Blood flow restriction training does not negatively alter the mechanical strength or histomorphology of uninjured equine superficial digital flexor tendons.
Authors: Johnson Sherry A, Sikes Katie J, Johnson James W, Van Zeeland Emily, Wist Sara, Santangelo Kelly S, King Melissa R, Frisbie David D
Journal: Equine veterinary journal
Summary
# Blood Flow Restriction Training and the Equine Superficial Digital Flexor Tendon: A Safety Profile Researchers investigating whether blood flow restriction (BFR)—a low-load exercise technique increasingly used in human rehabilitation—might safely support equine tendon healing conducted a controlled eight-week treadmill study involving eight horses, where four received pressure-specific BFR during interval walks and four received sham treatment, with untreated contralateral limbs serving as controls. Biomechanical testing revealed that BFR-exposed superficial digital flexor tendons (SDFTs) demonstrated significantly increased stiffness in both initial and final loading cycles (p=0.02 and p=0.03 respectively), though this heightened stiffness did not translate to meaningful changes in elastic modulus when adjusted for cross-sectional area, nor did histomorphological examination using standardised Bonar, Movin, and musculotendinous junction criteria reveal any degenerative alterations across treatment groups. For equine practitioners considering BFR as a rehabilitation adjunct for injured athletes, these findings suggest the technique poses no detrimental structural risk to uninjured SDFT tissue over short-term application, though the observed stiffness increase warrants further investigation to understand whether this adaptation proves beneficial or neutral during recovery protocols. Considerable uncertainty remains regarding optimal occlusion pressures and walking protocols specific to equine applications, limiting immediate clinical extrapolation; performance outcome data and longer-term follow-up remain essential before BFR can be confidently recommended alongside traditional rehabilitation strategies.
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Practical Takeaways
- •Blood flow restriction training appears safe for uninjured tendons in the short term with no detrimental histological changes, potentially offering a rehabilitation tool for equine practitioners
- •While BFR increased tendon stiffness, this did not translate to reduced mechanical strength, suggesting the change may be beneficial or neutral for controlled rehabilitation protocols
- •Optimal occlusion pressures and walking protocols for equine BFR training remain undefined and require further investigation before widespread clinical adoption
Key Findings
- •BFR-treated forelimbs showed significantly increased SDFT stiffness in both first (p=0.02) and last cycles (p=0.03) compared to contralateral untreated limbs
- •No significant differences in elastic modulus between treatment groups when normalized to cross-sectional area (p=0.5 and p=0.4)
- •No histomorphological differences were identified between BFR-treated, sham-treated, or control groups using Bonar, Movin, and musculotendinous junction evaluation criteria
- •Short-term BFR walking exercise (40 sessions over 56 days) produced no negative mechanical or structural changes to uninjured equine SDFT