What muscles are most important to workout?

​Some people come to their personal trainer and say:
“I want to focus just on my arms, as my arms are weak”
“I want better core”
“I would like stronger legs”
Should you only focus on one area when working out? For most people, you shouldn’t just focus on one area, as there is no one muscle more important than another.
Let’s take a brief look at the various body sections:

1. Heart
One of the critical muscles in the body is the heart!
The human heart is the most incredible muscle in the body, beating about 100,000 times to send 3,600 gallons of blood through 75,000 miles of blood vessels every day.
Exercise has numerous benefits, including improving heart health to reduce the risk of heart disease. Cardio work will help with efficiency and power of the heart.
Examples of aerobic exercise include running, rowing, cycling, swimming, walking, and hiking.
Strength training exercises like lifting weights will also boost heart  health.

Cardio training

2. Core
When we think of the core muscles most people think of their abdominal muscles. However, our core is made up of many more muscles including the diaphragm, pelvic floor, paraspinal muscles (the muscles that wrap around the spine), gluteal muscles (our butt muscles), and abdominals. 
A weak core can lead to balance issues. We often feel less steady on our feet and may have trouble getting out of our chair or car. This is because the core is the foundation of the body. We must engage all of these muscles to walk, stand, and exercise. If our core is not strong, then our legs and arms will not work as well, even if they are strong too. 
When we strengthen the core, we are working to keep the entire body stable. Our core gives us our sense of balance. It is also responsible for stabilizing both the hips and shoulders, as well as protecting the spine. This helps with everyday tasks like carrying groceries and stepping out of the shower. It also helps if you play sports – swinging a golf club or tennis racket is much easier with a strong core. 
We can improve our core strength by doing planks, leg lifts, superman stretches, and glute bridges. 

Core training

3. Leg Muscles
All of our leg muscles are important, but it is especially important to work big muscles like the hamstrings and quadriceps. These will provide the strength to stand up and walk easily. You can strengthen these muscles by doing squats, lunges, heel raises, step-ups, and hamstring curls. 
Keeping the smaller muscles in our legs in shape is also important. We can strengthen the smaller muscles near the ankles and knees by doing balance work. These smaller muscles also help us to stay mobile, so we can walk, run, dance, and swim with ease. Examples of balance exercises include standing on one leg, walking heel to toe.

Lower body training

4. Upper Body
The shoulders, upper back, and arms can help us stand up, grip rails and keep us balanced. A strong upper body is essential for good posture
The main muscles included Pectoralis major and minor (chest), Rotator cuffs, Deltoids (shoulders), Latissimus dorsi (middle back and sides), Trapezius (upper back), Biceps and Triceps
Upper-body strength is the ability to push, pull and press with the arms, shoulders, back and chest in multiple directions while having full control of the range of motion
For better balance and stability, focus on strengthening the upper back, shoulders, and triceps. You can do these with exercises such as standing rows and shoulder presses. Planks are also great for strengthening the upper body as well! 

Upper body training

Conclusion:
In general it is important to train your whole body. Some people may train upper body one day, and lower body next day. Others do a full body workout each time. Both approaches are fine, and it is often a personal preference, or depends if you are training for a specific event. The key thing is that you are training all your muscles over time! Increasing muscle mass on the body comes with benefits like boosted metabolism, stronger bones and a healthier heart.  Upper-body strength isn't more important than leg strength. But it is equally as important. Having an overall balance of strength, from head to toe, will help you achieve any fitness goal and improve your health.