Planking is a strength training exercise; one of the key benefits is to improve your strength in various areas.
Lets take a closer look at the actual exercise. If you look closely at the front plank, you will notice the muscle groups being challenged.
If we start at the front, the first muscle being worked is your neck. In order to hold this plank position correctly you must keep your neck straight and not bending down. By keeping it straight you are working major muscle groups in your neck called the traps, this helps your posture especially if you spend a lot of time sitting at desk as it helps support your neck.
Moving along the neck, the next muscle group you will notice being used are your shoulders. Unless you go to the gym, shoulder muscles are generally not directly trained unless you do press ups for example. But who wants to do boring last century press ups? However, If you are a fan of press ups, which many are, performing the plank will also strengthen your shoulder muscles over time and thus improving the performance of your press ups as it uses similar muscle groups.
Holding the shoulders up are the biceps. If you are not into body building and building your biceps, merely performing the plank will help build and tonne your biceps as you are using your biceps to keep your upper body weight off the ground.
Right so that covers your upper body workout. Now if we travel along under the body, the next muscle group we hit is your chest, although I would say this is a secondary muscle group that is worked.
If we continue along we then come to the major muscle group being worked, the abs. Strong abs are vital not only for sport but also for good posture. This exercise will also strengthen your abs and as a result tonne them giving them a much more streamline look.
The muscle groups to the opposite side of the abs are your lower back muscles. These too play a vital role in keeping you in the plank position but also provide other key health benefits which i describe further down.
Moving along, the next muscle group we come to are the ones located in your bottom, yes these too are strengthen! From there you have the thighs and finally the calf muscles.