A fitness apparel product video has to answer what a buyer cannot test through a screen: is it see-through when I squat, does it stay up when I run, how does it stretch, and how will it look on a body like mine. Those answers have to come from real footage of the real garment, because an AI model will happily render leggings that stay opaque in any pose, which is a claim your fabric may not keep. Where AI earns its place is everything around the garment: the gym or trail, the hard light, the movement in a brand clip, the 9:16 cut for Reels. On 8frame, use the clip maker's Fitness preset with photos of the real pieces in the Outfit slot, keep every fabric claim on screen as text you can back up, and film the proof shots on a phone.
TL;DR
- Proof is real, mood is generated. Squat tests, stretch tests, waistband tests and fit on different bodies come from your own footage. Generated clips carry the brand: place, light, motion.
- On 8frame: the Fitness preset ("Movement, hard light, cuts on the beat") opens at 4 scenes, 15 seconds, 9:16. Slots: Person (3 photos recommended), Gym (1), Outfit (1), Gear (1, optional), Style (1).
- Claims need evidence. The FTC says advertisers need "a reasonable basis" for claims before an ad runs. "Squat-proof", "sweat-wicking" and "compression" in a caption are claims.
- Fixed prices on the board: Kling v3 Standard 86 credits for 5 s with sound, Kling 2.6 Pro 95 (47 silent), Veo 3.1 Fast 168 for 8 s with sound, Nano Banana 2 at 11 per image.
- Movement must be plausible. Models get exercise mechanics subtly wrong. Keep generated movement simple and leave technique to real coaches on real video.
What an activewear buyer is really checking
Fashion video sells a look. Activewear video sells a look and a function, and the function is what drives returns. Before you plan any clip, list the questions your reviews and returns already tell you buyers ask. For most activewear they are:
- Opacity. Is it see-through in a deep squat or a forward fold?
- Hold. Does the waistband roll or slip during running and jumping?
- Stretch and recovery. How far does the fabric stretch, and does it bag at the knees?
- Fit across bodies. How does the same size look on different heights and builds?
- Colour. Is the colour on screen the colour that arrives, under gym light and daylight?
Every one of those is a physical property of your fabric. A video model does not know your fabric's properties; it draws a plausible garment. It will not show the sheerness of a lightweight legging under a ring light, and it will not show a waistband rolling down. That is why a generated clip can only carry the mood, and the proof has to be filmed.
The two halves of a product video
The real half. A phone on a tripod, a plain wall, daylight or your studio light. Film one squat from behind and the side, one stretch test with hands on the fabric, one jump or sprint start, and the same piece on two or three people of different builds who agreed to appear. These shots are short and they do not need to be beautiful; they need to be honest. Keep them ungraded so the colour is true.
The generated half. The brand frame around the proof: a hard-lit gym at 6 a.m., a trail at sunrise, a slow-motion stride, a close shot of fabric moving. This is where the Fitness preset does its work.
Cut the two together in the Video Editor: open on a generated brand shot, put the real proof in the middle, end on the product name, price and size range as text.
Making the generated half on 8frame
1. Fill the Fitness preset slots
Open the Fitness preset in the clip maker. Its question is "What are we training today?".
- Person (three recommended). Photos of the athlete or model who will wear the pieces, with their permission. Face, full body and a side view.
- Gym (one). Your gym, a studio, a track, a trail, whatever place your brand lives in.
- Outfit (one). A clean photo of the real piece or set, front on, on a plain background. If the set has a print or a logo, make sure it is sharp in this photo.
- Gear (optional). A kettlebell, a mat, a skipping rope: only if it belongs in the story.
- Style (one). A frame from a campaign whose hard light and grade you want.
2. Write the idea, then fix the script
Describe one training moment in a sentence: "the athlete sprints out of the blocks on an empty track at dawn, hard side light, fabric tight on the stride". The clip maker drafts a script by scene. Edit any line that makes a claim about the garment ("sweat-proof", "zero transparency", "compression that boosts performance") unless you can prove it, and any line that describes an exercise you would not coach.
3. Render, then check the garment and the movement
The render button shows its credit price before you press it. The clip maker renders all scenes as one video. Check each scene against your Outfit photo (colour, seams, logo, length) and watch the movement: a knee caving in, a rounded back under a bar or an impossible landing reads as fine to most viewers and as wrong to anyone who trains. Our fitness video guide explains why form is a hard line. Re-shoot any scene that drifts; a failed scene can be retried without touching the rest, and failed generations are refunded automatically.
4. Assemble and add the facts
In the Video Editor, cut your real proof clips between the generated ones. Add captions from a pasted script (there is no transcription), and put the fabric composition and size range on screen as text. Keep filter presets off the proof clips so the colour stays true. For music, ElevenLabs Music on the board is 81 credits per started minute; if you join clips that carry sound, do it on the Video Editor timeline, because the Montage node (10 credits) joins the picture only and its file has no audio track.
Prompts for the brand shots
Prompt:
The athlete from the reference photos sprints out of a crouch on an empty running track at dawn wearing the set from the outfit photo, low camera at hip height, hard side light, slow motion on the first two strides, the set keeps its exact colour, seams and logo position
Prompt:
Close shot of the leggings from the outfit photo as the athlete from the reference photos steps up onto a wooden box in a concrete gym, hard overhead light, fabric moving with the knee, then a slow tilt up to the waistband, colour unchanged
Prompt:
A quiet studio at sunrise, the person from the reference photos rolls out a mat and stands still in the set from the outfit photo, window light across the floor, slow push in, calm breathing, no exercise performed
Prompt:
Rain on a city running path at night, the athlete from the reference photos runs past the camera wearing the jacket from the outfit photo, street lights reflecting in the wet fabric, camera pans to follow, the jacket's colour and logo as in the photo
The third prompt deliberately avoids an exercise. For yoga, mobility or lifting brands, a still or slow moment is safer than a generated movement that a coach would correct.
Which model for which shot
Fixed prices per clip, in credits, for single shots on the board:
| Model on the board | Credits | Good for | The catch |
|---|---|---|---|
| Kling v3 Standard | 86 for 5 s with sound, 57 silent | Animating a photo of the athlete in the real set | Needs a start image; 720p |
| Kling 2.6 Pro | 95 for 5 s with sound, 47 silent | A 1080p brand shot, including from text alone | Sound is a toggle |
| Veo 3.1 Fast | 168 for 8 s with sound | A run or gym scene with ambient sound | 16:9 or 9:16 only; from an image it is locked to 8 s |
| Seedance 2.5 | 157 for 5 s at 720p | An extra scene on the model family the clip maker calls | Tops out at 720p |
| Nano Banana 2 (image) | 11 per image at 1K | A still of the set in your gym for a thumbnail or a first frame | A still; check colour and seams before animating it |
No video model on 8frame outputs 4K and there is no video upscaler. For product page uploads, Shopify accepts product videos up to 10 minutes and 1 GB as MP4, MOV or WebM.
Fabric and performance claims
This is general information, not legal advice.
- Evidence first. The FTC's small-business advertising guide says advertisers "must have evidence to back up their claims" and that before an ad runs a company needs a "reasonable basis" for its claims, meaning "objective evidence that supports the claim." Opacity, moisture-wicking, compression level and UV protection are objective claims.
- Pictures are claims. The same guide says the FTC looks at the ad in context, "words, phrases, and pictures". A generated clip that shows a legging staying opaque in a deep squat is a picture making the opacity claim, whether or not the caption says it.
- Fibre names. Where an ad states fibre content, the FTC's textile rules (16 CFR 303.42) ask that fibres making up 5 percent or more of the fibre weight be named by generic name in descending order of weight, and that extra statements about fibre content not mislead. "Recycled" or "merino" on screen should match the label.
- Before and after. TikTok's ads policy bans "product effect comparisons, such as before-and-after results" that may give a false or distorted impression. A shaping garment shown on and off with a generated body change is the case to avoid.
- AI labels. TikTok also asks for its AIGC label or your own clear disclaimer on significantly AI-edited content. See do you have to disclose AI-generated ads.
Rather have the clips made for you?
If you run an activewear brand and want the brand clips without learning a new tool, the 8frame team can make them for you: 10 clips in 5 business days for $490, with one round of changes, made in the same Fitness preset this guide uses. Send photos of the pieces and a short brief on the done-for-you fitness clips page. To make them yourself instead, open the Fitness preset in the clip maker and follow the steps above.
FAQ
Can AI show how my leggings fit?
It can show a plausible fit, not your fit. A model draws a garment that looks right on the body in the reference photos; it does not know your fabric's stretch, weight or opacity. Film fit and squat tests on real people, and use AI for the brand shots around them.
Fashion or Fitness preset for activewear?
The Fitness preset, if the clip is about movement: it has Person, Gym, Outfit and optional Gear slots and opens with hard light and cuts on the beat. The Fashion preset suits a styled look in an editorial setting. Pick one per clip; both let you change scenes, length and aspect ratio.
Can I say "squat-proof" in my video?
Only if you have objective evidence for it, such as your own documented tests. The FTC requires a reasonable basis for objective claims before an ad runs, and a generated clip showing the fabric opaque in a squat is a claim too.
How long should an activewear product video be?
For Reels and TikTok, 10 to 20 seconds is enough for a brand shot, two proof shots and an end card. The Fitness preset opens at 15 seconds with 4 scenes; set 10 or 20 if you need to.
What does a product video cost on 8frame?
The clip maker shows the price of each render on its button before you press it. Single shots have fixed prices, such as Kling v3 Standard at 86 credits for 5 seconds with sound and Veo 3.1 Fast at 168 for 8 seconds with sound. Plans start at $19 a month for 1,000 credits; Creator is $49 for 3,000.
Sources
- FTC, Advertising FAQ's: A Guide for Small Business (evidence and "reasonable basis"; "words, phrases, and pictures"), checked 2026-11-04
- FTC textile rules, 16 CFR 303.42 (fibre content in advertising: generic names in order of predominance by weight, 5 percent threshold, extra statements must not mislead), checked 2026-11-04
- TikTok ads policy, misleading and false content (before-and-after comparisons; AIGC label or own disclaimer): ads.tiktok.com, checked 2026-11-04
- Shopify Help Center, product media types (videos up to 10 minutes and 1 GB; MP4, MOV, WebM), checked 2026-11-04
- 8frame prices, presets, defaults and limits: the 8frame app, checked 2026-11-04
Try it without signing up: the 8frame canvas opens on a real board. The canvas is free and unlimited; generation is paid from $19/month.