You may know that muscles are made up of different types of fibers. For memory: first of all, slow muscle fibers are distinguished, containing a large number of blood vessels and mitochondria, whose maximum return occurs during repetitive or prolonged contractions at an intensity below maximum. Then there are fast fibers pierced with nerves, the effectiveness of which is expressed in intense contractions with short and maximum efforts. The latter are divided into two subcategories – fast fatigue fibers and fast fatigue-resistant fibers. The entire physiology of effort underlies these contraction mechanisms.And the achievement of physical results from a motor point of view consists precisely of the constant repetition of contractions. And this requires a system for converting “fuel” into energy.
Depending on the intensity and duration of efforts, energy production occurs either without the participation of oxygen or with its participation. The breakdown of glucose, which is the main fuel during exercise, continues as long as the load itself lasts, and its intensity is low enough that more and more oxygen is required. Often they talk about anaerobic (without oxygen) or aerobic (with oxygen) glycolysis, but still we are talking more about a continuum, the dominant of which depends on the type of effort. The human body is essentially a hybrid motor driven by many energy systems, and the prevalence of one or another depends on the load.
The interesting thing about CrossFit is that the load fluctuates between the aerobic and anaerobic systems, acting through the addition of intensity throughout the workout.
And it is in this specific context that we most often hear about lactates.
Energy – and faster
As the intensity of the exercise increases and intense muscle contractions are repeated, the fast fibers produce large amounts of lactic acid ( lactates ). “Stored” form of glucose – glycogen- decomposes, releasing pyruvate (a salt of pyruvic acid, which then allows the production of energy). Pyruvate can subsequently enter the mitochondria, where, when exposed to oxygen, it is directly converted to energy (aerobic pathway). But when the intensity increases, fast fibers are no longer enough, the production of pyruvate begins to exceed their ability to be processed into mitochondria, and pyruvate accumulates at its entrance, turning into lactic acid (anaerobic pathway). This is also the case in the cross-training training scheme. The intensity here is high enough for both systems to function together: the accelerated breakdown of glucose, necessary for energy production during intense muscle contractions, leads to a significant release of pyruvate. At that moment,
The importance of lactic acid formation
The efficiency of the process of converting glucose to energy relies in part on the ability of the system to release glucose through the transfer of its protons H +. It is the formation of lactate that allows the release of proton carriers from their supply and quickly resume the operation. Thus, the formation of lactic acid allows the rate of glucose breakdown to be maintained. This partly explains why the more lactic acid is produced, the more intense work we are capable of.
Extensive ability and ability to reproduce
Schoffen and Aubert in 2007 put forward an important concept – the concept of the ability to reproduce. Up to this point, energy systems were considered as a machine producing, on the one hand, power (the maximum intensity produced during the effort in a given system), and on the other hand, productivity (the time of depletion of the used system and its gradual abandonment in favor of the power of the next system ). It is this second point that the authors call “extensive ability. ” They contrast it with the ability to reproduce high-intensity efforts within the same system. Therefore, we talk about strength endurance as the main specific need for cross-training.
Lactates at the heart of energy production in cross-training
As we explained earlier, lactic acid is mainly produced by fast fibers, whose mitochondrial saturation accelerates the production of pyruvate during intense exertion. This is particularly what happens during intense cross-training training cycles, which thus generate large amounts of lactate.
In this case, lactic acid is captured by nearby slow fibers, which, thanks to the aerobic system, will use it as an energy substrate. The remainder of the lactic acid produced is released into the bloodstream to be consumed by the heart (or other slow fibers made available again during active recovery) as a source of energy. That is why the cross-training technique during its TD uses predominantly active forms of recovery.
On the “one-shot approach”
In the 2010s, the debate over the “one-shot” exercise versus the “multiple-set” debate intensified. Some researchers and trainers – apparently in search of sensations – have actively discussed the seductive idea that one set, performed “to failure” (the moment you can no longer continue the exercise) is only slightly less effective than several and that this the gap does not justify the use of multiple approaches (proponents of the “single approach” report only a 3% improvement in results with multiple approaches).
These theories have echoed in cross-training, where long-term “burn-out” sets and short workouts are especially popular.
And while much of the research since then has found this paradigm flawed, here are some arguments to finally convince you that four is better than one.
- Who wouldn’t give up a 3% improvement in their results?
- The increase in muscle mass occurs in tired fibers due to the maximum muscle tension. However, the reasons for muscle saturation are different, and the only exercise approach can be stopped for other reasons than complete local muscle saturation (CNS fatigue, psychological fatigue, blood acidity, depletion of energy reserves and especially lack of technical skill). In other words, the “to failure” approach, showing good efficiency, cannot be used in an exceptional manner. In order for it to work, it must be combined with other methods. Peak loads should be replicated from set to set whenever possible, illustrating the concept of “multiple single set” or “repeatable single set” for the cross-training methodology.
Recovery time in CrossFit
The peak of lactic acid accumulation that follows a very intense set occurs approximately 7 minutes after exercise. After 60 minutes (and not after 24 or 48 hours, as they sometimes write about it), this level returns to normal. Therefore, it is quite possible to do two intensive workouts of the day (TD) on the same day or two days in a row. The problem may arise, rather, due to the gradual, day after day, accumulation of nerve and metabolic stress. Therefore, we recommend arranging 1 day of unloading every 3 days.
On the other hand, the active reduction to 40-50% of VO 2 max ( maximum amount of oxygen consumption during exercise -. Approx, wound) greatly accelerates the release of lactate (and therefore protons) in the blood. Therefore, we will systematically offer an active recovery phase of the same intensity immediately after each intense and prolonged effort.
On the other hand, Spencer and his team in 2006 found that after very intense, up to maximum, and very short loads for the resynthesis of phosphocreatine, passive recovery is most effective. Therefore, for strength exercises or high-speed running of high intensity, this type of recovery is preferably used in our method.
Finally, note that repetition of maximal efforts for less than 10 seconds, drawing strength from muscle energy reserves (phosphocreatine), can damage the exercise as a whole (decrease in intensity, loss of technicality, stop training). Therefore, this technique will not include any such load.
Sometimes lactic acid is spoken of as a limitation of athletic performance. But as we already know, lactates are a valuable source of energy. The real culprit of muscle acidosis is a proton released during the breakdown of glucose and leaving the cell simultaneously with lactate. Lactate thus fights against intermolecular acidosis and provides energy at the same time!
One of the features of cross-training at the start of working with large groups is the collective prescription of the load. In such cases, the TD offers the same number of repetitions for all and a certain barbell weight (if necessary, differentiated for men and women, as well as for competitors). At the same time, it is obvious that the muscle profiles of the members of the group are different even within the same sex or the same level. So, some athletes easily get 70% of their maximum and up to 15 repetitions in a row, while others, with a possibly higher maximum, can “break” at 10 repetitions.
Another parameter is technique. Due to it, some athletes spend their energy more economically than others, so their workload needs to be regulated so that they progress on a par with debutants. The last thing to consider is bodyweight, which significantly affects the level of maximum strength, and also increases the load in some exercises. So, the severity of squats with a barbell of 100 kg is not only the weight set on the barbell. To this should be added the weight of the practitioner himself, which sometimes equals doubling the weight. It becomes apparent that the load for an athlete weighing 60 kg and for one who weighs 120 cannot be set in the same way. This applies even more to pull-ups. Let’s take the example of a 90 kg beginner: he should start his training with an extra maximum load!
In practice, all this means that if you offer a TD group that includes 10 repetitions of squats from 100 kg and immediately after them 20 pull-ups – and as many times as possible in 5 minutes, then this workout will be different for everyone.
This is why the cross-training technique offers more adaptive alternatives:
- We will often talk about “the maximum (max) for X repeats”. It’s just about the maximum load you can handle X times. Example: The max for 5 is a load that you can handle 5 times, failing at the 6th.
- Sometimes we will not specify the load, leaving the choice of the most acceptable option to you, so that you can finish the TD. Do not hesitate to adjust the load during the session to suit yourself – if it is too difficult or too light.
- Of course, the technical adjustments and exercise options that are offered within the
- ccepted framework of cross-training remain a powerful tool for individual load planning. Therefore, there can be no question of abandoning this approach.
How to develop buffer capacity
Meanwhile, there is no end in sight of lactates’ bad reputation. We hear about lactic acid too often – despite the fact that the given levels of acidity in the human body are simply impossible (they speak of lactic acid at ph 3.5, while the level of acidity in the human body is about ph 6.5). The confusion, in particular, arises from acidosis, which regulates adaptability to intense physical activity. On the one hand, lactates facilitate adaptation – in particular, protein synthesis, and on the other – protons contribute to an increase in the acidity of the environment and the warming of proteins.
The key to neutralizing this antagonistic effect is to develop the body’s buffering capacity to neutralize protons. A variety of teams of scientists have been looking for the most effective protocols for this purpose.
It was found that the change in the buffering capacity of the muscles is clearly manifested after interval training in the form of sets of 2 minutes at an intensity in the range between 80 and 90% VO2max, with a one-minute rest-pause between sets.
During cycles aimed at improving this potential, this type of training is offered by our methodology.
Calculation of the load using the tempo
Working hard on muscle mass doesn’t have to be heavy lifting. For example, focusing on a technically accurate position will instantly improve a beginner’s performance. But as the athlete progresses forward, you can also use the concept of “energized time”, which is measured by the pace given to the movement. Measuring the length of each phase of the barbell squat itself is a very powerful way to increase the effectiveness of an exercise without adding weight or endlessly increasing the number of sets.
Take this example: imagine there are four “phases” in lifting a barbell, and each of them is measured in seconds. The first phase is in a standing position on straight legs, the second phase is bending the legs, the third is squatting (at different heights, depending on the type of barbell lift), and the last phase is straightening the legs. Depending on the number of seconds you spend in each of these phases, the same barbell weight will not be the same workload at all. To be convinced of this, it is enough to try squats with a barbell without any rhythm, and then, without changing the weight on the bar, repeat the exercise, maintaining 3 seconds in low positions and 1 second in an upright position. You may want to adjust the number of repetitions down.