Balancing training load, rest and musculoskeletal injury risk: a mathematical modelling study in Thoroughbred racehorses

TL;DR

This study uses a mathematical model to analyze how different training regimens affect bone injury risk in racehorses, highlighting the importance of rest and training volume for injury prevention.

Contribution

It extends an existing bone adaptation model to evaluate various training strategies, providing insights into optimizing training for injury risk reduction in racehorses.

Findings

Lower training volume with high-speed work reduces bone damage.

Frequent and longer rest periods decrease injury risk.

Mathematical model guides training program design for horse welfare.

Abstract

Musculoskeletal injuries (MSI) in Thoroughbred racehorses are a leading cause of death and premature retirement in racehorses and are heavily influenced by training practices. Greater distances of high-speed galloping accumulated during racing campaigns are associated with MSI. Bone injury is the most common MSI, and understanding how training practices influence bone damage accumulation is critical for improving both horse welfare and racing outcomes. This study builds on an existing mathematical model of bone adaptation and damage to investigate the impact of different training programs on bone injury risk. Several training programs (three progressive, four race-fit, six rest programs and two with rest replaced by low-intensity training) were constructed to reflect representative practices undertaken by professional trainers in Victoria, Australia. Training programs varied in training volume, rest frequency and program duration. Lower volume training programs that included high-speed training, achieved sufficient bone adaptation with less accumulation of bone damage, and subsequently lower risk of bone failure. In addition, incorporating more frequent rests (at least 2 per year) and/or longer rest periods (at least 6 weeks) reduced bone damage due to the extended opportunity to remove and repair bone damage. These results provide an in-silico mathematical model of the bone response to training, demonstrating the effects of training programs on bone adaptation, damage formation and repair. The findings can guide the design of training programs that balance both bone adaptation and bone health throughout horses racing career.