Table 3.
Data extraction table for studies investigating lateral bending
| Author and reference | Participants | Methods for stiffness measurements | Results |
|---|---|---|---|
| Gombatto et al. [6] |
• 50 participants • 31 with lower back pain and 19 without • Baseline average data for those without lower back pain: ○ 9 females and 10 males ○ Age: 30.3 (8.5) years ○ Height: 1.69 (0.10) m ○ Mass: 70.2 (15.1) kg ○ BMI: 24.2 (3.0) kg/m2 ○ Baecke Score: 8.9 (1.0) |
• Lateral bending assessed in prone • Pelvis and distal secured to a static table • Participant’s trunk secured to a ‘frictionless’ moveable cradle • EMG electrodes were placed over the external obliques and lumbar erector spinae bilaterally • A passive trial was considered to be any trial where the activity of the muscles opposing the movement did not exceed two percent of the MVC for 0.3 s or more at any point during the trial • A participant’s torso was pulled using a perpendicular force to the line of the body applied to the top of the cradle, measured by a force transducer attached to the pulling cable • A six-camera motion capture system was used to measure the ROM of the lumbar spine with markers located superficial to the first lumbar vertebra and a triad of markers over the second sacral spinous process • Time synchronised force and lumbar spine motion data used to calculate stiffness through range |
Stiffness (Nm/°) values for each quartile 0–25% angle Left: Test 1: 0.23 (0.17) Test 2: 0.25 (0.16) Test 3: 0.26 (0.17) Right: Test 1: 0.26 (0.19) Test 2: 0.29 (0.21) Test 3: 0.31 (0.18) 25–50% angle Left: Test 1: 0.61 (0.29) Test 2: 0.63 (0.28) Test 3: 0.64 (0.31) Right: Test 1: 0.64 (0.36) Test 2: 0.76 (0.49) Test 3: 0.75 (0.39) 50–75% angle Left: Test 1: 1.71 (0.61) Test 2: 1.74 (0.78) Test 3: 1.63 (0.62) Right: Test 1: 1.74 (0.78) Test 2: 2.03 (1.24) Test 3: 1.91 (0.95) 75–100% angle Left: Test 1: 5.19 (2.49) Test 2: 5.25 (3.38) Test 3: 4.79 (2.75) Right: Test 1: 5.14 (2.91) Test 2: 5.78 (3.54) Test 3: 5.07 (2.72) Values averaged across the three tests to establish quartiles for the current study: 1st quartile: 0.27 Nm/° 2nd quartile: 0.67 Nm/° 3rd quartile: 1.79 Nm/° 4th quartile: 5.20 Nm/° |
| Lee and McGill [9] |
• 24 participants • All male • Baseline average data: ○ Age: 22.9 (2.7) years ○ Height: 1.79 (0.06) m ○ Mass: 77.5 (10.8) kg |
• Lateral bending in supine lying • Legs (pelvis and distal) fixed to static platform and torso on ‘frictionless’ moveable platform • Three-dimensional lumbar spine movements measured using electromagnetic tracking system with the source placed over the lower abdomen at a level slightly below the ASIS and the sensor over the xiphoid process • EMG electrodes placed on rectus abdominis, external obliques, internal obliques, latissimus dorsi, upper erector spinae and lower erector spinae • Passivity considered EMG amplitude less than 5% of MVC • A participant’s torso was pulled using a perpendicular force to the line of the body applied to the top of the torso platform, measured by a force transducer • Stiffness was not directly reported; however, normalised (to the maximum applied moment) passive moment was calculated and reported alongside range of movement time normalised |
Results divided into two groups, one inexperienced in core strengthening training and one experienced in it Right bend: Inexperienced group: ROM achieved at varying percentages of total applied moment: 50%: 13.9 (4.8)° 65%: 17.0 (4.3)° 80%: 18.8 (7.7)° 90%: 22.1 (6.3)° 95%: 23.6 (5.7)° 100%: 24.5 (5.5)° Experienced group: ROM achieved at varying percentages of total applied moment: 50%: 14.1 (11.0)° 65%: 13.9 (10.3)° 80%: 17.6 (10.5)° 90%: 20.5 (10.5)° 95%: 21.7 (10.6)° 100%: 22.5 (10.6)° Left bend: Inexperienced group: ROM achieved at varying percentages of total applied moment: 50%: 10.7 (7.2)° 65%: 13.6 (6.4)° 80%: 17.3 (8.9)° 90%: 21.6 (9.4)° 95%: 23.6 (9.8)° 100%: 24.7 (10.0)° Experienced group: ROM achieved at varying percentages of total applied moment: 50%: 13.6 (7.2)° 65%: 15.7 (6.9)° 80%: 16.9 (8.1)° 90%: 19.5 (8.2)° 95%: 21.6 (8.1)° 100%: 22.8 (8.3)° |
| McGill et al. [10] |
• 37 participants • 15 females and 22 males • Female (average): ○ Age: 20.8 (1.8) years ○ Height: 1.65 (0.05) m ○ Mass: 62.3 (8.8) kg • Male (averages): ○ Age: 21.1 (1.2) years ○ Height: 1.77 (0.06) m ○ Mass: 74.9 (7.6) kg |
• Lateral bending in supine lying • Legs (pelvis and distal) fixed to static platform and torso on ‘frictionless’ moveable platform • Three-dimensional lumbar spine movements measured using electromagnetic tracking system with the source placed over the pelvis and the sensor over the xiphoid process • EMG electrodes placed on the spine extensors at the L3 level and abdominal obliques • EMG signal presented as audio feedback and passivity considered when myoelectric silence was achieved throughout • A participant’s torso was pulled using a perpendicular force to the line of the body applied to the top of the torso platform, measured by a force transducer • Torque and rotational displacement data were time synchronised and were plotted against each other • Exponential curves were fitted, and the derivative equation of this curve was used to calculate the stiffness |
Passive stiffness (Nm/°) associated with degree through ROM of right lateral bend: 2 - 0.32 4 - 0.40 6 - 0.49 8 - 0.61 10 - 0.75 12 - 0.93 14 - 1.14 16 - 1.41 18 - 1.75 20 - 2.16 Quartiles calculated for present study: 1st: 0.45 Nm/° 2nd: 1.05 Nm/° 3rd: 2.35 Nm/° 4th: 4.79 Nm/° |
| Voinier et al. [20] |
• 31 participants • Control group baseline average data ○ Age: 30.00 (9.32) years ○ Female: 47% ○ Height: 1.75 (0.10) m ○ Mass: 74.0 (9.9) kg ○ BMI 24.1 (2.0) kg/m2 |
• Lateral bending in supine lying • Legs (pelvis and distal) fixed to static platform and torso on ‘frictionless’ moveable platform • Angular displacement was measured using inertial measurement units, one placed on the pelvis and one on the torso • A participant’s torso was pulled using a perpendicular force to the line of the body applied to the top of the torso platform, measured by a force transducer • A load cell was attached to the moveable platform via a ball and socket joint with an inertial measurement unit attached to it to monitor the angle of pull applied • EMG electrodes placed over the external obliques and lumbar erector spinae muscles • Baseline EMG levels were established once a subject has been placed within the apparatus • Non-passive trials were identified if the EMG level surpassed the level of two standard deviations of this baseline level for more than 10% of the trial • Participants were pulled into the respective movement to be measured while the displacement and force were recorded • The time synchronised torque and displacement data were fit to a double sigmoid curve, the derivative of which described the inverse of stiffness |
Mean neutral zone stiffness (Nm/°) in lateral bending: 0.20 (0.06) Considered to represent the first quartile for the current study |
Where possible, results were converted to Newton metres per degree. Participant data was only presented for those participants relevant to the current review. Stiffness values calculated specifically for this review are clearly identified in the stiffness results column. Numbers in brackets represent standard deviations.
L3 third lumbar vertebrae, m metres, kg kilograms, Nm Newton metre, ROM range of movement, ASIS anterior superior iliac spine, BMI body mass index.