As thoughts turn towards the 2026 World Cup in North America, global focus will fall on elite performance, speed and precision. Beneath that spectacle lies a quieter variable: the interaction between foot, boot and surface. 

Football boots are marketed around power, control and speed. Yet their design influences traction, load distribution and injury risk in ways that are not always visible. For podiatrists working across sport, MSK and rehabilitation settings, footwear design is not a peripheral issue – it sits at the intersection of performance and pathology. 

We revisit our conversation with Dr Katrine Okholm Kryger, one of the world’s leading football boot researchers, to explore what boot design reveals about biomechanics, stress fractures, “invisible” injuries and why women’s football footwear still lags behind the men’s game. 

Designing for performance and safety 

A football boot must balance three competing demands: performance, safety and comfort. 

“It’s a holistic process,” says Dr Katrine Okholm Kryger, senior lecturer in sports rehabilitation at St Mary’s University. “You want the player to perform optimally, but you don’t want them to get injured. And it has to feel right on the foot.” 

Boot design is shaped by multiple interactions – between boot and player, boot and surface, boot and ball, and even boot and other players. Stud configuration influences traction, the upper affects ball control and fit determines how forces are transmitted through the foot. 

At times, design trends have created unintended risks. Long bladed studs, popular in the early 2000s, were associated with laceration injuries when contact occurred at speed. Design choices do not operate in isolation. 

Traction, load and acute injury 

Traction is widely considered a key factor in many acute football injuries.  

“If studs get stuck in the ground, you can see ankle sprains or ACL injuries,” Kryger explains. “If traction is too low, players may slide and overstretch.” 

Stopping forces are absorbed somewhere. The more abruptly a boot grips the surface, the more load passes through the ankle, knee and hip. Stud design and surface interaction therefore have biomechanical consequences that extend beyond grip alone. 

Repetition, bending points and stress fractures 

Injury is not always sudden. Repetitive load can be equally problematic. 

Overuse injuries arise when tissues are repeatedly stressed without sufficient adaptation. In football boots, the location of studs influences where the boot bends. Unlike a running shoe, which flexes along more natural anatomical lines, a football boot bends between studs. 

“If the studs aren’t positioned where the foot is meant to bend, it bends over bone,” says Kryger. “And that’s not very nice.” 

High pressure beneath the first and fifth metatarsals has been associated with stress fractures in some players. Poor overall fit can also contribute to plantar fascia irritation, Achilles discomfort and heel instability. 

The invisible injuries: comfort and performance 

Not all performance-limiting injuries are dramatic. 

Blisters and friction burns rarely appear in epidemiological data because they do not necessarily prevent play. But discomfort influences fatigue, movement patterns and decision-making. 

“The only study where I found a measurable performance difference was around comfort,” Kryger says. “Players wore very lightweight ‘speed’ boots for 90 minutes. In the final 20 or 30 minutes they were actually slower because the boots were less comfortable.” 

Comfort, often overshadowed by marketing claims, remains one of the most consistent performance factors. 

Fit, anatomy and the problem of width 

Fit remains one of the most complex challenges in football footwear. 

During her doctoral research, Kryger encountered an England international of West African descent who had been playing in boots four sizes too large to accommodate width. The solution had not been anatomical – it had been compensatory. 

Traditional boot shapes are often based on narrow anatomical assumptions. For players with wider feet, sizing up may feel like the only option, even if it compromises control and stability. 

Custom-made boots exist but remain limited to a small number of elite players. For most, fit remains constrained by mass production. 

Women’s football: a developing evidence base 

Recognition of anatomical and movement differences in women’s football has grown significantly in recent years, but the evidence base is still progressing. 

Women’s feet often demonstrate differences in arch height, heel shape and proportional toe length, alongside variations in movement patterns, muscle mass and power output. These factors can influence how boots interact with the playing surface, particularly in relation to traction and bending mechanics. 

“We strongly question whether a men’s soft ground boot is optimal for women,” Kryger says. 

In response, manufacturers have begun developing models designed specifically for the women’s game, and recent collaborative research involving Women’s Super League teams and Leah Williamson has started to identify key performance and injury-related questions. 

For now, clinical considerations centre on helping players achieve an optimal fit and selecting an appropriate outsole for the surface and conditions they face.  

Clinical takeaways for podiatrists 

Football boots are marketed around speed, control and power. Performance claims often focus on marginal gains – lighter materials, sharper traction, more aggressive stud configurations. Yet Kryger’s research suggests that many of these features make little measurable difference to performance. 

“The only study where I found a difference was around comfort,” she explains. “We took very lightweight boots and had players run for 90 minutes. In the final 20 to 30 minutes, they were actually slower because the boots were less comfortable.” 

Comfort, she argues, remains the most reliable performance factor. Poor fit and discomfort may not prevent participation, but they can influence load tolerance and fatigue. 

Stud configuration and traction also warrant careful consideration, particularly in players returning from injury. High-traction soft ground boots may increase stopping forces, placing greater load through the ankle and knee. For athletes in later-stage rehabilitation, a slightly lower-traction outsole may provide a more graduated return to full match demands. 

“It’s about being cautious,” she says. “Soft ground boots will stop you faster, but your body then has to cope with that load. If there is a little more give, it allows time to adapt.” 

For podiatrists working with footballers at any level, understanding the interaction between fit, bending mechanics and traction may be as important as the marketing narrative surrounding performance. 

About the interviewee 

Dr Katrine Okholm Kryger is a medical specialist at UEFA. She is also a visiting professor in women’s football at Manchester Metropolitan University. She was formally an associate professor in sports rehabilitation at St Mary’s University.  

Dr Kryger is one of the leading researchers examining football boot design and lower limb biomechanics. Her work explores how traction, fit and bending mechanics influence injury risk and performance in elite football. She has collaborated with professional teams and footwear manufacturers and has been a driving force in the women’s football boot field to address longstanding gaps in sports footwear design. 

Disclaimer 

Dr Katrine Okholm Kryger is a medical specialist at UEFA. The views expressed here are her own and a summary of an interview given in 2022.