The Power of Intervals

Marathon runners do more continuous training, sprinters do intervals.
Which is the body you're looking for?

Interval training is where you do an activity at a higher intensity interspersed with periods of rest and/or low intensity activity.  Intervals have long been used in sports, but they should not be just reserved for athletes as some may think.  Some people, even some sport coaches, may think that intervals can't improve aerobic fitness or produce as much fat loss as longer continuous aerobic training.  I thought I'd just share a few studies with you that I came across in readings from strength coaches Mike Boyle and Robert dos Remedios.  At the end of the post I also give you some ways to implement intervals into your workouts starting today!

First, a study at East Tennessee State in 2001 compared two groups of obese women during an 8 week study.  One group did steady-state aerobic work and the other did high-intensity interval work.  They would workout until they burned 300 calories and then stop.  Each group exercised the same amount of days and weeks, but only the interval group loss fat.  Also, the interval group's metabolic rate was raised for 24 hours after working out, whereas the aerobic group had no change.

Second, a study at McMaster University in Canada also compared a steady-state group to an interval group.  The steady-state group performed 90 to 120 minutes of continuous cycling, and the interval group did four to six 30 second all out sprints with 4 minutes rest in between, which meant they only actually "exercised for 2 to 3 minutes per session out of a total time of around 20 minutes.  The study found no differences when they performed their final fitness tests, but amazing part was that the steady-state group committed 10.5 hours to training and the interval group only committed 2.5 hours to training (and less than 30 minutes of that was actually exercising).  So the same results came with far less time with interval training.

Lastly, a study at Tremblay in 1994 compared a group that did 20 weeks of steady-state training, and to another that did interval training for 15 weeks.  The steady-state group did burn more than 2 times the amount of calories (28,661 to 13,614), but the interval group burned more than 900% more subcutaneous fat (the fat right underneath your skin)!

There has also been more than a few studies that have shown interval training to actually improve aerobic capacity more than steady-state exercise.    The reason for this, and for the better fat loss results, may lie in a theory called Excess of Post-Exercise Oxygen Consumption (EPOC).  This basically means that your body continues to work and burn calories for up to 48 hours after a hard interval workout.  I am actually currently working on writing up a report on a large study I conducted last year that compared 2 types of interval training to continuous training that had some pretty significant results, but I'll save those for another post when my report is complete.  

Try putting interval training into your workout tomorrow.  This doesn't mean you have to do very intense training at first, start out slower and build up to more intense intervals.  Whether you are a weekend warrior, someone who needs to lose weight, or an athlete whose workouts don't currently include interval training, you can benefit from adding interval training.  Below are some examples of some different ways to perform intervals.  If you have any questions, feel free to contact me.  Start out with few reps and longer rest periods and work your way up.  Better results in less time, why not try them?

Although the following refer to running, you can use this for any mode of interval training (bike, rollerblading, swimming, jump roping, etc.).  There is far more options available for intervals than this includes, but this should give you a good idea of some that you can add to your training immediately.

The below descriptions cover more the use of conventional modes of "cardio" exercise, but intervals can also be done with bodyweight and lifting exercises, which will be covered in a future post.

Before all workouts do a short body weight circuit and/or run easy for around 5 minutes for a warm up.  You could also perform some light stretching.  Do static stretching after the completion of your workout.

1.Sprint Workout- Sprint as fast as possible until you feel like you are slowing down.  This usually will be around 5-8 seconds.  Let yourself slow down naturally and then walk until breathing is normal (can take up to or more than 1 minute).  Do 1-3 sets or 6-10 reps (max of 24 total reps).  Take as long as you need between sets.

2.One Word Pace Workout- Run for 20-30 seconds at a pace fast enough to where you can only manage to speak one word at a time, which is close to sprinting speed.  Then walk for 1-3 minutes.  Perform 1-3 sets of 3-6 reps (max of 15 total reps).  Take as long as you need between sets.

3.Couple Word Pace Workout-  Run for 1-2 minutes at a pace fast enough to where you can manage to get out a couple words at a time.  Then walk for 2-3 minutes.  Perform 1-3 sets of 2-5 reps (max of 10 total reps).  Take as long as you need between sets.

4.Sentence Pace Workout-  Run for 3-5 minutes at a pace where you are able to get only a sentence out at a time.  Then walk 3-5 minutes.  Repeat for a total of 4-8 times.

5.Fartlek Workout-  This run gives you a lot of variety and can be made as easy or as hard as you feel like you want it to be.  Always maintain at least a jog, and then at random times, perform one of the type of runs above.  Mix it up for the most variety.  Perform the run anywhere from 10 to 30 minutes depending on the time you have and how difficult you make it.

6.Conversation Pace Workout-  Although this doesn't qualify as interval training, it's still ok to add in a continuous long slow distance run now and then if you like that type of work.  Run at a pace where you could hold a conversation with someone for 20 to 40 minutes. 

As far as what workout you should do what day, just don’t do consecutive numbers back to back, i.e. don’t do workout 2 today and 3 or 1 tomorrow. These can be done on the same days as resistance training or on days in between.  If you do them on the same day as lifting, I would choose a more high intensity type workout and keep the sets and reps lower so that you complete the workout in a reasonable amount of time.