when the life expectancy was 40 years, Edward Payson Weston (1939-1929) walked 725 kilometers from Boston to Washington DC in 10 days and 10 hours. Then I participate in six -day races at Madison Square Garden in New York and in the London Agricultural Hall. At 71 he was the first to cross the United States from Los Angeles to New York City, a total of 5794 kilometers in 88 days, averaging 66 kilometers/day. At 80 he walked 40 kilometers/day (equivalent to a marathon). In 1909 he walked 100 consecutive days, touring 6,437 kilometers from New York to San Francisco. Weston, in full health, died at 90 in a traffic accident.
While there are obsessive features in Weston’s activities, it is also true that the human being was always a nomad in constant movement. In fact, the central part of any training is regularly repeated physical exercise, and planned to stress the physiological systems that limit performance.
The term “walk” means having both feet in contact with the surface at the same time, while “running” means having only one foot, or none, on the surface at a given time, there is a flight phase. Therefore, the time or flight phase corresponds to the amount of time that is passed without contact with the ground. This allows the speed to be increased considerably above the one to walk.
The flight phase raises the center of mass of the body, and then falling allowing the next step. This movement consumes 20% of total energy expenditure. The rupture point between walking and running ranges between 8 and 9 km/hour. From there, running becomes cheaper than walking.
“Movement economy” is oxygen consumption during stable exercise, “mechanical efficiency” evaluates the relationship between work done and the energy sold, and the “total energy expenditure” includes the energy sold in activity and rest.
Walking represents its main daily physical activity. On a flat surface, energy expenditure (kcal/minute) increases as speed increases. In this way, walking 6.4 kilometers/hour you spend just over 3 kcal/minute and 12.8 km/hour somewhat less than 9 kcal/minute.
As the speed increases energy expenditure also increases producing major changes at larger speeds. In addition, already measure that the slope of the surface increases, the energy expended also increases considerably.
There is a linear relationship between speed when walking and oxygen consumption. Walking on dry sand requires twice as much energy as on a firm surface. This is because the sand yields to the footprint hindering the foot-soil contact and the calf muscles to apply greater strength to compensate for the sliding. Walking on soft snow triples energy expenditure compared to walking on a flat and firm surface.
Bringing weights in the ankles or feet requires considerably greater energy expenditure than wearing the same weight in the torso. A weight equivalent to 1.5% of the body mass over the ankles increases energy expenditure by walking by 8%, considerably more than with the same weight placed on the torso.
The type of muscle fiber also influences. The walkers who exhibit the cheapest patterns have higher percentages of slow contraction fibers (type I/oxidative) in the lower limbs. When walking, these fibers produce greater mechanical efficacy than rapid contraction fibers (type II/anaerobic) rapid contraction.
As for heart disease, running reduces risk by 4.5%, while walking by 9.3%. Therefore, and in all cases, walking is significantly more beneficial than running. And, in addition, it produces less wear and risk of injuries.
The beneficial physiological effects derived from walking regularly are the following: 1.- Descent of blood pressure; 2.- Descent of triglycerides, 3.- HDL cholesterol elevation (good); 4. Decrease in LDL cholesterol (bad); 5.- Optimization of body composition; 6.- Better glucose tolerance; 7.- Better general muscle tone derived from the vibration produced in each step; and 8.- Positive psychological effects, such as best adaptation to stress, reduction of anxiety and depression, and a clear improvement in mood, among others.
Some of these effects are directly from physical training, while others do it for induced modifications on cardiovascular risk factors.
Today there are multiple telephone applications (apps) for walkers. Such programs are easy to use and very beneficial to control both the volume (quantity) and the intensity (quality) of the sessions.
Guillermo A. Laus’s colleces
Doctor of Medicine and Surgery
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