When you crave variety, the gym is a great place to mix up your workout routine. You can go to the gym rain or shine. You can build up your strength and flexibility. And, you can have fun.

Anthony Martinez, training director at L.A. Fitness in Brookhaven, works with many runners and walkers training for an outdoor event like a 5K. Such clients tend to head for the cardio machines, but Martinez encourages them to strengthen their muscles as well when they come to the gym.

“Runners like to feel light, and a lot of times they don’t want to bulk up,” says Martinez, a certified personal trainer. “I tell them that building strength in the right muscle groups will help them with their running.”

He leads his clients through exercises for the hamstrings, inner thighs, calves and quads. Runners often want a challenging workout that delivers the euphoric feeling known as runner’s high. That is possible with strength-training, Martinez says. For example, you can alternate bursts of cardio and weight work.

For Martinez, a typical gym workout involves 30 to 45 minutes of cardio and 30 to 45 minutes of strength-training. He recommends varying your workouts and trying to make it to the gym three to four times a week.

“Clients stick with their fitness routine longer when they see results,” he says. “They let the gym become part of their lifestyle.”

Here are more of Martinez’s tips for runners and walkers wanting to make the most of their gym visits.

Get in the right frame of mind: The most successful clients arrive at the gym open-minded, ready to have fun and focused on their goals, Martinez says. Don't be defensive, and don't expect a shortcut.

Don't rely solely on cardio machines: Runners and walkers naturally gravitate toward the treadmill, but the gym has much more to offer. It's easy to be intimidated by the machines. Ask a trainer to show you how to use them properly.

Try plyometric training: A trainer can help you add these intense movements, which require strength and endurance. Runners like plyometric training, which involves stretching and contracting muscles, for the euphoric feeling afterward.

Build endurance with interval training: Like plyometric training, intervals provide an intense workout. You push as hard as you can for a short period of time and then slow down for a recovery period before starting another intense burst of cardio. Interval training can make a treadmill workout more productive.

Take a class: Martinez loves the way fitness classes motivate his clients. Classes offer a chance to try new things like Zumba and hip-hop dancing. Yet if you only go to classes when you go to the gym, you miss other things the gym has to offer.

Vary your weight-lifting routine: Trainers have long debated heavier weights and fewer reps vs. lighter weights and more reps. Martinez encourages his clients to do both.

Play it safe: Ask a trainer to help you master the proper form and tempo for each exercise. "If you use too much speed when strength-training, you can hyperextend or pull a muscle," Martinez says. "Injuries happen when the person goes overboard."

Hitting the gym can help you push yourself and become a well-rounded athlete. “If you stick to one thing, you limit your progress,” Martinez says. “Mixing it up is what leads to permanent change.”

About this series: Training for Your First 5K appears Wednesdays and features expert advice for all aspects of preparing for a 5K. Created by the Kaiser Permanente Run/Walk & Fitness Program, the goals are to inspire metro Atlantans to get fit and to promote workplace wellness.