Royal Society open science2026; 13(10); 260818; doi: 10.1098/rsos.260818

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

Anwar, MN
·
Pan, M
·
Morrice-West, AV
·
Malekipour, F
·
Pivonka, P
·
Flegg, JA
·
Whitton, RC
·
Hitchens, PL

Abstract: Musculoskeletal injuries (MSI) in Thoroughbred racehorses are a leading cause of death and premature retirement, 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 programmes on bone injury risk. Several training programmes (three progressive, four race-fit, six rest programmes and two with rest replaced by low-intensity training) were constructed to reflect representative practices undertaken by professional trainers in Victoria, Australia. Training programmes varied in training volume, rest frequency and programme duration. Lower-volume training programmes 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 (minimum of two per year) and/or longer rest periods (minimum of six weeks) reduced bone damage owing to the extended opportunity to remove and repair bone damage. These results provide an mathematical model of the bone's response to training, demonstrating the effects of training programmes on bone adaptation, damage formation and repair. The findings can guide the design of training programmes that balance both bone adaptation and bone health throughout a horse's racing career.

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Publication Date: 2026-10-07 PubMed ID: 42840916PubMed Central: PMC13641913DOI: 10.1098/rsos.260818Google Scholar: Lookup

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Overview

This study uses a mathematical model to understand how different training programs affect the risk of bone injuries in Thoroughbred racehorses.
It aims to optimize training load and rest to improve horse welfare and racing performance by reducing musculoskeletal injuries.

Background and Importance

Musculoskeletal injuries, particularly bone injuries, are the main reasons Thoroughbred racehorses retire early or die.
Training practices, especially the amount of high-speed galloping, influence the accumulation of bone damage that can lead to injuries.
Improving the understanding of how training affects bone health is crucial for both horse welfare and competitive success in racing.

Objective of the Study

To use an existing mathematical model of bone adaptation and damage accumulation to analyze how different training and rest schedules impact the risk of bone injuries in racehorses.
To simulate representative training routines used by professional trainers and predict the balance between beneficial bone strengthening and harmful bone damage.

Methodology

Development and use of a mathematical model that captures:
- Bone adaptation in response to mechanical load (training).
- Damage accumulation resulting from repeated loading.
- Bone repair processes during rest periods.
Simulation of several training programs structured as follows:
- Three progressive programs that gradually increase training intensity and volume.
- Four race-fit programs designed to mimic intensities during active competition phases.
- Six rest programs with different frequencies and durations of rest incorporated.
- Two programs where rest was replaced by low-intensity training instead.
Training variables included:
- Training volume (amount and intensity of workload).
- Frequency of rest periods.
- Duration of rest periods.

Key Findings

Lower-volume training with high-speed components:
- Achieved sufficient bone adaptation, meaning bones got stronger.
- Resulted in less bone damage accumulation compared to high training volumes.
- Led to a lower overall risk of bone failure or injury.
Incorporating rest periods had significant benefits for bone health:
- A minimum of two rest periods per year helped reduce bone damage levels.
- Longer rest durations (at least six weeks) allowed adequate repair of bone damage.
- Rest gave the bone time to recover, preventing excessive damage build-up.
Replacing rest with low-intensity training was less effective at allowing bone repair, potentially leading to higher injury risk.

Practical Implications

The study provides a quantitative framework to design training schedules that maximize bone strength while minimizing injury risk.
Professional trainers can use these insights to:
- Employ lower volumes of carefully structured high-speed training.
- Schedule appropriately timed and sufficiently long rest periods.
- Avoid continuous high training loads without adequate recovery, which could lead to bone damage accumulation.
This balanced approach could improve the longevity and performance of racehorses and reduce the incidence of career-ending injuries.

Summary

This research advances understanding of musculoskeletal injury risk by modeling how different combinations of training load and rest affect bone adaptation and damage.
It highlights the importance of rest for bone repair and suggests that optimal training involves managing intensity and rest frequency to safeguard horse health.
The findings are directly relevant to the Thoroughbred racing industry, offering evidence-based guidance for training program design.

Cite This Article

APA

Anwar MN, Pan M, Morrice-West AV, Malekipour F, Pivonka P, Flegg JA, Whitton RC, Hitchens PL. (2026). Balancing training load, rest and musculoskeletal injury risk: a mathematical modelling study in Thoroughbred racehorses. R Soc Open Sci, 13(10), 260818. https://doi.org/10.1098/rsos.260818

Publication

Royal Society open science

ISSN: 2054-5703

NlmUniqueID: 101647528

Country: England

Language: English

Volume: 13

Issue: 10

Pages: 260818

PII: 260818

Researcher Affiliations

Anwar, Md Nurul

Equine Centre, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Werribee, Victoria, Australia.
School of Mathematics and Statistics, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia.

Pan, Michael

Equine Centre, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Werribee, Victoria, Australia.
School of Mathematics and Statistics, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia.

Morrice-West, Ashleigh V