Injury and overuse of the the group of muscles and tendons around the shoulder (Rotator Cuff) is among the most common in cricket. Prevention is a simple matter of understanding.
A healthy, strong Rotator Cuff functions extremely well but as we get older the muscle and tendon tissue around this area lose some elasticity and can become damaged through repetitive use, which can cause pain and inhibit movement. Over time, the tendons wear thin and a rotator cuff tear can develop.
Six muscles connect to the humerus (arm) and scapula (shoulder blade); the deltoid, the teres major and four that make up the Rotator Cuff. These are the supraspinatus, the infraspinatus, the teres minor and the subscapularis. All with different jobs involved in moving your arm around your shoulder.
These muscles have an incredible job to do. They not only responsible for the vast range of motion of the gleno-humeral (GH) joint, making it the most mobile in the human body, but are also maintain its stability, which is particularly necessary because the socket of this ball-and-socket joint is so shallow that it provides little stability itself.
These muscles not only generate the force needed to throw but also apply a braking action. With enormous joint loads during the Deceleration Phase of throwing, the Rotator Cuff muscles prevent the entire arm from following the cricket ball thrown by keeping the hemeral head (ball) in the glenoid fossa (socket).
Understanding the mechnics of throwing
Poor mechanics and posture around the shoulder are quite often factors in any shoulder injury, causing adverse strains and stresses in the rotator cuff. Looking at the biomechanics of throwing may further help in our understanding.
6 phases of throwing
- Wind-up. The cricketer prepares the kinetic chain and builds potential energy whilst raising the centre of gravity. This phase produces minimal stress to the shoulder.
- Early cocking. The arm is bent to 90 degrees with abduction to posterior of the body. External rotation is initiated with deltoids (early) and cuff (late) initiated.
- Late cocking. Foot is planted and there is maximum external rotation (170 degrees) with peak cuff activity: Mid phase: supraspinatus, infraspinatus and teres minor. Late phase: subscapularis as the torso opens.
- Acceleration. The cricketer now rotates the shoulder to the ball release point of 90o rotation. The velocity nears 7000 deg/sec. There is eccentric to concentric conversion with minimum load to GH joint during energy transfer.
- Deceleration (Most violent): The ball is released to 0o rotation. The contraction becomes eccentric to slow the arm with posterior capsule stress.
- Follow through. The cricketer rebalances as muscles return to resting levels.
When you consider that all this takes approximately 2 seconds (1.5s for Wind Up to Late Cocking, 0.05s for Acceleration and 0.45s for Deceleration to the end), you can appreciate the stresses we continually place on this area and perhaps see how we can help prevent injury by strengthening these muscles.
How to prevent Rotator Cuff injury
There are many exercises to strengthen this area. Pulleys in the gym are excellent; by pulling the cables in all directions, all four muscles and more are worked.
There are many exercises that can easily be performed at home; dynamic exercises requiring balance should be used, such as press-ups with one hand on a medicine ball, or walking forwards/sideways in the press-up position. You can even exercise in bed!
Lying on your side with your top arm following the line of your body, your elbow bent with your forearm coming out in front, holding a suitable weight. Raise the weight to the ceiling with arm flexed and close to the body; rotating at the shoulder. Count two up and four down. This exercise activates the supraspinatus, subscapularis, infraspinatus and the deltoids.
To activate the teres minor, as well as the infraspinatus, stand or sit upright, arms outstretched to your sides with 90o elbow flexion so that weight is held in front of you. Rotate at the shoulder until the weight is raised to head level, pointing upwards. Slowly lower the weight and repeat, exercising both arms.
All the exercises possible with a pulley can be performed at home with the use of exercise/stretch bands.
Always remember to set aside enough time for a complete warm up prior to any exercise; dynamic stretching and core exercises for balance and proper biomechanics, then move on to free weight resistance training of the upper (and lower) body. Remember also to devote enough time for developmental stretches at the end of the session, whilst the muscles are sill warm, to increase your range of movement about your joints.
About the author
Liz Ward is a Strength and Conditioning Practitioner operating in and around Essex, Cambridgeshire, Hertfordshire and Suffolk with a mission to change the way cricketers train for the sport; introducing biomechanics, fitness, psychology and nutrition.
If you would like a consultation you can email Liz at firstname.lastname@example.org. Liz is also a consultant coach on the Simplycricket Fitness and Nutrition forum.© Copyright miSport Holdings Ltd 2008