30 Seconds SummaryResearch Spotlight: The interference effect is getting less scary by the day
- Concurrent training, which combines strength and endurance workouts, has long been feared for its interference effect - a potential reduction in strength, power, and muscle gains.
- Initial research, like the 1980 Hickson study, highlighted significant negative impacts of concurrent training on strength gains compared to resistance training alone.
- Subsequent studies and meta-analyses over the years, including a notable 2021 review, have shown that the interference effect is less significant than previously thought, especially if resistance and endurance sessions are separated, and/or if trainees are less experienced.
- A recent meta-analysis by Schumann and colleagues analyzed 43 studies and found no significant differences in strength gains and muscle hypertrophy between concurrent training and resistance-only training; however, a reduction in explosive power gains was noted.
- Factors such as the type of endurance training, frequency, age of participants, and training status did not significantly alter the results, indicating a generalized minimal interference effect for strength and hypertrophy.
- Despite less concern over the interference effect, it's still wise to consider individual recovery capacity, training volume, and training intensity, especially if targeting maximal strength gains or when working under high stress and recovery limitations.
- There is evidence suggesting significant interference in explosive strength and power output with concurrent training, making it a specific concern for athletes in sports requiring these abilities.
Stronger By Science
Greg Nuckols
