Like variables, the parameter functions are split into function groups.

### Time

Functions in this group all return a time, either in seconds or normalized to percent if you specify the **Time Normalize Between** events.

**Event A.**The time of A.**Event A to Event B.**The duration from A to B.**Variable A max value [Event A, Event B].**The time when variable A attains its maximum value between two events of type A and B.**Variable A min value [Event A, Event B].**As above, but for the minimum value.**Variable A crossing Value going up [Event A, Event B].**The time of variable A crossing a Threshold value on the way up, between two events of type A and B.**Variable A crossing Value going down [Event A, Event B].**As above, but crossing the threshold going down.

### Total time

These functions calculate the total time a variable fulfils a certain condition.

**Above Value [Event A, Event B].**The total time a variable is above a certain threshold value, in seconds, between events A and B.**Below Value [Event A, Event B].**As above, but the time the variable is below the threshold value.

### Frequency

This group contains only one function.

**[Event A, Event B]**, this calculates how often the event pair A and B occurs. This could, for example, be used to calculate cadence, which is the step frequency, by specifying event A as**foot strike**and B as**foot off**. Although the standard unit for frequency is Hz, you can also choose units such as steps/min.

### Value

These functions calculate the value of a variable, or the value of a combination of variables, at specific points in time.

**Variable A [Event A].**Simply the value of the variable at the time specified by the event.**Variable A [Event A] + Variable B [Event B].**The two variable values added together, the values taken at the points in time specified by events A and B, respectively.**Variable A [Event A] –****Variable B [Event B].**Variable B subtracted from A.**Variable A range [Event A, Event B].**Variable A’s range (that is, its minimum value subtracted from its maximum value) for the time span defined by events A and B.**Variable A max [Event A, Event B].**Variable A’s maximum value for the time span defined by events A and B.**Variable A min [Event A, Event B].**As above, except for Variable A’s minimum value.

### Integrated

This group contains only one function.

**Variable A [Event A, Event B],**calculates the integral over the time span defined by events A and B.

### RMS

This stands for “root mean square”, which adds up the square of all sample points and finally returns the square root of the sum.

**Variable A [Event A, Event B].**Calculates the RMS of variable A between the events A and B.**Variable A –****Variable B [Event A, Event B].**Calculates the RMS of the difference between variables A and B over the time span defined by events A and B.

### Average

These functions calculate the average value of a variable, or a combination of variables.

**Variable A [Event A, Event B].**The average of each sample point over the time span defined by events A and B.**Variable A’s local coordinates in Variable B [Event A, Event B].**Variable A can be either a point or a segment, whereas variable B has to be a segment. The function calculates the average position (and, if a segment, orientation) of A in B’s reference frame. The main use of this function is to store an anatomical point or segment in a technical segment’s reference system based on a static trial, which can be used later in a dynamic trial.

### Stdev

Equivalent to the average function above, except that it calculates the standard deviation.

- Only
**Variable A [Event A, Event B]**is available.

### 3D

Functions in this group calculate parameters based on 3D variables.

**Distance Variable A [Event A] to Variable B [Event B].**Calculates the straight-line distance from the 3D variable A to the 3D variable B.**Speed Variable A [Event A, Event B].**Calculates the speed of 3D variable A between event A and event B. This corresponds to the distance covered divided by the time between the two events.**Distance Travelled Variable A [Event A, Event B].**Calculates the 3D distance traveled by variable A between events A and B. This is calculated by adding each line segment traveled for each frame between the two events.

### Temporal

These are special functions for calculating typical temporal parameters.

**Single Support [Event A, Event B] – [Event C, Event D].**Calculates the time between events A and B, but then subtracts the time*outside*the span defined by event C to event D, should either of these lie inside the A to B span. When A = ipsilateral foot contact, B = ipsilateral foot off, C = contralateral foot off and D = contralateral foot contact, single support is calculated as the total stance time (A to B) minus the time of double support (A to C and D to B). However, should C and D lie outside the span A to B (for example when a running motion is analyzed), nothing is subtracted since there is no double support.**Double Support [Event A, Event B] – [Event C, Event D].**Calculates the time from event A to event B minus the time*inside*the span defined by event C to event D.

### Parameter

These functions enable you to combine other parameters.

**Parameter A + Parameter B.**Adds two parameters.**Parameter A –****Parameter B.**Subtracts parameter B from parameter A.**Parameter A * Parameter B.**Multiplies the two parameters.**Parameter A / Parameter B.**Divides parameter A with B.**(Parameter A + Parameter B) / 2.**Takes the average of two parameters.