You’ve heard it over and over: “Don’t train harder, train smarter.” But sometimes “train smarter” means “train harder.” Like when you’re not reaching your goals even though you show up at the gym, or run or bike regularly. If you’re an experienced exerciser and you’re not hitting your personal bulls-eye, maybe you’re not working out hard enough.

Training harder isn’t for everyone. It’s not for beginners, sporadic exercisers, or for those coming back from injury. But if you’ve got your fitness habit down, yet your body is coasting, working out harder may take you to a new frontier. You’ll get increased health, fitness, calorie-burning, efficiency, and longevity benefits. Here’s how:
9 WAYS TO WORK OUT HARDER

1. Patrol your pulse. A heart rate monitor lets you know precisely when you are in your target zone, so you can push without guesswork. Aim for 75 to 85 percent of your heart-rate max on high-intensity days, restricting yourself to once or twice a week if you’re moderately fit, three to four times a week if you’re highly fit. Caution: Unless you’re a very serious athlete, avoid going over 85 percent for more than a few minutes – this can lead to injury, soreness, strained muscles and ligaments, and longer recovery time, warns Edmund R. Burke, Ph.D., sport scientist at the University of Colorado at Colorado Springs and author of Serious Cycling (Human Kinetics, $19) and other books.

2. Mix it up. The components you can vary in an aerobic workout are frequency, intensity, type, and time (the “FITT” principle). Regularly change one or more of these. If you’re used to three aerobic workouts a week, challenge yourself with four or five. Go harder. Go longer. Switch to something entirely different. If you’re training for a particular sport, you’ll get the most benefits by training as specifically as possible for that sport. But you still want to vary activities to avoid overuse injuries.

3. Go long and slow. Once or twice a week, add quality to your aerobic workout by going extra-long with your heart rate about 60 percent. This will increase your endurance, helping you train for longer races or events, and burn calories.

4. Get off track. Whether you’re cycling or running, you can accelerate your progress by abandoning your usual course and adding a variety of challenges and terrains. Pepper your endurance rides or runs with some that are shorter, but have killer hills, and work on speed and power. Or try something completely different that use the same muscles, like in-line skating or hiking up hills.

5. Do intervals. Instead of zoning out on the stair climber, stationary bike, treadmill or track, pep up your workout with intervals. Alternate different intensities and elevations so that your body has to work harder.

6. More is better. One of the mistakes we make in the gym is working small muscle groups in isolation, according to Daniel Kosich, Ph.D., president of EXERFIT lifestyle consulting in Denver. Power up your workouts by choosing exercises that include several muscle groups and that mimic the way you’ll use these muscles in real life. For example, choose a squat or lunge instead of seated knee extension.

7. Startle your muscles. Doing the same weight-training workout day after day, week after week, is the kiss of death. Muscles respond to variety, so change as much as you can — type of resistance equipment as well as specific exercises — from one workout to the next. By varying the way you work each muscle, you stimulate more muscle fibers, leading to greater strength and size.

8. Lift to fatigue. Overload your muscles with heavier resistance by continuing each exercise until you cannot perform another repetition in proper form. If your weights are heavy enough, your form is correct, and your movement is slow, you only need one set to reach fatigue. The key is to take momentum out of it, which makes the exercise harder. Perform 8 to 12 reps slowly, with weights heavy enough that the last rep is honestly the last one you can do without breaking form.

9. Take a rest. Part of working harder is resting harder. For every 4 to 6 weeks of hard training, take a “restoration week” with your training volume and duration at 50 percent of your high-intensity workout, suggests Marc Evans, former U.S. triathlon team coach and author of Endurance Athlete’s Edge (Human Kinetics, $20). “Swim when you want, bike when you want, run when you want,” says Evans. “And don’t be so narrowly focused that the whole day is shot if you don’t make your workout.” Backing off gives you the physiological break you need to adapt to your previous weeks’ workouts without overtraining and helps you stay fresh mentally. The body needs a mix of stress and rest to get fit and overcome a plateau.