Cardio vs Strength Order
Runner's World reveals trainers recommend tailoring the sequence to your primary fitness goal — those seeking endurance should prioritize running before weights, while strength gains are maximized by starting with resistance training. They also explore balancing long and short runs to build both endurance and speed.
The "interference effect" is a key concept in concurrent training, describing how endurance exercise can limit strength and muscle gains. This phenomenon is rooted in competing molecular pathways within the muscles. Resistance training activates the mTOR pathway, which is crucial for muscle protein synthesis, while endurance exercise stimulates the AMPK pathway, which can inhibit mTOR. Performing cardio before lifting weights can deplete glycogen stores, which are the primary fuel source for high-intensity strength training. This pre-fatigue can reduce the number of repetitions you can perform and may compromise proper form, increasing the risk of injury. Strength gains, particularly for lower-body dynamic strength, have been shown to be superior when resistance training is performed before endurance work. The order of your workout also triggers different hormonal responses. Doing cardio before a strength session can lead to depressed levels of anabolic hormones like testosterone and growth hormone for up to 48 hours post-exercise, potentially hindering muscle recovery and growth. Conversely, cardio produces a significantly larger amount of FGF21, a hormone with positive effects on metabolism, compared to strength training. For those looking to maximize both strength and endurance, separating the two types of workouts is often recommended. A recovery period of at least 3 to 6 hours between sessions can minimize the interference effect. If they must be done in the same session, performing strength training first is generally advised to optimize muscle-building signals and energy for lifting.
