Table 3.
Data extracted from reviewed articles for fractal dimension, where: *—significant differences.
| Study and Quality | Study Group | Age (Years) | Protocol/Conditions | Plate and Sampling Rate (Hz) | Method of Calculation | Results/Findings |
|---|---|---|---|---|---|---|
| Group I: Children/Young/Older Adults | ||||||
| [65] Quality: 10/11 |
Y: 18 OA: 26 |
23.8 ± 1.5 69.8 ± 5.6 |
4 trials (70 s) standing: (1) EO in the normal lighting conditions (NL), (2) EC in the normal lighting conditions (NL), (3) EO in a very low level of illumination (LL), (4) EO in complete darkness (D) |
Kistler 9286AA; 50 Hz | Higuchi’s algorithm |
FD for ML direction (Y/OA) over (0–0.3 s): (1) 1.09 ± 0.03/1.09 ± 0.02 (2) 1.10 ± 0.03/1.10 ± 0.04 (3) 1.09 ± 0.03/1.10 ± 0.04 * (4) 1.10 ± 0.03/1.10 ± 0.03 FD for AP direction (Y/OA) over (0–0.3 s): (1) 1.15 ± 0.05/1.13 ± 0.04 (2) 1.15 ± 0.06/1.14 ± 0.05 (3) 1.14 ± 0.04/1.13 ± 0.04 (4) 1.13 ± 0.05/1.13 ± 0.04 |
| [66] Quality: 10/11 |
Y: 20 OA: 20 |
20.4 ± 1.8 69.4 ± 3.1 | 2 trials (20 s) standing with EO and EC. Each trial repeated 3 times | Pro Balance Master; 100 Hz | Katz’s algorithm [67,68] | EO: FD_Y > FD_OA * FD Reliability: high (ICC ≥ 0.75 and %SEM ≤ 10%) Insensitive to age group differences and fear of falling under both visual conditions |
| [40]SampEn Quality: 10/11 |
Y: 16 | 22–25 | Quiet standing on a soft support surface with EO, 4 times (20 s): before training, 1 min after, 30 min after, 24 h after |
Kistler 9286AA; 100 Hz | Higuchi’s algorithm | Core stability exercises did not cause any changes in FD over time |
| [69] Quality: 10/11 |
Y: 30 | 31.0 ± 6.0 | 6 trials (60 s): Normal standing EO and EC, tense and relaxed states and with both EO and EC |
AMTI Accu-gait; 100 Hz | Katz’s algorithm [67,68] | Conditions (EO/EC): Normal standing: 1.45 ± 0.07/1.48 ± 0.08 Relax: 1.44 ± 0.07/1.46 ± 0.07 Tense: 1.51 ± 0.08/1.55 ± 0.09 |
| Group II: Disabilities/Injures/Diseases | ||||||
| [70] Quality: 9/11 |
PWS: 11 CG: 20 |
34.4 ± 3.7 31.4 ± 9.6 |
Normal standing EO (30 s) | Kistler; 500 Hz | The box-counting method [71] | PWS/CG: 1.58 ± 0.08/1.12 ± 0.08 * |
| [44]SampEn Quality: 10/11 |
CWJ: 11 CG: 11 |
33.3 ± 6.7 33.1 ± 6.8 |
3 trials standing (45 s) with: EO, EC, EO and normal speaking (DT) |
AMTI OR6-5-2000; 200 Hz | Fractal dimension by dispersion analysis based on the standard deviation [72] | All trials FD: CWJ < CG DT task, FD_AP and ML: CWJ < CG * AP: CWJ/CG: 1.06 ± 0.01/1.14 ± 0.01 * ML: CWJ/CG: 1.21 ± 0.01/1.28 ± 0.01 * |
| [46]SampEn Quality: 10/11 |
DS: 10 CG: 11 |
29.8 ± 4.8 28.4 ± 3.9 | 4 trials standing (20s) with: EO and EC on hard surface EO and EC on foam pad |
Kistler 9286AA; 100 Hz | Higuchi’s algorithm | Hard surface AP (DS/CG): EO: 1.46 ± 0.10/1.38 ± 0.08 EC: 1.49 ± 0.08/1.41 ± 0.07 Hard surface ML (DS/CG): EO: 1.41 ± 0.07/1.42 ± 0.06 EC: 1.47 ± 0.05/1.42 ± 0.06 Foam pad AP (DS/CG): EO: 1.53 ± 0.09/1.39 ± 0.08 EC: 1.55 ± 0.08/1.44 ± 0.05 Foam pad ML (DS/CG): EO: 1.52 ± 0.05/1.52 ± 0.06 EC: 1.45 ± 0.06/1.46 ± 0.025 |
| [15] Quality: 10/11 |
FIG: 29 SIG: 28 CG: 16 |
23.2 ± 4.3 21.5 ± 3.3 22.4 ± 1.7 |
3 trials standing (20 s) with EC: SIG—group with acute ankle sprain successfully completed the task on their non-injured limb; FIG—group with acute ankle sprain failed to complete their attempt on their injured limb; CG—group with no current injury successfully completed the task on their non-dominant limb |
AMTI; 100 Hz | Katz’s algorithm [67,68] | FD: FIG < SIG < CG SIG: 1.58 ± 0.06 FIG: 1.54 ± 0.07 CG: 1.64 ± 0.06 |
| [14] Quality: 10/11 |
LAS: 66 CG: 19 | 23.2 ± 4.9 22.5 ± 1.6 |
3 trials standing on single limb (20s) with EO and EC | AMTI; 100 Hz | Katz’s algorithm [67,68] | LAS/CG for involved limb: EO: 1.18 ± 0.14/1.21 ± 0.13 EC: 1.25 ± 0.14/1.39 ± 0.16 LAS/CG for uninvolved limb: EO: 1.15 ± 0.14/1.13 ± 0.15 EC: 1.23 ± 0.14/1.37 ± 0.21 |
| Group III: Athletes | ||||||
| [73] Quality: 10/11 |
BD: 10 CG: 10 |
23.7 ± 2.5 27.6 ± 3.5 |
5 × 30 s | Kistler 9286B; 100 Hz | Katz’s algorithm [67,68] | BD: 1.76 ± 0.06 CG: 1.68 ± 0.07 |
| The minimum value obtained in the reviewed works: 1.06 ± 0.01 [44]. | The maximum value obtained in the reviewed works: 1.76 ± 0.06 [73]. | |||||
Abbreviations: EO—eyes open, EC—eyes closed, AP—anterior–posterior, ML—medial–lateral direction, DT—dual task, Y—young people, OA—older adults, CG—control group, PWS—Prader–Willi syndrome, CWJ—chronic whiplash injury, DS—Down syndrome, LAS—lateral ankle sprain, BD—ballet dancers, FD—fractal dimension, SampEn—study in Table 2, LyE—study in Table 4.