Effects of digital-based interventions on muscular strength in adults: a systematic review, meta-analysis and meta-regression of randomized controlled trials with quality of evidence assessment

Figures & data

Figure 1. Flow diagram of the study selection process.

Table 1. Grades of recommendation, Assessment, development and Evaluation (GRADE).

Outcome (muscular strength)	Trials (n)	Participants (n)	SMD	95% LLCI	95% ULCI	I^2	PEDRO score	Quality of evidence (GRADE)
All subjects	55	2346	0.28	0.17	0.39	77	6	moderate quality
Healthy	19	918	0.38	0.12	0.63	85	6	moderate quality
Stroke survivors	12	572	0.34	0.13	0.56	81	6	moderate quality
Neurological disorders	19	683	0.17	0.03	0.32	56	6	moderate quality
Frail population	5	173	0.25	0	0.5	71	5	very low quality
SMD – standardized mean difference; LCI – lower limits of confidence interval; UCI – upper limits of confidence interval

Figure 2. Percentage of studies achieving each Template for Intervention Description and Replication item of the experimental and control groups.

Table 2. Effects of digital-based interventions on measures of muscular strength in general considering different grouping variables.

Independent variables	SMD	SE	95 % CI		Z value	P value	I^2(%)	No. s	Q value and (p) between groups
Cumulated effect (all included studies)
Fixed effects	0.26	0.03	0.21	0.31	10.08	p < 0.001
Random effects	0.28	0.05	0.17	0.39	5.10	p < 0.001	77	162	NA
Cumulated effect (all included studies) - Type of intervention
PC-exergame	0.24	0.06	0.12	0.36	3.88	p < 0.001	81	123	1.62 (0.654)
PC-no-exergame	0.42	0.14	0.15	0.69	3.04	0.002	17	28
VR-exergame	0.47	0.19	0.09	0.85	2.42	0.016	0	2
VR-no-exergame	0.34	0.14	0.06	0.61	2.40	0.017	0	9
Cumulated effect (all included studies) - Type of control group
Passive group	0.40	0.10	0.21	0.59	4.16	p < 0.001	74	52	2.35 (0.125)
Active group	0.22	0.07	0.09	0.35	3.29	0.001	78	110
Cumulated effect (all included studies) - Body Part
Upper body	0.26	0.09	0.09	0.43	3.06	0.002	71.00	57	0.07 (0.784)
Lower body	0.29	0.07	0.15	0.43	4.06	p < 0.001	91.00	83
Asymptomatic subjects
Fixed effects	0.25	0.05	0.15	0.34	5.08	p < 0.001
Random effects	0.38	0.13	0.12	0.63	2.92	0.003	85	38	NA
Type of intervention
PC-exergame	0.35	0.14	0.08	0.62	2.53	0.011	87	33
PC-no-exergame	0.58	0.37	−0.15	1.30	1.56	0.120	0	5	0.32 (0.570)
Type of control group
Passive group	0.39	0.15	0.10	0.68	2.63	0.008	80	30
Active group	0.33	0.28	−0.22	0.89	1.18	0.238	93	8	0.03 (0.858)
Body Part
Upper body	0.28	0.29	−0.29	0.84	0.96	0.337	74	8
Lower body	0.41	0.15	0.12	0.70	2.74	0.006	87	30	0.16 (0.686)
Stroke survivors
Fixed effects	0.36	0.05	0.27	0.45	7.77	p < 0.001
Random effects	0.34	0.11	0.13	0.56	3.08	0.002	81	44	NA
Type of intervention
PC-exergame	0.31	0.15	0.02	0.60	2.10	0.036	88	26
PC-no-exergame	0.40	0.18	0.05	0.74	2.24	0.025	27	20	0.14 (0.706)
Type of control group - NA only 1 study for group 1
Body Part
Upper body	0.37	0.15	0.08	0.65	2.52	0.012	68	29
Lower body	0.31	0.18	−0.05	0.66	1.71	0.087	89	17	0.07 (0.793)
Neurodegenerative diseases patients
Fixed effects	0.18	0.05	0.09	0.27	3.67	p < 0.001
Random effects	0.17	0.07	0.03	0.32	2.30	0.021	56	59	NA
Type of intervention
PC-exergame	0.12	0.09	−0.04	0.29	1.44	0.149	64	45
PC-no-exergame	0.32	0.28	−0.23	0.88	1.13	0.258	0	3
VR-exergame	0.47	0.19	0.09	0.85	2.42	0.016	0	2
VR-no-exergame	0.34	0.14	0.06	0.61	2.40	0.017	0	9	1.99 (0.574)
Type of control group
Passive group	0.38	0.14	0.11	0.66	2.76	0.006	67	16
Active group	0.09	0.09	−0.08	0.27	1.07	0.285	50	43	3.09 (0.079)
Body Part
Upper body	0.21	0.11	0.00	0.42	2.00	0.046	27	30
Lower body	0.13	0.10	−0.07	0.34	1.27	0.204	69	29	0.29 (0.590)
Frail subjects
Fixed effects	0.21	0.07	0.08	0.34	3.21	0.001
Random effects	0.25	0.13	0.00	0.50	1.95	0.051	71	19	NA
Type of intervention – not applicable because only one type of intervention was used among all studies
Type of control group
Passive group	0.47	0.26	−0.05	0.99	1.78	0.075	0	5
Active group	0.18	0.15	−0.11	0.47	1.21	0.226	77	14	0.92 (0.337)
Body Part
Upper body	0.00	0.30	−0.60	0.60	0.00	1.000	7	4
Lower body	0.31	0.15	0.02	0.59	2.12	0.034	76	15	0.83 (0.362)

Table 3. Meta regression for training-related variables and participants intrinsic characteristics to predict digital-based interventions effect on measures of muscular strength in general.

	Coefficient	Standard error	95 % lower CI	95 % upper CI	Z value	p value
Duration of intervention (weeks)	0.031	0.024	−0.016	0.079	1.290	0.196
Weekly frequency (times per week)	0.080	0.047	−0.012	0.172	1.700	0.089
Number of training sessions during whole study	−0.012	0.007	−0.026	0.002	−1.630	0.103
Duration of single training session	0.000	0.004	−0.007	0.007	0.020	0.984
Females to male ratio	−0.002	0.003	−0.008	0.004	−0.690	0.491
Age of participants (years)	0.006	0.004	−0.002	0.014	1.480	0.139

Data availability statement

Data related to this manuscript will be provided based on reasonable request to corresponding author.