Inertial sensors reliable, accurate in horse gait analysis, review finds

Inertial sensor technologies can monitor and quantify horse locomotion with high accuracy and precision, the authors of a just-published review have concluded.

The technology, which employs inertial measurement units (IMUs), has proven to be reliable for the evaluation of horse–rider interactions, Cristian Mihăiță Crecan and Cosmin Petru Peștean reported in the journal Sensors.

The pair, with the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, in Romania, conducted a narrative review to explore the performance, efficacy, and applicability of IMU-based sensor systems in equine gait analysis.

IMUs are wearable sensors that measure acceleration forces and angular velocities, providing the possibility of a non-invasive and continuous monitoring of horse gait during walk, trot, or canter during field conditions.

They noted that, in equine science, objective gait analysis methods have been frequently used to assess movement asymmetry and locomotion characteristics of horses, especially as part of lameness evaluations.

“Lameness has a high prevalence in horses and can have serious consequences for animals, owners, and veterinarians, including removal from athletic activity, reduced performances, and financial loss.” Lameness may also affect spinal biomechanics, they said.

“Due to their high accuracy and sensitivity, IMUs have gained popularity over objective measurement techniques such as force plates and optical motion capture systems.”

Relevant scientific publications for inclusion in the review were identified by performing a non-systematic literature search in the PubMed database using keywords.

The authors said they found many examples in the literature that support the versatility and usefulness of IMUs for the evaluation of equine gait asymmetries indicative of lameness.

“Most studies evaluated and compared several IMU methods based on accelerometer and gyrometer data and compared their findings with reference data obtained with well-established objective kinetic and kinematic methods.

“The collected evidence indicated that IMU-based sensor systems can monitor and quantify horse locomotion with high accuracy and precision, having comparable or superior performance to objective measurement techniques such as force plates and optical motion capture systems.

“Based on the published data reviewed here, we can conclude that IMUs can play an important role in equine medicine and research.”

The pair said the technology’s accuracy and precision, as well as its good performance, has been demonstrated both in field and in laboratory conditions.

“As their sensitivity is superior to that of the human eye, IMUs can represent a valuable tool, especially for junior veterinarians faced with the challenge of diagnosing mild lameness.

“Their advantages also include the possibility of gathering objective movement data in field conditions, where the use of well-established methods like force plates and optical motion capture would be impractical or cumbersome.”

However, IMUs also have several disadvantages, they said, one of which is their cost.

To obtain reliable and reproducible data, they said care must be taken in placing the sensors in the right position.

“We strongly advise veterinarians who are considering introducing IMUs in their clinical practice to strictly adhere to the sensor placement recommended by the manufacturer of each system.

“An additional limitation is represented by the fact that a stable internet connection is needed to avoid errors in data.”

They noted that, in human studies, novel IMU-based methodologies and procedures are continuously emerging to assess movement analysis and biomechanical properties of the foot.

In human musculoskeletal research, a combination of IMUs, optical motion capture, machine learning gait prediction, and finite element analysis has been used for injury monitoring, treatment, and rehabilitation.

“These techniques can also be extrapolated to animal studies, with research in this direction having recently been conducted.”

Data collected by IMU systems are valuable for the evaluation of horse–rider interactions during dressage riding, the training of horses, or coaching.

The authors acknowledged limitations in their review. “The present study is a narrative review without a pre-specified search and selection methodology (as opposed to systematic reviews); hence, the conclusions drawn could be biased and could not be applicable in a more general context.”

They said that IMU systems in equine gait analysis warrant further research. They urged a special focus on the potential implementation of novel techniques described and validated in humans.

Crecan, C.M.; Peștean, C.P. Inertial Sensor Technologies—Their Role in Equine Gait Analysis, a Review. Sensors 2023, 23, 6301. https://doi.org/10.3390/s23146301

The review, published under a Creative Commons License, can be read here.