Effect of Home Exercise Training in Patients with Nonspecific Low-Back Pain: A Systematic Review and Meta-Analysis

Abstract

Background:
Exercise therapy is recommended to treat non-specific low back pain (LBP). Home-based exercises are promising way to mitigate the lack of availability of exercise centers. In this paper, we conducted a systemic review and meta-analysis on the effects of home-based exercise on pain and functional limitation in LBP.

Method:
PubMed, Cochrane, Embase and ScienceDirect were searched until April 20th, 2021. In order to be selected, studies needed to report the pain and functional limitation of patients before and after home-based exercise or after exercise both in a center and at-home. Random-effect meta-analyses and meta-regressions were conducted.

Results:
We included 33 studies and 9588 patients. We found that pain intensity decreased in the exclusive home exercise group (Effect size = -0.89. 95% CI -0.99 to -0.80) and in the group which conducted exercise both at-home and at another setting (-0.73. -0.86 to -0.59). Similarly, functional limitation also decreased in both groups (-0.75. -0.91 to -0.60, and -0.70, -0.92 to -0.48, respectively). Relaxation and postural exercise seemed to be ineffective in decreasing pain intensity, whereas trunk, pelvic or leg stretching decreased pain intensity. Yoga improved functional limitation. Supervised training was the most effective method to improve pain intensity. Insufficient data precluded robust conclusions around the duration and frequency of the sessions and program.

Conclusion:
Home-based exercise training improved pain intensity and functional limitation parameters in LBP.

Full text

International Journal of
Environmental Research
and Public Health
Systematic Review
Effect of Home Exercise Training in Patients with Nonspecific
Low-Back Pain: A Systematic Review and Meta-Analysis
ChloéQuentin 1, Reza Bagheri 2, Ukadike C. Ugbolue 3, Emmanuel Coudeyre 4, Carole Pélissier 5,6,
Alexis Descatha 7,8, Thibault Menini 9, Jean-Baptiste Bouillon-Minois 10, * and Frédéric Dutheil 11


Citation: Quentin, C.; Bagheri, R.;
Ugbolue, U.C.; Coudeyre, E.;
Pélissier, C.; Descatha, A.; Menini, T.;
Bouillon-Minois, J.-B.; Dutheil, F.
Effect of Home Exercise Training in
Patients with Nonspecific Low-Back
Pain: A Systematic Review and
Meta-Analysis. Int. J. Environ. Res.
Public Health 2021,18, 8430.
https://doi.org/10.3390/
ijerph18168430
Academic Editors: Sergio Iavicoli,
Vincenzo Denaro, Gianluca Vadalà
and Fabrizio Russo
Received: 28 June 2021
Accepted: 5 August 2021
Published: 10 August 2021
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
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iations.
Copyright: © 2021 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
1CHU Clermont-Ferrand, Department of Family Medicine, Faculty of Medicine,
UniversitéClermont Auvergne, F-63000 Clermont-Ferrand, France; chloe.quentin@etu.uca.fr
2Department of Exercise Physiology, University of Isfahan, Isfahan 81746-73441, Iran; will.fivb@yahoo.com
3School of Health and Life Sciences, Institute for Clinical Exercise & Health Science,
University of the West of Scotland, Glasgow G720LH, UK; u.ugbolue@uws.ac.uk
4Physical Medicine and Rehabilitation, INRAE, UNH, CHU Clermont-Ferrand,
UniversitéClermont Auvergne, F-63000 Clermont-Ferrand, France; ecoudeyre@chu-clermontferrand.fr
5UMRESTTE, IFSTTAR, UniversitéLyon, 42100 Saint Etienne, France; carole.pelissier@chu-st-etienne.fr
6UMRESTTE, IFSTTAR, UniversitéSt Etienne, 42100 Saint Etienne, France
7Inserm, EHESP, Irset (Institut de Recherche en santé, Environnement et Travail), CAPTV-CDC,
UniversitéAngers, CHU Angers, F-49000 Angers, France; alexis.descatha@inserm.fr
8Inserm, EHESP, Irset (Institut de Recherche en santé, Environnement et Travail), CAPTV-CDC,
UniversitéRennes, F-49000 Angers, France
9Department of Family Medicine, Faculty of Medicine, CHU Clermont-Ferrand, ACCePPT,
UniversitéClermont Auvergne, F-63000 Clermont Ferrand, France; thibault.menini@uca.fr
10 Department of Emergency, CNRS, LaPSCo, Physiological and Psychosocial Stress, CHU Clermont-Ferrand,
UniversitéClermont Auvergne, F-63000 Clermont-Ferrand, France
11 Occupational and Environmental Medicine, CNRS, LaPSCo, Physiological and Psychosocial Stress,
CHU Clermont-Ferrand, WittyFit, UniversitéClermont Auvergne, F-63000 Clermont-Ferrand, France;
fdutheil@chu-clermontferrand.fr
*Correspondence: jbb.bouillon@gmail.com; Tel.: +33-6-7436-0423; Fax: +33-4-7327-4649
Abstract:
Background: Exercise therapy is recommended to treat non-specific low back pain (LBP).
Home-based exercises are promising way to mitigate the lack of availability of exercise centers. In
this paper, we conducted a systemic review and meta-analysis on the effects of home-based exercise
on pain and functional limitation in LBP. Method: PubMed, Cochrane, Embase and ScienceDirect
were searched until April 20th, 2021. In order to be selected, studies needed to report the pain and
functional limitation of patients before and after home-based exercise or after exercise both in a center
and at-home. Random-effect meta-analyses and meta-regressions were conducted. Results: We
included 33 studies and 9588 patients. We found that pain intensity decreased in the exclusive home
exercise group (Effect size =
−
0.89. 95% CI
−
0.99 to
−
0.80) and in the group which conducted exercise
both at-home and at another setting (
−
0.73.
−
0.86 to
−
0.59). Similarly, functional limitation also
decreased in both groups (
−
0.75.
−
0.91 to
−
0.60, and
−
0.70,
−
0.92 to
−
0.48, respectively). Relaxation
and postural exercise seemed to be ineffective in decreasing pain intensity, whereas trunk, pelvic or
leg stretching decreased pain intensity. Yoga improved functional limitation. Supervised training was
the most effective method to improve pain intensity. Insufficient data precluded robust conclusions
around the duration and frequency of the sessions and program. Conclusion: Home-based exercise
training improved pain intensity and functional limitation parameters in LBP.
Keywords: musculoskeletal disorders; lumbalgia; physical activity; prevention; public health
1. Introduction
Low back pain (LBP) is a major public health issue [
1
,
2
], commonly described as pain
and discomfort, localized below the costal margin and above the inferior gluteal folds, with
or without leg pain [
3
]. Non-specific LBP is defined as LBP not attributed to a recognizable
Int. J. Environ. Res. Public Health 2021,18, 8430. https://doi.org/10.3390/ijerph18168430 https://www.mdpi.com/journal/ijerph

Int. J. Environ. Res. Public Health 2021,18, 8430 2 of 24
known specific pathology (e.g., inflammatory, tumoral or infectious process) [
3
]. Pain
intensity and functional limitation are major factors in the prognosis of LBP [
4
]. Exercise
therapy is recommended as first-line treatment [
2
,
5
,
6
]. However, the availability of centers
for exercise therapy is lacking in the public health system [
2
,
5
]. Considering that the home
is the most accessible setting [
7
], home-based exercise may be of particular interest in the
management of LBP [
7
]. To facilitate the comparison of results between studies and to
enable the pooling of data in this systematic review, an international multidisciplinary panel
recommended, inter alia, pain intensity and functional limitation as core outcomes [
3
,
8
–
10
].
To our knowledge, to date no meta-analysis has assessed the effects of home-based exercise
on pain intensity and functional limitation in LBP. At exercise centers some meta-analyses
have suggested that a reduction in the risk of LBP could be achieved via various aerobic and
resistance exercise training sessions, pilates and stabilization/motor control [
11
]. However,
a European recommendation highlighted the absence of a clear consensus on the best
exercise therapy [
2
]. For home-based exercise in LBP, data are scarce. Although data
are lacking around the effectiveness of home-based exercise, as well as data regarding
the optimal intensity, frequency and duration of exercise, supervised exercise seemed to
produce the best outcomes in exercise centers [
2
,
5
]. Individual characteristics, such as age,
sex, or education [3], may also influence responses to the home-based exercise program.
In light of this, we conducted a systematic review and a meta-analysis in order to assess
the effect of home-based exercise on the pain intensity and functional limitations in LBP. The
secondary objectives of this study were to assess the influence of the types and modalities
of home-based exercise, and to investigate the putative influence of sociodemographic and
characteristics of patients in the treatment of LBP.
2. Materials and Methods
2.1. Literature Search
We reviewed all studies reporting on the effect of home-based exercise training on
nonspecific LBP (i.e., LBP not consecutive to a specific pathology such as inflammatory,
tumoral or infectious process) [
3
]. Animal studies were excluded. The PubMed, Cochrane
Library, Embase and ScienceDirect databases were searched until 20 April 2021, with the
following keywords: low back pain AND (exercise OR physical) AND home (details of
the specific search strategy used within each database are available in Appendix A). The
search was not limited to specific years and no language restrictions were applied. To
be included, articles were required to simultaneously meet the five following inclusion
criteria: (1) randomized controlled trials (RCTs); (2) population
≥
16 years old; (3) with
non-specific LBP (chronic or not); (4) evaluation of at least one of our main clinically
relevant outcome (i.e., pain intensity or functional limitation); and (5) studies including
home-based exercise therapy. Home exercise programs are defined as a series of exercises
that patients complete at home for therapeutic gains or to improve physical capacity. Home
exercises are designed to be practical, accessible and feasible so that patients can maximize
efforts. We excluded those studies which assessed patients with specific LBP (i.e., caused by
a specific cause such as pregnancy or pathological entities). Conference papers, congress,
and seminars were excluded. In addition, the reference lists of all publications meeting
the inclusion criteria were manually searched in order to identify any further studies not
found through the electronic search. Ancestry searches were also completed on previous
reviews to locate other potentially eligible primary studies. Two authors (ChloéQuentin
and Reza Bagheri) conducted the literature searches, reviewed the abstracts and, based on
the selection criteria, determined the suitability of the articles for inclusion, and extracted
the data. When necessary, disagreements were resolved with the inclusion of a third author
(Frédéric Dutheil).
2.2. Data Extraction
The data collected included: (1) characteristics of the study, including the first author’s
name, publication year, country and continent, study design, outcomes of included arti-

Int. J. Environ. Res. Public Health 2021,18, 8430 3 of 24
cles, and number of participants; (2) characteristics of individuals, such as the mean age,
sex (percentage of males), weight, height, and body mass index, percentage of smokers
and regularly physical active individuals, education and marital status, and duration
of complaints; (3) characteristics of the intervention, such as whether the intervention
was supervised (totally supervised/partially supervised/not supervised), standardized
or individualized (partially or fully), the type of intervention (education, aerobic exercise,
stretching, strengthening, relaxation, postural exercise, yoga, other exercises), the frequency
and duration of sessions, the duration of the program, and the location of training (home or
other setting); and (4) characteristics of our main outcomes, such as the type of assessment
of pain intensity and functional limitation, and measures (mean and standard deviation)
before and after the training.
2.3. Quality of Assessment
We used the Scottish Intercollegiate Guidelines Network (SIGN) criteria designed for
randomized clinical trials to check the quality of included articles. The checklist consists of
10 items. We gave a general quality score for each included study based on main causes of
bias. We used 4 possibilities for scoring each item (yes, no, can’t say or not applicable) [
12
].
2.4. Statistical Considerations
We conducted meta–analyses on the effect of LBP exercise on pain intensity and
functional limitation. P-values less than 0.05 were considered statistically significant. For
the statistical analysis, we used Stata software (version 16, StataCorp, College Station, TX,
USA) [
13
–
15
]. The main characteristics were synthetized for each study population and
reported as a mean
±
standard deviation (SD) for continuous variables and number (%)
of the categorical variables. First, we conducted random-effect meta-analyses (using the
DerSimonian and Laird approach [
16
,
17
]) on the effect of home-based exercise for LBP,
by comparing levels of pain intensity or functional limitation after the training program
versus baseline levels (i.e., before exercise). The results were expressed as effect sizes (ES,
standardized mean differences—SMD). ES is a unitless measure centered at zero if pain
intensity or functional limitation did not differ between after and before the training pro-
gram. A negative ES denoted an improvement in the pain intensity or functional limitation
of the patient (i.e., decreased levels of pain intensity or functional limitation after exercise
compared to before). An ES of
−
0.8 reflects a large effect,
−
0.5 a moderate effect, and
−
0.2 a
small effect. Following this, we conducted meta-analyses stratified on: (1) the location of
the training program (exclusively home, or home plus another setting); (2) characteristics
of intervention, whether it was supervised (totally supervised/partially supervised) or not,
and standardized or individualized (partially or fully). We computed the aforementioned
meta-analysis using all the measurement time. To verify the strength of our results, we
computed sensitivity analyses using only the median time of follow-up and then using only
the last time of follow-up. We evaluated heterogeneity in the study results by examining
forest plots, confidence intervals (CI) and I-squared (I
2
). I
2
values are a common metric
used to measure heterogeneity between studies and are easily interpretable. I
2
values range
from 0 to 100%, and are considered low at <25%, modest at 25–50%, and high at >50% [
18
].
For example, a significant heterogeneity could be linked to the characteristics of the studies,
such as sociodemographic, or the characteristics of the intervention. We searched for poten-
tial publication bias using funnel plots of all the aforementioned meta-analyses, in order to
conduct further sensitivity analyses by excluding studies that were not evenly distributed
around the base of the funnel. When possible (where there was a sufficient sample size),
meta–regressions were proposed in order to study the associations between changes in
pain intensity or functional limitation, and clinically relevant parameters such as sociode-
mographic (age, sex, body mass index, etc.), and the characteristics of the intervention
(e.g., type of exercise, supervised or not, standardized or individualized, frequency and
duration of sessions, and duration of programs). The results were expressed as regression
coefficients and 95% CI.

Int. J. Environ. Res. Public Health 2021,18, 8430 4 of 24
3. Results
An initial search produced 24,699 possible articles. The removal of duplicates and use
of the selection criteria reduced the number of articles reporting the effect of home-based
exercise on LBP patients to 33 articles [
5
,
19
–
49
] (Figure 1). All included articles were written
in English. The main characteristics of the studies are described in Table 1.
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 4 of 23
that were not evenly distributed around the base of the funnel. When possible (where
there was a sufficient sample size), meta–regressions were proposed in order to study the
associations between changes in pain intensity or functional limitation, and clinically rel-
evant parameters such as sociodemographic (age, sex, body mass index, etc.), and the
characteristics of the intervention (e.g., type of exercise, supervised or not, standardized
or individualized, frequency and duration of sessions, and duration of programs). The
results were expressed as regression coefficients and 95% CI.
3. Results
An initial search produced 24,699 possible articles. The removal of duplicates and use
of the selection criteria reduced the number of articles reporting the effect of home-based
exercise on LBP patients to 33 articles [5,19–49] (Figure 1). All included articles were writ-
ten in English. The main characteristics of the studies are described in Table 1.
Figure 1. Flow chart.
Included studies
n=33
Keywords used for search strategy:
“Low back pain” AND “home” AND “exercise”
PubMed
n=251
Cochrane
n=321
Science Direct
n=23690
Embase
n=437
Potential eligible articles
n=24699
Duplicates removed, n=705
Not RCT, n=21156
Not >16 years old, n=157
Not non-specific LBP, n=1942
No pain intensity or functional limitation
outcomes, n=643
Not home-based exercise, n=1063
ScreeningIncluded Eligibility Identification
Home
n=10
Home + other setting
n=23
Figure 1. Flow chart.

Int. J. Environ. Res. Public Health 2021,18, 8430 5 of 24
Table 1. Characteristics of included studies.
Study Characteristics of Indivuals Exercise
Setting Type of Intervention Volume of Exercise Outco Mes
Study Design Coun-
try n gp
Age
(Mean ±
SD)
Sex
(%
Men)
Home Other Stren-
gth
Stret-
ching
Rela-
xation
Aero-
bic
Edu-
cation
Postu-
ral Yoga Other Number
of weeks
n Session/
Week
Duration
of
Session
Pain Functionnal
Disability
Alp 2014 RCT Turkey
24 48 ±27.5 0 X X X
6 weeks
3 45–60 min
VAS RMDQ
24 51 ±39.8 0 X X X 7 ?
Ben Salah
Frih 2009 RCT Tuni-
sia
54 34.7 ±1.14 24.1 X X X X 4 weeks 7 30 min
VAS
53 36.9 ±1.29 26.4 X X X Proprioception
exercise 4 weeks 3 90 min
Bernadelli
2020
RCT Italy 51 50.5 ±9.7 25.5 X X X X 7 weeks 130 min RMDQ
50 51.9 ±8.1 16 X X X
Bertozzi
2015
RCT Italy 20 42.7 ±8.7 - X X X X X 5 weeks 2 60 min VAS RMDQ
20 47.5 ±7.5 - X X X X ? ?
Bronfort
2014
RCT USA 96 57.1 ±12 41 X X X X X 12 weeks 7 ? NPRS RMDQ
96 57.7 ±11.9 32 X X X X
Bronfort
2011
RCT USA 100 44.5 ±11.8 43 X X X 12 weeks 2 60 min
100 45.2 ±10.8 44
Spinal
manipulative
therapy
12 weeks 2 60 min NPRS RMDQ
101 45.6 ±10.3 41.6 X X X X 12 weeks 7 60 min
Buttagat
2019
RCT Thai-
land 11 39.7 ±17.4 27.2 X X Thai
self-massage 4 weeks 3 ? VAS ODI
11 41.3 ±15.8 9 X X ? ? ?
Chaléat-
Valayer
2016
RCT France 171 47.1 ±8.5 23 X X X X X X rhythmic
exercise 2 years 7 10 min VAS QBPDS
Descarreaux
2002
RCT Ca-
nada 10 33.1 70 X X 3 weeks 14 ? VAS ODI
20 35.0 35 X X X 6 weeks 14 ?
Ewert
2009
RCT Ger-
many 100 37.9 ±11.6 8.0 X X X X X X X X
cognitive–
behavioral ap-
proach/stress
control +
warm up
13 weeks 2 60 min WHYMPI sf36-pcs
102 41.1 ±10.8 5.9 X X X X X X Warm up 13 weeks ? ?

Int. J. Environ. Res. Public Health 2021,18, 8430 6 of 24
Table 1. Cont.
Study Characteristics of Indivuals Exercise
Setting Type of Intervention Volume of Exercise Outco Mes
Study Design Coun-
try n gp
Age
(Mean ±
SD)
Sex
(%
Men)
Home Other Stren-
gth
Stret-
ching
Rela-
xation
Aero-
bic
Edu-
cation
Postu-
ral Yoga Other Number
of weeks
n Session/
Week
Duration
of
Session
Pain Functionnal
Disability
Frost 1998
RCT En-
gland 36 34.2 ±9.4 - X X X X X X X
4 weeks
2 ?
MODI
35 38.5 ±9.3 - X X X X ? ?
Garcia
2013
RCT Brasil 74 54.2 ±1.57 31.0 X X X X X 24 weeks 7240 min VAS RMDQ
74 53.7 ±1.53 21.6 X X X X X
Goode
2018
RCT En-
gland 20 69.6 ±3.5 95 X X X X X X
20 69.5 ±4,0 90 X X X X X X
Activity
pacing +
Cognitive
restructuring
12 weeks ? ? RMDQ
20 71.9 ±6.5 95 X X
Groessl
2017
RCT USA 76 53.3 ±12.7 73 X X X Breathing 12 weeks 7 60 min BPI RMDQ
76 53.6 ±13.9 75 none - -
Haufe
2017
RCT Ger-
many 112 43.5 ±9.7 - X X X 20 weeks 3 20 min
114 41.9 ±10.6 - 20 weeks 3 20 min VAS ODI
10 49.9 ±8.8 80 X X X X X X 6 weeks 2 20 min
Ibrahim
2018
RCT Nige-
ria 10 48.5 ±14.9 70 X X X X X X 6 weeks 2 20 min NPRS ODI
10 50.3 ±9.1 90 X X X X X 1 ?
Iversen
2018
RCT Nor-
way 37 43 ±13 46 X X X X X X 12 weeks 4 ?
37 47 ±11 41 X X X X X X
ball games +
body
awareness +
circle training
12 weeks 4.5 ? NPRS ODI
34 45 ±15 55 none - -
Kanas
2018
RCT Brasil 17 - - X X X X 8 weeks 3?NPRS RMDQ
13 - - X X X X X
Kendall
2015
RCT Ca-
nada 40 33 55 X X X X RTUS
6 weeks ? ?
VAS ODI
Aus-
tralia 40 41 40 X X X X RTUS

Int. J. Environ. Res. Public Health 2021,18, 8430 7 of 24
Table 1. Cont.
Study Characteristics of Indivuals Exercise
Setting Type of Intervention Volume of Exercise Outco Mes
Study Design Coun-
try n gp
Age
(Mean ±
SD)
Sex
(%
Men)
Home Other Stren-
gth
Stret-
ching
Rela-
xation
Aero-
bic
Edu-
cation
Postu-
ral Yoga Other Number
of weeks
n Session/
Week
Duration
of
Session
Pain Functionnal
Disability
Kolda¸s
2008
RCT Turkey 20 37.1 ±6.5 21.1 X X X X X X 10 ?
20 41.5 ±8.3 22.2 X X X X X 6 weeks 7 ? VAS RMDQ
20 42.1 ±9.5 22.2 X X X X 7 ?
Kuukkanen
2000
RCT Fin-
land 29 39.9 ±8.9 - X X warm-up +
Balance +
coordination
12 weeks ? ?
29 39.9 ±7.9 - X X 12 weeks ? ? ODI
28 39.9 ±7.9 - none - -
Kuukkanen
2007 RCT Fin-
land 28 40 ±7.9 46.4 X X X 12 weeks 7 ?
Borg
CR-10
scale
ODI
Miller
2007
RCT En-
gland 98 44.1 ±16.2 - X 5 weeks ? ?
137 43.7 ±14.8 - X 5 weeks ? ? RMDQ
150 44.9 ±15.4 - - - -
Michalsen
2016
RCT Ger-
many 32 55.5 ±10.6 - X X Jyoti
meditaion 8 weeks 7
25 min
VAS RMDQ
Ger-
many 36 54.8 ±10.6 - X X X 20 min
Neyaz
2019
RCT India 35 33 - X X X X X X 6 weeks 730–35 min DVPRS RMDQ
35 38 - X X X X
Shirado
2010
RCT Japan 103 42.0 ±11.6 47.5 X X X X 8 weeks 14 ?VAS
98 42.5 ±12.3 40.8 X Massage ?
Schulz
2019
RCT USA 81 72.5 ±5.6 43.2 X X X X X X
Balance
exercise +
massage
2 45–60 min
80 73.6 ±5.3 52.5 X X X X X X
Balance
exercise +
massage
12 weeks 1 60 min NPRS RMDQ
80 74.7 ±5.6 50.0 X X X X X 1 15 min
Saper
2017
RCT USA 127 46.4 ±10.4 - X X X X breathing ? 75 min
129 46.4 ±11,0 - X X X X 12 weeks 7 60 min NPRS RMDQ
64 44.2 ±10.8 - X ? ?

Int. J. Environ. Res. Public Health 2021,18, 8430 8 of 24
Table 1. Cont.
Study Characteristics of Indivuals Exercise
Setting Type of Intervention Volume of Exercise Outco Mes
Study Design Coun-
try n gp
Age
(Mean ±
SD)
Sex
(%
Men)
Home Other Stren-
gth
Stret-
ching
Rela-
xation
Aero-
bic
Edu-
cation
Postu-
ral Yoga Other Number
of weeks
n Session/
Week
Duration
of
Session
Pain Functionnal
Disability
Sakuma
2012
RCT Japan 67 32.6 ±11.5 - X X X 2 weeks 7 9 min
VAS
31 35.8 ±13 none - -
Tottoli
2019
RCT Brazil 72 -X X X X 6 weeks 250 min VAS BQBPSDQ
72 X X X X Warm up
Wajswelner
2012
RCT Aus-
tralia 44 49.3 ±14.1 X X X Breathing 24 weeks 60 min NPRS
43 48.9 ±16.4 X X X X Swiss ball
Winter
2015
RCT Aus-
tralia 12 45.9 ±13.3 X X 5
13 48.9 ±7.2 X X 6 weeks 5 NPRS MODI
13 38.3 ±12.8 X X X 3
Zadro
2019
RCT Aus-
tralia 30 68.8 ±5.5 40.0 X X X X 8 weeks 3 60 min NPRS RMDQ
30 67.8 ±6 56.6 none

Int. J. Environ. Res. Public Health 2021,18, 8430 9 of 24
3.1. Quality of Assessment
Overall, the methodological quality of the included studies was good, with an average
score of 75% for items meeting the criteria of the SIGN checklist, ranging from 40% [
5
,
44
] to
from 90% [
32
,
42
,
50
]. All studies failed to include a blind assessment. All studies reported
achieving ethical approval (Figure 2).
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 8 of 23
3.1. Quality of Assessment
Overall, the methodological quality of the included studies was good, with an aver-
age score of 75% for items meeting the criteria of the SIGN checklist, ranging from 40%
[5,44] to from 90% [32,42,50]. All studies failed to include a blind assessment. All studies
reported achieving ethical approval (Figure 2).
Figure 2. Summary of methodological qualities of included studies using the SIGN checklist.
3.2. Study Designs of Included Articles
The included studies were published between 1998 [28] and 2020 [51] and conducted in
various geographic locations, with all continents represented (Europe [19,25,27,28,30,32,34,36–
39,48,51], North America [22,26,31,35,42,50], South America [5,29,44], Asia [23,24,40,41,43], Af-
rica [20], and Oceania [35,45,46,49]. All the studies were RCT. Thirteen studies were monocen-
tric [5,19–24,29–31,33,42] and eleven were multicentric [25,27,32,35,37,38,40,41,43,50,51]. Stud-
ies were single-blind [19,23–25,28–30,32,33,35] or not blind randomized trials [5,22,27,47,51].
3.3. Inclusion and Exclusion Criteria of Included Studies
All the included studies included adults, except one study that also included partic-
ipants over 16 years old [39]. Globally, participants were recruited using electronic, news-
paper or local advertisements [23,25,26,33,35,42,44–47,49,50] or from consultations with
specialists or general practitioners [5,19,20,25,40,41,49]. Some studies included specific
populations, such as healthcare workers [25,27,51], sedentary older adults [30,42], poultry
industry slaughterers [21], only women [19], or individuals from a rural community [33].
3.4. Population
The sample sizes of the studies ranged from 22 [23] to 385 participants [39]. We in-
cluded a total of 9,588 LBP patients. The ages of the participants were reported in all except
two of the studies [5,44]. The mean age of LBP patients undertaking home-based exercise
training was 49.3 years (95% CI 45.5 to 52.9), with ages ranging from 32.6 ± 11.5 [43] to 74.7
± 6.0 [42] years old. Gender was not reported in 14 of the selected studies
[5,21,22,24,34,38,40,43,44,46,47,50]. The mean proportion of men was 18% (95% CI 0.15 to
0.20), with the proportion of men in the studies ranging from 0 [19] to 53% [42]. The BMI
of participants was reported in 16 of the selected studies. The mean BMI was 29.5 kg/m²
(95% CI 28.3 to 26.9), with BMIs ranging from 21.5 ± 2.7 [33] to 32.7 ± 7.4 [50]. Other pa-
rameters were seldomly reported. The education status of participants was reported in
eight studies [27,29,31,33,34,42,49], but degrees were not expressed in the same way across
most of the studies. Smoking status was only reported in six studies [25,28,29,42,43,49],
with a mean proportion of smokers of 4% (95%CI 2 to 5%), ranging from 0% [47] to 11%
0% 20% 40% 60% 80% 100%
Appropriate and clearly focused question
Allocation concealment (selection bias)
Adequate concealment method is used*
Subjects and investigators blind about treatment*
Treatment and control groups are similar
Outcomes are measured in a standard and valid way
Number of dropped outs (%)
Analyses in randomly allocated groups
Results are comparable for all sites
General level of evidence
Risk of bias summary
Cohort Studies
Low risk of bias Unclear risk of bias High risk of bias
Figure 2. Summary of methodological qualities of included studies using the SIGN checklist.
3.2. Study Designs of Included Articles
The included studies were published between 1998 [
28
] and 2020 [
51
] and conducted
in various geographic locations, with all continents represented (Europe [
19
,
25
,
27
,
28
,
30
,
32
,
34
,
36
–
39
,
48
,
51
], North America [
22
,
26
,
31
,
35
,
42
,
50
], South America [
5
,
29
,
44
], Asia [
23
,
24
,
40
,
41
,
43
], Africa [
20
], and Oceania [
35
,
45
,
46
,
49
]. All the studies were RCT. Thirteen studies
were monocentric [
5
,
19
–
24
,
29
–
31
,
33
,
42
] and eleven were multicentric [
25
,
27
,
32
,
35
,
37
,
38
,
40
,
41
,
43
,
50
,
51
]. Studies were single-blind [
19
,
23
–
25
,
28
–
30
,
32
,
33
,
35
] or not blind randomized
trials [5,22,27,47,51].
3.3. Inclusion and Exclusion Criteria of Included Studies
All the included studies included adults, except one study that also included par-
ticipants over 16 years old [
39
]. Globally, participants were recruited using electronic,
newspaper or local advertisements [
23
,
25
,
26
,
33
,
35
,
42
,
44
–
47
,
49
,
50
] or from consultations
with specialists or general practitioners [
5
,
19
,
20
,
25
,
40
,
41
,
49
]. Some studies included specific
populations, such as healthcare workers [
25
,
27
,
51
], sedentary older adults [
30
,
42
], poultry
industry slaughterers [21], only women [19], or individuals from a rural community [33].
3.4. Population
The sample sizes of the studies ranged from 22 [
23
] to 385 participants [
39
]. We
included a total of 9,588 LBP patients. The ages of the participants were reported in
all except two of the studies [
5
,
44
]. The mean age of LBP patients undertaking home-
based exercise training was 49.3 years (95% CI 45.5 to 52.9), with ages ranging from
32.6 ±11.5 [43]
to 74.7
±
6.0 [
42
] years old. Gender was not reported in 14 of the se-
lected studies [
5
,
21
,
22
,
24
,
34
,
38
,
40
,
43
,
44
,
46
,
47
,
50
]. The mean proportion of men was 18%
(95% CI 0.15 to 0.20), with the proportion of men in the studies ranging from 0 [
19
] to
53% [
42
]. The BMI of participants was reported in 16 of the selected studies. The mean
BMI was 29.5 kg/m
2
(95% CI 28.3 to 26.9), with BMIs ranging from 21.5
±
2.7 [
33
] to
32.7 ±7.4 [50]
. Other parameters were seldomly reported. The education status of partici-
pants was reported in eight studies [
27
,
29
,
31
,
33
,
34
,
42
,
49
], but degrees were not expressed
in the same way across most of the studies. Smoking status was only reported in six
studies [25,28,29,42,43,49]
, with a mean proportion of smokers of 4% (95% CI 2 to 5%),
ranging from 0% [
47
] to 11% [
29
]. Only three studies mentioned leisure physical activ-

Int. J. Environ. Res. Public Health 2021,18, 8430 10 of 24
ity [
20
,
29
,
43
], with a mean proportion of regularly active patients of 10% (95% CI 6 to 15%),
and proportions varying from 3 [43] to 18% [29].
3.5. Intervention: Characteristics of Exercise
3.5.1. Type of Exercise
Nearly all of the selected studies (26 studies i.e., 79%) used strength-based exer-
cises, mostly combined with other exercise [
5
,
19
,
20
,
22
–
25
,
27
,
29
,
30
,
33
–
38
,
40
–
42
,
44
–
46
,
48
,
51
].
Only two of the studies did not [
26
,
32
]. Education was included in sixteen of the stud-
ies [
22
,
23
,
25
,
27
–
30
,
32
–
36
,
40
–
42
,
47
,
50
,
51
], stretching in twenty-three studies [
5
,
19
–
21
,
23
–
37
,
40
–
42
,
44
–
49
,
51
], aerobic exercise in thirteen studies [
5
,
22
,
24
,
27
,
28
,
30
,
32
–
36
,
42
,
49
,
50
],
postural exercise in eight studies [
21
,
25
,
27
–
29
,
44
,
45
,
47
], relaxation in eight studies [
21
,
27
,
28
,
30
,
34
,
40
,
43
,
50
], and yoga in four studies [
26
,
29
,
30
,
52
]. Other exercises were only oc-
casionally reported, including Thai self-massage [
23
], spinal manipulative therapy [
22
],
stress-controlling techniques and a behavioral approach [
27
], Jyoti meditation [
48
], breath-
ing [31,50], and ball games associated with body awareness and circle training [34].
3.5.2. Duration of Intervention
The duration of the invention was reported in all of the selected studies, with the
programs lasting an average of 11.4 weeks, and varying from 2 weeks [43] to 2 years [25].
3.5.3. Frequency and Duration of Sessions
On average, the studies reported 4.8 sessions per week—ranging from 1 [42,51] to 14 [26]
sessions per week—with each session lasting 63 min—ranging from 9 [
43
] to 240 min [
29
].
The frequency of sessions was not reported in four of selected studies [
30
,
35
,
39
,
45
], and the
duration of sessions was not reported in in thirteen studies [5,23,28,30,34–39,41,46,47].
3.5.4. Standardization
Standardization was not reported in seven of the selected studies [
23
,
30
,
35
,
39
,
41
,
47
,
51
].
The exercises were standardized in twenty of the studies [
5
,
19
,
21
,
25
,
28
,
29
,
31
–
37
,
40
,
43
,
45
,
46
,
48
–
50
], partially standardized in six of the studies [
27
,
29
,
38
,
42
,
44
,
47
], and individualized
in five of the studies [20,24,26,27,45].
3.5.5. Supervision
Supervision was reported in all except two of the studies [
23
,
34
]. Exercises were fully
supervised in eight studies [
19
,
20
,
33
,
39
,
44
,
45
,
47
,
51
], partially supervised in twenty-one
studies [
5
,
20
,
21
,
25
,
27
–
34
,
36
,
37
,
40
–
42
,
44
,
47
,
48
,
50
], and not supervised in ten studies [
19
,
28
,
35,36,42,43,46,48,49,51].
3.5.6. Location
The location was reported in all of the studies. Exercises took place exclusively at
home in twenty-one studies [
5
,
19
,
21
–
23
,
26
,
28
,
30
,
35
–
38
,
41
–
44
,
46
–
49
,
51
] and both at home
and another setting (workplace, health center or training center) in eighteen studies [
5
,
20
,
21,25,27–29,31–34,36,40,42,45,47,48,50].
3.6. Outcomes-Pain Intensity and Functional Limitations
Before and after the physical exercise program, the pain intensity was assessed
in 27 studies [
5
,
19
–
27
,
29
,
31
–
37
,
40
–
50
] and functional limitations in 28 studies [
5
,
19
,
21
–
35
,
37
–
40
,
42
,
44
,
46
–
51
]. Participants’ pain intensity was evaluated in most studies using
a visual analogue scale [
19
–
21
,
23
,
25
,
26
,
29
,
32
,
35
,
36
,
41
,
43
,
44
,
48
], or a numeric pain rating
scale [5,22,24,33,34,42,45–47,49,50]
. Other pain assessments were made using the West
Haven-Yale Multidimensional Pain Inventory [
27
], the Brief Pain Inventory [
31
], the Borg
CR-10 scale [
37
], and the Defense and Veterans Pain Rating Scale [
40
]. Functional disability
was evaluated in most of the studies using the Roland-Morris Disability [
5
,
19
,
21
,
22
,
29
–
31
,
36
,
39
,
40
,
42
,
47
–
51
], the Oswestry Disability Index [
23
,
32
–
35
,
37
,
38
] or its modified ver-

Int. J. Environ. Res. Public Health 2021,18, 8430 11 of 24
sion [
24
,
28
,
46
], except in three studies that used the French version of the Quebec back pain
disability scale [
25
], the Short Form Health Survey physical component scale [
27
], and the
Quebec Back Pain Disability Scale Questionnaire [
44
]. Assessments of the outcomes were
made at a median time of three months after the beginning of the exercise program, ranging
from half a month [
43
] to five years [
37
]. Some studies reported outcomes at different times
during the exercise protocol [5,21,22,25,27–29,31,36,37,40,42,43,45,47,48,51].
3.7. Meta-Analysis on the Effect of Home-Based Exercise
Overall, home-based exercise training decreased pain intensity (effect size =
−
0.89,
95% CI
−
0.99 to
−
0.80) and decreased functional limitation (
−
0.73%,
−
0.86 to
−
0.59) for
participants, regardless of an exclusive at-home location or not. Pain intensity decreased
in a similar proportion between an exclusive at-home setting (
−
0.97,
−
1.14 to
−
0.79) and
a combination of exercises at home and in another setting (
−
0.89,
−
0.96 to
−
0.74). Similarly,
functional limitation also improved in both settings (
−
0.69,
−
0.93 to
−
0.46; and
−
0.93,
−1.34 to −0.52, respectively) (Figures 3and 4, and Appendix B).
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 10 of 23
scale [37], and the Defense and Veterans Pain Rating Scale [40]. Functional disability was
evaluated in most of the studies using the Roland-Morris Disability [5,19,21,22,29–
31,36,39,40,42,47–51], the Oswestry Disability Index [23,32–35,37,38] or its modified version
[24,28,46], except in three studies that used the French version of the Quebec back pain disa-
bility scale [25], the Short Form Health Survey physical component scale [27], and the Quebec
Back Pain Disability Scale Questionnaire [44]. Assessments of the outcomes were made at a
median time of three months after the beginning of the exercise program, ranging from half a
month [43] to five years [37]. Some studies reported outcomes at different times during the
exercise protocol [5,21,22,25,27–29,31,36,37,40,42,43,45,47,48,51].
3.7. Meta-Analysis on the Effect of Home-Based Exercise
Overall, home-based exercise training decreased pain intensity (effect size= −0.89,
95% CI −0.99 to −0.80) and decreased functional limitation (−0.73%, −0.86 to −0.59) for par-
ticipants, regardless of an exclusive at-home location or not. Pain intensity decreased in a
similar proportion between an exclusive at-home setting (−0.97, −1.14 to −0.79) and a com-
bination of exercises at home and in another setting (−0.89, −0.96 to −0.74). Similarly, func-
tional limitation also improved in both settings (−0.69, −0.93 to −0.46; and −0.93, −1.34 to
−0.52, respectively) (Figures 3 and 4, and Appendix B).
Figure 3．Summary of meta-analysis on the effect of home-based exercise on pain intensity and
functional limitation, stratified by setting (exclusive home-based training versus home-based and
other setting), supervision, and standardization of training.
n studies I-squared Weight
(subgroups) (%) (%)
Pain
By location of training
Home 13 (31) 91.4 -0.97 (-1.14 t o -0.79) 37.2
Health cent er + h ome 14 (50) 90.2 -0.85 (-0.96 to -0.74) 62.8
By supervision o f exercise
Totally sup ervised 4 (8) 84.9 -1.19 (-1.31 t o -1.06) 24.3
Partial ly su pervised 14 (20) 88.3 -0.71 (-0.82 t o -0.60) 48.9
Not su pervised 8 (14) 88. 8 -0.93 (-1.10 to -0.77) 26.8
By personnalisation of exercise
Individu alised 4 (4) 94.9 -1.00 ( -1.42 to -0.57) 10.1
Partial ly in dividu alised 4 (7) 89. 5 -0.67 (-0.80 to -0. 54) 30.4
Stand ardized 17 (29) 88.4 -0.95 (-1.08 to -0.83) 59.5
Overall 27 (81) 90.2 -0.89 (-0.99 to -0.80) 100
Functional limitation
By location of training
Home 12 (17) 89.3 -0.75 (-0.91 t o -0.60) 44.7
Health cent er + h ome 10 (19) 97.8 -0.70 (-0.92 to -0.48) 55.3
By supervision o f exercise
Totally sup ervised 5 (9) 85.3 -0.76 (-0.88 t o -0.65) 22.9
Partial ly su pervised 13 (42) 97.2 -0.76 (-1.00 t o -0.52) 49.0
Not su pervised 8 (24) 77. 1 -0.60 (-0.71 to -0.48) 28.1
By personnalisation of exercise
Individu alised 2 (4) 97.8 -0.32 ( -1.06 to 0.43) 6.0
Partial ly in dividu alised 4 (22) 95. 2 -0.45 (-0.64 to -0. 26) 33.3
Stand ardized 14 (43) 94.2 -0.96 (-1.16 to -0.76) 60.7
Overall
22 (36)
90.2
-0.73 (-0.86 t o -0.59) 100
Effect size
(95% CI)
-1.5 -1 -0.5 0 0.5
Figure 3.
Summary of meta-analysis on the effect of home-based exercise on pain intensity and
functional limitation, stratified by setting (exclusive home-based training versus home-based and
other setting), supervision, and standardization of training.

Int. J. Environ. Res. Public Health 2021,18, 8430 12 of 24
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 11 of 23
Figure 4. Meta-analysis on the effect of home-based exercise on pain intensity, stratified by setting
(exclusive home-based training versus home-based and other setting).
Figure 4.
Meta-analysis on the effect of home-based exercise on pain intensity, stratified by setting
(exclusive home-based training versus home-based and other setting).

Int. J. Environ. Res. Public Health 2021,18, 8430 13 of 24
3.8. Stratification by Characteristics of Training
Stratification by the supervision of training demonstrated a decrease in pain intensity
and an improvement of functional limitation regardless of the characteristics of the training.
For pain intensity, a totally supervised training seemed to be the most effective in terms
of decreasing the pain intensity (effect size =
−
1.19, 95% CI
−
1.31 to
−
1.06; versus
−
0.71,
−
0.82 to
−
1.06 for partially supervised training and
−
0.93;
−
1.1 to
−
0.77 for unsupervised
training). For functional limitation, improvement seemed similar regardless of the level of
supervision of training (
−
0.76,
−
0.88 to
−
0.65 for totally supervised training;
−
0.76;
−
1.0
to
−
0.52 for partially supervised training, and
−
0.60,
−
0.71 to
−
0.48 for unsupervised
training). Concerning the standardization of training, both for pain intensity and functional
limitation, a standardized protocol seemed to produce the greatest benefits (
−
0.95,
−
1.31
to
−
1.08 for pain intensity, and
−
0.96,
−
1.16 to
−
0.76 for functional limitation), whereas
a partially individualized program had the lowest benefits (
−
0.67,
−
0.8 to
−
0.54 for pain
intensity and
−
0.45,
−
0.64 to
−
0.26 for functional limitation). An individualized program
demonstrated very wide confidence intervals for pain intensity (
−
1.00,
−
1.42 to
−
0.57)
and was not significant for functional limitation (−0.32; −1.06 to 0.43) (Figure 4).
3.9. Metaregressions
There was no difference in the improvement of pain intensity and functional limita-
tion depending on the setting (exclusive home-based exercise vs. home-based exercise
combined with exercises in a center, p= 0.66). Totally supervised exercise produced better
benefits regarding pain intensity when compared with partially individualized (coefficient
−
0.50, 95% CI
−
0.74 to
−
0.25) or not supervised (
−
0.28,
−
0.58 to
−
0.01) programs, with no
influence on functional limitation. Standardized protocols had better benefits when com-
pared to partially individualized training in relation to both pain intensity (
−
0.29,
−
0.55
to
−
0.03) and functional limitation (
−
0.51,
−
0.84 to
−
0.18). Despite most studies mixing
different types of exercise, metaregressions demonstrated an improvement in pain intensity
for pelvic (
−
0.63,
−
0.92 to
−
0.30), leg (
−
0.27,
−
0.52 to
−
0.02) and trunk (
−
0.36,
−
0.65 to
−
0.07) stretching. In contrast, pain intensity seemed to be exacerbated by relaxation (0.38,
0.12 to 0.65). Postural exercises seemed to have a deleterious effect on both pain intensity
(0.35, 0.11 to 0.59) and functional limitation (0.24, 0.00 to 0.68). Yoga improved functional
limitation (
−
0.94,
−
1.67 to
−
0.2). The volume of training (the frequency and duration
of sessions, and duration of programs) was not associated with an improvement in pain
intensity or functional limitation. A longer follow-up was associated with a decrease in
pain intensity (effect size =
−
0.03. 95% CI
−
0.05 to
−
0.01) and functional limitation (
−
0.06;
−
0.10 to
−
0.02). Men were more likely to improve pain intensity (
−
0.16,
−
0.23 to
−
0.08,
per 10% men) and functional limitation (
−
0.23,
−
0.30 to
−
0.16, per 10%men) to a greater
extent than women. The training program was less effective for decreasing pain intensity
in people with a higher body mass (1.01, 0.19 to 1.85, per 10 kg
·
m
2
). Other parameters,
such as age, education status, smoking, or duration of symptoms, were not associated with
decreased pain intensity and functional limitation (Figure 5).

Int. J. Environ. Res. Public Health 2021,18, 8430 14 of 24
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 13 of 23
Figure 5. Metaregressions i.e., putative influencing variables on pain intensity and functional limitation following home-
based exercise in LBP.
3.10. Sensitivity Analyses
We computed sensitivity analyses using only the median time of follow-up (i.e., three
months (Appendix C for meta-analysis and Appendix D for metaregressions)), and the
last time of follow-up (Appendices E and F). All the results were similar. Because of the
wide heterogeneity of the selected studies (all I-squared are >80%), we failed to reperform
all the aforementioned meta–analyses after the exclusion of studies that were not evenly
distributed around the base of the funnel (Appendix G).
4. Discussion
The main findings of this research were that home-based exercise training improved
pain intensity and functional limitation in LBP patients, regardless the modality of exer-
cises. Supervised training and standardized training improved pain intensity to the great-
est extent, independently of the influence of the duration and frequency of the training.
Training was less beneficial for women and for patients with a high body mass index.
4.1. The Benefits of Home Exercise Training on LBP Patients
This study is the first systematic review and meta-analysis of studies investigating
the effectiveness of home exercise programs on pain and functional limitation in patients
with LBP. Structured center-based programs have the advantage that the amount and
quality of the training can be controlled and supervised, but these programs are expen-
sive, limiting their implementation possibilities [7]. Moreover, many adults experience
Pain intensity
p-value
Functional limitation
p-value
(%) (%)
Sociodemographic
Age, per 10-year 0.05 (- 0.05 to 0.15) 0.29 0.05 (-0.10 to 0.20) 0.46
Sex, per 10% male -0.16 (-0.23 to - 0.08)
<0.001
-0.23 (-0.30 to -0. 16)
<0.001
Body mass index, per 10 km/ m2 1.01 (0.19 to 1.85)
0.018
-0.03 (-1.3083 to 0.76
)
0.59
Smoking, per 10% smokers -0.08 (-0. 40 to 0.30) 0.64 -0.22 (-0.40 to -0. 01)
0.037
Phyisicall y active, p er 10% p eople -0.10 (-0.40 t o 0.20) 0.38 0.42 (0.10 to 0.70)
0.015
Married, per 10% 0.03 (-0.04 to 0. 11) 0.32 0.02 (-0.07 to 0.10) 0.68
Duration of symp tom, 10-years 0.20 (-0.26 to 0. 62) 0.41 -0.08 (-0.50 to 0.40) 0.73
Parameters of exercise
n weeks t raining , per 10-week 0.09 (-0.01 to 0.18) 0.08 0.12 (-0.10 to 0.40) 0.44
n weeks post-trainin g, per 10-week -0.03 (-0.05 to - 0.01)
0.028
-0.06 (-0.10 to -0. 02)
0.006
n min par sess ion, p er 10-min 0.00 (-0.01 to 0.03) 0.27 0.01 (-0.02 to 0.03) 0.71
n set per session , pe r 10-session 0.10 (-0.10 to 0.30) 0.34 0.00 (-0.10 to 0.20) 0.97
n session by weeks, per 10-session 0. 28 (-0.10 to 0.70) 0.19 -0.26 (-0.80 to 0.30) 0.38
Type of exercise, yes vs n o
Educatio n 0.04 (-0.20 to 0.29) 0.73 0.28 (-0.03 to 0.58) 0.08
Aerobic -0.01 (-0.25 to 0. 24) 0.94 0.17 (-0.13 to 0.47) 0.27
Streng ht 0.13 (-0. 14 to 0.41) 0.34 0.24 (-0.09 to 0.56) 0.16
Stretching -0.07 (-0.35 to 0. 21) 0.60 0.09 (-0.27 to 0.45) 0.62
Relaxation 0.38 (0.12 to 0.65)
0.007
0.24 (-0.14 to 0.61) 0.21
Postural exercise 0.35 (0.11 to 0. 59)
0.006
0.34 (-0.00 to 0.68)
0.050
Yoga 0.35 (-0.11 to 0.81) 0.13 -0.94 (-1.67 to -0. 20)
0.013
Details of strengthening, yes vs no
pelvic mu scle s trengt henin g 0.09 (-0. 13 to 0.31) 0.43 0.21 (-0.09 to 0. 51) 0.17
legs s treng thenin g 0.04 (-0.22 to 0.3) 0.77 -0.21 (-0.63 to 0.21) 0.33
abdomin al stren gth ening -0.09 (-0.31 to 0.13) 0.41 -0.05 (-0. 35 to 0.24) 0 .72
Details of stretching, yes vs no
Trunk s trechin g -0.36 (-0.66 to -0.07)
0.015
-0.41 (-0.85 to 0.02) 0.063
Abdominal stretch ing 0.02 (-0.75 to 0.8) 0.95 -0.30 (-1.27 to 0.67) 0.54
Pelvic stretching -0.63 (-0.92 to -0.34)
<0.001
-0.45 (-0.94 to -0. 05) 0.076
Leg stretching -0.27 (-0.52 to -0.02)
0.031
-0.03 (-0.43 to 0.36) 0.87
Standardized / individualised
Totally in d. vs stand ardised -0.02 (-0.43 to 0.40) 0.94 0.65 (- 0.01 to 1.31) 0.054
Totally in d. vs partiall y ind . -0.30 (-0.74 to 0.14) 0. 17 0.14 (-0. 55 to 0.82) 0.69
Standardized vs partially ind . -0.29 (-0.55 to -0.03)
0.03
-0.51 (-0.84 to -0. 18)
0.003
Supervised exercises
Totally vs partiall y sup ervised -0.50 (-0.74 to -0.25)
<0.001
-0.03 (-0.36 to 0.31) 0.86
Totally vs not su pervised -0.28 (-0.56 to - 0.01)
0.046
-0.19 (-0.57 to 0.18) 0.32
Partially vs not supervised 0.22 (-0.02 to 0.5) 0.067 -0.16 (-0.47 to 0.15) 0.31
Location of training
Home + o
t
he
r
se
t
t
in
g
vs home 0.10
(
-0.1
5
t
o 0.3
5
)
0.66 0.07
(
-0.
2
3
t
o 0.37
)
0.66
Coefficient
(95% CI)
Coefficien t
(95% CI)
Figure 5.
Metaregressions i.e., putative influencing variables on pain intensity and functional limitation following home-
based exercise in LBP.
3.10. Sensitivity Analyses
We computed sensitivity analyses using only the median time of follow-up (i.e., three
months (Appendix Cfor meta-analysis and Appendix Dfor metaregressions)), and the
last time of follow-up (Appendices Eand F). All the results were similar. Because of the
wide heterogeneity of the selected studies (all I-squared are >80%), we failed to reperform
all the aforementioned meta–analyses after the exclusion of studies that were not evenly
distributed around the base of the funnel (Appendix G).
4. Discussion
The main findings of this research were that home-based exercise training improved
pain intensity and functional limitation in LBP patients, regardless the modality of exercises.
Supervised training and standardized training improved pain intensity to the greatest
extent, independently of the influence of the duration and frequency of the training.
Training was less beneficial for women and for patients with a high body mass index.
4.1. The Benefits of Home Exercise Training on LBP Patients
This study is the first systematic review and meta-analysis of studies investigating
the effectiveness of home exercise programs on pain and functional limitation in patients
with LBP. Structured center-based programs have the advantage that the amount and
quality of the training can be controlled and supervised, but these programs are expensive,
limiting their implementation possibilities [
7
]. Moreover, many adults experience barriers
to attending such programs, including a lack of affinity with the culture of fitness centers [
7
].

Int. J. Environ. Res. Public Health 2021,18, 8430 15 of 24
Home-based exercises are especially valuable because they require fewer resources [
52
]
and less time from health institutions and health practitioners [
7
]. Our meta-analysis
showed strong evidence that physical exercise training can take place at home to improve
LBP, even though we found no studies comparing the same training program between
home and another setting. Studies comparing home-based exercise to a control group
without exercise [
25
,
31
,
38
,
43
] showed an improvement in pain intensity and functional
limitation. Thus, home-based exercise training could be a cost-effective intervention in the
treatment of LBP. If multiple short bouts of moderate-intensity physical exercise produce
significant training effects [
53
], learning to integrate physical activity into daily life can
become a main goal in the treatment of LBP. Moreover, home-based exercise also improves
other comorbidities, such as knee osteoarthritis [
54
], obesity [
55
], depression [
56
], gait
speed in people with Parkinson’s disease [
57
], chronic obstructive pulmonary disease [
58
]
and reduces the risk of cardiovascular mortality [59].
4.2. Which Type of Exercise Training?
There is overwhelming evidence that regular physical activity is associated with
reduced LBP [
2
–
4
,
6
,
52
,
60
]. The most appropriate exercise intervention is still unknown.
Opinions differ over the optimal exercise modalities used to treat LBP. The “active ingre-
dient” of exercise programs is largely unknown, although various exercise options are
available [
2
,
60
,
61
]. Considerably more research is required in order to allow for the devel-
opment and promotion of a wider variety of low cost, but effective exercise programs [
2
,
3
].
Our metaregression demonstrated the benefits of pelvic, leg and trunk stretching, in line
with the literature [
53
]. However, drawing any firm conclusions on the best type of exercise
is impossible because most studies integrated strength and aerobic training, precluding
further analysis (e.g., there was a lack of reference groups that omitted either strength or
aerobic training). The predominance of strength in the selected studies is due to the high
level of proof of its efficacy in the treatment of LBP [
11
,
53
], whereas the benefits aerobic ex-
ercises are more under debate [
3
]. Easily-performed exercises produced noticeable benefits
and supported adherence to home-based exercise programs [
62
]. While aerobic training
was easily achievable at home [
59
], strength training may require more supervision, at
least at the beginning [
63
]. However, strength training is still achievable at home in a wide
range of pathologies [
52
,
57
]. Despite conflicting results in the literature [
2
,
60
] relaxation
and postural exercise seemed ineffective in reducing LBP, as well as education alone [
60
,
64
].
Similarly to center-based exercise [
60
], we found that yoga improved functional limita-
tion, as previous studies also showed. Yoga usually combines a wide variety of exercises
channeled towards improving strength and flexibility [
31
], which may explain its positive
effects on reducing LBP [
3
]. Finally, considering the high impact of long-term adherence
to exercise [
62
], the appropriateness of exercise programs may be best determined by the
preferences of both the patient [6] and therapist [2].
4.3. Supervision, Standardization, Frequency, and Duration of Exercise Training
Several authors claimed that supervised exercise therapy had proven to be effective
in reducing pain and improving functional performance in the treatment of patients with
non-specific LBP [
2
,
5
,
6
,
29
,
60
] whereas others showed that supervision did not significantly
influence final outcomes [
5
,
22
,
42
] but did enhance participants’ satisfaction with care [
42
].
We showed that the best improvements in LBP were achieved through supervised exercise
training. It is important to note that all the home-based exercise programs were prescribed
by a physiotherapist or health professional with a degree-level qualification in exercise
prescription. The majority of the home-based exercise programs in our review incorporated
partial supervision [
5
,
20
,
21
,
25
,
27
–
34
,
36
,
37
,
40
–
42
,
44
,
47
,
48
,
50
], (i.e., the use of a variety of
methods, including home visits by the therapist, occasional group-based sessions at a center
or telephones calls). Some publications suggested that external sources of reinforcement,
like monitoring, may serve to influence physical behavior [
65
]. In addition, applying
supervised home-based exercise is possible to achieve in many ways, helping to optimize

Int. J. Environ. Res. Public Health 2021,18, 8430 16 of 24
effectiveness of the training [
66
]. Importantly, our results were in favor of standardized
exercise compared to individualized exercise, which may be discordant with the literature
based on training in centers [
2
,
26
]. This may be explained by the fact that easily-performed
standardized exercises can promote a better adherence [
62
], and could be more in line
with home exercise, whereas individualized exercise may be more in line with practice in
a center. Lastly, we failed to demonstrate an influence of the volume of exercise on reducing
LBP, despite a strong dose-response relationship between physical activity and its overall
benefits [
2
,
3
]. The absence of such a significant influence on our study may be due to the
wide variety of exercise interventions available, and the inconsistency of the intensity and
duration of exercise [3].
4.4. Predictors of Pain Intensity Improvements
Although no gender differences were found in relation to pain improvement after
exercise in most publication [
53
,
60
], our study found strong evidence that males with LBP
benefited the most from exercise training. Even if the included studies did not report
on observance of exercise, women may lack the time to engage in a daily routine of
training [
67
,
68
]. Fractionalization of an exercise bout into multiple bouts spread across
the day may produce greater benefits and allow for greater adherence [
69
]. Interestingly,
some studies also reported a higher prevalence of LBP in women [
1
,
70
]. In our meta
regressions, age was not associated with pain improvement. This suggests that home-
based exercise, even late in life, can be effective [
71
]. We also demonstrated that the
benefits of exercise were less effective in individuals with a higher body mass index, in line
with the literature [
53
]. Furthermore, individuals using medication, those with no heavy
physical demands at work and individual recovery expectations are important parameters
influencing the prognostics of LBP [
1
,
4
,
53
], although this was seldomly mentioned in the
studies included in our review.
4.5. Limitations
Our study has some limitations. All studies were randomized and patients were not
blinded to the interventions. Several biases could have been introduced via the literature
search and selection procedure. We conducted the meta-analyses on only published
articles, therefore they were theoretically exposed to publication bias. Meta-analyses
also inherit the limitations of the individual studies of which they are composed. The
availability of some individual characteristics limits the ability to assess all potential
treatment effect. Only 11 studies [
22
–
24
,
26
,
30
,
35
,
39
,
43
,
46
,
49
,
51
] had groups exercising only
at home. Hence, comparisons between the efficacy of home-based training versus training
in a center cannot reflect a high level of proof—even if we only included randomized
trials. Similarly, the lack of studies using a control group without exercise precluded
further comparisons. Another major limitation of our meta-analysis is the lack of data on
physical activity levels, as well as on medications used. Additionally, the heterogeneity
between the study protocols and evaluation may have impacted the results. Some short
time-frames (two weeks [
43
]) may also have been too short for a therapeutic effect. Some
studies included targeted population [
21
,
25
,
27
,
30
,
31
,
33
,
43
,
51
], however the large sample
size of over 10,000 individuals of all ages and categories promotes the generalizability of
our results. Even if the weight of studies requires careful thought, because some studies
had several measurement interval times and training duration, sensitivity analyses based
on median or last time of follow-up time demonstrated similar results. Moreover, our
method had the advantage of avoiding selection bias [72].
5. Conclusions
From the literature, it is concluded that home training can be successful if the training
is done at home with friends from a community group taking part. Home-based exercise
training improved pain intensity and functional limitation parameters in participants expe-
riencing LBP. Supervised training and a standardized program seemed beneficial, although

Int. J. Environ. Res. Public Health 2021,18, 8430 17 of 24
insufficient data precluded drawing any robust conclusions around the duration and fre-
quency of sessions. Further dedicated randomized controlled trials in which information
about the type and characteristics of home-based exercise are included are warranted.
Author Contributions:
Conceptualization, C.Q. and F.D.; methodology, J.-B.B.-M. and F.D.; software
and analysis, F.D.; validation, all authors; writing—original draft preparation, C.Q. and F.D.; writing—
review and editing, all authors; supervision, F.D.; funding acquisition, N/A. All authors have read
and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: All available data are included in this article.
Conflicts of Interest: The authors declare no conflict of interest.
Appendix A
Details for the search strategy used within each database
Pubmed
(“low back pain”[MH] OR “low back pain*”[TW] OR “lumbago”[TW] OR “low back
ache”[TW] OR “lower back pain*”[TW] OR “pain, low back”[TW] OR “low backache”[TW]
OR “back pain, low”[TW] OR “back pain, lower”[TW] OR “Low back syndrome”[TW] OR
“Lumbalgia”[TW] OR “Lumbar pain”[TW] OR “LBP”[TW])
AND
(“exercise”[MH] OR “exercise therapy”[MH] OR “exercise movement techniques”[MH]
OR exercise[TW] OR exercises[TW] OR “activity physical”[TW] OR “physical activi-
ties”[TW] OR “physical activity”[TW] OR “sports”[TW] OR “sport” [TW] )
AND
(Homes[TW] OR “housing”[TW]OR Home[TW] OR domiciliary[TW])
Embase
(‘low back pain’/exp OR ‘low back pain *’: ti,ab,kw OR lumbago:ti,ab,kw OR ‘low
back ache’: ti,ab,kw OR ‘lower back pain *’: ti,ab,kw OR ‘pain, low back’: ti,ab,kw OR
‘low backache’: ti,ab,kw OR ‘back pain, low’: ti,ab,kw OR ‘back pain, lower’: ti,ab,kw
OR ‘low back syndrome’: ti,ab,kw OR lumbalgia:ti,ab,kw OR ‘lumbar pain’: ti,ab,kw OR
lbp:ti,ab,kw
AND
(‘exercise’/exp OR ‘kinesiotherapy’/exp OR ‘physical activity’/exp OR ‘sport’/exp
OR exercise *: ti,ab,kw OR ‘exercise therapy’: ti,ab,kw OR ‘exercise movement techniques’:
ti,ab,kw OR ‘activity physical’: ti,ab,kw OR ‘physical activities’: ti,ab,kw OR ‘physical
activity’: ti,ab,kw OR sports:ti,ab,kw OR sport:ti,ab,kw)
AND
(homes:ti,ab,kw OR home:ti,ab,kw OR housing:ti,ab,kw OR domiciliary:ti,ab,kw)
Cochrane
(“low back pain” OR “low back pain*” OR “lumbago” OR “low back ache” OR “lower
back pain*” OR “pain, low back” OR “low backache” OR “back pain, low” OR “back pain,
lower” OR “Low back syndrome” OR “Lumbalgia” OR “Lumbar pain” OR “LBP”)
AND (“exercise” OR “exercise therapy” OR “exercise movement techniques” OR
exercise OR exercises OR “activity physical” OR “physical activities” OR “physical activity”
OR “sports” OR “sport”)
AND (Homes OR “housing” OR Home OR domiciliary)
Science-Direct
“low back pain” AND “exercise” AND “home”.

Int. J. Environ. Res. Public Health 2021,18, 8430 18 of 24
Appendix B
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 17 of 23
AND (Homes OR “housing” OR Home OR domiciliary)
Science-Direct
“low back pain” AND “exercise” AND “home”.
Appendix B
Figure A1. Meta-analysis on the effect of home-based exercise on functional limitation, stratified by
setting (exclusive home-based training versus home-based and other setting).
Figure A1.
Meta-analysis on the effect of home-based exercise on functional limitation, stratified by
setting (exclusive home-based training versus home-based and other setting).

Int. J. Environ. Res. Public Health 2021,18, 8430 19 of 24
Appendix C
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 18 of 23
Appendix C
Figure A2. Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings), supervision, and standardiza-
tion of training), using only the median time of follow-up.
Appendix D
Figure A3. Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the median time of follow-up.
n studies I-squared Weight
(subgroups) (%) (%)
Pain
By location of training
Home 12 (16) 92.4 -1.06 (-1.36 to -0.77) 38.0
Health center + home 14 (25) 91.9 -0.98 (-1.16 to -0.79) 62.0
By supervision of exercise
Totally supervised 4 (8) 91.4 -1.42 (-1.76 to -1.08) 18.4
Partially supervised 14 (21) 90.7 -0.74 (-0.92 to -0.56) 50.9
Not supervised 8 (13) 91.6 -1.08 (-1.39 to -0.77) 30.7
By personnalisati on o f exercise
Individualised 3 (3) 97.1 -1.20 (-2.18 to -0.23) 8.0
Partially individualised 4 (7) 94.2 -0.71 (-1.03 to -0.4) 19.8
Standardized 17 (29) 90.9 -0.99 (-1.18 to -0.8) 72.2
Overall 26 (41) 91.9 - 1.01 (-1.16 to -0.85) 100
Functional limitation
By location of training
Home 12 (17) 89.3 -0.67 (-0.90 to -0.44) 46.9
Health center + home 10 (19) 97.8 -0.95 (-1.37 to -0.53) 53.1
By supervision of exercise
Totally supervised 4 (8) 86.9 -0.80 (-1.06 to -0.54) 19.9
Partially supervised 12 (18) 98.1 -0.85 (-1.30 to -0.40) 45.2
Not supervised 8 (24) 83.3 -0.64 (-0.85 to -0.43) 35.0
By personnalisati on o f exercise
Individualised 2 (2) 99.2 -0.83 (-3.06 to 1.41) 6.4
Partially individualised 4 (7) 96.9 -0.45 (-0.88 to -0.03) 22.7
Standardized 8 (14) 95.5 -0.99 (-1.32 to -0.66) 70.9
Overall 22 (36) 90.2 -0.73 (-0. 86 to -0.59) 100
Effect size
(95% CI)
-1.5 -1 -0 .5 0 0.5
Pain inten sity
p-value
Functional limitation
p-value
(%) (%)
Sociodemographic
Age, per 10-yea r 0.06 ( -0.14 to 0.27) 0. 54 0.05 (- 0.21 to 0.27) 0.68
Sex, per 10% male -0.20 ( -0.33 to -0.07) 0.003 -0.21 (-0.29 to -0.14) <0.01
Body mass index, per 10 km/m2 1. 25 (0.13 to 2.41) 0. 03 -0.22 (-1.61 to 1.15) 0. 74
Smoking, per 10% smokers 0. 06 (-0.61 to 0.73) 0.84 -0.46 ( -1.21 to 0.27) 0. 17
Phyisically active, per 10% people -0.06 (-2.72 to 2.59) 0.82 insufficient data
Married, per 10% 0. 05 (-0.09 to 0.18) 0.38 -0.17 ( -0.42 to 0.05) 0. 10
Duration of symptom, 10-year s 0. 49 (-0.46 to 1.43) 0.29 -0.16 ( -2.41 to 2.11) 0. 87
Parameters of exercise
n weeks training, per 10- week 0.12 (-0.01 to 0.20) 0.07 -1.57 (-2.89 to -0. 16) 0.03
n weeks post-t raining, per 10-w eek -0.01 (-0.07 to 0.05) 0.70 -0.43 (-1.01 to 0.99) 0.11
n min par session, per 10-min 0.03 (- 0.02 to 0.08) 0.24 - 0.12 (-0.41 t o 0.14) 0.33
n set per session, per 10-session 0.13 (-0.29 to 0.50) 0.48 0.05 (- 0.29 to 0.41) 0.70
n session by weeks, per 10-session 0.93 ( 0.03 to 1.80) 0.04 0.19 (- 1.01 to 1.39) 0.74
Type of exer cise, yes vs no
Education -0.14 ( -0.57 to 0.29) 0. 53 0.05 (- 0.53 to 0.63) 0.86
Aerobic -0.31 ( -0.74 to 0.11) 0. 15 -0.40 (-0.98 to 0.18) 0.16
Strenght 0.10 (-0. 36 to 0.56) 0.67 0.29 ( -0.28 to 0.85) 0. 30
Stretching -0.10 (-0.58 to 0.38) 0.68 0.53 (-0.09 to 1.16) 0.09
Relaxation 0.43 ( -0.04 to 0.91) 0. 07 -0.42 (-1.11 to 0.28) 0.23
Postural exercise 0.59 ( 0.14 to 1.04) 0.012 -0.47 (-1.33 to 0.39) 0.28
Yoga 0.41 (- 0.39 to 1.21) 0.31 - 0.85 (-1.83 t o 0.12) 0.08
Details of st rengthening, yes vs no
pelvic muscle strengthening 0.03 (-0.42 to 0.48) 0.89 -0.23 (-1.01 to 0.55) 0.55
legs strengthening 0.41 ( -0.19 to 1.01) 0. 17 -0.10 (-0.68 to 0.46) 0.70
abdominal strengthening -0.20 (-0.64 to 0.23) 0.35 -0.01 ( -0.65 to 0.64) 0. 98
Details of stretching, yes vs no
Trunk streching -0.62 (-1.12 to -0.12) 0.017 -0.31 (-0.93 to 0.31) 0.31
Abdominal stretching 0.15 (-0.87 to 1.18) 0.76 -0.05 (-1.13 to 1.03) 0. 92
Pelvic stretching -0. 89 (-1.41 to -0.38) 0.001 -0.43 (-1.11 to 0.24) 0.20
Leg stretching -0.37 ( -0.85 to 0.11) 0. 13 0.10 (- 0.52 to 0.73) 0.74
Standardized / individualised
Totally ind. vs standardised -0.19 (-1.02 to 0.64) 0.65 0.19 (- 0.88 to 1.25) 0.73
Totally ind. vs partially ind. -0.48 ( -1.42 to 0.45) 0. 30 -0.35 (-1.51 to 0.80) 0.54
Partially ind. vs standardized 0.29 (-0 .07 to 1.04) 0.086 0. 54 (-0.08 to 1.16) 0.09
Supervised exercises
Totally vs partially supervised -0.71 (-1.23 to -0. 19) 0.009 0.01 (-0.57 to 0. 58) 0.98
Totally vs not supervised -0.38 ( -0.94 to 0.19) 0.18 -0.20 (-0.79 to 0.40) 0.51
Partially vs not supervised 0.33 (-0.27 to 0.86) 0.30 -0.20 (-0.68 to 0.28) 0.40
Location of training
Home + other setting vs home 0.06 (-0.38 to 0.51) 0.78 0.27 (-0. 19 to 0.73) 0.24
Coefficient Coefficient
(95% CI) (95% CI)
Figure A2.
Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings), supervision, and standardization
of training), using only the median time of follow-up.
Appendix D
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 18 of 23
Appendix C
Figure A2. Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings), supervision, and standardiza-
tion of training), using only the median time of follow-up.
Appendix D
Figure A3. Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the median time of follow-up.
n studies I-squared Weight
(subgroups) (%) (%)
Pain
By location of training
Home 12 (16) 92.4 -1.06 (-1.36 to -0.77) 38.0
Health center + home 14 (25) 91.9 -0.98 (-1.16 to -0.79) 62.0
By supervision of exercise
Totally supervised 4 (8) 91.4 -1.42 (-1.76 to -1.08) 18.4
Partially supervised 14 (21) 90.7 -0.74 (-0.92 to -0.56) 50.9
Not supervised 8 (13) 91.6 -1.08 (-1.39 to -0.77) 30.7
By personnalisati on o f exercise
Individualised 3 (3) 97.1 -1.20 (-2.18 to -0.23) 8.0
Partially individualised 4 (7) 94.2 -0.71 (-1.03 to -0.4) 19.8
Standardized 17 (29) 90.9 -0.99 (-1.18 to -0.8) 72.2
Overall 26 (41) 91.9 - 1.01 (-1.16 to -0.85) 100
Functional limitation
By location of training
Home 12 (17) 89.3 -0.67 (-0.90 to -0.44) 46.9
Health center + home 10 (19) 97.8 -0.95 (-1.37 to -0.53) 53.1
By supervision of exercise
Totally supervised 4 (8) 86.9 -0.80 (-1.06 to -0.54) 19.9
Partially supervised 12 (18) 98.1 -0.85 (-1.30 to -0.40) 45.2
Not supervised 8 (24) 83.3 -0.64 (-0.85 to -0.43) 35.0
By personnalisati on o f exercise
Individualised 2 (2) 99.2 -0.83 (-3.06 to 1.41) 6.4
Partially individualised 4 (7) 96.9 -0.45 (-0.88 to -0.03) 22.7
Standardized 8 (14) 95.5 -0.99 (-1.32 to -0.66) 70.9
Overall 22 (36) 90.2 -0.73 (-0. 86 to -0.59) 100
Effect size
(95% CI)
-1.5 -1 -0 .5 0 0.5
Pain inten sity
p-value
Functional limitation
p-value
(%) (%)
Sociodemographic
Age, per 10-yea r 0.06 ( -0.14 to 0.27) 0. 54 0.05 (- 0.21 to 0.27) 0.68
Sex, per 10% male -0.20 ( -0.33 to -0.07) 0.003 -0.21 (-0.29 to -0.14) <0.01
Body mass index, per 10 km/m2 1. 25 (0.13 to 2.41) 0. 03 -0.22 (-1.61 to 1.15) 0. 74
Smoking, per 10% smokers 0. 06 (-0.61 to 0.73) 0.84 -0.46 ( -1.21 to 0.27) 0. 17
Phyisically active, per 10% people -0.06 (-2.72 to 2.59) 0.82 insufficient data
Married, per 10% 0. 05 (-0.09 to 0.18) 0.38 -0.17 ( -0.42 to 0.05) 0. 10
Duration of symptom, 10-year s 0. 49 (-0.46 to 1.43) 0.29 -0.16 ( -2.41 to 2.11) 0. 87
Parameters of exercise
n weeks training, per 10- week 0.12 (-0.01 to 0.20) 0.07 -1.57 (-2.89 to -0. 16) 0.03
n weeks post-t raining, per 10-w eek -0.01 (-0.07 to 0.05) 0.70 -0.43 (-1.01 to 0.99) 0.11
n min par session, per 10-min 0.03 (- 0.02 to 0.08) 0.24 - 0.12 (-0.41 t o 0.14) 0.33
n set per session, per 10-session 0.13 (-0.29 to 0.50) 0.48 0.05 (- 0.29 to 0.41) 0.70
n session by weeks, per 10-session 0.93 ( 0.03 to 1.80) 0.04 0.19 (- 1.01 to 1.39) 0.74
Type of exer cise, yes vs no
Education -0.14 ( -0.57 to 0.29) 0. 53 0.05 (- 0.53 to 0.63) 0.86
Aerobic -0.31 ( -0.74 to 0.11) 0. 15 -0.40 (-0.98 to 0.18) 0.16
Strenght 0.10 (-0. 36 to 0.56) 0.67 0.29 ( -0.28 to 0.85) 0. 30
Stretching -0.10 (-0.58 to 0.38) 0.68 0.53 (-0.09 to 1.16) 0.09
Relaxation 0.43 ( -0.04 to 0.91) 0. 07 -0.42 (-1.11 to 0.28) 0.23
Postural exercise 0.59 ( 0.14 to 1.04) 0.012 -0.47 (-1.33 to 0.39) 0.28
Yoga 0.41 (- 0.39 to 1.21) 0.31 - 0.85 (-1.83 t o 0.12) 0.08
Details of st rengthening, yes vs no
pelvic muscle strengthening 0.03 (-0.42 to 0.48) 0.89 -0.23 (-1.01 to 0.55) 0.55
legs strengthening 0.41 ( -0.19 to 1.01) 0. 17 -0.10 (-0.68 to 0.46) 0.70
abdominal strengthening -0.20 (-0.64 to 0.23) 0.35 -0.01 ( -0.65 to 0.64) 0. 98
Details of stretching, yes vs no
Trunk streching -0.62 (-1.12 to -0.12) 0.017 -0.31 (-0.93 to 0.31) 0.31
Abdominal stretching 0.15 (-0.87 to 1.18) 0.76 -0.05 (-1.13 to 1.03) 0. 92
Pelvic stretching -0. 89 (-1.41 to -0.38) 0.001 -0.43 (-1.11 to 0.24) 0.20
Leg stretching -0.37 ( -0.85 to 0.11) 0. 13 0.10 (- 0.52 to 0.73) 0.74
Standardized / individualised
Totally ind. vs standardised -0.19 (-1.02 to 0.64) 0.65 0.19 (- 0.88 to 1.25) 0.73
Totally ind. vs partially ind. -0.48 ( -1.42 to 0.45) 0. 30 -0.35 (-1.51 to 0.80) 0.54
Partially ind. vs standardized 0.29 (-0 .07 to 1.04) 0.086 0. 54 (-0.08 to 1.16) 0.09
Supervised exercises
Totally vs partially supervised -0.71 (-1.23 to -0. 19) 0.009 0.01 (-0.57 to 0. 58) 0.98
Totally vs not supervised -0.38 ( -0.94 to 0.19) 0.18 -0.20 (-0.79 to 0.40) 0.51
Partially vs not supervised 0.33 (-0.27 to 0.86) 0.30 -0.20 (-0.68 to 0.28) 0.40
Location of training
Home + other setting vs home 0.06 (-0.38 to 0.51) 0.78 0.27 (-0. 19 to 0.73) 0.24
Coefficient Coefficient
(95% CI) (95% CI)
Figure A3.
Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the median time of follow-up.

Int. J. Environ. Res. Public Health 2021,18, 8430 20 of 24
Appendix E
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 19 of 23
Appendix E
Figure A4. Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings, supervision, and standardiza-
tion of training), using only the last time of follow-up.
Appendix F
Figure A5. Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the last time of follow-up.
n studies I-squared Weight
(subgroups) (%) (%)
Pain
By location of training
Home 12 (16) 93 -1.09 (-1.40 to -0.78) 38
Health center + home 14 (25) 91.5 -0.95 (-1.13 to -0.76) 62
By supervision of exercise
Totally supervised 4 (8) 89.6 -1.44 (-1.74 to -1.13) 18.4
Partially supervised 14 (21) 90 -0.72 (-0.90 to -0.54) 50.9
Not supervised 8 (13) 91.4 -1.03 (-1.33 to -0.73) 30.7
By personnalisation of exercise
Individualised 3 (3) 94.9 -1.34 (-2.42 to -0.26) 8
Partially individualised 4 (7) 87.2 -0.55 (-0.75 to -0.34) 19.8
Standardized 17 (29) 91.2 -1.02 (-1.21 to -0.82) 72.2
Overall 26 (41) 92.1 -1.00 (-1.16 to -0.85) 100
Functional limitation
By location of training
Home 12 (17) 89.3 -0.69 (-0.93 to -0.46) 46.9
Health center + home 10 (19) 97.8 -0.93 (-1.34 to -0.52) 53.1
By supervision of exercise
Totally supervised 5 (9) 85.3 -0.76 (-1.06 to -0.54) 19.9
Partially supervised 13 (42) 97.2 -0.88 (-1.31 to -0.44) 45.2
Not supervised 8 (24) 77.1 -0.60 (-0.80 to -0.41) 35.0
By personnalisation of exercise
Individualised 2 (4) 97.8 -0.89 (-3.00 to 1.21) 6.4
Partially individualised 4 (22) 95.2 -0.35 (-0.66 to -0.04) 22.8
Standardized 14 (43) 94.2 -1.02 (-1.35 to -0.69) 70.9
Overall
22 (36)
90.2
-0.73 (-0.86 to -0.59) 100
Effect size
(95% CI)
-1.5 -1 -0 .5 0 0.5
Pain intensity
p-value
Functional limita tion
p-value
(%) (%)
Sociodemographic
Age, per 10-year 0.12 ( -0.09 to 0.33) 0.24 0.12 ( -0.11 to 0.31) 0.40
Sex, per 10% male -0. 20 (-0.33 t o -0.07) 0.04 -0.20 (-0.37 to 0.01) <0.01
Body mass index, per 10 km/m2 1.35 (0.23 to 2.47) 0.02 -0.12 (-1.49 to 0.12) 0.86
Smoking , per 10% smok ers 0.03 (-0.42 t o 0.48) 0.88 -0.22 (-0. 4 to -0.01) 0.64
Phyisical ly active, pe r 10% people -0.11 (- 2.29 to 2.08) 0.65
Married, p er 10% 0.05 ( -0.08 to 0.18) 0.38 0.00 ( -0.09 to 0.14) 0.10
Duration of symptom, 10-years 0.53 ( -0.42 to 1.49) 0.26 0.01 ( -0.78 to 0.95) 0.86
Parameters of exercise
n weeks training, p er 10-week 0.11 (-0.02 to 0.22) 0.11 0.1 9 (-0.32 to 0.67) 0.45
n weeks post-training, per 10-week -0.02 (-0.11 to 0.04) 0.46 -0.03 (-0.14 to 0.08) 0.06
n min par session, per 10-min 0.03 (-0. 02 to 0.07) 0.31 0.01 (-0. 05 to 0.07) 0.68
n set per session, per 10-session 0.13 (-0.29 to 0.49) 0.74 0.05 (-0.19 to 0.29) 0.62
n session by weeks, per 10-session 0.67 (- 0.26 to 1.61) 0.16 -0.01 (-0.92 to 0.91) 0.97
Type of exercise, yes vs n o
Educat ion -0.06 ( -0.48 to 0.39) 0.80 0.23 (- 0.25 to 0.71) 0.33
Aerobic -0.20 (- 0.65 to 0.15) 0.37 -0.08 (-0.56 to 0.41) 0.27
Strenght 0.17 (-0.32 to 0.64) 0.47 0.39 (-0.08 to 0.86) 0.10
Stretching -0.06 (-0.55 to 0.44) 0.82 0.25 (-0.28 to 0.79) 0.34
Relaxation 0.44 (-0. 04 to 0.93) 0.07 -0.03 (-0.62 to 0. 57) 0.21
Postural exercise 0.54 (0.07 to 1.01) 0.03 0.23 (-0.32 to 0.79) 0.05
Yoga 0.41 (- 0.41 to 1.22) 0.33 -0.9 9 (-1.94 t o -0.04) 0.004
Details of strengthening, yes vs no
pelvic mu scle stren gthening 0.12 ( -0.34 to 0.58) 0.59 0.24 (- 0.25 to 0.72) 0.17
legs strengthening 0.47 (-0.13 to 1.07) 0.12 0.25 (-0.49 to 0.99) 0.51
abdomin al strengt hening -0. 14 (-0.59 t o 0.31) 0.52 0 .14 (-0.33 to 0.61) 0.54
Details of stretching, yes vs no
Trunk streching -0.63 (-1.15 to -0.12) 0.02 0.25 (-0.28 to 0.79) 0.06
Abdominal stretchin g 0.15 (- 0.89 to 1.19) 0.77 -0. 21 (-1.26 t o 0.83) 0.68
Pelvic str etching -0.90 (-1.43 to -0. 38) 0.01 -0.57 (-1. 21 to 0.05) 0.07
Leg stretching -0.39 (-0.88 to 0.09) 0.11 -0.11 (-0.68 to 0.47) 0.71
Standardized / individualised
Totally ind. vs standardised -0.02 (-0.43 to 0.40) 0.47 0.15 (-0.89 to 1.19) 0.77
Totally ind. vs partially ind. -0.30 (-0.74 to 0.14) 0.09 -0.52 (-1.65 to 0.62) 0.35
Partially ind. vs standardized 0.29 (0.03 to 0.55) 0.09 0.67 (0.06 to 1.28) 0.031
Supervised exercises
Totally vs partially supervised -0.50 (-0.74 to -0.25) 0.005 -0.23 (-0.82 to 0.61) 0.91
Totally vs not sup ervised -0. 28 (-0.56 t o -0.01) 0.11 -0. 23 (-0.82 t o 0.37) 0.45
Partially vs not supervised 0.22 (-0.02 to 0.50) 0.17 -0.26 (-0.73 to 0.22) 0.28
Location of training
Home + ot her setting vs home 0.07 ( -0.24 to 0.40) 0.66 -0. 22 (-0.69 to 0.25) 0.35
Coefficien t Coeffici ent
(95% CI) (95% CI)
-0.75 0 0.75 -0.75 0 0.75
Figure A4.
Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings, supervision, and standardization
of training), using only the last time of follow-up.
Appendix F
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 19 of 23
Appendix E
Figure A4. Summary of meta-analysis on the effect of home-based exercise on pain intensity and functional limitation,
stratified by setting (exclusive home-based training versus home-based and other settings, supervision, and standardiza-
tion of training), using only the last time of follow-up.
Appendix F
Figure A5. Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the last time of follow-up.
n studies I-squared Weight
(subgroups) (%) (%)
Pain
By location of training
Home 12 (16) 93 -1.09 (-1.40 to -0.78) 38
Health center + home 14 (25) 91.5 -0.95 (-1.13 to -0.76) 62
By supervision of exercise
Totally supervised 4 (8) 89.6 -1.44 (-1.74 to -1.13) 18.4
Partially supervised 14 (21) 90 -0.72 (-0.90 to -0.54) 50.9
Not supervised 8 (13) 91.4 -1.03 (-1.33 to -0.73) 30.7
By personnalisation of exercise
Individualised 3 (3) 94.9 -1.34 (-2.42 to -0.26) 8
Partially individualised 4 (7) 87.2 -0.55 (-0.75 to -0.34) 19.8
Standardized 17 (29) 91.2 -1.02 (-1.21 to -0.82) 72.2
Overall 26 (41) 92.1 -1.00 (-1.16 to -0.85) 100
Functional limitation
By location of training
Home 12 (17) 89.3 -0.69 (-0.93 to -0.46) 46.9
Health center + home 10 (19) 97.8 -0.93 (-1.34 to -0.52) 53.1
By supervision of exercise
Totally supervised 5 (9) 85.3 -0.76 (-1.06 to -0.54) 19.9
Partially supervised 13 (42) 97.2 -0.88 (-1.31 to -0.44) 45.2
Not supervised 8 (24) 77.1 -0.60 (-0.80 to -0.41) 35.0
By personnalisation of exercise
Individualised 2 (4) 97.8 -0.89 (-3.00 to 1.21) 6.4
Partially individualised 4 (22) 95.2 -0.35 (-0.66 to -0.04) 22.8
Standardized 14 (43) 94.2 -1.02 (-1.35 to -0.69) 70.9
Overall
22 (36)
90.2
-0.73 (-0.86 to -0.59) 100
Effect size
(95% CI)
-1.5 -1 -0 .5 0 0.5
Pain intensity
p-value
Functional limita tion
p-value
(%) (%)
Sociodemographic
Age, per 10-year 0.12 ( -0.09 to 0.33) 0.24 0.12 ( -0.11 to 0.31) 0.40
Sex, per 10% male -0. 20 (-0.33 t o -0.07) 0.04 -0.20 (-0.37 to 0.01) <0.01
Body mass index, per 10 km/m2 1.35 (0.23 to 2.47) 0.02 -0.12 (-1.49 to 0.12) 0.86
Smoking , per 10% smok ers 0.03 (-0.42 to 0.48) 0. 88 - 0.22 (-0.4 to -0.01) 0.64
Phyisical ly active, pe r 10% people -0.11 (- 2.29 to 2.08) 0.65
Married, p er 10% 0.05 ( -0.08 to 0.18) 0.38 0.00 ( -0.09 to 0.14) 0.10
Duration of symptom, 10-years 0.53 ( -0.42 to 1.49) 0.26 0.01 ( -0.78 to 0.95) 0.86
Parameters of exercise
n weeks training, p er 10-week 0.11 (-0.02 to 0. 22) 0.11 0.19 (-0.32 to 0.67) 0.45
n weeks post-training, per 10-week -0.02 (-0.11 to 0.04) 0.46 -0.03 (-0.14 to 0.08) 0.06
n min par session, per 10-min 0.03 (-0. 02 to 0.07) 0.31 0.01 (-0. 05 to 0.07) 0.68
n set per session, per 10-session 0.13 (-0.29 to 0.49) 0.74 0.05 (-0.19 to 0.29) 0.62
n session by weeks, per 10-session 0.67 (- 0.26 to 1.61) 0.16 -0.01 (-0.92 to 0.91) 0.97
Type of exercise, yes vs n o
Educat ion -0.06 ( -0.48 to 0.39) 0.80 0.23 (- 0.25 to 0.71) 0.33
Aerobic -0.20 (- 0.65 to 0.15) 0.37 -0.08 (-0.56 to 0.41) 0.27
Strenght 0.17 (-0.32 to 0.64) 0.47 0.39 (-0.08 to 0.86) 0.10
Stretching -0.06 (-0.55 to 0.44) 0.82 0.25 (-0.28 to 0.79) 0.34
Relaxation 0.44 (-0. 04 to 0.93) 0.07 -0.03 (-0.62 to 0. 57) 0.21
Postural exercise 0.54 (0.07 to 1.01) 0.03 0.23 (-0.32 to 0.79) 0.05
Yoga 0.41 (- 0.41 to 1.22) 0.33 -0.9 9 (-1.94 t o -0.04) 0.004
Details of strengthening, yes vs no
pelvic mu scle stren gthening 0.12 ( -0.34 to 0.58) 0.59 0.24 (- 0.25 to 0.72) 0.17
legs strengthening 0.47 (-0.13 to 1.07) 0.12 0.25 (-0.49 to 0.99) 0.51
abdomin al strengt hening -0. 14 (-0.59 t o 0.31) 0.52 0 .14 (-0.33 to 0.61) 0.54
Details of stretching, yes vs no
Trunk streching -0.63 (-1.15 to -0.12) 0.02 0.25 (-0.28 to 0.79) 0.06
Abdominal stretchin g 0.15 (- 0.89 to 1.19) 0.77 -0. 21 (-1.26 t o 0.83) 0.68
Pelvic str etching -0.90 (-1.43 to -0. 38) 0.01 -0.57 (-1. 21 to 0.05) 0.07
Leg stretching -0.39 (-0.88 to 0.09) 0.11 -0.11 (-0.68 to 0.47) 0.71
Standardized / individualised
Totally ind. vs standardised -0.02 (-0.43 to 0.40) 0.47 0.15 (-0.89 to 1.19) 0.77
Totally ind. vs partially ind. -0.30 (-0.74 to 0.14) 0.09 -0.52 (-1.65 to 0.62) 0.35
Partially ind. vs standardized 0.29 (0.03 to 0.55) 0.09 0.67 (0.06 to 1.28) 0.031
Supervised exercises
Totally vs partially supervised -0.50 (-0.74 to -0.25) 0.005 -0.23 (-0.82 to 0.61) 0.91
Totally vs not sup ervised -0. 28 (-0.56 t o -0.01) 0.11 -0. 23 (-0.82 t o 0.37) 0.45
Partially vs not supervised 0.22 (-0.02 to 0.50) 0.17 -0.26 (-0.73 to 0.22) 0.28
Location of training
Home + ot her setting vs home 0.07 ( -0.24 to 0.40) 0.66 -0. 22 (-0.69 to 0.25) 0.35
Coefficien t Coeffici ent
(95% CI) (95% CI)
-0.75 0 0.75 -0.75 0 0.75
Figure A5.
Metaregressions (i.e., putative influencing variables on pain intensity and functional limitation following
home-based exercise in LBP), using only the last time of follow-up.

Int. J. Environ. Res. Public Health 2021,18, 8430 21 of 24
Appendix G
Int. J. Environ. Res. Public Health 2021, 18, x FOR PEER REVIEW 20 of 23
Appendix G
Figure A6. Funnel plot (meta-funnel) for effect size of home-based exercise on pain intensity and
functional limitation, in low back pain. Each dot represents a single study, with its corresponding
effect size (x-axis) and its associated standard error of the effect estimate (y-axis). Large high-pow-
ered studies are placed towards the top, and smaller low-powered studies towards the bottom. The
plot should ideally resemble a pyramid or inverted funnel, with scatter due to sampling variation.
Studies outside the funnel plot are likely to present bias.
Figure A6.
Funnel plot (meta-funnel) for effect size of home-based exercise on pain intensity and
functional limitation, in low back pain. Each dot represents a single study, with its corresponding
effect size (x-axis) and its associated standard error of the effect estimate (y-axis). Large high-powered
studies are placed towards the top, and smaller low-powered studies towards the bottom. The plot
should ideally resemble a pyramid or inverted funnel, with scatter due to sampling variation. Studies
outside the funnel plot are likely to present bias.

Int. J. Environ. Res. Public Health 2021,18, 8430 22 of 24
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