The Loop

Fitness Friday: Everything you need to know about interval training

June 07, 2013

Editor's note: This week we welcome golf-fitness expert Ben Shear to the Golf Digest family. Ben (pictured), who has been a regular contributor to the magazine for several years, recently accepted our invitation to be added to our staff as a Golf Digest Professional Advisor, meaning he'll write golf-fitness articles exclusively for us. If there were a World Golf Fitness Ranking for trainers, Ben would be at the top of list. He is Director of Performance Training at his namesake facility, Ben Shear Golf, in Scotch Plains, NJ and Golf & Body NYC. He trains several players on the PGA Tour, most notably Luke Donald, Jason Day, Webb Simpson and Bo Van Pelt. To give you a taste of Ben's innovative, well-informed knowledge on fitness and biomechanics, I recently asked him for his take on a very popular fitness topic: interval training. Here are his thoughts.

--Ron Kaspriske, Golf Digest Fitness Editor

__Q: What is interval training?

A:__ It's an ambiguous term for any exercise that's performed vigorously for a period of time, followed by a rest or low-intensity cycle, and then another period of intense activity. These alternating cycles are typically 30-60 seconds in duration and the type of activity is usually running, cycling, rowing, etc.

__Q: What is the true benefit?

A:__ It's a very accurate measure of how hard you can work out. You push yourself to the limit and rest for only the amount of time it takes to be able to do the activity again. It's very efficient in that regard.

__Q: How about health benefits?

A:__One theory behind interval training is that it helps keep your body on "alert status." It prepares you for burst sports such as golf that require an intense amount of activity in a short amount of time. Another theory is that, as opposed to performing an athletic activity at a steady pace, intervals prevent your body from reducing the benefit of the exercise by quickly adapting to the challenge. Another theory is that it raises your resting metabolism and allows you to burn calories and lose weight more efficiently. 'Theory' is the key word here, because fitness experts are still examining the health benefits of interval training. One thing is for sure--you can get a good workout doing intervals in a shorter amount of time than if you were to, say, just run on a treadmill at a steady pace.

__Q: Any negatives to intervals?

A:__Whenever I hear about people doing them in groups, I just scratch my head. It doesn't make sense if everyone is doing something all out and then resting in the same prescribed amounts of time. One person could be doing these intervals with ease and the next person could be gasping for air with every rep. It's tough to get everyone working as hard as they possibly can, and that's the point of intervals. Another downside is that intervals require a heart-rate monitor. Not necessarily to know when to stop doing whatever you're doing--your body will tell you that--but to know when to start doing it again; when you've rested just enough to do another rep. You need a heart-rate monitor to keep the rest periods from being arbitrary.

__Q: If you were running an interval-training class, how would you make sure everyone worked out hard enough?

A:__ Simple. Instead of setting the reps by time, I'd have them set the duration of reps by their heart rates. No matter who is working out, the person would go all-out for 30 seconds once his or her heart rate rose above 80 percent of its maximum beats per minute. Then I'd have that person rest until the heart rate dropped back down to 65 percent. Then that person would ramp it up again. The duration for each rep simply depends on that person's heartbeat and its capabilities to speed up and slow down.

__Q: The 80-65 heart-rate interval makes great sense. Do you use a specific formula to determine a person's heart rate?

A:__ I like the Karvonen formula instead of the more common age-predicted table you see in a lot of gyms. The difference is that the Karvonen formula takes the varying fitness levels of individuals who are the same age into consideration. It does that by factoring each person's resting heart rate, which is a baseline indicator of physical fitness. The lower it is, the more efficient your heart is, because it's pushing a higher volume of blood with each beat. The formula goes like this: Subtract your age from 220. Then subtract your resting heart rate (beats per minute) from that number. Then multiply that new number by .65 (lowest point of your cardio-training zone) and by .80 (highest point). Finally add the resting-heart-rate number back into the formula to determine the range you want to work with in terms of intervals.


Here's an example: A 50-year-old man subtracts his age by 220 and gets 170. His resting heart rate is 66 so he subtracts that from 170 to get 104. He then multiplies that number by .65 (when rounded up, that number is 68). He then adds his resting heart rate back into the equation so it's 66 added to 68. That equals 134 beats per minute. That's the low end of his cardio-training range. The high end is determined by multiplying .80 to 104. That number, 83, is then added to 66 and the result is 149. So in this example, the 50-year-man would run, swing, cycle, row, etc., as hard as he could for 30 seconds once his heart rate passed 149. He would then rest for however long it took to get his heart rate back down to 134. He then would begin his next high-intensity rep.

The formula looks like this: 220 minus your age; minus your resting heart rate; multiplied by .65 and .80. Then add your resting heart rate to each number.

Look for more from Ben Shear in Golf Digest and also on Fitness Friday.

(Photo by iStockphoto)