What I have always enjoyed about our field of Performance Training is that the research has proven many things to be true or untrue.
One statement we know to be true is that the body produces growth hormone as a response to vigorous exercise, whether that be in the weight room or on the track.
When I came across this article looking at growth hormone responses from treadmill sprinting in sprint trained and endurance trained athletes, I thought it checked off a ton of boxes…
Those who have motorized treadmills in their facilities can see value
Those who work with distance-based athletes can see value
Those who work with sprinters can see value
Like I mentioned, lots of boxes are being checked here. So without further ado, a little bit shorter of an introduction to this Research Review, let’s dive into the literature…
If you’re new here, here’s how these research reviews break down…
Part 1: What we know.
This is going to explain what the research was looking to study, how they studied it, and why you should care.
Part 2: Any comments or concerns about what the study is showing?
Sometimes the best research study looks so good on paper, but then when you dive in you see that it was done on olympic athletes, or was sponsored by a specific company, or something else that can throw a major red flag on its effectiveness in practical use. Alas, that is what we are for here at Parisi HQ
Part 3: How can I use this?
This part is going to explain practical applications of the research. Typically research is lab based and can be hard to replicate when you’re a Performance Coach on a budget. I’m going to do my best to break down how you can actually apply this research to you coaching
Here’s the article of note, in citation format for you grammar nerds out there…it’s hyperlinked to the text in case you want to dive in yourself.
**This link takes you to a research synopsis of the article, a different membership is required to have full access
Part 1: What we know.
This study looked at the growth hormone response to treadmill sprinting in both a male and female population of sprint and endurance-trained athletes. The total population consisted of 11 sprint-trained individuals (5 males and 6 females in case you were wondering) and 12 endurance-trained athletes (split evenly 6 males and 6 females). Athletes performed a maximal 30 second sprint on a treadmill and the group conducting the research looked at peak power and average power expressed in wattage.
The outcome of the study showed that sprint trained athletes produced higher wattage (duh, because specificity…) than their endurance based counterparts. Serum growth hormone was greater in sprint trained athletes than in endurance based athletes, but was not statistically significantly different between the men and the women.
I found that last tidbit of information to be pretty substantial. It is largely considered that one of the biggest differences in male versus female output is contractile properties in the muscle. Seeing the growth hormone response be relatively neutral to gender from sprinting really bucks that trend and thought process.
Getting back to the study…
Plasma ammonia and blood lactate concentrations were higher and blood pH was lower during 1 hour of recovery after the sprint in the sprint trained population when compared to endurance trained population. The last major finding was that growth hormone was still approximately ten times the baseline value in sprint trained athletes after 1 hour of recovery!
Part 2: Any comments or concerns about what the study is showing?
My comments on this study are the opposite of concerns. I really enjoyed that this study used wattage (i.e. an output metric) that is easily obtained through the machine implement being used. In a lot of studies I looked at, especially those that used sprinting as the exercise to induce the growth hormone response, the researchers used Vo2 Max as a measurable output. I don’t know about you, but I don’t have access to mobile equipment that measures Vo2 Max, let alone with a group of 8-12 athletes. Being able to track wattage as a metric throughout a structured sprint training program is easy enough as this is a standard output on every cardiovascular training machine.
One study I would like to see is how growth hormone levels change through different cardiovascular implements. For example, how growth hormone responses compare to free sprinting on a track versus a motorized treadmill vs a non-motorized treadmill vs. a fan bike, vs a standard spin bike. Seeing that we all (probably) have access to a variety of equipment that can be of great use to an athlete depending on their athletic competition calendar, it would be a major benefit as a Performance Coach to see/know the differences between response levels and implement.
Part 3: How can I use this?
The main takeaway – from my point of view- is that the exercise-induced increase in growth hormone can/could have important physiological effects in athletes who partake in a structured sprint program. Those benefits can include increased protein synthesis as well as the sparing of protein degradation leading to maintained or increased muscle mass if the athlete had to partake in a weight loss phase for their sport (think weight class management).