Sprint Training- Speed that Lasts

Swimming slowly is not nearly as fun as swimming fast! So let’s start talking about how to develop that speed. If you haven’t noticed yet, we like to ask questions before we answer them: What is Sprinting? Should be easy enough to answer… top swimming speed, right? That’s only half of answer. A high top speed that can’t be sustained isn’t going to help us win any races. We have to make the top speed last. Sprint training therefore, focuses on these two pillars: developing top speed with Speed training, and making it last with Lactate Tolerance training.

Just like with endurance training, there will be overlap in the adaptations your Swimming Machine makes when performing either type of training. But to keep things simple and organized we have divided out the two training types and what they mostly stimulate to adapt.

Speed Training: Nerves and Muscle Angles

In our Introduction of the BOS-I, we said that the swimmer who wins is the one with the best Power to Drag ratio. Speed training is all about working on the ratio. The sets we use for this involve very short sprints (less than 30 seconds) with long rest, about 1:4-6 ratio of swimming time to rest time. By the science, it takes about 1.5 minutes for the creatine phosphate (ATP and phosphagen system) levels to return to normal after a sprint, so that is about your rest time. For instance, 12x25 @ 1:00 2 fast/ 1 EZ. Obviously, the goal is to hit your top speed on the fast 25s. If you speed starts to go down, that means the acid is building up and you are entering Lactate Tolerance mode and need to take a longer break. For Speed Training, we don’t want the acid to build up… all we want is speed!

Tangent: The energy system name for this training is SP-3.

I know what you’re thinking, speed training is just like weightlifting and will make my muscles bigger and stronger and therefore I can make more power and go faster. Nope, not really. If you went from being a total couch potato to doing any type of training, then sure, your muscles will grow and develop. But when we just talk about already trained swimmers, Speed training won’t change muscle size much. Making muscles bigger, called hypertrophy, requires the muscle cells to be damaged by either eccentric motions (contraction + lengthening) or by an overload of acid (next section).

Speed training is more about training the nerves that control your muscles. In order to maximize the Power: Drag ratio, we need to develop more power with the same amount of muscle, we need to direct that power in a more efficient way, and we need to decrease our drag as much as possible because the faster you move through the water, exponentially more drag will be created.

Let’s start with generating more power with the same muscle mass. I’m sure your remember from our Motor Unit chapter that muscles are made up of millions of cells, called muscle fibers, that are arranged in bundles of 10 to 1000 and called motor units (group of muscle cells + the nerve that controls them). You definitely also remember that motor units are arranged to contract based on the power needed by the whole muscle. Lower threshold motor units are made of slow twitch fibers and contract when low power is needed, and higher threshold motor units are made of fast twitch fibers and contract WITH the slow motor units when a lot of power is needed. Here’s the picture to remind you:

This process of adding on motor units is called recruitment, because as power necessity goes up, the Swimming Machine “recruits” more motor units to get the job done. With Speed training, we are recruiting everything… or at least, we are trying to. Speed training improves motor unit recruitment, which means generating more power with the same exact muscle mass… sweetness.

Here are two examples to show you how powerful this. My personal experience with this was when I was a competitive powerlifter. At first, I weighed about 170lbs and was able to deadlift about 300lbs for a one-rep max (that means I could pick up 300lbs just one time). A few years later, after much training and competing, I still weighed 170lbs but was able to deadlift 600 (and then I promptly retired). How is that possible? I wasn’t fat to begin with, my body was the exact shape and size it was when I was deadlifting 300. The answer is recruitment. I trained my nerves to fire up all available motor units and lift bigger weights. Another example is with hypnosis. If you hypnotize an untrained person and merely tell them they are stronger, they can lift more weight right away. However, if you do the same thing with trained athletes, they don’t get stronger (sorry, it was exciting for second). The theory is that untrained people have not “unlocked” their neural safeguards like trained athletes.

Why does the body have these neural safeguards? If you were untrained and fired every motor unit you had you would end up hurting yourself by snapping tendons, muscle fibers and ligaments. Speed training desensitizes these neural safeguards and improves recruitment as you build the connective tissue support required to handle all that power. In summary: Speed training can increase high-threshold motor unit activation, keep them contracting for a longer time, synchronize them better with lower threshold units, decrease neural inhibition and produce an overall improvement of force by 300-1500%! That’s right, you can generate up to 15x more power with the same exact muscle mass you have right now, that’s what I call improving Power and keeping the drag (bodyweight) low.    

Tangent: Electrical Muscle Stimulation is when you run electricity on the skin to activate the muscles underneath. It’s not great for training because it is not specific at all, but it may be a good supplemental training (especially if you are hurt). It preferentially recruits fast twitch fibers, and can cause greater than voluntary contraction ability! Ouch.

Generating a lot of power is great, but sending that power in the wrong direction isn’t going to help anyone get across the pool any faster. We will talk about reducing drag and building motor patterns (technique) in just a second, but what I’m talking about here are the muscle fiber angles.

You may have noticed that most muscle fibers are not perfectly in line with their tendon. Instead, they attach at an angle, and the muscle fiber is sitting diagonally from the tendon, and therefore is not directly in line with the direction of joint movement and whole muscle shortening. It’s kind of like playing Tug-of-War, but instead of standing right next to the rope, you’re actually standing a foot to the side, and your arm is reaching towards the rope at an angle.

Something doesn’t sound right… isn’t pulling at an off angle less efficient than pulling directly in line with the movement of the joint?! Yup, you’re right. But there is an advantage here. By creating this angle, you can squeeze in more muscle fibers in the same area and still have them all attaching to the same tendon (which is essential). This increased density allows way more force to be generated and it allows a greater shortening length of the entire muscle. While every muscle in the body has specific genetic guidelines for what angle they should have, Speed training (and weightlifting especially) can change these angles to better serve the needs of the Swimming Machine. By training at race speeds and with 100% power, muscle fibers can “re-orient” themselves and their direction to apply their force in a better direction.

The more in-line the muscle fiber is with the tendon it attaches to, the faster a muscle can shorten. The less in-line it is, the more force that can be generated. In addition to changing the muscle fiber angle, each individual fiber can add sarcomeres to itself. These sarcomeres can be added to the ends of the fiber to create a longer muscle that shortens quickly. Or they can be added side by side of other sarcomeres to create a fatter muscle that shortens more powerfully. This is one of the reasons why weightlifters have bulky, short muscles. And sprint athletes have long, slender muscles. This goes back to our first chapter on Muscles. Nice to see things come full circle!

So, what kind of changes to the muscle fibers do we want and how can we get them to help us swim faster? Ideally, we want long, slender, fast shortening muscles angled in a way that is most in-line with the tendon. This will generate the fastest shortening muscle possible. Getting those changes is simple, train those contractions in the same way you need them to change. That means Speed training! To see how these changes affect our swimming, we can take a look at a study done outside the water. The experiment involved training the legs by doing leg extensions. Each leg was trained at a different angle and by the end of the experiment, strength was improved, but only for the angle that was trained and no others! By training at full swimming speeds and power, we do the same thing and improve our own muscle strength over the entire length of the stroke cycle.

Tangent: Taller people with longer bones makes the angles smaller in the muscles. That makes sense. If you have 3 feet of muscle that needs to shorten, we don’t want it to take forever to contract.  

These change also have a downside that we need to be very cautious about. Any training performed that is not specific to your swimming stroke will cause these muscle fiber changes to adapt in a way that is not for swimming. For instance, pullups are a common dryland exercise to help improve that Lats muscles. They will improve those muscles for sure, but that “pullup” motion is not something we do in the water… like ever. So by doing pullups, we are changing our muscle fiber structure to help us do pullups, not the actual swimming pull. A more specific exercise would be to do straight arm pulldowns, since this replicates the arm motion that we do in the water. It has even been proven that body orientation while doing certain exercises affects the transfer of training adaptations from the weight room to the athletic event. That means doing straight arm pulldowns while lying down is better than doing them standing up. We will talk more in the Dryland chapter, but these concepts apply to Speed training in the water as well.

The final way Speed training improves our Power to Drag ratio is by adapting our motor patterns… better known as technique. In our next chapter we will discuss this process of changing motor patterns in greater detail. For now, we need to understand that when an entire muscle contracts for a specific reason, say the freestyle arm pull, there is a specific sequence in how the motor units and muscle fibers are activated. This is not conscious, but is written like a program into the parts of the brain that store these “motor patterns” by continuous communication back and forth between the muscles, joints and brain. Training at full speed helps build these motor patterns. The communication between muscles and the brain is constantly being analyzed and altered to improve performance and adapt the Swimming Machine to better move through the water. This means adjusting tempo, rotation, timing of arms and legs, breathing, co-antagonist muscle activation to improve joint stability and force application… on and on and on to everything you can possibly think of that makes up your top speed technique. If you don’t train at top speed, these motor patterns won’t improve. And when your entire body is constantly changing, growing and being improved through training, these motor patterns need to adjust continually to maintain the optimum stroke technique, and therefore the optimum Power to Drag ratio!

Tangent: Let’s say we train curls, but just with the right arm and not with the left. After a few weeks, the right arm would improve, let’s say 36% improvement. Without training however, the left arm would also improve by about 24%! What!! Something crossed over through the brain. And it’s not just nerves that get trained, but enzyme changes inside the muscle cells as well. This works best when contraction is maximal. Good for rehab.

Lactate Tolerance: Buffering and Hypertrophy

Lactate Tolerance… just hearing those words gives us a sense of dread. Let’s figure out why these sets are so important, maybe that will help us stay motivated to do them regularly. The goal of a Lactate Tolerance set is to generate and overload the muscle cell with as much acid as possible by swimming all-out for longer than 40 seconds, but no more than 2 minutes because then it is an aerobic set, not a Lactate one. Rest intervals are long as well, about 1:3-4 ratio of swimming to rest time. A sample set would be 6x100 @ 6:00 All-Out! If done right, it should hurt… a lot.

Tangent: Other names for this training are SP-1/2 and punishment and self-torture.

During the set, lactate and acid (interchangeable terms for our purpose) reach maximum levels and cause the muscle’s pH (acidity level) to drop and will actually prevent the myosin heads from interacting with the actin and therefore will stop muscle contraction by force. Heart rate maxes out, all motor units fire initially, but then drop out from the top down due to lactate overload, and full racing technique is practiced during this set. So what does this signal our Swimming Machine to change? Muscle enlargement and buffering capacity (called Slykes). And just like Speed training, Lactate Tolerance sets give us a chance to work on those motor patterns and race strategies that are so important for successful swimming.

Getting swole! Finally, I got your attention. So why do Lactate Tolerance sets cause muscle enlargement? Anything that causes damage to the structure of the muscle itself will cause the muscle to grow in size. In athletics, this is caused by new exercise training, eccentric training, and damage by acid (anything that makes you sore). This growth is termed hypertrophy, as in hyper = increasing and trophy = growth. Growing muscles do not undergo hyperplasia (plasia = number) however, which is growth by increasing the number of muscle fibers that exist. Instead, you have the same number of muscle fibers at all times, and those individual fibers get bigger.

Tangent: Hyperplasia occurs a little bit when muscle cells are damaged to the point of death. Satellite cells are the “stem cell” precursors to new muscle. Some evidence exists to say human growth hormone (HGH) can cause hyperplasia of muscle as well.

The signals that cause muscle cells to swell up in size achieve their task by creating more proteins that make up the muscle cells like actin and myosin. These growing muscles create new sarcomeres, cytoskeleton, and connective tissue that accounts for the change in size. Obviously, with more actin and myosin available to interact, this will increase the power that muscle fiber can generate. Weightlifting is the obvious idealism of making muscles swole, and as little as 6 months of training will cause a 30% growth in muscle size! Swimmers, however, are not that jacked. That is because the signals coming from Lactate Tolerance sets that cause anabolism (growth) are countered by the signals generated from Endurance training which maintains smaller muscles by using these newly formed proteins as fuel. This balance of creating and destroying proteins is occurring all the time. When the balance is shifted to one side, say when weightlifting or doing Lactate Tolerance, then the muscle grows.

Both fast and slow twitch muscle fibers have the ability to grow in size. Take powerlifters and bodybuilders for example. Powerlifters focus on improving their 1-rep max lifting ability by picking up very heavy things for very few reps (just like Speed training). This focuses in on fast twitch fibers. Bodybuilders however, only care about looks and size. Their training involves lifting lighter weights for a huge number of reps, well past failure (just like Lactate Tolerance sets). This focuses on slow fibers. At the cellular level, powerlifters have fast muscle fibers that are twice the size of their slow ones. Bodybuilders, surprisingly, cause massive hypertrophy of their slow fibers. Slow fibers require much more blood flow might explain why bodybuilders get so veiny, all that blood has to go back to the heart somehow. This shows that even different Sprint training types will affect different muscle fibers.

So what do we swimmers want to mimic, powerlifters or bodybuilders? As usual, the answer is both. Swimming is the sport of balance, very rarely do we want or need to be too one sided. Swimmers want big slow twitch fibers (created through Lactate Tolerance) that fire all together with their fast twitch counterparts to generate lots of power (Speed training). This will get us the benefits of the efficient aerobic power of slow fibers, and the strength of fast fibers.

What effect does all this growth have on our hybrid engine, on our Energy Systems (review in BOS-I)? Actually, very little. We talked about the changes that mitochondria undergo with Endurance training, but Sprint training does not change mitochondria or capillaries at all. And because the muscle cell is growing in size, the mitochondria and capillaries spread out and get diluted within the muscle cell. That means Sprint training and muscle hypertrophy causes a decreased mitochondria and capillary density, as much as a 25% decrease!

Whoa, that does not sound good for us swimmers, won’t this kill our endurance ability? If hypertrophy is overdone, like with too much weightlifting in the off-season, then yes, endurance might go down. But for the most part, when Endurance training is maintained, mild to moderate hypertrophy won’t cause a decrease in endurance performance. That’s because mitochondria sit out on the edge of the muscle cell near where the capillaries are, so they still have access to all the oxygen they need to keep making ATP at a high rate.

Glycolysis (our other, more powerful engine) also doesn’t change much, kind of… This engine is really just a set of enzymes that float around the muscle cell, it is not a localized factory like a mitochondria. That means glycolysis works by density. The more enzymes lying around, the better this engine works. Even at baseline, glycolysis can produce a lot more ATP than the muscle needs, while also creating a lot of acid. For that reason, glycolysis enzyme densities don’t really improve with Sprint training since they are essentially maxed out already. As the muscle cell grows in the size, the density of glycolysis enzymes is maintained. So yes, in a way glycolysis is improved when the muscle hypertrophies since there are more enzymes floating around, but the density of these enzymes is the same as a small muscle fiber.

The final signal sent out by Lactate Tolerance sets have to do with dealing with the lactate itself. The overload of lactate also signals the creation of more lactate transporters to get rid of the bad acid, but we already talked about that in the Endurance Training chapter, under Aerobic Power. The other way acid can be dealt with is by buffering. Acid, whether it comes from glycolysis, stomach acid or where ever is really just a free floating hydrogen atom.

The concentration of hydrogen atoms is how we get our pH number. These free floaters can also be attached to other molecules and taken out of circulation. This process is called buffering. Many molecules in the muscle cell can act as a buffer: bicarbonate, creatine phosphate and proteins in general. With Lactate Tolerance training, the ability of the muscle to buffer acid improves because more of these buffers are created and float around to absorb the excess hydrogen atoms created. In fact, lactate levels (and therefore hydrogen levels) can increase 4-5 times their normal levels before muscle pH will drop. That means all of that acid was buffered and also means you can maintain that top speed and maximum glycolysis for much longer. That is good news if you are trying to out-touch someone at the end of a 100 freestyle!

Tangent: The quantitative measurement of a muscle’s ability to buffer acid is called a Slyke. The proof that Slykes were a trainable ability was done in cyclists who performed 8 x 30s all out cycling bouts, four days a week, for 8 weeks! That is a lot of sprinting and a lot of pain… we thank those poor volunteers for their sacrifice.

That brings us to the end of Sprint and Endurance training. Hopefully by now you have a better understanding of how the sets we do in practice make real, physical changes to your Swimming Machine that results in your next best time. Go out there and attack the next workout!