Fat Infiltration: What Role Does it Play with Muscle Function and Performance?

To better understand and evaluate an individual’s specific muscular composition, including muscle volume, symmetry, and fat infiltration, Springbok’s AI technology produces a 3D digital twin of the musculoskeletal (MSK) system. We are unlocking a new way to view and understand muscle, providing muscle volume metrics through a personalized Springbok Score, which compares an individual’s muscle volume against a normative database, left-right asymmetry measurements, as well as fat infiltration, scar tissue and edema within muscles.

Springbok delivers a more comprehensive and objective evaluation of muscle health, informing training and precision health interventions. Its technology makes it possible for clinicians, researchers, performance coaches and the general population to understand complex MSK data and inform better preventive care measures, athlete development and rehabilitation protocols, and research and clinical decisions.

Understanding fat infiltration

Intramuscular fat infiltration, also known as intramuscular adipose tissue, refers to the distribution and composition of fat within the skeletal muscles of an individual. It represents the extent to which fat is accumulated within the muscle fibers, contributing to the overall muscular composition. While a certain amount of intramuscular fat is normal and functional, an excessive or imbalanced composition of intramuscular fat can have implications for both muscle performance and metabolic health in humans.

Common causes of fat infiltration found in research studies include age, physical inactivity, and disuse due to injury. As we age, research shows that we can lose between 1 to 5 percent of muscle mass and strength each year after the age of 30. This age-related muscle loss, known as sarcopenia, is often coupled with fat infiltration if muscle mass isn’t actively maintained through lifestyle and exercise. All else equal, the more an individual moves, the more muscle is maintained, which can translate to less fat infiltration. 

Temporary muscle loss following an injury or surgery can be high as 30 percent in the affected area. This can include fat infiltration in specific muscles around the injured area, evident in the rotator cuff, lower back pain, disc herniation, and ACL. Even if the muscle returns to normal size after rehabilitation, there can be a reduction in muscular composition, which would include an increase in fat infiltration.

Not all adipose (or fat) tissue is equal. Where a person’s body stores fat, rather than total body adiposity, may be more important in understanding the risk to overall health. While the link between visceral fat and risk of cardiovascular and metabolic conditions is well-established,  intermuscular fat is also linked to poor health outcomes, as well as decreased strength and performance potential in athletes.

Research shows that fat stored within the muscle is associated with chronic inflammation, impaired glucose tolerance, increased total cholesterol, and decreased strength. In a study conducted with over 1,000 participants, greater muscular fat infiltration was associated with higher all-cause mortality and cardiovascular mortality. 

Older adults are particularly susceptible to the effects of fat infiltration. Weak or underdeveloped musculature can contribute to incidents of falls and when coupled with osteoporosis, can affect quality of life and longevity. And athletes who have higher levels of fat infiltration in their muscles may experience weaker muscle strength and reduced mobility, which can negatively impact sports performance. 

Enter personalized muscle analysis technology

It is easier than ever before to get a sound estimate of body fat percentage with scales and handheld devices, but measuring muscle quality for insights into fat infiltration has long been relegated to clinicians, and not accessible for most people, even those who stand to benefit the most (especially those suffering from muscular disease, including FSHD).

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Springbok's technology leverages AI and the accuracy of magnetic resonance imaging (MRI) to transform static 2D imagery into precise 3D muscle assessments. A Springbok scan takes less than 15 minutes and unlocks a new way to view and quantify muscular composition, including volume, asymmetries, fat infiltration and atrophy, as well as soft tissue injuries and scar tissue. 

To learn more or request a demo, please visit here.

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