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  • Writer's pictureDavid Wadsworth

Dial up Intensity Using Training Zones

Updated: Oct 12, 2023

Training zones are a crucial tool for athletes and coaches in planning and executing effective training programs. They provide a structured framework for categorising and controlling the intensity of training sessions, helping athletes optimise their workouts and achieve specific fitness goals. Here's why training zones are important and how to choose the right one for you:

1. Precise Intensity Control

Training zones offer a precise way to measure and control exercise intensity. Instead of vague terms like "hard" and "easy", athletes can use quantifiable metrics like heart rate, power or perceived exertion to determine how hard they work during a session. This precision is essential for achieving specific training objectives.

2. Individualisation

Different athletes have different fitness levels and goals. Training zones can be tailored to an individual's capabilities and objectives. Foe example, a seasoned cyclist aiming to improve endurance may have different training zones than a beginner looking to build aerobic capacity.

3. Aligning Training Sessions with Goals

Training zones should be designed to align with various training goals, such as improving endurance, fatigue resistance, increasing speed, or building strength. By working within the appropriate zones, athletes can focus their efforts on the aspect that matters most to them.

4. Monitoring Progress:

Tracking training data within specific zones allows coaches and athletes monitor progress over time. This data-driven approach helps identify improvements in performance and areas that need attention, facilitating adjustments to training plans.

5. Injury / Illness Prevention:

Training within the correct zones minimises the risk of overtraining, which can lead to injuries, illness and burnout. By balancing hard and easy sessions and adjusting zones as fitness improves, athletes can maintain a sustainable training program.

At a fundamental level training zones are a communication tool that allow a coach and their athlete to understand each other when communicating about today’s training session.

How “hard” should the athlete go when a hard effort is prescribed? How “easy” should the easy effort be? Training zones help with intensity: how hard do you need to train today. For athletes to improve, they need to work at certain intensity levels for periods of time, so setting up appropriate intensity zones is crucial. Many self-coached athletes tend to work at moderate intensities most of the time, hindering their progress.

Choosing the Right Training Zone System

The choice of training zone system depends on multiple factors, including the athletes sport, training goals, fitness level, and available monitoring tools. Here are some common training zone systems:

1. Rate of Perceived Exertion (RPE):

RPE-based zones rely on an athletes subjective perception of effort. This system is useful for all athletes to learn to what hard, moderate and easy actually feel like if they have a quantitative metric like power or heart rate to compare against. It is useful for those athletes who don't have access to heart rate monitors and power meters. RPE scales, like the Borg scale, provide a framework for rating perceived exertion on a scale from 1 to 10.

2. Heart Rate Zones:

Heart rate (HR)-based training zones are widely used and accessible to most athletes. They categorise intensity based on a percentage of the individual's maximum heart rate (e.g. zones like Zone 1 for easy recovery, Zone 5 for maximum effort). These zones can be determined through field testing or lab measurements.

3. Power Zones:

In the modern era cyclists use power meters to measure wattage output during their rides. Power-based training zones can be calculated in multiple ways, the most common (but not necessarily the best ) method being based on a percentage of the athletes' Functional Threshold Power (FTP). These zones offer greater precision specific to cycling.

4. Lactate Threshold Zones:

A graded exercise test in which lactate levels are measured (along with heart rate and power) identifies the two key physiological points at which lactate levels begin to rise. Training zones based on an lactate thresholds are highly individualised and provide afford a more sophisticated approach for endurance athletes.

5. Speed or Pace Zones:

Runners and swimmers often use pace zones (since power is not available for these sports), especially when preparing for races. These zones are determined by an athletes race goals and current fitness levels. Pace may be used in track cycling (lap times for pursuit training).

What Training Zone System is Best for Me?

Training zones are created with the aim of matching exercise intensity to the corresponding internal physiological changes. The aim is to train at the correct intensity level to stimulate the desired physiological response. The choice of training zone system for a given training sessions thus depends on your specific training goals and the physiological responses you need to stimulate.

It also depends on what methods of measuring intensity you have available to you on your bike.

If you can't measure the metric whilst training then you can't use that measure to define intensity.

Some metrics are better for monitoring particular intensity levels than others. For example, heart rate works well for a low-intensity ride, but isn't ideal for high-intensity efforts.

The 3-Zone Physiological Model

Consider the 3-zone physiological model as a valuable starting point for understanding training zones. This model requires a lab test in which heart rate, lactate levels and power are measured to identify key physiological changes accurately.

An example of the 3-zone model is shown in the diagram below.

Heart Rate & Blood Lactate Concentration Vary with Exercise Intensity (Power level)

The key measurable physiological events are marked by lines and are known as the "first and second lactate turn points" (or "aerobic and anaerobic thresholds"). The second turn point is what many endurance athletes know as their "threshold" or what "FTP" is supposed to estimate.

The reason the 3-zone model is attractive is that your individual heart rate, lactate & power levels are measured accurately and are used to identify the key changes in your internal physiology.

As you can see above, heart rate (which mirrors oxygen consumption) rises linearly with exercise intensity (power). Lactate (and acid levels) increase in a very different manner - initially lactate levels don't change much but at a certain point (the second lactate turn point) they start to rise very quickly.

In other words the harder you push on the pedals, the faster your heart beats to pump blood (oxygen) to your muscles and the more lactate (and acid) your working muscles produce. Eventually you push so hard that you produce so much lactate (and acid) that it inhibits your muscles from contracting as hard, and you are forced to slow down or stop.

Once the 3-zones are accurately defined, coaches and athletes can begin to use this information to inform their training programs.

The 3-Zone Model in Training

Zone 1 (Green): Low intensity, suitable for recovery or long rides (>3hrs).

Zone 2 (Yellow): Moderate intensity, used for shorter endurance rides or longer aerobic intervals (10-60mins).

Zone 3 (Red): High intensity, unsustainable for long periods due to rising blood lactate and fatigue. Typically used for interval training.

When do you need more than three zones?

The 3-zone model can cover a broad intensity range. Further subdividing the three zones can be beneficial for specific training sessions, especially when focussing on high-intensity “red zone” training. The number of zones you need depends on the metrics you can measure during your workouts. Using a formula to estimate zones may lead to inaccuracies.

For more competitive athletes, power is essential.

The opportunities to progress in training and racing using a power meter are greater, and its relative affordability has seen all serious (and many not so serious!) cyclists use it daily. It is a metric well suited to high-intensity training as you can see whether you are in the correct zone from the first pedal stroke.

Establishing training zones is an integral part of training to improve. Exactly what system you use will depend on your goals, physiology and the equipment you have available. Then it’s down to some hard work out on your bike!


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