Tennis Elbow Injuries – Top 10 Questions

1. Have I got Tennis Elbow?

This question is answered very easily by showing you a quick test that you can take and decide for yourself whether you have Tennis Elbow.  Check out the video Tennis Elbow Symptoms – Have I Got Tennis Elbow.

However for a more thorough Professional Assessment of your elbow Click Tennis Elbow Assessment

2. How do I get Tennis Elbow pain relief?

What simple things can I do right now without any equipment or professional help to get Tennis Elbow relief?  Elbow Joint Pain Relief

3. When can I start back to sport or work with Tennis Elbow Injuries?

I have much less pain in my elbow now. It only aches after using it for a short while. When can I start back to my work as an office worker using a keyboard for most of the day? More importantly when can I return to sport and especially tennis with Tennis Elbow Injuries?   Return to Sport

4. What are the best Tennis Elbow exercises to stretch elbow?

It is essential for you to regularly stretch Tennis Elbow Injuries. Here are 2 of the best Tennis Elbow Stretches!     Tennis Elbow Lateral Epicondylitis Exercises – How to Stretch Tennis Elbow

5. Is rest a cure for Tennis Elbow Injuries?

Cure for Tennis Elbow? Is rest the best cure? Should I exercise Tennis Elbow?  For the answer to these questions Cure for Tennis Elbow

Have you taken my Extensive Professional Tennis Elbow Self-Assessment Tool?
Find out

• what type of Tennis Elbow Lateral Epicondylitis do you have
• if you are doing the correct exercises
• what underlying problems are stopping your elbow from getting better
• if your neck is causing the problem
• and many more things…..

Take the FULL ASSESSMENT at Tenis Elbow Assessment

6. What is Tennis Elbow Injury?

What structures are involved? Why do I get pain from my elbow tendinitis? Is it inflammation causing the pain?
Find the answers here at Tennis Elbow Injury – What is Tennis Elbow?

7. How did I get Tenis Elbow / Lateral Epicondylits?

Does Tennis actually cause Tennis elbow? Why do I get Tennis Elbow arm pain after DIY around the house?What actually causes Tennis Elbow? Some of the answers are here Arm Pain – How Did I Get Tennis Elbow?

8. Do I need an injection for my Tennis Elbow?

When should I consider an injection? What types of injection are available?
Can you really Botox an elbow? Discover the answers at Treatment Tennis Elbow

9. Do I need surgery for my Tennis Elbow?

When do I need elbow surgery? What kind of elbow surgery is there? Is one elbow surgery better than the others?
See Elbow Surgery for Tennis Elbow

10. What is the best Tennis Elbow Brace? What type of Tennis Elbow Strap do I need?

For a customer review of Tennis Elbow Supports see Elbow Strap – What is the Best Tennis Elbow Brace?

Have you taken my Extensive Professional Tennis Elbow Self-Assessment Tool?
Find out

• what type of Tennis Elbow Lateral Epicondylitis do you have
• if you are doing the correct exercises
• what underlying problems are stopping your elbow from getting better
• if your neck is causing the problem
• and many more things…..

Take the FULL ASSESSMENT at Tennis Elbow Assessment

Tennis Elbow Tendinitis and Tennis Elbow Tendonitis – What is the Difference?

Tendinitis or Tendonitis are alternative spellings of the same condition. The -itis part means inflammation so the term tendonitis means inflammation of a tendon.
In medicine and medical textbooks you are more likely to see Tendinitis than Tendonitis although they are interchangeable.
However in Tennis Elbow Tendinitis there is generally no inflammation present and the more correct term is Tendinosis or Tendinopathy!

Tennis Elbow Tendonitis / Tendinitis Causes

Changes in the tendon are caused by repetitive movements or overuse of the muscle and tendon unit. Any activity that involves forceful gripping and / or quick repeated movements of the hand can lead to these changes and Tennis Elbow Tendonitis injuries and symptoms.

As I explained in Tennis Elbow Injury and Tennis Elbow Symptoms Tennis Elbow Tendonitis or Lateral Epicondylitis is pain in the outer aspect of your elbow and forearm and is generally not inflammatory but consists of degenerative changes in the structure of the Extensor Carpi Radialis Brevis (ECRB) or “Tennis Elbow Tendon.”

Taking part in a new activity which uses your arm, or doing more than usual of an activity can cause Tennis Elbow arm pain. Common examples are:

• tennis and racquet sports
• painting and decorating
• using handtools – saw, screwdriver, hammer etc
• using powertools – drills, sanders etc
• using a keyboard or mouse
• watersports involving gripping – waterskiing, sailboarding etc
• prolonged intricate movements of the hand – sewing, scissors, using a knife etc
• playing with the Wii games console too long

Wrist Extension Causes Tennis Elbow Injury

If I stick with tennis for the moment. Between 40 and 50% of all tennis players have experienced Tennis Elbow Tendonitis pain at least once, and for many it can persist for a long time and affect their participation in their sport.
Gripping any object involves extending the wrist (see picture above).
Resisting movements that cause the wrist to flex away from this extended position produce stress in the muscle and tendon and cause arm pain.
The classic example is a single-handed backhand in tennis – look at the forces involved in trying to ‘break’ the wrist in this picture.
These forces depend on various factors such as ball speed, speed of the racket, racket size, string stiffness, off-center impact and hand grip force.
Eccentric contraction forces in ECRB at ball impact are increased by bending the wrist and having low muscle activation.
This is exactly what is found in novice tennis players who are more prone to Tennis Elbow Tendonitis probably due to poor technique (and incorrect muscle activation) with the backhand and service strokes. It is this lack of correct muscle activation that results in increased force transmission to the ECRB tendon (lateral epicondylitis muscles) and can lead to microtrauma and degeneration in the tendon (acute Tennis Elbow).

DIY Causes of Tennis Elbow Arm Pain

Again gripping too tightly and trying to get too much done especially when your are not accustomed to doing the task for a long period can lead to overuse of the ECRB tendon and tennis elbow tendinitis pain.

When you use any tool (power tool or hand tool) you need to keep control of where it is pointing and absorb any vibrations – this is done at the wrist.
Using a screwdriver involves supination and pronation movements of the forearm while maintaining an extended wrist which stresses the wrist extensors.
Using a paint brush can involve thousands of repeated flexion / extension movements at the wrist if you are inexperienced and use bad technique and this leads to overuse Tennis Elbow arm pain.

Mouse & Keyboard and Tennis Elbow PC Pain

Prolonged use of a keyboard and / or mouse can lead to Tennis Elbow injuries. This is especially true if the keyboard or mouse is not set up for ‘ergonomic’ use. If the position of the keyboard or mouse means that the wrists are extended or flexed for any period of time then this leads to an increased stress on the forearm tendons at the elbow and produces Elbow Tendinitis pain.
In the same way, reaching out for the mouse or the keyboard can also cause arm pain.
Adjust the height of your keyboard so that you keep your forearms parallel to the floor.

Wii and Tennis Elbow Tendonitis

see my article

Summary

There is no substitute for good technique – get a good coach!
Do not grip too tightly!
Learn how to use the tools properly!

Have you taken my Extensive Professional Tennis Elbow Self-Assessment Tool?
Find out

• what type of Tennis Elbow Lateral Epicondylitis do you have
• if you are doing the correct exercises
• what underlying problems are stopping your elbow from getting better
• if your neck is causing the problem
• and many more things…..

Take the FULL ASSESSMENT at Tenis Elbow Assessment

Back to Tennis Elbow Top 10 Questions

It is essential to stretch your extensor muscles if they have shortened and also to help prevent them shortening. A quick check for shortening of the tennis elbow muscles is to hold your arm out – the elbow must be straight – and then bend your wrist and compare how far it bends with the other side.
If there is a difference between the two sides then you need to start an Elbow Exercise stretching program to lengthen the muscles.

As described earlier when tissues get inflamed, chronically irritated or become degenerate they can lay down excessive scar tissue and the tennis elbow muscles react by shortening. This leads to abnormal stresses and strains in the muscle and its tendon and can perpetuate the problem of tennis elbow.
It is essential to do your Best Tennis Elbow Stretch Exercise to stretch the muscle at least 2-3 times each day.

These are the Best Tennis Elbow Lateral Epicondylitis Exercises to stretch out your Tennis Elbow Muscles.
I much prefer the method shown in this video – you can accurately compare the two sides by how far forward you can take your wrist.
This is the technique I recommend you use to stretch out your tennis elbow muscles at least 2-3 times a day.
Initially aim to hold each stretch for at least 10-15 seconds and repeat 4 times.
It is possible to hold the stretch for 30 seconds with practice.
Rest for at least 10 seconds between each stretch.


Start with the wrist back and, as it gets easier move the wrist forwards to increase the stretch.
Aim to get as far forward as the other side with no pain.

Have you taken my Extensive Professional Tennis Elbow Self-Assessment Tool?
Find out

• what type of Tennis Elbow you have
• if you are doing the correct exercises
• what underlying problems are stopping your elbow from getting better
• if your neck is causing the problem
• and many more things…..

Take the FULL ASSESSMENT at Tennis Elbow Assessment

Back to Tennis Elbow Top 10 Questions

Tennis Elbow Injury

It is thought that an Acute Tennis Elbow injury consists of microscopic tears in the attachment of the Extensor Carpi Radialis Brevis muscle to the bone.
This tearing results in the stimulation of the repair process which increases collagen production and new blood vessel growth.
This increase in blood vessels may explain the Tennis Elbow symptoms as well as a local increase in temperature.

Tennis Elbow Symptoms

In the past it was thought that Tennis Elbow Symptoms were a result of a local inflammatory reaction. However it is now more commonly thought that even acute tendinitis is due to a sudden increase in stress which causes further aggravation of an already degenerated area of tendon.
The thinking is that the elbow symptoms are produced by the new blood vessels and their nerves at the repair site rather than from a local inflammatory response.
That is why it is considered more correct to name Tennis Elbow Injury as Lateral Epicondylosis

Lateral Epicondylitis / Lateral Epicondylosis

These are the medical names that you may see for Tennis Elbow.
Epicondylitis – the “itis” indicates that there is acute inflammation taking place (think of Appendicitis).
Epicondylosis – the “osis” refers to a more chronic and degenerative condition.

Both these terms refer to the Lateral Epicondyle which is a raised area of bone on the upper arm bone or Humerus. If you look at the diagram of the back of the right arm opposite you can see that the lower end of the Humerus widens out to form the upper portion of the Elbow joint.
There are two epicondyles one on the inside (medial – labelled A) and one on the outside (lateral – B).

The lateral epicondyle is where the Tennis Elbow muscles (Extensor Carpi Radialis Brevis, Extensor Digitorum and possibly Supinator) attach.
The Extensor Carpi Radialis Brevis muscle is the main culprit in Tennis Elbow.
It is degeneration of the tendon attachment to the Lateral Epicondyle that causes the pain and disability.

Extensor Carpi Radialis Brevis

This muscle has its upper attachment to the Lateral Epicondyle, (B in the diagram), the Radial Ligament and surrounding tissues.

It passes down the forearm deep to the Extensor Carpi Radialis Longus and Extensor Digitorum muscles and lies under the skin in the lower half of the forearm (M in the diagram opposite).

The muscle becomes tendon in the lower forearm and the tendon crosses the wrist and attaches to the base of the 2nd and 3rd Metacarpal bones in the hand (I in the diagram).

The action of the muscle is to help to extend the wrist and deviate it towards the thumb side. (Extension and Radial Deviation)

Summary

You now understand:-

• that Tennis Elbow is micro-tears in Extensor Carpi Radialis Brevis tendon
• that Lateral Epicondylitis and Epicondylosis are the same as Tennis Elbow
• where the Lateral Epicondyle is on the Humerus
• where Extensor Carpi Radialis Brevis attaches and its actions

For more information see Tennis Elbow – Get to Grips

COMING SOON!

ELBOW AND FOREARM ASSESSMENT TOOL

Back to Tennis Elbow Top 10 Questions

We have to accept that generally with sport we are going to have some sort of injury problems.
With Elbow and Forearm pain and a sport (or job) that involves repetitive gripping there is always a problem with deciding on when to restart activity and return to sport or work.
Go back too soon and the injury flares up again.
Take an extra few weeks off and you have missed out on training and preparing for a competition and also you lose conditioning and your competitive edge!

When do I return to sport?

When the test in the Video below does not cause significant pain. (Less than a 4 on a scale of 1 -10)

You have full range of elbow movement.

VIDEO TEST
TENNIS ELBOW

Ladies I want you to use a water bottle with 1 litre of water in it (just over 2 pints in US) .
Gentlemen I want you to use a water bottle with 2 litres of water in it (around 4.25 pints in US).

Grasp the towel as I do in the video and repeat 3 repetitions.
Does this significantly increase the pain in your forearm? (Greater than a “4″)

If YES then you are not ready to restart aggravating activities yet – so no return to sport.

If NO then:-
Gradually re-introduce activities which could aggravate your pain.
TENNIS – start with forehands etc and avoid backhands for a few sessions.
WORK – lift with ‘palms up’, grip hand tools more lightly, avoid ‘heavy jobs’, take regular breaks.
GENERAL – try to use the “Hook Grip” as much as possible when carrying or gripping.

COMING SOON!

ELBOW AND FOREARM ASSESSMENT TOOL

Back to Tennis Elbow Top 10 Questions

Tennis Elbow Symptoms

Common questions are

• Where do you get Tennis Elbow Symptoms?
• What are the Symptoms of Tennis Elbow
• I have a painful elbow – do I have Tennis Elbow?
• Do Tennis Elbow Symptoms spread down the arm towards the wrist?
• The pain spreads up my arm do I have Tennis Elbow?
• I have pins and needles in my arm. Is that Tennis elbow?

So, What are Tennis Elbow Symptoms

Tennis Elbow symptoms sometimes can be difficult for even an experienced practitioner to diagnose.
There are many structures that can refer pain into the elbow area.
Over the years I have seen many patients who have been given a wrong diagnosis of Tennis Elbow.
Just because you have some or all of the following Tennis Elbow symptoms:

1. pain on the outside of the elbow and possibly also down forearm
2. pain made worse by using hand especially gripping tasks
3. ‘weak’ wrist when shaking hands or turning a door handle
4. outer elbow is painful to the touch

…………………it does not mean that you have Tennis Elbow.


The symptoms of Tennis elbow can be coming from

• the joints in your neck,
• the muscles around your neck or shoulder,
• a trapped nerve in your neck
• tension on a nerve in the shoulder or upper arm
• possible fracture or stress fracture around the elbow
• a loose body in the elbow joint
• arthritis within the elbow joint

Tennis Elbow / Lateral Epicondylitis / Lateral Epicondylosis

These are essentially all the same thing.
If you answer yes to my question in the Video above then you have at least some form of Tennis Elbow.

Even if you have Tennis Elbow Lateral Epicondylitis there may be several possible complicating factors which affect what exercises you need to be doing to get better.

Find out for sure …

Take my FREE ELBOW VIDEO ASSESSMENT TOOL (Click Link)

View a quick tour of the assessment in the video – just click to play.

Back to Tennis Elbow Top 10 Questions

Tennis Elbow pain is very easily aggravated by Pull Ups.
There are a few reasons:

• gripping bar too tightly
• overhand grip
• wide grip

I will explain each of these

Gripping Too Tightly

Tennis Elbow or Lateral Epicondylitis is caused by over-use of the muscles that position the wrist to allow a strong grip, see Tennis Elbow – Get to Grips! if you have not already read it.
The harder you grip the greater the stress on the wrist extensor muscles – the more you aggravate the problem!

Overhand Grip

With an overhand grip there is a tendency to further extend the wrist to move your chin away from the bar. Also in this position the Brachioradialis muscle is used to help bend the elbow. This muscle has an attachment very close the Tennis Elbow muscles and they are recruited to help flex the elbow – remember that they cross the elbow joint see Essential Anatomy of Forearm Muscles

Wide Grip

A wide grip pulls the wrist into radial deviation as you perform your pull up. The main muscles that do this are Extensor Carpi Radialis Longus and Brevis. The Brevis muscle is the main culprit in causing most Tennis Elbow pain! So you can see why it is not too smart to work it excessively if you want your elbow pain to settle.

How Not to Aggravate Your Tennis Elbow Pain

Hook Grip

Use a ‘hook grip’ on the bar. This involves using the ends of your fingers to grasp the bar rather than making a fist around the bar and squeezing.
This relaxes the wrist joint and take the stress of the wrist extensors – relieving the aggravation.

Narrower Grip

Moving the hands in from the wide position reduces the pull of the Flexor Carpi Radialis muscles again easing the stress.

Underhand Grip

Using an underhand technique makes it possible to perform some pull ups when your Tennis Elbow is severe. I know that it works your Lats differently and that you use your Biceps more but it’s better than doing nothing or aggravating your elbow to the extent that you can’t do other weights!
Even better use an underhand grip with a ‘hook grip’

Good Technique

Make sure that the prime movers of the exercise are your back muscles and not your arms!!

The tips should allow you to train around Tennis Elbow – even better take my “Elbow and Forearm Assessment Tool” and cure your elbow!

Now in Summary Click & Watch the Video Below

Are you sure you have Epicondylitis?

Find out here!

Posterior view of left Humerus

EPICONDYLITIS EPICONDYLOSIS

Epicondylitis – means inflammation of the epicondyle or the structures attached to it. Epicondylosis is probably the more correct term to use as the condition is more often longstanding and this involves degenerative changes in the structures involved.

At the elbow you have two epicondyles one on the inner aspect of the lower humerus – the medial epicondyle (A in fig 1) and one on the outer aspect of the lower humerus the lateral epicondyle (B)

An epicondyle is an bony prominence near the “knuckle end” or rounded surface of the bone that forms the joint. It is there simply to make it easier for muscles or ligaments to attach close to the joint. An epicondyle is a raised bump of bone which has a greater surface area than a flat area of bone so generally you will find several muscles attached to an epicondyle because there is more space.

To control your elbow you actually have 16 muscles which cross the joint. There are four or sometimes five muscles that attach to the lateral epicondyle and four that attach to the medial epicondyle.

Lateral Epicondyle of Left Elbow

ELBOW LATERAL EPICONDYLITIS

In Elbow Lateral Epicondylitis it is the tendon of muscles on the outer elbow that may become inflamed or more likely undergo degenerative changes (generally through overuse or excessive strain) and painful whenever you use them.

The main muscles that attach to the lateral epicondyle are called :-

Extensor Carpi Radialis Brevis & Extensor Digitorum

TENNIS ELBOW LATERAL EPICONDYLITIS

Tenis elbow and lateral epicondylitis are one and the same thing with possible inflammation of the elbow tendons in the acute case, and more commonly, degeneration of the small tendons that connect these muscles to the lateral epicondyle. Tennis Elbow injuries are caused by repeated gripping tasks like DIY jobs and hitting numerous backhand volleys with bad technique. Also recently a very common cause of Tennis Elbow injury is playing the Nintendo Wii for hours. See my post on Wii Elbow.

REFERRED PAIN FROM NECK AND SHOULDER

Irritation of of the nerves in your neck from a disc bulge or some joint inflammation can cause pain to travel down your arm to the elbow and can feel like and present as Tennis Elbow.

Inflammation of soft tissues around the shoulder joint can refer pain down the arm to the elbow which can complicate the diagnosis of Tennis Elbow.

In addition there are a few sites in the arm where one of the the main nerves – the Radial Nerve – can get trapped or irritated and this specifically can replicate the pain and signs of Tennis Elbow!

Are you still sure you have Tennis Elbow?

Take my comprehensive FREE Assessment Tool HERE!

TENNIS ELBOW MUSCLES

These muscles are involved primarily in movements of the wrist and hand, but as they are attached to the humerus they cross both the wrist and elbow joints. In the body the muscles most susceptible to injury generally cross more than one joint. Think of the most common muscles to get injured and you get Hamstrings, Calf, Biceps etc – they all cross more than one joint.

The muscles attached to the lateral epicondyle are

1. Extensor Carpi Radialis Brevis
2. Extensor Digitorum
3. Supinator
4. Extensor Carpi Ulnaris

For More Information – see ESSENTIAL ANATOMY OF FOREARM MUSCLES 

or

TENNIS ELBOW – YOUR TOP 10 QUESTIONS ANSWERED

I want you to understand what Tennis Elbow actually affects, what you need to understand about the condition and then work out for yourself what you can do about it (that’s the DIY bit in DiyInjuryRehab.com).

You’ve probably read it all before about Tennis Elbow being an overuse injury that is caused by repetitive gripping tasks such as using a screwdriver or using power tools, that it affects between 1 and 4% of the population and that 30-40% of tennis players actually do get it!!

Well it’s all true! But I would like to take a slightly different approach. I am going to educate you to fix yourself!

Tennis Elbow can be quite persistent and can be troublesome for anything up to two years. It can become severe and in some cases requires surgery to resolve it! In 75% of cases it affects the elbow on the dominant hand side and this has serious implications for work and sport. It is important to get to grips with Tennis Elbow in the early stages and prevent it from becoming severe and chronic.

These posts on Tennis Elbow will help you understand what the condition involves and what you can do about it now to resolve it.
This post will explain:-

• anatomy of the elbow
• how the elbow moves
• what is tennis elbow?
• what causes tennis elbow?

Elbow Anatomy

There are three bones that make up your elbow joint.

First there’s the upper arm bone called the humerus which runs from your shoulder to your elbow.

Joining with the humerus at the elbow joint are the two forearm bones called the radius and the ulna.
If you stand with your arms by your sides and your palms facing forwards the ulna is the bone on the ‘inside’ nearest to your body.
It forms a ‘hinge’ joint with the humerus.

The radius lies on the outside of your forearm and has a button-like end which takes part in the elbow hinge.
It is also involved with palm up and palm down rotation of the forearm. (Pronation and Supination)

The radius and ulna are joined to each other just below the elbow and also just above the wrist joint.
These joints allow the radius to rotate around the ulna which stays stationary.
To demonstrate this bend your elbow to a right angle with your palm facing up – in this position the radius lies on the outside of the ulna at the elbow and the wrist.
Now if you turn your palm to face downwards the radius crosses over the ulna and now it is on the inside at the wrist (but still the outside at the elbow).
Click on the video for a demonstration.

If you feel the outside of your elbow you will find a distinctly sharp bony prominence which sticks out – this is called the lateral epicondyle. It is the lower part of your humerus bone. If you keep your finger on this bony lump and waggle fingers your will feel the muscles attached to this bump moving under your finger. 

Elbow Movements

As you can see from the video clip above the elbow movements are quite simple.

Flexion is bending of the elbow
Extension is straightening of the elbow
Pronation is when the palm faces down
Supination when the palm of the hand faces up

However none of the muscles that are used to produce these elbow movements are directly involved in Tennis Elbow.

What Is Tennis ELlbow?

It is thought that Acute Tennis Elbow consists of microscopic tears in the attachment of the muscle to the bone.
This tearing results in the stimulation of the repair process which increases collagen production and blood vessel growth.
This increase in blood vessels may explain the pain that is felt as well as a local increase in temperature.

However is is more commonly thought that even acute tendinitis is due to a sudden increase in stress which causes further problems for an already degenerated area of tendon.
The thinking is that the pain is produced by the new blood vessels and nerves at the repair site rather than from a local inflammatory response.

A key feature of chronic inflammation and degenerative changes is collagen production.
If too much collagen is formed, this can lead to a condition known as fibrosis.
As stated above collagen is necessary to replace the tissue lost during long term inflammation or degeneration, however the overproduction of collagen over time can lead to excessive scarring and functional shortening of the muscle interfering with it’s function.
In addition when your elbow is painful for a period of time the your brain adapts and you start to use the muscles in the arm differently and this can lead to problems elsewhere in the arm and neck.
These problems may well have to be corrected before you can use your elbow efficiently again and get rid of your pain – so it is always advisable to be assessed by a good physiotherapist (or other specialist) if you have chronic elbow pain.

Tennis Elbow Causes?

So you may be wondering why most tennis elbow pain seems to associated with gripping – you know that using a screwdriver, stripping wallpaper or practising a tennis backhand aggravates your pain. Well the reason takes a bit of explaining. 
The muscles that attach to the lateral epicondyle all are attached to the bones of the hand and they produce movements at the wrist and hand.

Movements at wrist:

      extension,                         flexion,                       radial deviation,             ulnar deviation.

The muscles associated with Tennis Elbow all produce extension of the wrist, and at least one from the group helps produce radial deviation, and one ulnar deviation.

To grip strongly you need to extend your wrist – this extension gives the muscles on the front of your forearm what is known as a mechanical advantage when producing gripping power.
Try gripping with your wrist fully flexed then the try again with your wrist extended.
It is much easier to generate power with your wrist extended isn’t it!
So although you don’t use the muscles on the back of your forearm to directly produce the grip strength in your hand you use them to help the muscles on the front of your forearm generate the power by positioning the wrist. 

I mentioned earlier that the muscles in the body that cross more than one joint are the ones most susceptible to injury. The simplest explanation for this is opposing movements can be simultaneously taking place at the two joints the muscle crosses.
This places complex movement patterns on the muscle which tries to do two things at the same time which makes it more prone to injury.
In the case of the Tennis Elbow muscles they are positioning the wrist and hand to allow you to get a strong grip- imagine using a screwdriver.
However at the same time you are frequently moving your elbow joint – remember these muscles are attached on the upper side of the elbow.
Trying to maintain the wrist position while moving at the elbow and pronating and supinating the forearm constantly changes the stress on these muscles.
Can you now start to understand why they get overused, are subject to microtrauma and degeneration, and get painful?

In addition to these stresses, raquet sports add further loads to these muscles.
Just imagine the extra load being applied by the impact of the ball on the raquet head in this picture!
The wrist extensors attached to the lateral epicondyle are having to stop the wrist from ‘breaking’ and keeping it firm to control the ball’s flight.
If you remember any of your school physics then you will recall that

EFFORT = LOAD X DISTANCE. 

Now think about the speed of the ball (loosely the Load = mass x acceleration) and look how far the ball is away from the wrist and start to calculate the increase in the ‘breaking’ force at the wrist!!

Be careful not to hit wet tennis balls – they weigh more and increase the load significantly!
Also your racquet needs to be strung appropriately for you. Increased tension in the strings increases the ‘forces’ generated in the racquet. These forces need to be controlled by the wrist and forearm.
It is essential that the grip of your racquet is appropriate to the size of your hand.
If you have any problems I would strongly advise seeking the advice of a professional tennis coach.

That is why you get Tennis Elbow with tennis backhands and also gripping activities, AND why avoiding gripping tightly will help your elbow to get better quicker!!

To summarise, you now should have an understanding of

• the anatomy of the elbow region
• movements at the elbow and forearm joints
• what Tennis Elbow is
• why gripping and raquet sports cause Tennis Elbow