A section through the bruise at its midpoint, perpendicular to the skin, appears to have a circular profile, and the resulting bruise volume can be described as a section of a sphere (Mohsenin, 1986). Hence, bruise volume can be calculated for a spherical shape defined below the contact plane (point of maximum defection of the fruit during impact) as shown in Table 2. A simple approximation for bruising at low impact energy is to assume that this occurs at the same depth as the top bruises for the contact plane position estimate. Observation of bruise shapes suggests that this is a reasonable approximation (Table 2). The section of a sphere can thus also be calculated, based on the bruise thickness.