Kinesiology of Exercise

Wrist Curl (Wrist Flexion)

Most athletes, bodybuilders, fitness buffs, and people in general do not perform wrist strengthening exercises. However, because the wrist is involved in a great many activities and is in constant use throughout the day, it should be strengthened. This is needed to not only enhance performance, but also to prevent injury and allow you to do other activities more effectively. 

For example, stronger wrists enable you to use more weight in your exercises. Doing wrist-strengthening exercises develops the forearms much more than does holding weights in your hands when you perform other exercises. In addition, by strengthening the wrists it is possible to prevent many of the increasingly severe injuries, such as carpal tunnel syndrome (together with supination, pronation and finger exercises) which affect the general population as well as athletes. One of the best exercises to develop the wrist flexors is the wrist curl.

Major Muscles and Actions Involved

The flexor carpi ulnaris and the flexor carpi radialis muscles are involved in wrist joint flexion. In this action the palm side of the hand moves toward the forearm.

Sports Uses

Wrist joint flexion and the muscles involved are most important in almost all sports that require throwing actions. The sports include baseball, football, team handball, softball, javelin, and basketball. In the field events in track, wrist joint flexion is essential in the shot put and javelin throw. It is also very important in hitting actions such as the tennis, badminton and racquetball flat serves, smashes, and forehands, the volleyball spike, ice and field hockey hits and "throws" as in lacrosse.

Exercise Analysis

  • To be most effective, the wrist curl should be done through a full ROM. This means that you should move the weight through approximately 130-160 degrees of motion (65-80 degrees below and 65-80 degrees above the horizontal position). If you are moving the weight far less than this, you are probably using too heavy a weight and therefore not getting full shortening of the muscles. Doing the exercise in this manner for a long period of time – especially with heavy weights - may lead to a decrease in wrist joint flexibility. This in turn will lead to weaker or less effective execution of various sports skills and exercises. 
  • The flexor carpi radialis and ulnaris muscles cross both the wrist and elbow joints, and therefore have an action at each end. Because of this, in order to get a strong contraction at the wrist, your elbow must be firmly stabilized. It is also effective to stretch and tense the muscles at the elbow joint by straightening your arms. When the elbow is extended, the flexor muscle tendons become taut at the upper end.
  • For successful execution, it is important that you keep your forearms in contact with the bench at all times. Because the flexor muscles also cross the elbow joint, there is a tendency for elbow flexion, which will then bring in other muscles to raise the weight.
  • When you use dumbbells, it is important to keep the shaft of the dumbbell in a horizontal position at all times. When the wrist flexors contract, they contract to execute all their actions, and therefore you may find radial or ulna flexion occurring as you do the wrist
  • You must counteract this by bringing in the opposing muscles to neutralize any rotational action and thus get pure wrist flexion. Also, when you use a barbell, some balance is required to hold the barbell level, but with the Strength Bar, there is little need for balance.
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