The exercise physiology term that describes the phase of training where the athlete’s goal is to gain larger muscles is “hypertrophy.” Hypertrophy programs are also commonly referred to as body building programs as the goal is to “build the body.” This would seem applicable to contact sports like football and rugby (a whole other argument is if it actually is applicable). However, it is a common goal among CrossFitters to gain muscle mass since it will help them compete with the heavier weights. This post will look at a few of the scientific arguments on the costs and benefits of gaining muscle mass. A follow up post will examine more of the observational and experience related arguments of the same topic.
Part 1: Bigger Muscles = Stronger
This is a fact. If you increase the size of your muscles, you will get stronger. If you compare your body to many of the top CrossFit athletes and you are slimmer built than all of them, then gaining mass would seem to be the best bet, as there is a reason all the top athletes are bigger than you. However, there are exceptions to the rule like Josh Bridges and Chris Spealler. Keep these exceptions in mind.
Part 2: Bigger Muscles = More Oxygen
This is also a fact. If you have more muscles that require more oxygen to be transported via the bloodstream, it means that your heart needs to increase the amount of blood it can pump to your body by either increasing the heart rate or increasing stroke volume. Increasing stroke volume is the preferred choice and having a larger stroke volume decreases your resting heart rate, which then gives you more “space” for your heart rate to increase throughout exercise.
Part 3: Strength Training diminishes the efficiency of the heart
The training which causes hypertrophy (with some exceptions) does not cause increases in stroke volume, it actually causes decreases in stroke volume due to the hypertrophy of your cardiac wall due to the back pressure of blood against the heart (specifically left ventricle). Basically, having larger muscles (and sometimes the training to have larger muscles) will put more strain on your heart, especially during your WOD. The result of this strain is thicker heart muscles which leads to decreases in cardiac performance. (For further information, see Baggish et al, 2008, J Appl Physiol).
Part 4: Scientific Comparison: Increased Strength minus Oxygen Demands = Better Performance?
So now we have to make a comparison of the scientific aspect: Are the benefits from gaining muscle mass able to outweigh the negatives of increased oxygen demand and potential decreased cardiac output? Will the positive impact on force production be able to outweigh the negative impacts of performance? – “it is only useful to get bigger if the force that comes along with the size is greater than or equal to the amount of force it takes to move you at maximal speed and efficiency.” (Dr. Brian Biagioli).
Simply put, if your bigger muscles make you less efficient in your movement to the point where each individual lift costs more energy than it did before, your new muscle mass is holding you back. However, if you are still able to move with good efficiency and the increased strain on the heart is negated by the decreased amount of “strength energy” used by each lift, your new muscle mass has improved you. Is this easy to figure out? No. It takes an athlete and/or coach that is very in-tune with the body in question, which in turn necessitates tailored programming when coaching competitive athletes.
Part 5: Beyond Bigger Muscles – Muscle Architecture
There are other improvements that the body can make in response to various training stimulus beyond hypertrophy. These improvements occur on a cellular level and involve the various components of nervous and muscular systems. For example, training specific to strength / power training will produce changes in the variants of troponin I, troponin C, troponin T, tropomyosin and alpha-Actinin in the actin filaments. Similar changes to the myomesin on the myosin filament will occur as well. Other important changes associated with the muscle architecture include increases in parvalbumin, adeylokinase, and an important one: improvements in branching at the neuromuscular junction which yields increased calcium release and faster contraction. The list goes on, strength training will improve the speed of calcium channels at the triad, improving cycle time, increases in speed of the sodium / potassium pumps and decreases the size of the terminal cistern – basically allowing the muscle to not only contract faster but do it again faster thus applying more force at a higher rate – increasing the overall muscle’s ability to improve efficiency.
Part 6: How do we obtain these improvements?
Specific improvements are correlated with specific training stimulus just like hypertrophy is correlated most to increased time under tension with minimal rest periods at loads between 70 and 85%. Most of the improvements listed in Part 5 can be accomplished by lifting really heavy weights or moderate weights at very fast speeds. Basically, to yield the most of the muscle architecture improvements, perform “strength" lifts that are heavier than 80% and up to about 100% (squats, presses, pulls) and Olympic lifts that are both heavy and hard (80%+) and lighter and faster to optimize speed (30-70% depending on individual technique). Also include explosive movements like short sprints, high box jumps, depth jumps and single leg jumps as well as upper body plyometrics and ballistic exercises (e.g. clap push-ups, med ball throws).
Part 7: What about endurance and if I am in the category that actually needs bigger muscles?
Remember our examples earlier? Chris Spealler and Josh Bridges are both light, fast and strong (around 150lbs) with maximal lifts that pale in comparison to the average CrossFit games competitor. However, both have finished on the podium at the CrossFit Games. These two guys are physical and physiological specimens who are capable of sustaining a high level of power output in comparison to maximal strength over an extended period of time. These two athletes most likely have a higher capacity of delivering oxygen to the muscles, which aids in repeated muscle power output. Simply put, these two athletes have maximized efficiency by having large aerobic capacity, anaerobic capacity and strength endurance, while maintaining only the necessary amount of anaerobic strength power to compete at high levels.
The necessary amount of anaerobic strength power is an important concept when planning your muscle mass goals. What is the minimal amount of mass needed to hold up against heavy CrossFit loads? How do we train to have all of the above traits optimized? This discussion will continue next time on part 2…
That was A LOT! Hope you stuck with me through that one, there’s more to come! As always, any questions or comments, share below and I’ll follow up immediately.