Tennis elbow, or Lateral epicondylitis, is a painful condition where the tendons in the elbow become weaker and weaker, degenerating the connection between the tendon and the bone. Pain is experienced on the outside of the elbow after the activity. If the muscles in the arm are overused in a specific way, such as being twisted the wrong way, or severely overworked, then pain becomes a problem and Tennis elbow is introduced. Age could also contribute to this condition. The symptoms of tennis elbow usually come and go within a 24 hour period, but as the condition worsens, the pain stays for a longer period of time. There are many different procedures that one can perform to hopefully better their condition, even as extreme as surgery, but healing usually simply takes time.
Tennis elbow, scientifically referred to as Lateral epicondylitis, is a painful condition in which the tendons in the elbow become weaker than they should be, weakening the foundation of the tendons where they attach to the bone. The outside of the elbow is the afflicted area, as that is where the muscle attaches to the tendon. The muscle involved here is the extensor carpi radialis brevis, which extends and stabilizes the wrist. However, once the tendons are weakened because of this condition, the muscle becomes harder to use, and the person suffering from the condition begins to suffer from pain when performing simple activities, such as gripping, lifting, or grasping certain objects. Sports are the main offender when talking about tennis elbow, but other activities can also cause it. . The condition was first mentioned in 1883 in a paper called Lawn-Tennis elbow, but the condition was first mentioned in 1873. 
There are a few causes to tennis elbow. The extensor carpi radialis brevis (ECRB for short) works to stabilize the wrist while the forearm is straight and extended. If this muscle is overused, in tennis for example, it becomes weaker through microscopic tears. Eventually this will lead to pain and inflammation. Most injuries occur from the wrist being overly twisted in different directions. Activities that are stressful to the arms also could cause tennis elbow. Painting, plumbing, and carpentry can often cause tennis elbow. Age is also a factor, as 30 to 50 year olds develop tennis elbow more than the rest of the population. There are unknown factors that also contribute to tennis elbow.  Another cause could be direct trauma to the elbow, such as impactful blows, forcefull pulls, or exertion. Other disorders that weaken the body could also cause tennis elbow, like carpal tunnel syndrome, bicipital tendinitis, or rotator cuff injuries. One researcher states that the radial nerve plays a crucial role in its contractions with certain muscles and joints. 
One will experience the symptoms of Tennis Elbow within 24 hours of their activity. Soreness often occurs after one exercises the muscles in their forearm. This dull and aching pain should leave within 24 hours in the early stages of Tennis Elbow, but as the condition gradually increases, it will also take longer for the pain in the elbow to leave as well. This pain could eventually spread to other parts of the upper body, such as the neck, shoulders, and so on. For the most part, this pain will effect the dominant arm. The pain exists on the outside of the elbow, away from the person. This pain could possibly cause sleeping problems, as the pain keeps people awake at night. The pain will begin as a dull ache, but soon, any physical activity at all, such as carrying bags, picking up jugs, or things like that, will cause one to ache.  There will often be tenderness in the elbow after strenuous activities that one participates in, such as tennis. There are not any other symptoms of Tennis elbow that are life-threatening to someone suffering from this injury.
A simple video to see if you have Tennis elbow.
- Tennis Elbow - Lateral Epicondylitis "ASSH" 5 May, 2015 (Date-of-Access)
- Tennis Elbow "Wikipedia". 5 May, 2015 (Date-of-Access).
- Tennis Elbow (Lateral Epicondylitis) "OrthoInfo". 5 May 2015 (Date-of-Access).
- Tennis Elbow "Wikipedia" 5 May, 2015 (Date-of-Access).
- SYMPTOMS "WebMD" 18 May, 2015 (Date-of-Access).
- Tennis Elbow "WebMD" 18 May 2015 (Date-of Access).