The decision of whether to lift weights before or after running is a common dilemma for individuals who practice concurrent training. The optimal sequence depends entirely on the primary fitness goal. Performing both activities in the wrong order can lead to the “interference effect,” where strength gains are diminished due to conflicting physiological signals and accumulated fatigue. Understanding the specific demands of each exercise allows you to strategically sequence your workout.
Sequence for Maximizing Strength
The general recommendation for those prioritizing muscle size, maximal strength, or power is to lift before running. Resistance training requires high neuromuscular activation and precise technique, both compromised when the body is fatigued from endurance exercise. Heavy lifting relies on the phosphagen energy system, providing immediate energy for short, intense bursts of effort.
If a run precedes a heavy lifting session, it partially depletes muscle glycogen and causes residual CNS fatigue, reducing the capacity to recruit muscle fibers for maximal force production. This leads to a lower quality strength workout, fewer total repetitions, and a greater risk of poor form. Studies show that performing strength training first leads to greater improvements in lower-body strength.
Starting with resistance training ensures muscles are fresh, allowing for the highest possible weight lifted and the best form, which are the main drivers of strength and hypertrophy gains. Although running after lifting may cause fatigue, the strength-building stimulus has already been delivered. If a run must follow the lift, keeping its intensity and duration moderate minimizes further systemic fatigue and muscle damage.
Sequence for Prioritizing Endurance
For individuals focused on improving running performance—such as increasing mileage or optimizing running economy—the preferred sequence is to run before lifting. Endurance performance relies on fresh energy stores, optimal muscle fiber recruitment for sustained effort, and neuromuscular readiness to maintain form over distance.
Lifting heavy weights, particularly for the lower body, creates muscle micro-tears and causes acute neuromuscular fatigue that can last for hours or days (DOMS). Running while experiencing this fatigue negatively impacts gait and form, compromising the quality of the endurance workout and potentially increasing the risk of overuse injury.
When running is performed first, the athlete can dedicate full capacity to hitting goal paces or distances, ensuring desired cardiovascular adaptations are achieved. The subsequent lifting session should be used as a supplementary tool, focusing on lower-intensity accessory work, injury prevention, or upper-body strength. Research indicates that exercise order does not significantly impact aerobic performance gains, supporting prioritization of the primary endurance session.
Strategies for Combining Both Goals Effectively
Separating Workouts
The most effective strategy for managing concurrent training and minimizing the interference effect is to separate the two types of workouts by a significant recovery period. Ideally, resistance training and running should be performed on different days for complete physiological recovery and adaptation.
If training on the same day is unavoidable, separating the sessions by at least 6 to 8 hours is recommended. This time gap allows molecular signaling pathways related to muscle growth to recover from the endurance activity before the strength session, and vice versa. For instance, a morning run followed by an evening lift provides a sufficient window for energy substrate replenishment and nervous system recovery.
Managing Intensity and Volume
Manipulating the intensity and volume of the non-priority exercise is another practical solution. If the goal is strength, a very light, short jog (less than 20 minutes) can be performed before lifting without major detriment. Alternatively, a low-impact activity like cycling can be used instead of running after the lift. Adequate recovery is also supported by targeted nutrition, ensuring sufficient carbohydrate intake to replenish glycogen stores and protein consumption for muscle repair.