Analysis By Dr Paul Batman
Client Instruction
Starting Position
- Standing in an upright position grasp the dumbbells with both hands in a pronated position
Up Phase
- While maintaining slightly bent knees slowly raise your right arm forward of your body
- Keep your left arm against your left thigh
- As you are raising your right arm forward of your body contract your abdominals and spinal muscles to hold your trunk steady
Down Phase
- As your right arm approaches shoulder height pause and begin to lower your arm back to the original starting position
- Repeat the movement with your left arm
Muscle Analysis
Up Phase
Joint Action Contraction Muscle Group
Shoulder Joint Flexion Concentric Shoulder Joint Flexors
Down Phase
In the down phase of the exercise the weight is lowered slowly with gravity. The same muscles that concentrically contracted to lift the weight are the same ones that are eccentrically contracting to lower the weight.
General Kinesiological Analysis
In the front arm raise, the humerus is raised forward of the body in flexion. The clavicular portion of the pectoralis major, anterior deltoid, coracobrachialis and the biceps brachii contribute to flexion of the shoulder joint. The corresponding scapula movements are abduction and upward rotation caused by the concentric contraction of the serratus anterior, pectoralis minor and the trapezius.
The elbow joint is locked in extension by the static contraction of the triceps and the anconeus.
Advanced Kinesiological Analysis
In the up phase of the front arm raise, the prime movers are the clavicular pectoralis major and the anterior deltoid as they cause flexion of the shoulder joint. The coracobrachialis and the biceps are assisting in the exercise. The prime movers acting on the scapula
include the serratus anterior, pectoralis minor and the trapezius. The clavicular pectoralis major is a prime mover to approximately 115 degrees, which is slightly above the horizontal. It has also been suggested that for the clavicular pectoralis major to maintain a maximum contraction further weight must be added to the arm.
As the clavicular pectoralis major and the anterior deltoid flex the shoulder joint, there is an additional movement of medial rotation of the humerus that is also possible. The medial rotation is possible due to the insertion point of both the pectoralis major and the deltoid. As the muscle contracts concentrically it pulls on the bone to which it is attached. At that point it will cause all the movements that the muscles are responsible for. To prevent this medial rotation of the humerus from occurring, the infraspinatus and the teres minor contract statically to neutralize this additional movement.
In the initial movement of the scapula, the serratus anterior and pectoralis minor contract to cause abduction. For this to occur there must be a simultaneous neutralizing of their additional movements of upward and downward rotation. As the shoulder continues to flex, the scapula must move into upward rotation caused by the concentric contraction of the serratus anterior and the trapezius. When both these muscles contract in unison to cause upward rotation they neutralize the additional adduction and abduction that each will also cause.
As the shoulder joint begins the flexion movement to lift the weight, the trapezius, pectoralis minor and the rhomboids contract statically to stabilize the scapula to allow the pectoralis major, anterior deltoid and the coracobrachialis to contract from a firm base. Once the weight is lifted, the scapula begins to move into abduction. At this time the degree of stabilization of the abdominals and the spinal extensors is increased.
A variation of this exercise is the barbell front arm raise. This exercise uses the same movements at the shoulder joint and scapula, with both arms moving together simultaneously rather than each arm in isolation. It can also be performed on a low cable pulley system where the client faces away from the weight stack, grasps a bar that is attached to the low cable and while placing the cable between their legs, raises the bar forward of the body. Front arm raises can also be performed on an incline bench with dumbbells. The dumbbells can be raised forward alternatively or at the same time.
