Table 2. Exercise protocols and results of included studies.
| Study | Groups by exercise type | Treatment duration, weeks | Frequency, n/week | Session duration, min | Outcome | Baseline, mean | Post-treatment, mean |
|---|---|---|---|---|---|---|---|
| RCT | |||||||
| Lee, YH. 2010 [28] | Combineda | 10 | 3 | 60 | ALT | 17 U/L | 18 U/L |
| Aerobic | 10 | 3 | 60 | ALT | 53 U/L | 67 U/L | |
| Controlb | N/A | N/A | N/A | ALT | 30 U/L | 38 U/L | |
| Davis 2011 [30] | Combineda | 16 | 2 | 60–90 | HFF | 6.4% | — |
| Controlb | N/A | N/A | N/A | HFF | 8.2% | — | |
| Hasson 2012 [31] | Resistancec | 16 | 2 | 60 | HFF | — | — |
| Controlc,d | N/A | N/A | N/A | HFF | — | — | |
| De Piano 2012 [32] | Aerobic | 52 | 3 | 60 | ALT | 46 U/L | 39 U/L |
| GGT | 27 U/L | 22 U/L | |||||
| Combineda | 52 | 3 | 60 | ALT | 24 U/L | 20 U/L | |
| GGT | 19 U/L | 17 U/L | |||||
| Lee, S. 2012 [33] | Aerobic | 12 | 3 | 60 | MRS | 4.7% | 3.7% |
| Resistance | 12 | 3 | 60 | MRS | 2.9% | 1.8% | |
| Controle | N/A | N/A | N/A | MRS | 2.2% | 3.1% | |
| Lee, S. 2013 [34] | Aerobic | 12 | 3 | 60 | MRS | 2.2% | 1.3% |
| Resistance | 12 | 3 | 60 | MRS | 2.0% | 2.1% | |
| Controlf | N/A | N/A | N/A | MRS | 3.0% | 3.8% | |
| Hay 2016 [35] | High-intensity | 24 | 3 | 30-45g | MRS | 6.4% | 6.1% |
| Moderate-intensity | 24 | 3 | 30-45g | MRS | 5.8% | 7.3% | |
| Controle | N/A | N/A | N/A | MRS | 5.7% | 7.4% | |
| De Lira 2017 [36] | Low-intensity | 12 | 3 | Differedg | ALT | 20 U/L | 20 U/L |
| High-intensity | 12 | 3 | Differedg | ALT | 26 U/L | 23 U/L | |
| Lee, S. 2019 [37] | Aerobic | 24 | 3 | 60 | MRS | 2.5% | 1.9% |
| Resistance | 24 | 3 | 60 | MRS | 3.0% | 2.7% | |
| Combineda | 24 | 3 | 60 | MRS | 2.2% | 1.6% | |
| González-Ruíz 2022 [40] | High-intensity | 24 | 4 | 60 | CAP | 222 dB/m | 202 dB/m |
| ALT | 17 U/L | 16 U/L | |||||
| GGT | 18 U/L | 19 U/L | |||||
| Low-intensity | 24 | 4 | 60 | CAP | 240 dB/m | 234 dB/m | |
| ALT | 22 U/L | 23 U/L | |||||
| GGT | 22 U/L | 24 U/L | |||||
| High- and low-intensity | 24 | 4 | 60 | CAP | 218 dB/m | 202 dB/m | |
| ALT | 15 U/L | 14 U/L | |||||
| GGT | 20 U/L | 18 U/L | |||||
| School-based | 24 | 1 | 60 | CAP | 220 dB/m | 224 dB/m | |
| ALT | 19 U/L | 21 U/L | |||||
| GGT | 16 U/L | 16 U/L | |||||
| Tas 2023 [25] | High-intensity | 4 | 3 | 45 | MRI-PDFF | 5.3% | 5.0% |
| ALT | 20 U/L | 20 U/L | |||||
| Controle | N/A | N/A | N/A | MRI-PDFF | 9.0% | 8.2% | |
| ALT | 30 U/L | 29 U/L | |||||
| NRCT | |||||||
| Labayen 2020 [38] | Combineda | 22 | 3 | 90 | HFF | 5.6% | 4.5% |
| GGT | 17 U/L | 15 U/L | |||||
| Controlh | N/A | N/A | N/A | HFF | 5.2% | 5.2% | |
| GGT | 15 U/L | 15 U/L | |||||
| Iraji 2021 [39] | School-based | 8 | 3 | 50–60 | ALT | 40 U/L | 35 U/L |
| High-intensity | 8 | 3 | 36–40 | ALT | 37 U/L | 33 U/L | |
| Controli | N/A | N/A | N/A | ALT | 37 U/L | 38 U/L | |
| Uncontrolled trial | |||||||
| Bell 2007 [26] | Combineda | 8 | 3 | 60 | ALT | 26 U/L | 26 U/L |
| Van der Heijden 2010(a) [27] | Aerobic | 12 | 4 | 50 | MRSj | 9% | 6% |
| ALT | 39 U/L | 35 U/L | |||||
| Van der Heijden 2010(b) [29] | Resistance | 12 | 2 | 60 | MRS | 9.2% | 9.4% |
See S4 File for detailed descriptions of interventions. Abbreviations: RCT, randomized controlled trial; MRS, magnetic resonance spectroscopy; N/A, not applicable; CAP, controlled attenuation parameter; ALT, alanine transaminase; GGT, gamma‐glutamyltransferase; HFF, hepatic fat fraction;—, no data available; NRCT, non-randomized controlled trial.
aCombined aerobic and resistance training.
bThe control group received no intervention.
cNo baseline values were reported for the intervention groups. The baseline mean hepatic fat fraction for the entire study population was 6.1%.
dThe control group received carbohydrate nutrition education once per week and a total of four motivational interviewing sessions. The resistance exercise group received the same intervention in addition to strength training twice per week.
eThe control group was instructed to maintain their current leisure activities and refrain from beginning an exercise program.
fThe control group was asked not to participate in structured physical activities. All participants were also asked to follow a weight-maintenance diet.
gDiffered based on energy expenditure of 350 kcal
hThe control group attended 45-minute lifestyle sessions and 45-minute psycho-educational sessions once every two weeks for 22 weeks. The exercise group had the same 22-week program in addition to the exercise intervention.
iThe control group did not have a specified intervention.
jValues approximated from bar graph.