Stretch Tracker 4+

Muscle strength & joint health

Nity Vision

Designed for iPad

    • 5.0 • 3 Ratings
    • $1.99



Reduce your joint pain by knowing at what positions it will get strained. Strengthen your hand, leg and abs muscles by knowing how they are stretched during workout.

Stretch Tracker is a fitness plus ergonomics app without any monthly subscription and hidden fees. It is different from any of the fitness app that you have tried in the past. It uses your camera video and computer vision to estimate pose, action, muscle stretch, joint strain and calorie values. Try for yourself and find out how the app evaluates your muscle stretch and joint strain real time without the need for uploading video file or secondary processing.
1. Mount you iPhone/iPad in a stand in the floor so it can see your entire body.
2. Go to the setting page by clicking on the ring of circles.
3. Enter your body weight, height and exercise time in the settings page.
4. Use the front camera to evaluate your muscle stretch and joint strain during exercise.
5. Use the back camera to take exercise data from a recorded video or image played in your TV or PC or real time exercise data for others.
6. Leave the angle threshold values unchanged.
7. Hit the play button and move your arms to get the pose estimation model predict body joints.
Stretch Tracker uses iOS 14 pose estimation model to estimate 19 joint position real time - left wrist, left elbow, left shoulder, neck, right shoulder, right elbow, right wrist, left hip, root, right hip, left knee, left ankle, right knee, right ankle, left ear, left eye, right eye, right ear and nose.
The relative distance, angles between the joints and their positions is used to calculate dynamics of motion such as displacement, speed and calorie burned. Muscle stretch is displayed by different color from blue to red - indicating low stretch to high stretch in units of ft or cm. Joint strain is displayed by different color from blue to red indicating joint angle relative to threshold angle between the joints. The threshold angle values for shoulder, elbow, back and knee can be adjusted in the settings page. The joint color and muscle color (line joining the joints) represent different things so they may not align . While joint color to red indicates bending a joint above its threshold level, the muscle line color represents degree of movement of the joints, which is a measure of amount of exercise and calorie burned.
Based on different joint positions and your exercise type seven different actions are recognized: standing, sitting, hand stretching, squat, lunges and bending. Note that action is recognized real time based on current position between the joints, so if the position changes, the action shows a different value.
Two pie charts one for joint strain and the other for muscle stretch are displayed real time. Muscle stretch pie chart shows hand, legs and abs muscles movement (in ft or cm) in green, yellow and red color segments. Joint strain pie chart shows shoulder, elbow, back and knee joint strain time in seconds in orange, teal, purple and pink color segments.
Calorie is estimated by calculating relative displacement of each muscle segment and their relative weight. Calorie estimation is instantaneous and is displayed in the menu bar in between the two pie charts. The time settings can be changed from the settings page and time is entered in seconds. The time remaining is shown when the play button is pressed.
The fitness summary is saved in a table format that you can use to track exercises in different time. The table shows the date, time, exercise type, calories, abs flex (abdomen stretch) in appropriate units (ft or cm) and the most strained joint during the exercise. The exercise type and joint strain values stored in the table are the most frequent exercise type and joint strain during the time period and these values can be different than current values.

What’s New

Version 1.1

Specified English development language in Xcode binary

Ratings and Reviews

5.0 out of 5
3 Ratings

3 Ratings

christi9901 ,

Great Zumba companion ❤️

Great use of pose recognition in fitness. During my Zumba class I use it every day to see which muscles and joints I am exercising the most at the end of my fitness. This gives me the information to target zones, arms, core and lower body for my next Zumba session.

midwest@user ,

Wonderful fitness app

This app is a great app to improve posture during exercise. I use it to burn fat and measure calories burned. Very simple to use and highly recommend.

Manhattan runner ,

Calorie burner

Wow - unique calories burner app. Now I can just do targeted exercise of belly or arm and know how much calories I am burning. I recommended to my friends and family.

App Privacy

The developer, Nity Vision, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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