It's not always easy to track muscle development in athletes — or atrophy in aging or injured individuals. There are a variety of tools and assessments available to measure muscle strengths and weaknesses ranging from rudimentary assessments to advanced imaging analysis. As imaging analysis becomes more sophisticated, we are able to quantify and get deeper insights into muscle health than ever before. These advancements enable us to better understand the key factors in hypertrophy (growth) and atrophy (decline), and most importantly, enable athletes at every level themselves to visualize and understand their muscle health in unprecedented ways.

Below, we cover the advancement of muscle measurement capability and how we can leverage modern tools to improve athletes' development and recovery.

The Early Days: Circumference Measurement

Some of the earliest methods to measure muscle mass are still used today. One of these is the circumference measurement or girth measurement. Under this method, gains can be seen in the overall size and proportion of the athlete's limbs at a specific moment in time, but this approach fails to take into account any adipose (fat) tissue in the limb - giving the practitioner only a gross understanding of muscle changes. While being readily available and used in the field, this rudimentary visual assessment doesn't offer much guidance for future muscle growth — let alone provide any insights necessary to diagnose and treat an injury. This approach leaves the door open to further injury and opportunities to maximize performance untapped.

Challenges in Soft-Tissue Imaging

As ultrasound and computed tomography (CT) technology developed, physicians began scanning limbs to analyze muscle tissue. While these techniques provide more insights than visual assessments, they also have their limitations.

Ultrasound is widely available, affordable, and effective, with its primary benefit being the ability to produce real-time images of soft tissues. Professionals can see which muscles, tendons, and ligaments have tears or reduced fibers.

However, ultrasound has many limitations. Including:

  • It only allows for the visualization of superficial structures.
  • It is primarily 2D, with very limited 3D possibilities.
  • It is highly operator-dependent.

A muscle injury is often more complex than a simple tear and can have chain reaction effects in the muscles surrounding the injury. In many cases, a larger assessment of the muscle group or limb is needed to create a more effective treatment plan.

In addition to muscle changes, declining bone density is a critical risk factor for sports-related injuries. Computed tomography (CT) emerged as a viable alternative to ultrasound, as it was able to produce detailed images of bones and muscles. CT scans can even reveal changes in density, as well as layers of fat and fluid within muscle tissue, but gaining detailed body composition measurements from CT requires manual analysis. Moreover, CT technology also comes with a high dose of radiation.

Modern Body Composition Mapping

DEXA (dual-energy X-ray absorptiometry) then emerged as a faster way to evaluate bone density and body composition. It assesses soft tissue as well but is less able to distinguish between adipose and muscle tissue.

It is quick, convenient, and can be performed at a relatively low cost. While DEXA is sometimes used for assessing muscle changes, research demonstrates it does not reliably assess changes in muscle tissue over time.

With the launch of the first human MRI scanner, this device immediately became a game-changer as it allowed physicians to analyze both soft and hard tissue with its high resolution of muscle and body composition data, as well as the ability to evaluate the relationships among various tissue types. Applied to sports medicine, this has helped providers locate tears, assess their severity, and design more targeted treatment plans.

Unlike DEXA, the data MRIs provide can be used to reliably assess muscle changes over time, provided there is proper quantification. Yet this requires in-depth analysis that has long been limited by manual segmentation techniques. Also, standard imaging protocols typically gather data from a focal region of musculoskeletal tissue and don’t capture changes in full regions of the body - creating lost opportunities to fully understand musculoskeletal health.

From the athlete's perspective, the 2D image output makes it difficult, if not impossible, to understand how and which of their muscles are different and changing over time. Athletes who are (a) recovering from an injury or (b) seeking diagnosis for muscle dysfunction need to know which specific muscles are affected and how their volumes compare across limbs.

Fortunately for providers and patients alike, newer digital health technology has emerged to harness the full power of MRI - analyzing high-resolution scans and converting these into powerful, 3D models.

This technology uses artificial intelligence and machine learning to automate the creation of a digital muscular twin - overcoming the long-standing limitations of manual analysis and long scan times. The Springbok 3D model is so precise and detailed that it can be leveraged to run a myriad of scenarios projecting future results—e.g., a hamstring injury recovery. This allows human performance specialists to measure muscle changes over time and develop personalized post-injury treatment and injury prevention plans. Plus, the technology can be used to compare muscle volumes across different populations, so care teams can better understand how an athlete’s profile compares to their peers and identify risk factors for injury and performance.

For all of these reasons, while other imaging modalities continue to be improved upon and evolve today, MRI remains unsurpassed in analyzing soft tissue and quantifying musculoskeletal changes over time.

Conclusion: Muscle Is Complex and Requires Sophisticated Analytical Tools

Long gone are the days when providers had to rely on visual assessment or high-radiation devices to assess muscle health. The new frontier of sports tech offers precise body composition analysis that yields detailed images of the human body. We can now see the exact configuration of muscle volumes, connective tissues, and fat to best understand each athlete’s unique physiology. This is indispensable to high-performance training, quicker rehabilitation, and effective methods to reducing the risk of injury.

At Springbok, we analyze and transform MRI data into objective insights about musculoskeletal health in a faster, more precise way than is available from any other technology in the world, enabling truly personalized care at scale.

Learn more about how we're transforming precision medicine here.

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