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Vol. 56 - No. 5 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE 585
European Journal of Physical and Rehabilitation
Medicine
October 2020
Vol. 56 - No. 5
ORIGINAL ARTICLE
How effective and efcient are different
exercise patterns in reducing back pain?
Gerhard MÜLLER *, Lisa LYSSENKO, Marco GIURGIU, Manuela PFINDER, Michael CLEMENT,
Andreas KAISERAUER, Monika HEINZEL-GUTENBRUNNER, Thomas KOHLMANN, Klaus BÖS
Department of Product Management, AOK Baden-Wuerttemberg, Bruchsal, Germany
* Corresponding author: Gerhard Müller, Department of Product Management, AOK Baden-Wuerttemberg, Bahnhofstrasse 12, 76646 Bruchsal, Germany.
E-mail: gerhard.mueller@bw.aok.de
ABSTRACT
BACKGROUND: Exercise is considered an effective intervention to relieve chronic back pain. However, it is still unknown whether specic
exercise patterns vary in terms of their efciency and effectiveness.
AIM: To investigate the differential health and economic effects of intensity, specicity and degree of subjective perceived physical exertion
across ve exercise patterns (endurance, gymnastics, tness, back gymnastics, multimodal back exercise) in adults with back pain.
DESIGN: Longitudinal observational cohort study over a period of 24 months.
SETTING: Various non-therapeutic exercise facilities (e.g. outdoor, tness centers, health insurance programs, sports clubs) across one federal
state of Germany (Baden-Wuerttemberg).
POPULATION: Adults with back pain (N.=2,542, Mean =46.9 years, 66% females, graded chronic back pain [GCPS] 1=40.5%, GCPS 2=27.3%,
GCPS 3=20.7%, GCPS 4=11.5%).
METHODS: Self-reported back pain (functional restrictions and pain = back pain function score, [BPFS]) and characteristics of exercising
behavior (frequency, duration, type, physical exertion) were assessed at baseline and at 6, 12, 18 and 24 months. Direct medical costs for back
disorders (international classication of diseases, dorsopathies: M40–M54) were compiled from health insurance records.
RESULTS: Moderate- to high-intensity exercise patterns were effective in reducing back pain, particularly at lower levels of subjective per-
ceived physical exertion. At these intensity levels, multimodal back exercise (i.e. exercising the spine-stabilizing muscles specically, ergonomic
training) was 14.5 times more effective than non-back specic tness exercise in reducing BPFS. The benecial effects of both exercise types
increased with the initial severity of back pain. However, only multimodal back exercise (moderate- to high-intensity/high back specicity) was
associated with a signicant decrease in direct medical costs for back pain.
CONCLUSIONS: Targeted exercise of the spine-stabilizing musculature at moderate to high intensities without maximum perceived exertion is
effective and efcient in reducing back pain.
CLINICAL REHABILITATION IMPACT: The combination of high-intensity and high-specicity exercises yielded a signicant reduction in
medical costs. However, the intensities in terms of muscular load in endurance training and gymnastics may not be sufcient to reduce back
pain effectively.
(Cite this article as: Müller G, Lyssenko L, Giurgiu M, Pnder M, Clement M, Kaiserauer A, et al. How effective and efcient are different exercise
patterns in reducing back pain? Eur J Phys Rehabil Med 2020;56:585-93. DOI: 10.23736/S1973-9087.20.05975-4)
Key words: Exercise; Physical exertion; Back pain; Cohort studies.
European Journal of Physical and Rehabilitation Medicine 2020 October;56(5):585-93
DOI: 10.23736/S1973-9087.20.05975-4
MÜLLER
IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN
© 2020 EDIZIONI MINERVA MEDICA
Online version at http://www.minervamedica.it
Back pain is responsible for most of the years lived with
disability (YLD) worldwide and has a lifetime preva-
lence of over 70% in industrialized countries.1, 2 The as-
sociated medical costs are estimated to amount up to 10%
of the respective gross domestic product (GDP), underlin-
ing the claim that effective interventions not only allevi-
ate pain for individuals but also bear considerable societal
relevance.3-6
Physical activity has been shown to effectively reduce
chronic back pain in a substantial number of studies and
is consistently recommended for the management of non-
specic low back pain in clinical guidelines.7-10 However,
its mechanisms of action are not yet well understood.7, 11-18
In physiological models, the pain-reducing effect is as-
sumed to be related to neuronal adaptations associated with
increases in trunk strength, stability and exibility.19 From
a psychological-cognitive perspective, the combination of
physical activity and pain reduction supposedly generates
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MÜLLER IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN
586 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE October 2020
Materials and methods
Study design and sample
The study was conducted as part of a nonrandomized
multi-center evaluation trial on the effectiveness of a mul-
timodal back exercise program compared to standard care
for back pain, with assessments at baseline (t0) and after
6, 12, 18 and 24 months (t1, t2, t3, t4).29 The inclusion
criteria were a minimum age of 16 years and the presence
of back pain (graded chronic pain status [GCPS]>0). The
only exclusion criterion was a medical contraindication
to physical exercise. The study was approved by the ethi-
cal review committee at the University of Greifswald (ID
33/08).
Out of 4888 contacted study participants, 2920 insur-
ance holders agreed to take part in the evaluation study,
of which 87% (N.=2542) were included in the analyses
presented here. Reasons for exclusion were the absence of
back pain (GCPS=0; N.=114), missing data on the back-
pain function score ([BPFS]; N.=123) and missing data
on medical costs (N.=141). Only the response rate for the
questionnaires decreased with each assessment date (ques-
tionnaires data: t1 67%, t2 61%, t3 57%, t4 53%; cost data:
t1-t4 100%) see Figure 1. The resulting data are nonex-
perimental data corresponding to the design of an observa-
tional cohort study. Participants are not grouped according
to their type of exercise; each participant is included with
his amount of training in each of the ve categories (see
outcome measures).
Outcome measures
Back pain was assessed with the German version of the
Chronic Pain Grade questionnaire,30 a standardized self-
report instrument, asking for pain intensity (3 items),
pain-related functional impairment (3 items), the num-
ber of days on which pain was present (1 item) and im-
peded performance of routine daily activities (1 item).
The original version recommends a categorization into
ve levels of GCPS:30 no back pain, low pain intensity,
high pain intensity, moderate functional impairment and
severe functional impairment. However, the distinction
between pain intensity and pain-related disability has
been critically discussed.31 A preliminary inspection of
the data structure in our sample similarly revealed one
single factor with an eigenvalue >1 by means of an ex-
ploratory factor analysis. Consequently, we combined the
scores for pain intensity and functioning items for a mean
total score, which ranged from 0 to 10 (Back Pain Func-
tion Score, BPFS).32
a self-reinforcing upward spiral of improvements in self-
efcacy beliefs, self-management behaviors, psychosocial
functioning and overall well-being.8, 20 However, empiri-
cal results on the inuence of type and intensity of exer-
cise, as well as the subjective degree of perceived physical
exertion (following Borg21assessment of physical exer-
tion from any exertion at all up to maximum exertion on
a scale from 0 to 10), are inconsistent,8, 17-22 and empirical
evidence on the question of whether a movement-induced
reduction in back pain affects direct medical costs is rather
fragmentary.7, 9, 12, 23-25 Despite the double-digit number of
systematic reviews published on the topic, there is no con-
sensus on the relative effectiveness of different exercise
patterns, and the question of which elements of an inter-
vention are particularly decisive for the pain-reducing ef-
fect remains unanswered. Some authors, e.g. Haag et al.,26
argue that “there is still no evidence that anyone specic
approach is the most favorable,” while others emphasize
particular exercise characteristics; for example, Smeets et
al.18 concluded that “specic low back muscle strengthen-
ing exercises of sufcient intensity and frequency to fulll
the exercise physiology criteria show moderate evidence
that they are more effective compared to less intensive ex-
ercises.” This discrepancy seems to be affected by aspects
such as the sample populations, experimental procedures
and comparators in individual studies, which typically
investigate a limited variety of exercise patterns in clini-
cally homogenous sample populations. This approach has
a rather paradoxical effect on the integration of evidence:
systematic reviews/meta-analyses encounter high hetero-
geneity between samples and low comparability of exer-
cise patterns.27
The primary aim of this investigation was to analyze
the relative effectiveness and efciency of different exer-
cise patterns in reducing back pain. The structure of the
German statutory health insurance system provides a con-
venient context for pragmatic research designs.28 Along-
side the implementation of a specic program for back
pain prevention across one federal state of Germany, we
conducted a longitudinal observational study in a socio-
demographically diverse sample including a wide vari-
ety of exercise patterns, ranging from specic medically
indicated training of the spine-stabilizing musculature to
incidental leisure time exercises. In this paper, we address
the following questions: rst, how effective are different
exercise patterns in reducing back pain? Second, does the
degree of subjective perceived physical exertion inuence
the effects? Third, how do these parameters impact the
economic perspective?
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cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher.
IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN MÜLLER
Vol. 56 - No. 5 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE 587
• Gymnastics: exercises to improve agility, coordina-
tion and strength across body parts at a low to moderate
level of intensity;
• Fitness: exercises similar to those above mentioned at
a moderate to high level of intensity;
• Back gymnastics: exercises specically designed to
improve the strength and mobility of the spine-stabilizing
musculature at a low to moderate level of intensity;
• Multimodal back exercise (MMBE): exercises com-
parable to those above mentioned and performed on spe-
cialized exercise equipment at a moderate to high level
of intensity and combined with ergonomic exercises
for everyday motor activities (sitting, standing, lifting
loads).32
Cost data were compiled directly from the insurance
fund records, thus representing the actual net costs per
participant attributable to back pain as coded in the Inter-
national Classication of Diseases (ICD-10; Chapter XIII:
Diseases of the musculoskeletal system and connective
tissue, M40-M54). Costs include in- and outpatient acute
care as well as rehabilitative treatment, statutory sick leave
benets, medically prescribed supplementary treatments
(e.g. hydrotherapy, electrotherapeutic physiotherapy, and
massages), and medication for pain relief as classied in
the German Pharmaceutical Atlas (e.g. antiphlogistic, an-
tirheumatics, and muscle relaxants).34 Costs are expressed
in euros and relate to a six-month time period preceding
each assessment time point.
Statistical analyses
Hierarchical linear models (HLMs) with random intercepts
were chosen to analyze the effects of exercise patterns on
health and economic outcomes. In order to analyze the
longitudinal data resulting from observing the participants
Exercise patterns were assessed via a list of different
exercises (e.g. walking, biking, and an additional blank
space for other sports, such as Thai Bo or aqua tness),
on which participants indicated the frequencies, durations
and subjective perceived physical exertion levels of their
activities during the six months preceding each assessment
(following Borg21), regardless of whether an activity was
performed with the explicit aim of reducing back pain.
The participants reported within the questionnaire their
individually performed exercise pattern. They were not as-
signed to a specic exercise pattern.
The type of exercise was dened by a two-step rating
process. A team of experts rst developed a categorical
scheme with the predened criteria intensity (i.e. muscu-
lar load; ratings based on load and velocity of movements:
exercise that uses a heavier load and/or faster velocity
have a greater exercise intensity33) and specicity of ex-
ercise (i.e. spine-stabilizing exercise) (Figure 2). Subse-
quently, each activity was assigned to one of the following
categories:
• Endurance training: physical activities characterized
by a low level of intensity and maintained over a pro-
longed period of time, often aimed at strengthening the
cardiovascular system;
Figure 1.—Participant owchart.
Figure 2.—Classication of exercise patterns.
Insurance holders asked for participation
(N.=4888)
No consent form (N.=1968)
Exclusions (N.=378)
- Did not meet inclusion criteria (GCPS>0) (N.=114)
- Lacked data for calculating the BPFS (N.=123)
- Incomplete cost data (N.=141)
- Cost data analyzed (N.=2542)
- Questionnaire data analyzed (N.=2542)
T0
- Cost data analyzed (N.=2542)
- Questionnaire data analyzed (N.=1711)
T1
- Cost data analyzed (N.=2542)
- Questionnaire data analyzed (N.=1551)
T2
- Cost data analyzed (N.=2542)
- Questionnaire data analyzed (N.=1448)
T3
- Cost data analyzed (N.=2542)
- Questionnaire data analyzed (N.=1350)
T4
SPECIFICITY
(Spine-stabilization exercise)
high
low
low high
INTENSITY
(Muscle load)
Back gymnastics
Various gymnastic
exercises targeting the
trunk muscles
Multimodal
back exercise
Guided, machine-
aided trunk muscle
exercises
Endurance
Swimming, running,
(nordic) walking,
biking, hiking,
crosscountry, inline
skating, various
Gymnastics
Types: general
gymnastics,
aqua, ski, senior,
involution,
functional; pilates
Fitness
Aerobics, jazz
dance, (aqua) tness
training, tness
center
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2020 EDIZIONI MINERVA MEDICA
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one le and print only one copy of this Article. It is not permitted to make additional copies (either sporadically
or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet le sharing systems, electronic mailing or any other means which may allow access
to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove,
cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher.
MÜLLER IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN
588 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE October 2020
For comparative purposes, the original scoring method is
presented in Table I. Moreover, the values of specic pain
items, functional items, employment status and sick days
are included in Table I.
Across the study period, participants spent an average
of 3193 minutes per 6-month period (123 minutes per
week, SD=147) on exercises at a medium level of sub-
jective perceived physical exertion (M=5.22; SD=1.97).
Most of the total hours were spent on endurance training
(67%), while moderate gymnastic exercises accounted for
only 2% of the total exercise volume across participants
(Table II).
Health effects
The relative effectiveness of different exercise patterns in
reducing BPFS was examined in a two-level HLM with
repeatedly over time, HLMs also known as linear mixed
models or multilevel models, are applied. They are an ex-
tension of linear regression, which is more exible in sev-
eral aspects. Unlike in the case of linear regression model,
which requires independent observations, HLMs allow
dependent residuals and allows the modeling of the co-
variance structure of the data. While in repeated measure-
ments ANCOVAs, another model to analyze longitudinal
data, only participants, who are observed at all occasions,
can be included in the model and participants with even a
single missing value are discarded or their missing values
have to be imputed, in HLMs one or more of the occasions
for measurement may be missing for participants and there
is no need to impute missing values. HLMs are the method
of choice for longitudinal studies,35 allowing the inclusion
of cases with missing data. The nested data structure of
the longitudinal data is addressed in two-level models, in
which the repeated measures are viewed as a level (level 1)
nested within the participants (level 2). Back pain (BPFS)
and direct medical costs of back disorders were modelled
as dependent variables. Participant characteristics and ex-
ercise patterns were included as independent variables:
sex, age (centered), BPFS (t0), type of exercise, subjective
perceived physical exertion (centered) and exercise vol-
ume for each assessment period (cumulated hours within
a 6-month period). As the study is designed as an observa-
tional study, the participants reported within the question-
naire their individually performed exercise patterns and it
can vary from measurement to measurement. They were
not assigned to a specic exercise pattern. There are no
groups dened by type of exercise (endurance exercise,
etc.). The HLMs allow to estimate the effect of the amount
of exercise patterns in the 5 categories on BPFS and medi-
cal costs, corrected for baseline measurements and demo-
graphic characteristics. We set the α-level at P≤0.05. The
statistical analyses were performed with IBM SPSS 24.
Results
In total, 2542 participants (66% females) were included
in the analyses. Most participants had a middle level of
education (80.5%), and their ages spanned a range of 17
to 83 years (Mean [M], Standard Deviation [SD], M=46.9;
SD = 12.3) (Table I). Mean direct medical costs in the
six months preceding enrolment in the study was 204 €
(SD=893 €). At baseline, average back pain ratings on the
chronic pain grade questionnaire were M=5.0 (SD=2.0) for
intensity and M=3.4 (SD=2.3) for impairment of function-
ing, corresponding to a BPFS score of M=4.2 (SD=2.0).
Table I.— Sample characteristics at baseline.
Age/sex
Age (M [SD]) 46.9 (12.3)
Females (%) 66
Employment status (%)
Employed 69.9
Pensioners 15.9
Unemployed 4.1
Family members without employment 10.1
Sick days past 12 mths
Dorsopathies (M [SD]) 6.9 (24.3)
Overall (M [SD]) 18.3 (45.1)
Education (%)
Lower secondary (10 yrs.) 17.3
Upper secondary (13 yrs.) 63.2
Postsecondary (13+ yrs.) 4.4
Tertiary (13+yrs.) 6.4
Back pain (Chronic Pain Grade Questionnaire)
Pain intensity (0-10) (M [SD]) 5(2)
Pain right now 3.9 (2.4)
Pain as bad as could be 6.4 (2.4)
Average pain 4.6 (2.2)
Impairment of functioning (0-10) (M [SD]) 3.4 (2.3)
Daily activities 3.4 (2.4)
Recreational, social and family activities 3.4 (2.5)
Work (including housework) 3.5 (2.5)
BPFS (0-10) (M [SD]) 4.2 (2)
Days in pain past 6 months (M [SD]) 76.1 (64.5)
Days with pain-related disability past 6 mths (M [SD]) 17.9 (37.4)
GCPS 1 (%) 40.5
GCPS 2 (%) 27.3
GCPS 3 (%) 20.7
GCPS 4 (%) 11.5
M= Mean, SD= Standard deviation
Graded chronic pain status 1= low pain intensity
Graded chronic pain status 2= high pain intensity
Graded chronic pain status 3= moderate functional impairment
Graded chronic pain status 4= severe functional impairment
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IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN MÜLLER
Vol. 56 - No. 5 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE 589
level of initial pain by one point on the BPFS (rating scale
0-10) augmented the pain-reducing effect of moderate- to
high-intensity exercises and exacerbated the disadvantage
of exercising at high physical exertion levels by a factor of
0.8 (Figure 3). The effect of age was less pronounced than
the effect of initial back pain, lowering the pain-reducing
effects for older participants by 0.1 points/BPFS per 10
years in age difference (Table III).
Economic effects
In the two-level HLM on economic effects, only MMBE
was signicantly associated with a cost reduction
(ßMMBE=-1.72, t=-3.6, P=<0.001). The effect of cost re-
duction through MMBE increased slightly with the level
of back pain (ßBPFS t0*MMBE=-0.66, t=-2.7, P=0.008) (Ta-
ble IV). Thus, an average exercise volume reduced medi-
cal costs by 86 € (ßMMBE* 50 hrs), which is a reduction
of 42% compared to the baseline costs (mt0 =204 €). Ini-
tial back pain and sex signicantly moderated this effect.
initial back pain, age and sex as control variables (Table
III). Overall, the model explained 32% of the variance in
self-reported pain (BPFS).
Only exercise categories requiring moderate to high
levels of intensity/muscular load yielded signicant pain-
reducing effects (i.e. ßMMBE=-0.029, t=-30.0, P<0.001; ßt-
ness=-0.002, t=-5.1, P<0.001) (Table III). The effect was
stronger for MMBE than for tness by a factor of 14.5
(βMMBE/βtness). In other words, an average participant ex-
ercising approximately 2 hrs per week for half a year (50
hrs) would experience a pain reduction of 1.43 points in the
BPFS (βMMBE* 50 hrs) with MMBE and a pain reduction
of 0.1 points with tness exercises (βtness* 50 hrs). Ex-
ercising at higher levels of subjective perceived exertion
signicantly increased back pain (ßexertion=0.08, t=8.23,
P<0.001). Given the average degree of exertion (M=5.22;
SD=1.97), an increase/decrease by one standard deviation
would be associated with an increase/decrease in back
pain of 0.16 points in the BPFS (SDexertion* ßexertion). The
effects of MMBE, tness and physical exertion increased
with the level of initial back pain (Table III).
Among the participant baseline characteristics, initial
back pain and the age of the participants signicantly
moderated the effects of the exercise patterns. A higher
Figure 3.—Effectiveness for the upper and lower tertiles of subjective
perceived physical exertion. aLeft-hand side: participants with high ini-
tial back pain (BPFSt0>5.2); btertiles of subjective perceived physical
exertion; low: ≤4.6, 4.6< medium ≤6.0, high >6.0; cright-hand side: par-
ticipants with low initial back pain (BPFSt0<3.3).
Table II.— Exercise volume per category and 6-month period.
Category Time total (minutes) SD %
Endurance 2,131 3,024 67
Fitness 419 1,067 13
Back gymnastics 328 695 10
Multimodal back exercise 247 307 8
Gymnastics 69 236 2
Total 3,193 3,831 100
Table III.— Results from the hierarchical linear model for BPFS.
ß-coefcient SE t-value PCondence interval 95%
Lower bound Upper bound
Constant term 3.91803 0.03469 112.946 <0.001 3.85002 3.98605
Age 0.01065 0.00202 5.261 <0.001 0.00668 0.01462
Sex (male=1) -0.00003 0.05133 -0.001 0.999 -0.10069 0.10062
Physical exertion 0.07985 0.00970 8.231 <0.001 0.06083 0.09887
Multimodal back exercise -0.02866 0.00095 -30.047 <0.001 -0.03053 -0.02679
Endurance -0.00025 0.00014 -1.877 0.061 -0.00052 0.00001
Fitness -0.00197 0.00039 -5.109 <0.001 -0.00273 -0.00122
Gymnastics -0.00058 0.00146 -0.398 0.691 -0.00343 0.00227
Back gymnastics 0.00065 0.00062 1.048 0.295 -0.00057 0.00187
BPFS t0 0.83987 0.01425 58.934 <0.001 0.81193 0.86781
BPFS t0*physical exertion 0.02631 0.00465 5.661 <0.001 0.01720 0.03542
BPFS t0*MMBE -0.00918 0.00050 -18.422 <0.001 -0.01016 -0.00820
BPFS t0*tness -0.00058 0.00016 -3.631 <0.001 -0.00089 -0.00026
7
6
5
4
3
2
1
0
Back pain function score
High initial back pain (BPFS)a
T0 T1 T2 T3 T4
± 1 SE
7
6
5
4
3
2
1
0
Back pain function score
Physicalb
exertion
low
medium
high
...
T0 T1 T2 T3 T4
± 1 SE
Low initial back pain (BPFS)c
COPYRIGHT
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2020 EDIZIONI MINERVA MEDICA
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one le and print only one copy of this Article. It is not permitted to make additional copies (either sporadically
or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet le sharing systems, electronic mailing or any other means which may allow access
to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove,
cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher.
MÜLLER IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN
590 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE October 2020
sectional enlargement).40 Strengthening the spine-stabilizing
musculature may thus counteract any disturbances in muscle
activation patterns, weakness and fatigability inducing and/
or resulting from the experience of back pain.12, 41-44
An unexpected nding was that although exercising
at a higher intensity was more effective, higher subjec-
tive perceived physical exertion levels during the exercise
sessions intensied back pain. This ostensible contradic-
tion might be explained by a combination of physiologi-
cal and psychological effects. The physiological overload
aligned with maximum exertion not only harbors the risk
of damage but also leads to sensations that might be per-
ceived as gratifying in the context of strength training but
often fuel the fear of pain in rehabilitation patients.45 In
implementing an exercise regimen for preventive or clini-
cal purposes, the general aim should be attaining optimal
rather than maximum results.46 For individuals with back
pain in particular, the experience of painless physical ac-
tivity is assumed to positively change beliefs, attitudes,
and coping mechanisms.47-49 In addition, exercising with
high levels of intensity might enable the feeling of having
mastered a challenge and thus reduce avoidance behav-
iors in the future. However, not only fear avoidance beliefs
lead to physical inactivity. There are further internal and
external barriers for physical activity. The most common
internal barriers for middle-aged people were “too tired,”
“already active enough,” “do not know how to do it” and
“too lazy,” while those for elderly people were “too tired,”
“lack of motivation” and “already active enough”.50 How-
ever, compared to the fear avoidance beliefs these barriers
might be of minor relevance for back pain patients.
In the cost-efcient analysis of our data, only the
MMBE program yielded a signicant reduction in direct
medical costs for back disorders. On the other hand, tness
Cost reduction was more pronounced in male participants
than in female participants (ßsex=71.6, t= 3.3, P=0.001)
and in those with higher levels of initial back pain than
those with lower levels of initial back pain (ßBPFSt0= 58.2,
t=8.9, P<0.001). Overall, the model explained 33% of the
variance in direct medical costs.
Discussion
The present study examined how intensity, specicity, and
subjective perceived physical exertion inuence the effects
of exercise on pain reduction and medical costs in adults
with back pain, based on data from a 24-month observa-
tional cohort study with a large, heterogeneous communi-
ty sample. The results indicate that only exercise patterns
with a moderate to high intensity in terms of muscular load
signicantly reduced pain, i.e. tness training and MMBE,
whereas exercise patterns requiring less muscular effort,
such as endurance training, gymnastics and back gymnas-
tics, did not yield signicant effects. The effectiveness of
exercises with moderate to high intensities was multiplied
by a factor of 14.5 when the spine-stabilizing muscula-
ture was targeted. Only this combination of intensity and
specicity, as applied in the MMBE program, signicantly
reduced direct medical costs for back disorders. The analy-
ses were controlled for sex, age and initial back pain.
These results add to the empirical evidence that a minimum
threshold of exercise intensity must be exceeded to reduce
back pain effectively.12, 36-39 From a physiological perspec-
tive, the relative advantage of specic training is a logical
consequence of this effect; exercises of high intensity elicit
large muscle activations, which in turn stimulate the neural
and physiological adaptations associated with improved
functionality and strength of the targeted musculature (cross-
Table IV.— Results from the hierarchical linear model for direct medical costs for back disorders.
ß-coefcient SE t-value P Condence interval 95%
Lower bound Upper bound
Constant term 161.10 16.19 9.949 <0.001 129.35 192.85
Age 0.29 0.86 0.331 0.741 -1.41 1.98
Sex (male=1) 71.64 21.73 3.297 0.001 29.02 114.25
Physical exertion -7.71 4.92 -1.565 0.118 -17.36 1.95
Multimodal back exercise -1.72 0.48 -3.602 <0.001 -2.65 -0.78
Endurance -0.05 0.06 -0.839 0.402 -0.18 0.07
Fitness 0.03 0.18 0.186 0.852 -0.32 0.39
Gymnastics 0.35 0.67 0.521 0.602 -0.97 1.67
Back gymnastics -0.05 0.28 -0.159 0.873 -0.60 0.51
BPFS t0 58.24 6.54 8.903 <0.001 45.41 71.07
BPFS t0*physical exertion -2.29 2.35 -0.973 0.331 -6.90 2.32
BPFS t0*MMBE -0.66 0.25 -2.661 0.008 -0.60 0.51
BPFS t0*tness -0.09 0.07 -1.208 0.227 -0.60 0.51
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IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN MÜLLER
Vol. 56 - No. 5 EUROPEAN JOURNAL OF PHYSICAL AND REHABILITATION MEDICINE 591
physical exertion and objective physical load (i.e. inten-
sity of exercise) is assumed.21 However, this relationship
has been shown to be inuenced by psychological, social
and contextual factors, all of which might inuence the
perception of physical exertion in individuals with chron-
ic back pain.53, 54 Interestingly, in a parallel analysis of
the data presented in this article, the number of training
sessions was more relevant for back pain reduction than
were increases in physical performance.32 A more com-
prehensive understanding of the complex interaction be-
tween physiological and psychological mechanisms may
be valuable in improving exercise interventions for back
pain. For example, it may be conceivable to give correc-
tive feedback and/or adjust exercises based on combined
information about subjective perceived physical exertion
and objective load, thus increasing the effectiveness of
exercises.
Conclusions
In conclusion, this study indicates that a certain intensity
of exercise is an essential prerequisite for back pain reduc-
tion, which is most effectively achieved when the spine-
stabilizing musculature is targeted and the level of subjec-
tive perceived physical exertion is not exceedingly high.
The intensities in terms of muscular load in endurance
training and gymnastics may not be sufcient to reduce
back pain effectively. Only the combination of high-in-
tensity and high-specicity exercises yielded a signicant
reduction in medical costs. More research is needed to dis-
entangle the physiological and psychological mechanisms
of action involved in these differential effects of exercise
patterns.
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2020 EDIZIONI MINERVA MEDICA
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or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet le sharing systems, electronic mailing or any other means which may allow access
to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove,
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or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet le sharing systems, electronic mailing or any other means which may allow access
to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove,
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IMPORTANCE OF EXERCISE IN REDUCING BACK PAIN MÜLLER
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Conicts of interest.—The authors certify that there is no conict of interest with any nancial organization regarding the material discussed in the manuscript.
Authors’ contributions.—All authors read and approved the nal version of the manuscript.
History.—Article rst published online: June 4, 2020. - Manuscript accepted: June 3, 2020. - Manuscript revised: May 29, 2020. - Manuscript received:
August 23, 2019.
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