In the lively Paris Olympic Games, we also saw many glorious moments of Olympic athletes winning glory for the country.
However, during the swimming competition, we saw a strange scene---- even in Paris, which is not cold in July, most of the swimmers enter the stadium wearing down jackets.
It's hot enough, so why wear a down jacket?
In fact, in many sports, swimmers' appearances are particularly eye-catching. Their behavior of wearing down jackets before the game may seem unrelated to regular warmth, but in fact, there is a deep scientific principle and practical need behind it.
First, maintain muscle temperature
In a big competition like the Olympics, every little detail can affect an athlete's performance.
Swimmers warm up their muscles before the race, and wearing a down jacket after the warm-up helps to quickly recover their body temperature and prevent excessive heat loss, thus preventing the body temperature from dropping too quickly while waiting for the start of the race.
In addition, keeping your body hot helps keep your muscles elastic and reflexes, which is especially critical for swimmers who want to reduce resistance and increase speed in the water as much as possible.
Second, prevent environmental impacts
Usually the ambient temperature in the swimming pool is usually lower than the water temperature, and the warmth of the down jacket can prevent athletes from being adversely affected by the cold environment while waiting for the competition.
Even when competing outdoors or in colder climates, down jackets provide the necessary warmth to help athletes stay in top shape.
Third, maintain cardiopulmonary function
After the warm-up, the athlete's cardiorespiratory function is mobilized, and the warmth of the down jacket helps to maintain this condition, keeping the athlete's breathing and heartbeat at an optimal level during the competition.
Fourth, improve psychological comfort
The waiting time before a competition can be extremely stressful for athletes, and keeping the body warm can bring comfort to athletes, thereby reducing their anxiety and allowing them to be more focused and confident in the competition.
In addition to swimming, athletes in other sports such as weightlifting also need to wear down jackets to keep their bodies warm before competitions, which will help them perform at their best in the following competitions.
Pool water at the right temperature is both a "radiator" and an "accelerator"
The water temperature in the pool not only helps regulate body temperature, but also affects the speed at which you can swim.
Studies have shown that spending as little as four minutes in water at 12 degrees Celsius consumes the same amount of calories as an entire hour of activity on land at the same temperature.
This is because when swimming in water, the body produces a lot of heat in order to adapt to the environment, and the metabolic rate also rises, resulting in an increase in body temperature.
At this time, if the temperature of the pool water is lower than the human body temperature, it can effectively remove excess heat and make people feel cool and comfortable.
According to the China Meteorological Agency, there is a link between water temperature and speed:
The internal friction coefficient of the fluid is 1.83 at 0°C, drops to 1.03 at 20°C, and drops to 0.84 at 30°C. At the same time, the density of water varies with temperature: 1.0 g/cm3 at 0°C and 0.997 g/cm3 at 25°C.
Considering that the density of the human body when inhaling is between 0.94 g/cm3 and 0.96 g/cm3, it can be seen that the buoyancy and resistance of the human body in the water will vary under different water temperatures.
These data show that within a certain temperature range, the higher the water temperature, the smaller the internal friction coefficient of the water, which means that the water will have less resistance to the human body, so that it can swim more easily.
At a water temperature of 25°C, the internal friction of water is about 30% less than at 10°C. However, when the water temperature exceeds 24°C to 28°C, the reduced friction effect is offset by the change in density.
From the above analysis, we learned that the right temperature of the pool water not only helps to maintain the swimmer's body temperature, but also increases the swimming speed by reducing the resistance of the water. Therefore, the regulation of water temperature is essential for swimming.
Is it necessary for us ordinary people to wear down jackets when going swimming?
For ordinary people, you don't have to wear a down jacket when swimming indoors, and you can spare clothes to keep warm when swimming outdoors or in winter, but not necessarily a down jacket, and a thicker towel quilt can also be used.
These suggestions provide people with a professional guide to keeping warm in swimming, so that people can make reasonable choices according to their actual situation.
Wearing a down jacket before a swimmer takes the field is a science- and practice-based choice designed to help athletes perform at their best in competition.
Down jackets are ideal for swimmers by maintaining body temperature, protecting against environmental influences, maintaining cardiorespiratory fitness, improving psychological comfort, facilitating warm-ups, meeting competitive needs, and taking personalization into account.