A critical appraisal of javelin high speed cinematography results using a computer flight simulation program

Abstract

Errors in javelin release parameters obtained from high-speed film analysis of real throws have been quantified in order to assess the accuracy of studies that assume a rigid body javelin model when measuring human performance characteristics. Human digitizing errors and the inadequate rigid body javelin model represent increments of up to 6 m in range as predicted by a computer flight simulation program. These errors result from difficulties in digitizing blurred javelin coordinates caused by large release speeds and javelin flutter. Errors in release-pitch rate are as high as 27·0%. Digital filtering methods tend to underestimate transiational and angular speeds such that errors in previous literature represent simulated range increments of up to 29 m. This is owing to the filtering methods interpreting high frequency flutter as noise. It is concluded that present methods in javelin film analysis are inadequate for measuring absolute values of release parameters and need to be revised. Accurate quantification is essential before simulation programs can be used in a human performance perspective.

Keywords:

• Javelin
• Film analysis
• Errors
• Performance modelling