Crossover Step Screen

Flag foot placements narrower than a caller-supplied step-width limit.

Description

Crossover-step screening compares signed mediolateral placement with a minimum step width.

Crossover-step screening compares signed mediolateral placement with a minimum step width. Negative placement remains meaningful under the caller’s coordinate convention.^[1]

Flag foot placements narrower than a caller-supplied step-width limit.

When to use Crossover Step Screen

Use this tool to flag foot placements narrower than a caller-supplied step-width limit.

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

How to use Crossover Step Screen 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 mediolateralFootPlacementCm, minimumStepWidthCm using the field table and calculation rules, then run the tool.
Read stepWidthMarginCm, crossoverFlag. 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
mediolateralFootPlacementCm	Mediolateral foot placement cm	number	Required
minimumStepWidthCm	Minimum step width cm	number	Required

Enter finite signed placement and nonnegative minimum cm. Return signed margin and strict flag.

margin=placement−minimum; flag=margin<0

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

Output field	Meaning	Value type
stepWidthMarginCm	Step width margin cm	number
crossoverFlag	Crossover flag	boolean

json

{
  "input": {
    "mediolateralFootPlacementCm": -2,
    "minimumStepWidthCm": 0
  },
  "output": {
    "stepWidthMarginCm": -2,
    "crossoverFlag": true
  }
}

Limitations and assumptions

No video tracking or automatic crossing identification is performed.

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. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Step Width Screen: Compare step width with caller-provided base-of-support limits. For a complementary task, use Foot Strike Contact Classifier: Classify first-contact location on a normalized heel=0 to toe=1 axis using caller-defined regions.

References

Crossover Step Screen — tool.io

Similar or alternative tools

Step Width Screen
Compare step width with caller-provided base-of-support limits.
Foot Strike Contact Classifier
Classify first-contact location on a normalized heel=0 to toe=1 axis using caller-defined regions.