Content uploaded by Juan M. Cortell-Tormo
Author content
All content in this area was uploaded by Juan M. Cortell-Tormo on Oct 12, 2017
Content may be subject to copyright.
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 1
Journal of Back and Musculoskeletal Rehabilitation -1 (2017) 1–11 1
DOI 10.3233/BMR-169684
IOS Press
Effects of functional resistance training on
fitness and quality of Life in females with
chronic nonspecific low-back pain
Juan M. Cortell-Tormoa,∗, Pablo Tercedor Sánchezb, Ivan Chulvi-Medranoa, Juan Tortosa-Martíneza,
Carmen Manchado-Lópeza, Salvador Llana-Bellochcand Pedro Pérez-Sorianoc
aDepartment of General and Specific Didactics, Faculty of Education, University of Alicante, Alicante, Spain
bFaculty of Physical Activity and Sports Sciences, University of Granada, Granada, Spain
cFaculty of Physical Education and Sports, University of Valencia, Valencia, Spain
Abstract.
BACKGROUND: Exercise is important as adjuvant in the chronic low back pain (CLBP) treatment. Functional training could
involve benefits for low back pain (LBP) patients.
OBJECTIVE: To evaluate the effects of a 12-week period of functional resistance training on health-related quality of life
(HRQOL), disability, body pain, and physical fitness in CLBP females.
METHODS: Nineteen females CLBP were recruited according to Paris Task Force on Back Pain criteria. Participants were
randomly assigned to an exercise group (EG); and a control group (CG). Subjects were tested at baseline and at week 12 after 24
sessions, 2 days per week. Body pain was assessed using visual analog scale (VAS), disability with Oswestry Disability Index
(ODI) and HRQOL with Short Form 36 questionnaire. Physical fitness was measured using: flamingo test, back endurance test,
side bridge test, abdominal curl-up tests, and 60-s squat test.
RESULTS: EG showed significant improvements in physical function (10%; p < 0.05), body pain (42%; p < 0.05), vitality
(31%; p < 0.05), physical component scale (15%; p < 0.05), VAS (62.5%; p < 0.01), ODI (61.3%; p < 0.05), balance (58%;
p < 0.05), curl-up (83%; p < 0.01), squat (22%; p < 0.01), static back (67%; p < 0.01), and side bridge (56%; p < 0.01).
CONCLUSION: Periodized functional resistance training decreased pain and disability and improved HRQOL, balance and
physical fitness in females with CLBP, and can thus be used safely in this population.
Keywords: Resistance training, disability, therapy, pain, exercise, women
1. Introduction1
Low back pain is related to disability and work ab-2
sence and accounts for high economical costs [1]. In3
the majority of cases of CLBP the etiology is not clear,4
and the term “nonspecific” is thus used [2]. One pos-5
∗Corresponding author: Juan M. Cortell-Tormo, Department of
General and Specific Didactics, Faculty of Education, University of
Alicante, Campus de Sant Vicent del Raspeig, s/n, 03690, Sant Vi-
cent del Raspeig, Alicante, Spain. Tel.: +34 965909676; Fax: +34
965903721; E-mail: jm.cortell@ua.es.
sible factor in the genesis and persistence of CLBP is 6
mobility, stability and control of the lumbopelvic re- 7
gion [2]. Exercise rehabilitation programs commonly 8
used for patients with CLBP are based on strengthen- 9
ing exercises or trunk stabilization [3]. In one hand, tra- 10
ditional core exercises (TCE) usually include relatively 11
high-intensity exercises that activate both the flexors 12
and extensors of the trunk, superficial muscles of the 13
Global Stabilizing System (GSS) (e.g. back extension 14
or sit up) [4,5]. On the other hand, core stability exer- 15
cises (CSE) aim to activate deep core muscles of the 16
Local Stabilizing Sytem (LSS) (e.g. prone plank, side 17
ISSN 1053-8127/17/$35.00 c
2017 – IOS Press and the authors. All rights reserved
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 2
2J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain
bridge). Both, TCE and CSE, have been shown effec-18
tive for decreasing pain [6–9] and disability [8–11],19
as well as for improving health-related quality of life20
(HRQOL) [8,12–14]. This could be explained by the21
fact that dysfunction of movement around a joint can22
be a local or a global problem, although both fre-23
quently occur together [4]. A recent systematic review24
reported that exercise contributes to the treatment of25
chronic pain, but highlights that it is still not clear ex-26
actly which factors or particular types of exercises may27
be attributed to such improvements [15].28
Efficient movement function and the maintenance of29
balance during dynamic tasks are more complex than30
merely adequate force production from the muscles. It31
requires sensory, biomechanical and motor-processing32
strategies along with learned responses from previous33
experience and anticipation of change [16]. Spinal pro-34
prioception and balance have been found to be abnor-35
mal in patients with chronic low back pain [17,18].36
In parallel, Trunk balance deficits and muscle impair-37
ments could also originate from poor position sense,38
which has been reported to be present in individuals39
with CLBP [19].40
Exerting external forces while attempting to main-41
tain dynamic balance forms the base of success for per-42
forming efficiently and safely activities of daily liv-43
ing [20]. Patients with CLBP have difficulty main-44
taining balance, especially under challenging condi-45
tions [21]. Stabilization of the trunk is crucial for main-46
taining static or dynamic balance, especially to provide47
a solid base when attempting to exert forces upon ex-48
ternal objects [20]. Patients with chronic low back pain49
have poorer postural control of the lumbar spine than50
healthy control subjects and this difference increases51
with increasing task difficulty level [22]. Thus, the goal52
of core stability exercise programs is enabling perfor-53
mance of high-level activities in daily life and sports,54
while keeping the spine stabilized [23].55
TCE and CSE involve a limited motor challenge.56
These exercises should be used in the early stages of57
intervention in CLBP patients, but if the aim is to make58
more functional exercises that involve a continuum in59
the motor problem, we must train specific movements60
with asymmetrical loads, involving multiple joints and61
planes of motion at the same time (multi-joint and mul-62
tiplanar) that correspond more closely to how humans63
interact with their environment [24].64
Functional Resistance Training (FRT) involves mul-65
tiplanar and multijoint resistance exercises that simu-66
late movement patterns from everyday life and sport.67
Functional training exercises tend to focus more on the68
coordination, technique, posture, and core engagement 69
instead of on training loads. The goal of FRT is not hy- 70
pertrophy but to promote a potential motor problem in 71
order to train dynamic stabilization. Appropriate func- 72
tional exercises are those in which the lumbo-pelvic 73
region remains aligned within the neutral zone by co- 74
contraction of the muscles of the trunk, while other 75
demands executed with the extremities are simultane- 76
ously and successfully fulfilled [25]. This method of 77
training usually includes: a) spinal stabilization exer- 78
cises; b) balance and proprioceptive exercises; c) flex- 79
ibility exercises; d) resistance training exercises [26]. 80
Motor improvements obtained by functional training 81
have been attributed to the mechanical principle of 82
specificity [27]. 83
Poor movement patterns can lead to back disor- 84
ders [28]. Control of quality of movement patterns in 85
FRT is more challenging than in other types of exer- 86
cise, and could thus represent a good strategy for treat- 87
ing CLBP. However, the effects of FRT in subjects with 88
CLBP are not currently known. Therefore, the aim of 89
the present study was to evaluate the effects of func- 90
tional resistance training on HRQOL, pain, disability 91
and physical fitness related to daily activities in women 92
with CLBP. 93
2. Methods 94
2.1. Subjects 95
Twenty-four women from an Outpatient Physiother- 96
apy Clinic in Spain volunteered to participate in this 97
study. During the selection procedure, a physician re- 98
viewed their medical records and clinical status and 99
confirmed the diagnosis according to Paris Task Force 100
on Back Pain criteria [29]. Subjects received an orien- 101
tation to study procedures and were informed of the ex- 102
perimental risks. All subjects signed an informed con- 103
sent document before the investigation. The investiga- 104
tion was approved by the University of Alicante Re- 105
search Ethics Board for the Use of Human Subjects. 106
The inclusion criteria were: 1-women between 20 and 107
55 years of age; 2-women with low back pain as a pri- 108
mary complaint, without associated leg pain; 3-women 109
suffering from chronic (>3 months, >3 d·wk−1) non- 110
specific (soft tissue in origin) low-back (lumbar 5 to 111
lumbar 1) pain; and 4-no history of formal exercise 112
training. Subjects were excluded if they: 1-were receiv- 113
ing concurrent treatments from another practitioner for 114
their low back pain; 2-were diagnosed as having a tu- 115
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 3
J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain 3
Table 1
Characteristics of females with low-back pain at baseline
Exercise Control
group group
(N=11) (N=8) P
Age (yr) 35.6 ±7.9 35.6 ±9.7 0.934
Duration of symptoms 19 ±6.3 20.4 ±5.6 0.628
(months)
Weight (kg) 61.3 ±9.9 65.4 ±5.8 0.302
Height (cm) 163.2 ±8.9 164.2 ±5.9 0.200
Body mass index 23.8 ±2.3 24.3 ±2.4 0.619
(kg·m−2)
Waist-hip ratio 0.7 ±0.04 0.7 ±0.05 1.000
Muscular mass (kg) 20.7 ±2.7 21.9 ±1.7 0.137
Fat mass (kg) 22.6 ±3.3 24.5 ±3 0.248
Values expressed as mean ±standard deviation.
mor, infection, or inflammatory disease affecting the116
spine; 3-had spinal or lower-limb surgery; 4-had spinal117
fractures or structural deformities such as spondy-118
lolisthesis and spondylolysis; 5-had any contraindi-119
cations to exercise therapy (e.g., uncontrolled hyper-120
tension, previous myocardial infarction, cerebrovas-121
cular disease, peripheral vascular disease, respiratory122
disorders); 6-were involved in workers’ compensation123
claims; 7-had signs of nerve root compromise, defined124
as decreased tendon reflexes, sensory loss, and motor125
deficits; and 8-were receiving medications other than126
analgesics and nonsteroidal anti-inflammatory drugs.127
The subjects were randomly assigned to either an ex-128
ercise group (EG) or a control group (CG) using a ran-129
domized number sheet. The EG and CG presented sim-130
ilar characteristics at baseline (Table 1).131
Initially, 24 subjects took part in the study and 19132
completed the 12-week follow-up (EG n=11; CG133
n=8) (Fig. 1).134
Each subject performed all the tests and question-135
naires in two sessions and the sequence of application136
was the same at baseline and after 12 weeks. First, the137
diagnosis of CLBP was verified, then the HRQOL, the138
visual analog scale (VAS) and the Oswestry Disability139
Index (ODI) were administrated. The second day, the140
fitness test battery was applied.141
2.2. Procedures142
Subjects completed health surveys at baseline and143
week 12. These included the visual analog scale (VAS)144
for the degree of back pain felt by the subject during a145
typical week, the Oswestry Disability Index (ODI), and146
the Short-Form 36 Health Survey (SF-36). The VAS147
is a simple visual scale used to measure pain intensity148
(0 =no pain; 10 =maximal pain) [30]. The ODI is149
a disease-specific outcome measure used in the man-150
agement of spinal disorders (0 =no disability; 100 151
=maximum disability) [31]. The Spanish version of 152
the SF-36 [32] was used to evaluate HRQOL. The SF- 153
36 assesses eight dimensions: physical function, role 154
physical problems, body pain, general health percep- 155
tion, vitality, social function, role emotional problems, 156
and mental health. The scale of each dimension runs 157
from ‘0 =very poor’ to ‘100 =very good’. 158
2.3. Anthropometric measures 159
To evaluate height (cm) a stadiometer (SECA, model 160
225, Germany) with a range scale of 0.10 cm was used 161
and body mass (kg) was measured to the nearest 0.1 kg 162
using a digital scale (Philips, type HF 351/00). These 163
parameters were assessed prior to any physical perfor- 164
mance test. Body mass index (kg·m−2) was calculated. 165
Waist-Hip ratio (WHR) was consequently calculated 166
as the ratio of waist circumference over the hip cir- 167
cumference. The anthropometric measures taken were 168
8 skinfolds by the same investigator (ISAK). Muscle 169
mass was calculated using the Lee equation [33]. Fat 170
mass was calculated using the Withers equation [34]. 171
2.4. Physical fitness 172
First, postural balance was assessed with a blind 173
flamingo test [44], in which the barefoot subject stood 174
on one leg while the other leg was flexed at the knee 175
and the ankle was held by the hand of the same side 176
of the body, performed with closed eyes. The number 177
of trials that the subject needed to complete 30 s of 178
the static position was measured. The outcome was ex- 179
pressed as the number of trials (equal to the number of 180
falls +1). The test-retest intraobserver reliability coef- 181
ficient was r=0.92. 182
Then, the static back endurance test (intraclass co- 183
efficient =0.88) was performed with the subject ly- 184
ing prone on a flat bench, with the ankles anchored un- 185
derneath a pad. The tip of the iliac crest rested on the 186
edge of the bench and the arms were folded across the 187
chest. Once the subject was lying down with a hori- 188
zontal position, the stopwatch was started. When the 189
subject was no longer able to maintain the starting po- 190
sition, the watch was stopped. For the side bridge test 191
(intraclass coefficient =0.90), the subject was asked 192
to determine the preferred side for the test. This was in 193
accordance with previous studies where subjects were 194
able to self-select which side would be measured [35]. 195
The starting position involved the subject lying side- 196
ways on the floor while propped up on the feet and the 197
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 4
4J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain
Fig. 1. Diagram of the study, total number of subjects and number of dropouts.
forearm closest to the ground. The legs were extended.198
The subject lifted the body up off the floor and held199
this position for as long as possible while supporting200
the body weight. The stopwatch was started when the201
subject assumed the correct position and was stopped202
when it was no longer maintained [36].203
Immediately afterward, the abdominal curl-up tests204
measured the muscular endurance of the abdominal205
muscles (intraclass coefficient =0.87). The test was206
terminated when the subject was unable to maintain the207
required cadence or unable to maintain the proper curl-208
up technique for 2 consecutive repetitions despite re-209
ceiving feedback from the researcher. A maximum of210
3 corrections were allowed by the evaluator before ter-211
mination of the test. The subject was positioned supine212
with the head resting on the mat, arms straight at sides213
and parallel to the trunk, palms of hands in contact with214
the mat, and the middle finger tip of both hands at the215
0 mark (identified by a piece of tape). Knees were bent216
at 90◦and the heels kept contact with the mat. The test217
was performed with shoes on and cadence was set by a218
metronome (50 bpm). The test started with a slow curl-219
ing up of the upper spine far enough so that the middle 220
finger tips of both hands reached the 8-cm mark iden- 221
tified by tape. Each subject completed as many repeti- 222
tions as possible. 223
Finally, the 60-s squat test (intraclass coefficient =224
0.81) was chosen as a measure of lower body muscle 225
endurance. It was performed third, and for the greatest 226
possible number of repetitions in 1 min with a thigh 227
position parallel to the floor at the bottom of the range 228
of movement and without carrying out assisted move- 229
ments using other body segments [37]. 230
To assess test-retest reliability, intraclass correla- 231
tions (ICCs) comparing baseline with week 12 were 232
performed using the CG data. The following dependent 233
variables were analyzed: postural balance, abdominal 234
crunch, 60-s squat, static back, side bridge, PCS, and 235
MCS. 236
2.5. Exercise therapy 237
The EG exercised in Physiotherapy Clinic, two 238
times per week for a 12-week period. The EG was di- 239
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 5
J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain 5
Stage 1 Exercises
The aim of the first stage is to train the specific isometric co-contraction of
transversus abdominis with lumbar multifidus at low levels of maximal voluntary
contraction and with controlled respiration, in weight bearing within a neutral
lordosis [52].
4-point kneeling and lying positions Lying (controlled
leg movement). Lying on back. Sitting and standing
positions.
Stage 2 Exercises
The second phase is the associative stage, where the focus is on refining a par-
ticular movement pattern in analytic and isometric resistance training.
Abdominal crunch. Back extension. Side plank. El-
bow bridge. Squat. Lunges. Seat pull and row.
Stage 3
The third stage is the aim of the specific exercise intervention, whereby sub-
jects can dynamically stabilize their spines appropriately during exercises like a
functional demands of daily living.
Single leg Deadlift. Anterior Reach. Lunges. Stand
row. Pull squat. Stand push.
Applications Exercises
Single leg Deadlift Anterior Reach
Lunges Stand row
Pull squat Stand push
Fig. 2. Exercise program.
vided in three subgroups (two groups of 4 and one of240
3 subjects). Each subgroup was monitored by the same241
specialist (qualified personnel), who led each train-242
ing session. At least one trained monitor was always243
present to verify the correct application of the method-244
ology. Each therapy session ranged from 45 to 60 min245
depending on the phase. A warm-up of 6–7 min of246
mild cardiovascular exercise followed by 3–4 min of247
stretching was always performed prior to the training248
sessions. A cool-down of 1 min of mild cardiovascular249
exercise followed by 4 min of stretching was always250
performed after the training sessions.251
The subjects were instructed in the different exer-252
cise techniques and in controlling exercise intensity253
through the combined use of a targeted number of rep-254
etitions and perception of effort during two sessions255
before beginning the training program. The criteria of256
body position, ranges of motion and movement speed257
followed the guidelines described by O’Sullivan [38],258
Koumantakis et al. [39]; Carter et al. [36], McGill [40];259
and Santana [41].260
The load (resistance) for each exercise was deter- 261
mined according to the rating of perceived exertion 262
in active muscles by using the OMNI resistance ex- 263
ercise scale for active muscles. The maximum value 264
(10-extremely hard) indicates that the subject has per- 265
ceived that the set performed with a previously deter- 266
mined number of repetitions has been performed with a 267
maximal volitional effort, while the 0 value (extremely 268
easy) indicates no effort at all [42]. This enabled the 269
establishment of new loads for each exercise to contin- 270
ually stress the bodies of the EG throughout the study. 271
The load was readjusted when the subject was unable 272
to maintain the required intensity or unable to main- 273
tain the proper technique (co-contraction while main- 274
taining a neutral lordosis) for 2 consecutive repetitions 275
despite feedback from the researcher. 276
The stabilizing exercises were taught by asking the 277
patients to draw in the stomach while giving them 278
verbal, visual, and tactile feedback and measuring 279
the pressure change with a biofeedback meter [10]. 280
The control of neutral lordosis for seat pull and row 281
exercises was determined with the pressure changes 282
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 6
6J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain
Fig. 3. Periodization of training.
on biofeedback meter. The EG performed upper- and283
lower-body resistance training exercises that consisted284
of free weights (dumbbell), gym apparatus and body285
weight (Fig. 2).286
The resistance machine used was the Life Fitness287
Dual Adjustable Pulley (Life FitnessTM), which al-288
lowed for full range of motion, smooth action, and easy289
pin adjustment of the load. From seventeen to twenty290
sessions symmetric and asymmetric loads were com-291
bined. First set symmetric, second and third asymmet-292
ric (changing high load for side). The last five ses-293
sions in stand row and stand push exercises asymmet-294
ric loads were applied. In each set, half of repetitions295
were performed with a higher load in the non-dominant296
hand (from the 20th to the 24th sessions, the differ-297
ence between the loads progressed from 10 to 30%)298
and the other half with a higher load in the dominant299
hand. During the entire 12-wk period, participants in300
the CG continued their daily activities, which did not301
include any form of physical exercise similar to those302
in the therapy. The number of sets, repetitions, resting303
period between sets and exercises and the desired per-304
ception of effort for the sets were the same for three 305
subgroups during the 12 weeks of training (Fig. 3). 306
2.6. Statistical analysis 307
All values are reported as mean ±SD. Age, height, 308
body mass, body fat, abdominal curl-up, 60-s squat, 309
side bridge, static back endurance, postural balance, 310
VAS, ODI, and SF-36 PCS and MCS were analyzed 311
via a general linear model with repeated-measures 312
analysis of variance (ANOVA), to compare the CG and 313
EG groups from baseline to week 12. Data distribu- 314
tion was checked by the Shapiro-Wilk test. For nor- 315
mally distributed variables, the Levene test for homo- 316
geneity of variances was completed on each dependent 317
variable during the ANOVA. When the data were not 318
normally distributed, the Friedman ANOVA followed 319
by the Wilcoxon signed-rank test was used. When a 320
significant F ratio was achieved, post hoc comparisons 321
were completed using a Fisher least significant differ- 322
ence. For all tests, the significance level was set at p323
<0.05. The corrected effect size was estimated with 324
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 7
J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain 7
Table 2
Health-related quality of life at baseline and after 12-wk of training (exercise group, N=11; control group, N=8)
Baseline Week 12
Exercise Control Exercise Control Training effect
M±SD M ±SD M ±SD M ±SD M (95% CI) ES P
VAS (0–10) 4 ±1.8 4.5 ±1.6 1.5 ±1.5 4.4 ±1.4 2.5 (3.9 to 1.1) 1.45 0.001
ODI (0–100) 15.5 ±8.4 14 ±12 6 ±6.1 14.5 ±11.1 9.5 (17.5 to 1.4) 1.24 0.023
SF-36 (0–100)
Physical function 83.2 ±12.1 86.3 ±12.5 91.8 ±6.4 84.4 ±9 8.6 (17.5 to 0.2) 0.85 0.048
Role physical 63.6 ±43.8 71.9 ±41.1 86.4 ±25.9 75 ±40 22.7 (55.6 to 10.2) 0.60 0.169
Body pain 52.8 ±27.3 53.2 ±10.1 75.1 ±24.9 65.5 ±22.4 21.9 (40.7 to 3.1) 0.82 0.024
General health 63.9 ±13.5 66.5 ±30.9 73.4 ±13.9 65.9 ±30.7 9.5 (28.9 to 10) 0.66 0.329*
Vitality 52.7 ±13.7 54.4 ±17.2 68.9 ±16.3 71.9 ±13.9 15.5 (28.7 to 2.2) 1.03 0.024
Social function 70.5 ±28.7 70.3 ±32.7 89.8 ±13.5 87.5 ±17.7 19.3 (40.2 to 1.5) 0.82 0.068
Role emotional 69.7 ±43.3 70.8 ±37.5 69.7 ±45.8 75 ±46.3 0 (37.8 to 37.8) 0.00 1.000*
Mental health 62.5 ±15.5 66.5 ±22.1 73.5 ±14.9 72.5 ±17.9 10.9 (26 to 4.1) 0.82 0.151*
Component scale (SF-36) 0.00
Physical component scale 46.4 ±7.7 47.5 ±9.4 53.2 ±6.8 48.4 ±7.3 6.9 (13.6 to 0.2) 0.82 0.045
Mental component scale 42.5 ±13.9 43.2 ±11.4 46.2 ±11.8 48.8 ±10.6 3.7 (14.2 to 6.9) 0.00 0.483*
Values expressed as mean (M) ±SD, 95% CI and Effect Size (ES). VAS, Visual Analog Scale. ODI, Oswestry Disability Index. SF-36, Short
Form 36 Health Survey Pvalues of analysis of variance for repeated measures from baseline to week 12. *Non-parametric statistics.
Table 3
Physical fitness outcomes at baseline and after 12 weeks of physical training (exercise group, N=11; control group, N=8)
Baseline Change to 12 Weeks
Exercise Control Exercise Control Training effect
M±SD M ±SD M ±SD M ±SD M (95% CI) ES P
Balance (trials to 60 s) 8 ±5.8 11.8 ±9.9 3.4 ±3 11.1 ±9.3 7.8 (14.5 to 1.1) 0.95 0.024*
Curl-up (rep) 32.5 ±16.8 33.8 ±26.4 59.5 ±16.4 33.5 ±28.1 27 (45.8 to 8.3) 1.56 0.006*
Squat (rep) 39.5 ±9.5 39.1 ±6.1 48.2 ±1.7 35 ±15.6 13.2 (22.3 to 4) 1.22 0.006
Static back (s) 81.6 ±23.6 66.7 ±26.7 136 ±38.9 70.1 ±31.9 65.9 (95.3 to 36.6) 1.62 0.000
Side bridge (s) 47.4 ±29.8 35.1 ±20.9 74.1 ±27.8 27.7 ±20.4 46.4 (70.7 to 22.1) 0.89 0.000
Values expressed as mean (M) ±SD and the training effect 95% CI. Effect Size (ES). Pvalues of analysis of variance comparing differences
between groups at week 12; rep =number of repetitions performed; s =seconds. * Non-parametric statistics.
Hedges’ g[43]. The following scale was used to cate-325
gorize the magnitude of effect: <0.2 =trivial; 0.2–0.5326
=small; 0.5–0.8 =medium; 0.8–1.3 =large, and >327
1.3 =very large. All variables are reported as mean ±328
Standard Deviation (SD).329
3. Results330
Attendance to the therapy was controlled for every331
session. Only one participant from the EG dropped out332
because she changed her work place. Eleven patients333
in the EG attended more than 95% of the sessions, and334
8 patients in the CG fully completed the measurement335
protocol. Their results were included in the analysis.336
3.1. HRQOL, VAS, and ODI337
Baseline values showed no differences between the338
groups in any of the questionnaires (Table 2). After 339
12 weeks of exercise, a significant improvement at- 340
tributable to the treatment effects was found in physical 341
function (10%), body pain (42%), vitality (31%), phys- 342
ical component scale (15%), VAS (62.5%), and ODI 343
(61.3%), all in favor of EG. 344
3.2. Physical fitness 345
At baseline values in the physical tests for the EG 346
and the CG, no differences were observed (Table 3). 347
The EG showed significant improvements in balance 348
(58%), curl-up (83%), squat (22%), static back (67%), 349
and side bridge (56%) when compared with the CG/EG 350
at baseline (Table 3). 351
Figure 4 shows HRQOL at baseline (panel A) and 352
after 12 weeks of training (panel B) in comparison to 353
Spanish asymptomatic population [45]. 354
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 8
8J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain
CG =Control group. EG =Exercise group. RPOP =Reference popula-
tion [32]. PF =Physical function. RP =Role physical. BP =Body Pain. GH
=General health. V =vitality. SF =Social function. RE =Role emotional.
MH =Mental health. PCS =Physical component summary. MCS =Mental
component summary.
Fig. 4. Health-related quality of life at baseline (A) and after 12-wk
of training (B) in comparison to Spanish asymptomatic population.
4. Discussion355
This study sought to determine the effectiveness356
of functional resistance training as a rehabilitation357
strategy for individuals with CLBP. The methodology358
(1 and 2 stages) of the present study has been estab-359
lished to be suitable for studies which aim to detect360
changes in outcome measures of low back pain [38].361
The main contribution offered by this study is the in-362
clusion of a final stage which represents an increase in363
work intensity for the core area and in motor complex-364
ity for movement control. This is achieved from limit-365
ing the base of support, movement and asymmetries in366
the load.367
The present data support that the exercise pro-368
gram used is effective at inducing significant changes369
in physical fitness. The development of the muscu-370
loskeletal system produced by functional resistance371
training reduced pain and disability, recovering HRQOL
372
as well. Large improvements in muscular strength and373
balance were also reported within the EG. The baseline 374
values of the VAS, the ODI, and HRQOL were very 375
low among subjects in the present study. In the VAS, 376
a decrease of approximately two points (30%) has 377
been considered to be clinically important [46]. In the 378
present study, the change in VAS from baseline in the 379
EG was 62.5%. The improvement in pain symptoms 380
is somewhat higher than those obtained in other stud- 381
ies whose initial values were similar [47] or higher [7]. 382
Also improvement in pain symptoms is higher in sub- 383
jects who had higher initial values [48,49]. The find- 384
ings of the ODI were clinically important. The percent- 385
age decrease in the exercise group was 61.3%. These 386
results are consistent with other studies [9,50,51]. Be- 387
fore intervention, the subjects showed lower values in 388
HRQOL than reference values for the general Span- 389
ish population [45]. After 12 weeks of training, the ex- 390
perimental group showed FF, RF, SG, V, FS, SM and 391
PCS very similar to the reference population. In the DC 392
scale, there is also a marked improvement although it 393
does not match with the reference population. HRQOL 394
showed improvements similar to other studies [8]. 395
Previous CLBP exercise rehabilitation programs 396
used analytic exercises with low-moderate symmetric 397
loads focused on the core area [10,11,51,52] or high 398
loads [50] and whole-body workout [8]. Daily living 399
activities, either recreational or professional, could be 400
represented by global movements with limited stabil- 401
ity, asymmetric and with moderate-heavy load. Func- 402
tional training movements might be better for the de- 403
velopment of core strength and power due to the force, 404
velocity, and core stabilizing requirements that are 405
similar to the demands of daily living skills. People 406
with CLBP present motor control problems and/or de- 407
ficiencies that affect the ability to activate the muscles 408
responsible for stabilizing the spine [53]. Our study fo- 409
cused on progressively increasing the complexity and 410
intensity of the core area stability including exercises 411
of most muscle groups of the musculoskeletal system. 412
The aim of the first stage of this study was to train 413
the specific isometric co-contraction of transversus ab- 414
dominis with lumbar multifidus at low levels of maxi- 415
mal voluntary contraction and with controlled respira- 416
tion, in weight bearing within a neutral lordosis, main- 417
taining neutral zone. In the second stage, this was car- 418
ried out while maintaining the spine in a neutral lor- 419
dotic position and finally with normal spinal move- 420
ment. Segmental control and pain control must be 421
ensured at all times. This can be performed for sit 422
to stand, walking, lifting, bending, twisting, extend- 423
ing, etc. Subjects were encouraged to carry out regu- 424
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 9
J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain 9
lar resistance exercises while maintaining correct pos-425
tural alignment, low level local muscle system co-426
contraction and controlled respiration.427
Previous CLBP exercise rehabilitation programs428
have used a motor learning model in which the third429
stage subjects can dynamically stabilize their spines430
appropriately in an automatic manner during the func-431
tional demands of daily living [38]. However, these432
works did not apply controlled overload when subjects433
made the movements. This might be a potential error434
in the rehabilitation of CLBP because the movements435
can change after applying loads, which is important be-436
cause activities of daily living can be performed un-437
der external loads. The rationale for a global and asym-438
metric exercise regime was to mimic programs used by439
athletes that train specific skills, usually during a last440
phase of training. The same problem can be seen in441
several exercise rehabilitation programs [11,51,52]. In442
fact, most of them include, besides the therapy through443
exercises, educational and/or training therapies on pos-444
tural hygiene and ergonomics to improve motor skills445
and prevent relapse [10,51].446
In conclusion, many studies have examined the use447
of progressive overload exercise as a rehabilitative tool448
and have found mixed results. To date, most of the449
training programs have focused on analytic exercises450
and have used body weight and/or machine devices to451
add external resistance. Here, we used a functional re-452
sistance training program in females with CLBP and453
we have reported significant improvements in mus-454
cular strength and balance. The improvements in the455
musculoskeletal system were translated into reduced456
pain, disability and improved HRQOL. The data sug-457
gest 3 important points for rehabilitating CLBP: 1) the458
effectiveness of using a progressive functional resis-459
tance training program, 2) the relevance of including460
in the exercise program both symmetric and asymmet-461
ric loads, and 3) the need for controlling the quality462
of the movement during each exercise. Future research463
should focus on functional resistance training as a form464
of CLBP rehabilitation, its effects on different popu-465
lations (men or women with higher rates of disability466
and pain, different age groups) and the time-course ef-467
fects of this training regime and detraining. There is468
also a need for studies comparing the effects of FRT469
with other exercise methods.470
The present study also included some limitations.471
There was a lack of practitioner and participant blind-472
ing, although our results are consistent with the litera-473
ture. The sample size of the study does not allow for474
generalization of the results. The reason for this rela-475
tively small sample was the need for constant control 476
and feedback about the quality of movement during all 477
exercises of the intervention. Finally, the conclusions 478
of this study must be taken with caution when consid- 479
ering patients with different age, gender, and previous 480
physical activity level or background symptoms. 481
Acknowledgments 482
The authors wished to thank the Fisioterapia Lledó 483
by the logistical support. This study was supported by 484
grant: DEP2011-30009-C02-01 from the Spanish Min- 485
istry of Economy and Competitiveness. 486
Conflict of interest 487
None to report. 488
References 489
[1] Andersson GB. Epidemiological features of chronic low-back 490
pain. Lancet. 1999; 354(9178): 581-5. 491
[2] Panjabi MM. Clinical spinal instability and low back pain. J 492
Electromyogr Kinesiol. 2003; 13(4): 371-9. 493
[3] Hayden JA, van Tulder MW, Malmivaara AV, Koes BW. 494
Meta-analysis: Exercise therapy for nonspecific low back 495
pain. Ann Intern Med. 2005; 142(9): 765-75. 496
[4] Bergmark A. Stability of the lumbar spine, A study in me- 497
chanical engineering. Acta Orthop Scand Suppl. 1989; 230: 498
1-54. 499
[5] Henchoz Y, Kai-Lik So A. Exercise and nonspecific low back 500
pain: A literature review. Joint Bone Spine. 2008; 75(5): 533- 501
9. 502
[6] Bendix AF, Bendix T, Ostenfeld S, Bush E, Andersen A. Ac- 503
tive treatment programs for patients with chronic low back 504
pain: A prospective, randomized, observer-blinded study. Eur 505
Spine J. 1995; 4(3): 148-52. 506
[7] Ferreira ML, Ferreira PH, Latimer J, Herbert RD, Hodges 507
PW, Jennings MD, et al. Comparison of general exercise, 508
motor control exercise and spinal manipulative therapy for 509
chronic low back pain: A randomized trial. Pain. 2007; 131 510
(1-2): 31-7. 511
[8] Kell RT, Asmundson GJ. A comparison of two forms of pe- 512
riodized exercise rehabilitation programs in the management 513
of chronic nonspecific low-back pain. J Strength Cond Res. 514
2009; 23(2): 513-23. 515
[9] Kuukkanen T, Malkia E, Kautiainen H, Pohjolainen T. Ef- 516
fectiveness of a home exercise programme in low back pain: 517
A randomized five-year follow-up study. Physiother Res Int. 518
2007; 12(4): 213-24. 519
[10] Niemisto L, Lahtinen-Suopanki T, Rissanen P, Lindgren KA, 520
Sarna S, Hurri H. A randomized trial of combined manipu- 521
lation, stabilizing exercises, and physician consultation com- 522
pared to physician consultation alone for chronic low back 523
pain. Spine. 2003; 28(19): 2185-91. 524
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 10
10 J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain
[11] Aure OF, Nilsen JH, Vasseljen O. Manual therapy and exer-525
cise therapy in patients with chronic low back pain: A ran-526
domized, controlled trial with 1-year follow-up. Spine. 2003;527
28(6): 525-31.528
[12] Shaughnessy M, Caulfield B. A pilot study to investigate the529
effect of lumbar stabilisation exercise training on functional530
ability and quality of life in patients with chronic low back531
pain. Int J Rehabil Res. 2004; 27(4): 297-301.532
[13] Goldby LJ, Moore AP, Doust J, Trew ME. A randomized533
controlled trial investigating the efficiency of musculoskele-534
tal physiotherapy on chronic low back disorder. Spine. 2006;535
31(10): 1083-93.536
[14] Hemmila HM. Quality of life and cost of care of back pain537
patients in Finnish general practice. Spine. 2002; 27(6): 647-538
53.539
[15] Sullivan AB, Scheman J, Venesy D, Davin S. The role of ex-540
ercise and types of exercise in the rehabilitation of chronic541
pain: Specific or nonspecific benefits. Curr Pain Headache542
Rep. 2012; 16(2): 153-61.543
[16] Comerford MJ, Mottram SL. Movement and stability dys-544
function – contemporary developments. Man Ther. 2001;545
6(1): 15-26.546
[17] Mok NW, Brauer SG, Hodges PW. Hip strategy for balance547
control in quiet standing is reduced in people with low back548
pain. Spine (Phila Pa 1976). 2004; 29(6): E107-12.549
[18] O’Sullivan PB, Burnett A, Floyd AN, Gadsdon K, Logiudice550
J, Miller D, et al. Lumbar repositioning deficit in a specific551
low back pain population. Spine. 2003; 28(10): 1074-9.552
[19] Brumagne S, Cordo P, Lysens R, Verschueren S, Swinnen553
S. The role of paraspinal muscle spindles in lumbosacral po-554
sition sense in individuals with and without low back pain.555
Spine (Phila Pa 1976). 2000; 25(8): 989-94.556
[20] Anderson K, Behm DG. The impact of instability resistance557
training on balance and stability. Sports Med. 2005; 35(1):558
43-53.559
[21] Harding VR, Williams AC, Richardson PH, Nicholas MK,560
Jackson JL, Richardson IH, et al. The development of a bat-561
tery of measures for assessing physical functioning of chronic562
pain patients. Pain. 1994; 58(3): 367-75.563
[22] Radebold A, Cholewicki J, Polzhofer GK, Greene HS. Im-564
paired postural control of the lumbar spine is associated with565
delayed muscle response times in patients with chronic id-566
iopathic low back pain. Spine (Phila Pa 1976). 2001; 26(7):567
724-30.568
[23] Barr KP, Griggs M, Cadby T. Lumbar stabilization: A review569
of core concepts and current literature, part 2. Am J Phys Med570
Rehabil. 2007; 86(1): 72-80.571
[24] Kavcic N, Grenier S, McGill SM. Determining the stabiliz-572
ing role of individual torso muscles during rehabilitation ex-573
ercises. Spine (Phila Pa 1976). 2004; 29(11): 1254-65.574
[25] McGill SM, Grenier S, Kavcic N, Cholewicki J. Coordination575
of muscle activity to assure stability of the lumbar spine. J576
Electromyogr Kinesiol. 2003; 13(4): 353-9.577
[26] Thompson CJ, Cobb KM, Blackwell J. Functional training578
improves club head speed and functional fitness in older579
golfers. J Strength Cond Res. 2007; 21(1): 131-7.580
[27] de Vreede PL, Samson MM, van Meeteren NL, Duursma581
SA, Verhaar HJ. Functional-task exercise versus resistance582
strength exercise to improve daily function in older women: A583
randomized, controlled trial. J Am Geriatr Soc. 2005; 53(1):584
2-10.585
[28] McGill S. Core training: Evidence translating to better perfor-586
mance and injury prevention. Strength and Conditioning Jour-587
nal. 2010; 32(3): 33-46.588
[29] Abenhaim L, Rossignol M, Valat JP, Nordin M, Avouac B, 589
Blotman F, et al. The role of activity in the therapeutic man- 590
agement of back pain, Report of the international paris task 591
force on back pain. Spine. 2000; 25(4 Suppl): 1S-33S. 592
[30] Jensen MP, Miller L, Fisher LD. Assessment of pain during 593
medical procedures: A comparison of three scales. The Clini- 594
cal Journal of Pain. 1998; 14(4): 343-9. 595
[31] Fairbank JC, Couper J, Davies JB, O’Brien JP. The oswestry 596
low back pain disability questionnaire. Physiotherapy. 1980; 597
66(8): 271-3. 598
[32] Alonso J, Prieto L, Antó JM. La versión española del SF- 599
36 health survery (Cuestionario de Salud SF-36): Un instru- 600
mento para la medida de los resultados clínicos. Med Clin 601
Barc. 1995; (104): 771. 602
[33] Lee RC, Wang Z, Heo M, Ross R, Janssen I, Heymsfield 603
SB. Total-body skeletal muscle mass: Development and cross- 604
validation of anthropometric prediction models. Am J Clin 605
Nutr. 2000; 72(3): 796-803. 606
[34] Withers RT, Norton KI, Craig NP, Hartland MC, Venables W. 607
The relative body fat and anthropometric prediction of body 608
density of South Australian females aged 17-35 years. Eur J 609
Appl Physiol. 1987; 56(2): 181-90. 610
[35] McGill SM, Childs A, Liebenson C. Endurance times for 611
low back stabilization exercises: Clinical targets for testing 612
and training from a normal database. Archives of Physical 613
Medicine and Rehabilitation. 1999; 80(8): 941-4. 614
[36] Carter JM, Beam WC, McMahan SG, Barr ML, Brown LE. 615
The effects of stability ball training on spinal stability in 616
sedentary individuals. J Strength Cond Res. 2006; 20(2): 429- 617
35. 618
[37] ACSM. Handbook for the evaluation and prescription of ex- 619
ercise. Barcelona: Paidotribo; 1999. 620
[38] O’Sullivan PB. Lumbar segmental ‘instability’: Clinical pre- 621
sentation and specific stabilizing exercise management. Man 622
Ther. 2000; 5(1): 2-12. 623
[39] Koumantakis GA, Watson PJ, Oldham JA. Trunk muscle sta- 624
bilization training plus general exercise versus general exer- 625
cise only: Randomized controlled trial of patients with recur- 626
rent low back pain. Phy Ther. 2005; 85(3): 209-25. 627
[40] McGill SM. Low back stability: From formal description to 628
issues for performance and rehabilitation. Exerc Sport Sci 629
Rev. 2001; 29(1): 26-31. 630
[41] Santana JC. Functional training, breaking the bonds of tra- 631
ditionalism. Boca Raton: Optimum Performance Systems; 632
2000. 633
[42] Robertson RJ, Goss FL, Rutkowski J, Lenz B, Dixon C, Tim- 634
mer J, et al. Concurrent validation of the OMNI perceived ex- 635
ertion scale for resistance exercise. Medicine and Science in 636
Sports and Exercise. 2003; 35(2): 333-41. 637
[43] Cooper H, Hedges L, Valentine J. The handbook of research 638
synthesis and meta-analysis. New York. Russell Sage Foun- 639
dation; 2009. 640
[44] Tsigilis N, Douda H, Tokmakidis SP. Test-retest reliability 641
of the eurofit test battery administered to university students. 642
Perceptual and Motor Skills. 2002; 95(3): 1295-1300. 643
[45] Alonso J, Regidor E, Barrio G, Prieto L, Rodriguez C, 644
de la Fuente L. Population reference values of the Spanish 645
version of the Health Questionnaire SF-36. Med Clin (Barc). 646
1998; 111(11): 410-6. 647
[46] Mannion AF, Balague F, Pellise F, Cedraschi C. Pain mea- 648
surement in patients with low back pain. Nature Clinical Prac- 649
tice. 2007; 3(11): 610-8. 650
[47] Mannion AF, Muntener M, Taimela S, Dvorak J. A random- 651
ized clinical trial of three active therapies for chronic low back 652
corrected proof version
Galley Proof 7/09/2017; 10:02 File: bmr–1-bmr169684.tex; BOKCTP/xhs p. 11
J.M. Cortell-Tormo et al. / Functional resistance training in low-back pain 11
pain. Spine. 1999; 24(23): 2435-48.653
[48] Gur A, Karakoc M, Cevik R, Nas K, Sarac AJ, Karakoc M.654
Efficacy of low power laser therapy and exercise on pain and655
functions in chronic low back pain. Lasers Surg Med. 2003;656
32(3): 233-8.657
[49] Yozbatiran N, Yildirim Y, Parlak B. Effects of fitness and658
aquafitness exercises on physical fitness in patients with659
chronic low back pain. The Pain Clinic. 2004; (16): 35-42.660
[50] Kuukkanen TM, Malkia EA. An experimental controlled661
study on postural sway and therapeutic exercise in subjects662
with low back pain. Clin Rehabil. 2000; 14(2): 192-202.663
[51] Rasmussen-Barr E, Nilsson-Wikmar L, Arvidsson I. Stabiliz- 664
ing training compared with manual treatment in sub-acute and 665
chronic low-back pain. Man Ther. 2003; 8(4): 233-41. 666
[52] Descarreaux M, Normand MC, Laurencelle L, Dugas C. Eval- 667
uation of a specific home exercise program for low back pain. 668
J Manipul Physiol Ther. 2002; 25(8): 497-503. 669
[53] Hodges PW, Richardson CA. Inefficient muscular stabiliza- 670
tion of the lumbar spine associated with low back pain. A mo- 671
tor control evaluation of transversus abdominis. Spine. 1996; 672
21(22): 2640-50. 673
corrected proof version
