You're a committed fitness fanatic looking to optimize your results. Or perhaps you've just begun your journey to improved health and want to establish a rounded fitness training routine. Regardless of your present level of physical fitness, it's important to base your exercise goals upon these four primary elements of fitness.

Any activity you do — from taking a walk to washing the dishes — requires oxygen. Regular aerobic fitness exercise increases your body's ability to use oxygen. How well you use oxygen is termed your "aerobic capacity." When your aerobic capacity is high, your heart, lungs and blood vessels efficiently transport and deliver large amounts of oxygen throughout your body.

Aerobic exercise helps you in your daily activities. It helps your heart, blood vessels, lungs and muscles complete routine tasks and rise to unexpected challenges, such as running to your car in pouring rain.

The key to achieving aerobic capacity is to find fitness training activities that you enjoy and can do regularly. You needn't limit yourself to a single activity, such as running. Add variety and increase your motivation by trying different types of aerobic activity, such as dancing, bicycling or water aerobics. Aerobic exercise at least 10 minutes in length is required to obtain health benefits.

Muscular fitness refers to the strength and endurance of your muscles. The more fit your muscles are, the easier your daily tasks become, whether they include lifting groceries, raking the yard or pushing a vacuum cleaner.

Strength training can help you improve your muscular fitness. It also enables you to increase your body's lean muscle mass, which helps with weight loss.

Training options include using free weights, resistance bands, weight machines or your own body weight to increase muscular strength and endurance. Fitness training that includes more than one option will help ensure greater overall muscular fitness.

Flexibility is the ability to move your joints through their full range of motion. You maintain your body's flexibility through stretching. When you're flexible, routine tasks, such as lifting packages, bending to tie your shoe and hurrying to catch a bus, are easier and less tiring.

Fitness training activities that lengthen your muscles increase your flexibility. One way to become more flexible is to include stretching exercises in your fitness routine. Yoga and tai chi, if performed correctly, can be effective for improving flexibility. No matter what type of stretching exercises you choose, make flexibility training an integral part of your fitness plan.

Stability and balance are associated with your body's core muscle strength — the muscles in your lower back, pelvis, hips and abdomen. These core muscles provide the support system for almost any activity or motion your body makes. They help you maintain stability and balance during your daily activities.

You can improve your stability and balance through core exercises that strengthen the muscles at the center of your body — the area around your trunk — where your center of gravity is located. A strong midsection helps combat poor posture and low back pain. It also helps prevent falls, especially in older adults.

Whether you create your own fitness training plan or work with a personal trainer, make aerobic fitness, muscular fitness, flexibility, and core strengthening for stability and balance a part of your overall exercise plan. Factoring in these four fitness elements can help you live a longer, healthier life.