# Acceleration

Definition

Acceleration at sample k is obtained by dividing the difference in Velocity, by the time difference between that sample and the previous one:

Where:

▪Ak = Acceleration at sample k,

▪Vk = Velocity at sample k.

How to specify Acceleration

1.Click the Add button next to Acceleration.

2.Complete the procedure to add the variable. See Calculate statistics: procedure.

Notes

▪If your experiment is set to Center-point, nose-point and tail-base detection, click the Body points tab and select the body points for which you want to calculate acceleration.

▪Because it is based on change in velocity, Acceleration needs three valid consecutive samples. A missing sample in your track results in missing Acceleration values in that and in the next two samples. See also the notes under Velocity.

▪Acceleration is sensitive to random changes in velocity between consecutive samples due to noise. Check the track and velocity plot to see if changes in velocity represents true acceleration. If necessary, apply Lowess smoothing to the tracks.