The Protraction and Retraction Angles of Horse Limbs: An Estimation during Trotting Using Inertial Sensors

Abstract

The protraction and retraction angles of horse limbs are important in the analysis of horse locomotion. This study explored two methods from an IMU positioned on the canon bone of eight horses to estimate these angles. Each method was based on a hypothesis in order to define the moment corresponding with the verticality of the canon bone: (i) the canon bone is in a vertical position at 50% of the stance phase or (ii) the verticality of the canon bone corresponds with the moment when the horse’s withers reach their lowest point. The measurements were carried out on a treadmill at a trot and compared with a standard gold method based on motion capture. For the measurement of the maximum protraction and retraction angles, method (i) had average biases (0.7° and 1.7°) less than method (ii) (−1.3° and 3.7°). For the measurement of the protraction and retraction angles during the stance phase, method (i) had average biases (4.1° and −3.3°) higher to method (ii) (2.1° and −1.3°). This study investigated the pros and cons of a generic method (i) vs. a specific method (ii) to determine the protraction and retraction angles of horse limbs by a single IMU.

Detection of Horse Locomotion Modifications Due to Training with Inertial Measurement Units: A Proof-of-Concept

“…IMUs have been used effectively in the field to characterize anomalies in horse locomotion since they offer a non-invasive wearable measurement of locomotor indicators. These sensors have been proposed as an aid for lameness detection [15][16][17], for gait classification [18], for horse speed estimation [19], for evaluation of the effect of shoes on break over [20], or for the evaluation of different rehabilitation methods [20]. They also offer an alternative to traditional systems such as optoelectronic systems to identify the phases of locomotion [21][22][23][24][25] or estimate the horse's protraction and retraction angles [16].…”

Inertial Sensor Technologies—Their Role in Equine Gait Analysis, a Review

“…In addition, stance and stride duration measurements had a higher precision [ 56 ]. As opposed to OMC, these angular velocity methods were also able to accurately estimate protraction and retraction angles of horse limbs [ 57 ].…”

A Method for Quantifying Back Flexion/Extension from Three Inertial Measurement Units Mounted on a Horse’s Withers, Thoracolumbar Region, and Pelvis

“…Many studies have demonstrated that inertial measurement units (IMUs) are a real alternative to motion capture systems [ 17 ]. The use of IMUs allows the recording of the horse’s locomotion with onboard technologies and in field conditions [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Stance-phase detection methods from IMUs mounted on canon bones [ 18 , 21 , 22 ], pasterns [ 22 ], and hooves [ 22 , 23 , 24 ] have been recently developed.…”

“…Stance-phase detection methods from IMUs mounted on canon bones [ 18 , 21 , 22 ], pasterns [ 22 ], and hooves [ 22 , 23 , 24 ] have been recently developed. IMUs also allow the measuring of protraction and retraction angles [ 19 ]. Some studies also developed asymmetry quantification methods to assist with veterinarian examinations [ 20 , 25 , 26 ].…”