1. Important Safety Information
Before using the leikefitness Ab Exercise Chair, please read and understand all instructions and warnings. Retain this manual for future reference.
- Consult a Physician: Always consult with a healthcare professional before starting any new exercise program, especially if you have pre-existing medical conditions or are taking medication.
- Weight Limit: This exercise chair is designed for users up to 250 lbs (113 kg). Do not exceed this weight limit.
- Proper Assembly: Ensure all parts are correctly assembled and all fasteners are securely tightened before each use. Regularly check for loose components.
- Stable Surface: Use the chair on a flat, stable, and non-slip surface to prevent tipping or movement during exercise.
- Clearance: Maintain adequate clear space around the chair during use to avoid obstructions.
- Children and Pets: Keep children and pets away from the exercise chair during operation.
- Inspect Before Use: Before each workout, inspect the chair for any signs of wear, damage, or loose parts. Do not use if damaged.
- Listen to Your Body: Stop exercising immediately if you experience pain, dizziness, or discomfort.
2. Product Overview
The leikefitness Ab Exercise Chair (Model AB3900) is a versatile fitness equipment designed for core strengthening and inversion therapy. Its lightweight and foldable design allows for easy storage and portability. The chair features a breathable premium mesh seat material for comfort during workouts and is built for stability and safety.

Figure 2.1: The leikefitness Ab Exercise Chair shown in both its unfolded, ready-to-use state and its compact, folded state for storage.
Key features include:
- Abdominal Workout Focus: Specifically designed to target abdominal muscles for effective core strengthening.
- Inversion Therapy Integration: Combines core work with inversion principles to assist with back relief and spinal decompression.
- Foldable Design: Allows for convenient storage under a bed or in a closet, making it ideal for small spaces.
- Breathable Mesh Seat: Provides maximum comfort and ventilation during extended exercise sessions.
- Adjustable Length: Features 4 adjustable length settings to accommodate users of different heights.
- Stable Construction: Engineered for stability and safety during various exercises.

Figure 2.2: Detailed dimensions of the leikefitness Ab Exercise Chair, including its unfolded length, width, height, and folded dimensions (29.52" x 9.84" x 40.15").
3. Assembly and Setup
The leikefitness Ab Exercise Chair is designed for straightforward assembly. Please follow the steps below carefully. It is recommended to have a second person assist with assembly for ease and safety.
- Unpack Components: Carefully remove all parts from the packaging. Verify that all components listed in the included parts list (refer to the separate assembly diagram if provided with your product) are present and undamaged.
- Frame Assembly: Begin by connecting the main frame sections. Ensure that all pre-drilled holes align correctly.
- Secure Fasteners: Insert all bolts, washers, and nuts as indicated in the assembly instructions. Hand-tighten initially.
- Attach Seat and Backrest: Secure the mesh seat and backrest to the frame.
- Install Handles and Pedals: Attach the handles for sit-ups and the foot pedals securely.
- Final Tightening: Once all parts are in place, systematically tighten all fasteners using the provided tools. Do not overtighten.
- Functionality Check: After assembly, test the folding mechanism and adjustability to ensure smooth operation and stability.
Note: If you encounter any misaligned holes or difficulty during assembly, refer to the detailed assembly guide included in your product packaging or contact customer support.
4. Operating Instructions
The leikefitness Ab Exercise Chair offers multiple ways to engage your core and provide spinal relief. Always start slowly and gradually increase intensity as your strength improves.
4.1 Adjusting the Chair Length
The chair features 4 adjustable length settings to accommodate various user heights. To adjust, locate the adjustment pins or knobs on the frame (refer to Figure 2.2 for general location). Pull out the pin, slide the frame to the desired length, and re-insert the pin, ensuring it locks securely into place.
4.2 Abdominal Workouts
For effective abdominal exercises, sit on the chair with your feet secured in the pedals. Use the handles for sit-ups to assist with your movement. Lean back to engage your core, then use your abdominal muscles to pull yourself forward. Focus on controlled movements rather than momentum.

Figure 4.1: Key components of the chair, including the handles for sit-ups and the foot pedals, which are essential for various exercises.
4.3 Inversion and Stretching
The chair's design allows for gentle inversion and stretching to relieve spinal pressure. By leaning back, the chair pivots, allowing your body to stretch and decompress. The ergonomic design supports the natural curve of your body, fitting the waist and back to relieve fatigue.

Figure 4.2: Illustrations of different body positions on the chair, demonstrating how to stretch and take pressure off the spine.

Figure 4.3: Visual representation of the chair's comfortable, ergonomically designed curves that follow the human body's shape, supporting the waist and back.
The 3-way flip joints ensure smooth angle turning and durability during inversion movements.

Figure 4.4: Detail of the strong and durable 3-way flip joints, which allow for smooth adjustments and transitions.
5. Maintenance
Regular maintenance will ensure the longevity and safe operation of your leikefitness Ab Exercise Chair.
- Cleaning: Wipe down the frame and mesh seat with a damp cloth after each use to remove sweat and dust. Use mild soap if necessary, then wipe dry. Do not use abrasive cleaners.
- Check Fasteners: Periodically check all bolts, nuts, and screws to ensure they are tight. Re-tighten as needed to prevent instability and wear.
- Inspect Components: Regularly inspect the mesh material, handles, pedals, and frame for any signs of wear, tears, cracks, or damage. Replace worn or damaged parts immediately.
- Lubrication: If any moving parts (e.g., pivot points, folding mechanisms) become stiff or noisy, apply a small amount of silicone-based lubricant.
- Storage: When not in use, fold the chair and store it in a clean, dry place away from direct sunlight and extreme temperatures.
6. Troubleshooting
If you encounter issues with your leikefitness Ab Exercise Chair, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Chair feels unstable or wobbly. | Loose fasteners; uneven surface. | Ensure all bolts and nuts are securely tightened. Move the chair to a flat, level surface. |
| Difficulty folding or unfolding. | Mechanism stiff or obstructed. | Check for any obstructions. Apply a small amount of silicone lubricant to pivot points if stiff. Ensure adjustment pins are fully disengaged/engaged. |
| Squeaking or grinding noises during use. | Lack of lubrication; loose parts. | Lubricate moving joints. Check and tighten all fasteners. |
| Mesh seat appears stretched or damaged. | Excessive weight; prolonged use; material fatigue. | Ensure user weight is within the specified limit. Contact customer support for replacement parts if necessary. |
If the problem persists after attempting these solutions, please contact leikefitness customer support.
7. Specifications
| Attribute | Detail |
|---|---|
| Brand | leikefitness |
| Model Number | AB3900 |
| Color | Black |
| Material | Polyester+Steel |
| Item Weight | 12.5 Pounds (5.67 kg) |
| Style | Backrest Design |
| Maximum Weight Recommendation | 250 Pounds (113 kg) |
| Product Dimensions (Unfolded) | 72.44 x 29.52 x 48.01 inches (L x W x H) |
| Fold Size | 29.52 x 9.84 x 40.15 inches (L x W x H) |
| Included Components | 1 ab chair |
8. Warranty and Support
The leikefitness Ab Exercise Chair (Model AB3900) comes with a 1-year warranty for brand new products, covering free replacement parts. This warranty covers manufacturing defects and material flaws under normal use and service.
For warranty claims, technical support, or any questions regarding your product, please contact leikefitness customer service through the retailer where you purchased the product or visit the official leikefitness website for contact information.
Please have your model number (AB3900) and proof of purchase ready when contacting support.