Running posture is a crucial element that can impact running efficiency and economy. Recent research has concluded that running with an increased forward postural lean negatively impacts running economy, leading to higher energy expenditure. Here’s an in-depth look at the findings and their implications for runners.
The Study and Its Findings
Researchers investigated how different degrees of postural lean, both moderate and maximal, either from the ankle or torso, affected running economy. The key findings were:
Increased Energy Usage: Runners who increased to a high degree of forward lean used 8% more energy compared to when they ran with a moderate or upright posture. This increase in energy usage was consistent regardless of whether the lean originated from the ankle or the torso.
Stride and Stance Adjustments: Increased forward lean caused a 6% decrease in stride length, a 7% increase in stride frequency, and longer stance times. Overstride increased by 28% from normal to high trunk flexion angles.
Muscle Activation and Moments: Greater trunk flexion led to a 70% INCREASE in hip extensor moments, but a DECREASE in knee extensor and ankle plantarflexor moments by 22% and 14%, respectively. The rate of loading increased by 29%, and vertical ground reaction force impact transients increased by 20%. These findings support previous research by Teng (2014) and Warrener (2014).
Understanding the Mechanisms
Increased Muscle Activation: Running with a forward lean increases hip and knee flexion when the foot is on the ground. This means the hip extensor muscles, particularly the gluteus maximus and biceps femoris, have to work harder to counteract the ground reaction force, leading to greater muscle activation.
Demand on Less Efficient Muscles: The gluteus maximus, a large muscle in the hip, is less efficient at generating force compared to smaller muscles in the ankle. The increased reliance on the gluteus maximus with a forward lean contributes to the decreased running economy.
Recommendations for Runners
🏅Utilize a moderate Lean: To optimise running efficiency, runners may benefit from maintaining a more upright or moderately forward postural lean. Our recommendation is to lean from the ankles & not excessively from the hips
⚖️An increase in trunk lean can reduce load on the knee, but does so at the expense of increased demand on the hip extensors. IF wanting to decrease knee loads, there are often other strategies that can be used such as increasing cadence,
By refining their running posture, runners can enhance their efficiency and better distribute forces throughout their bodies, optimizing performance and reducing the risk of injury.
📚References
Carson, N. M., et al. (2024). "The effect of forward postural lean on running economy, kinematics, and muscle activation." PLoS One 19(5): e0302249.
Teng, H. L. and C. M. Powers (2014). "Sagittal Plane Trunk Posture Influences Patellofemoral Joint Stress During Running." J Orthop Sports Phys Ther: 1-31.
Teng, H. L. and C. M. Powers (2014). "Influence of Trunk Posture on Lower Extremity Energetics during Running." Med Sci Sports Exerc.
Warrener, A., et al. (2021). "The effect of trunk flexion angle on lower limb mechanics during running." Hum Mov Sci 78: 102817.