Shock absorber
The most important function of shock absorbing mat is to support the instinctive or learned behaviour during the fall. People are trying to land on legs with the help of hands if it's necessary or possible. Human instinct is developed for falls on hard surface. Locally very deformable surface can disturb instinctive action and cause increased risk for injuries like ankle sprains.
In case of controlled falls from reasonably low heights relatively hard shock absorbing mats are a good solution. At reasonably slow speed they also offer acceptable low deceleration in case of the head impact. Head deceleration during impact is normaly the most important cryteria.
These mats can be used for higher falls in case of trained users who can redirect their vertical movenment into horizontal. This is however possible only in case of controllable fall from a reasonable height!