Falls are a part of the motor actions performed by practitioners of some physical and sports disciplines (although in these cases, the falls are intentional). They are found in well-known sports such as parkour, football (in the actions of goalkeepers), volleyball (receptions in a plank position or falls in backward movements), and, for example, athletics (high jump and long jump).

Among these disciplines, there is one that places special emphasis on its teaching as part of the motor skills of its practitioners. Thabot (1999, p.70) explains that, in the discipline of judo, the individual (in this case, the defender) can fall if the attacker's action is carried out correctly. Therefore, it is advisable to learn how to fall, even if the goal of the match is to avoid it.

In the practice of this sport, the actions of controlling the falls that may occur in its practice are called "ukemis" and are part of the technical-tactical elements that make it up. These are understood as the essential and indispensable parts of the technical-tactical action, which, when interconnected in a biomechanical training system, form the basis of the motor structure of the technique and the practice in judo (Miralles, 1995). We can understand these actions as ways to fall without suffering harm, in other words, specific work to learn to fall in a controlled manner, minimizing the damage caused by the fall.

Authors such as Uzawa (1981, p.28) and Lasserre (1975, p.28) emphasize the transcendental importance of these actions, with the latter stating that they are "the first thing that should be learned in the practice of this discipline." Carratalà (2000, p.51) expresses that they represent "the most rational method of cushioning the impact against the surface on which the fall occurs, in the case of judo, the tatami."

Although with slight variations, there is broad consensus in specialized literature on categorizing these "ukemis" according to the action performed as "ushiro ukemi" or backward fall, "yoko ukemi" or lateral fall, "mae ukemi" or forward fall, and "mae mawari ukemi" or rolled forward fall. In the case of the latter, learning is done both on the right and left sides.

Taira (2009, p.112) points out that to cushion falls, the action of the arms and the body's rotational movement are essential.

a) Softening the Impact with the Arms: Striking with the arms significantly reduces the force with which the rest of the body hits the ground. This is because the arms oppose the downward force, creating an upward force when struck. Therefore, the stronger the impact with the hands against the ground, the less momentum the body will have when hitting the ground, reducing the risk of injury. Research conducted by different authors supports this assertion. Hashimoto et al. (2015) demonstrated that the impulsive force generated by hand contact can greatly contribute to reducing the impulsive force on the head during a fall. Koshida et al. (2014) suggest that hand contact may be associated with decelerating the head during backward falls in judo. In theory, hand contact would decrease the momentum of the backward fall and dissipate tension applied to the body.

In the case of the Safe Fall-Safe Schools program, a significant adaptation to hand striking is proposed because it is crucial to understand the context where an unintended fall can occur. When falling on the street, it is vital to avoid direct head impact with objects such as curbs, rocks, street furniture, cars, etc. To achieve this, we propose and work with exercises where the primary function of the hands is to protect the head, acting like a "helmet," to prevent possible impact with objects found in the path of an unintended fall. By protecting the head with the hands, we achieve a dual function: preventing direct impact and avoiding placing the hands on the ground.

b) Softening the Impact through Rotational Movement: It is important to perform falls by rolling on the surface on which contact is made, as if it were a sphere. Falling with a tense and fully extended body leads to a strong impact, with vibrations transmitted to the head or internal organs. Conversely, rolling over the body significantly reduces the resonance effect, as the relaxed body absorbs the vibrations and transforms the falling force into rotational force, allowing the body to rotate. Groen et al. (2010) explain that one of the most important characteristics of martial arts falling techniques is the rolling movement and head protection. Trunk and neck flexion also prevent the head from impacting the ground. It has been shown that a squat response reduces impact velocity by up to 18% in backward falls, but its effectiveness depends on the phase of descent (Robinovitch et al., 2004) and available joint muscle strength (Sandler & Robinovitch, 2001). By reducing the speed and acceleration that affect the head during judo practice, the angular momentum of the head and peripheral neck moment decreases, resulting in reduced head injuries (Gennarelli & Thibault, 1982).

From a methodological perspective, the learning of "ukemis" is recommended in three stages. The process begins from a seated position, then slightly raising the center of gravity to squatting, and finally, they are performed in an upright position (Lasserre, 1975, p.29). In the case of the Safe Fall-Safe Schools program, we add a fourth level of falling, suspended falls. This progression can be done individually, with a partner, assisted, resisted, without equipment, and with equipment.

It is essential to consider Miralles' (1995) distinction between "falling" and "being projected," particularly regarding the difference in kinetic energy involved in each. When one falls by themselves, the kinetic energy generated is lower. Conversely, when "being projected," the kinetic energy is higher due to the combined mass of the person being projected and the muscular force exerted by the projecting person, along with their displacement in the direction of the projection.

Here are some of the principles that should be considered in the study of falls, according to Miralles' (1995):

If the impact of the fall is distributed over a large surface, the force's magnitude on any specific part of the body is reduced.

The danger of falls greatly depends on the deformity and compressibility of the impact surface.

The severity of trauma resulting from a fall depends mainly on the anatomical part that receives the impact.

In judo practice, falling is generally considered an inherent aspect of the activity, primarily aimed at ensuring the safety of the practitioner who is destined to be projected. However, the real scope and utility of this concept should be seen more broadly, emphasizing its educational resources and its importance as a fundamental element (Kolychkine, 1989, p.41). This author adds that mastering falls allows offering certain benefits to the projected athlete, among which we highlight "protection against accidents." We understand that this protection is initially perceived in the specific sports practice but extends beyond it, into real life.

It is true that judo practice takes place on a specialized surface that, among other purposes, helps minimize injuries due to impact in throwing actions that practitioners undergo. However, this competency can be useful in various everyday situations. Research (Mroczkowski & Taiar, 2023) suggests the advisability of introducing fall learning into regular physical education to reduce the harmful effects of falls and practice them throughout life as part of personal safety.