By Jay Cardiello
October 09, 2013
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As a SHAPE reader, you've likely noticed how some workouts give a specific number of reps to do for each exercise while other routines say to do an exercise for a set amount of time. This also applies to runners-you're either counting miles or minutes. Each strategy is a good one, but one may be better for you. Use this guide to help determine which you should be doing.

Strength Training by Time

When a workout prescribes to do as many reps as possible in a set amount of time, concentrate on your form to ensure each rep is performed correctly so that, in turn, you get the most from your workout. Using a stopwatch can also boost your confidence since you don't have to worry that you won't be able to perform the recommended repetitions. Even if you can only complete one rep in the allotted time, that's a starting point. This strategy is particularly good if you work out with a partner. Often one person can feel inadequate or that she or he is holding back the other if they struggle to do 8 jump squats while their workout mate breezes through them. Forgetting the reps allows you both to push yourselves at your own levels and still get the benefits of a gym buddy.

Strength Training by Repetitions

Most sports training is repetition-based, which allows athletes-and everyday men and women-to peak, maintain a peak performance, and then de-condition as you increase or decrease the reps and weight used for each move. This also helps avoid burnout and overtraining because you're more in-tune to working from where you left off and keeping yourself at a pace that's working toward an overall goal. Lastly, having a tangible goal for each exercise, such as 10 pushups, lets you to see where you stand and gives you a feeling of accomplishment.

Cardio by Time

Most of us don't have a lot of time to work out, so training for time may be the best solution when you're trying to fit fitness into your day. Plus you don't have to try to calculate distance when running outdoors-using your watch as your guide is a no-brainer.

Cardio by Distance

Whether it is biking to the last telephone poll on your block or kicking it the last half-mile of your run, if you focus on time-based runs or cardio workouts, you may not push yourself to your maximum potential. In my experience, individuals are more willing to challenge themselves to, say, complete 3 miles as fast as they can, whereas they'll take a 30-minute run at a leisurely pace. Plus when you know the finish line is nearing, you tend to get tunnel vision and forget how tired you may be.

The Bottom Line

Each method can help you lose weight, build strength, become faster, and meet just about any fitness goal. I recommend mixing it up and personally do so depending on how much time I have: If I'm squeezing it in, I focus on time. If I have a free afternoon, I'll count my reps. Just remember to stay consistent, keep good form, and change it up so as not to reach a plateau. And have fun. Thinking too much about how you are going to work out may make you feel like it's a job-and fitness should be fun.