How does exercise intensity and type affect equine distal tarsal subchondral bone thickness?

Area of Science:

• Equine biomechanics
• Veterinary orthopedics
• Sports science

Background:

• Osteochondral tissue adaptation is strain-dependent, influenced by exercise.
• Exercise intensity and type may cause site-specific strains, affecting adaptation and injury risk.
• Understanding subchondral bone (SCB) thickness patterns is crucial for equine joint health.

Purpose of the Study:

• To investigate the relationship between exercise type/intensity and equine distal tarsal SCB thickness patterns.
• To determine if high-intensity exercise induces site-specific increases in SCB thickness.
• To compare SCB thickness across different anatomical locations and exercise groups.

Main Methods:

• Magnetic resonance imaging (MRI) of equine cadaver distal tarsi.
• Measurement of SCB thickness at defined dorsal and plantar locations.
• Comparison of SCB thickness between low-intensity (general purpose, horse walker) and high-intensity (elite competition, race training, treadmill training) exercise groups.

Main Results:

• Elite competition and race training showed increased SCB thickness compared to low-intensity exercise.
• General purpose horses exhibited greater lateral SCB thickness than medial.
• Horse walker exercise resulted in thicker lateral and medial SCB compared to the midline.
• Elite competition linked to increased medial SCB in proximal small tarsal bones and lateral SCB in distal bones.
• Race training and treadmill training showed minimal site differences, with a general trend of lateral > medial SCB.

Conclusions:

• Exercise intensity and type differentially affect SCB thickness patterns in equine distal tarsal joints.
• Specific high-intensity exercise regimens are associated with distinct medial-lateral and proximal-distal SCB thickness variations.
• Findings highlight the site-specific nature of SCB adaptation to exercise in horses.