Scientific rambling
In these days, the heaven and earth in the north were covered with a heavy snowfall, covered in silver, like a pure picture. However, although this snowy scene is beautiful, it also brings a lot of trouble. Especially on the road, the snow makes the road slippery, making it easy for people to fall when walking. A minor fall may be excruciatingly painful, but in severe cases, there is a risk of fractures. Among these fractures, arm fractures are particularly common, followed by leg and hip fractures.
As a result, there are always some "experts" who give the so-called "correct fall posture", telling us that we should try to avoid landing on the ground with elbows, and instead choose to land on the ground with thick flesh such as buttocks, between legs, shoulders or back, and need to cover our heads with both arms and roll with the trend. However, today we will take a look at it from a biomechanical point of view, are these so-called "correct fall postures" really as effective as the "experts" say?
First of all, we must recognize that there is not enough time to react and adjust at the moment of the fall. Therefore, subconsciously, people tend to use their hands and feet to support their bodies first. This means that we can't control the posture of the body at all, and choose to let ** land on the ground first. 
Second, let's consider the question again: does a person have enough time to strike the so-called correct posture before falling? Obviously, this is unlikely. Even if we had time to prepare, the possible results would be very different from what the "experts" expected. 
The human body is a complex structure with a multi-member, multi-articulating locomotor system consisting of a torso, skull, and limbs. The musculoskeletal system of our limbs forms important segmental motor units, which resist external forces and cushion vibration absorption like springs connected together. Therefore, whether in daily life or in extreme sports, people will try to let the limbs hit the ground first, so as to use the musculoskeletal system of the limbs to cushion and absorb vibration, and avoid impact and damage to the trunk and head. 
It can be seen that humans naturally formed a falling posture on all fours during the evolutionary process, which is to better protect the core organs from injury. So, let's understand this problem from the perspective of bionics. We've all heard stories of geckos, lizards, and other animals that "break their tails to survive". Why can a "broken tail" "survive"? The answer lies in the fact that the end tissues of the body are not fatal. Discarding the "leftovers" at the end of the body can better protect the vital organs of the core area. This is the result of the continuous adaptation and evolution of species in their natural environment. Human beings have evolved in the same way, and it is not difficult to understand the reason. Therefore, from the point of view of medical biomechanics, the natural falling posture should be on all fours when slipping and falling on a snowy road. While the arm is important, the nuclear heart apparatus is even more critical. If the arm hits the ground first, we can also use the musculoskeletal system of the limb to cushion vibration absorption, thereby reducing the impact damage to the nuclear heart apparatus. Then the question arises: do you think that falling in the way of the "experts" will be more serious? Or will it be worse to fall in the same way as medical biomechanics?