The following is an article Jennifer wrote for Active.com. To read the article on the Active.com website, click here. Please share the link (or this blog) with your students, program managers and instructor peers. As usual, your comments (both on the Active page and on this blog) are always appreciated!
The Truth About Indoor Cycling Cadence
As you peek into the door of many indoor cycling classes, or if you’ve watched some of the many “Spinning®” classes on Youtube or on television, often you will see frantic legs pedaling so fast it’s more like the roadrunner trying to escape Wile E. Coyote. Legs are blurring so fast you often cannot even see them. However, many students in typical indoor cycling classes do not have the skills to pedal quickly with good form. As a result, they bounce all over the place. It’s wasted energy that isn’t channeled into a productive output of power.
But, these students may be whooping it up along with the instructor and believe that they are working hard. I’ve seen instructors yelling at students to spin the legs faster and faster, sometimes in excess of 140rpm. Heart rates are high and sweat is flying, so the perception is that they are doing a lot of work. This unfortunately is the image of far too many indoor cycling classes.
If I could have a moment with these instructors and their students, I could prove to them that they really are not working as hard as they think they are, and therefore, they are not getting the benefits they imagine they are. Benefits such as aerobic development, muscular endurance, muscular strength, leg speed improvement, or even threshold or anaerobic benefits. The majority of them would achieve more and improve much more quickly if they would just slow down the legs and turn up the resistance knob.
Why We Pedal So Fast
One of the reasons for the excessive cadences indoors is the mechanics of an indoor bike. Its easy to pedal fast indoors! Most typical indoor cycling bikes are fixed-gear systems with weighted flywheels. The flywheels can be as heavy as 45 lbs and are often weighted on the circumference. This gives them inertia, and is responsible for the smooth feel as you pedal. While there are benefits to this, there are also implications on how fast you can, or should pedal, and whether or not that fast pedaling will improve your neuromuscular abilities and translate to faster cadences outdoors. As a cyclist, you have probably noticed that you can maintain a much higher cadence indoors than you can on your outdoor bike. The reason is because of that weighted flywheel. In reality, it is cheating.
If your club has these kinds of bikes with the weighted flywheels, here is a test you can do that will highlight this point. (Startrac Spinners or Schwinn bicycles older than a year or two are two common manufacturers of these bikes, though your club may have another brand with similar characteristics). Stand next to the bike and turn the resistance knob all the way to the left so there is no resistance. Now grab the pedal and turn it very quickly for about 7 or 8 good solid turns until the pedals and flywheel are spinning at well over 100rpm (use caution that you don’t get your finger caught in the pedal axel and stay out of the way of the moving pedal because if it hits you it will not stop). Now wait. You will see that it will take a long time, a very log time, before it slows down! This is because of the inertia in the weighted flywheel – it assists in the momentum of the drivetrain.
Because of this, all those unskilled riders pedaling at high cadences with no or insufficient resistance, bouncing all over the saddle, are basically strapped on to those pedals for the ride. They don’t have to do much work to keep them spinning at high cadences when the brake is not touching the flywheel. In a way, they are being ridden by the bike, instead of riding the bike. Without resistance, they will not achieve some of the fantastic benefits that indoor cycling provides. Because their heart rates may still be high, they interpret it as “work” and believe the calories burned number their heart rate monitors give them.
Sadly, this is not the case, and may very well be the reason why some people do not see the results they could be seeing in indoor cycling classes. It’s important to remember that heart rate is not always an effective indicator of how much work you are doing. Power measurement is much better. I know that power meters are still not very prevalent in fitness clubs, but that is slowly and surely changing as more and more adopt bikes with measurement tools.
The answer to success lies in that resistance knob!
How It Translates Outdoors
There is proof, if only I had the opportunity to show it to these riders and instructors. If they had a power meter on the bike, they would see that pedaling at high cadences and very low or no resistance actually produces a low power output. Heart rates are high because of the lack of technique, the bouncing and flopping in the saddle and the general inability to contract their muscles quickly. Poor technique is costly in terms of calories, yet those calories don’t translate to strength, fitness, muscular endurance or aerobic endurance benefits. It would be much better to channel the effort into a higher power output by raising the resistance and slowing the legs down. As mentioned earlier, power translates directly into calories burned; heart rate is only an indirect (and often incorrect) indication of how many calories are burned in an exercise session.
The next litmus test would be to put them on a road or mountain bike and ask them to pedal at 120-140rpm and sustain it. Very few people, except the most skilled cyclists, could do that for very long outdoors, although it’s somewhat easy to maintain indoors when there’s no resistance. In order to do this on a flat road, most would have to be in a granny gear. Pedaling at 120+rpm in that granny gear, their speed would be so slow that a child on a tricycle could probably pass them. Again, their heart rates would likely be high, but the lack of speed would be blatant proof that they are doing very little actual “work”. Outdoors, when your feet are flailing but you aren’t moving forward quickly, it’s a sign that you need to increase the gear. When you do, your cadence will slow down to (most likely) less than 100rpm but you will go faster. This means your power output is higher. Indoors, we don’t have the benefit of forward movement – or lack of it, to show the rider that excessive cadences and no resistance translate to little actual work.
So…how fast should you pedal indoors?
I haven’t given a range of “acceptable” cadences in an indoor cycling class because the answer is “it depends”. It depends on the skills and fitness of the rider and how much time is spent practicing. Just letting the legs spin fast out of control as happens in so many classes does not amount to practice. It is a waste of time. This is an excellent example of the adage “practice doesn’t make perfect, only perfect practice makes perfect.” You must perfect your technique first, then work on leg speed.
For the general population, I use an upper limit of 100rpm for most indoor riders. I have many students in my classes who are challenged at cadences over 90rpm, but that is because I’m a stickler for form, don’t allow any bouncing, and always make sure they have some resistance on the bike. This is much more similar to being in an outdoor situation.
If you are a cyclist who already has a smooth pedal stroke and who is used to pedaling at 100rpm or more outside, you certainly can do so indoors. Simply make sure that you are in control of the drive-train at all times and that you always have some resistance. You will know when you are being pulled around by the flywheel – there is a sense of being pulled along, as if by a zealous dog on a leash. To avoid this, work on technique by spinning circles. Try to minimize the focus on the downward phase of the pedal stroke. You are already very good at the part – you did it on your tricycles! Focus more on the bottom and top halves of the pedal stroke. The more you relax the upper body and the hips, while sitting deeper in the saddle, the easier it is for the leg muscles to contract quickly. By learning to “spin” instead of “mash” on a bike with a flywheel, you will be less susceptible to being “ridden by the bike”.
Check yourself in the mirror if there is one. You can see if you are bouncing. If there are no mirrors, have someone observe you from behind; it’s more evident looking from the back. Once you start bouncing, you have exceeded your cadence “threshold”. Back it down, and/or raise the resistance just a little until you find that right combination of resistance, at a cadence that is just beyond your comfort zone. For best results, do this without exceeding your anaerobic threshold; in other words, while staying aerobic and in control of your breath.
These tips are how you can improve your leg speed indoors and make sure that it translate to your cadence outdoors. If you do not commit this much time and focus indoors, then you will not likely find that your high-cadence pedaling in your standard, unaware, excessive-cadence indoor cycling classes has done you much good during the off-season.
Here’s to riding faster!
Thank you for this excellent article. I am new to spinning and been VERY frustrated by classes pushing speed, and not enough resistance. I knew right away I was developing very bad cadence technique, (mashing, bouncing and all things messy) and not getting much out of the class in terms of a workout. I realized early on that if I turned up the resistance and pedaled slower, (in the mid to high 80’s) my legs got an incredible workout, as opposed to spinning faster at lower resistance. This made so much sense from a strength training perspective, but is not pushed in most classes. So I stopped going to classes (except for the few instructors who understand this!) and created my own workout. I have gotten great results from your tips and enjoy spinning SO much more, and am ready to start cycling outside.
Aside from the spinning too fast with too little force, there seems to be another tendency (though more on regular bicycles outside the spin class) to think that FORCE = POWER and pedalling hard (but slow) = powerful pedalling. You can generate more force with a workshop vice than a sports car puts out at the wheels (after magnification with the arm and screw thread), but while the car has several 100hp, the vice only has 10s of watts from your arm muscles.
There’s a lot of ‘lugging’ slow cyclists around that even have the seat too low, increasing the ratio of muscular force to pedal force which will actually DECREASE pedal force as well!
Now Calorie burn is POWER divided by EFFICIENCY. All the factors effecting efficiency are beyond my knowledge, but two of them are load and form. Efficiency tends to zero at very high loads with little motion, and also low loads with lots of motion effecting form. I pedal a bike at a moderate 150 watts, which is a nice easy power so I pick 60-70 rpm. Calorie burn rate will be higher if I strain the pedals round at 15rpm (though I can’t sustain this as long) or pick unnecessarily fast 140+ rpm.
Calorie burn can also be increased by flailing your arms wildly, making punching motions with little weights, trying to bunny-hop the spin cycle across the floor, pressing up and down on the handlebars or rocking from side to side on the saddle! But you and I both know it is far better to concentrate on pedalling the bike!!
The adoption of the fixed gear mechanism on a lot of spin bikes always struck me as odd, unless one was training for track cycling. I think the majority of recreational riders would be more used to the freewheeling system on a regular bicycle. Whether it was adopted to ease maintenance or construction, or help with the anti-mashing problem above and increase the cadence of beginner riders I don’t know. Just for the record, the metal flywheel bikes in my big university gym were fixed gear and the one in my small local gym has a freewheel.
I used to go on the display screen exercise bikes that had more data on power, HR, Level, rough Calories, etc but the seats on most of them are a funny shape! (big wide saddle the size of a small chair seat!)
You are absolutely right Tim, if you are going to pedal that fast, you must have a load.
The equation P(watts) = F X V (force X velocity). Translated theoretically to indoor cycling terms, that means I (Intensity, either in Power or HR, but not a ‘unit’ of measurement) = C X R (cadence X resistance). That means you must have a force against which to push. This is one of the inherent problems in indoor cycling classes. The average student (think someone who does not ride a bike outside, many of whom have not ridden one since their tricycle days), as well as many instructors, do not understand this. Students see the instructor pedaling that fast, and the only way they can possibly copy him is to take all the resistance off. The equation Power = C does not work without the R (resistance). The relationship between F & V (R & C) is inverse. When F/R falls to zero, V/C cannot keep increasing indefinitely. Hence, they are lacking one important part of the equation, they bounce all over the place and they are missing out on most of the potential benefits. Sure, they are burning a few calories, but it it not as much as they think.
So, all this is to say, pedaling super fast indoors does not make sense in physical (as in physics), physiological or in fitness terms. The HR might be high, but it’s not because they are burning more calories. 140rpm indoors doesn’t make you a better cyclist or indoor cyclist, it doesn’t really apply to a productive leg speed (i.e. “specificity of exercise”) unless you are an Olympic level track cyclist perhaps, and with a weighted flywheel it doesn’t help your neuromuscular abilities (as it relates to leg speed). Except perhaps in the case of a pure explosive power effort, and as you mentioned, that is not sustainable….maybe 10-20 seconds maximum. And even then, maximal velocity of the flywheel (cadence) is only achieved in the last few seconds.
In the indoor cycling marketplace, there are very, very few free-wheel bikes on the market. CycleOps has a model that has a freewheel but I believe it’s more for the home market. There might be a handful of other manufacturers, but the market share is so low it’s not really a player right now. 99+% of the bikes I am referring to for indoor cycling usage at a fitness facility, have a fixed-gear system.
Now as for the flywheel helping you along, it depends on whether the flywheel is a fixed gear or a free-wheeler. I once pedalled really fast on one I was testing at Bath Gym and then locked my right leg suddenly assuming it was a free-wheeler and was almost thrown of the bike! So it’s a good idea to tell new class members what sort of bike setup they have.
These inefficient wobbly spinners WILL be working and improving their cardiovascular systems somewhat. What they won’t be getting is significant speed increase when riding and racing a bicycle, or muscular development.
What I find is that for really high cadences (>140), I’m smoother if I have a load. Too little resistance and I’m bouncing in the saddle before long.
I’ve had an electric resistance gym bike at 180rpm for 20seconds on maximum resistance 15/15 at 600 watts but this was by no means sustainable and I’d do even better sprints if a higher level existed. 90rpm 300 watts 15/15 20 minutes is what I call a maximum vigorous workout. I tend to look at power more than heart rate as it is hard to get an accurate display from the hand holds on the machine.
The problem is the instructor can see the speed of the pedals but can’t ‘see’ the resistance unless he looked at each flywheel through a thermal camera!