Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on Fitness & Recovery. Browse all Fitness & Recovery education

If you have ever wondered why some athletes seem injury-prone while others bounce back from heavy training, part of the answer lives in your connective tissue — and one of the most studied genes behind it is COL5A1. This gene shapes the collagen that gives tendons and ligaments their strength and elasticity, and its variants have been linked to both injury susceptibility and, intriguingly, endurance performance.

What COL5A1 does

COL5A1 provides instructions for making part of type V collagen, a protein that regulates how collagen fibrils assemble in skin, tendons, ligaments, and other tissues. Type V collagen acts like a template: it controls the diameter and organization of the larger collagen fibers that give connective tissue its tensile strength. When that regulation shifts, the mechanical properties of tendons and ligaments shift with it — affecting how they handle load, stretch, and repeated strain.

The rs12722 variant and injury susceptibility

The most researched COL5A1 variant is rs12722, in a region of the gene that influences how the collagen message is regulated. The T allele has been associated in multiple studies with a higher risk of soft-tissue injuries, including Achilles tendon problems and anterior cruciate ligament (ACL) injuries. The proposed mechanism is that certain variants alter collagen fibril properties, changing tendon and ligament stiffness in ways that affect injury tolerance. Evidence varies across populations, so this is a contributing factor, not a single cause.

COL5A1 and endurance performance — the flip side

The same gene has a more surprising association. Some COL5A1 variants linked to stiffer connective tissue have also been connected to better running economy and endurance performance. Stiffer tendons can store and return elastic energy more efficiently, which may benefit repetitive endurance movement even as it changes injury risk. It is a reminder that a variant is rarely simply "good" or "bad" — the same biology can be an asset in one context and a liability in another.

Related connective-tissue genes: TNC, GDF5, and MMP3

COL5A1 works within a network. TNC (tenascin-C) contributes to tendon structure and has been studied alongside COL5A1 in Achilles injury research. GDF5 influences ligament, tendon, and joint development and is associated with osteoarthritis and connective-tissue traits. MMP3 encodes an enzyme that remodels the collagen matrix. Variants across this network combine to shape your overall connective-tissue resilience, which is why single-gene thinking rarely tells the whole story.

What your results reveal

Genetic insight into connective tissue is context, not a scoreboard. The PlexusDx Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights, including markers in the fitness and recovery category, so you can understand your baseline injury and recovery tendencies. It does not diagnose an injury or predict a specific outcome — it gives you information to train smarter and to discuss with a coach or provider.

Training and recovery informed by genetics

Whatever your COL5A1 profile, the fundamentals protect connective tissue: progress training load gradually, warm up thoroughly, build tendon capacity with consistent loading, prioritize recovery and sleep, and address niggles before they become injuries. Someone with an injury-associated variant is not destined to get hurt — but that knowledge can be a good reason to be especially disciplined about warm-ups, progression, and rest.

Frequently Asked Questions About COL5A1 and Injury Risk

What does the COL5A1 gene do?

COL5A1 provides instructions for part of type V collagen, which regulates how collagen fibrils assemble in tendons, ligaments, and skin. It effectively sets the template for connective-tissue strength and elasticity, so its variants influence how your tendons and ligaments handle load, stretch, and repeated strain.

Does the COL5A1 rs12722 variant mean I will get injured?

No. The rs12722 T allele has been associated with higher risk of Achilles and ACL injuries, but it is one contributing factor among many. Training load, technique, warm-up, and recovery matter enormously. A variant signals a tendency worth managing, not an injury that is guaranteed to happen.

Can COL5A1 variants help athletic performance?

Some can. Certain COL5A1 variants linked to stiffer connective tissue have also been associated with better running economy and endurance performance, because stiffer tendons return elastic energy efficiently. The same biology that changes injury risk can benefit endurance, which is why context matters when interpreting results.

How can I use genetic information about injury risk?

Use it to train smarter, not to worry. Knowing you carry an injury-associated variant is a reason to be disciplined about gradual load progression, warm-ups, tendon conditioning, and recovery. Genetic insight informs your approach; a coach or qualified healthcare provider helps you apply it to your specific goals.

Want to understand your connective-tissue and recovery pathways? Take the Precision Peptide Genetic Test to see the pathway-level insights behind your biology.

This article is part of the PlexusDx Education Hub. Browse all Fitness & Recovery education

Disclaimer: The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use, and it does not diagnose, treat, cure, or prevent any disease. Genetics is a guide, not a guarantee. Consult a qualified healthcare provider before beginning any peptide protocol or making changes to your care.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.