Kinesiology of Exercise
Biceps Curl With a Barbell
To describe the many biceps curl exercises and the myriad of ways in which they are executed requires a separate book. Because of the great variety of exercises possible, it is very difficult to isolate only a few that are most popular yet most effective.
The biceps curl exercise using a barbell will serve as the basic variant for proper execution of the biceps curl.
Major Muscles and Actions Involved
In the biceps curl exercise, the biceps brachii,brachialis, and brachioradialis muscles are involved in elbow joint flexion. In this action the forearm moves toward the upper arm from a fully extended position of the arm.
Sports Uses
In sports, in comparison to the triceps muscle, the biceps is a relatively minor player. The greatest value of this biceps curl variant is in pulling (lifting) actions from a straight-arm or slightly bent-arm position. It is needed in chinning, climbing a rope, rock and mountain climbing, in raising the body on various pieces of gymnastics apparatus (high bar, parallel bars, unevens), weightlifting and in various obstacle course or climbing walls.
Exercise Analysis
- When you use very heavy weights, you will have a strong tendency to lean backward and push your pelvic girdle forward to get the weight moving. You should not lean backward in this variant because doing so will overcome the resting inertia of the barbell. As a result the bar will be put into motion without strong use of the muscles involved. More importantly, leaning backward creates a tendency to bring your elbows up, which decreases the effective resistance greatly (the weight is not lifted directly against gravity).
- When your arm is straight, the angle of pull of the biceps is very weak. Almost all the force of the flexor muscles is directed to pulling the forearms into the upper arms, and only a small amount of residual force is used for rotating the forearm. However, as the forearm moves closer to the horizontal position, the angle of pull changes dramatically.
- When the angle of pull is 90 degrees (when your forearm is close to the parallel position), the entire biceps muscle is being used to lift the forearm and the weights. At this time there is no or very little stabilization force (forces that pull into the elbow).
- Because of this you are much stronger when your arms approach the 90-degree angle, and the weight that seemed heavy when your arms were straight now appears to be quite light. Thus, for maximum development of the muscle through the full range of motion, you should work it in the straight-arm and bent-arm variants.
- If you have difficulty keeping your trunk erect with your shoulders back, and elbows alongside your body, do the exercise standing with your buttocks and shoulders against a wall. This will help prevent you from throwing your hips forward or your shoulders back. In addition, try to touch the wall with your elbows as you perform the exercise. This will teach you to keep your elbows back as needed for effective execution.
- The brachioradialis muscle, in addition to being involved in elbow joint flexion, also acts as a supinator when the hand is pronated and as a pronator when the hand is supinated. Therefore, to elicit a maximal contraction of the brachioradialis, you must use a neutral grip. To do this, you must execute the exercise using dumbbells.
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