Device Requirements:
| Design Requirement | Design Specification | Verification | Validation |
|---|---|---|---|
| 1. The device will restrict motion of the arm to the scapular plane (defined as 30-45⁰ anterior to coronal plane). | 1.1. The scapular plane component of the device will be 37.5⁰+1⁰, -7.5⁰ anterior to coronal plane. | 1.1. Ten measurements of the angle between the scapular plane component of the device and the coronal plane will be measured using a goniometer. The average and standard deviation will be calculated. For acceptance, ±3σ must fall within the specifications. | 1.1. Ten measurements of the angle between the center of the test subject's arm and the coronal plane will be measured using a goniometer. The average and standard deviation will be calculated. For acceptance, ±3σ must fall within the specifications. |
| 2. The device will move in external rotation. | 2.1. The arm must be abducted 90⁰ ± 10⁰ in the scapular plane. 2.2. External rotation must be performed in a range of (90⁰- 180⁰) ± 10⁰ . | 2.1. On the device, the angle of abduction will be set to the specification. Ten measurements of the angle will be measured using a goniometer. The average and standard deviations will be calculated. For acceptance, ±3σ must fall within the specifications. 2.2. On the device, the angle of external rotation will be set to the minimum and maximum specification range values and measured using a goniometer at each angle using the same parameters in 2.1. | 2.1. On the device, the angle of abduction will be set to the specification. Ten measurements of the angle between the test subject's side and center of abducted arm will be measured using a goniometer. The average and standard deviations will be calculated. For acceptance, ±3σ must fall within the specifications. 2.2. The test subject will move the device from the minimum to maximum allowable angles within these ROM and these angles will be measured using a goniometer with the same parameters in 2.1. |
| 3. The device will move in abduction. | 3.1. Abduction must be performed in range of motion of (0⁰-120⁰) ± 10⁰. | 3.1. On the device, the angle of abduction will be set to the minimum and maximum specification range values and measured using a goniometer at each angle. The average and standard deviations will be calculated. For acceptance, ±3σ must fall within the specifications. | 3.1. The test subject will move the device from the minimum to maximum allowable angles within this ROM and these angles will be measured using a goniometer with the same parameters in 2.1. |
| 4. The device will provide variable resistance training. | 4.1. Resistance will vary from 2.0 ± 0.5 lb to 7.0 ± 0.5 lb. | 4.1. Stiffness will be experimentally determined for each resistive component according to the k value for resistance requirements of Theraband resistance bands at 100% elongation. A variation of loads will be applied to the resistive component. The change in length will be measured and compared against the force produced by the load. This will generate a plot and the slope (or stiffness) will be calculated. The average and standard deviation for the stiffness of each resistive component will be calculated and ±3σ must fall within the specifications for acceptance criteria. | N/A |
| 5. The device must fit the average range of human sizes. | 5.1. The device must fit the average length of a shoulder (13.7 ± 1.3 cm). 5.2. The device must fit the average torso (circumference of 57.2 cm - 99.1 cm) ± 1.0 cm. 5.3. The device must fit the average wrist. (circumference of 14.0 cm - 22.6 cm) ± 1.0 cm. 5.4. The device must fit the average length of the brachium (32.4 - 43.1 cm) ± 1.0 cm. 5.5. The device must fit the average length of the anti-brachium (24.6 cm - 26.4 cm) ± 1.0 cm. Note: Ranges for 5.2-5.5 due to adjustable property of component. | 5.1, 4, 5. Ten measurements will be obtained for the length of the shoulder, brachium and anti-brachium components of the device using a ruler. The average and standard deviation will be calculated. For acceptance, ±3σ must fall within the specifications. 5.2-3. Same parameter as above will be used for measurements of wrist and torso using a tape measure. | 5.1-5. The device will be tested on multiple subjects and the range of fit will be examined. The ranges should fit 90% of the human subjects. |
| 6. The device must be comfortable. | 6.1. The device must be worn for up to 30 minutes. | N/A | 6.1. Test subjects will wear the device for at least 30 minutes and comfort will be ranked from 1 (very uncomfortable) to 5 (very comfortable) |
| 7. The device will not significantly increase exercise time. | 7.1. The device will not increase exercise time by more than 10%. | N/A | 7.1. The time it takes to don and doff the device will be recorded per test subject. |
| 8. The system actively records the degree of motion the user achieves. | 8.1. A sensor must measure angles from (0⁰ - 180⁰) ± 10⁰. | 8.1 On the device, the angles of abduction and internal rotation will be set to the minimum and maximum angle values and measured. Ten measurements will be taken for each angle both using a goniometer and from the output of the device. A paired t-test will be used to determine of the if the values are statistically the same. | N/A |
| 9. The system must have a portable power source. | 9.1 A 9V battery powers the system. | N/A | 9.1. Device will be checked to determine if a 9V battery is present. |
| 10. The system provides a real-time, visual representation of the degree of motion. | 10.1. A wireless module transmits data between the microcontroller and a smartphone. 10.2 An application on the smartphone plots angle measurements in real time. | N/A | 10.1-2. The test subject will perform the specified exercises and the smartphone will be examined to see if data is being plotted in real time. |
| 11. The system must store the average effort per trial. | 11.1 The application on the smartphone must overwrite the time, date, and average effort per trial. | N/A | 11.1. The test subject will perform two sets of the specified exercise and the smartphone will be observed to examine if the average effort is overwritten for second trial. |
Justifications:
1.1. The scapular plane of motion is used for rehabilitation because it facilitates optimal muscle forces. Excessive motion in the coronal plane may cause overload on the anterior cuff tendons. There is also a greater external rotatory force and smaller compressive force in this plane.
2.1-2. Values obtained from the International Journal of Sports Physical Therapy.
3.1. Values obtained from appropriate literature.
4.1-2. Justified during testing.
5.1-5: Values obtained from appropriate literature.
6.1. Typical physical therapy sessions about 30 minutes.
7.1. Justified during testing.
8.1. Recommended by TCNJ Trainer, Megan Guicheteau.
9.1. Most cost effective solution.
10.1-2. The user can easily view their progress.
11.1. The user can monitor day-to-day progress.