A world-class runner almost always requires world-class DNA. You may not have the genes to be world class, but you can still be a better runner than you are now. Here are tips that can help make that improvement happen.

The first part is the most important: running with proper form. Don’t neglect the importance of proper arm movement and position. In fact, work on that first. Hold the arms with elbows bent at a 90 degree angle. The arms should swing forward and back as a counterbalance to each step. When the right foot steps forward, the left elbow should swing forward. But the arm movement should come from the shoulders, not the elbow.

The easing of tension in your shoulders should be the next point of improvement. Never “hunch” or stiffen your shoulders while running. They should stay relaxed to allow an effortless arm swing. Also pay attention to the way you hold your head. Your head should be upright, looking at the horizon. It should never be bent down to look at the road or at your feet. Nor should your head be even slightly tilted to one side or the other. Have someone video you while you are running so you can check for yourself the position of your head.

You may have noticed running magazines and books about running usually just advise using different kinds of running to train — sprints, intervals or long runs to build endurance. But this kind of training doesn’t necessarily build the sport-specific muscles or movement patterns needed to compete and stay injury free. In addition, many runners think aerobic exercise is all they need. They are wrong.

So the next part of improving is to hit the gym. Four prime exercises will build specific muscles to make you a better runner. The most important two are the squat and the dead lift. Each will strengthen the lower back, glutes and hamstrings. Your goal is to make these muscles stronger, but not to build bulk. The secret to accomplishing that is to lift lighter weights with many repetitions. For example, choose a weight which you can lift 20 times without exhausting your muscle power. Do one set, then rest for three to five minutes before doing the next set.

After you complete the lower-body exercise sets, it’s time for two upper-body exercises: the shoulder shrug and the lat pull-down. The shrug is simply holding a dumbbell or weight plate in each hand and lifting the shoulders. It will help your arm swing. The lat pull-down will help stabilize your spine, which is always good for a runner.

Before starting a resistance session, always do a warmup. A good warmup can be done on a treadmill. Swing your arms. Spend several minutes lifting your legs with each step to warm up your hips. Vary your steps — take long strides and short ones. The object is to flex and extend your joints to make the white tissues of the ligaments and tendons become stretched and pliable.

One essential fact: Do exercises that mimic the movement pattern of running. Purchase about 10 feet of rubber tubing with a medium strength. Tie this into a loop that can be placed around each ankle or calf, allowing one leg to extend, then the other, in a slow motion running pattern. Keep your knees flexed and your spine straight. You will strengthen your entire lower body without building any bulk at all.