JMCx4
Censorship is the Sincerest Form of Flattery
Generally speaking, a rigid material would transfer more energy from an impact than a pliable material would. The challenge as a consumer (and concerned parent/guardian or adult user) is that manufacturers keep their product designs & performance proprietary for competitive reasons. So you may have to purchase more than one product and decide on your own which one will provide the better protection for the child (or adult).