Modern Fit: How Did Footwear Get Here? Origins of the Fit Crisis

Explore the intricate world of footwear fit, from the uniqueness of human feet to the limitations of traditional sizing systems, and discover how IAMBIC is revolutionizing the industry with precision-fit solutions.

By Maeve Wang & Frank Mojica


Twenty billion pairs of shoes are sold around the world every year. From athletic to formal to workwear, we have endless options for styles. But what about options for fit? The industry’s sizing system focuses on two dimensions: length and width. This two-dimensional mass-standardization overlooks the true extent to which each of our feet differ, leaving 63–72% of people wearing shoes that don’t properly fit.1 Beyond comfort, poorly fitting footwear detrimentally impacts our health and quality of life — and a deficit in understanding this impact persists. To tackle the footwear industry’s fit crisis, we must begin with untangling its origins: why is poor fit so prevalent and how did we get here?

Behold the human foot

Shoes wrap one of the most overlooked, but complex parts of the human body. Each foot is unique, consisting of 26 bones, 33 joints, and over 100 muscles, tendons, and ligaments, all accompanied by a multiplex network of nerves, blood vessels, skin, and tissue.2 These intricate, load-bearing structures absorb up to three times our body weight with every step, balancing our bodies so we can stand upright, leap, and run.3 Feet provide balance and agility, tell us where we stand in the environment, and protect our other muscles and joints by dissipating shock.4 5 Simply put — feet are essential for active participation in daily life. Hylton Menz, Ph.D., professor at La Trobe University in Melbourne, Australia, and the world’s top-ranked expert on foot research, explains:

Finding the perfect fit can be complex, as it is influenced not only by foot shape, but also by biomechanical factors such as the way the foot joints move when walking, and the mechanical behaviour of the wide range of materials that are used in shoe manufacture. The perfect fitting shoe is therefore the shoe that incorporates an individual’s unique structure, function and preferences, and enables them to optimally perform daily tasks in a safe and comfortable manner. 6

To add complexity, contrary to conventional wisdom, feet don’t stop growing in adulthood. Our feet are so dynamic that they change at every stage of our lives. As fat pads on the bottom of each foot wear thin with age, shock absorption diminishes and calluses and corns settle in.7 Feet expand from pregnancy, weight gain, genetics, and deformities from wearing poor-fitting footwear.8 And over time, ligaments and tendons grow lax, allowing feet to spread ever longer and wider.9

Further complicating fit is the fact that our feet are expanding collectively as a species. Since the 1970s, average shoe sizes in the U.S. have grown by almost one full inch across the board.10 For women, the average size rose from 6.5 to between 8.5 and 9 — for men, from 8.5 to 10.5.11 12 Experts attribute this growth to processed foods, healthcare access, and the rise of obesity, where this final factor has also been correlated with lower medial longitudinal arches, which in turn lengthens feet. 13 14Taken together, variations from individuality and the oppressive march of age and time influence the unique experiences we each have wearing shoes every day. But have shoes kept pace with our evolving personal and collective needs?

Starting with the last

Shoemaking is an elaborate craft, but one that’s been simplified to a point that makes fit elusive. The process starts with the creation of a “last” — a three-dimensional mold that shoes are built on. Over this last, an “upper” — the top part of a shoe covering the foot — is cut, stretched, and stitched with delicate precision. Once components such as the heel, sole, and tongue are added with careful detail, the last is removed and the completed shoe remains intact.15 Since the last provides both the mold and support to assemble every component of a shoe, it is arguably the most crucial step in the process. Lastmaking is a craft so nuanced that it can take anywhere from 4 to 20 years to fully master.

A root cause of our fit crisis today rests in how lasts have been simplified and standardized to enable fast — and mass — production.16 In the mid-20th century, the industry offered more options, especially in width. Over time, brands cut back on wide and narrow options and settled on one standard width for each length.

“As mass production grew with offshoring production in the 1970s, most brands reduced these offerings even further to one standard size in each size range,” Natacha Alpert, founder of MIRAS3D, former head of Nike’s Digital Product Creation, and an industry thought leader with over 20 years of experience in 3D scanning, design, and manufacturing innovations, says. “This is a big obstacle today with consumers in that most brands cannot accommodate the varied specialized narrow and wide widths needed.”17

Today, 99% of shoes sold in the U.S. are imported from China, Vietnam, Indonesia, and other regions, and the suppliers for shoe materials have also moved abroad.18 Domestically, production costs are higher than other regions, making low-price, high-volume manufacturing in the U.S. a challenge.19 While offshore, mass manufacturing has made shoes cheaper and more abundant, it has sacrificed size range and variety, leaving fit out of reach for two out of every three people.

Furthermore, offshore manufacturing is a system that’s slow to respond to collective change, even to a phenomenon like the rise in average sizing that has unfolded for half a century. This has rendered size ranges obsolete across the industry, with manufacturers producing limited selections of larger sizes and retailers hesitant to stock them.20 Accommodating for these trends would further complicate the already expensive, complex process of shoemaking, as Alpert explains:

Manufacturing complicates responding to these issues because as consumers aren’t able to buy the correct shoe sizes, it’s difficult to get accurate forecasting on their purchases and exact fit needs if size standards within a brand aren’t actually catering to the exact sizes and widths needed by their customers.21

A Catch-22 scenario has emerged. Limited sizing options yield limited opportunities for acquiring the necessary data on people’s fit requirements. As a result, it’s grown increasingly challenging for shoemakers to understand their customers — let alone their own products.

How fit is framed

On top of the complexity of people’s footwear needs and a lumbering supply chain, the basic framework of measuring fit is faulty. Even if shoemakers had all the high-resolution data on people’s feet and gait, applying this data to their shoe sizing and designs would be a challenge. As it stands, sizing is approached from the perspective that emphasizes the size of the shoe, instead of the foot that’s meant to fit inside the shoe. This creates issues because shoes are designed with “toe allowance” — the empty space between the tip of the toes and the front of the shoe — which impacts size and fit. Toe allowance has two functions: physical allowance — wiggle room for toes — and fashion allowance — the aesthetic shape of the toe box. With toe allowance, part of the shoe goes unused, leaving the portion that’s meant to be filled by the foot as the shoe’s “effective length.” But both toe allowance and effective length vary based on the shoe type, silhouette design, material, and other factors, meaning that shoes of various lengths can fit a given foot.

Image by Tanya DeSelm, IAMBIC INC. All rights reserved.

In the 1970s, SATRA — a UK-based footwear testing and research center — proposed Mondopoint, a radically different system for sizing. Mondopoint contrasts with all other sizing systems in that it’s the only one based on foot dimensions rather than last dimensions.22 However, since Mondopoint is based on foot dimensions, conversion to this system requires lastmakers, shoemakers, retailers, and customers to be aligned on the exact measurements of feet intended to fit shoes made from any specific last. Historically, this has been a tall order, because participants across an industry’s entire supply chain would need to opt into an entirely new system and establish tight controls on product design, manufacturing, and marketing. Yet, such an overhaul in how footwear is delivered would generate data on not only people’s fit needs, but also on the design intent of each shoe — allowing people to more easily find the shoes that would best fit them.


Ultimately, footwear fit is a complex and important issue. Although human feet are powerful, dynamic, and crucial organs, more work must be done to serve their health and safety. But solutions are on the way. “We are in a new era where fit, customization and comfort are increasingly valued as priorities for form and design in footwear,” Alpert said. “Designs and trends will be influenced by 3D scanning for fit technologies and generative design tools as we gather data and make more consumer focused decisions in the footwear industry.”23 These solutions will involve both scientific and technical innovations that merge our evolving understanding of the relationship between footwear and the human body. The next installments of Modern Fit will explore the damaging, often permanent, health consequences of poor footwear fit and the future of the industry.


IAMBIC is a next generation shoe brand delivering precision-fit shoes at scale through merging AI, virtual scanning, and streamlined manufacturing — making footwear finally inclusive. IAMBIC’s patent-pending, National Science Foundation-backed technological innovations are developed with the world’s top foot and footwear researchers, industrial designers, and passionate creatives. Learn more at


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