VHS vs BetaMax
How marketing has made indoor trainers worse for indoor training
Indoor training for cyclists is not a new idea. Some time in the early 80’s indoor trainers - the stand that a road bike would go on, became popular (when I say popular, I mean with the sort of person who would torture themselves in their basement on a bike that wasn’t going anywhere). The first trainers used a simple swirl cage fan to move air - the simplest resistance system. It provided resistance and noise, not in that order. The noise was a pressure disturbance that didn’t stop at walls, it had to go. The next big thing was the magnetic trainer. Magnetic resistance works by rotating a metal disc between rows of offset magnets. The resistance is linear, it doesn’t change with the speed that the disc is spinning. This disturbed people because it’s not like riding on the road. On the road, as the speed increases the resistance increases exponentially.
This is where the first marketing assumption comes in. The assumption is that riding on a trainer should simulate everything about riding on the road. Smart trainers today are sold based on their “road feel”. Most other sports have figured out that off season training is a time to apply the overload principle to various aspects of the sport. Strength training for example, not the same as the sport, but beneficial to it. With cycling the season starts in the spring and by the fall riders are starting to slow down - what would make you think more of the same is the right course of action? It’s not, but your local bike shop can sell you a smart trainer with wonderful road feel, and you can get on Zwift and ride with your virtual friends just like it’s summer (without the need for sunblock).
In the quest for a trainer that gave exponential resistance someone had a brilliant idea - build a bucket around a wind trainer fan and fill it with oil. The fluid trainer was invented. It had the same type of resistance as the wind trainer without the noise. At the same time the smart trainer was in it’s infancy. It was called the Computrainer, a bicycle based video game with something called SpinScan, which spawned even more marketing BS. With fluid trainers taking over the market, magnetic trainers found their way into the discount bin. Low end trainers were magnetic, high end trainers were fluid, Computrainers were owned by the privileged (and the nerds).
The explosion of smart trainers in the market wasn’t because of the smart trainers, it was how they would handle the software end of things. Computrainers used their own software and needed a PC to run them. There was a choice of 1 program, it was like when video games were all Pong. Wahoo came out with a trainer that was app based and let third party software developers go nuts. They went nuts, Zwift was born, now you can ride your bike under the ocean or in the London tubes. Other companies jumped on the bandwagon, now you have lots of options for smart trainers. Wheel off (replacing the rear wheel and cassette) trainers have taken their place at the high end of the food chain, wheel on smart trainers are seen as a step down from that. That leaves the poor fluid trainer at the “can’t afford a smart trainer” level and the magnetic trainer is below the poverty level.
Marketing needs metrics and people want things boiled down to one number, so the cycling world settled on the watt. A watt is a unit of power. In the context of a pedal stroke, wattage is the sum of the normalized forces around the pedal stroke X the cadence. That amount of power applied to the rear wheel of a bike determines the speed of the bike. As a measure of power the watt works great, other variables can then be compared. Efforts of riders are often quantified as watts/kilo…
Smart trainers calibrate in wattage - there is an issue with that. Torque is a measure of twisting force, using linear force and the length of the lever arm as units. 2 newton meters is roughly the torque generated by two fig newtons on the end of a yard stick (I did say roughly). As trainers are dealing with a tire on a roller, and the radius of the wheel isn’t changing, we can cancel out the yard stick and just refer to linear force. Watts is a measure of torque X angular velocity, if the speed of the resistance unit increases, so does the wattage. Smart trainers’ control parameter is wattage, which is always changing with the speed of the resistance unit.
Let’s get back to the purpose of winter training. Winter training is about breaking cycling into it’s component parts, and working each aspect harder than you could by just riding. Making the rider more efficient within the pedal stroke is a large part of that. To be able to do that, we need a constant resistance at the pedal to learn muscle group isolation and timing. A magnetic trainer does that perfectly, the smart trainer can’t. In applying the overload principle to using the glutes on the bike, there needs to be high enough resistance at a low RPM. With it’s exponential resistance, a fluid trainer won’t give enough resistance at low cadence, but a magnetic trainer can.
The marketing says “you need a smart trainer, you need to train on power (watts)”, but every method shown to change motor skills or muscle strength doesn’t have a time parameter. Weight lifters talk about lifting a certain weight, not lifting a weight at a certain speed - form + muscle tension are all that matters. Learning pedal stroke timing and applying load to muscles on the bike is the same. Watts are simply the wrong unit of measurement.