The Big 3 - Frequency, Duration, and Intensity

Training Load Variables

Have you ever wondered what people mean when they say “I’ve been training a lot?” What does that mean exactly? What determines a training load, really? It’s simpler than you think.


1. Frequency

Frequency means how often you train. Typically people quantify how often they train with their week as the time frame e.g. “I have time for 4 workouts a week.”

Frequency doesn’t get a lot of attention when people talk about training load, but it is important because of how your body reacts to training stress. Lots of athletes get in the habit of the ‘weekend warrior’ syndrome where they have a light week where they miss lots of workouts and they try to ‘make it up’ on the weekend. That habit rarely works well for improving their fitness.

Your body isn’t a machine. Every day you have a certain amount of stress you can positively adapt to. Piling on workouts in a short amount of time overwhelms your body’s ability to adapt. It’s deceptive, but two athletes could do the exact same amount of workload each week but the distribution of that workload determines if the adaptation is positive or negative.

For reliable, consistent positive adaptation to workload, you have to break up your workload into manageable, spaced workouts so your body has enough time to adapt – that’s the power of frequency.

2. Duration

Duration means how long a workout is. It’s also frequently used to capture how hard someone has been training over a week over a month by saying simply “I trained 10 hours this week, or I trained 40 hours last month.”

The physiological stress of a workout depends partly on how long you’re subjecting your body to a given intensity. Note here that intensity and duration are inversely related e.g. the longer you train, the lower intensity you can maintain (and vice versa).

Duration doesn’t get as much respect these days as it used to, but make no mistake, it matters. Snake oil salesman like to pretend you can simply swap out intensity with duration as a ‘cheat’ code to fitness but to really get fit there’s no shortcut to simply riding your bike a lot. 

The reason you can’t hack your way out of performing long workouts on the bike is long aerobic rides do put as much stress on your autonomic nervous system as high-intensity rides do. Long term, you can build more aerobic fitness with less recovery.

3. Intensity

Intensity means how hard your workout is in relation to a physiological or subjective anchor point.

Common anchor points:

  1. Maximum heart rate
  2. Threshold Heart rate
  3. Functional Threshold Power
  4. Lactate 

Whichever anchor point you choose, the point of choosing an anchor point is so you can measure:

  1. How hard you should go during a workout.
  2. How hard you went (important for performance analysis and planning)

Intensity execution determines race performance (assuming workout frequency and duration are sufficient). 

Performing workouts with intensity that closely mimick race demands at the correct time is a crucial determinant of success. 

That said, intensity is dangerous because it places high physiological stress on the body and stimulates the autonomic nervous system. For this reason, intensity needs to be carefully monitored and prescribed to work well otherwise the risk of burnout, illness, or injury rapidly increases.

But wait there's more!


Dose refers to how hard a workout is relative to your ability. How can you make a workout hard?

You manipulate either the duration (go longer) or intensity (go harder) or both (are you serious? Yes.)

Really smart people have invented a way to quantify how hard a dose is in relative terms by combining intensity and duration to produce a nifty little term called Training Stress Score, or TSS – maybe you’ve heard of it?

TSS demands its own article, but for now it’s more important to know it exists than to explore the concept.  


Density means how closely spaced your workouts are.

High density indicates that you’re executing high-dose (hard) workouts close together. e.g. intervals on back to back days or only spaced by one day.

Low-density training spaces out high dose workouts with several low-dose days. e.g. 3 easy days between high-dose workouts.

Examine the image to the left. The top week and the bottom weeks have identical workouts, but their density is dramatically different. 

The top week has a greater density than the bottom week. In the top week, Tuesday and Wednesday have hard workouts in the morning with afternoon endurance rides culminating in another hard day on Thursday.  That’s 5 workouts, 3 of them intense, in 3 days.

The bottom week has the same 5 workouts as the top week, but spaced out over 5 days. 

Even though the weeks have the same workouts, the training effect and execution difficulty between the top week and the bottom week are so different that they may as well be different weeks.  

So there you have it:

Training load is a combination of frequency, duration and volume. 

While the three training load variables are straightforward in and of themselves, the manipulation of these variables is a massive space bound by physiology, explored by science, and applied by art.  

So, what's the right training load for me

That's literally why coaching was invented.

The quickest answer is this:

Determining the optimal training process that unlocks YOUR potential, however, is an iterative, individual process that takes years. 

If you want to find out, you know who to ask.