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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