Table 3.
Evidence of effect in studies: outcomes measures
| Ref. | Outcome measure | Tilt away from vertical | Mean change with tilt from vertical | Significance level reported (P = 0.05) |
|---|---|---|---|---|
| Interface loading | ||||
| 5, 20 | Maximum pressure under ischial tuberosities | 20° posterior tilt | −11% | Yes [in ref. 20] |
| Tangential shear force through seat | −85% | Yes [in ref. 20] | ||
| 6 | Pressure at ischial tuberosities and sacrum (averaged over the 3 locations, mean over 1 minute of measurements) | 45° posterior tilt | −34% | Not reported (2 participants) |
| 7 | Maximum interface pressure | 25° posterior tilt | −22% | Yes (P < 0.01) |
| Mean interface pressure (mean of 2 measurements) | −8% | No | ||
| 15 | Pressure under ischial tuberosity (side of highest pressure, mean of 10 measurements) | 45° posterior tilt | −33% | Yes (P < 0.001) |
| 16 | Maximum pressure under right ischial tuberosity; average for 3 cushion inflation pressures, 3 measurements at each | 20° posterior tilt | −5% | Yes (P = 0.012) |
| 25 | Pressure over ischial tuberosities, mean over 1 minute of measurements | 35° posterior tilt | −27% | No |
| Posture and stability | ||||
| 4 | Thoraco-lumbar distance | 25° posterior tilt | +3% | No |
| Cervico-thoracic distance | −36% | Yes | ||
| 21 | Thigh length (indirect measure of pelvic tilt), shoulder position and head orientation from photographs | 14° posterior tilt | −1.1−1.6 cm, +6.5°, respectively | No |
| 28 | Mean displacement of the head,# shoulder,# hip knee, ankle | 5° posterior tilt, 5° anterior tilt | Variable. Maximum change was 4 cm increase | Yes# (in some segments with anterior tilt) |
| 26 | Sagittal pelvic orientation | 10° anterior tilt | <2° more anterior. Variable | No |
| 18 | Distance from pelvis to spinous process | 30° anterior tilt | −8% | Yes |
| 23 | Sitting height | 15° anterior tilt | −0.21 cm | No |
| Radius of head position (stability) | −0.97 cm | Yes (P = 0.037) | ||
| Muscle activity | ||||
| 17 | EMG (lumbar erector spinae) | 15° posterior tilt | + 37% | No |
| 19 | EMG (erector spinae at T3, T9 and L3, serratus anterior,† oblique abdominals,† pectoralis major,† latissumus dorsi,† trapezius) | 12° posterior tilt | Variable. Increased in some groups. Decrease in others | Yes† in some muscles and injury levels, no for others |
| 27 | EMG (iliocostalis lumborum, adductor magnus and gastrocnemius) | 30° posterior tilt | +51, +19, +1%, respectively | Yes (back and hips) |
| 23 | EMG (erector spinae, average from four bilateral paraspinal sites) | 15° anterior tilt | +73% | Not reported |
| 26 | EMG (erector spinae at T3,* T9* and L3,* oblique abdominals, serratus anterior, pectoralis major, latissumus dorsi, trapezius*) | 10° anterior tilt | Up to −50% depending on anatomical location and level of injury | Yes* in some muscles and injury levels, no for others |
| Respiratory function | ||||
| 4 | Forced vital capacity | 25° posterior tilt | +20% | Yes (P < 0.001) |
| Chest expansion | +7% | Yes (P = 0.014) | ||
| 29 | Tidal volume, respiration rate, minute ventilation | 10° anterior tilt | +12, +3, +3%, respectively | No |
| Other functional activity | ||||
| 19 | Maximum unsupported forward reach distance | 12° posterior tilt | <5 cm difference | No |
| 3 | Time with head directed to activity | 15° posterior tilt | +22% | Not reported |
| 4 | Voice volume | 25° posterior tilt | −0.1% | No |
| Perceived exertion on Borg's scale of 6–20 | −4.96% | No | ||
| 24 | Timed switch use with upper extremity | 30° posterior 15° anterior tilt | +39%, +44%, respectively | Yes Yes |
| 28 | Upper extremity activity (6 timed tasks) | 5° posterior 5° anterior tilt | Improved in 1 of 6 tasks in each tilt condition | Yes for only 1 task No for 5 tasks. |
| 22 | Time with head upright | 0–15° anterior tilt (mean 8°) | +93% mean duration | Yes (P = 0.001) |
| Sitting assessment score 5–20 | +56% median score | Yes (P = 0.001) | ||
| Number of pathological movements | −75% median number | Yes (P = 0.002) | ||