CaliforniaCarlson,
Listed below are some of the criteria for IAAF synthetic tracks which are relevant to this discussion (IMHO)
"2.4 Shock Absorption
Requirements
The dynamic interaction between the athlete and the surface is significant to the
performance and safety of the athlete. Therefore the ability of the surface to reduce
force (absorb energy / shock) is important. The shock absorption shall be between 35%
and 50%, at any surface temperature between 10°C and 40°C. If, at the time of
measurement, the temperature of the surface is outside this range, it shall be
permissible for the results obtained to be corrected for temperature by interpolation
from a graph of shock absorption against temperature for the precise surfacing system
installed previously obtained by laboratory testing. "
"2.5 Vertical Deformation
Requirements
The dynamic interaction between the athlete and the surface is significant to the
performance and safety of the athlete. Therefore the ability of the surface to deform
under load is important. Too high a deformation can affect the safety of the athlete
through instability of the foot, while the inability of the surface to deform can cause
IAAF Track and Runway Synthetic Surface Testing Specifications
June 2016 9
injuries due to impact forces. The vertical deformation shall be between 0.6mm and
2.5mm, at any surface temperature between 10°C and 40°C. If, at the time of
measurement, the temperature of the surface is outside this range, it shall be
permissible for the results obtained to be corrected for temperature by interpolation
from a graph of vertical deformation against temperature for the precise surfacing
system installed previously obtained by laboratory testing."
Can be found in the document "Track and Runway Synthetic Surface Testing Specifications" at