Can be many things, tight muscles, forward head posture, weak cervical flexors.
I would warm up the neck and shoulder girdle, stretch the associated musculature: SCM, lev. scap, traps, internal rotators, delts.
I would then perform the reciprocity shrug to ensure full ROM. (see description below)
During the set I would put the tongue in its physiological rest position against the upper palate to activate the deep cervical flexors - thus preventing the head from shooting forward off the bench
The Reciprocity Shrug (courtesy of Paul Chek)
The reciprocity principle has its roots in orthopedic rehabilitation as a means of mobilizing joints using muscle forces. The Reciprocity Shrug is used clinically to mobilize the upper thoracic spine and lower cervical spinal region. The upper thoracic spine commonly becomes restricted in people with desk jobs, exercisers that over-utilize certain machines, individuals that over-use crunches and sit-ups, and even people who squat and lunge with poor form. Restriction in the upper thoracic region is found in people with shoulder impingement syndrome, shoulder instability, brachial plexus injury, chronic neck pain and headache secondary to cervical spine dysfunction.
To perform the exercise, you need a cable machine and a dumbbell. Stand next to a cable machine with the high cable handle in your right hand and a dumbbell in your left hand The load on the cable machine need not be greater than 40% of your max and the load in the left hand should be about the same; if the load is too great, stabilizer activation will block joint mobility.
the trainee alternaties between elevation of the left shoulder and depression of the right shoulder against light resistance. Once the prescribed repetitions are completed, the opposite side is trained in the same manner. An exception may be made (when under the guidance of a skilled therapist) in that only one side is trained to achieve a specific directional mobilization of the spine for such conditions as scoliosis or sport specific muscle/joint imbalance syndromes.
Low intensities are used to facilitate mobilization of the upper thoracic spine and lower cervical spine. The repetition range is 12-20 repetitions per side. The sets vary between one and four, depending on the amount of blockage in the region. Use more sets if there is more blockage, but never use more force or resistance. One must be observant and sensitive to their body if not guided by a therapist so that the trainee can determine the appropriate load.
If too much load is used, there will be no therapeutic mobilization. If too little load is used, there may not be adequate force to encourage mobilization. The most effective way to determine if you are getting results on your own is to simply see how far you can rotate your neck before and after each set. If your cervical rotation increases after each set, you are getting the desired training response. You will also notice that in most cases, the ability to raise your arms above your head (in flexion) without restriction improves as your upper thoracic mobility improves. There should NEVER be pain during or after this exercise. If there is, decrease the load. If pain/discomfort continues, consult a sports physician or physical therapist.
Through all phases of the exercise, an attempt should be made to maintain axial alignment of the head and pelvis relative to each other The spine will move, but should move within the confines of proper head and pelvis position. Failure to do so will result in excessive movement of the body above and below the region of the upper thoracic spine and will be of little therapeutic benefit
The Reciprocity Shrug should be used at the beginning of your training session. Improving the mobility of a hypomobile upper thoracic and/or lower cervical spine will facilitate optimal function of the head/neck/shoulder complex and assist in optimal development through exercise and motor skills development.
I would finish the workout with the low cable shrug & external rotation exercises for the teres minor & infraspinatus. You could then repeat the stretches.
S
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