Once we understand and move past the limitations of cadence on the indoor bike, we can begin to realize how much of the focus of our class can be affected by leg speed. I”™m not just talking about cadence drills and biomechanics, but actually controlling how much stress we place on the cardiovascular system and how much stress we place on the muscular system (legs). Although little scientific study has been done on the effects of cadence, there is substantial practical evidence from years of cycling, training and competition to grasp the overall impact of cadence on the body.
Keeping in mind that there are always exceptions, it has been generally accepted that 80 RPM is the imaginary line between cardiovascular and muscular emphasis. More specifically, a cadence of 80 RPM or higher will demand more from the cardiovascular system where a cadence less than 80 RPM will place greater focus on the musculature of the legs. Similar to how our energy systems and fuel systems work, there is not a specific “cut-over” from cardiovascular to muscular, but rather an emphasis or greater percentage of one over the other.
A more technical way to think about it is to consider the concept of force (or torque) and velocity. The more velocity (faster cadence) for the same amount of output (such as power) the less torque or stress on the leg muscles. Similarly, the same power with a slower leg speed will require more force (torque) and place a greater emphasis on muscle engagement. If you have a power meter that measures torque (in newton metres - Nm), you can see the impact of cadence as you try to hold the same power output with different leg speeds.
So what does this mean for Indoor Cycling?
Well it means a lot. An instructor can guide riders toward a certain focus by encouraging a leg speed that provokes the right physiological response. For example pushing a rider to a perceived effort of 80-85% with a 90 RPM cadence will place a great amount of stress on their cardio system. The rider will most-likely feel as if their ability to breath is being severely challenged. Pushing a rider to the same 80-85% perceived effort using a 60 RPM cadence will place a tremendous load (and emphasis) on the leg muscles. The rider will most-likely feel as if they can sustain their breathing but their legs will soon give out. The same target intensity but a totally different response.
So think about the type of training effect you are trying to promote and what you want your riders to feel during different parts of your class and make sure the suggested cadence is appropriate. This may also help guide those who are pedaling too fast during an effort focused on muscular endurance. Explain both the target cadence and how their legs should feel to entice them to decrease their leg speed and increase the resistance. Conversely, lure the pedal masher to a faster leg speed (with less resistance) to transfer the emphasis from the legs to the lungs.
Suggested Cadences:
- Warm-up: 80-90 RPM
- Aerobic Endurance: 80-100 RPM
- Muscular Endurance: 70-80 RPM
- Muscular Strength: 60-70 RPM
- Threshold Training: 90-100 RPM
- Climbing: 60-80 RPM
- Sprinting: (See Part 4)
- Cool-down: 80-90 RPM
Give Em a challenge: CLIMB LIKE A PRO CYCLIST
It is not uncommon for riders in an indoor cycling class to slow their cadence to 60 RPM with tons of resistance when simulating a climb. Instead, encourage them to climb like a pro (or maybe Tour de France) rider by maintaining an 80 RPM cadence while climbing. Many pro cyclists will climb at faster leg speeds because it produces more power (remember the force-velocity relationship). However, the reason they can maintain this is due to their aerobic ability (or capacity). When we climb at an 80 RPM cadence, in or out of the saddle, we feel our lungs beginning to burn and our natural response is to slow down the legs to ease the pain in our chests. So, bring your riders to a 80 RPM cadence either through a cadence check or music that indicates the tempo. Then have them continue to add resistance until they are barely able to maintain the leg speed. That is the baseline for the climb. You can give them the option to stand while climbing, but they must maintain their 80 RPM cadence even out of the saddle. Keep the climbs short (2-5 minutes). Ask riders if they were successful in being able to visualize the climb at the faster cadence AND if they felt the stress in their lungs even through they were climbing. This is a great way to demonstrate the power of cadence and how we can manipulate the way our body responds to intensity.
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Tom…..I’m so glad you posted when you did as I’ve had cause to think about this “cadence conundrum” just this week and you’ve put a few things in perspective.
Even at my gig with the Keisers, I have a handful of class members who’ll be grinding when the cues prescribe something in the 90 rpm ballpark. Thing is, on a stationary bike in a 45 minute class the trade-offs to pedalling like this don’t come back to bite you in the butt in the way they would in the Real World. However, one of the “grinders” approached me after class to ask where I thought she and her husband should ride to practise their gear changes etc. as they’d just bought a pair of bikes…….someone does listen after all.
Now, the reason why I’m pleased to read this post is that I’m putting together a few ideas to get the point re: a realistic cadence across in a more tangible way than I seem to have done so far. It’s quite amusing in a way because, at the places where I’ve taught on the Spinner bikes with the weighted flywheel etc., it’s usually a hard sell to get folk to drop their cadence below egg-beater speed and now, I’m looking for a way to get the idea of picking up the cadence a bit.
Here’s my take, Tom……and I’d welcome a critique…..but, it’s my perception that as nice as it is to be strong (and I do love me “strength” rides) leg strength isn’t in and of itself the ultimate limiter to performance. This particular class member could prolly wipe the floor with me grinding out her watts over a 10-minute spell (with one or two upper body stretches and other excuses to back off) but get out for a real ride and she’d be sucking wind big time before too long. Just like my husband is way stronger than I am but whenever we’ve been out together, I have to keep circling him so he can keep up because, because as much as he can grind for a short time in a big gear, he lacks the basic endurance that I’ve trained in me.
For a him ‘n’ her combo that’s riding together, a woman has to train really smart to be able to keep up with the strength that most guys possess. I think this might be a selling point for actually listening to my cues on cadence
Vivienne
I started working on 80 RPM+ climbs with my class 2 years ago. At first they thought I was totally nuts, but when they saw how much they improve and heard from the outdoor riders that their outdoor climbing had improved too, they were converted. Now they can all manage a pretty long 80RPM climb and we are working on extending our standing times.
There is a study, I think a joint one by the Universities of Wyoming and Wisconsin (although my memory could be faulty on that), that shows that slow muscular endurance climbs tend to predominately use the glycogen stored in the muscles, hence the muscle fatigue. When I explain this to my class, in simple terms, of course, and point out how professional riders use this as part of their race strategy, they get it.
Tom,
Thank you for another excellent post. We are climbing and riding at 80 more and more (65-80, generally). I know that some elite cyclists can ride 80+ rpms…it is a goal of ours…
do you recommend this for people who ride indoors in classes?
Most of the members do not ride outside.
MrWilson