Cross Training for Runners: How to Build Fitness Without Extra Impact

By RunDoyen.
Featuring coaching insights from David Jankowski and Michelle Chewins.
Adapted from a RunDoyen coach conversation and edited for clarity.

TL;DR

• Cross-training is endurance work that helps you gain fitness or recover when you cannot run, or when running more would be risky.
• It is different from strength training, drills, and mobility work.
• Use it for four common scenarios: injury, injury prevention, supplementing volume, and weather or travel safety.
• Pick a modality you can be consistent with (bike and pool are common “workhorses”).
• Structure cross-training like running: easy days, workout days, longer aerobic sessions, and recovery sessions.

Table of Contents

• What counts as cross-training (and what does not)
• The four best times to cross-train
• Choosing your cross-training mode
• How hard should cross-training feel
• Sample cross-training sessions you can copy
• How to stay motivated when cross-training gets monotonous
• Common mistakes
• Safety and when to get help
• Putting it into your training week

What counts as cross-training (and what does not)

In a runner’s training plan, “cross-training” can mean a lot of things. For this guide, keep it simple:

Cross-training is endurance-focused work that helps you gain fitness or recover when you are not able to run, or when you should not run more.

What it is (in this context):

• Bike workouts (indoor or outdoor)
• Swimming workouts
• Aqua jogging (pool running)
• Elliptical
• Rowing
• AlterG (if you have access)

What it is not (in this context):

• Strength training
• Med ball work
• Agility drills
• Mobility and rehab exercises

Those tools matter too, they just serve a different purpose.

If you want cross-training built into a plan that matches your injury history, schedule, and race goals, you can get matched with a running coach who can adjust the right levers week to week.

The four best times to cross-train

Cross-training is most useful when it is doing a specific job. Here are the four situations where it tends to deliver the biggest return.

1) Coming back from injury

If you cannot run, cross-training becomes your fitness “bridge.” It keeps you moving while you wait for tissues to calm down and for your return-to-run plan to start.

A practical way to think about it: once you are cleared for activity, you can structure cross-training like a normal training week, then progress it over time.

2) Avoiding injury, especially when something is nagging

One of the simplest injury-prevention habits is being willing to swap a run for cross-training early.

A useful rule of thumb from coaching: if something is bothering you for more than a day, it can be worth replacing a couple days of running with cross-training. The point is not to panic, it is to avoid turning a small problem into a long layoff.

3) Supplementing volume when running more is not an option

Many runners hit a ceiling where more running volume starts to create problems.

Cross-training can help you keep the aerobic volume you need while reducing impact. A real-world example from coaching is the athlete who could not safely reach the same mileage as teammates, but supplemented with bike and swim sessions to close the gap in total workload.

4) Weather, travel, and safety

Sometimes the smart training choice is simply the safest choice.

Cross-training can replace runs when:

• It is icy and you are likely to wipe out
• Air quality is bad
• You are traveling in an unfamiliar area, or somewhere you do not feel safe running

Consistency beats heroics.

Choosing your cross-training mode

Different tools fit different runners. The goal is not to find the “best” modality, it is to find the one you will actually do consistently, and can do hard enough to matter.

Bike

The bike is often the most accessible option, and it is excellent for stacking aerobic volume without pounding.

It is also easier to “work” on a bike than many runners expect, especially once you start using short intervals or controlled surges.

Swimming and aqua jogging

Swimming is a strong fitness builder, but it depends on skill and comfort in the water.

Aqua jogging is a great option when you want a running-adjacent movement pattern without impact. You can also replicate run workouts in the pool by doing fartlek-style efforts.

If you hate the pool, that matters. You are more likely to get quality work done doing something you do not dread.

Elliptical

Elliptical is a practical compromise. It is low impact, accessible in most gyms, and it is easy to control effort.

Rowing

Rowing can be a solid option if you have access. It is also easy to overcook if you go too hard too soon, so build into it gradually.

AlterG

AlterG can be a powerful return-to-run tool if you have access. It is commonly used as a step between fully non-impact training and running on land.

How hard should cross-training feel

Cross-training can serve different purposes, so intensity should match the purpose.

Recovery cross-training

This is your “flush” session. It is designed to get you moving and feeling better, not to impress anyone.

In plain language: you should finish feeling looser, not cooked.

Aerobic volume cross-training

This is your steady, controlled work. It is the session that replaces easy mileage or extends total aerobic time when running more is risky.

You want it honest, not mindless.

Workout cross-training

This is where many runners underuse cross-training. When your goal is fitness maintenance or fitness gain, workouts matter.

You can:

• Convert a run workout into timed intervals on the bike
• Use fartlek-style efforts in the pool
• Use interval ladders to keep your mind engaged

General guidance: Heart rate can behave differently across modalities. Some runners use RPE (effort) plus a simple structure (intervals, surges, recoveries) to keep sessions productive without obsessing over a number.

Sample cross-training sessions you can copy

Below are practical sessions pulled from coaching approaches described in the conversation, including one standout bike workout.

A simple cross-training menu

Goal	Modality	Session length	Example session
Easy flush	Bike or elliptical	20–40 min	Easy spin with a few short pick-ups
Aerobic builder	Bike, swim, elliptical	40–70 min	Steady effort, controlled and sustainable
“Workout day” replacement	Bike or aqua jog	35–70 min	Intervals based on time (not distance)
Long-run simulation	Bike or pool	60–120 min	Longer steady session, add short surges if needed

The bike ladder workout (highly repeatable)

This one is simple and deceptively hard.

1. Warm up 10–15 minutes.
2. Start the ladder (each step is 1 minute total):
   • 10 seconds hard, then easy to finish the minute
   • 15 seconds hard, then easy
   • 20 seconds hard, then easy
   • Keep going until you reach 60 seconds hard
3. Easy spin 2–4 minutes.
4. Repeat the full ladder 2–4 times (based on your fitness and why you are cross-training).
5. Cool down 10 minutes.

Converting a run workout to the bike (simple approach)

If your plan called for K repeats or mile repeats, you can often convert them to time-based bike intervals.

Examples from coaching:

• K repeat feel becomes a timed interval, often around 3 minutes of work
• Longer repeats (like mile or two-mile repeats) become longer reps, often 10–15 minutes, with recovery between

The idea is not perfection. The idea is matching the intent of the day.

How to stay motivated when cross-training gets monotonous

Cross-training is mentally harder than most runners expect, mostly because it can feel repetitive.

Here are strategies that help runners stay consistent:

• Pick the modality you will actually do. If you dread the pool, lean into the bike. If you love swimming, use it.
• Keep weekly structure. Easy days, workouts, longer days, even if you are not running. This helps your brain feel like you are still “in training.”
• Use intervals even on aerobic days. Short surges or ladders keep you engaged.
• Rotate modalities. Bike one day, swim the next, elliptical another day.
• Use a class environment if you love it. A spin class can solve motivation fast.

Common mistakes

• Treating cross-training like a throwaway session, then wondering why it did not help.
• Choosing a modality you hate, then skipping it repeatedly.
• Going so easy that it becomes pure “movement,” when the goal was fitness.
• Going so hard every day that you never recover, especially if you are also running.
• Obsessing over heart rate in the pool, where cooling can make numbers misleading.
• Using AlterG miles as if they were identical to running miles on land.
• Waiting too long to swap in cross-training when a niggle shows up.

Safety and when to get help

Cross-training is still training. If you are returning from injury, it is smart to follow clearance guidance from a qualified professional.

Consider getting help if:

• Pain persists even after a few easier days
• Symptoms change your gait, or get worse as you train
• You cannot find an effort level or modality that feels safe

If you are dealing with a suspected bone injury, severe pain, or symptoms that concern you, consider consulting a qualified clinician.

Putting it into your training week

Cross-training works best when it is planned, not improvised.

Two practical ways to use it:

1. Swap one run for cross-training each week to reduce impact while keeping volume.
2. Use cross-training as your “double.” If you cannot safely run two-a-days, a short bike or swim session can be a lower-impact second session.

If you want a plug-and-play structure, RunDoyen’s Training Plans can give you the weekly framework, then you can swap cross-training in where needed.

If you want a coach to help you choose the right cross-training mix for your goals and injury history, you can browse our running coaches and find someone whose style fits your training.

FAQ

1) Is cross-training as good as running for fitness?
Cross-training can maintain, and sometimes build, aerobic fitness, especially when sessions are structured with workouts and longer aerobic efforts. It does not perfectly replicate running, but it can be a powerful tool when running more is not possible.

2) What is the best cross-training for runners with injuries?
Bike and pool work are common choices because they reduce impact. The best option is also the one you can do consistently and safely without aggravating symptoms.

3) How do I convert a running workout to the bike?
A practical approach is to match the intent of the session using time-based intervals. For example, shorter repeats can become a few minutes hard with recovery, and longer repeats can become 10–15 minute reps with recovery.

4) Is aqua jogging worth it if I hate it?
If you hate it, consistency becomes the problem. Some runners do better choosing a bike or elliptical instead. If you do use aqua jogging, intervals can make it much more tolerable.

5) Should I track cross-training as “miles”?
Many runners track cross-training as minutes rather than miles, since effort and carryover vary by modality. If you like tracking, keep it separate from running mileage so you do not confuse training load.

6) When should I choose cross-training instead of running?
Common times include injury recovery, early signs of a nagging issue, icy or unsafe conditions, or when you want to add volume without adding impact.

7) How can online run coaching help with cross-training?
An online running coach can decide where cross-training fits (recovery, workouts, or volume), adjust the week when niggles show up, and help you progress intensity and duration so cross-training supports your running instead of replacing it randomly.