Gym Shorts Tech Pack Guide: What to Include for Accurate Sampling and Production

A reference photo can show the general direction of a pair of gym shorts, but it cannot tell a factory everything required for accurate sampling.

It does not show the exact waistband width, inseam, pocket depth, fabric GSM, liner construction, logo position, seam type, or measurement tolerance.

That missing information is where many sampling problems begin.

A gym shorts tech pack is a production document that tells the factory exactly how the shorts should be made. It should include product sketches, measurements, fabric specifications, construction details, trims, logo information, color references, labels, packaging, and revision notes. A clear tech pack helps reduce sampling errors and gives both the buyer and factory a measurable reference for bulk production.

For brands developing custom gym shorts, running shorts, training shorts, or 2-in-1 styles, the goal of a tech pack is not to make the document look complicated.

The goal is to remove assumptions before fabric is cut.

What Is a Gym Shorts Tech Pack?

A tech pack is the technical instruction file used to communicate a product design to a manufacturer.

For gym shorts, it normally combines visual information and measurable specifications.

It may include:

• Front and back sketches
• Product measurements
• Fabric composition
• GSM or fabric reference
• Color information
• Waistband construction
• Pocket details
• Liner specifications
• Stitching requirements
• Logo artwork
• Label positions
• Packaging
• Size grading
• Revision history

During product development, we often receive buyers with a good visual concept but incomplete technical information.

For example, a buyer may send a reference image and say:

“We need this style with our logo.”

That is useful as a starting point.

But for accurate sampling, the factory still needs to know what parts should be copied, what parts should be changed, and what specifications the buyer expects.

Why Does a Tech Pack Matter for Gym Shorts?

Gym shorts can look simple from the outside but contain many construction decisions.

A single style may include:

• Elastic waistband
• Internal drawcord
• Side seam
• Side split
• Zip pocket
• Back pocket
• Mesh panel
• Compression liner
• Phone pocket
• Reflective logo
• Bonded hem

Without clear instructions, the factory has to make assumptions.

One issue we frequently encounter is that the buyer and factory interpret the same reference photo differently.

For example, the buyer may expect a 5-inch inseam, while the factory develops the sample closer to 7 inches based on the photo.

Neither side may have made a careless mistake.

The specification was simply not defined.

A tech pack turns visual expectations into measurable instructions.

What Should Be Included in a Gym Shorts Tech Pack?

A useful tech pack does not need unnecessary decoration.

It needs production information.

1. Front and Back Technical Sketches

Start with clear front and back views.

The sketches should show major features such as:

• Waistband
• Drawcord
• Pockets
• Side panels
• Side splits
• Liner
• Logo placement
• Stitch lines

If the shorts contain unusual internal construction, add inside views or detail sketches.

For custom gym and running shorts, this is especially useful for 2-in-1 styles where the outer shell and compression liner need separate instructions.

2. Measurement Specification

The size chart is one of the most important parts of the tech pack.

Common gym shorts measurements may include:

Measurement Point	Why It Matters
Waist relaxed	Controls basic waistband fit
Waist stretched	Helps evaluate waistband range
Hip	Controls overall fit
Outseam	Defines total length
Inseam	Strongly affects style and movement
Front rise	Influences fit through the front
Back rise	Affects seat comfort
Leg opening	Controls silhouette
Side split	Affects movement
Waistband height	Affects appearance and support

The factory should also know how each point is measured.

Two buyers can use the same term but measure from slightly different points.

3. Size Grading

If the sample is developed in size M, the factory still needs to know how the measurements change across S, L, XL, and other sizes.

Do not assume the factory should create grading automatically unless that has been agreed.

For established brands, the buyer's existing grading rules are usually more important than generic factory standards.

What Fabric Information Should Be Included?

“Polyester-spandex” is not enough.

A more useful fabric specification may include:

• Fiber composition
• GSM
• Woven or knit construction
• Stretch direction
• Surface
• Hand feel
• Color
• Finish
• Reference swatch

For example:

90% polyester / 10% spandex, lightweight woven, four-way stretch, matte surface, soft hand feel.

That gives the factory much more direction than simply:

Polyester stretch fabric.

During sample development, the fabric should be evaluated together with the garment construction.

A lightweight running fabric may work well for simple shorts but may not provide enough structure for large zip pockets.

Similarly, a heavier training fabric may feel too warm for a running-focused design.

How Should 2-in-1 Shorts Be Specified?

2-in-1 training shorts require more detailed tech packs because the garment effectively contains two products.

The tech pack should separate the outer shell and inner liner.

Outer Shell Information

Include:

• Fabric specification
• Length
• Side split
• Pocket construction
• Waistband
• Drawcord
• Logo

Compression Liner Information

Include:

• Fabric composition
• Stretch
• Liner inseam
• Leg opening
• Phone pocket
• Flatlock or other seam requirements
• Attachment method

For a 2-in-1 short, saying “with compression liner” is not enough.

The liner length, tightness, fabric, pocket, seam, and attachment can all change the final wearing experience.

What Pocket Details Should Be Included?

Pockets are one of the most common sources of sample revisions in gym shorts.

A tech pack should show:

• Pocket type
• Opening length
• Pocket depth
• Zip or no zip
• Zip type
• Pocket bag fabric
• Position
• Reinforcement

A phone pocket inside a compression liner needs even more precision.

If it is too small, the phone may not fit.

If it is too loose, the phone may move during training.

If the pocket sits too low, it can affect comfort.

For custom training shorts, pocket construction should therefore be treated as a functional specification rather than only a visual feature.

How Should Logo Details Be Specified?

Do not write only:

“Logo on left leg.”

A better instruction includes:

• Logo artwork
• Width and height
• Distance from seam
• Distance from hem
• Application method
• Color
• Finish

Logo techniques may include:

• Heat transfer
• Silicone
• Screen print
• Embroidery
• Reflective print

The correct method depends on the fabric, logo design, movement, wash requirements, and desired appearance.

During sample approval, logo placement should be measured rather than judged only by eye.

That makes repeat production much easier.

What Construction Details Should Buyers Define?

Construction information tells the sewing team how the garment should be assembled.

Examples include:

• Seam type
• Stitching method
• Hem construction
• Waistband attachment
• Drawcord exit
• Reinforcement
• Bartack positions
• Side split finish
• Liner attachment

You do not need to specify every technical sewing detail if you do not understand garment engineering.

But important visual or functional requirements should not be left undefined.

If necessary, the factory can recommend a construction based on the intended use.

That falls somewhere between pure OEM and ODM support.

What Labels and Packaging Should Be Included?

A tech pack should also cover the final product presentation.

This may include:

• Main brand label
• Size label
• Care label
• Hang tag
• Barcode
• Polybag
• Size sticker
• Carton mark

These details may look unrelated to garment fit, but they are part of bulk production.

One common problem is waiting until production is nearly complete before confirming packaging.

That can delay shipment.

How Should Sample Comments Be Added to the Tech Pack?

A tech pack should evolve during development.

After the first sample, create clear revision notes.

For example:

• Increase outseam by 1 cm
• Reduce leg opening by 1.5 cm
• Move logo 2 cm upward
• Increase pocket depth by 2 cm
• Change waistband drawcord to black
• Approve shell fabric
• Replace liner fabric with softer option

Avoid comments such as:

“Make it a little better.”

or:

“Pocket should feel more premium.”

These are difficult to inspect.

Good sample comments are measurable.

What Should Buyers Check During Gym Shorts Sample Approval?

Our normal sample production time is 8–10 working days once all specifications are approved, followed by approximately 5–7 days for express shipping.

When the sample arrives, buyers should check it against the tech pack.

Review:

• Fabric
• Fit
• Waist
• Length
• Leg opening
• Pocket depth
• Liner fit
• Logo position
• Stitching
• Drawcord
• Labels
• Construction

The approved sample and updated tech pack should then become the main reference for bulk production.

Our production process shows how specification confirmation, sampling, approval, and bulk production connect.

Common Gym Shorts Tech Pack Mistakes

Using Only a Reference Photo

A photo cannot define exact measurements or hidden construction.

Missing Fabric Details

Composition alone does not define hand feel, GSM, or stretch.

No Measurement Method

A number is only useful if both sides measure it the same way.

Ignoring the Liner

For 2-in-1 shorts, the liner requires its own specifications.

Unclear Pocket Dimensions

Pocket function needs measurable dimensions.

Making Bulk Changes Without Updating the Tech Pack

The latest approved version should always reflect the actual product.

Gym Shorts Tech Pack Checklist

Before sending the file to a factory, confirm that it includes:

• Front sketch
• Back sketch
• Detail drawings
• Size chart
• Measurement method
• Grading
• Fabric composition
• GSM
• Stretch requirement
• Color
• Waistband
• Drawcord
• Pockets
• Liner specifications
• Stitching
• Logo artwork
• Logo size
• Logo position
• Labels
• Packaging
• Revision number

The objective is not to create the longest document.

It is to make the product clear enough that both sides can identify whether the sample is correct.

Frequently Asked Questions

Do I need a tech pack to manufacture gym shorts?

A professional tech pack is strongly recommended for custom gym shorts, especially when the design includes custom measurements, fabric, pockets, liners, or construction. A detailed reference sample and size chart can also provide a starting point if a full tech pack is not available.

Can a factory make a tech pack from a reference photo?

A factory may help develop specifications from a reference product or concept, but a photo alone does not provide all measurements, fabric information, and internal construction details.

What is the most important part of a gym shorts tech pack?

Measurements, fabric specifications, and construction details are among the most important because they directly affect fit, performance, and repeatability.

Should a tech pack be updated after sampling?

Yes. Any approved changes should be added to the latest version so the document matches the final approved sample before bulk production begins.

Conclusion

A good gym shorts tech pack reduces assumptions between the buyer and factory.

For gym shorts, running shorts, training shorts, and especially 2-in-1 designs, the most important information includes measurements, fabric, waistband construction, pockets, liner details, logo placement, stitching, labels, and packaging.

The tech pack does not replace physical sampling.

It makes sampling more accurate and gives both sides a clearer standard for revisions, bulk production, and repeat orders.

If you already have a tech pack, reference sample, size chart, or gym shorts concept, you can contact us to send your specifications and discuss sampling or production.