As athletes, we are constantly striving to push our bodies and minds in order to obtain a specific goal or title. In today’s society, it is easy to get caught up in the hottest fad in health and fitness, but the question always stands: will your training lead to your goal?

Several physiological factors must come together in order to elicit the most advantageous athletic performance. Finding optimization of these factors through an appropriate training protocol is the ultimate challenge for both coaches and athletes.1

Sure, everyone wants to get his or her heart rate up and work up a good sweat to feel accomplished at the end of a workout. Although, is this what a marathon runner needs? How about a triathlete? CrossFitter?

A study by Petré et. al. compared low-volume, high-intensity interval training (HIIT), with high-volume, medium-intensity continuous endurance training in highly trained individuals.2 HIIT is an exercise regimen similar to a standard CrossFit metcon. This training protocol involves several repetitions of exercise in quick succession, often transitions to medium-intensity, and ends with a cool down or rest period before beginning again. HIIT is often used by speed athletes such as sprinters and swimmers who are looking to gain stamina, without losing quickness or precision.1

But can endurance athletes benefit as well?

The goal of this study was to determine the effect on several cardiovascular and body composition related parameters. Results showed that aerobic power, or VO2max both relative and absolute only improved in the group receiving a combination of resistance training and HIIT training.2 Body mass and lean body mass increased slightly in the HIIT group, while only lean body mass increased in the continuous endurance training group.2 Time to exhaustion during the VO2max test increased in both groups, while maximal lactate steady-state workload also increased in both groups.2 Blood lactate levels after the VO2max test remained unchanged in the continuous endurance group, but increased in the HIIT group.2

These results show similar outcomes for both training protocols as far as endurance-related variables and body composition, while HIIT is less time consuming and can also affect aerobic capacity in a positive trend.

Another study by Stöggl and Sperlich explored the impact on endurance variables using polarized, threshold, high intensity, and high volume training groups.3 The polarized training group included HIIT sessions, long duration low intensity sessions, and moderate duration low intensity sessions. This group yielded the best results across all key variables of endurance performance in well-trained endurance athletes, including increased VO2peak, time to exhaustion, and peak velocity/power.3 Body mass was also assessed and was decreased with the HIIT training protocol, with no changes in the other groups.3

Overwhelmingly, the research favors variety.

Too much of one training stimulus can be detrimental to the body and it’s potential gains. It is important to understand that just because you are a marathon runner, it doesn’t mean you should only train steady state cardio. Just because you are a CrossFitter, doesn’t mean you should train at 90-100% intensity 24/7/365.

Do your research and question everything about your training. Training smarter is training with research-based intent, be the change.


  1. Horowitz D. High-intensity interval training (HIIT). Salem Press Encyclopedia. 2018. Accessed February 1, 2019.
  2. Petré H, Löfving P, Psilander N. The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals. Journal of Sports Science & Medicine. 2018;17(2):167-173. Accessed February 1, 2019.
  3. Stöggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Frontiers in Physiology. 2014;5(33):1-9. doi:10.3389/fphys.2014.00033. Accessed February 4, 2019.