The modern work lifestyle is harmful for most people, especially with the number of hours you are sedentary. The human body needs exercise, without which it develops several problems, like back pain.

If you have a body part that is in pain or feels underdeveloped, what do you do? The Internet has plenty of exhaustive resources on how to exercise, but it's difficult to find the right one for your needs.

It's about knowing where to look. From gym workouts to yoga, these sites and tools will give you the right exercise for any body part, whether it's to develop muscle or relieve pain.

Be warned, if you have chronic pain, you should see a doctor and check with them if the recommended exercises here are okay for you. But if it's early signs of pain and you want to relieve it, focused workouts are the way to start.

MuscleWiki (Web, iOS, Android): Gym Workouts for Specific Muscles

MuscleWiki is inspired by the r/fitness Reddit community. Hey, we told you Reddit can be productive! You'll need to hit the gym or build a home gym with the appropriate equipment for this one. Start the app, choose whether you're male or female, and select the body part you want to work on from the human body map.

It will start you off with a short description of that muscle along with what it does. MuscleWiki will then display the exercises you should be doing to develop that muscle, complete with detailed instructions as well as GIFs to illustrate the right technique.

The free apps include all these GIFs online, so they are pretty big downloads, taking over 200MB of space on your smartphone. But the good news is that you can then use them in the gym without worrying about the Wi-Fi or data connection.

Download: MuscleWiki for Android (Free) and for iOS (Free) [No Longer Available]

Yogapedia (Web): Yoga Poses by Body Anatomy

Yoga isn't the mystical exercise it's often made out to be. Anyone can do it, and it's quite effective if you are trying to relieve back pain or other specific aches. Yoga Journal's Yogapedia categorizes the different asanas, or poses, by which part of the anatomy they have an impact on.

Back, abs, knees, hips, hamstrings, neck—whatever you can think of, there is some asana for it. Yogapedia not only shortlists the asanas and gives you step-by-step instructions, but it also lists the cautions you should be aware of, tips for beginners, variations of the pose, as well as preparatory or follow-up poses.

In short, whether you're new to yoga or you've been practicing it for some time, you'll get something useful from Yogapedia.

Body Weight Training Arena (Web): Calisthenics for Any Body Part

Body-weight training is a growing trend to adopt exercises that don't require any special equipment or apparatus. It's not a new idea though. That's the premise of calisthenics, which is a series of gymnastic routines based on using your body's weight to train yourself.

A good example of calisthenics is push-ups or crunches—you don't need anything apart from your own body, and can do these exercises wherever you are. To find a calisthenics routine for the body part you are interested in developing, check out Body Weight Training Arena's short guides.

Pick the body part to get a chart of what you should do. Plus, it's printable, so you can just stick it up in the part of your house where you'll do these workouts regularly. The only problem here is that it's a limited set: full body, biceps, upper body, legs, shoulders, chest, and turtle back.

ExRx Directory (Web): Understand Individual Muscles and Exercise Them

ExRx has been around on the Internet for a long time, and is one of the most-recommended fitness resources you'll find. Particularly, its exercise and muscle directory has all the information you could need to understand the muscles in your body and the exercises you need to perform for them.

For example, if you don't know what the quadriceps are, click that in the "Muscle" list to find a diagram, an explanation of what they do, other names, and common ailments.

Switch to Quadriceps in the "Exercise" list to see a huge list of different workouts for your quads, broken down in categories like stretches, self-assisted, dumbbells, barbells, and so on. And yup, it will demonstrate the exercise with a GIF since that's the language of the Internet.

If details are what you want, ExRx is where you need to go.

ACE Library (Web): The Best Place to Learn Proper Form

The American Council of Exercise (ACE) also breaks down workouts by body part or by equipment, much like the above sites. But more importantly, it focuses on instructions for the proper form.

Improper form is the easiest way to end up injuring some body part while exercising, and more likely the same part that you were trying to improve. Your posture and your technique will dictate whether you are actually exerting the right muscles, so this is paramount to getting a fit body.

As you might have guessed, ACE is a non-profit organization that works with a variety of doctors, physiotherapists, and instructors to provide the best possible information to anyone. Whichever of the aforementioned sites you choose in the end, make sure you cross-check with the ACE Library for the proper form.

Aerobic vs. Anaerobic: Your Vote

There are two basic types of exercise. Aerobic exercises typically don't use special equipment and rely on natural modes like running, climbing, and so on. These benefit in increased stamina and better cardiac health. Anaerobic exercises implement external equipment like weights, and is more effective in building muscle mass.

Which of the two do you prefer and why? Tell us about any exercise resource you use to enhance your fitness.

Image Credit: Backache by goir via Shutterstock