Running: Its Contribution to Strength, Limitations, and the Importance of Resistance Training

Is running a strength activity?

While running undeniably demands and utilizes muscular strength, particularly in the lower body and core, it is primarily an endurance activity and not a standalone strength-building program in the same vein as resistance training.

Defining Strength in Exercise Science

To understand running's relationship with strength, it's crucial to first define what "strength" means within the context of exercise science. Strength refers to the ability of a muscle or muscle group to exert force against resistance. This encompasses several facets:

• Maximal Strength: The maximum force a muscle can generate in a single contraction.
• Relative Strength: Maximal strength relative to body weight.
• Muscular Endurance: The ability of a muscle or muscle group to sustain repeated contractions or maintain a contraction over time.
• Power: The rate at which work is performed, combining strength and speed (Force x Velocity).
• Isometric Strength: Force produced without a change in muscle length (e.g., holding a plank).
• Concentric Strength: Force produced as the muscle shortens (e.g., lifting a weight).
• Eccentric Strength: Force produced as the muscle lengthens under tension (e.g., lowering a weight slowly).

The Demands of Running: A Biomechanical Perspective

Running is a complex, cyclical activity that places significant demands on the musculoskeletal system. Each stride involves a precise interplay of muscle contractions, relying heavily on various forms of strength:

• Shock Absorption (Eccentric Strength): As the foot strikes the ground, the quadriceps, hamstrings, and calf muscles (gastrocnemius and soleus) undergo eccentric contractions to absorb impact forces, control deceleration, and prevent collapse. This eccentric loading is particularly pronounced during downhill running.
• Stability and Control (Isometric Strength): Throughout the stance phase, the core muscles (abdominals, obliques, erector spinae), gluteal muscles (gluteus medius and minimus for hip abduction and stabilization), and hip flexors work isometrically to stabilize the pelvis and trunk, maintaining upright posture and preventing excessive lateral movement.
• Propulsion (Concentric Strength): The push-off phase relies on concentric contractions of the gluteus maximus, hamstrings, and calf muscles to extend the hip, knee, and ankle, propelling the body forward.
• Muscular Endurance: Given the repetitive nature of running, the primary demand on the working muscles is to sustain these contractions for extended periods. This is a clear measure of muscular endurance.
• Power (Sprinting/Uphill): When running at higher speeds, such as during sprints or uphill climbs, the demand shifts towards power production, requiring muscles to generate force rapidly.

Running's Contribution to Strength

Based on its biomechanical demands, running can contribute to certain aspects of strength:

• Enhanced Muscular Endurance: This is arguably running's strongest contribution to strength. The continuous, repetitive nature of the activity significantly improves the endurance capacity of the primary running muscles.
• Improved Eccentric Strength: The consistent eccentric loading during ground contact, especially in the quadriceps and calves, can lead to adaptations that improve the muscles' ability to absorb force and tolerate stress. This is crucial for injury prevention.
• Increased Core and Hip Stabilizer Endurance: The isometric demands on the core and hip abductors/extensors strengthen their ability to maintain stability over long durations.
• Bone Density Benefits: As a weight-bearing activity, running stimulates bone remodeling, leading to increased bone mineral density, particularly in the lower extremities.
• Some Power Development: Incorporating hill sprints or interval training can stimulate adaptations that improve lower body power, making muscles more efficient at generating force quickly.

Where Running Falls Short as a Standalone Strength Program

Despite these contributions, running alone is insufficient for comprehensive strength development for several key reasons:

• Limited Hypertrophy (Muscle Growth): Running is typically a high-repetition, low-resistance activity. While it can improve muscular endurance, it does not provide the sufficient mechanical tension and progressive overload necessary to stimulate significant muscle hypertrophy (growth) or maximal strength gains.
• Specificity of Training (SAID Principle): The Specific Adaptation to Imposed Demands (SAID) principle states that the body adapts specifically to the demands placed upon it. Running makes you better at running. It does not effectively train the full range of motion or provide the varied resistance needed to build balanced, maximal strength across all muscle groups.
• Neglects Upper Body and Non-Locomotor Muscles: Running places minimal direct demand on the upper body (beyond arm swing) and many other muscle groups crucial for overall functional strength, such as the back, chest, and posterior chain muscles that aren't prime movers in running.
• Difficulty in Progressive Overload: While you can increase distance, speed, or incline, it's challenging to progressively overload muscles in the same targeted way as resistance training (e.g., adding 5kg to a squat).
• Unilateral Focus: Running is a unilateral activity, working one leg at a time. While this is excellent for single-leg stability, it doesn't adequately train bilateral strength or address potential imbalances that can arise from repetitive, single-plane movements.

The Synergy: Integrating Strength Training for Runners

Given the limitations of running as a sole strength builder, incorporating dedicated resistance training is not just beneficial, but essential for runners. This synergistic approach leads to:

• Injury Prevention: Stronger muscles and connective tissues are more resilient to the repetitive stresses of running, reducing the risk of common injuries like IT band syndrome, runner's knee, and shin splints.
• Improved Performance: Enhanced maximal strength and power translate to a more efficient stride, better uphill performance, a stronger finish kick, and improved running economy.
• Correcting Imbalances: Targeted strength exercises can address muscle imbalances that often develop in runners, promoting better biomechanics and reducing injury risk.
• Increased Bone Density: While running contributes, a well-rounded strength program further enhances bone health.
• Overall Health and Longevity: A balanced strength program contributes to overall physical robustness, functional capacity in daily life, and long-term athletic participation.

Recommended Strength Training for Runners:

• Compound Movements: Squats, deadlifts (or RDLs), lunges, step-ups to build foundational lower body and core strength.
• Single-Leg Exercises: Pistol squats, single-leg RDLs, Bulgarian split squats to enhance unilateral strength and stability.
• Core Stability: Planks, bird-dog, anti-rotation presses to build a strong and resilient core.
• Glute Activation: Glute bridges, band walks to ensure the glutes are firing effectively.
• Plyometrics: Box jumps, bounds, skipping drills to develop power and elasticity.

Key Takeaways for Runners

In conclusion, while running is a highly effective cardiovascular and muscular endurance activity that utilizes and develops specific aspects of strength (particularly eccentric and endurance strength in the lower body and core), it is not a comprehensive strength-building exercise in itself. For optimal performance, injury prevention, and long-term athletic health, runners should view dedicated resistance training as a vital complement to their running regimen, rather than an optional extra. By combining the endurance benefits of running with the targeted strength development of resistance training, athletes can unlock their full potential and enjoy a more resilient, powerful, and sustainable running journey.