Table 2.
Summary of relevant findings for the 30 included articles.
| Author, Year, PEDro Score | Participants, Sample Size | Experimental Conditions | Outcome Measures | Measurement Time Points | Main Results |
|---|---|---|---|---|---|
| Albornoz-Cabello et al. 2020 [15], 9/10 | W (n: 52) and M (n: 32), Adults with patellofemoral pain | EC1: CRET-840 kHz (n: 42) EC2: Control (n: 42) |
1. Pain 2. Neuropathic Pain 3. Patellofemoral pain scale 4. lower limb functional scale 5. Range of movement |
T0 Baseline T1 After intervention |
Pain: lower in EC1 vs. EC2 (6 ± 12.8 vs. 59 ± 16.1 mm). Neuropathic Pain: reduced in EC1 vs. EC2 (0.2 ± 0.52 vs. 3.5 ± 1.83 mm). Patellofemoral pain scale: improved EC1 vs. EC2 (74 ± 13.77 vs. 53 ± 13.49 pts). Lower limb functional scale: improvement in EC1 vs. EC2 (74 ± 14.77 vs. 52 ± 15.84 pts). Range of movement: flexion enhanced in EC1 vs. EC2 (133 ± 7.86 vs. 113 ± 12.58°). |
| Alguacil-Diego et al. 2019 [16], 8/10 | W (n: 14) and M (n: 10) Adults with myofascial chronic neck pain | EC1: CRET-448 kHz (n: 14) EC2: Placebo (n: 10) |
1. Pain 2. Neck Disability Index 3. Range of movement |
T0 Baseline T1 After first intervention T2 After last intervention |
Pain: intragroup in EC1, greater in T0 vs. T1 mean 4.9 cm with a Q1–Q3 dispersion measure of (2.8–6.4) vs. 2.0 cm (1.0–3.0), T0 vs. T2 a mean of 4.9 cm (2.8–6.4) vs. 0.5 cm (0–2.0). Neck Disability Index: in EC1 decrease in T2 vs. T1, 3.0 pts. (2.0–9.0) vs. 10.0 pts. (8.0–12.0) and in EC2 7.0 pts. (6.0–14.5) vs. 14.0 pts. (10.3–20.5). |
| Kumaran et al. 2015 [17], 8/10 | W (n: 9) and M (n: 6), Healthy adults | EC1: CRET-RES448 kHz (n: 15) EC2: CRET-CAP448 kHz (n: 15) |
1. Skin temperature | T0 Baseline T1 After intervention T2 45 min After intervention |
Higher skin temperature in EC1 (T0–T2) vs. EC2 (T0–T2) (33.2 ± 1.4 vs. 31.5 ± 1.4 °C), within EC1 an increase in T1 vs. T0 (35.0 ± 1.2 vs. 31.1 ± 1.0 °C) and T2 vs. T0 (33.2 ± 1.4 vs. 31.1 ± 1.0 °C); within EC2 an increase in T1 vs. T0 (34.3 ± 1.6 vs. 30.9 ± 1.1 °C) and T2 vs. T0 (33.2 ± 1.4 vs. 30.9 ± 1.1 °C). |
| Bretelle et al. 2020 [18], 8/10 | W (n: 60), Adults with postpartum perineal pain | EC1: CRET-500/300 kHz (n: 29) EC2: Placebo (n: 31) |
1. Pain 2. Pain kind 3. Discomfort (Sitting/walking) 4. Paracetamol daily dose |
T0 Baseline T1 2 days After intervention T2 30 days After intervention |
Discomfort in sitting: decrease in EC1 vs. EC2 (12 ± 41.4 vs. 20 ± 64.5%) when comparing T1. |
| Coccetta et al. 2019 [7], 8/10 P | W (n: 47) and M (n: 6), Adults with knee osteoarthritis | EC1: CRET-448 kHz (n: 31) EC2: Placebo (n: 22) |
1. Osteoarthritis Index 2. Muscle strength scale 3. Pain |
T0 Baseline T1 After intervention T2 1 month after intervention T3 3 months after intervention |
Osteoarthritis Index: without significant differences, the minimal clinically important difference is exceeded in EC1 vs. EC2 (32.2 vs. 49.4 pts) in T1, (27 vs. 45.9 pts) T2 and (21.4 vs. 43.9 pts) T3. Pain: decrease in EC1 vs. EC2 in T1 (3.4 * vs. 6 mm), T2 (2.8 * vs. 6.4 mm) and T3 (2.6 * vs. 5.9 mm). Quadriceps strength scale: increase in EC1 vs. EC2 in T2 (4.48 * vs. 3.63 pts) and in T3 (4.58 * vs. 3.72 pts) (* significant compared to T0). |
| Devran et al. 2020 [19], 7/10 | W (n: 33) and M (n: 3), Adults with Trapezius myofascial pain | EC1: CRET-N/A + exercise (n: 18) EC2: Placebo + exercise (n: 18) |
1. Pain 2. Neck Disability Index 3. Range of movement 4. Trigger points. |
T0 Baseline T1 After intervention |
No significant differences between experimental conditions. |
| Kumaran et al. 2019 [20], 7/10 P | W (n: 27) and M (n: 18), Adults with knee osteoarthritis | EC1: CRET-448 kHz + ST (n: 15) EC2: Placebo + ST (n: 15) EC3: ST (n: 15) |
1. Pain 2. Osteoarthritis Index 3. Gait evaluation 4. Range of movement 5. physiological variables |
T0 Baseline T1 After intervention T2 8 Weeks after intervention T3 3 months after intervention |
Pain: an improvement on EC1 vs. EC3, both T0-T1 and T0-T2 (MD 0.82 cm 95% CI 0.32–1.3) and (MD 0.68 cm 95% CI 0.10–1.3) respectively, as well as an improvement in EC1 vs. EC2 (T0-T1) (MD 0.79 cm 95% CI 0.29–1.3). Osteoarthritis Index: improvement in CS1 vs. EC3 (T0-T1) (MD 1.3 pts. 95% CI 0.02–2.6). |
| Clijsen et al. 2020 [6], 7/10 | W (n: 4) and M (n: 6), Healthy adults | EC1: CRET-RES448 kHz (n: 10) EC2: CRET-CAP448 kHz (n: 10) EC3: Placebo (n: 10) |
1. Skin perfusion 2. Intramuscular blood flow (distal/proximal) 3. Heart rate 4. Blood pressure 5. Skin temperature |
T0 Baseline T1 After intervention T2 2 min after intervention T3 10 min after intervention |
Skin perfusion: lower in EC3 vs. EC2 (−24.8 (16.8) vs. −3.97 (22.01) %) in turn, lower in EC2 vs. EC1 (−3.97 (22.01) vs. 23.1 (54.4) %). Distal intramuscular blood flow: greater difference in EC1 (T0-T3) vs. EC3 (T0-T1) (2.06 (3.3) vs. 0.01 (0.7) %) as well as in EC1 (T0-T3) vs. EC2 (T0-T2) (2.06 (3.3) vs. 0.79 (3.3) %), higher skin temperature in EC1 (T0-T3) vs. EC3 (T0-T3) (2.8 (2) vs. −2.3 (1.5) °C). (Average (Q1–Q3)). |
| Kumaran et al. 2018 [21], 7/10 | W (n: 10) and M (n: 7), Healthy adults | EC1: CRET-448 kHz (n: 17) EC2: Placebo (n: 17) EC3: Control (n: 17) CE4: PSWT (n: 15) |
1. Skin temperature 2. Skin perfusion 3. Neural conduction velocity |
T0 Baseline T1 After intervention T2 20 min after intervention |
Skin temperature: significant increase in EC1 vs. the rest of the groups. Skin irrigation: significant increase in EC1 vs. EC2, EC1 vs. EC3, and EC1 vs. CE4. (unspecified results). |
| Pavone et al. 2017 [22], 7/10 | M, Adults with Peyronie’s disease (n: 96) | EC1: CRET-250/500 kHz (n: 64) EC2: Placebo (n: 32) |
1. Pain 2. Degree of penile curvature 3. Erectile dysfunction questionnaire |
T0 Baseline T1 After intervention T2 3 months after intervention |
Pain: improvement in EC1 from T0 to T1 (2 points on the VAS scale in 58% of subjects) (Results not specified). |
| Noites et al. 2019 [23], 7/10 | W, Healthy adults (n:30) | EC1: CRET-480/500 kHz + exercise (n: 15) EC2: Placebo + exercise (n: 15) |
1. Lipid profile | T0 Baseline T1 After intervention |
Lipid profile without differences between EC1 vs. EC2, changes only in glycerin within EC1 and in EC2 separately, comparing T0 vs. T1 (0.06 ± 0.03 vs. 0.10 ± 0.06 mmol/L and 0.04 ± 0.01 0.07 ± 0.03 mmol/L, respectively). |
| Vale et al. 2020 [24], 7/10 | W, Healthy adults (n: 28) | EC1: CRET-480/500 kHz + exercise (n: 14) EC2: Placebo + exercise (n: 14) |
1. Bodyweight 2. Body mass index 3. Waist circumference 4. Subcutaneous adipose tissue thickness 5. Abdominal fold |
T0 Baseline T1 After intervention |
Body mass index: within EC1 lower in T1 vs. T0 (22.70 ± 2.57 vs. 23.00 ± 2.55 kg/cm3). Waist circumference: in EC1 decreases in T1 vs. T0 (78.39 ± 9.52 vs. 80.21 ± 10.21 cm); this difference is greater vs. difference in EC2. Adipose tissue thickness: within EC1 decreases in T1 vs. T0 (12.51 ± 6.40 vs. 10.26 ± 5.44 mm) greater difference vs. difference in EC2. Abdominal fold: decreased in EC1 vs. EC2 (16.32 ± 4.98 vs. 18.01 ± 5 mm). |
| Maretti et al. 2020 [25], 6/10 | M, Adults with Peyronie’s disease (n = 66) | EC1: CRET-500 kHz (n: 32) EC2: CRET-500 kHz + hydro electrophoresis de Verapamil (n: 34) |
1. Pain 2. Degree of penile curvature 3. Erectile dysfunction questionnaire |
T0 Baseline T1 After intervention T2 3 months after intervention |
Pain: Improved EC2 vs. EC1 (0.74 ± 0.11 vs. 1.82 ± 0.11 cm) in T2. Erectile dysfunction questionaire: EC2 improvement vs. EC1 (27.83 ± 0.18 vs. 26.56 ± 0.25 pts) in T2. Degree of penile curvature: Less in EC2 vs. EC1 (9.4 ± 0.76 vs. 12.7 ± 0. 77°). All significant when comparing T2 vs. T0 (intragroup). |
| Tashiro et al. 2017 [26], 6/10 | M, Healthy adults (n: 13) | EC1: CRET-448 kHz (n: 13) EC2: Placebo (n: 13) EC3: Hot-Pack (n: 13) |
1. Hemoglobin 2. Temperature at 10/20 mm deep |
T0 Baseline T1 periods of 5 min during half an hour |
Hemoglobin: increase in EC1 vs. EC2 (98.1 umol/L (79.8–108.9) vs. 92.6 umol/L (78.3–99.5), Mean and ranges), as well as EC1 vs. EC3 (98.1 umol/L (79.8–108.9) vs. 92.3 umol/L (69.8–103.8)), temperature at 20 mm: increase of EC1 vs. EC2 (36.8 °C (35.6–37.5) vs. 35.0 °C (34.0–36.3)), as well as EC1 vs. EC3 (36.8 °C (35.6–37.5) vs. 36.5 °C (34.8–37.1)). |
| Casa-Almeida et al. 2011 [27], 5/10 | W, Adults with edematous fibro sclerotic Panniculopaty (n: 27) | EC1: local CRET-1 MHz (n: 27) EC2: segmented CRET-1 MHz (n: 27) |
1. Clinical classification of cellulite severity 2. Perimeters 3. Physiological variables |
T0 Baseline T1 After 10th intervention T2 After 20th intervention |
Severity classification: no differences between groups, total score improves within EC1 and EC2 when comparing T2 vs. T0 (4.32 ± 2.6 vs. 7.35 ± 2.4 pts and 3.96 ± 2.9 vs. 7.03 ± 2.7 pts, respectively). Perimeter: no differences between groups, within-group EC1 decreases T2 vs. T0 of the iliac crest (75.93 ± 1.1 vs. 77.87 ± 1.1 mm), of ASIS (88.63 ± 1.0 vs. 90.07 ± 1.1 mm) and greater trochanter (96.23 ± 1.2 vs. 97.68 ± 1.2 mm), in EC2 differences in the rest of the perimeters when comparing T2 vs. T0. Weight: decreases in T2 vs. T0 (Results not specified). |
| Fousekis et al. 2020 [28], 5/10 | M, Healthy adults (n: 10) | EC1: CRET-448 kHz (n: 10) EC2: Placebo (n: 10) EC3: CRET-448 kHz + fascia tool (n: 10) CE4: Placebo (n: 10) |
1. Skin temperature | T0 Baseline T1 After intervention |
Skin temperature: within EC1 and EC3, a significant increase in temperature, Maintenance of this temperature: EC1 vs. EC2 significantly different (39.9 vs. 34.9 °C), EC1 vs. CE4 (39.9 vs. 35.7 °C), likewise EC3 vs. EC2 significantly different (39.7 vs. 34.9 °C) and EC3 vs. CE4 (39.7 vs. 35.7 °C). |
| Duñabeitia et al. 2018 [29], 5/10 | W, Recreational adult runners (n: 14) | EC1: CRET-0.8/1.2 MHz (n: 14) EC2: Control (n: 14) |
1. Physiological variables 2. Biomechanical variables (in four tests 10, 12, 14 and 16 km/h) |
T0 24 h after excercise T1 72 h after excercise |
Biomechanical variables: increase in stride length: in EC1 vs. EC2 (123.39 ± 5.81 vs. 121.91 ± 5.12 cm) at 12 km/h, (139.88 ± 6.47 vs. 138.31 ± 6.57 cm) at 14 km/h and (154.59 ± 8.12 vs. 152.35 ± 9.7 cm) at 16 km/h, stride angle: increase in EC1 vs. EC2 (0.94 ± 0.43 vs. 0.73 ± 0.39°) at 12 km/h, (139.88 ± 6.47 vs. 138.31 ± 6.57°) at 14 km/h (1.91 ± 0.50 vs. 2.01 ± 0.64°) at 16 km/h, stride height: increase in EC1 vs. EC2 (0.90 ± 0.34 vs. 0.85 ± 0.36 cm) at 14 km/h and (1.30 ± 0.38 vs. 1.36 ± 0.44 cm) at 16 km/h, Stride frequency: lower in EC1 vs. EC2 (2.78 ± 0.12 vs. 2.83 ± 0.14 Hz) at 14 km/h and (2.83 ± 0.23 vs. 2.89 ± 0.15 Hz), as well as an increase in these variables when comparing intragroup in EC1. |
| Rodriguez-Sanz et al. 2017 [30], 4/10 | N/A (n:20) Adults with low back and pelvic Pain | EC1: CRET-N/A (n: 10) EC2: Placebo (n: 10) |
1. Pain 2. Pain threshold by pressure 3. Physical disability test due to low back pain |
T0 Baseline T1 After intervention T2 4 weeks after intervention |
There are no significant differences between the groups; in EC1, there is a difference in Pain between T2-T0 greater than the clinically relevant one (2.1 ± 2.1 cm), while in EC2, it is less (0.84 ± 0.7. 2 cm). |
| Cau et al. 2019 [31], 4/10 P | W, Adults with obesity and lymphedema (n: 48) | EC1: CRET-0.8/1.2 MHz + ST (n:12) EC2: Pressotherapy + ST (n: 12) EC3: LD+ ST (n: 12) CE4: ST (n: 12) |
1. Pain 2. Gait evaluation 3. Volume of lower limb |
T0 Baseline T1 After intervention |
Pain: EC1 improvement in T1 vs. T0 (47.2 ± 24.2 vs. 73.9 ± 21.7 mm). Gait evaluation: decreased EC1 in T1 vs. T0 (13.3 ± 8.1 vs. 21.8 ± 19.7 s). Lower limb volume: decrease in total volume within EC1 in T1 vs. T0 (9.4 ± 2.8 vs. 9.7 ± 2.8 cubic dm) as well as the thigh volume (3.3 ± 1.2 vs. 3.5 ± 1.3 cubic dm), Thigh circumference: decrease in EC1 between T1 vs. T0 (712.8 ± 106.9 vs. 722.35 ± 191.2 mm). |
| Notarnicola et al. 2017 [8], 4/10 | W (n: 43) and M (n: 17), Adults with low back pain | EC1: CRET-450/600 kHz (n: 30) EC2: Laser (n: 30) |
1. Pain 2. Disability index 3. Disability questionnaire |
T0 Baseline T1 After intervention T2 1 month after intervention T3 2 months after intervention |
Pain: decrease in EC1 vs. EC2 (1.6 ± 0.9 vs. 3.5 ± 2.5 mm) in T2 and (0.8 ± 0.7 vs. 4.2 ± 2.4 mm) in T3, disability index: lower in EC1 vs. EC2 (9.4 ± 14.6 vs. 26.8 ± 19.8 pts) in T2 and (6.0 ± 2.7 vs. 26.0 ± 18.6 pts) T3, disability questionnaire: decrease in EC1 vs. EC2 (4.7 ± 2.5 vs. 8.8 ± 6.3 pts) in T1, (2.0 ± 1.9 vs. 9.1 ± 7.0 pts) in T2 and (1.5 ± 1.4 vs. 8.6 ± 6.5 pts) in T3. |
| Stagi et al. 2008 [32], 3/10 | N/A (n: 30) Adults with low back pain | EC1: CRET-485 kHz + massotherapy (n: 15) EC2: Placebo + massotherapy (n: 15) |
1. Pain 2. Physical disability test due to low back pain 3. Quality of life questionnaire 4. Medicine intake |
T0 Baseline T1 After 4 th intervention T2 After 8 th intervention T3 3 month after intervention T4 6 month after intervention |
Pain: difference in its perception and management, improvement within EC1 when comparing T5 vs. T0 (unspecified data). No significant difference between groups. |
| Sanguedolce et al. 2019 [9], 3/10 | W (n: 14) and M (n: 16), Adults with rotator cuff tendinitis | EC1: TENS + iontophoresis + laser + ultrasound + reeducation (n:15) EC2: CRET-N/A + reeducation (n: 15) |
1. Pain 2. Specific shoulder test 3. Functional Scale |
T0 Baseline T1 4 weeks after intervention T2 8 weeks after intervention |
Pain: unspecified statistical contrasts, EC2 vs. CS1 in T1 (5.3 vs. 6.5 cm) and in T2 (3.7 vs. 5 cm). |
| Takahashi et al. 2000 [33] | W (n: 17) and M (n: 5), Adults with cervical omo-brachial Pain | EC1: CRET-CAP50/651 kHz (n: 22) | 1. Severity of symptoms 2. Skin temperature 3. Safety |
T0 Baseline T1 After intervention T2 15 min after intervention |
Symptom severity: a significant decrease in T1 vs. T0 (6.32 ± 3.36 vs. 9.5 ± 4.75 pts). Skin temperature: significant increase in T2 vs. T0 (30.6–31.3 vs. 29.3–29.8 °C) and T1 vs. T0 (29.7–28.8 vs. 29.3–29.8 °C). Safety: no adverse effect. |
| Ibánez-Vera et al. 2019 [34] | W (n: 13) and M (n: 6), Constipation in adults with Intellectual Developmental Disorders | EC1: CRET-850 kHz + Vacuum therapy (n: 19) | 1. Number of stools 2. Episodes of irritability 3. Scale fecal characteristics |
T0 During intervention (14 days) T1 After intervention (14 days) |
Number of stools: increase in T1 vs. T0 (10.23 ± 2.32 vs. 8.85 ± 2.34), irritability episodes: decrease in T1 vs. T0 (14 ± 4.26 vs. 15.95 ± 7.05), the scale of characteristics: better in T1 vs. T0 (2.47 ± 0.61 vs. 1.89 ± 0.65 points) significantly. |
| Ganzit et al. 2000 [35] | W (n: 3) and M (n: 27), Adult athletes with various muscle injuries | EC1: CRET-500 kHz (grade I, II, III muscle injury) (n: 30) | 1. Injury resolution by ultrasound image (Days/Sessions) | T0 Baseline T1 After intervention T2 2 weeks after intervention |
Injury resolution: by group mean difference, Grade-I: 5.1 sessions in 8 days, Grade-II: 8.6 sessions in 14 days and Grade-III: 11.7 sessions in 19 days. |
| Sodré et al. 2019 [36] | M, Adults with urinary incontinence after radical prostatectomy (n: 10) | EC1: CRET-0.5/1 MHz (n: 10) | 1. Incontinence questionnaire (Short form/Overactive bladder) 2. Loss test 3. Global visual incontinence scale |
T0 Baseline T1 After intervention |
Incontinence questionnaire: improvement T1 vs. T0 in overactive bladder (6.0 pts. (4.7–8.7) vs. 5.0 pts. (0.7–6.7), mean and standard deviation). Loss test: improvement in T1 vs. T0 (2.0 g (0.0–9.0) vs. 6.5 g (1.7–50.0)), visual incontinence scale: decrease in T1 vs. T0 (4.0 cm (1.7–5.0) vs. 7.0 cm (5.0–8.5)). |
| Rafaetá et al. 2007 [37] | W (n: 15) and M (n: 5), adults with cervicalgia | EC1: CRET-N/A (n: 20) | 1. Pain 2. Cervicalgia questionnaire 3. Visual Scale of improvement |
T0 Baseline T1 After intervention T2 2 months after intervention |
Pain: Unspecified statistical contrasts, T1 vs. T0 (2.79 vs. 6.63 cm) and in T2 vs. T0 (2.55 vs. 6.63 cm). Questionnaire: without statistical contrast, decreased T1 vs. T0 (16.67 vs. 37.95%) and T2 vs. T0 (12.54 vs. 37.95%). |
| Takahashi et al. 1999 [38] | W (n: 27) and M (n: 10), Adults with low back pain | EC1: CRET-CAP50/650 kHz (n: 37) | 1. Severity of symptoms 2. Skin temperature 3. Safety |
T0 Baseline T1 After intervention T2 15 min after intervention |
Symptom severity: a significant decrease in T1 vs. T0 (6.2 ± 4.0 vs. 11.5 ± 4.9 pts). Skin temperature: significant increase in T2 vs. T0 (31.1–31.3 vs. 29.2–29.5 °C) and T1 vs. T0 (30.2–30.5 vs. 29.2–29.5 °C). Safety: no adverse effect. |
| Osti et al. 2014 [39] | W (n: 30) and M (n: 36), Adults with low back pain | EC1: Laser + CRET-450/600 kHz (n: 66) | 1. Pain 2. Physical disability test due to low back pain |
T0 Baseline T1 8 weeks after intervention |
Pain: decreases in T1 vs. T0 (2.63 ± 2.74 vs. 8.1 ± 1.58 cm), disability test: decrease in T1 vs. T0 (23.5 (± 19.8) vs. 53.0 (± 13.0) pts.), even when separating the group by extension of pain, both variables were still significant. |
| Fernández-Cuadros et al. 2020 [40] | W, Adults with chronic pelvic Pain and dyspareunia (n: 37) | EC1: CRET-448 kHz + Biofeedback + PFE (n: 37) | 1. Pain 2. Muscle strength |
T0 Baseline T1 After intervention |
Pain: decrease in T1 vs. T0 (3.75 ± 2.21 vs. 7.27 ± 1.34 cm), muscle strength: evidence of increased maximum strength in T1 vs. T0 (35.35 ± 20.4 vs. 25.56 ± 15.9 mmHg) as well as the mean force (7.18 ± 4.46 vs. 4.86 ± 3.53 mmHg). |