“Muscle quality” or MQ is actually a scientific term. It means the force a muscle produces relative to its size.(1) For example, if you had two muscles that were exactly the same size, the one that produced the greater force would have the higher MQ.
How is it possible for two muscles to be the same size and yet produce different forces? Well, muscle is made up of more than just muscle fibers. Muscle has other components inside of it, including connective tissue (fibrous tissue that helps hold it together), fat, blood vessels, and fascia (tough ribbons of fibrous tissue that segment the muscle into smaller units).
A high muscle quality is like a lean piece of steak. As anyone who has ever eaten or seen a piece of steak can understand, a fatty, tough cut of steak (e.g., chuck) will have a much lower MQ than a lean, cut (e.g., filet mignon). For a given amount of muscle mass, that fatty, chuck steak will not contract nearly as effectively as the lean filet mignon.
So how is it possible for the Skulpt scanner to give you a measure of MQ when it is not measuring force or muscle size? The scanner measures the composition and structure of the muscle over a specific region. Since those two things affect how strong the muscle is, we can give you your MQ without having to do a strength measurement or taking out a tape measure!
With all this discussion about steak, you may wonder whether the MQ for a given muscle can even be changed—after all, you can’t change chuck into filet mignon or vice versa. And while you can’t turn one muscle into another, you can definitely improve a muscle’s MQ with diet and exercise. In fact, there have been scientific studies that have been proven this to be the case.(2)(3)(4)
Finally, it is worth emphasizing that strength is influenced by many factors including anatomic characteristics such as stature and limb length, proportion of Type 1 to Type 2 fibers, energy state of the muscle (i.e. fatigued or well-rested) and genetic and day-to-day variation in normal cellular function at the molecular level. All other things being equal, though, higher MQ means higher strength and better muscle definition.
 Barbat-Artigas S, Rolland Y, Zamboni M, Aubertin-Leheudre M. How to assess functional status: a new muscle quality index. J Nutr Health Aging 2012;16:67–77.
 Ivey FM, Tracy BL, Lemmer JT, NessAiver M, Metter EJ, Fozard JL, et al. Effects of Strength Training and Detraining on Muscle Quality: Age and Gender Comparisons. Journals Gerontol Ser A Biol Sci Med Sci 2000;55:B152–7.
 Brooks N. Strength training improves muscle quality and insulin sensitivity in Hispanic older adults with type 2 diabetes. Int J Med Sci 2007:19.
 Tracy BL, Ivey FM, Hurlbut D, Martel GF, Lemmer JT, Siegel EL, et al. Muscle quality. II. Effects of strength training in 65- to 75-yr-old men and women. J Appl Physiol 1999;86:195–201.