The shoulder is the most commonly injured joint in the body for regular gym goers, there are many potential reasons for this, such as the fact that the shoulder joint is very shallow with many ligaments, muscles and tendons around the joint which keep the shoulder in a stable position and to cause large movements in the humerus. Improper and/or excessive movement of the shoulder can cause pinching or compression of the tissues in the shoulder joint and lead to injury. Improper movement is often caused by muscle strength imbalances, mobility restrictions, coordination issues or instability issues. For instance, stiff lat muscles often leads to poor external rotation of the humerus, and a weak serratus anterior can lead to the shoulder blade moving excessively, both of which can lead to impingements, usually of the rotator cuff tendons or the bursa.

One of the most common and devastating injuries that can occur to the shoulder is a labrum tear, this injury is more common in those who are hypermobile which allows for excessive motion in the shoulder and tearing of the labrum, this can cause a catching feeling in the shoulder but also decrease the pressure inside the joint and decrease stability even further. 

Shoulder injuries are most prevalent in gym goers who do large amounts of overhead lifting, to prevent the incidences of shoulder injury while overhead barbell lifting it is important to retract the shoulder blades to keep the shoulder in a stable position, and the wrist, elbow and shoulder should be in a stacked alignment to distribute the load of the barbell effectively.

The first step of rehabbing from shoulder injury is to identify the cause of pain, so the correct approach can be taken to heal the injury, rather than potentially make it worse. Assessing bodily movement during exercises such as a pull up or overhead press and using a video or help from a friend and paying attention to excessive scapula movement on one or both sides can give information as to the cause of pain. Try to identify as many unique bodily movements which generate the pain, such as the elbow going behind the body when barbell squatting, and then note this down.

The second step involves assessing flexibility and mobility, two tests for this include:

• Sit cross legged with your back flat against a wall, hold a light pole like object (such as a broom) at just beyond shoulder width out in front of you with a pronated grip, keep your arms fully extended and raise your arms overhead, if you was unable to comfortably get your arms to touch the wall you likely have poor shoulder external rotation.
• Stand upright with your arms elevated in line with your shoulder, bend your elbows to 90 degrees with your palms facing outwards as if surrendering. Rotate your arm slowly downward till your palms face the ground, if you weren't able to achieve this comfortably you likely have poor shoulder internal rotation.

If a mobility restriction was identified as an issue tests must be performed to find the cause of this, there are many tests for this:

• Lay flat on your back with your hand facing the ceiling, facing the palm outwards in an internally rotated position and see how far your arm can comfortably drop your arm above your head, then perform the same exercise with your palm facing inwards in an externally rotated position. If you were able to get your arm further behind your head in the first position, you are likely suffering from tight lats and teres major muscles, as the internal rotation takes slack of these muscles and will allow for greater overhead movement. On the other hand if you didn’t see any difference between arms your mobility restriction is likely involving the joint capsule itself.
• Lay flat on your back with your hands comfortably resting on your chest, have a friend go behind you and with the palms of  their hand gently push downwards on your shoulders, if you felt tightness during this you likely have an inflexible pec minor. An inflexible pec minor can pull the scapula outwards and often leads to impingements in the shoulder joints.
• Lay flat on your back with your fingers linked behind your head as if cloud watching, allow your arms to relax as your elbow drops closer to the ground, if your elbows were unable to touch the ground, you likely are suffering from a tight pec major. The pec major attaches to the anterior part of the humerus, if it is tight it will roll the arm and shoulder joint forwards.
• Assessing thoracic spine mobility is also important, as poor thoracic spine mobility can lead to overcompensation in the shoulder joint during overhead lifting motions. Begin by taping a “+” shape on a flat surface, sit in the centre of the plus with crossed legs and face the direction in between two pieces of tape so the tape forms a V shape in front of you, hold a long cylindrical object on the front of your shoulders similar to a front squat position with a cross grip, rotate as far as you can right and then left, ideally you should be able to rotate your spine so you are in line with one of the pieces of tape, if you are nowhere near doing this or can only do it in one direction than thoracic spine mobility may be a cause of your back pain.

The third step is to test for stability. Active stability is the stability offered to joints via surrounding musculature, passive stability is the stability offered to joints via passive structures such as ligaments. The sulcus test is a popular test for passive stability in particular, sit down with your arms relaxed gently by your side have a friend pull downwards on your upper arm and if a large gap was to appear between the humerus and the top of the shoulder you likely have low levels of passive stability naturally which can often result in excessive movement in the shoulder joint, to prevent this strengthening the musculature around the joint is needed.

The fourth step is to test for muscular imbalances. Having excessively strong anterior musculature as compared to posterior musculature often leads to unwanted scapula motion and instability in the shoulder joint leading to injury. To test for this lay face down on a raised surface such as a table with your arms extended out in align with your shoulders with your palms facing the ground, have a friend push down on the back of your hand gently for 3 seconds, next perform the same test but with your hands facing towards each other but with your arms overhead as in making a Y shape, if you struggled to resist the pushing force in either position you may have a muscle imbalance. The first position tests more the strength of the middle portion of your traps while the second position tests more for the strength of the lower traps.

Weak rotator cuff muscles often leads to shoulder instability, an easy test for this is to stand with your elbows by your side and your hands in line with your elbows, keep your fists clenched and in a neutral position, as if carrying two hot cups of coffee, now have a friend gently apply pressure inwards and allow the rotator cuffs to resist this motion, if this was difficult to do on one or both side you have weak rotator cuff muscles.

The serratus anterior, along with the traps, is another muscle largely responsible for correct scapula movement, to test for weak serratus anterior hold your hand out in front of you with a clenched fist, have a friend stand behind you and push your arm down and back towards your body, if the scapula moved excessively or the upper traps shrug as compensation you likely are suffering with a weak serratus anterior. 

Following the previous four steps you have now identified the cause of your shoulder pain and it is time to start performing the appropriate exercises to begin the recovery process. In step five we work on freeing up any existing mobility issues if you have any. From step 5 all exercises are best performed on both sides even if one shoulder is fine, this is to stay in control of muscular imbalances between each shoulder.

If you are suffering upper back mobility there are some exercises to help recover from this:

• Using a soft small ball, such as a tennis ball and rolling the muscles of the mid back.
• Kneel down with a foam roller placed out in front of you with your hands in a neutral position place them on top of the foam roller at about shoulder width sit down on your heels and roll the foam roller out ahead of you and let your chest sink towards the ground, hold this position here for a while.
• In a similar way to the previous stretch you can kneel with your arms laid out on a raised surface such as a chair, lean your hips forward as you chest faces the ground to achieve a large stretch in the mid back.
• Kneel on all fours, take one hand and underneath the other slide it through with your palm facing upwards as you turn your chest out in that direction.

If you are suffering with poor lat flexibility there are some exercises to help recover from this:

• Use a foam roller to gently foam roll the lat, to do this lay on your side with your bottom arm extended in line with your body and gently foam roll the lat.
• Kneel in front of a raised object such as a chair with a light cylindrical object in your hands at about shoulder width with a supinated grip, lean forward and place both of your elbows onto the raised object, get both of your elbows as close together as possible. Sit back on your heels as you round your back to stretch the lats.
• Chin ups with an emphasis on a slow lowering phase to achieve a maximal stretch to the lats can be just as effective as stretching of the muscle.

If you are suffering with poor pec flexibility there are some exercises to help recover from this:

• Soft tissue mobilisation for the pecs can be more challenging than for most muscles, the best you can do is use a small ball and pin it to the wall with your chest and move around allowing the ball to apply pressure to your chest.
• Go to the corner of the room, facing the corner, place your palm on each wall with your forearms flat against the wall, lean forward, puffing out your chest to achieve a stretch.

If you was found to be suffering with poor shoulder internal rotation it is hard to prescribe a stretch to heal this as their are many potential causes of this issue, such as poor muscular flexibility, poor alignment of the shoulder complex (such as due to poor posture) or

tightness in the muscle capsule itself, often resulting as an adaptation from years of playing certain sports such as baseball and in this case the poor internal rotation is not an issue. If on the other hand poor internal rotation is believed to be due to tight surrounding muscles and you require greater internal rotation in the shoulder a simple stretch is the classic cross body stretch when the arm is brought across the chest and pulled on by the other arm, this stretch can be emphasised if you lean the stretched shoulder onto the wall.

Step six addresses muscular imbalances, the goal of this phase is to teach the muscle to coordinate its muscular contraction and usually hold it at the desired time to maintain shoulder health, the following exercises are best done slowly and with intermittent pauses for 10-20 reps for 2-4 sets:

• If you have weak external rotators or lower traps a great exercise requires you to stand with your elbows by your side and your hands out in front of you in line with your elbows, hold a resistance band in your hands and perform the act of external rotation.
• Another exercise for the rotator cuff challenges it in a different plane of motion, it requires you to tie a resistance band on a low object such as a very heavy dumbbell, and kneel down holding the resistance band in your hand, bring your shoulder up to in line with your body and then perform the act of shoulder external rotation, this means raising your hands overhead. This is also a good exercise to recruit the serratus anterior.
• An exercise for the mid and lower traps requires you to lay face down on a raised object such as a table, let one arm drop off the table with a light dumbbell in hand, keeping the arm straight, raise the arm up and out in line with your shoulders.
• A great exercise for the serratus anterior requires you to lay on the ground with your shoulder blades retracted, hold your arms out in front of you with your shoulders extended and your hands in a thumbs up position, perform the act of shoulder extension until your thumbs touch the ground above you, than bring your arms carefully back to the starting position. Try to pay attention to your serratus anterior stretching and contracting during this motion.
• Another great exercise for the serratus anterior requires you to lay on the ground with your elbows in line with your shoulders but flat on the ground as if surrendering with your palms up to the ceiling, bring your arms overhead than back to the starting position, by pressing the arms into the ground you decrease activation of the anterior deltoids and allow more work to be placed on the serratus anterior, alternatively this exercise can be performed while sitting cross legged against a wall.

Step seven ties in with step six although some of the exercises introduced here work the whole muscle complex with emphasis on building stability over strength, such exercises include:

• Kneel down on one leg, put your hand on your hip the side you have your knee down, the other side should hold an upturned kettlebell in front of the body, extend your arm cautiously overhead keeping the shoulder in a stable alignment and then back to the starting position, do this for about 4 sets of 15 on each side.
• The Turkish get up is another popular exercise, begin laying flat on your back, for this example we will say to hold the kettlebell in your right hand extended up in the air, for the entirety of this exercise, when ready turn your chest leftwards as you raise onto your right elbow, extend you left arm out to raise up onto your hand, bring your left leg back and go onto your knee, take your left arm of the ground and take an upright posture, stand up, than reverse this process back into the starting position. Do this exercise for about 2 sets of 5 reps on each side.

Step eight is where we return to regular training, whether that would be for a particular sport or just resistance training in the gym, but at first you should be cautious and slowly build up to the previous weights being lifted prior to the injury.