08/25/2026
Ground Contact Points (GCP) and Pressure Releases. Many trackers discuss “pressure releases” as how the foot places/impacts and releases pressure/weight from the substrate. We must look beyond that into the types, and why they exist and vary between quarry. What is from developmental programming and what is current based upon internal and external stimuli and how do they influence the gait footfall sequence?
Indicator and Fluctuating Pressure Releases:
IPR–This GCP category indicates quarry identity and/or psychomotor behavioral programming condition. For instance, finding a class 1 print would be an IPR that the spoor was human. Further detail as to the condition of the human spoor would indicate that the human was male or female, that they had a leg injury, that they are left or right eye dominant, or perhaps that the human has a phobia (fear), is out of control, is very calculating, etc.
FPR–This GCP category indicates quarry locomotor behavioral programming action. For instance, establishing the baseline through spoor platting; to include, all variable trail patterns walking, running, stopping, turning, falling, milling, hesitancies, acceleration, deceleration, etc.
Track Wall-tells direction
Cliff - occurs at the sides of the foot, indicates travel in a straight line.
Ridge - caused by pressure exerted to one side of the track, as in a turn.
Plate - high pressure against the wall definite change of direction.
Wall Explosion - sharp turn with highest degree of energy.
Cave - usually in front of track, sudden stop or jump to one side.
Track Floor–shows acceleration
Wave - small arch in the floor of the track created by the heel striking the ground, compressing soil forward, the foot rolls forward and pushes off with the toe again compressing soil to the center arch of the track. Indicates a stroll.
Double Wave - same as a disk but two arches may form. Indicates a dedicated walk. Indicates fast jog or run.
Disk - when walking the toes will tend to pile up loose soil within the front portion of the track, as the subject accelerates, the pressure transfers to the ball of the foot, which in turn transfers any loose soil farther back in the track. The farther back this disk is from the front of the track the faster the individual is accelerating. Indicates fast walk or jog.
Dish - once a toe disk passes the center of the track, it is referred to as a heel disk.
Explosion - caused by so much force that loose soil is cast out of the track, creating a huge plume. Indicates a spring or jump.
Inter-print Pitch - overall lengthwise angle of the track: Even, forward and backward pitch. Shows body posture: slumped, erect and alert, etc.
Roll - overall lateral angle of the track: no roll, right & left roll. A roll-will indicate a turn in the direction of the pitch.
Plume - dirt spread out beyond the track: in front fast gait in direction of plume, behind indicates rapid acceleration, circular pattern indicates sudden pivot.
The GCP analysis is invaluable to spoor platting. It will indicate a change of direction before it is made, show a change in acceleration and help speed up the tracking process. The only drawback is an excessive interest can slow down the tracking process.
All knowledge is in the last known track or last known spoor, when it is read correctly, the next step and meaning of the spoor-chain signature is observable and classifiable.Track slope topography illustrates the interplay between the spoor created by the foot through human locomotion and path the foot takes after it leaves the ground traveling in the air between steps. The critical points contained in the aerial travel points is the terminal point when the foot leaves the ground traveling upward to an apex and then traveling downward to an impact point where the foot again contacts the ground and accepts weight sufficient to support the rest of the body during the gait cycle.
