Have you ever wondered why sprinters have a more developed musculature, unlike marathon runners? Sprinting, as a running discipline, has always been linked to athletic development. However, there is a significant overlap between sprinters and bodybuilders (regarding the pursuit of stronger legs), even though their disciplines seem in every way disparate.
Sprinting is a type of speed work, which is not the primary muscle growth method, but it does speed up the hypertrophy process, bringing you much faster to your size destination.
So, what is the relationship between sprinting and hypertrophy? Mona Esbjarnsson, assistant professor at Karolinska Institutet in Stockholm (Sweden) asked herself the same question. Esbjarnsson, along with her team, conducted a research. Nine men and eight women (aged 20-30) performed three successive Wingate tests, and the result noticed an increased Akt/mTOR signalling in the skeletal muscle.
The Wingate test is an anaerobic test performed on a cycle ergometer (stationary bike), which is considered one of the hardest research protocols. Muscle biopsies were taken before the first sprint, and 140 minutes after the final one. The subjects’ blood was drawn before the first sprint, between each sprint, and 9, 80, and 140 minutes after the last one. What they found was this:
- There is no major difference between men and women regarding their power output. This negates body fat differences. The results also negated major fiber type differences between the two subject groups, so the only influencing factor remained to be the gender.
- The results regarding mTOR (mechanistic target of rapamycin; binding protein which regulates protein synthesis and cell growth, proliferation, motility, and survival) phosphorylation, AMPK phosphorylation, levels of plasma leucine, lactate and plasma lactate there were no significant differences between women and men.
- As for the hormones which promote muscle growth, glucose and insulin, there were no considerable differences between genders, and their levels increased in response to the exercise. However, the increase of glucose was larger in women, and the increase in insulin was about 5x above the baseline (women) and 3x above the baseline (men). The peak values of growth hormone values were not significantly different, although the levels were higher during rest time for women.
- A strong correlation between P7056k increase and insulin increase was noted in the post-exercise period.
It is implied that the energy status of our cells has a lot to do with hypertrophy response to a physical stimulus.
Here is what speed work can do for you, if you put some effort into it, with some help from a personal fitness trainer:
- It prevents fat gain. Sprinting is one of the best exercises for losing fat stores and increasing muscle size. After your training, post-exercise oxygen consumption is increased, and your calories are then burned more quickly.
- It improves anaerobic conditioning levels. Sprinting can ensure alactic and lactic (energy support) systems, that fuel the hypertrophy training zones, to perform at optimal levels.
- It functions as supplemental hip training. The most dominant muscle groups in sprinting are the hamstrings, which makes sprinting a good hamstring strength test. If you combine your training with this type of speed exercise, you will address the posterior chain weaknesses, and employ this area maximally during your lift training.
- It is a form of progressive overload. Sprinting is a form of resistance, but not a common one such as dumbbells, barbells and kettlebells training. What makes sprinting different is the momentum of our body mass, which is then another crucial source of overload. During a sprint, the landing impact can exceed 3 times your body weight. If you multiply this with the number of foot contacts during a sprint, you will see the real muscle growth benefit and the challenge of sprinting.
- It strengthens fast-twitch fibers. Fast-twitch fibers are those responsible for explosive, fast movements such as sprinting. On the other hand, they do not possess the endurance-boosting ability like slow-twitch fibers. Because of this, they can be used for short periods of time.
Sprinting increases protein synthesis for up to 200 percent. With the right muscle recovery and proper nutrition, sprint exercises will lead to building muscle mass. As you may have noticed, sprinters have a quite lean physique, and are very muscular, even without performing resistance training. All the conditions required for muscle growth (high eccentric contractions, volume-fatigue, and general overload) are present during sprint exercises. Unlike sprinters and their lean figure, power lifters also incorporate speed work in their training routine.
It is called Dynamic Effort Work, and it helps them gain more mass, prevents stagnancy, and increases force production.