Sand makes it harder to walk or run. Nevertheless, why?

For some, nothing compares to a leisurely stroll on a sandy beach. Yet, it is undeniable that beach travel is more difficult and slower than on a road or sidewalk. But why is walking on sand so difficult?

“The trouble with sand is that it is soft; you sink in’ with each step,” Paola Zamparo, a biomechanics researcher at the University of Verona in Italy, wrote in an email to Live Science. This causes you to expend 2.1 to 2.7 times more energy every step, according to research published in the Journal of Experimental Biology (opens in new tab).

In addition to the fact that sand deforms underfoot, the unevenness of beaches and sand dunes makes traversing them difficult. “On the sand, the base of support is likewise uneven, and moving on uneven terrain demands greater energy,” explained Zamparo. This requires your body to make minor, sometimes unconscious, modifications to your stride, therefore working muscles — particularly in the ankle and foot — that would otherwise be at rest. According to Barbara Grant, a biomechanics expert at the University of Liverpool in the United Kingdom, these muscles “will need to actively contract to guarantee stability.” A similar effect occurs while hiking on a trail with many rocks and roots; even if you walk at a fair speed, you will tire out more quickly than if you were strolling on a sidewalk.

According to a 2022 research published in the Journal of the Royal Society Interface(opens in a new tab), humans walk differently on sand than they do on hard surfaces. Grant and her colleagues at the University of Liverpool evaluated how people walked on foam vs solid surfaces by monitoring the forces under their feet and the amount of oxygen required by each individual. They discovered that walking on soft surfaces, such as sand, mud, and snow, prompted individuals to take longer steps and perform greater hip and knee motions, which use more energy than walking on a solid surface.

Scientists have discovered, to their surprise, that jogging on sand minimizes the discrepancy in energy consumption. Jogging on a beach consumes around 1.6% more energy than running on a level, solid terrain. Yet, because running (at least at a rapid speed) is more energy-intensive than walking, dashing over sand would still require significantly more energy than strolling on it.

Yet seasoned beach walkers know there is a technique to make walking on sand easier: just add water.

“When sand is moist, it becomes more compact, and walking on it more closely resembles walking on hard soil,” explained Zaparo. In other words, it is considerably simpler to traverse a beach by strolling along the shoreline, where the waves are constantly ebbing and flowing. But, this is a delicate balance; to much water might make the sand soupy and soft once more.

If water is unavailable, there is another technique to make negotiating sand simpler, according to Grant of Live Science: “Expand your surface area.” This might be achieved by wearing shoes or altering your stride to land more flat-footedly than usual.

There are advantages to exercising on the sand, despite the fact that it is more challenging. “In sand, the impact pressures are less than on the solid ground,” stated Zamparo. According to research, walking or jogging on sand is far less taxing on the joints and muscles than on a hard surface like concrete. Research indicates that sand is a superior surface for helping athletes recover from exercises and rehabilitating individuals. Several elite sportsmen, like NBA superstar Russell Westbrook, include sand training in their exercise routines. Nonetheless, Grant advised exercising with sand with caution. “Due to the fragility of the sand, the possibility of tripping or falling is increased,” she stated.

Remember this the next time you take a leisurely stroll down the sand: You’re actually working extra hard – all the more reason to enjoy a margarita on your beach trip.

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