{HEAD ~ a) an elastic support} exhibiting a resilience of {TAIL ~ at least 80%}; and 
{ HEAD ~ a ) an elastic support } exhibiting a resilience of { TAIL ~ at least 80 % } ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH