High Intensity Circuit Training Benefits

HICT FOR FAT/WEIGHT LOSS

HICT (High-Intensity Circuit Training) can be a fast and efficient way to lose excess body weight and body fat. The incorporated resistance training contributes significantly to the amount of fat burned during a workout. When resistance training exercises using multiple large muscles are used with very little rest between sets, they can elicit aerobic and metabolic benefits. Research has found that these metabolic benefits can be present for up to 72 hours after a high-intensity exercise bout has been completed.

There also may be a greater impact on subcutaneous fat loss with high-intensity intermittent circuit-style resistance training protocols than with traditional steady state sustained-effort aerobic work or traditional resistance training. This is thought to be from the increased level of catecholamines and growth hormone found in the blood both during and after a high-intensity resistance training exercise with shortened rest periods (<30 seconds).

Shorter rest periods result in shorter total exercise time. This is attractive to individuals who are trying to maximize the impact of an exercise program in minimal time.

HICT MAY IMPROVE MARKERS OF HEALTH

HICT may be an extremely effective and efficient means by which to increase an individual’s V˙O2max, a well-established marker of cardiopulmonary health. When HICT protocols have been compared with traditional steady state protocols in the laboratory, HICT elicits similar and sometimes greater gains in V˙O2max, despite significantly lower exercise volume.

HICT can be an efficient approach to decreasing insulin resistance as well — a major factor in developing type 2 diabetes. Positive changes have been observed in insulin resistance in as little as 8 minutes per week when executed at an intensity of more than 100% V˙O2max.

DESIGNING AN EFFECTIVE HICT PROGRAM

Contraindications

Because of the elevated demand for exercise intensity in HICT protocols, caution should be taken when prescribing this protocol to individuals who are overweight/obese, detrained, previously injured, or elderly or for individuals with comorbidities. For individuals with hypertension or heart disease, the isometric exercises (wall sit, plank, and side plank) are not recommended. The isometric exercises can be substituted with dynamic exercises. For all individuals, the Valsalva maneuver should be avoided, particularly for the isometric exercises. Proper execution requires a willing and able participant who can handle a great degree of discomfort for a relatively short duration. It is also essential that participants in a HICT understand proper exercise form and technique. As with all exercise programs, prior medical clearance from a physician is recommended.

Although HICT can be an efficient means by which to improve health and decrease body fat, it may be inferior to creating absolute strength and power, specific endurance, and other specific performance variables. If these are the goals of a program, as with competitive athletes, traditional programs may elicit greater absolute gains.

Exercise Selection

The exercises selected for a HICT circuit should function to:

1. promote strength development for all major muscle groups of the body

2. use large muscle groups to create the appropriate resistance and aerobic intensity

3. create a balance of strength throughout the body (e.g., you would not want to prescribe five exercises for one body part while only prescribing one for another; creating a balance of strength around a joint is an effective way to prevent injury and improve movement efficiency)

4. be immediately modified or adapted as necessary to increase or decrease exercise intensity

5. be safe and appropriate for the participants in the training space provided

6. be interactive with the available features of the training environment (e.g., stairs, benches, walls, etc.)

7. be easily transitioned to accommodate minimized rest time

Number Of Exercises 

The original circuit training protocols called for 9 to 12 exercise stations. There is no ideal number of exercise stations; however, it is important that, for a general program, all muscles are used at an appropriate intensity during a training session. The number of exercise stations also will affect the total exercise time.

Individual Exercise Bout Time

Generally, the longer the exercise duration, the lower the exercise intensity that can be accomplished. To maximize the metabolic impact of the exercise, time should be sufficient enough to allow for the proper execution of 15 to 20 repetitions (15) of an exercise.

A 30-second exercise bout is adequate to allow for this because most participants are able to acquire and maintain appropriate intensity for 30 seconds. Participants can assess absolute intensity by monitoring their heart rate either manually or with a heart rate monitor during exercise.

Rest Between Exercise Bouts

When rest intervals are too long during HICT, it undermines the purpose of the high-intensity protocol, which is to create maximal exercise intensity in minimal time. To maximize the benefits of this type of training, 30 seconds of rest or less has been observed to maximize metabolic impact (6). Overall, the objective is for incomplete recovery between exercises so the high exercise intensity can be sustained for the short duration circuit, without compromising proper exercise form and technique.

For maximum time efficiency, we recommend minimizing (≤15 seconds) rest time between body weight exercises in a HICT protocol to maintain appropriate exercise intensity.

Total Exercise Time

Research has demonstrated that improvements can be made in V˙O2max and insulin sensitivity in as little as 4 minutes of total exercise time in a HICT session. However, it is to be noted that this result often requires working at intensities equivalent to greater than 100% of V˙O2max.

More moderate protocols (90% to 100% of V˙O2max) have been examined for various total exercise durations. Although these protocols seem to require slightly more total exercise time to be effective, they still are well below the steady state exercise time requirements.

Because most individuals may not be able to execute the program at an intensity significantly greater than 100% of their V˙O2max, following the established ACSM guidelines for the high-intensity exercise of at least 20 minutes is recommended. This may require multiple repetitions (or circuits) of a multistation exercise circuit.

HICT SAMPLE PROGRAM

The following is an example of a 12-station HICT program. All exercises can be done with body weight and implement easily acquired in almost any setting (e.g., home, office, hotel room, etc.). The exercise order allows for a total body exercise to significantly increase the heart rate while the lower, upper, and core exercises function to maintain the increased heart rate while developing strength.

Exercises are performed for 30 seconds, with 10 seconds of transition time between bouts. Total time for the entire circuit workout is approximately 7 minutes. The circuit can be repeated 2 to 3 times.

1. Jumping jacks Total body
2. Wall sit Lower body
3. Push-up Upper body
4. Abdominal crunch Core
5. Step-up onto chair Total body
6. Squat Lower body
7. Triceps dip on chair Upper body
8. Plank Core
9. High knees/running in place Total body
10. Lunge Lower body
11. Push-up and rotation Upper body
12. Side plank Core

SUMMARY

HICT seems to be an efficient means of exercise to help decrease body fat, improve insulin sensitivity, and improve V˙O2max and muscular fitness. As the hectic pace of today’s corporate world continues to infringe on the amount of time individuals have for exercise, these types of programs can offer a good option to help busy individuals improve their health and recover from stress via exercise.

The practicality and accessibility of HICT using body weight as resistance makes this exercise program a viable option for the masses. Individuals who previously believed that they did not have the time for exercise can now trade total exercise time for total exercise effort and get similar or better health and fitness benefits.