AMT® HIIT Workout : The 15/15 Challenge


AMT® HIIT Workout : The 15/15 Challenge

This HIIT workout format is shown to produce significant increases in VO2 max³.  


What is HIIT? 

According to ACSM’s annual survey, High Intensity Interval Training (HIIT) is the number 1 trend in the fitness industry in 2014, thanks to its proven effectiveness for improving health, fitness and performance¹. HIIT workouts typically include short bursts (6 seconds to 4 minutes) of intense exercise alternating with relief breaks of varying lengths². Some HIIT benefits include an increase in VO2 max, an increase in stroke volume, body fat reduction, increased insulin sensitivity and more.

Why use the AMT for HIIT?

The AMT is unique in that it allows on the fly movement transitions in a non-impact, joint friendly environment. This is viable alternative for those looking to avoid plyometric or higher impact activities, or for clients that prefer to train in the cardio area.

Tips for Success

When performing HIIT on the AMT, structure workouts so that rest and work interval sequences rely on similar movement patterns to facilitate rapid transitions. 

Background and Structure of the AMT HIIT Workout: The 15/15 Challenge

This workout is based on a HIIT format identified in a 2007 study from the Norwegian University of Science and Technology that is shown to produce significant increases in VO2 max³.  In our workout, following a warm-up period, the exerciser performs a 24-minute workout comprised of 48 30-second sets made up of 15 seconds of work at 90-95% effort followed by a15-second recovery period. We recommend that the exerciser remains engaged throughout this workout by turning off the TV to maximize training efforts.

The AMT HIIT Twist

To keep exercisers engaged, the interval activity switches every 8 sets (4 minutes). Varying body position allows muscle groups more recovery time and increases training enjoyment. We recommend that trainers use the 10 minute warm-up period to introduce clients to the various body positions prior to the start of the HIIT segments.

What if this is too intense for my clients?

This workout can be modified base on an individual’s unique training capabilities. Trainers should always consider an individual’s readiness for exercise, physical and emotional stressors on any given training day, and training preferences before implementing this type of programming. Modifying body position, lowering resistance and reducing steps per minute during the intervals are great starting points for reducing the intensity of this workout. Trainers can also gradually introduce one or two segments into their clients’ training programmes, rather than coaching them through the entire 24 minute workout. Even 4 minutes of HIIT has been shown to produce significant physiological benefits. Finally, trainers can add in several minute recovery periods between each 4 minute segment.

Instructions for The 15/15 Challenge: An AMT HIIT Workout 

  • 40 minute workout 
  • 48 intervals of 30 seconds each 
  • Each interval includes 15 seconds work + 15 seconds recovery 
  • Every 4 minutes the interval activity changes
  • Increase intensity by varying speed; recover by reducing speed
  • Refer to table below for further instructions 



1. THOMPSON, WALTER R. Worldwide Survey of Fitness Trends for 2014. ACSM’s Health and Fitness Journal, Vol. 17, No. 6, pp. 10-20, 2014.

2. KRAVITZ, LEN. Metabolic Effects of HIIT. IDEA Fitness Journal, May 2014.

3. HELGERUD, J., K. HKYDAL, E. WANG, T. KARLSEN, P. BERG, M. BJERKAAS, T. SIMONSEN, C. HELGESEN, N. HJORTH, R. BACH, and J. HOFF. Aerobic High-Intensity Intervals Improve V˙ O2max More Than Moderate Training. Med. Sci. Sports Exerc., Vol. 39, No. 4, pp. 665–671, 2007.

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