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Foundations of Getting Faster

The Overload Principle and Training Intensity

In the last issue of Holeshot Magazine we introduced periodized training and the ten rules of training that make up its central philosophy. In this issue we will describe another brick in the foundation of periodized training: the overload principle.

Motocross training may consist of riding laps, lifting weights, running, mountain biking and other exericse activities. All these components that could make up your program must all follow the same scientific principles in order to continually improve your racing. Broken down into the simplest terms, training pretty much looks like this:

The overload principle

Apply stress to body –> break down body systems –> accumulate fatigue –> recover from fatigue –> supercompensate –> apply higher levels of stress to body –> repeat cycle until reaching peak of fitness
The stress you apply to your body during training is called workload. Workload is composed of the following elements:
  1. Frequency: how often you work out. The correct frequency depends on both ability level and where you are in the training year. A beginner may ride at the track twice per week and an expert may be able to ride at the track four times per week. In both cases, the frequency is correct for that particular racer. Frequency goes up as the training year progresses to increase total workload but goes down before a big race to allow proper recovery.
  2. Duration: how long you workout. This varies by day of the week, by time of the training year, and by ability level. Early in the training year, you may want to ride trails at a low intensity but for a long duration to stress riding endurance. At other times of the year closer to your peak you may want to ride 3 laps at faster than race pace which is very short duration in comparison. All this depends on what specific area of fitness you are working on that day.
  3. Intensity: The most important element of workload to hit correctly. Simply stated, this is how hard you go. On the motorcycle this is measured through a system called Rating of Perceived Exertion. During cardiovascular activity it is measured by heart rate. In the gym it is measured by the weight you are lifting. Intensity is the element that can cause the most positive change when administered correctly but can also cause the most damage to your season should you have an intensity overdose. You can have the correct frequency, the exact right duration, but if you blow intensity it won’t matter. Caution, peligroso, danger, etc.!

A successful motocross training program consists of:

Planned cycles of the overload principle where the three elements of workload are progressively changed to produce an increasing fitness level leading to a season peak.

Training Intensity

As stated above, the most powerful factor of the overload principle is intensity . . . but it is also the most dangerous. A dosage of the proper amount of intensity at the correct time will produce drastic gains in performance. A touch of too much intensity or intensity at the wrong moment in a training program can send you into the downward spiral of overtraining or at the very least cause you to suffer horribly at the next race. Intensity is like a drug….proper dosage at the proper time gives you excellent benefits while overdosing or mistiming of the dosage can literally make you ill.

Remember the first rule of motocross training: train moderately!! This is to ensure that you can go really hard on your hard days because you are actually going easy on your easy days. The most common error that athletes make in training is that they go too hard on the easy days turning the hard days into mediocre days at best. Quantifying intensity is the only way you can consistently use the correct intensity of training so you can make expected performance gains by making those hard days really count.

Intensity and Body Fuels

Measurement of training intensity is really a estimation of ratio of fuels your body is using to perform at that moment. There are two fuels that your body uses for energy production: Fats (FAT) and Carbohydrate (CHO). Similar to the air/fuel mixture your engine uses, FAT and CHO are used as a mixture in various ratios depending on how hard you are going. These two fuels are used by your muscles to produce something called adenosine triphosphate (ATP) which is the actual energy providing molecule your body needs to perform work. ATP is the energy “currency” that can be used by all cells in your body. The food you eat and the air you breathe eventually needs to be converted to this universally accepted energy currency.

At lower levels of exertion your body can produce ATP via aerobic metabolism. Aerobic means “with oxygen” and this combined with a fuel mixture of mostly FAT and less CHO produces ATP for your working muscles with no harmful by-products. As your intensity increases the proportion of CHO in your fuel mixture increases while the proportion of FAT decreases. The faster you ride, the more “rich” your mixture becomes with CHO and “leans” out on the FAT proportion. One goal of a training program is to increase the efficiency at which you produce ATP via mostly FAT metabolism and increase the intensity at which you can continue to ride using this metabolism and push back the level at which you start to need a more CHO rich fuel mixture. This allows you to perform using the fuel that has more storage capacity and does not produce a harmful by-product.

When you reach a very high level of intensity your body switches from aerobic metabolism to anaerobic metabolism. Anaerobic means “without oxygen” and at this high level of exertion your body’s need for ATP surpasses its ability to produce it with only oxygen. Your fuel mixture is heavily biased towards CHO and very little FAT is being used to produce the ATP. This anaerobic metabolism produces a negative by-product called lactic acid which is dumped into the muscles and produces the burning sensation and heaviness which if not counteracted will eventually cause you to drastically slow down or stop. When the lactic acid leaves your muscle cells and enters your bloodstream it loses a hydrogen molecule to become lactate. A major goal of a training program is to increase the efficiency at which your body can remove the lactic acid from your muscles and neutralize the lactate in your bloodstream.

The measurement of training intensity must be consistent from day to day in order to be useful. This means the smart MX’er must practice measuring intensity daily and be honest with him/herself during the measurement process. Intensity Iof training will be measured through the Borg rating of perceived exertion.

Rating of Perceived Exertion or RPE

The Borg rating of perceived exertion has been in use in sports testing venues all over the world for a very long time. It is a simple method of self rating the intensity of exercise you are doing. Although subjective, it is the most practical option in motocross for measuring training intensity as there are too many uncontrollable variables that make other methods of measurement inconsistent: track prep, temperature, etc. Elite athletes become very adept and consistent when using this scale to self report training intensity and you can too. Practicing the use of the Borg RPE scale will allow quick measurements at any riding area in any condition.

The scale looks like this:

To help equate these zones, here are some more familiar comparisons specific to MX:
  • RPE 17 would be what you would ride if you were told to ride a 20 minute moto with equal lap times every lap.
  • Trail riding for 2 hours at the same pace with friends for fun would fall somewhere in the RPE range of 9-11.
  • A one hour hare scrambles event would clock in at RPE 14-16. • A two minute all out sprint to catch the rider ahead of you for the moto win would be RPE 19-20.

With constant use of the RPE scale it becomes very consistent and accurate for you as an individual rider and it will prove to be in invaluable tool in helping you control the most important aspect of training load.

You are now armed with yet more tools to sharpen your training regimen. The concepts introduced in the last few issues of Holeshot are not easy to learn or understand and even harder to put into practice. Just keep in mind that with a little effort now to create a solid base of training knowledge all your future training will have purpose and goals behind it which will pay off in race results for the rest of your career. Use your mind as much as you use your body and there is no telling how far you will go in your MX career!

– Originally Published in Holeshot Magazine 


Andrew Short

#29 | Pro SX/MX

Justin Boyd

#91 | Amatuer MX
mt. carrol area pic

Jamison Duclos

#23 | Amateur MX