Foot Strike Contact Classifier

Classify first-contact location on a normalized heel=0 to toe=1 axis using caller-defined regions.

Description

Contact-location classification partitions a heel-to-toe axis using supplied boundaries.

Contact-location classification partitions a heel-to-toe axis using supplied boundaries. It labels location rather than impact mechanics.^[1]

Classify first-contact location on a normalized heel=0 to toe=1 axis using caller-defined regions.

When to use Foot Strike Contact Classifier

Use this tool to classify first-contact location on a normalized heel=0 to toe=1 axis using caller-defined regions.

Prepare the measured movement, timing, load or preassigned score requested. Keep protocols, units, paired measurements and caller-selected thresholds consistent.

How to use Foot Strike Contact Classifier and understand its results

Prepare the measured movement, timing, load or preassigned score requested. Keep protocols, units, paired measurements and caller-selected thresholds consistent.
Enter contactPositionFraction, rearfootUpper, midfootUpper using the field table and calculation rules, then run the tool.
Read contactClass, marginAboveRearfoot. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
contactPositionFraction	Contact position fraction	number	Required
rearfootUpper	Rearfoot upper	number	Required
midfootUpper	Midfoot upper	number	Required

Enter position 0–1 and boundaries with 0≤rearUpper<midUpper≤1. Return class and signed position-minus-rear-boundary margin.

rearfoot if position≤rearUpper; midfoot if position≤midUpper; otherwise forefoot

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
contactClass	Contact class	string
marginAboveRearfoot	Margin above rearfoot	number

json

{
  "input": {
    "contactPositionFraction": 0.8,
    "rearfootUpper": 0.3,
    "midfootUpper": 0.7
  },
  "output": {
    "contactClass": "forefoot",
    "marginAboveRearfoot": 0.5
  }
}

Limitations and assumptions

No actual contact detection, shoe effect or injury interpretation is supplied.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Shoe Heel Drop: Compute heel-to-forefoot shoe drop and screen a supplied zero-drop tolerance. For a complementary task, use Vertical Loading Rate: Calculate vertical loading rate from the supplied measurements.

References

Foot Strike Contact Classifier — tool.io

Similar or alternative tools

Shoe Heel Drop
Compute heel-to-forefoot shoe drop and screen a supplied zero-drop tolerance.
Vertical Loading Rate
Calculate vertical loading rate from the supplied measurements.