Sensitivity of forelimb swing phase inverse dynamics to inertial parameter errors.

The research study explores how changes in inertial parameters, specifically the mass and location of mass in limb segments, can impact the swing phase of locomotion in horses, concluding that the hoof mass is the most influential parameter in this context.

Objective of the Research

• The research aimed to investigate the sensitivity of the swing phase in quadrupedal locomotion (specifically, horse trotting) to changes in certain inertial parameters.

Methodology

• The research used sagittal plane kinematic data collected from five Dutch Warmblood horses.
• The researchers calculated swing phase forelimb net joint moments and powers at the trot using inertial parameters based on published regression equations.
• Significant peaks in the net moment and power curves were identified and measured for each forelimb joint.
• The researchers recalculated these values after modifying each of the following inertial parameters: segment mass, location of the segment centre of mass, and the mass moment of inertia.
• They then calculated the percent change in peak values per percent change in inertial parameters to pinpoint which parameters exerted the greatest influence.

Findings

• The study found that the segment mass was the most influential parameter in altering the net joint moments and powers, followed by the location of the centre of mass.
• Changes in the mass moment of inertia had a minimal impact on peak values.
• The single most influential inertial parameter was found to be the mass of the hoof segment, influencing peak changes in net joint moments and powers across all joints.

Implications

• The findings underscore the importance of accurately approximating segment masses, especially the hoof, during the swing phase of locomotion.
• They also highlight the need to account for additional masses in the model, such as shoes, which can significantly alter the locomotive dynamics.