Performing and analysing torque intervals

We have recently launched a short course entitled, “Cycling Science: the essentials of cycling physiology and coaching”. For further information about the course, please click HERE. In this article, we are covering content from the fifth module of this short course, where we provide examples of our favourite training sessions.

Two weeks ago we discussed the concept of periodisation, and compared the traditional and block periodisation models. If you missed that article, please click here. Block periodisation recommends the inclusion of short specialised mesocycles (blocks), repeated continually throughout a training year. We recommend that athletes begin a 16 week macrocycle with the ‘General Preparation’ block or phase. The main objective of this mesocycle is to prepare the musculoskeletal system for the subsequent phases where volume and intensity are increased. The main goals of this training phase are increases in functional strength and muscular endurance.

 

As previously discussed, each block should consist of key training sessions which target similar adaptations. During the ‘General Preparation’ phase, the key training sessions should consist of strength or torque intervals. Torque is the rotational force applied to the pedals during each pedal stroke. It is calculated by multiplying the force applied to the pedals, by the crank length (lever arm). Crank length will be constant, so torque is really an indicator of the force applied to the pedal. Torque is an important variable for cyclists to consider, because power is the product of torque and angular velocity (cadence). Should a cyclist improve the amount of torque they are able to produce at the same cadence, they should by definition, improve the power they are able to produce.

 

Strength or Torque intervals, also often referred to as over- or big-gear intervals, are simply performed through sustaining a high power output at a low cadence. We will now show explain how to perform a set of torque intervals, and demonstrate how to analyse one of these workouts.

 

Torque interval pedal stroke .jpg
Figure 1: Torque (Nm) is the product of the force (N) applied to the pedal, multiplied by the distance of the lever arm (m), which in this case is the crank length.

 

6 x 4 minutes of torque work


A key session to perform during the ‘General Preparation’ block is 6 x 4 minute torque or strength intervals. We will now break down how to perform this session.

 

Calibration

 

If you are using a power meter, we would strongly recommend that you perform a manual calibration before the start of your warm up, and possibly before the start of your first interval. The calibrations will increase the reliability of your measurements.

 

Warm up

 

Each training session should begin with a good warm up, and 30 minutes should be sufficient. If you are performing the session outdoors and it is particularly cold, you may want to increase the length of the warm up. Conversely, if you are performing the session indoors, a shorter warm up may be sufficient.

 

Intervals

 

These intervals are best performed on a steady, steep gradient (8-12%) where you can use a gear you are just able to turn over at a cadence of between 40 - 50 rpm. Focus should be on the complete pedal stroke, keeping your shoulders and hands relaxed during climbs while focusing on a stable pelvis.
Push the lap button at the start and end of each interval in order to mark the intervals. This will help you analyse your session once it is completed.

 

Cool down

 

Once you have completed the final interval, cool down in order to improve your recovery for subsequent sessions that may follow later in the week. Once again, a 30 minute cool down should be sufficient.

 

We recommend that you try and use the same hill/gradient for each interval, because this will provide you with consistent data to analyse. Figure 2 is an example of a torque session performed by one of our athletes. Each interval of the session was performed on the same climb which made the intervals a lot more consistent and analysing the session a lot easier.

 

8 x 4 minute torque session.png
Figure 2: An example of an 8 x 4 minute torque session

 

The outcome of this workout should be the amount of torque (Nm) produced in each interval, and not power output (W). Lowering the cadence (selecting a harder gear), increases the force that is applied to the pedals which will increase the torque (Nm) produced (Figure 3). The relationship between torque and power output will be different during these intervals compared to your usual high-cadence efforts. This is also illustrated in the warm up and cool down periods in Figure 3.

 

torque power during high cadence.png
Figure 3: The relationship between torque and power output. During periods of high cadence (warm up and cool down), where easier gears are used, torque is low compared to the low cadence (hard gear) intervals.

 

A great way to track your progression during the ‘General Preparation’ block is to analyse these sessions, and plot the torque values for each of the 4 minute intervals, add them all together and divide by the total number of intervals (6 or 8 depending on the session). This will provide you with the average for the set of intervals. The graph below shows how we plot an athlete’s progression during their block. The first two sessions went well, but the third session shows a decrease in the amount of torque produced. The drop in torque was most likely due to some acute fatigue, so we allowed for a slightly longer rest before the next session and they were able to produce their best numbers in the two subsequent sessions.

 

If you do not have the software to be able to calculate Torque, you may calculate crank torque by using the following equation:

 

crank torque formula calculation.png

 

 

Torque progression of an athlete.png

Figure 4: Torque progression of an athlete

 

If you do not have a power meter, focus on the cadence and gear selection. You will be able to track your improvements by being able to push a bigger gear at the same cadence for the same session.

 

As a reference, elite male cyclists are producing around 1.5 Nm/kg of body mass during a 4 minute torque interval session.






5 Comments

SwissVan, Jun 13 2018 09:18

Interesting, how high is the risk of knee injury doing these kind of low cadence strength training intervals?

SciencetoSport, Jun 14 2018 08:23

Interesting, how high is the risk of knee injury doing these kind of low cadence strength training intervals?

Thanks for the question SwissVan. It is an important one.

 

If you are not adequately conditioned (muscle weakness or poor coordination), your patellar might not track correctly and this could result in injury. 

 

If you experience any discomfort, we recommend you stop the session, and see a sports physician. 

Kobus47, Jun 15 2018 06:40

I've come across a number of riders who cruise around in a 53x11 for 4+ hours as part of their strength training. Is there any merit to doing this?

SciencetoSport, Jun 17 2018 11:11

I've come across a number of riders who cruise around in a 53x11 for 4+ hours as part of their strength training. Is there any merit to doing this?

Hi Kobus

Thank you for the question. 

As with any interval or effort, longer isn't always better.

The goal of these intervals is to accumulate a large amount of high force work.

Using shorter over-gear periods will allow you to generate more force, which will lead to a greater stimulus. 

We typically prescribe 4 and 10 minute intervals, but also recommend longer periods (~60 minutes) of torque work. 

4 hours or more might be too long and reduce the quality and effectiveness of the session. 

 

The same could be said for a high-intensity interval session. The goal of a high-intensity interval session is to accumulate work above threshold. You can only sustain a certain amount of work at intensities over the threshold. 

That is why high-intensity sessions are broken down into intervals, usually 5 minutes or less. A 4 hour high intensity effort would not be possible, because you cannot sustain those intensities for that long. 

 

So trying to ride in a big gear for a long period won't allow you to accumulate more work at high force. 

We would recommend that you stick to sets of torque intervals rather than one long ride. 

 

We hope this adequately answers your question,

Kobus47, Jun 19 2018 05:30

Hi Kobus

Thank you for the question. 

As with any interval or effort, longer isn't always better.

The goal of these intervals is to accumulate a large amount of high force work.

Using shorter over-gear periods will allow you to generate more force, which will lead to a greater stimulus. 

We typically prescribe 4 and 10 minute intervals, but also recommend longer periods (~60 minutes) of torque work. 

4 hours or more might be too long and reduce the quality and effectiveness of the session. 

 

The same could be said for a high-intensity interval session. The goal of a high-intensity interval session is to accumulate work above threshold. You can only sustain a certain amount of work at intensities over the threshold. 

That is why high-intensity sessions are broken down into intervals, usually 5 minutes or less. A 4 hour high intensity effort would not be possible, because you cannot sustain those intensities for that long. 

 

So trying to ride in a big gear for a long period won't allow you to accumulate more work at high force. 

We would recommend that you stick to sets of torque intervals rather than one long ride. 

 

We hope this adequately answers your question,

Thank you very much for the feedback and the article!