Hello, this is Sho!
Are you trying to get stronger while also improving endurance—but worried one might hold back the other? That’s the core challenge of concurrent training, a method that combines both strength and endurance work in a single program. It’s incredibly efficient for CrossFit athletes who want to perform better in every domain, but it also comes with a potential drawback called the interference effect—where endurance training may slow down your strength gains.
In this post, I’ll unpack what concurrent training really is, explore its benefits and downsides based on the latest research, and share practical ways to balance both strength and endurance so you can train smarter, recover better, and see consistent progress. Whether your goal is to lift heavier, move faster, or simply get the best of both worlds—this article will guide you through how to make it work effectively.
Table of Contents
- What is Concurrent Training?
- Concurrent Training Benefits for CrossFit Athletes
- Downsides of Concurrent Training
- Research on Concurrent Training
- How to Combine Strength and Endurance Training Effectively
- Conclusion
What is Concurrent Training?
Concurrent training involves combining strength training (resistance training) and endurance training (aerobic training) in the same period or even within the same session. This approach is particularly useful for sports that require a combination of strength and endurance, such as rugby or mixed martial arts. For CrossFit lovers, like myself, we often combine strength work and WODs in the same session, which means we might be engaging in concurrent training more frequently than athletes in other sports.
Concurrent Training Benefits for CrossFit Athletes
The biggest benefit of concurrent training is the ability to improve both strength and endurance at the same time. For athletes, this means they can enhance multiple fitness components simultaneously, making training more efficient. I started concurrent training and CrossFit about two years ago, and I noticed that not only did I gain muscle mass, but my cardiovascular endurance significantly improved compared to when I was doing strength training alone. If you don’t have much time for long training sessions, concurrent training can be a highly effective solution.
Downsides of Concurrent Training
On the flip side, concurrent training has a potential drawback known as the interference effect. This effect suggests that endurance training might reduce the benefits of strength training, potentially limiting muscle growth and strength development. However, I love the CrossFit style of training and refuse to believe it could hinder my gains! (Haha) In the next section, I’ll introduce some research findings that explore this issue and offer insights into how you can enjoy this training style to the fullest.
Research on Concurrent Training
Does endurance training affect muscle growth? Let’s take a look at some key studies that explore the effects of concurrent training:
1. Hickson (1980) Study: Interference of strength development by simultaneously training for strength and endurance.
Back in 1980, Hickson tested what happens when you mix strength and endurance training.
He found that people who did only strength work kept getting stronger,
but those who mixed both improved at first and then hit a plateau after about 7 weeks.
Their endurance still went up—but their strength stopped improving.
Basically, doing both helps your cardio, but too much mixing can hold back your strength gains.
2. Schumann et al. (2019): Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis.
Schumann and his team reviewed a lot of studies to see how mixing strength and endurance training affects results.
They found that doing both doesn’t really hurt muscle growth or strength compared to lifting alone.
It didn’t matter much whether people ran or cycled, how often they trained, or how experienced they were — the results were pretty similar.
The only downside was that when people did strength and endurance in the same session, their explosive power (like jumping ability) didn’t improve as much.
So, if your goal is to boost both strength and endurance, this combo works great — just try separating the two sessions if you want to focus on power.
3. Wilson et al. (2012) Study: Concurrent training: A meta-analysis examining interference of aerobic and resistance exercises.
Wilson and his team looked at how endurance training affects muscle and strength gains when combined with lifting.
They found that people who did both still built muscle, just a little less than those who only lifted.
Running tended to limit muscle growth more than cycling, probably because it puts more stress on the legs.
The same thing happened with strength and power — adding endurance slightly reduced results compared to lifting alone.
Still, it was way more effective than doing only endurance training.
The key takeaway: if you want the best of both worlds, keep endurance moderate and choose lower-impact options like cycling.
4. Kraemer et al. (1995) Study: Compatibility of high-intensity strength and endurance training on hormonal and skeletal muscle adaptations.
Kraemer’s study focused on how the body and hormones react when you mix high-intensity strength and endurance training.
He found that people who only lifted got stronger and built more muscle,
while those who did both had smaller strength gains and different hormonal responses —
especially lower testosterone compared to cortisol levels.
In short, mixing intense strength and endurance training can make your body lean toward “breaking down” muscle instead of building it,
so it’s better to plan recovery carefully if you train hard in both areas.
How to Combine Strength and Endurance Training Effectively
Based on the research, here are some practical tips for getting the most out of your concurrent training:
1. Adjust the Order and Timing of Your Workouts
If your goal is to improve explosive power (e.g., speed or strength), try separating your endurance and strength sessions by at least 3 hours or even do them on different days. This way, you can maximize the neural activation from strength training and minimize interference from endurance work.
2. Manage Training Frequency and Volume
If your primary goal is muscle growth and strength, limit your endurance training to 2 sessions per week, while focusing on 2-3 strength training sessions. The American Heart Association recommends 150 minutes of moderate-intensity aerobic exercise or 75 minutes of high-intensity aerobic exercise per week for general cardiovascular health.
3. Choose the Right Training Modality
Opt for moderate-intensity, shorter-duration endurance exercises rather than long-duration, high-intensity training like HIIT, which could interfere with your strength gains. Low-impact exercises like cycling may have less of a negative impact on strength training than high-impact exercises like running.
4. Customize Your Training Plan
Tailor your training plan based on your goals, fitness level, and training history. For example, if your current focus is power and strength, reduce the volume or intensity of endurance training. This way, you can maximize your results based on what you’re trying to achieve. I’ve also written an article about a strength training plan, so please check it out. here
Conclusion
While earlier research suggested that concurrent training may have negative effects on muscle growth and strength due to the interference effect, recent findings suggest otherwise. However, if you’re focusing on power development, it’s essential to carefully plan your training program. Ultimately, how much you want to fine-tune your routine is up to you! Enjoy your training, and if you’re aiming for specific results, use the tips from this article to optimize your concurrent training plan.
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