Walking is a complex act of human movement. It involves an interplay of our nervous, musculoskeletal, and sensory systems working to propel us forward. This action is a sequence of balance, coordination, and force generation. Understanding the mechanics of how we walk offers insights into our physical capabilities across the lifespan.
What is Double Support Time?
Double support time refers to the brief period during walking when both feet are simultaneously in contact with the ground. This phase occurs twice within a single gait cycle: once when the back foot is pushing off and the front foot is landing, and again as the front foot prepares to push off while the back foot lands. It represents a brief moment of increased stability, contrasting with the single support phase where only one foot is on the ground.
During the gait cycle, the stance phase accounts for approximately 60% of the total cycle, while the swing phase makes up the remaining 40%. This period of bilateral contact allows for better control of the body’s center of mass, contributing to overall balance and reducing the risk of losing equilibrium.
Double Support Time in Childhood Development
The journey of walking begins with a high percentage of double support time in toddlers. When children first learn to walk, often around 12 months of age, their gait is characterized by a wide base of support and short, quick steps. This wide stance and increased time with both feet on the ground provide greater stability as they develop their balance and coordination.
As a child’s gait matures, establishing a more adult-like pattern around 3 to 7 years of age, the percentage of double support time gradually decreases. This reduction reflects improvements in muscle strength, balance, and proprioception—the body’s awareness of its position in space. The shift towards less double support and more single support indicates a more efficient and confident walking pattern.
Double Support Time in Adulthood
In healthy adults, double support time is a small and stable percentage of the gait cycle. It averages around 20% of the total gait cycle, with some sources indicating a range of 28% to 40% of the stance phase. This lower percentage signifies an efficient and balanced gait, where the body spends minimal time with both feet on the ground while maintaining forward momentum.
Factors like walking speed can influence this parameter. As walking speed increases, double support time tends to decrease. Conversely, walking slower or on uneven terrain can lead to an increase in double support time as a compensatory mechanism for stability.
Double Support Time and Aging
As individuals age, particularly after 70 years, double support time increases. This change is a common age-related adaptation in gait, with healthy older adults spending 26% or more of their gait cycle in double support, compared to 18% in young adults. This increase provides a wider base of support and more time for the body to control its center of mass, thereby enhancing stability.
The reasons for this increase are multifactorial, including natural declines in muscle strength, particularly in the calf muscles, and changes in balance and sensory perception. Older adults may also increase their double support time when walking on uneven surfaces, if they have impaired balance, or if they experience a fear of falling. This cautious gait pattern, while providing stability, can also lead to a shorter stride length and reduced walking speed, impacting overall mobility and potentially indicating changes in health or increased fall risk.