Training Load monitoring for triathletes

17 August 2018

Training load monitoring for triathletes is somewhat of an art form with the difficult task of managing athlete fatigue across multiple sports while trying to ensure adequate load is applied to result in performance gains.

In this blog we’re going to break down the different components of load tracking and how you can apply this to your own training. To open this blog let’s put aside the different sports and explore the basic concepts of training load.

At the core of training load in Today’s Plan is the T-score metric. This metric is calculated based on the duration of a workout multiplied by its intensity and will be assigned to all your swim, bike and run workouts so long as there is Power, Pace or HR data present. T-score will then be used to calculate your long term training stress (CTL), short term training stress (ATL) and then these metrics can provide you with your training stress balance in the form of TSB or TSB(r)%.

Now there are two reasons to monitor training load, firstly is to ensure that adequate training load is being applied that will trigger performance gains upon recovery. The second component to training load monitoring is managing fatigue and ensuring that we’re minimising the risk of illness or injury. To begin with let’s focus on ensuring we’re applying adequate training load.

Training Load and Performance

The primary metric we want to consider here is our Chronic Training Load (CTL). Without getting too specific on its calculation, CTL is basically looking at the long term application of training stress. If you’re consistent in your training and steadily increase your overall duration and/or intensity, your CTL will rise. It is also commonly referred to as “fitness” which is a gross misrepresentation of what it actually tells us. Simply doing more or going harder is not going to guarantee fitness. It may do so, but it also may not. Terminology like this is also highly confusing when leading into a race. As you begin to taper and recover, your CTL will decline to allow for adaptation and to arrive at a race feeling fresh. Are we losing fitness at this time? Absolutely not! Now that we’ve cleared that up, lets move into the application of training load monitoring.

Let’s assume we’ve got our big A-race coming up, for argument’s sake let’s pretend I’m competing in the Ironman World Championships in Kona. We’re actively training and recording our swims, bikes and runs, each of which are being assigned a T-score. There are two common methods for monitoring these as a CTL that are employed by coaches and athletes. One option is to combine all of these values into a single CTL metric (Swim CTL + Bike CTL + Run CTL). There are a number of reasons why this method is not really going to provide much value.

A combined CTL provides no useful information on how the CTL was built. If I built to a CTL of 150 in preparation for my attempt at World Championship glory, have I applied adequate training load? The answer is, we don’t know. For all we know I just rode my bike the whole time and this is certainly not going to help out my swimming and running performance. This method also assumes that the methods to calculate the training stress are equal. It’s common sense to know that a 1-hour run and a 1-hour ride are not equal in the stress that we’re going to be subjected too. The mechanical loading from impact forces in running are going to make a big difference so that score assigned to an activity needs to be reflective of this.

In Today’s Plan we’ve addressed this by developing unique T-score algorithms for each sport that are designed to more closely reflect the load applied in each session based on the unique demands of each sport.

When tracking CTL as a triathlete it is always more useful to monitor this in a sport specific manner as it will give us really useable information about the balance of our training across the 3 sports. It will allow you to visualise when you’re specifically targeting the swim, bike or run and will let you understand what type of training loads have led to success in the past. Trying to make big improvements your swim, bike and run all at the same time is a really difficult task so it’s quite common for coaches to try and maintain your ability in one or two sports while focussing on the others with a targeted training block. The sport specific load chart will make it really easy to understand what’s occurring and also when you might need to reassess your focus if you find your training load in one sport is beginning to decline too greatly.

Sport specific Chronic training load monitoring

Training Load and Fatigue Management

The other key reason to monitor training load is fatigue and injury management. It’s also at this point that we need to consider how each sport can affect the others. From a performance perspective, if I go and complete an epic 6-hour bike ride then it’s not going to provide all that much crossover benefit to my swimming or running performances but it’s absolutely going to affect my ability to complete a hard swim or run the next day. The same goes for the other sports, if you complete a targeted running week and increase your mileage, its safe to assume that you’re going to need to reduce your training load in swimming and cycling. So while combining each of the sports to ensure we’re applying appropriate training load for performance makes little sense, there is absolutely an argument for combining these metrics to manage and monitor fatigue.

When looking at fatigue management with combined sports I like to use the TSB(r)% as my go-to as it provides a relative load ratio as opposed to absolute values which can be skewed by the total individual training load in each sport. As a rule of thumb, spending the majority of your time between 80-130% TSB(r) will ensure you’re not over or under training. If you’re starting to see values in the 150% range or higher then it may be a red-flag that you should take a day off or strip some of the intensity out of a session. Obviously if you have a coach then ensure that you take their lead in this regard as they’re most qualified and aware of your other life stressors that may be contributing to your central fatigue.

Setting a floor and ceiling on combined training load to manage fatigue and minimise injury risk


When reviewing your training load its important to remember that these values are entirely unique to you. The training load floors and ceilings above are rough guides that should be tweaked based on your own subjective feelings. If you’ve got a coach then they will be most qualified to set these limits for you. When looking to monitor your training load using these methods don’t be afraid to reach out to our team of coaches on our Support line for advice.