1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
My name is Christoph Zinner and I studied sports science at the German Sports University Cologne (2009). Here I did my Ph.D. in exercise science in 2013. In 2014 I worked at the Swedish Winter Sports Research Center as a post-doc. In 2015 I will start a position at the department “Integrative and Experimental Sports Science” at the University of Würzburg (Germany). My interest in exercise sciences started in early years. I´m a former swimmer and triathlete and during my studies, I worked as a swimming coach at a small regional club. At both sides of the pool, I realized how interesting kinesiology really is undefined.
In the literature, a lot of different nomenclatures for high-intensity (interval) training are used. In the study, we published we used different HIT/HIIT protocols during the training intervention in order to keep the motivation of the athletes high. One protocol was 4×4 min at 90-95% heart rate max. with 3 min rest and the other protocol was 2×10×40 s at an intensity corresponding to 90-95 % of heart rate max., with 20 s recovery between the intervals and a 3 min active recovery after the first 10 intervals.
In 2013 Laursen and Buchheit published two reviews about physiological differences between different high-intensity training protocols.
3. What did your study look at?
We investigated how the impact of a HIT session changes after a certain period of only high-intensity training sessions (shock microcycle). The question was if such a HIT shock microcycle causes familiarization effects to this type of training. For this reason, we compared the acute hormonal responses of cortisol, testosterone, hGH, T3, and fT3 at the beginning and after 2 weeks of HIT to investigate whether a habituation effect occurs in these hormones.
4. What were the results of your study?
The most novel finding of this study was that we found a significant increase in the baseline concentrations of testosterone after 2 weeks of HIT. In the other measured hormones (cortisol, hGH, T3 or fT3) we did not observe any significant changes in the response between the first and last HIT session. Additionally, the peak power output in an incremental bike protocol and time trial performance improved, whereas no significant changes in peak oxygen uptake occurred.
5. What were the practical implications for triathletes?
The study shows that a 14 day HIT microcycle can be used to improve peak power output and time trial performance in junior triathletes in a short period of time and that at the end of the microcycle, the training stimulus produced by HIT was still great enough to “stress” the athletes.
6. Do you think the results would be different if you had older, elite or untrained swimmers? + 7. What do you think of high-intensity training for swimmers?
I would expect comparable results for swimmers. The difference here might be in the differences of total training amount between old, elite and untrained swimmers. For elite swimmers, it is crucial to include HIT to improve performance, but with their extremely high total amount of training the coach has to be very careful not to provoke overreaching and/or overtraining.
There are some scientific studies about the results of HIT for swimmers. Sperlich et al. (2010)
investigated HIT in young swimmers and Faude et al. (2008)
investigated HIT in older, competitive swimmers. Both studies showed positive results in regards to performance for the swimmers.
8. What do you think of traditional training compared to HIT in swimmers?
I think it is extremely important to implement HIT into a swimmers training in order to improve performance. In Germany, many swim coaches and swimmers are very eager to cover as much distance as possible during their training. But in the last years, a lot of studies have shown, that both training concepts (HIT and high volume training) are important parts of successful swim training.
9. Who is doing the most interesting research currently in your field? What are they doing?
The group of Martin Gibala
is doing a lot of research in the field of high-intensity training. They are looking at muscular adaptations of HIT, which is a very interesting field of research.
10. What research or projects are you currently working on or should we look from you in the future?
We are working on the implementation of high-intensity training for different populations. On the one hand for obese people who are not able to run or even to cycle and on the other hand for elite athletes. Furthermore, the knowledge about “long-term” effects of different training concepts is very rare. We are trying to get a study started which investigates the effects of different training strategies for at least one season.