- Yes, you can build strength and endurance at the same time. The much-feared interference effect primarily slows down maximal strength and explosive strength slightly—muscle growth (hypertrophy) remains largely unaffected, according to research.
- The meta-analysis by Wilson et al. (2012), which included 21 studies, shows that running interferes with strength training more than cycling, and the greater the volume and frequency of endurance sessions, the greater the interference.
- Practical Tips: Do strength training first (if you're doing both in one session), space out your strength and endurance sessions (ideally 6+ hours apart or on different days), and pace yourself with endurance training.
- For most recreational athletes, the effect is so small that proper recovery and nutrition are more important than the perfect sequence.
Combining Strength and Endurance: How to Do Concurrent Training the Right Way
Strength and endurance can be developed simultaneously—the famous interference effect is real, but significantly smaller than its reputation suggests. The large meta-analysis by Wilson and colleagues (2012, *Journal of Strength and Conditioning Research*) summarizes 21 studies and finds only a small to moderate reduction in maximal strength and power, while muscle growth is not statistically significantly impaired.
For you, this means: If you want to be both strong and endurance-oriented—whether as a Hyrox or CrossFit athlete, a runner with strength goals, or simply someone who needs both in everyday life—you don’t have to choose. You just need to plan wisely. This guide shows you what the interference effect really is, which factors amplify it, and how to structure your week so that both goals can grow side by side.
What is the interference effect?
The term was coined by physiologist Robert Hickson in 1980. He observed that subjects who trained for both strength and endurance at the same time developed less maximum strength than athletes who focused solely on strength training—their endurance, however, developed normally. This observation became the foundation of concurrent training research.
The reason lies in the different adaptive signals sent by muscle cells. Put simply, strength training activates the mTOR signaling pathway, which drives muscle protein synthesis and, consequently, muscle growth. Endurance training activates AMPK, which focuses on energy efficiency, mitochondria, and endurance capacity. Under certain conditions, these two signals can inhibit each other—especially when a lot of endurance training takes place immediately before or after strength training, leaving the body too little time to recover.
How big is the brake, really?
Significantly smaller than many people think. In the Wilson meta-analysis, the impairment in strength and power fell within the range of small to moderate effects—hypertrophy was virtually unaffected. More recent studies, such as the review by Schumann and colleagues (2022), emphasize that when training volume and frequency are carefully coordinated, the negative impact on muscle size and explosive strength often disappears entirely. The interference effect is therefore not a law of nature, but rather a matter of dosage and planning.
These factors increase the interference
Research shows quite clearly which factors determine interference. If you know what they are, you can almost completely neutralize the effect:
| factor | Little interference | A lot of interference |
|---|---|---|
| Endurance Modality | Cycling, rowing (gentle on the joints, low eccentric load) | Running (high eccentric load on the legs) |
| Time interval | Different days or at least 6 hours apart | One right after the other in the same unit |
| Endurance Volume | Short, moderate-intensity workouts | High volume, long runs, many sessions per week |
| Order (same unit) | Strength first, then endurance | Exhausting endurance training right before strength training |
| Affected Quality | Hypertrophy (minimal involvement) | Maximum strength and explosive strength (most sensitive) |
In short: A recreational runner who goes for a moderate jog twice a week and does strength training three times a week will hardly feel any strain. An ambitious marathon runner who completes six long runs a week and then does heavy squats afterward will certainly feel it.
Order: Which Comes First, Strength or Endurance?
This question only arises if you do both in a single workout. In that case, the rule of thumb is: Train the aspect that’s most important to you first—because it benefits from a fresh nervous system. For most people who want to get stronger, that means strength training first, followed by endurance training. Heavy compound exercises like squats or deadlifts require full neural control; after an exhausting running session, your form is poorer and the risk of injury is higher.
If, on the other hand, your main goal is to improve your running performance, it may make sense to do the endurance session first. The more elegant solution is almost always to space them out: strength training in the morning, endurance training in the evening—or on separate days. The greater the time between them, the less the adaptation signals compete with each other.
Here's How to Plan Your Weekly Workout Schedule
A practical framework for three to four strength training sessions plus two to three endurance sessions might look like this: strength training on set days (e.g., Monday, Wednesday, Friday), endurance training on the days in between or well spaced apart on the same day. If possible, avoid scheduling high-intensity interval training (HIIT) immediately before a heavy leg day—your legs need that strength. Light cycling or Zone 2 endurance training, on the other hand, hardly interferes at all and can even support recovery.
If you do functional and hybrid training, you’ll find the right equipment in our Functional Training collection; classic strength training machines, dumbbells, and racks for the strength portion of your week are available in the Strength Training collection. And because concurrent training means a higher overall workload, it’s worth taking a look at the recovery tools —sleep, mobility, and active recovery often determine whether hybrid athletes make progress or hit a plateau.
Buying Guide: What to Look for in a Hybrid Setup
Fuer Zuhause oder Studio brauchst du keine zwei getrennten Welten. Ein stabiles Rack mit Langhantel deckt den Kraftteil ab, ein hochwertiges Ausdauergeraet (Rudergeraet oder Ergometer) den Ausdauerteil - beide gelenkschonender als Laufen und damit interferenzarm. Achte auf Belastbarkeit, Standfestigkeit und Garantie statt auf den niedrigsten Preis: Gerade Hybrid-Training bedeutet viele Wiederholungen ueber Jahre. Als autorisierter Haendler mit voller Herstellergarantie und Ratenzahlung ueber PayPal oder Leasing bekommst du bei Kraftathlet Marken-Equipment, das diese Belastung mitmacht. Unser Team beraet dich gern zur richtigen Kombination fuer dein Ziel - schreib uns einfach ueber die Kontaktseite.
Common Mistakes
Too much endurance training when your goal is strength. If you want to build muscle but still run long distances every day, you're sabotaging yourself. Adjust your endurance training based on your main goal.
Exhausting endurance training right before leg day. The classic mistake. Separate intense runs from heavy leg exercises.
Ignore recovery. Concurrent training results in a high overall training load. Insufficient sleep and calorie intake increase any interference—regardless of the perfect sequence.
Just running for endurance. If you want to stay strong, supplement or partially replace your running sessions with cycling or rowing.
Frequently Asked Questions
Is it possible to train strength and endurance at the same time?
Yes. Both qualities can be developed simultaneously. Maximum strength and explosive strength develop somewhat more slowly when training volume is high, but research shows that muscle growth remains virtually unaffected.
What should I do first—strength training or cardio?
In a combined workout, prioritize the more important quality first—so for strength goals, do strength training before endurance training. It's best to space the two out by several hours or do them on different days.
Why does running affect strength more than cycling?
Running involves a lot of eccentric stress (deceleration with every step), which causes greater fatigue and damage to the leg muscles. Cycling and rowing are more concentric and therefore cause less interference.
How many endurance workouts are safe?
Two to three moderate-intensity workouts per week have little to no negative impact on strength development for most people. The interference increases with the volume, intensity, and proximity to the strength training sessions.
Does the interference effect also apply to beginners?
Beginners tend to improve in almost every area at the same time at first because their potential is so great. The more trained you become, the more important it is to carefully plan the sequence, timing, and volume of your workouts.
Conclusion
Strength and endurance aren’t opposites, but rather two goals that can be perfectly combined with a little planning. Keep your endurance volume in check, prioritize low-impact exercises, space out your workouts, and prioritize your most important strength goal first—then there will be virtually no interference effect left. When planning your hybrid setup, the Kraftathlet team will be happy to help you choose the right equipment: Contact us now.
Sources: Wilson et al. (2012), “Concurrent Training: A Meta-Analysis,” Journal of Strength and Conditioning Research; Stronger by Science - Research Spotlight: “The Interference Effect”; Hickson (1980), Eur J Appl Physiol; Schumann et al. (2022), Sports Medicine.