Biceps Muscles Muscle: Biceps brachii, short head Origin: At the tip of the coracoid process of the scapula. Insertion: At the radial tuberosity Function: Flexor of the elbow, strong supinator and has a weak flexion effect on the shoulder (because it is biarticular- crosses both the shoulder and elbow joints). Muscle: Biceps brachii, long head Origin: At the supraglenoid tubercle of the scapula Insertion: At the radial tuberosity Function: Flexor of the elbow, strong supinator and has a weak flexion effect on the shoulder (because it is biarticular- crosses both the shoulder and elbow joints). Muscle: Brachialis Origin: At the anterior lower half of the humerus Insertion: At the ulnar tuberosity Function: Flexor of the elbow (uniarticular), regardless of whether the arm is supinated or pronated (since the ulna does not rotate) Indications of Weakness Biceps weakness is indicated when the arm hangs excessively straight or is hyperextended. This weakness may also make it difficult to supinate the forearm when the arm is moving into flexion. Brachialis or biceps that have shortened will make full arm extension or supination difficult. This will impair strength and muscular development. Triceps strength can also decrease if the biceps has shortened and is hypertonic because of the agonist antagonist relationship. Optimal Training Principles To develop optimum size and strength of the bicep muscle group, will require a variety of barbell, dumbbell and cable exercises to work the various parts of the muscle. Straight barbells keep the arm neutral. Curling bars keep the arm slightly pronated. Dumbbells and cables allow for adjusting and maximizing supination. The preacher curl emphasizes the first part of elbow flexion. The standing barbell curl stresses the midrange of biceps flexion. The concentration curl stresses the last range of biceps flexion. Variation of these 3 ranges are essential to optimize muscle fiber stress to increase biceps size, biceps strength and biceps function through a full ROM. In any biceps curl, it is important to fully extend the arm before starting the next repetition. The prestretched position of the biceps stresses the muscle through its full ROM. Use caution to make this a controlled, gentle stretch to avoid damage to the muscle, tendon, and ligaments of the elbow joint capsule, from uncontrolled hyperextention! Keeping the elbows in front of the body, as is typical of barbell and dumbbell curls, will stress the brachialis and short head of the biceps and reduce stress on the long head of the biceps. The long head is stressed more when the arm is behind the body, as in an incline dumbbell curl, which is an excellent exercise to increase both its size and strength. Many bench-press shoulder injuries are caused by weakness in the long head of the biceps. This can be determined by a functional muscle test. Long head biceps curl: Perform regular bicep curl to full flexion and then raise the elbows to shoulder height while maximally contracting the biceps. The brachialis muscle lies between the biceps and triceps and can be seen on the outer side of the developed arm. Reverse curls with barbells, curling bars or dumbbells and Hammer curls (hands semipronated: thumbs-up) increase stress on the brachialis. The biceps is 20-30% weaker in pronation, this position will increase the size, strength and function of the brachialis. Biceps supination is best done just before the elbow is at 90 degrees of flexion during a dumbbell curl. If supination starts when the arm is at the side, the supinator muscle in the anterior elbow joint does most of the work, decreasing the stress on the biceps muscle. David Gorman states that the strength of the biceps varies with the position of the arm relative to the shoulder: Chin-up: Arm is above the shoulder: flexion strength is 183 pounds (83 kilograms) Horizontal Preacher Curl: Arm is level with the shoulder: flexion strength is 146 pounds (66 kilograms) Barbell Curl: Arm is below the shoulder: flexion strength is 115 pounds (52 kilograms) Notice that the strongest flexion strength is in the chin-up position. This is one of the better biceps exercises if the person is strong enough to pull up his or her body weight. If not, Gravitron machines or Bicep Pull Downs on the lat-machine can be used to increase size, strength and function. Dr. Jim Bell
Building Bigger Stronger Arms: Biceps
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