The Hazards of Riding Too Slowly

Why too much resistance and too slow a cadence is a bad combination.


Since indoor cycling involves pedaling to nowhere on a stationary bike, you might think your pace really doesn't matter. But that’s not true. Your cadence is an important factor. Just as riding super fast with little resistance on the bike is ineffective, perhaps even dangerous (if your feet slip out of the pedal cages or clips), pedaling too slowly with heavy resistance on the bike is also risky business (and concern about getting bulky thighs should be the least of your worries).

Loading on the resistance to the point where it’s a struggle to keep the pedals moving smoothly and your cadence drops to 40 or 30 RPMs might make you feel like you’re really pushing your limits but it’s not a good idea. You might think that you’re activating your slow twitch muscles or building greater muscle strength but you may just be putting excessive stress on your knees, hips, and lower back. (This is one reason the Spinning® program advises keeping your RPMs above 60 when climbing a hill.)

You’ll also cause greater and faster muscle fatigue and deplete your glycogen stores (forms of glucose your muscles rely on for energy) more quickly. Research from Hungary found that with heavier resistance and slower cadences, activity in the hamstring muscles increases at a higher rate than quadriceps activity does; if done regularly, this pattern could lead to the development of muscle-strength imbalances and injury.

What’s more, if you end up pulling on the handlebars to get the force you need to keep the pedals turning when you’ve cranked up the resistance, you could injure your shoulders and upper back, too. This is another reason why it’s essential to maintain good form—by keeping your hips, knees, ankles, and feet in their proper alignment—when you’re pushing heavy resistance and/or cycling at a slower cadence.

So here’s the upshot: If you really want to build leg strength, you’d be better off getting off the bike and going to the strength-training area of the gym to use weight machines or do squats and lunges. If you want to crank up your sprint and endurance performance, increase your resistance but also keep your RPMs above 60. A 2009 study from New Zealand found that when competitive cyclists performed sets of high-intensity cycling sprints at a low cadence (60-70 RPMs) in training sessions on stationary bicycles over four weeks, they improved their 60-second average power and their peak power more than those who did sets of high-intensity sprints at a high cadence (110-120 RPMs) did.

Some exceptions to this guideline: If you're a seasoned cyclist and you want to train to climb steep hills outdoors or really challenge yourself indoors, my feeling is that it’s okay to let your pace or cadence drop to 50 RPMs when there’s heavy resistance on the bike—but only for brief periods of time (two minutes or less at a go).

But don’t sacrifice your form—that’s not negotiable! If you can’t sustain a 50-RPM pace or maintain proper form at a heavy resistance, you’d be better off dialing down the resistance or dropping a gear so that you can stay above 50 RPMs and maintain optimal cycling posture. If you need to contort your body or pull on the handlebars to keep the pedals turning, you have too much resistance on the bike—it’s that simple!

Ultimately, it’s not worth the risk of straining a leg or glute muscle, your back, or a joint to max out the resistance on the bike. With indoor cycling, you’re trying to build fitness, endurance, and cycling technique, not feed your ego. Pace + resistance will get you to the right prize.

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