This is some text inside of a div block.

Muscle Asymmetry: The Implications for Health, Longevity and Performance

To better understand and evaluate an individual’s specific muscular composition, including muscle volume, symmetry/asymmetry, 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 analysis, as well as fat infiltration, scar tissue and edema measurements within each individual muscle.

Springbok's innovation unlocks more comprehensive and objective evaluation of muscle health, informing training and precision health interventions across performance, life sciences, as well as general health and longevity. Our technology makes it possible for clinicians, researchers, performance coaches and the general population to understand complex MSK data and help to drive better preventive care measures, athlete development and rehabilitation protocols, and research and clinical decisions.

Understanding Muscle Asymmetry

Variations in muscle symmetry between left and right are more common in elite athletes due to sport-specific training, heavy usage, and skill development. However, muscle asymmetry can be a warning sign that precedes debilitating (and oftentimes chronic) overuse injuries among all people, not just athletes. 

Understanding muscle asymmetry is crucial for contextualizing performance adaptations, understanding compensation during recovery, and developing predictive indices for injury in sport and among the general population. It is also important to understand normative ranges of asymmetry among athletes and people in general, as some level of asymmetry is likely to be present, and in some cases, necessary.

We are transforming how muscle is understood and analyzed, and with that comes the work to create the necessary resources, frameworks and context for effective, personalized evaluations to inform the decisions to lead to better health outcomes, whether that is in sport, recovery or general day-to-day life.

For example: when comparing our male and female normative databases, the mean percentage of asymmetry was higher in females for twenty-seven of the thirty-eight muscles. This difference in average asymmetry levels across biologic sexes suggests that the implementation of sex-specific normative databases will provide more representative comparisons that better reflect what is expected for a particular subject.

What does the science say?

The related literature highlights the importance of muscle symmetry across a wide variety of populations. Muscle asymmetry can indicate compensation following injury recovery [Silder et al. (2008), Skeletal Radiol 37], and a muscle asymmetry threshold of 15% or higher has shown to be linked with increased injury [Knapik et al. (1991), AM J Sports Med 19; [2] Croisier et al. (2008), AM J Sports Med].  While these thresholds help create basic guidelines to help predict injury and understand possible performance adaptations, it fails to individualize expected asymmetry by muscle function, performance, and related to sex. 

There are several more studies similar to the above that show the importance of muscle symmetry and how it relates to general health, athletic performance and longevity. We want to offer a quick disclaimer related to athletes, though. In many sports and types of physical movement, some level of asymmetry is both inevitable and important. Previous research has demonstrated interlimb asymmetries are common in soccer players (an example of an asymmetrically demanding sport), while low interlimb asymmetries are found in symmetrically demanding sports, such as track athletes. 

Asymmetries from the Springbok scan were consistent with a tennis player's loading and impact patterns. This athlete was referred for a scan after injuring their calf, and the scan revealed significant imbalances (the gastrocnemius medial head was 9.7% larger on the left side).

Overhead athletes, such as tennis and volleyball players, will have different muscle imbalances compared to a runner or cyclist that will help them perform their sport at the best. What is important is for athletes to be baseline measured against themselves and relevant databases, whether it is other athletes in the same sport or athletes at the same position within team sports. At Springbok, we are eager to learn more about the unique adaptations amongst participants in each sport we work with, as it will further our understanding of the optimal training, recovery and rehabilitation protocols. This is why we are so focused on building proper normative and sport-specific databases.

The importance of baseline measurements against oneself also apply to those interested in understanding muscle asymmetry as it relates to disease, longevity and overall health.

Enter personalized muscle analysis technology

A Springbok scan gives detail to even the smallest of muscles, providing a degree of granularity when visualizing muscle variations side-by-side. Understanding if the small stabilizer muscles are imbalanced can impact how a person’s larger muscles function, and ultimately how well they are performing in their sport or activity of choice.

The implications of muscle imbalances can be far-reaching for all people, from professional athletes to the military, seniors and the general population. It is important to provide context to asymmetry data gleaned from a Springbok scan, and like most things related to the human body, there is nuance and interconnectedness with muscle asymmetries that warrant further analysis.

Using our control database, we have been able evaluate normal levels of asymmetry between the left and right muscles. For some people, asymmetry may be desirable, such as on a dominant kicking leg for certain types of athletes. In other people, and particularly the general population, asymmetry may be detrimental, or indicate injury potential. With a Springbok scan, muscle asymmetries can be analyzed at an individual muscle level, or by functional group, creating a more  complete picture of an individual's musculature that can be used for training, rehabilitation, injury assessment, and as a predictive function.

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.