Shoulder Exercises: How to avoid shoulder trouble - the latest research and a practical advice on achieving balanced upper-body development

Chronic shoulder pain is a common problem, and not just for athletes. Among the population at large, day-to-day activities such as DIY or gardening can produce chronic shoulder pain, as can resistance work in the gym, when enthusiasts pile on the weight without paying heed to the need for balanced strengthening. Adults beyond the age of 50 are more vulnerable in general to rotator-cuff tears, the incidence increasing with age⁽¹⁾.

Among sportspeople, a large group, known as the ‘overhead athletes’, are at increased risk of chronic shoulder pain and injuries. The overhead group covers a broad range of sports including swimming, tennis, cricket, javelin and baseball, all of which involve variations on the generic throwing action where the arm moves above the head (see box below).

The throwing movement recruits a large number of muscles and combines a large range of arm motion with high forces or speeds at the shoulder joint. All overhead athletes tend to perform many repetitions of the movement, usually with a dominant arm only, as part of their sports training.

For the shoulder and arm to move efficiently requires coordinated movement of the scapula and humerus, known as scapulohumeral rhythm. For example, arm abduction is accompanied by some upward rotation of the scapula, allowing the deltoid muscle to maintain a good length-tension relationship throughout the full 180 degrees of abduction.

Scapular and humeral coordination also involves the stabilising muscles of the scapula working in concert with the rotator-cuff stabilising muscles of the gleno-humeral joint. If the scapula holds its position correctly, the rotator cuff will do its job more effectively. Or, to put it another way, active stability is necessary to avoid excessive stress in the shoulder joint.

Get the balance right

The importance of rotator-cuff muscle strength in throwing was examined by a research team from the West Point Army Hospital in the US⁽²⁾. Scoville et al looked at the strength of normal subjects without any shoulder injury symptoms, comparing strength ratios of the end range of lateral and medial rotation.

Subjects were assessed on an isokinetic dynamometer (which measures joint strength). Full range of motion (ROM) was defined as 90 degrees of lateral rotation (forearm vertical) to 20 degrees of medial rotation (forearm 20 degrees below the horizontal). The average force produced in the last 30 degrees of each direction was assessed as end ROM.

The group average strength ratios results are as follows:

Concentric lateral rotation: concentric medial rotation (full ROM)	2:3
Concentric lateral rotation: eccentric medial rotation (end ROM)	1:2.4
Eccentric lateral rotation: concentric medial rotation (end ROM)	1.05:1

The concentric lateral rotation to eccentric medial rotation ratio of 1:2.4 suggests that the medial rotators have easily enough strength to decelerate the arm as it moves back to the cock position. The eccentric lateral rotation to concentric medial rotation ratio of 1.05:1 suggests that the lateral (external) rotators are capable of decelerating the forward motion, but only just.

The results of Scoville’s study suggest that normal adults with no shoulder pain possess sufficiently balanced strength for efficient biomechanics of throwing. But it also reveals how important it is for overhead athletes to maintain this balance of muscular strength, otherwise the lateral rotators may not be able to cope with the stronger medial rotation force, compromising the shoulder joint.

Problems tend to arise when athletes focus their training solely on the prime mover muscles, such as pectorals and deltoids, resulting in a relative weakness of the rotatorcuff and scapular stabiliser muscles. It is common practice now for overhead athletes to pay extra attention to lateral rotator strengthening. The same advice would apply to all adults who do resistance training: be sure to include shoulder exercises for the rotatorcuff and scapular stabilisers in order to develop balanced strength in the upper body.

While the Scoville study examined rotation strength alone, we have already noted above that throwing combines rotation with horizontal extension and flexion movements. The rear deltoid muscles must also therefore act eccentrically to decelerate the arm during the end range when the pectorals and anterior deltoid are working concentrically. So strengthening programmes must also pay attention to rear shoulder strength, incorporating pulling and rowing movements to balance pressing movements.

Here, again, gym-goers tend to be most unaware of the need for balanced development, typically focusing on the ‘mirror muscles’ (pectorals, deltoids and biceps) and neglecting the back. The best programme will be one that promotes strength in all muscle groups and develops a balanced physique, front and back.

What goes wrong

Recent research by Kibler and McMullen⁽³⁾ uses the concept of ‘scapular dyskinesis’: an alteration in the normal position or motion of the scapula during coupled scapulo-humeral movements. They suggest that a variety of symptoms share the same biomechanical fault – the inhibition or disorganisation of activation patterns in scapular stabilising muscles, leading to altered scapular function.

This idea is supported by research from a team from Belgium⁽⁴⁾. Cools et al investigated the timing of trapezius muscle activity during a sudden downward falling movement of the arm, comparing the performance of 39 overhead athletes with shoulder impingement against that of 30 overhead athletes with no impingement. The trapezius operates on the scapula in three sections: the lower portion depresses, the middle portion retracts, and the upper portion raises it.

Cools measured the time that the muscles took to switch on in all three parts of the trapezius and in the middle deltoid, and discovered significant differences between the two groups. Those with impingement showed a delay in muscle activation of the middle and lower trapezius – the muscles that are important for maintaining good shoulder positioning.

Another study from Cools and his team⁽⁵⁾ investigated whether 19 overhead athletes with impingement symptoms had differences in their scapular muscle force (measured by isokinetic dynamometer) and electromyographic activity on the affected and uninjured sides.

They found that the injured side showed significantly lower peak force during protraction, a significantly lower ratio of protraction to retraction force and significantly lower electromyographic activity in the lower trapezius during retraction.

Together these findings support the concept of scapular dyskinesis involving abnormal recruitment timing and strength of the trapezius muscle – specifically the lower and middle portions. These results underline the importance for injury prevention of good scapular stability in the depression and retraction movements.

Research from Germany highlighted changes in flexibility in the shoulders of overhead athletes⁽⁶⁾. Using ultrasoundbased measurement, Schmidt-Wiethoff et al found that the dominant arm in a group of pro tennis players had a significantly greater range of external rotation than the non-dominant arm, while their internal rotation showed a significant deficit relative to the non-dominant arm. Moreover, the total rotational range of motion of the dominant arm was significantly less than that of the non-dominant arm or of a control group.

Among the control group (not involved in any overhead sports), there were no significant differences in flexibility between their shoulders.

How to protect your shoulders

It would seem from the research that incorrect muscle function (developed through sport-specific demands or injury) is most evident in the lower and middle trapezius and lateral rotator-cuff muscles. From a practical viewpoint this means overhead athletes and people involved in weight training need to spend time on specific strengthening shoulder exercises to promote injury prevention and ensure balanced strength and good posture.

Step 1: equalise front and rear strength

The starting point is a balanced programme for front and rear shoulder muscle development. Opposing muscle groups must be trained equally. While shoulder exercises for the anterior shoulder and pectorals develop power, to train just these muscles will unbalance the shoulder. The better approach is to programme shoulder exercise pairs that work opposing muscles (see Table 1). Coaches and therapists should check that equal numbers of sets from each column are written into strength programmes.

Table 1: Front and rear shoulder exercise pairs

Press or push shoulder exercise	Opposing pull or row shoulder exercise
Bench press Dumbbell press Shoulder press Flyes Lateral raises	Bench pull or seated row Single arm row Lat pulldown Prone flyes or bent-over lateral raise Cable lateral pulldowns

Step 2: develop good pulling form

It is essential to perform pull or row shoulder exercises with correct technique in order to ensure that the middle trapezius, rhomboids and lower trapezius muscles are properly recruited.

For example, the lat pulldown is a popular exercise for the upper-back and rear-shoulder muscles, involving adduction of the arm. The exercise begins with the arms above the head.

During the pulldown movement the exerciser must focus on using the lower trapezius muscles to depress the scapula while the large latissimus dorsi muscles pull the elbows downwards. And during the return movement, it is important to make the lower trapezius muscle ‘keep hold’ of the scapula as the arms rise with the weight.

This recruitment creates the correct scapulo-humeral rhythm. Without correct use of the lower traps, the lat pulldown is performed in a hunched shoulder position, which promotes poor mechanics.

The same coaching principle applies to rowing exercises. These involve horizontal extension of the arm, using the strong latissimus dorsi muscles, and require concurrent scapular retraction from the middle trapezius and rhomboids.

Exercisers should focus on retracting the scapula at the same time as the elbow is pulled back and keeping the scapula retracted as the arm goes forwards with the weight on the return movement. If the scapula is not stabilised the athlete will perform the exercise in roundshouldered (kyphotic) posture, which again results in poor shoulder joint mechanics.

Step 3: isolate the rotator cuff

The small but crucial muscles of the rotator cuff should be targeted alongside the lower traps to avoid developing dysfunction or weakness. In the following four shoulder exercises, pay attention to the coaching points.

shoulder exercises 1: internal shoulder rotation

Use a resistance band or a pulley cable machine for this movement.

Muscles targeted

Subscapularis and pectoralis minor, the shoulder’s medial rotators.

Start position

• Stand with good posture, abs in and shoulders wide.
• Grasp the handle out to the side, palm facing forward.
• Tuck your elbow firmly into your side and fix an elbow angle of 90 degrees.

Movement

• Pull arm across your body.
• Finish with the palm facing into your body.
• Keep the elbow positioned close to your side to ensure the movement targets shoulder rotation alone.
• Hold upper body still, to prevent other muscles assisting the shoulder. Only your arm moves.
• Return to the start position slowly, under control, and repeat.

shoulder exercises 1: Internal shoulder rotation

shoulder exercises 2: external shoulder rotation

Use a resistance band or pulley machine.

Muscles targeted

Infraspinatus and teres minor, the shoulder’s external rotators

Start position

• Stand with good posture, abs in and shoulders wide.
• Grasp the handle with your forearm across your body, palm facing into your body.
• Hold your elbow close to your side and fix an elbow angle of 90 degrees.

Movement

• Pull the arm out and away from your body.
• Finish with the palm facing forward.
• Keep the elbow positioned close to your side to ensure the movement targets shoulder rotation alone
• Hold upper body still, to prevent other muscles assisted the shoulder. Only your arm moves.
• Return to the start position slowly, under control, and repeat.

shoulder exercises 2: external shoulder rotation

 

shoulder exercises 3: side lying raise Muscles targeted

Supraspinatus (top of the rotator cuff), assisted by the deltoid and infraspinatus. This shoulder exercise is particularly effective at recruiting rotator-cuff muscles while avoiding putting the shoulder joint through a stressful range of motion. It is therefore beneficial for those with shoulder injury.

Start position

• Lie on your side with your body straight.
• Place top arm straight so your hand lies by your hips, holding a dumbbell.
• Use your scapular muscles to pull your top shoulder into a wide position. Avoid hunched or rounded top shoulder.

Movement

• Lift the dumbbell straight up until your arm makes a 45 degree angle.
• Ensure your body does not roll or sway, only your arm moves.
• Lower the arm slowly, under control, and repeat.

shoulder exercises 3: side lying raise

shoulder exercises 4: human arrow Muscles targeted

Lower trapezius, focusing on scapular depression. This movement can take a little time to learn, so don’t expect clients to get it first time.

Start position

• Lie on your front with your arms by your sides.
• Have your palms facing up and fingers pointing towards your feet.
• Eyes look down into the floor, nose just off the ground.
• Do not lift your head, so your neck remains relaxed.
• Engage your abdominals and pelvic floor to keep your lumbar spine in place.
• Let your shoulders fall forward and rounded to the floor. Upper back starts relaxed.

Movement

• Pull your shoulder blades back and down so that your fingers slide down your side towards your feet. Feel that you are extending your arms down.
• Your upper back will extend slightly and all your muscles around your scapula will feel strong. You will feel your shoulder blades pull downwards into your back if you engage the lower traps correctly.
• Do not extend your lumbar spine and lift up off the floor. The low back should remain flat as the shoulder exercise is designed to isolate the scapular muscles. It is not a dorsal raise.
• Hold the position for 10 seconds and relax.
• Repeat 10 times.

Raphael Brandon

References

1. Milgrom C, Schaffler M, Gilbert S, van Holsbeeck M. Rotator cuff changes in asymptomatic adults. The effect of age, hand dominance and gender. J Bone Joint Surg Br. 1995 Mar; 77(2):296-8.
2. Scoville CR, Arciero RA, Taylor DC, Stoneman PD. End range eccentric antagonist/concentric agonist strength ratios: a new perspective in shoulder strength assessment. Journal of Orthopaedic Sports and Physical Therapy25(3), 1997.
3. Kibler WB, McMullen J, Scapular dyskinesis and its relation to shoulder pain. J Am Acad Orthop Surg. 2003, 11(2).
4. Cools et al. Scapular muscle recruitment patterns: trapezius muscle latency with and without impingement symptoms. Am J Sports Med. 2003, 31(4).
5. Cools et al. Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms. Br J Sports Med. 2004 38(1).
6. Schmidt-Wiethoff et al, Shoulder Rotation Characteristics in Professional Tennis Players. Int J Sports Med. 2004 Feb;25(2).