Concurrent Training: How Running Affects Strength, Benefits, and Optimization Strategies

Does running affect strength training?

Yes, running can affect strength training, and vice-versa, depending on the volume, intensity, and timing of each modality. While concurrent training can offer significant benefits, it also presents potential challenges due to physiological interference.

The Interference Effect: Understanding the Science

The "interference effect" describes the phenomenon where adaptations from one type of training (e.g., endurance) may impede adaptations from another (e.g., strength or hypertrophy) when performed concurrently. This is a key consideration for athletes and fitness enthusiasts aiming to maximize gains in both areas.

• AMPK vs. mTOR Pathways: Endurance exercise, particularly prolonged or high-intensity running, activates the AMP-activated protein kinase (AMPK) pathway. AMPK is crucial for mitochondrial biogenesis and fat oxidation, but it can also inhibit the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway is a primary driver of muscle protein synthesis (MPS) and hypertrophy, which is the goal of strength training. When AMPK is highly active, it may blunt the anabolic signals needed for optimal muscle growth and strength adaptations.
• Glycogen Depletion: Running, especially long-distance or high-intensity interval training (HIIT), significantly depletes muscle glycogen stores. If strength training is performed immediately after or too close to a demanding run, glycogen availability for the strength session may be compromised, leading to reduced power output, lower training volume, and impaired recovery.
• Residual Fatigue: Both running and strength training induce muscle damage and central nervous system (CNS) fatigue. Performing them too close together or without adequate recovery can lead to accumulated fatigue, impairing performance in subsequent sessions and increasing the risk of overtraining or injury.

Potential Negative Impacts of Concurrent Training

While the interference effect is often debated in terms of its practical significance for general fitness, it can become more pronounced for those aiming for peak performance in either strength or endurance.

• Reduced Strength and Hypertrophy Gains: Studies suggest that concurrent training, especially when endurance exercise is high volume or intensity, may slightly attenuate gains in muscle strength and size compared to strength training alone. This is particularly relevant for individuals whose primary goal is maximal hypertrophy or absolute strength.
• Increased Overtraining Risk: Combining two demanding training modalities without sufficient recovery, proper nutrition, and periodization can lead to overtraining syndrome. Symptoms include persistent fatigue, performance plateaus or declines, mood disturbances, and increased susceptibility to illness.
• Compromised Running Performance: Conversely, very high-volume or intensity strength training, particularly focusing on maximal strength or hypertrophy, can initially lead to increased muscle soreness and fatigue that might negatively impact running performance, especially speed and endurance.

Benefits of Combining Running and Strength Training

Despite the potential for interference, strategically combining running and strength training offers a multitude of benefits for overall health, performance, and body composition.

• Improved Running Economy: Strength training, particularly resistance training focused on lower body strength and power, can significantly improve running economy (the energy cost of running at a given speed). This means you can run faster or longer with less effort.
• Injury Prevention: Strengthening muscles, tendons, and ligaments around joints (knees, ankles, hips) makes them more resilient to the repetitive stress of running. Addressing muscular imbalances through strength training can also correct biomechanical inefficiencies that contribute to injuries.
• Enhanced Body Composition: Combining cardio and resistance training is highly effective for fat loss and maintaining lean muscle mass, leading to a more favorable body composition.
• Increased Bone Density: While running is weight-bearing, strength training provides unique osteogenic (bone-building) stimuli, particularly for bones not maximally loaded during running.
• Overall Fitness and Health: Concurrent training improves both cardiovascular fitness and muscular strength, leading to superior overall health markers, including better blood pressure, insulin sensitivity, and metabolic health.

Strategies for Optimizing Concurrent Training

To minimize the interference effect and maximize adaptations from both running and strength training, strategic planning is essential.

• Prioritization: Clearly define your primary goal. Is it to run a marathon, build maximal strength, or improve general fitness? Your training program should reflect this priority, with the higher priority modality receiving more volume, intensity, and optimal timing.
• Timing and Separation:
  • Separate Sessions: The most effective strategy is to separate running and strength training sessions by at least 6-8 hours, ideally on different days. This allows for recovery and minimizes acute physiological interference.
  • Order of Exercises: If sessions must be combined on the same day, generally perform strength training before running if your priority is strength/hypertrophy. If running performance is paramount, perform running first, but be mindful of fatigue for the subsequent strength session. Avoid high-intensity running immediately before a maximal strength session.
• Training Modality Selection:
  • Running Type: For concurrent training, consider incorporating varied running intensities. Low-intensity steady-state (LISS) running might have less interference than high-intensity interval training (HIIT) when performed close to strength sessions.
  • Strength Type: Focus on compound movements (squats, deadlifts, lunges, presses) that offer the greatest transfer to overall strength and athleticism. For runners, strength endurance or power-focused strength training might be more beneficial than pure hypertrophy training.
• Periodization: Structure your training into phases (e.g., base building, specific preparation, peak, transition). During certain phases, you might emphasize one modality over the other, then shift focus. This prevents overreaching and allows for targeted adaptations.
• Nutrition and Recovery:
  • Adequate Calories: Ensure sufficient caloric intake to fuel both types of training and support recovery.
  • Protein Intake: Prioritize adequate protein intake (e.g., 1.6-2.2 g/kg body weight) to support muscle repair and synthesis.
  • Carbohydrate Timing: Replenish glycogen stores, especially after intense running, to be ready for subsequent strength sessions.
  • Sleep: Prioritize 7-9 hours of quality sleep per night.
• Progressive Overload and Deloads: Apply progressive overload principles to both running and strength training. Incorporate regular deload weeks to manage fatigue and allow for complete recovery and adaptation.

Who Benefits Most from Concurrent Training?

• General Fitness Enthusiasts: For those aiming for overall health, body composition improvements, and functional fitness, concurrent training is highly effective and recommended.
• Endurance Athletes: Strength training is invaluable for runners, cyclists, and triathletes to improve performance, prevent injuries, and maintain lean mass. The focus should be on strength for performance and injury prevention, not necessarily maximal hypertrophy.
• Individuals Seeking Body Composition Changes: The combination of cardiovascular exercise and resistance training is a powerful tool for fat loss while preserving or building muscle.

Key Takeaways for Your Training Program

Running and strength training can coexist harmoniously in a well-planned fitness regimen. The key is intelligent design, respect for recovery, and clear goal setting. While some physiological interference can occur, particularly at elite levels of performance, the overall benefits of combining these modalities for health, injury prevention, and athletic performance far outweigh the minor potential drawbacks for most individuals. Listen to your body, prioritize recovery, and adjust your training as needed to achieve your specific fitness goals.