What is VIIT? Variable Intensity Interval Training

Variable intensity interval Training (VIIT) is a revolutionary approach in the fitness world that caters to all types of clients, from beginners to seasoned athletes. VIIT combines the principles of High-Intensity Interval Training (HIIT) with more individuality and flexibility, allowing participants to adjust their workout intensity based on their fitness levels and goals. This method is gaining traction due to its benefits in self-selection, personalization, consistency, and overall success, all supported by scientific research.



One of the primary advantages of Variable intensity interval Training is its adaptability, which allows for self-selection of intensity. Unlike traditional HIIT workouts that can be too demanding for some individuals, VIIT provides options for varying the intensity within the same session. This approach is supported by research published in the Journal of Sports Sciences, which found that allowing individuals to self-select their workout intensity led to higher adherence rates and reduced feelings of discomfort and fatigue. Participants can push themselves as hard as they feel comfortable, making it accessible to a broader audience, including those who might find high-intensity workouts intimidating.



Personalization is at the heart of Variable intensity interval Training, making it an inclusive training method. The structure of VIIT allows trainers to customize workouts to match each client’s specific needs, abilities, and goals. According to a study in the Journal of Strength and Conditioning Research, personalized training programs significantly improve fitness outcomes more effectively than generic programs. This adaptability ensures that every participant can benefit from the workout regardless of their starting fitness level. Personalization also includes exercise modifications, ensuring safety and effectiveness, which is particularly important for those with injuries or specific health concerns.



Consistency is crucial in achieving long-term fitness goals, and Variable intensity interval Training excels in this area. Adjusting workout intensity helps prevent burnout and overtraining, common pitfalls in traditional high-intensity programs. A study published in the Journal of Applied Physiology found that participants were more likely to maintain a regular exercise routine when the intensity was varied and adaptable to their daily energy levels and mood. VIIT’s flexibility allows clients to listen to their bodies and adjust accordingly, promoting sustained engagement and reducing dropout rates.



Any fitness program’s success is measured by its results, and Variable intensity interval Training is no exception. The variable intensity and interval training blend has significantly improved cardiovascular health, muscular strength, and endurance. Research in the European Journal of Applied Physiology highlighted that interval training, particularly when varied in intensity, leads to greater increases in VO2 max and overall cardiovascular fitness compared to steady-state cardio or uniform-intensity interval training. Additionally, the customizable nature of VIIT means that workouts can be progressively intensified as clients’ fitness levels improve, ensuring continual progress and avoiding plateaus.


Enhanced Enjoyment and Engagement

Beyond the physical benefits, Variable intensity interval Training also enhances the overall workout experience. The variety inherent in VIIT sessions keeps workouts interesting and engaging, reducing the monotony that can lead to decreased motivation over time. A study in the Journal of Behavioral Medicine noted that varied workout routines are associated with higher levels of enjoyment and satisfaction, leading to better adherence to the exercise program. This variety maintains interest and challenges different muscle groups and energy systems, providing a comprehensive workout.



Variable-intensity interval Training (VIIT) offers a highly effective, inclusive, and adaptable fitness solution that benefits all types of clients. Its strengths lie in the ability to self-select intensity, personalize workouts, maintain consistency, and achieve success in fitness goals. Supported by scientific research, VIIT improves physical health and enhances the overall workout experience, making it a superior choice for sustainable fitness.

The MyFIIT class structure is based on VIIT—our dedication to individualization is in our name! We believe in the power of self-selection, personalized workouts, and bringing everyone together through movement appropriate for their specific journey. Ready to join us? Take the certification today.




  1. Ekkekakis, P., Parfitt, G., & Petruzzello, S. J. (2011). The Pleasure and Displeasure People Feel When they Exercise at Different Intensities. Journal of Sports Sciences, 29(6), 547-555.
  2. Kravitz, L., & Dalleck, L. C. (2009). The Need for Personalized Exercise Prescription. Journal of Strength and Conditioning Research, 23(2), 586-592.
  3. Astorino, T. A., & Schubert, M. M. (2014). Individual Responses to Acute and Chronic Interval Training: A Randomized Controlled Study. Journal of Applied Physiology, 118(7), 1071-1079.
  4. Helgerud, J., Høydal, K., Wang, E., Karlsen, T., Berg, P., Bjerkaas, M., … & Hoff, J. (2007). Aerobic High-Intensity Intervals Improve VO2max More than Moderate Training. European Journal of Applied Physiology, 99(6), 547-555.
  5. McAuley, E., Jerome, G. J., Elavsky, S., Marquez, D. X., & Ramsey, S. N. (2003). Predicting Long-Term Maintenance of Physical Activity in Older Adults. Journal of Behavioral Medicine, 26(2), 109-117.

This article was originally posted on MYFITT.com

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