Time Is Limited, Train Effectively

If you are like most of us, you have limited training time. You have to train indoors and want to make the most of it. The closer your training device comes to a real outdoor pedaling motion, the better the results from your training.

The PFS provides a theoretically-sound pedal force over a full range of pedaling conditions including sprints and out-of-the saddle efforts and climbs, workouts that you can't do on trainers.

The PFS models power within a pedal stroke correctly. As a consequence:

• Hills feel like riding hills. When riding hills outdoors one's cadence naturally falls. And so it does on the PFS. This is a definitive indicator that the simulated pedaling is correct. Trainers don't respond this way.
  
  
• One can sprint out of the saddle. This allows you to train for sprints indoors without having to ride to a suitable training spot. One can train for sprints on a PFS; one can't on a trainer.

• One can train to climb long hills out of the saddle. On long climbs one needs to be able to vary one's position. Training to climb out of the saddle allows this. You can live in flat Florida and still train for long climbs using the PFS. One can't do this on a trainer.
  
  
• One can do standing starts. This is particularly useful for training for track events. One can't do standing starts on a trainer.
  
  
• Although less obvious, on the PFS simulated flat courses feel like they should. Trainers just never feel right even when spinning easy.
  
  
• By getting the force right at the pedal, the PFS allows one to duplicate indoors the subtle changes in position that come from increased power outdoors. Trainers don't get this right.
  

Principle of Operation

The PFS uses the standard validated model of forces acting on a rider to simulate instantaneous forces at the pedal.

It measures acceleration and, using the standard model of forces acting on the rider, applies a resistive force at the pedals that is theoretically equal to the force a rider would feel riding outdoors under the simulated conditions.

It does this using a brake that is electronically controlled by a computer in the resistance unit. The computer recalculates force at the pedals 1000 times per second so that the instantaneous force a rider feels at the pedal is always a theoretically correct force.

Features/Benefits of PFS

• A stand holds your bike and a roller applied to the rear wheel supplies the resistance. So the geometry of your position indoors is the same as your position outdoors. But there is another benefit. When you apply power outdoors, your position on the bike changes in subtle ways. By making the forces at the pedal theoretically sound, the subtle changes to position you see outdoors are duplicated on the PFS. This feature is beneficial to your training and would be beneficial for dialing in position in wind tunnel testing.

• The resistance unit has enough resistance to model the strongest rider. Even wimpy riders can generate high instantaneous power. The PFS is designed to model a complete range of instantaneous power and be able to control it precisely and quickly.
  

• The display on the handlebars is a high-end Palm device with a large, color display area. Display software takes full advantage of the Palm device's capabilities. We provide displays and plots of parameters. See the Photos, Screen Shot link. Workout data is saved to a sophisticated database. We provide all the measurement parameters you would expect.
  

• The display device communicates wirelessly with the computer in the resistance unit via Bluetooth. You can have the display device at the handlebars or your coach can hold it sitting across the room. A coach could control a group of riders from one central location.
  

• The display manages the parameters describing the conditions being modeled. It has a selection of typical courses that one can select for a workout. This lets you train indoors for specific conditions making effective use of your training time.
  

• Wind is modeled to be vary during a ride just as it does outdoors. Sometimes you may need to shift a gear because the wind changes. Yes, it is different pedaling into the wind. You can improve with practice.
  

• Multiple riders can share the device. The database keeps each rider's data separate from other riders. You can have as many riders setup as you want.
  

Instantaneous Pedal Acceleration

Have you noticed that when you are riding on a slight downhill with a tailwind that it really feels good? Have you noticed that as you go over the top of a hill that your power naturally drops? Have you noticed that your power is different riding on the flats verses riding up a hill? Have you noticed that your cadence naturally falls when climbing?

This is not your imagination. These are real effects. In each situation, the acceleration at the pedal is different and is a function of the mass of the rider and bike and of the forces acting on the rider. Instantaneous pedal accelerations affect the rider's ability to put power into the pedals. This effect exists all the time, not just in these examples, but in every pedal stroke.

Setup the Pedal Force Simulator to model pedaling down hill with a tailwind: it feels right. Model riding on the flats: it feels right. Model riding up a hill: cadence naturally drops.

The Pedal Force Simulator gets the instantaneous acceleration right because it is a theoretically-sound simulation of pedaling.

The more sport specific your training, the better your training will be.

Workouts, Training Software

Most training software treats a ride as one workout. Maybe this is OK if a long ride is your workout. But what if you are doing hill repeats as your workout? Can you tell from your training software if you are getting better at riding hills from one month to the next?

The PFS takes the approach that one often has workouts within a ride. The PFS defines a workout and records it in a database in such a way that it can be extracted and examined at a later time. Say one has been doing hill workouts for several months and one wanted to see if the time to the top was getting less. One could extract from the PFS database all the hill workouts over the several month's period and examine them to see how well one was doing.

The PFS also allows one to define a workout and let the PFS conduct it. Say one wants to do criterium intervals, three sets of six reps with 25 seconds efforts followed by 15 seconds of recovery. Try keeping that straight in your mind when you are making an effort. The PFS will conduct the criterium interval workout for you signaling when to start and stop efforts and recovery. It records the workout into its database so that criterium intervals over, say several months, can be compared.

This is a different way to look at one's training time. We believe it to be a useful conceptual apporach.

More About Trainers

The more expensive trainers let a rider select simulated conditions and from these conditions calculate the average power needed for a measured speed. There is some entertainment value to selecting parameters, but once this selection has been made, the resistive power is a constant function of speed.

Less sophisticated trainers have one speed versus power curve and resistive power is always the same at the same speed.

In both cases pedaling feel is not realistic. It's unrealistic because the acceleration within the pedal stroke is not realistic. Trainers, even ones with large flywheels, can't duplicate the acceleration profile of riding outdoors. It takes a much more sophisticated approach.

People ask if one can simulate outdoor riding with a flywheel and trainer-type resistance. I did a study of this and concluded that it was just not possible because a flywheel and resistance approach can't duplicate the acceleration within a pedal stroke that characterizes riding outdoors. Accelerations of some trainers in the analysis were off by a factor of as much as 1000.

The PFS measures acceleration and recalculates resistive power 1000 per second within the context of the simulated conditions. It controls the instantaneous resistance using a computer-controlled electronic brake. The result is a much more effective way to spend one's limited training time.

What's Wrong with Trainers?

Trainers don't feel right.

You know this as soon as you get on a trailer. It's especially obvious when you get up to sprint or ride out of the saddle. You simply can't do it on a trainer.

Why? When you stand to accelerate outdoors the pedals "push back harder" than when seated. This increased force is the effect of trying to accelerate the rider and bike.

Trainers model average power at constant speed: they don't respond realistically to accelerations. So when you get up to sprint on a trainer, the pedal "falls out from under you". The acceleration of a trainer is wrong, wrong by as much as several orders of magnitude. After all, the mass of even a large-flywheel trainer is small compared to the mass of a rider.

Acceleration is the root cause of the difference.

The PFS creates forces at the pedal that are a theoretically-sound simulation of outdoor pedaling forces, a much better simulation of real-world pedal forces than today's trainers. It gets acceleration correct. Pedaling feels right because it is right.

This specificity benefits your training.

Why Does It Matter?

Why should pedaling correctly matter?

The more "sport specific" one's training, the better.

The PFS creates forces at the pedal that are a theoretically-sound simulation of outdoor pedaling forces, a much better simulation of real-world pedal forces than today's trainers.

Because it does, you can:

• Climb out of the saddle and it feels like climbing out of the saddle should.
  
• You can sprint out of the saddle.
  
• You can do standing starts.
• Your pedaling motion on flats is correct.
  
• Your position on the bike changes with increased power the way it should.
  

Effective cycling is about pedaling the bike well. You know a trainer is wrong as soon as you get on it. Why use an ineffective device when you could use the right one?

Project Status

Prototypes are complete, fully functional, and tested. Yes, it works really well. Focus group comments were all positive.

The software is complete, fully functional, feature rich, and tested. The display could be easily ported to another display device including a PC.

Am currently offering licensing of technology. Am willing to consider creative offers.

If you know of someone that I should contact regarding licensing, let me know.

Why This Blog?

I have always thought trainers did a poor job of simulating outdoor riding. I gave some thought as to why and came up with a device that does a much better job. I developed a prototype and call it a Pedal Force Simulator.

The purpose of this blog is to promote this project.