Developing a new adult shoe is not simply about making a sample that looks good.

A shoe can look perfect on the table, feel comfortable for the first five minutes, and still cause pressure, heel slipping, rubbing, or incorrect flexing after 30–60 minutes of walking.

This is why, during adult footwear development, we do not simply ask:

“Does the shoe fit?”

We try to answer more useful questions:

Where does it fit well? Where does it not? When does the problem appear? What is causing it? And what exactly should be changed in the next sample?

That is the difference between simply making a shoe sample and actually developing a shoe for production.

Why Adult Footwear Requires Careful Fit Testing

Adult footwear development involves more than increasing the length of an existing shoe.

An adult shoe has to accommodate body weight, walking forces, heel impact, forefoot flexing, foot movement and significant differences in individual foot shape.

Even two people who both wear EU 38 can have very different feet.

One may have a wider forefoot.

Another may have a higher instep.

Someone else may have a narrow heel but a relatively wide ball area.

For this reason, we evaluate more than shoe length.

Depending on the project, we may consider:

• Foot length
• Forefoot width
• Ball girth
• Instep girth
• Toe room
• Heel width and hold
• Arch position
• Flex point
• Overall internal volume

This becomes particularly important when developing an adult casual shoe that combines the appearance of a lifestyle shoe with some of the comfort and performance expectations of a sneaker.

Stage 1: Static Fit Testing

When a new fit sample is ready, we do not immediately ask the tester to walk for hours.

We first evaluate the shoe while standing.

The tester should ideally wear the type and thickness of socks that would normally be worn with the product.

We then check several important areas.

Toe Room

Are the toes touching the front?

Is there enough functional space for natural movement without making the shoe unnecessarily long?

Toe room should be evaluated while standing under normal body weight, not only while sitting.

Forefoot Width

The ball area is one of the most common sources of discomfort in adult footwear.

We pay particular attention to pressure around the first and fifth metatarsal areas.

A comment such as:

“The shoe feels tight.”

is not very useful for development.

A much better comment would be:

“There is noticeable pressure on the outside of my right forefoot around the fifth metatarsal.”

That gives the last maker and pattern technician something specific to investigate.

Instep Pressure

Sometimes the length and forefoot width appear correct, but the shoe still feels tight across the top of the foot.

The problem may come from:

• Instep volume
• Upper construction
• Lacing system
• Tongue construction
• Foam thickness
• Internal material thickness

Simply increasing the overall shoe size may not solve the actual problem.

Heel Fit

We also evaluate how securely the heel is held.

Does the heel feel contained?

Is the heel area too wide?

Does the collar feel secure without excessive pressure?

If the heel already feels loose while standing, heel slippage will often become more noticeable once walking begins.

Record the Left and Right Foot Separately

This is easy to overlook.

Human feet are rarely perfectly symmetrical.

One foot may be slightly longer, wider or higher in the instep than the other.

Instead of writing:

“Forefoot is tight.”

we prefer feedback such as:

Left foot: comfortable.

Right foot: slight pressure on the lateral forefoot.

This helps us determine whether we are looking at a genuine last or upper problem, or simply a natural difference between the tester’s feet.

Without this information, it is surprisingly easy to modify a last to solve an individual foot characteristic rather than a product problem.

Stage 2: Walking Test

A shoe that feels comfortable while standing may behave very differently in motion.

Once the static fit is acceptable, we move to a controlled walking test.

Depending on the product, the tester may:

• Walk normally
• Walk at a faster pace
• Go up and down stairs
• Change direction
• Stand for longer periods
• Squat
• Flex the forefoot naturally

During this stage, we pay attention to several areas.

Heel Slippage

Does the heel remain reasonably secure with each step?

If the heel repeatedly lifts, we need to understand why.

Possible causes may include overall shoe length, heel width, collar construction, topline shape or insufficient foot hold.

The correct solution is not always to make the entire shoe smaller.

Flex Point

A shoe should flex in a position that works naturally with the foot.

If the sole is too stiff or the flex point does not correspond well with the forefoot, the wearer may experience an unnatural walking motion.

It can also create:

• Unusual upper creasing
• Forefoot fatigue
• Internal foot movement
• Pressure around the ball area

This is why we observe the shoe itself as well as the wearer’s feedback.

Toe Contact During Movement

A shoe may have enough toe room while standing but still create contact during movement.

Walking quickly or going downstairs can cause the foot to move slightly forward inside the shoe.

If the toes repeatedly contact the front, we need to investigate the relationship between shoe length, heel hold and internal fit.

Heel and Collar Rubbing

Some rubbing problems do not appear immediately.

The first five minutes may feel completely normal.

After 15 minutes, the wearer notices slight friction.

After 30 minutes, the heel begins to feel uncomfortable.

This is why a five-minute fitting is rarely enough to properly evaluate a new adult shoe.

Why We Record Feedback at Different Times

One useful approach is to record fit feedback at several intervals:

0 minutes → 15 minutes → 30 minutes → 60 minutes

For example:

0 minutes:
Overall comfortable.

15 minutes:
Slight pressure developing on the outside of the right forefoot.

30 minutes:
Pressure becoming more noticeable.

60 minutes:
Clear discomfort around the fifth metatarsal area.

This tells us much more than:

“The sample is uncomfortable.”

It shows us that the problem develops under load and over time.

That information can influence whether we investigate the last, upper construction, material thickness or another component.

Stage 3: Extended Wear Testing

Once a sample performs reasonably well during the initial walking test, we can move to longer wear testing.

Depending on the shoe and development stage, the tester may wear the sample for several hours or for a significant part of a normal day.

Afterwards, we inspect both the foot and the shoe.

On the foot, we look for:

• Redness
• Pressure marks
• Heel irritation
• Toe pressure
• Localized rubbing
• Persistent discomfort

On the shoe, we look for:

• Abnormal upper creasing
• Heel deformation
• Insole movement
• Excessive material stretching
• Unusual outsole flexing
• Bonding issues
• Changes in fit as the materials settle

Some footwear problems simply cannot be discovered by walking around a sample room for five minutes.

A/B Testing: Comparing Two Sample Versions

One of the most useful techniques during repeated sample development is direct A/B comparison.

Imagine we have:

Version 7

and

Version 8

If we only give the tester Version 8 and ask:

“Does this feel better than the previous sample?”

the answer depends heavily on memory.

If the tester wore Version 7 several days or weeks earlier, remembering a small difference of only a few millimeters can be difficult.

Instead, we can compare both versions directly.

For example:

Left foot — Version 7

Right foot — Version 8

The tester walks and records the differences.

Which version has better forefoot comfort?

Which holds the heel more securely?

Which creates less instep pressure?

Which flexes more naturally?

We can then switch the shoes:

Left foot — Version 8

Right foot — Version 7

This helps reduce the influence of natural differences between the left and right feet.

For small last or upper adjustments, this type of comparison can be extremely useful.

Do Not Develop a Last Around Only One Tester

Another important principle is to avoid relying entirely on one person’s feet.

Imagine one tester has an unusually wide forefoot.

Every round, the feedback is:

“Make it wider.”

The last is adjusted.

The tester tries it again.

“Still slightly tight. Make it wider again.”

Eventually, the shoe may fit that individual perfectly.

But it could now be too wide for the majority of the intended customers.

Whenever possible, we prefer to evaluate the base size on several people with different foot characteristics.

For example:

Tester A — relatively standard foot

Tester B — slightly wider forefoot

Tester C — narrower foot or lower instep

The objective is not to create one last that fits every person perfectly.

That is unrealistic.

The objective is to determine whether the base last reasonably represents the target customer.

Use a Consistent Fit Scoring System

When several people are testing the same shoe, descriptions can become subjective.

One person’s “comfortable” may be another person’s “acceptable.”

A simple 1–5 scoring system can make feedback easier to compare.

1 — Serious problem
Significantly affects normal wear.

2 — Noticeable problem
Wearable, but revision is recommended before moving forward.

3 — Acceptable
Functional, but there is still room for improvement.

4 — Good
Comfortable with no significant fit problem.

5 — Very good
Fit and comfort meet or exceed the intended target.

We can separately score areas such as:

• Toe room
• Forefoot width
• Instep comfort
• Arch position
• Heel hold
• Collar comfort
• Walking comfort
• Flexing
• Overall fit

The number itself is not the final answer.

Its value comes from combining the score with detailed comments and the exact location of any pressure or discomfort.

Change One Variable at a Time Whenever Possible

This is one of the most important principles in footwear development.

Imagine a sample has several problems.

For the next version, we simultaneously change:

• Forefoot width
• Instep girth
• Heel width
• Upper pattern
• Foam thickness
• Insole thickness

The next sample feels better.

Great.

But now we have another problem:

Which modification actually improved the shoe?

We may not know.

Even worse, one adjustment may have solved one problem while quietly creating another.

For this reason, we try to maintain a Sample Change Log.

For example:

Version 8

Last

• Forefoot: +2 mm
• Heel area: -1 mm

Upper

• No pattern change

Insole

• Same specification

Foam

• Same thickness

Version 8 can then be compared directly with Version 7.

Now the test result becomes much more meaningful.

Local Fit Testing and Customer Testing Have Different Roles

For international footwear development, both are valuable.

Repeated local fit testing allows us to move quickly through the development process:

Fit → identify problem → modify last/upper → make another sample → test again

This can reduce unnecessary international shipping, development time and repeated sample transportation costs.

However, local testing should not completely replace customer testing.

Foot shapes, wearing habits, sock preferences, comfort expectations and target-market requirements can vary.

For this reason, we see the two stages differently:

Local Testing = Development

It helps us identify obvious problems and improve the product efficiently.

Customer Testing = Validation

It allows the brand and its target-market testers to confirm the product from their own perspective.

The two processes complement each other.

Why the First Sample Is Not the Final Shoe

This is one of the biggest misunderstandings for brands developing footwear for the first time.

It is easy to think:

“I paid for a sample, so the first sample should already be the final production-ready shoe.”

But in product development:

Development Sample ≠ Final Approved Shoe

The purpose of a development sample is to discover what still needs improvement before production.

A typical process may look something like this:

Base Last

↓

First Fit Sample

↓

Static Fit Test

↓

30–60 Minute Walking Test

↓

Problem Mapping

↓

Last / Upper Revision

↓

Second Sample

↓

A/B Comparison

↓

Extended Wear Test

↓

Customer Fit Test

↓

Further Adjustment

↓

Base Size Fit Approval

↓

Size Grading

↓

Representative Size Validation

↓

Final Confirmation Sample

↓

Pre-Production Sample

↓

Bulk Production

Not every project requires the same number of revisions.

Some products reach a good result relatively quickly.

Others require several rounds of adjustment.

The number of samples is less important than whether each sample moves the product closer to the intended result.

Approving One Base Size Does Not Approve the Entire Size Range

Suppose we finally achieve an excellent fit in EU 38.

That means:

EU 38 base fit has been approved.

It does not automatically mean every other size is correct.

The next step is grading.

Footwear grading is not simply adding the same amount of length to every size.

As the size changes, the relationship between:

length, width, girth, instep volume, heel dimensions and upper pattern

must remain appropriate.

For this reason, representative sizes should be checked after grading, particularly toward the smaller and larger ends of the range.

Some proportion or fit problems only become visible once we move away from the base size.

When Should You Commit to Expensive Outsole Tooling?

This is especially important when a project requires a completely custom outsole.

A last can usually still be adjusted during development.

An upper pattern can be revised.

But once production outsole tooling has been completed, major changes become significantly more expensive and difficult.

Whenever the construction allows it, we prefer to resolve the major questions around:

Fit → Last → Upper → Proportion → Last/Outsole Relationship

before committing to final production tooling.

Moving faster is not always the same as saving money.

Spending additional time on fit development can be far less expensive than discovering a fundamental problem after production tooling—or thousands of pairs—has already been completed.

What Do We Actually Approve in the Final Sample?

Final approval is about much more than comfort.

Before production, the final product may need approval across several areas.

Fit

Does the shoe achieve the intended fit and comfort?

Appearance

Are the overall proportions and shape correct?

Materials

Are the upper, lining, foam, insole and other materials final?

Color

Do the production colors match the approved standard?

Logo

Are the logo size, position, orientation and application correct?

Construction

Does the final construction match the approved specification?

Workmanship

Are stitching, bonding, edge finishing and overall assembly acceptable?

Outsole

Are material, hardness, tread, flexing and appearance correct?

Sizing

Have the base size and representative graded sizes been validated?

Once these elements are approved, the project can move toward a:

Final Confirmation Sample / Golden Sample

This sample becomes an important reference for production and quality control.

Depending on the project, a Pre-Production Sample (PPS) may then be produced using the final production materials, tooling and manufacturing specifications before bulk production begins.

Making a Sample vs. Developing a Product

There is a significant difference between the two.

Making a sample

means producing one pair of shoes.

Developing a product

means understanding:

Why does it fit?

Why does it not fit?

Where exactly is the problem?

Should we modify the last, upper or internal materials?

Did the modification actually improve the next version?

Does the base size still work after grading?

Can the approved result be reproduced consistently across hundreds or thousands of pairs?

That is product development.

When a customer receives the first sample and provides detailed fit feedback, we do not automatically see that as a failed sample.

In many cases:

That feedback is one of the most valuable parts of the development process.

A Better Way to Think About Footwear Testing

The entire process can be summarized quite simply:

Sample

↓

Wear

↓

Observe

↓

Record

↓

Modify

↓

Compare

↓

Test Again

↓

Validate

↓

Approve

This may look slower than making one sample and immediately approving it.

But what we are really trying to reduce is risk.

Because once bulk production begins, a fit problem is no longer a one-pair problem.

It can become a:

1,000-pair problem.

Or even a:

5,000-pair problem.

Final Thoughts

A good adult shoe is rarely created by guessing every dimension correctly on the first attempt.

It is usually developed through a repeated process of:

Testing → observing → analyzing → modifying → testing again.

The most important question is not:

“How many samples did we make?”

The better question is:

“What did we learn from each sample, and did each version move us closer to the right product?”

Development may require more time at the beginning.

But identifying problems with the last, fit, upper construction, materials or grading before production can prevent much larger costs later—including rework, returns, customer complaints and damage to a new brand’s reputation.

Making one pair of shoes is not the hardest part.

The real challenge is developing a shoe that can be reproduced consistently, across multiple sizes and production quantities, while still delivering the fit and experience the brand intended.

That is why we believe good footwear development should never be based on guesswork.

It should be based on testing, recording, improving and validating.

— Linsaifu Footwear