Exercise does not affect stiffness and mineralisation of third metacarpal condylar subarticular calcified tissues in 2 year old thoroughbred racehorses.

The researchers investigated if exercise affects the stiffness and mineralization of certain bony areas in two-year-old racehorses, finding no noticeable effect despite the increased load these areas carry during physical activity.

Background of the Study

• The study investigated whether exercise affects the stiffness and mineralization of certain bony structures in young racehorses. Specifically, the areas looked at were subarticular calcified tissues located just below the articular cartilage in the horses’ third metacarpal bone (Mc3), which are involved in load transmission during exercise.
• The researchers built on the knowledge that high-impact exercise significantly improves the density of a horse’s epiphyseal bone (the end part of a long bone).

Methodology

• This investigation studied eight 2-year-old Thoroughbred racehorses. Half of these horses were trained, while the other half were untrained.
• The researchers used nanoindentation to measure the elastic modulus of the minerals found in these horses’ bones. This basically measures the stiffness of these tissues on a nanometric scale.
• They also used quantitative backscattered electron imaging to determine the concentration of minerals in the studied tissue, specifically in the palmar medial and lateral condyles (parts of the bone surface) of the Mc3.

Findings

• There was no difference noted between the trained and untrained horses when it came to mean stiffness or mineral content in the subchondral bone (the layer of bone just underneath the cartilage) or in calcified cartilage.
• Despite these parts of the bone transmitting increased load during exercise, the structure of these tissues remained the same whether the horses were exercised or not.
• This led the researchers to conclude that, in the specific regions studied, the tissues appeared optimised for function, and their structural attributes were not altered by the increased loads associated with exercise.

Implications of the Study

• The results of this study might suggest that the stiffness and mineralization of certain areas of a horse’s bone are optimized for functionality and not significantly affected by exercise, even when this increases the load on these areas.
• This could have implications for understanding horse physiology, athletic training, or potentially clinical applications related to bone health and load transmission.