with specific devices – see picture), not maximal, for 2 s effort, 2 s recovery, 3 to 5 times a week. Without neglect the warm-up ! 😉

Article : Ryota Shimose, Atsuhiko Matsunaga & Masuo Muro (2011) : Effect of sumaximal isometric wrist extension training on grip strength. Eur J Appl Physiol 111, 557-565.

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