Cross country season is finally upon us. With school back in session and competitions beginning, cross country athletes throughout the nation are navigating the issue of whether or not they should be lifting. One doesn’t need to look far to find a range of opinions on the subject. Sport coaches, strength coaches, athletes, researchers, doctors, and therapists often espouse conflicting philosophies backed by the weight of academic or field experience. As a result, lifting weights is typically met with skepticism or outright avoidance by distance coaches and athletes alike.
Apprehension is common in areas that are misunderstood, so I wanted to take the opportunity to release a series of posts providing guidance regarding strength training for cross country athletes. This first post will address the issue with which I get the most concern from both parties when it comes to lifting: fear of gaining weight.
Why Does Strength Matter For Distance Runners?
Before we dive deeper into the risks of gaining weight, we need to establish a foundation for why strength is a valuable quality for distance athletes in the first place. One reason is that strength helps delay fatigue. We can understand how by exploring the biology of the motor unit.
A motor unit is comprised of an alpha motor neuron and all the muscle fibers it innervates within a particular muscle. Each motor unit contains the same fiber type, can consist of hundreds or thousands of individual fibers, and will contract maximally when signaled. Within each individual muscle there are many motor units, and these force-producing groups of muscle fibers are called into use, or recruited, depending on the force required to produce movement.
During low-force movements, smaller motor units made up of mostly slow-twitch muscle fibers can cover the work demand. When the force requirements are high, the body adapts by calling into action additional fibers, known as high-threshold motor-units, that are largely inactive when force requirements are low. These are comprised of higher force-producing, fast twitch fibers.
While distance athletes typically have a greater portion of slow-twitch muscle fibers, they still possess a differentiation between low and high-threshold motor units. What happens in the course of most endurance training is chronic exposure to low-force activities, precluding a significant portion of available muscle fibers from being activated to perform work.
Here is where it gets valuable in endurance training: as the athlete is exposed to the higher forces required in strength training, the body creates neurological pathways to previously untapped high-threshold motor units. As athletes train and compete, these units join the pool of muscle fibers that can be utilized to share in the work burden. Having more available muscle fibers to perform work means being able to sustain a given pace for longer, or a slightly faster pace for the same.
Another benefit as strength improves is that the relative work required with each stride decreases. For example, if I can squat 300 lbs and perform sets at 200 lbs, I’m training at 66% of my strength capacity. But if I can squat 400 lbs, doing sets at 200 lbs is less relative work as it’s only 50% of my capacity.
The same thing happens with the force required in every step while running. As strength improves, running at a certain pace becomes easier as each step requires less relative force.
Strength also serves as a foundation for improving power. The equation for power is force x distance/time, or force x velocity. The importance of power for distance runners can be seen in ground contact times during running. Even during long slow runs, running is a ballistic activity with ground contacts typically lasting less than .2 seconds. With such short ground contact times, it is important to be able to express strength quickly. Strength training alone doesn’t address the velocity component of power, but boosting strength levels improves power by improving the force side of the equation. Additionally, strength is a valuable precursor to specific power training methods like plyometrics that address the velocity side of the power equation, teaching the body to generate force quickly, improving the rate of force development (RFD).
Lastly, increased strength helps reduce injuries as increasing external load is a potent signal for osteocyte (bone) and collagen (tendon) thickening. This can help reduce the risk of stress injuries and tendinopathy- common chronic-overuse injuries to which many distance athletes are prone.
What’s The Big Deal?
With all of the benefits of strength training for the endurance athlete, why is there so much resistance? The primary resistance to strength training stems from the belief that lifting weights will make distance athletes too big to perform well, and the risk isn’t seen as worth the reward..
While this concern can be mitigated, it isn’t unfounded. Without knowing anything else about lifting and how the body adapts, simple observation of the strongest athletes on campus like football players and throwers can create the impression that the more you lift, the bigger you will get. For these athletes, mass is a critical tool; a co-requisite in developing the absolute strength and power necessary to move an opponent or implement while making themselves more difficult to move on the field.
Observe smaller athletes like sprinters and jumpers who lift to improve relative strength and power and you’ll see that even they are more muscularly developed than most distance athletes. Given these obvious observations, it’s easy to see how “lifting weights” equates to “get big” as strength and size are often conflated.
While the concern of gaining mass is a valid concern, it is also one that often rests on a misunderstanding of how the body adapts to training and more specifically, what type of training increases the size of the muscle.
How Do Muscles Grow?
In order for a muscle to grow, three things are needed: First; the stimulus to grow. This comes from training. Second; an anabolic hormonal environment. This comes from genetics, training and other external factors like diet and stress management. Third; enough dietary protein for the body to rebuild itself larger than it was before.
We are going to focus in on the stimulus to grow through training. When it comes muscle growth, or hypertrophy, there are multiple mechanisms involved with the three big players being tension, fatigue, and muscle damage.
Think of tension as how hard you can create a sustained muscle contraction. Generally the higher the weight you use in a controlled matter, the more tension created. This isn’t just dropping down in a squat and exploding up, but squeezing the muscles involved as hard as possible.
Fatigue is probably best thought of as the “burn” you get when you take a movement close to failure for higher reps. This burn is associated with the formulation of lactate and accumulation of hydrogen ions in the blood. This process can initiate hypertrophy by signaling an anabolic hormonal response that helps rebuild muscle tissue.
Muscle damage is perhaps the most potent of the three. The damage, or microtrauma, is most effectively produced by contracting a muscle while it lengthens during the eccentric (down) phase of a movement. The damage created sends the body a powerful signal that protein synthesis is needed to repair the tissue.
These mechanisms all work in concert to create the necessary damage and hormonal environment to stimulate muscle growth. The body adapts by repairing the damaged tissue with the amino acids provided by dietary protein. Assuming enough is available, the body will super-compensate by rebuilding the tissue thicker and more resilient than it was before. While this is a gross over-simplification of the process, it helps us understand the basics of how muscle tissue grows.
Effective training for hypertrophy generally includes methods that address each of these mechanisms alongside a diet complete with the requisite protein. Bodybuilders, who seek to add mass within the confines of symmetry and proportions, often use slower, controlled reps in the 8-15-rep range (though higher and lower rep ranges are used as well) in order to optimize their tension, fatigue, and damage created.
So how do distance athletes get the strength response we want from lifting without the size gain? Fortunately, strength and size are different qualities that can be trained somewhat independently. As a result, resilience and neurological adaptations that improve distance performance can be facilitated outside of the methods that lead to muscle growth. By avoiding training that stimulates growth we can eliminate the feared increase in muscle size while reaping the rewards of increased strength.
Strength vs Size
Strength is simply the ability to exert a force. Practically, force is expressed through the requirements of a specific movement. The magnitude of this force is affected by multiple factors including the athlete’s technical efficiency in the movement being performed, as well as the force-generating ability of muscle tissue. Motor unit recruitment and muscle size are the primary determinants involved in the force-generating capacity of muscle tissue.
It is well established that, all other factors being equal, a muscle with a greater cross-sectional area is capable of generating more force than one with less. While strength and muscle size are certainly related in this sense, technical efficiency and motor-unit recruitment are neurological components of force development that impact strength without increasing muscle size. Remember, as more motor units are called into action, more force is produced. This principle is independent of muscle size
What this means for the distance athlete is there should be an increased focus on training the neurological components of strength and avoiding higher volume methods that lead to muscle gain. The sweet spot for this is by keeping volume low and intensity relatively high on our chosen movements. We see the importance of this idea on display through athletes competing in sports that are divided into weight classes like powerlifting and Olympic weightlifting. With detailed technical training and high intensity work, they can improve performance while minimizing muscle growth to stay within their weight class.
We can apply this same idea when it comes to strength training for endurance athletes: given proper technical execution, it is crucial that the weight be a challenge to lift. This is different than the typical “light weight for high reps” approach that many in the distance realm opt for.
The reason low volume, high intensity weight works is that tension created by lifting progressively heavier loads by itself does little to initiate hypertrophy. It is when tension is sustained and combined with damage and fatigue that it plays the greatest role in muscle growth. When volume is kept low and the weight high, the body is forced to recruit additional motor-units that aren’t typically called into action with normal endurance training. This results in higher force producing ability, but doesn’t cause enough of a stimulus for muscle growth.
Putting It Together
So what does this look like as far as implementation in the weight room? I’ll save the details for future post, but here are a few ideas to help you make decisions.
First of all, intensity is relative to the individual and is highly dependent up technique. While higher weight is an important factor for motor-unit recruitment, the movements need to be done safely. Low-volume, low-intensity training is a poor environment to acquire the motor control and mobility necessary to eventually move higher weight safely. We need more practice reps at the beginning to get familiar with the movement while it is light enough to not stimulate muscle growth.
When learning new movements, I like to stick in the 5-8 rep range and gradually move down into the 2-4 rep range as I increase the intensity. Three or four sets is usually good enough to get the response we are looking for. A couple important notes: technique must stay the same as the weight goes up, and there should always be little left in the tank with whatever rep range you are working in. Going to failure and testing maxes tend to do more harm than good, especially in season.
This approach works great for large compound movements like squats, deadlifts, split squats, and RDL’s.
High-Rep Warning
High-intensity, low volume training is usually a different approach to lifting than what many distance athletes expect. I often hear how “low weight, more reps” or “more core” is what distance athletes need. But this approach can come with detrimental side effects. Remember, higher rep training is what those seeking to gain mass typically perform because it is used to create more fatigue, damage, and keeps them under tension for longer. As previously mentioned, if the weight is kept light it can be useful for a time while learning a new movement. But if weight is added and reps kept high, you end up doing the same moderate intensity, higher rep training that is used specifically to increase muscle mass in athletes who are trying to grow.
The temptation then can be to keep the weight light and add more reps. Afterall, distance athletes run for a long time, so lifting should take a long time too, right?. Wrong. As volume is added, you start to run the risk of interfering with recovery from the running being performed. Lifting is a tool to improve your running training and performance. If the weight room is another round of training the same energy systems that were just worked for an hour on the road or track, recovery can start to be impeded, making it harder to perform the running work. Most of the time this trade off isn’t worth it.
Lastly, many may default to their comfort zone and not add weight or reps, doing the same routines repeatedly. The problem with this is that the body is continuously adapting to the work it does. The same routine done over and over again with no progression over time becomes less and less of a stimulus as your body adapts to the work. This familiarity can be useful when trying to prevent soreness while trying to peak, but isn’t a recipe for long term success.
The Finish Line
Strength is a widely misunderstood quality when it comes to improving distance running performance. Dogmatic ideologies regarding a poorly understood activity tend to fuel decision making by coaches and athletes.
The truth is that running might be enough for most of an athlete’s career. There is inherent risk in lifting weights, and while I would argue proper teaching lowers this risk, it may not be the best option for every athlete in every setting. Many schools don’t start lifting until the competitive cross country season has begun. For high school and college cross country athletes, in-season is typically not the best time to begin to learn these novel movements.
But for those looking for ways to elevate their training and performance while preventing injuries from sidelining their season, properly implemented strength training can become a critical tool in the training arsenal.