Build Endurance & Avoid Injury

In 2022, professional mountain biker Howard Grotts and professional ultrarunner Adam Peterman went back and forth on Strava segments in Missoula, MT. It caught my attention when Grotts set the running record at the local Mount Sentinel hill climb, a 2,000-foot, 1.5-mile climb out of town. 

How could a mountain biker keep up with a trail runner going up a steep mountain climb? 

You could say Grotts was talented, but there’s more to it than that. Grotts is an aerobic monster from years of training and racing at the top level in cycling. 

Cyclists put in the work–and lots of it. And running uphill doesn’t have the same biomechanical stress as running fast on flat or downhill terrain.

From a cumulative training perspective, cyclists can recover from the work faster than runners, allowing them to build huge physiological capacities. 

Cycling isn’t guaranteed to get you a KOM on the local running hill climb, but it can be a great tool in your training to build endurance and lessen your risk of injury.

How Do Runners Benefit From Cycling?

Runners turning to cycling for fitness often find they are limited by muscle fatigue more than by the cardiovascular system. This is largely because there are key differences in how muscles are put under tension during a running stride and pedal stroke. (You can see exactly what muscles cycling works in this blog.)

Over time, combining both types of exercise into your program can increase muscular endurance, increase overall training availability, and improve performance in both disciplines. 

Lower Impact at Higher Intensities

Many runners struggle to train consistently, increase their running volume, or incorporate higher intensity efforts because of frequent or recurring injuries. Cycling allows you to perform at higher intensity levels without dramatically increasing impact. 

Every time your foot hits the ground while running, your bones, muscles, tendons, and ligaments take up to 3x your body weight in “ground reaction force.”  Impact forces only go up as the speed of running increases.

Aerobic Adaptations

Cycling workouts can improve aerobic development for individuals who are limited by the number of running hours their bodies can tolerate. Training on the bike allows athletes to accumulate more time at a given cardiovascular intensity. 

When it comes to aerobic adaptations like increasing fat oxidation, increasing mitochondrial density, and expanding the capillarization of skeletal muscles, time at intensity matters more than the specificity of running vs. cycling. 

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Getting Started on the Bike

As a runner and running coach with extensive cycling experience, I like to have runners envision cycling workouts as a way to “isolate” the cardiovascular system from the muscular system. 

This is obviously an exaggeration, but it helps runners understand how different cycling and running can be from the standpoints of muscle stress and damage. 

To a runner, cycling at an easy aerobic pace is almost like hooking their heart and lungs up to a machine to get worked out while the leg muscles are over in the hammock taking a chill. 

If you choose, you can then use gears and intensity to add tension to the working muscles through low cadence, high torque workouts.

Cycling Heart Rate vs. Running Heart Rate

A trained runner who is new to cycling might notice a lower heart rate on the bike (by about 8-10 bpm) compared to a similar perceived effort during a run effort. With more time cycling, sport-specific fitness improves and biking and running intensity ranges become more similar. 

The oxygen cost of running at a given intensity is higher compared to cycling, so it will never be a 1:1 crossover. However, as researcher Dr. Stephen Seiler says, “training is an optimization challenge, not a maximization challenge.”  

To improve running performance, we need to increase your capacity to do work across a variety of intensities. Cycling allows you to do this while lessening your risk for injury from mechanical stress. It’s a balance between signal and response over time, and cycling could be part of finding this balance.

Aerobic-Building Cycling Workouts For Runners

If you’re ready to start adding cycling to your training, here’s a few workouts to consider. 

And if you don’t have a bike or access to cycle outside, don’t worry; all of these workouts can be done on an indoor trainer. 

Simple Rides for Base Building

Hopping on the bike is a great way to get your heart rate up without the wear of tear of running. Consider an endurance ride or hopping on the indoor trainer:

1. The Zone 2 Endurance Ride. This is a great way to accumulate a large amount of time in Zone 2 (easy, aerobic, conversational pace). Because the mechanical stress and muscle damage are so much lower compared to long runs, recovery times following 2- to 4-hour Zone 2 rides are much shorter (usually only one day).
2. TrainingPeaks Virtual. If you want to get in a great workout without worrying about traffic or your cycling skills, an indoor cycling setup on TrainingPeaks Virtual is a great solution.

   The list of routes includes hilly, flat, or long sustained climbs. You can upload your planned workout from TrainingPeaks right into TPV and get to work, making it easy to work in intensity or volume. 

Structured Cycling Workouts

If you’re looking to get a little more work out of your cycling sessions, try one (or all!) of these structured bike workouts:

1. High-Torque “Muscle Tension” Intervals
   The point of high-torque intervals is to pedal relatively slowly (50-60rpm) against a heavy resistance (e.g., big gear) for 5-10 minutes at a time. 

   Power is the product of muscular force and cadence. Low-cadence riding places greater emphasis on the “force” component of the equation, which means your legs recruit more muscle fibers to get the job done. The rating of perceived exertion (RPE) for muscle tension intervals is 6-8 out of 10. Over time, this helps with neuromuscular recruitment for high-force efforts. By engaging more muscle fibers, you also improve muscular endurance or durability.

   Incorporate this as a double day. AM: Endurance Run 1 hour. PM: Muscle Tension Intervals: 5 X 8 minutes w/ 4 minutes recovery between intervals.

2. VO2 max Cycling Workout
   This can either be a stand-alone workout or part of a double day after a one-hour endurance run w/ 4-6x 20-second strides.

   VO2 max intervals on the bike need to be short (3-6 minutes) for the sustained intensity to be high enough. A good starting point is a 7 X 3-minute power interval set with 3 minutes easy spinning between efforts. The rating of perceived exertion (RPE) for power intervals is 9-10 out of 10. This is a great way to incorporate VO2max training into a running program without inducing as much mechanical stress on your joints and muscles. 

3. Triathlete’s Brick Workout
   Runners can borrow a key training session from triathletes: running off the bike.

   In a split workout that starts with cycling, athletes can accomplish some specific time-at-intensity work on the bike and transition to an aerobic building endurance run.

   Example: 2-hour endurance ride with 4 X 15 minute tempo intervals (RPE 4-5) separated by 8 minutes easy spinning. Immediately transition to a 30-minute endurance run.

   The bike might take up the bulk of the time for this session, but the overall session is 2.5 hours with far less mechanical stress than a 2.5-hour run.

Try It Out!

Ready to give these workouts a shot? Try this free, four-week cycling plan for runners. 

(Note: this plan just includes cycling workouts and is designed to complement your run training.)

Pro tip: TrainingPeaks is a great tool to keep track of all your workouts (including cycling, strength training, or any other kind of cross-training) in one, cohesive place. This makes it easy to monitor your training load and avoid overtraining.

Important Caveat

Remember that the bike is a supplement to, not a replacement for, your run training. 

Running is the most important thing you can do to improve your running performance or prepare for a running event. 

In the long term, the goal should be to maximize the volume of run training you can sustain without injury or overtraining. Cycling can play a role in that journey by allowing you to discover new ways to enjoy aerobic activity.

References

Hohmann, E. et al. (2016, May 23). Plantar Pressures During Long Distance Running: An Investigation of 10 Marathon Runners. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC4879438/

Seiler, S. (2024, February 3). Dr. Seiler’s 12 Training Truths for Endurance Development. Retrieved from https://www.fasttalklabs.com/training/seilers-12-training-truths-for-endurance-development/