Introduction
Anyone that is looking to get faster will no doubt find a variety of exercises being shoved at them upon searching the web. However, can these be backed by science?
People also often associate being a sprinter with being jacked, but which muscles are actually important for speed?
It seems as though the most important muscle for speed and sprinting is the gluteus maximus. Although of course many muscles are important for sprinting, a recent research study suggests that a well developed gluteus maximus may be the largest differentiating factor between elite and sub-elite sprinters.
How Do We Know Which Muscles Are Important?
There are two main methods for determining which muscles are important for sprinting. We can deduce which muscles are important based off a theoretical model of how the body sprints.
However, it is better to figure out which muscles are important for speed experimentally. This can be done by comparing the musculature of elite sprinters and non-sprinters.
Obviously, if there is a big difference in certain muscles between these groups, then we can say that it is likely the case that these muscles are important for sprinting.
The latter method is a more reliable than the first, as in the first case our theoretical model may be flawed. Indeed, many studies have chosen to compare the musculature of elite sprinters vs non-sprinters in an attempt to elucidate which muscles are the most important.
“The Muscle Morphology of Elite Sprint Running” – Research Paper
Today we are going to dive into one of these studies. The title of the study is “The Muscle Morphology of Elite Sprint Running”.
This study is quite recent, being published in 2021. The study is also interesting as it compared elite sprinters to non-sprinters as well as sub-elite sprinters.
This is appealing since previous studies typically only compared sprinters to non-sprinters, whereas this article compares three distinct groups.
Now let’s get into the research article.
The study we are going to be discussing herein
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What Did the Researchers Do?
As mentioned, the researched collected data on three distinct groups: non-sprinters, sub-elite sprinters, and elite-sprinters.
The non-sprinter group consisted of 11 people that did not participate in sprinting or sprint training. The sub-elite sprinter group consisted of 26 sprinters whose season best 100m time was between 10.50 and 11.10s. The elite-sprinter group consisted of 5 sprinters whose season best 100m time was between 10.03 and 10.17s.
The researchers then determined the muscle volume size of 23 different lower-body muscles using MRI scans. They also tested the isometric strength levels of various lower body muscle groups.
What Did the Researchers Find?
The researchers found that, unsurprisingly, the total lower body muscle volume was higher in the elite sprinters than the sub-elite sprinters which was higher than that of the non-sprinters. In other words, the faster athletes had more total lower body muscle volume.
However, importantly, some muscles were more important than others.
For example, the plantarflexors (such as the gastrocnemius, soleus etc… or, roughly speaking, the calves) showed little difference between sub-elite vs elite sprinters.
The Biggest Difference Between Sub-Elite and Elite Sprinters
Now for the important part.
There were three muscles in particular that were consistently different between sub-elite vs elite sprinters. These were the tensor fasciae latae (TFL), sartorius and gluteus maximus.
The sartorius (left) and tensor fasciae latae (right) muscles.
You may not be familiar with the first two, which are involved in hip flexion (raising your knee up closer to your chest). The gluteus maximus is probably more familiar, it being by far the largest of the ‘glutes’.
The gluteus maximus works together with the hamstrings to extend the hip (meaning to extend your leg backwards behind you when standing or to bring your hips forward after being crouched down. Think of the movement of your hips when you come up from the bottom of a squat – that is hip extension).
Indeed, the hip extensor muscles showed a large difference between the two sprint groups.
Rather surprisingly, the gluteus maximus alone accounted for up to 44% of the difference in sprint times between the sub-elite and elite sprinters. Needless to say, this study concluded that the volume of an athlete’s gluteus maximus is extremely important in explaining the difference between sub-elite and elite sprinters.
Consistent with other studies, this study also found that the muscles of the hamstring were generally bigger in elite vs sub-elite sprinters. However, not to the extent of those muscles previously mentioned.
A table summarizing the data can be seen below:
A table summarizing the differences in lower-body muscle volume between all groups. Sartorius, TFL and Gluteus maximus rows have been highlighted.
This MRI scan uses some individual examples to more visually show us the difference in muscle size between the groups.
An MRI scan showing the difference in musculature between an untrained, sub-elite and elite sprinter.
Isometric Lower Body Strength – Elite vs Non-Elite
Another surprising result of this study was that – while both sprint groups were stronger than the non-sprint group – strength differences between the two sprint groups were negligible.
In other words, the elite sprinters did not perform better on the isometric strength tests than the sub-elite sprinters.
The authors theorized that this could be due to the highly specific nature of sprinting. During top speed sprinting, elite sprinters will only contact the ground for ~0.08-0.09 seconds. This is very different from the types of isometric strength tests used in this study.
Elite and sub-elite sprinters may have similar strength levels in the context of the tests in this study. However, elite sprinters are of course more likely to be stronger when it comes to the time frames involved in sprinting.
What Can We Learn?
So, what can we take away from these findings and how can we use them to improve our own speed training?
This study supports the general idea that first you should strive to achieve a ‘base level’ of strength and musculature. This is shown by the fact that sub-elite sprinters still had a larger volume of muscle and performed higher on the lower-body isometric strength tests than the untrained group.
Hence, if you are a beginner when it comes to general strength and hypertrophy training of the lower body, then it is a good idea to focus on those qualities.
However, if you are already somewhat experienced, then specificity becomes more important. In the context of this article and the study presented here, specificity as it relates to which muscles you should develop.
Of course, the prime candidates are the tensor fasciae latae, sartorius and gluteus maximus.
The first two of these muscles are relatively small and targeted hypertrophy training of these muscles is quite difficult. In contrast, the gluteus maximus is a relatively large muscle and targeted hypertrophy of this muscle is well understood and widely practiced.
Hence, once a general level of strength is achieved, targeted hypertrophy-based training of the gluteus maximus would be a good next step.
Many are somewhat hesitant to focus on hypertrophy-based training due to the fear of increasing your weight. If you increase your weight without a simultaneous increase in power, then you will consequently get slower.
However, this study has showed us that gluteus maximus volume was one of the most important variables when it comes to explaining the difference in sprint times between sub-elite and elite sprinters.
So, consider incorporating some hip thrusts, RDLs or deep squats into your gym routine if you’re aiming to increase your speed.
The main findings of the study were:
- In terms of total muscle volume, elite > sub-elite > untrained
- The biggest difference between elite vs sub-elite sprinters was volume of the sartorius, tensor fasciae latae, and gluteus maximus
- Gluteus maximus volume alone explained 34% to 44% of the variability in 100m sprint times
- In terms of lower body isometric strength, elite = sub-elite > untrained
So, what can we take away from these findings and how can we use them to improve our own speed training?
This study supports the general idea that first you should strive to achieve a ‘base level’ of strength and musculature. This is shown by the fact that sub-elite sprinters still had a larger volume of muscle and performed higher on the lower-body isometric strength tests than the untrained group.
Hence, if you are a beginner when it comes to general strength and hypertrophy training of the lower body, then it is a good idea to focus on those qualities.
However, if you are already somewhat experienced, then specificity becomes more important. In the context of this article and the study presented here, specificity as it relates to which muscles you should develop.
Of course, the prime candidates are the tensor fasciae latae, sartorius and gluteus maximus.
The first two of these muscles are relatively small and targeted hypertrophy training of these muscles is quite difficult. In contrast, the gluteus maximus is a relatively large muscle and targeted hypertrophy of this muscle is well understood and widely practiced.
Hence, once a general level of strength is achieved, targeted hypertrophy-based training of the gluteus maximus would be a good next step.
Many are somewhat hesitant to focus on hypertrophy-based training due to the fear of increasing your weight. If you increase your weight without a simultaneous increase in power, then you will consequently get slower.
However, this study has showed us that gluteus maximus volume was one of the most important variables when it comes to explaining the difference in sprint times between sub-elite and elite sprinters.
So, consider incorporating some hip thrusts, RDLs or deep squats into your gym routine if you’re aiming to increase your speed.
Power athletes and coaches love to debate about what the appropriate squat depth should be. Some argue that lower depths achieve body positions that are more specific to their sport (such as when coming out of the blocks for a sprinter). However, this article seems to indirectly support training squats at a greater depth, as deeper squats result in greater gluteus maximus activation.
Also, don’t be afraid to go into higher rep ranges (8-12). You don’t have to stick to a rigid 5×5 program for example out of a fear of hypertrophy.
Conclusion
The study considered in this article tells us that gluteus maximus volume is extremely important when it comes to sprinting at a high level. However, if you are beginning, then focusing on a more general approach to training is advisable. If you are more experience, then targeted hypertrophy training – specifically of the gluteus maximus – may be an important element of training for those wanting to get faster.
As always, studies like this have their limitations. A notable one being that only 5 elite sprinters were tested (there really are not that many in the world!). There are of course many other elements of sprint ability other than muscle size, so don’t expect to make big improvements through only spamming hip thrusts. Nonetheless, this study does highlight one important, and potentially overlooked, aspect of sprint performance.
