October 27, 2025, 7:01 pm | Read time: 5 minutes
Often, work leaves little time for daily exercise. As a result, many people visit the gym two to three times a week to intensely train specific or multiple body regions. To avoid focusing solely on strength training, some combine their workout with a cardio session. Fitness professor Stephan Geisler discusses whether it’s beneficial to train strength and endurance back-to-back.
Types of Training Trigger Different Cellular Processes
“It’s important to note: The research is not conclusive,” says Stephan Geisler, professor of fitness and health at the IST University in Düsseldorf and head of the fitness trainer program at the German Sport University Cologne. The so-called concurrent training–the combination of strength and endurance training in the same session or on the same day–is said to have a negative or inhibitory effect.
Interference effects are believed to hinder the development of strength and endurance. “This perspective is based on molecular biology,” Geisler explains to FITBOOK. The issue is that the two types of training trigger different processes at the cellular level. Geisler: “Strength training activates a signal transduction pathway, namely protein biosynthesis, which promotes muscle growth. Endurance training, however, activates a completely different pathway that improves mitochondrial capacity. These two types can interfere with each other and potentially lead to inhibition. That’s the origin of the theory,” Geisler tells FITBOOK.
These Mistakes Cause Muscle Growth to Stop
Better Than Stairs? What Makes the StairMaster So Effective
Fitness Professor: Research on Concurrent Training is Divided
According to the expert, some studies show that combining strength and endurance in one session is not optimal. “But there are also studies that have shown it may not have any measurable effect on each other. This, of course, always depends on how such a study is structured and conducted,” says Geisler.
Participate in the big FITBOOK survey!
Concurrent Training Can Affect Strength Adaptation
What effect does the combination of strength and endurance training have on strength adaptation? In 2023, researchers analyzed data from multiple databases involving a total of 1,346 healthy adults aged 18 to 50 years over an intervention period of at least four weeks. They also used results from 59 previous studies on strength, performance, upper and lower body hypertrophy, and/or VO2max.
The findings showed that combining strength and endurance training in one session led to reduced strength adaptation in the lower body for men–but not for women. No differences were observed in upper body strength. Additionally, researchers noted a slight increase in VO2max in both untrained and highly trained individuals. The study was published in “Sports Medicine.”1
Also interesting: How Slow Cardio Works
Increased Proteins and Gene Activity After Combining Strength and Endurance Training
In another small study with eight men, researchers in 2021 examined the molecular reactions in different muscles to consecutive endurance and strength training.2 Participants first completed interval cycling, followed by strength training focusing on the upper body. To compare effects, the men also performed a single strength training session. Blood and small tissue samples from the triceps muscle were taken immediately, 90, and 180 minutes after training.
The analysis of the samples showed increased proteins and gene activities after combining strength and endurance training. These results indicated that cycling and strength sessions did not inhibit each other–quite the opposite: Endurance training seemed to enhance and amplify the expected benefits of strength training. You can read the study details here.
Combining Strength and Endurance Training–What to Consider
As with any training, it’s important to consider your training goals beforehand. Depending on whether you want to improve endurance or strength, you should tailor your workout accordingly. Geisler recommends following the priority principle: “If you’re an endurance athlete, start with endurance training. Then you can add complementary strength exercises, such as stabilization exercises for the core and hips.” According to the fitness professor, you can even do these exercises after every run. “It’s not something that takes another 1.5 hours, overly strains the muscles, or consumes too much energy,” the expert says.
If You Want to Improve Your Strength
If you want to improve your strength, you should start with strength training and can supplement it with a short endurance session. Geisler: “For the fitness enthusiast who makes it to the gym about once or twice, I would advise: First strength training, then moderate endurance training with sufficient nutrients around it.”
If You’re a Runner Doing Strength Training
Despite the divided research, Geisler does not generally advise against double training. However, you must pay attention to intensity, says the fitness professor: “If you’re a runner doing strength training that already tires the muscles significantly, and then immediately follow it with a 10-kilometer run, it will likely diminish your performance in the run.” The strenuous run also means that recovery for the strength training stimulus is not adequately provided.
No Inhibitory Effect Expected If You …
For this reason, the two training forms should be coordinated. “For example, if you do a bit of training in the gym and then spend half an hour on the exercise bike in the fat-burning zone, no inhibitory effect is expected,” Geisler tells FITBOOK.
Role of Nutrition in Concurrent Training
But it’s not just intensity that plays a role in concurrent training; nutrition is also important. “If you consume enough protein before and after strength training and maintain a positive energy balance, endurance training before strength training won’t cause harm.”