In one sentence, describe what the following article is about:

Strains and sprains are two similar (but not identical) types of injuries with related symptoms that can affect the back. Strains involve pulled or torn muscles or tendons, while sprains involve pulled or torn ligaments. In either case, the injury will generally be accompanied by noticeable pain that gradually subsides over a week or two. To fake this convincingly, you'll want to pretend that part of your back (e.g., upper back, lower back, shoulder region, etc.) is painfully sore like a bad bruise.  For example, let's say that you're faking a strain in your upper back after picking up a heavy box with bad posture. In this case, you might want to do the following to give a convincing performance: Grunt or shout in pain as soon as the injury "happens." Have the "pain" gradually subside over an hour or so until you're simply "sore." After this, wince whenever anything touches your upper back (e.g., a friend pats you on the back, you brush against a coat rack, etc.) Go slowly and tenderly when you have to press your upper back into anything (e.g., you have to sit back into a chair, etc.) A real back strain or sprain can leave you with the feeling that you've just had a very intense workout, but in a bad way. As your body repairs your damaged ligament, tendon, or muscle, the area around it will remain sore to any sort of disturbance — even those caused by simply moving. Thus, if you're faking this sort of injury, you'll want to mimic pain and stiffness whenever you do anything that moves the part of your back you've injured.  For example, if you're dealing with a fake upper back sprain, when doing the following sorts of things, you'll want to put on a pained facial expression, wince, and act like you don't have our normal amount of flexibility: Throwing something Picking something up from the floor Pulling something apart (e.g., packaging, tough food, etc.) Putting on or taking off a coat Raising a hand Doing any sort of high-impact exercise (e.g., running, jumping, etc.) Especially bad sprains and strains can lead the muscles in the area of the injury to misfire, causing painful contractions called cramps or involuntary motions called spasms. These can be intensely painful and can be triggered by using the affected muscles, though they can also sometimes occur randomly. A cramp should "hurt" a lot more than the simple soreness that comes with a healing sprain or strain, so try to sell your sense of pain and surprise. It will also cause your muscles to bunch up and become tight, so you'll probably want to flex your back muscles hard until the cramp "goes away" (which usually just takes a minute or two.)  For example, acting out an upper back cramp might go like this: When people are around you, stoop to pick up something on the floor. Gasp and grab your lower back. Grimace in pain when people are looking. Slowly stretch back into a standing position and pretend like you are still in pain. Gradually decrease your "pained" performance throughout the rest of the day. Acting like you have a sprain or strain in your back will naturally attract curious questions, so have a good story ready. In general, most sprains and sprains in the back are caused by putting excessive stress on the muscles, tendons, and/or ligaments (either all at once or over time). Sprains and strains have slightly different causes, so be sure to know the difference to keep your story consistent. See below.   Strains are often caused by: Suddenly twisting or pulling the muscles in the back, especially when handling something heavy. Stressing the muscles by attempting to lift something too heavy. Fatiguing the back muscles too frequently, especially with improper form.  Sprains are often caused by: A sudden blow to the back. A fall. The back being forced to stretch beyond its natural flexibility A sharp, sudden bend or twist in the back. Enhance the illusion of your back sprain or strain by pretending to treat it. Most sprains and strains, though painful, can be treated with basic home remedies, so this should be fairly easy to fake! Real sprains and strains usually get better with the following remedies:  Ice packs Warm compresses/baths Small doses of over-the-counter painkillers and anti-inflammatories (Acetaminophen/Paracetamol, Ibuprofen, etc.) Gentle massage (for cramps) Slowly stretching against the pull of the muscle (for cramps) Rest (for especially bad sprains or strains); doctors recommend no longer than two days, as any longer typically makes healing take longer. It is up to you whether you want to follow this rule for your fake injury.

Summary:
Act like part of your back feels painful and sensitive. Act like the pain becomes more intense with movement. Optionally, fake cramps or spasms. Make a convincing story for your sprain or strain. Know how to "treat" your sprain or strain.