Pretrained computer vision classifier

Identify arm vs leg muscle with one API call.

A pretrained arm vs leg muscle classifier that sorts an image into one of 2 categories. Use the arm vs leg muscle API immediately, no training required, then adapt it to your own data when you need more.

Pretrained · Nyckel-trained 2 labels out of the box Image input

Try the arm vs leg muscle classifier

Drop in a photo and get the prediction back. No signup, no setup.

What this arm vs leg muscle classifier recognizes

A sample of the 2 labels this pretrained classifier chooses between.

Arm Muscle
Leg Muscle

Need a label that isn't here? Clone the classifier into your Nyckel console and edit the label set to fit your data.

Call the arm vs leg muscle API

Once you've added this classifier to your console, you get your own copy of it behind your own endpoint. Invoke it with any HTTP client:

curl

curl -X POST "https://www.nyckel.com/v1/functions/YOUR_FUNCTION_ID/invoke" \
  -H "Authorization: Bearer $NYCKEL_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"data": "https://example.com/photo.jpg"}'

Python

import requests

# Get an access token: https://www.nyckel.com/docs/api/overview/authentication/
token = "YOUR_ACCESS_TOKEN"

response = requests.post(
    "https://www.nyckel.com/v1/functions/YOUR_FUNCTION_ID/invoke",
    headers={"Authorization": "Bearer " + token},
    json={"data": "https://example.com/photo.jpg"},
)
print(response.json())

Example response

{
  "labelName": "Arm Muscle",
  "labelId": "label_...",
  "confidence": 0.92
}

Under the hood

Model type
Nyckel-trained

Trained on a Nyckel-curated dataset covering 2 arm vs leg muscle categories, served on Nyckel's own infrastructure — your image stays on Nyckel.

Input
Image

Send an image URL or file to the invoke endpoint; the response is a label with a confidence score.

Make it yours
Adaptable

Clone it, then correct predictions and add your own samples in the console — Nyckel retrains automatically, turning this into a custom model tuned to your data.

More than a demo: this page is one of thousands of pretrained functions on Nyckel, an ML classification platform. You can invoke classifiers by API, review predictions, correct labels, collect samples from production traffic, and promote any pretrained function to a private custom model — without changing your integration.

Where teams use arm vs leg muscle classification

Sports Performance Analysis

This function can be utilized by sports coaches and trainers to assess the specific muscle development in athletes. By identifying the distribution of arm and leg muscles, trainers can tailor training programs to enhance performance based on weaknesses or imbalances.

Rehabilitation Tracking

Physical therapists can employ this image classification function to monitor patients recovering from injuries. By analyzing muscle strength in arms and legs, therapists can adjust rehabilitation protocols and track progress more effectively.

Fitness App Integration

Fitness applications can integrate this classification feature to provide users with personalized workout recommendations. By understanding muscle conditions, users can receive targeted exercises that focus on building strength in either arms or legs.

Health and Wellness Research

Researchers in health and wellness can leverage this technology to study the correlation between muscle development and various health outcomes. By classifying muscle groups, they can gather insights that contribute to ongoing studies in sports science and physical health.

Apparel Design and Fit

Clothing brands specializing in athletic wear can use this function to optimize fit and design based on muscle classification. By understanding the target demographic's physique, they can create products that cater to specific muscle group shapes and sizes, enhancing comfort and performance.

Fitness Device Calibration

Manufacturers of smart fitness devices can incorporate this classification to enhance device calibration for individual users. By understanding a user's muscle makeup, devices can provide more accurate feedback related to calories burned or workout intensity tailored to arm and leg activities.

Personal Training Services

Personal trainers can utilize this function to create more effective and customized workout plans for their clients. By identifying muscle strengths and weaknesses, trainers can ensure balanced training that maximizes results and reduces the risk of injuries.

Common questions

What's the difference between a zero-shot and a Nyckel-trained classifier?

A zero-shot classifier uses a large foundation model's general knowledge to pick between your labels — no task-specific training, so new or edited labels work immediately. A Nyckel-trained classifier has been trained on labeled examples and runs on Nyckel's own infrastructure, which typically makes it faster, cheaper per call, and more accurate on data that resembles its training set. The "Under the hood" section on this page shows which kind this classifier is, and any classifier can be adapted into a trained one by adding your own examples.

How do I know whether this will work for my application?

Honestly: we can't know in advance — it depends on your data stream and how closely it resembles what this classifier has seen. The reliable way to find out is to measure it on your own data: start invoking the classifier with real traffic, or upload and annotate a set of images in the console — make sure they look like your production data, not idealized examples. Nyckel's evaluation metrics then show you exactly how it performs on that data before you rely on it.

What happens when it makes a mistake?

No classifier is perfect, so Nyckel is built around the correction loop: invokes can be captured for review, you confirm or correct predictions in the console, and corrections become training data. Over time the model adapts to your data distribution — accuracy on your traffic improves with use rather than staying fixed.

Do I need training data to get started?

No. This arm vs leg muscle classifier works out of the box — clone it into your console and you'll have your own API endpoint in under a minute. Training data only enters the picture when you want to adapt it: your corrected predictions and uploaded samples improve the model, and you can also edit the label set to match your needs.

What does it cost to try?

Trying the classifier on this page is free with no signup. Cloning it requires a free account, and the free tier covers your first API calls each month — see nyckel.com/pricing for current limits and paid tiers.

Ready to classify arm vs leg muscle at scale?

Add this pretrained classifier to your Nyckel console — you'll get a live API endpoint in under a minute, and a path to a custom model when you need one.