Does Muscle Slow You Down?

By on September 29, 2015

People give a lot of reasons for not wanting to start working out and some of these are certainly more legitimate than others.

For those who are interested in training mainly to improve their athletic and physical capabilities, one of the more common concerns is that building lots of big muscle will cause them to become slow and cumbersome. I myself used to use this excuse not to train my legs (I was 18, give me a break) because I wanted to ‘stay fast’.

This scene is relevant, for anyone who never watched Dragon Ball Z...

This scene is relevant, for anyone who never watched Dragon Ball Z…

So the question is, is there any logic behind this?

Muscle Fiber

The best answer to this question is the usual: yes and no. This may be a disappointingly ambiguous answer but it also happens to be the truth – as there are many different factors involved, each of which play a role in our strength to speed ratio.

One consideration for instance is muscle fiber. Those who understand a little about muscle physiology for instance, might be familiar with the concept of ‘slow twitch’ and ‘fast twitch’ muscle fiber (and then type IIa and type IIx). These different types of muscle fiber are responsible for our long term endurance and our fast, explosive movements respectively. As you might imagine, the fast twitch muscle fiber is the kind that is most responsible for our faster and more explosive types of movement. In keeping with this, sprinters have considerably more fast twitch muscle fiber when compared with distance runners (1).

What’s interesting and relevant about this, is that fast twitch muscle fiber is also the kind that grows the fastest and that contributes most to the appearance of large muscle. And guess what else increases this type of muscle? Weight lifting. That’s an explosive movement – especially when you’re lifting big numbers.

So quite contrary to the image of the bulky and slow bodybuilder, those with more muscle mass should actually have more capability for explosive and rapid movements. After all, muscle equates to power and more power allows you to generate more acceleration over a smaller distance.

Plyometric training is even better – training that evolves leaping off the ground during clapping press-ups or box jumps. This increases jump height, acceleration, direction changing and more – and it builds bigger muscle!


But it’s not all good news for the muscular.

One downside of thick muscle is that it creates a relatively constant tension. That is to say, that if you have large biceps, you likely also have large triceps. These are your ‘antagonist’ muscles: the muscles that perform the opposite function and that pull in the opposite direction.

Now unfortunately, if you have massive triceps, this can prevent your bicep from operating as quickly as it possibly could. Likewise, if you massive lats, these can slow down your punches. The same thing goes for your legs.

Muscle is strong and stiff and as such, having more of it means there’s more resistance against all your movements.

Interestingly, an ‘old time’ strongman named ‘Maxick’ claimed to have a solution to this problem that he dubbed ‘Muscle Control’. His claim was that he could create tension only in the muscles he was using at the time, while simultaneously allowing the others to relax. In other words, he could perform a bicep curl while relaxing his triceps and this allowed him to exert more force with the same amount of strength in the biceps. Theoretically this kind of muscle control could be applied to running and all kinds of other activities.

Pavel Tsatsouline meanwhile, claims that a similar strategy can be applied to stretching: that by relaxing the muscles and preventing them from spontaneously contracting, you can quickly gain more flexibility.

So perhaps this type of muscle ‘slowness’ could be overcome with the right training? Nevertheless, for the average Joe, this is a consideration that needs to be taken into account.

Oxygen and Exhaustion

If you’re talking about going for long runs, then there is another way in which muscle could slow you down: simply by causing you to become exhausted more quickly.

Maintaining muscle is a lot of work for the body and requires a constant supply of oxygen and energy. So if you’re a massive bodybuilder, then you’re likely to start feeling tireder more quickly than someone light when running the marathon even if you actually train more frequently.

Another issue to consider in this regard is simply that muscular people are heavier. The heavier you are, the more weight you have to move – and this makes you slower. Every little bit counts – like stripping out the interior of a car you intend to take drag racing (probably…).

The latter problem can be overcome to some regard by using bodyweight training. This can help train your ‘strength to weight’ ratio, such that you have a greater command over your own bodyweight. Likewise, strong man training and using other techniques to increase motor unit recruitment can also help you to be stronger without being heavier. Think Bruce Lee rather than Ronnie Coleman.

As for energy consumption, increasing mitochondrial function, VO2 max and cardiovascular fitness will have some positive effect. You can do this with the right training (HIIT may be useful) and the right diet and supplements (though bear in mind that creatine adds water weight!).

But at the end of the day, there will always be some degree of trade-off. Ultimately, you need to make the decision and choose between a little extra strength, or a little more cardiovascular endurance. Don’t get this twisted though – explosive speed requires muscle. Just try and keep it light and remember that efficiency is the name of the game. Make the most of what you have before you obsess over adding more.

About Adam Sinicki

Adam Sinicki, AKA The Bioneer, is a writer, personal trainer, author, entrepreneur, and web developer. I've been writing about health, psychology, and fitness for the past 10+ years and have a fascination with the limits of human performance. When I'm not running my online businesses or training, I love sandwiches, computer games, comics, and hanging out with my family.

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