ACSM'S Health & Fitness Journal:
DEPARTMENTS: Fitness Focus
Roy, Brad A. Ph.D., FACSM, FACHE
Brad A. Roy, Ph.D., FACSM, FACHE, is an administrator/executive director at Kalispell Regional Medical Center. He is responsible for The Summit Medical Fitness Center, a 114,800 sq ft medical fitness center located in Kalispell, Montana, and a number of other hospital departments.
Brought to you by the American College of Sports Medicine http://www.acsm.org
Most competitive athletes are acutely aware of the importance of including variable-intensity workouts into their comprehensive training regimen. Although continuous/constant effort workouts are important, discontinuous or interval training allows athletes to perform a greater volume of higher-intensity work that is not possible with prolonged continuous efforts. The good news is that interval training is not just for the elite athlete but also can benefit recreational athletes significantly, as well as people whose primary exercise focus is on improving their overall health.
INTERVAL TRAINING DEFINED
Interval training involves performing multiple repetitive exercise or work bouts that are broken up by active or passive recovery periods. By alternating repetitions of higher intensity with easier recovery periods, a tremendous amount of higher-intensity work can be undertaken — well beyond what could be accomplished in a continuous workout. Exercise intervals and recovery periods can range from a few seconds to several minutes depending on the workout objective. For example, a short, more intense work interval generally requires greater anaerobic metabolism and the recruitment of muscle fibers that can shorten the fastest, while longer, moderately paced intervals typically invoke greater participation of the aerobic system.
Training can be progressed by modifying one or more of the following variables:
* Duration/distance of the exercise or work interval
* Intensity/pace of the work interval
* Duration and type (passive vs. active) of the recovery interval
* Number of work intervals (repetitions)
* Number of repetition cycles or sets within the workout
HOW TO DESIGN AN INTERVAL WORKOUT
Starting an interval training program is relatively simple, even for the novice exerciser, and can be applied to a variety of activities such as walking, running, cycling, swimming, rowing, and even weight training. When planning an interval training workout, each of the variables in the above list must be considered in relation to the objective of the training session. For example, if the goal is to improve aerobic power, the work interval generally is set at 60 seconds or longer. The recovery interval can be passive (no activity) or light activity. The work-to-recovery ratio generally is set at 1:0.5 (e.g., 2 minutes hard:1 minute easy) or 1:1 for longer-duration work intervals. For shorter-duration, higher-intensity work bouts, a ratio of 1:2 or 1:3 can be used. As a general rule, the heart rate should drop into the 100 to 110 BPM range by the end of the rest interval. However, both the work and recovery heart rates can vary depending on a person’s age, health/fitness, and any medications they may be taking. Following are three examples of an interval session:
Walk/Jog: Warm up by walking for 15 minutes; jog for 30 seconds at a moderate to hard effort; walk for 90 seconds; repeat this cycle 10 times; cool down by walking for 10 minutes.
No caption available...Image Tools
Stationary Bike: Warm up with light peddling for 10 to 15 minutes; go hard for 1 minute, easy for 1 minute, hard for 30 seconds, easy for 90 seconds; repeat this cycle for 6 to 10 repetitions; cool down with light peddling for 10 minutes.
Elliptical Trainer: Warm up with light activity for 10 to 15 minutes; go hard for 2 minutes, easy for 1 minute; repeat this cycle 10 times; cool down with light activity for 10 minutes. After 2 weeks, consider increasing the work interval to 2.5 minutes.
BENEFITS OF INTERVAL TRAINING
Interval training is an excellent approach for nonathletes interested in general fitness and for athletes of any sport. Interval training works both the aerobic and anaerobic systems and leads to many physiological adaptations that improve speed, endurance, and performance. It also can result in increased caloric consumption and, perhaps best of all, interval workouts are fun and tend to go by more quickly than continuous training. If you are new to interval training or have a specific fitness goal in mind, you might consider meeting with a personal trainer who can help you set up a personalized workout.
© 2014 American College of Sports Medicine.