Exercise-induced tendon hypertrophy: cross-sectional area changes during growth are influenced by exercise

Area of Science:

• Equine sports medicine
• Tendon biomechanics
• Developmental orthopedics

Background:

• Skeletal tissues adapt to mechanical loads, but mature equine superficial digital flexor tendons (SDFT) show limited adaptation.
• The SDFT is prone to injury in athletic horses, highlighting the need to understand its developmental plasticity.

Purpose of the Study:

• To investigate if imposed exercise during growth influences SDFT cross-sectional area (CSA) in Thoroughbred foals.
• To test the hypothesis that exercise promotes SDFT development and potentially increases its capacity to withstand athletic demands.

Main Methods:

• Fourteen Thoroughbred foals were divided into control (pasture exercise) and exercise (pasture + daily treadmill) groups from 2 to 15 months of age.
• Pasture activity was objectively monitored; SDFT CSA was measured at various time points.
• Statistical analysis compared CSA and its rate of increase between groups.

Main Results:

• The exercise group exhibited a significantly greater rate of increase in SDFT CSA over time compared to the control group.
• While some timepoints showed larger CSA in the exercise group, variance influenced significance.
• No significant difference in pasture activity was observed between groups, though males were more active.

Conclusions:

• Exercise during growth can modulate equine SDFT development, leading to increased CSA.
• This developmental plasticity suggests exercise may enhance tendon strength and injury resistance in athletic horses.
• Early exercise interventions could be crucial for optimizing tendon health for future performance.