Track Cycling Concepts: Torque

What is torque, why it matters, and how to train it    

This blog is the first in a series which discusses key cycling physiological concepts and how they relate to effective training. A lot of this information can be found in sport science publications, which are not always easily accessible to the athletes; therefore, the series is written in a manner which is detailed, yet relatable, so that riders  can apply the concepts to their own training, knowing more about what they are doing - and why.  

We start by looking at the concept of torque. Follow up posts will look at other aspects of cycling forces, such as power (watts), RFD (rate of force development), strength training contributions, ‘training with intent,’ etc.

So what is torque?

Torque is the rotational equivalent of linear force, or ‘rotational force’, and is commonly seen in N.ms (Newton Meters). Most of us will associate torque with torque wrenches (like the ones used to tighten bike parts), but in bike racing it relates to the rotational force being generated by the leg, and being passed into the drive train.

We experience our best examples of torque when accelerating all-out from a slow speed, such as during a standing start. Using a standing start as the example: the highest torque values occur in the first few seconds of the acceleration, after which the torque values start dropping precipitously. The inflection point for this drop off is somewhere around 30-55rpm, though it will be different for everyone. You will see the importance of this when we discuss training approaches.

We want torque, but how do we develop it?

One of the important tenets of sprint training is to target the intended systems as specifically as possible in each session, without compromising the intensity or quality as the efforts progress. This means that doing too few efforts in a session will leave adaptations (and therefore trainable speed) on the table; while too many efforts will start to impact the wrong mechanisms and create fatigue which will impact the rest of the session - and possibly the rest of the week’s training.

This principle of staying within the target adaptation system range becomes particularly important when training for torque. We discussed that torque will start to drop off when an inflection point of around 30-55 rpm is reached. It follows that any effort after this drop-off point is time spent training outside of the intended adaptation, will add to the athlete’s fatigue, and in turn makes subsequent efforts less effective. This is why each effort should only last up until the torque drop-off point.  Practically, the easiest way to implement this is to use a predetermined distance of around 20-50m.  Best practice is to adjust the length of the efforts based on their powermeter readings (if there is a clear drop-off in torque before the end of the effort, shorten the efforts by 5metres and repeat).

Image source: Maximal muscular power: lessons from sprint cycling

 

*The point where the torque and power intercept, is the same point that we finish our torque development efforts (when the torque is on the high end and the power is on the low end).  Notice that the longer the effort goes on, the lower the torque value is, and the higher the power value is.  If we were to continue the effort into the peak power phase, we would be training power, and no longer peak-torque production.

The question everyone asks next is: but what gear do I use?!  I get this a lot, and I really dislike saying “it depends,” so I typically recommend “the biggest gear you have that does not distort your form or technique”. Some of the typical “distortions” that start to pop up when using a gear which is too big are: pulling too hard with the arms and oversteering the bike, staying too centered over the saddle and not getting out in-front of the bike, not extending the legs enough, aggressively throwing the head around all over the place, etc.

So what does a torque training session look like? A good session to start with would be 3x sets of 3x standing (or slow rolling) starts, for a distance of about 20-50m (or up to a cadence of about 30 - 55), in a BIG gear. Gear should be as big as you can go without form distortions, and could be upwards of 110” for some athletes, or up to somewhere in the range of ~160”+ for others. 

Video source: Phillip Hindes Standing Start

How does lifting fit into torque development on the bike?

Much of a sprinter's training takes place in the gym, so let’s look at basic torque development in the gym. We have discussed that peak torque is produced at 90º, which is why different lifting variations (such as box squats, deadlift partials and step-ups), which leverage that  90º hip and knee angle, are such great tools for cyclists.  

Let’s take a look at the box squat and how it uses those joint angles for maximum torque production.  The main benefits of the box sprint to a sprint cyclist are A) eliminating the stretch-shortening reflex, to create a dead-stop concentric lift; and b) the peak-torque/90º joint angles.   To execute a box squat, the athlete loads the bar on shoulders, lowers to sit on a box, unloads the legs temporarily, then re-engages and stands up, generating maximum torque right off the box.   Generally a box that puts hips slightly above the knees will put the knee and hip at about the right 90º angle (depending on the athlete’s morphology). Similar to the recommended big-gear start session, best practice is box squat sets that emphasize quality without unnecessary fatigue: e.g. 6-8 sets of 2 reps, or 4-6 sets of 3 reps (loaded to about 85%+ of 1rep max).

Image source: a frame from How to do a box squat.

*We can see the athlete with just slightly less than 90º angles at hip and knee in this box squat, which is an ideal environment for building torque for a cyclist.

Negative torque

One of the buzzword/concepts that floats around (but maybe isn’t quite understood) is ‘negative torque.’  Negative torque is simply torque which is applied in the opposite direction to the one driving the bike forward (aka, backpedal pressure); this is similar to the engine braking effect experienced in cars. Negative torque in cycling is a phenomenon that we often see with CNS (central nervous system) fatigue, at higher cadences and longer efforts.  Essentially, at longer distance higher cadence efforts, the brain has trouble deactivating the leg that just finished the power stroke and is now quickly on the back of the crank. If this leg still has some engagement, there will be a resistant pressure on the opposing side of the crank, which inhibits the new front leg’s driving force (aka, “pedaling squares”). This opposing force is negative torque, and can be quantified with some power meters using some form of pedaling dynamics or torque effectiveness devices.  

While there are some training interventions that are used to mitigate this CNS fatigue (such as longer, high-rpm efforts), we have also found that different athletes will have different natural negative torque inflection points, which helps to personalize gear selection. The goal for a sprinter is to have only positive torque for the entire effort. If we have an athlete that has a faster standing lap on say a 94” gear, but then exhibits negative torque for the entire second lap of a 500m TT, then we might gear up to the point where the athlete can hold positive torque for the entire TT.  This will slow down the opening lap, but will avoid the opposing forces of the “negative torque” towards the end of the TT, and can result in an overall faster event time.   

This is highly personalized, and there is no rule of thumb as to which gear is best for any given athlete. And of course, this is a good example of where the art of coaching can add very real value. 

Image Source: https://www.thomasnet.com/articles/instruments-controls/dc-motor-controllers/

*When we talk about negative torque in cycling, we’re talking about positive speed with negative torque, which creates a forward breaking effect (q4 in the above diagram).

That is torque for (sprint) cyclists in a nut-shell.  It is certainly not exhaustive, but should give the readers an insight into why, what, and how to train for peak torque production (in the gym, and on the bike).  The next blog post in the series is about power… 

This blog is authored by BJ Olson in collaboration with Dave Bernard (author of Older Stronger Faster) and Glenn Catchpole of Velobike

Coach BJ is the head coach of Performance Cycle Coaching, and is an Elite Cycling and Strength and Conditioning coach.  He has worked with the US Olympic Development Program, Asian games Kierin athletes, among others.  If you’re interested in 1-on-1 coaching, or training guidance, you can reach out to Coach BJ at bj@cyclecoaching.net and at www.cyclecoaching.net