Comparison of kinematic symmetry index calculations and the effects of straight and circular trotting.

The research investigates the comparison of three different methods of kinematic symmetry index calculation in horses while they are trotting. These methods are evaluated through straight and circular trotting simulations, determining their effectiveness in assessing movement symmetry.

Objective and Methods

The main aim of the study was to compare three different methods of symmetry calculations, specifically focusing on:

• The motion of tuber coxae versus sacrum
• The effects of circular trotting
• The impact of using entire trialing sessions instead of distinct stride calculations

To conduct the research, the team used inertial sensors which were attached to the sacrum and both the left and right tuber coxae (LTC and RTC) in 21 non-lame horses. The symmetric indices were calculated based on vertical movements for every stride, utilizing three methods that had previously been published.

Results Interpretation

The analysis of the results showed that the Fourier analysis (Method 2) had considerably higher ratio values compared to the other two methods:

• Displacement amplitude ratio (Method 1) assessing the tuber coxae
• Displacement amplitude ratio (Method 1) assessing the sacrum
• Difference between the displacement of the LTC and RTC (Method 3)

The study also considered the effects of circular trotting within these methods, which varied significantly but did not display any significant difference among the methods.

The researchers also discovered that there were no notable differences between whole trial calculations and individual stride calculations.

However, when comparing Method 2 and Method 1, the former tended to underestimate asymmetry, due to the use of squared amplitudes. Furthermore, Methods 2 and 3 were less accurate during circular trotting because of changes in the amplitude timing.

Conclusion

The study concluded that notable differences exist in symmetry indices when applying varied methods and locations on the same dataset. Also, there are discrepancies in terms of accuracy when applied to circular data. As such, the study advises taking caution when interpreting and directly comparing different symmetry indices.