Maja PETRIČ 1*   , Lijana ZALETEL-KRAGELJ 2   , Renata VAUHNIK 1 
THE EFFECT OF A HATHA YOGA EXERCISE PROGRAMME WITH SEGMENTAL 
STABILISATION EXERCISES ON TRUNK FLEXIBILITY
1 Department of Physiotherapy, Faculty of Health Sciences, University of 
Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia
2 Chair of Public Health, Faculty of Medicine, University of Ljubljana, Zaloška cesta  4, 1000 Ljubljana, Slovenia
Received: Apr 09, 2025
Accepted: May 26, 2025
Original scientific article
*Correspondence: maja.petric@zf.uni-lj.si
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
152
UČINEK HATHA JOGE, STOPNJEVANE PO NAČELIH SEGMENTNE 
STABILIZACIJE HRBTENICE IN MEDENICE, NA GIBČNOST TRUPA
© National Institute of Public Health, Slovenia. 
Petrič M, Zaletel-Kragelj L, Vauhnik R. The effect of a hatha yoga exercise programme with segmental stabilisation exercises on trunk flexibility. Zdr Varst. 2025;64(3):152-159.  
doi: 10.2478/sjph-2025-0019
ABSTRACT
Keywords
Stabilisation 
exercise
Prevention
Low back pain
IZVLEČEK
Ključne besede 
stabilizacijska 
vadba
preventiva
bolečina v 
spodnjem delu 
hrbta
Introduction
In addition to sufficient trunk muscle endurance, adequate trunk flexibility, i.e. trunk muscle extensibility and spinal 
mobility, is an important element for the stability of the spine and pelvis. The aim of this intervention study was to 
investigate the effects of a preventive exercise programme on trunk flexibility. 
Methods
The participants were healthy adults without pain or injury in the lower back. They were divided into two groups: 
the exercise group (EG), which performed a hatha yoga exercise programme with segmental stabilisation exercises 
(12 weeks), and the control group (CG), in which they maintained their previous lifestyle during the study period. 
Before and after the intervention the measured variables, the extensibility of the trunk muscles and the mobility of 
the thoracolumbar spine were compared.
Results
Seventy-two participants (nEG=36, age 32.2±6.8 years; nCG=36, age 29.9±7.8 years) took part in the study. After the 
exercise programme, the EG participants achieved significantly better extensibility of the iliopsoas muscle (p≤0.001), 
the V-Sit and Reach Test (p=0.001) and the mobility of the thoracolumbar spine (p<0.05). Significant differences 
between the two groups were found in four of five extensibility tests (p≤0.041) and in flexion, left lateral flexion and 
right rotation of the spine (p≤0.036). 
Conclusions
The proposed exercise programme indicated a significant improvement in trunk flexibility. Future studies should 
investigate the long-term effects of the proposed exercise programme on a larger number of participants.
Uvod
Poleg primerne vzdržljivosti mišic trupa predstavljata pomembna elementa sistema stabilnosti hrbtenice in medenice 
tudi primerna raztegljivost mišic trupa in ustrezna gibljivost hrbtenice. Namen raziskave je bil preveriti učinke hatha 
joge, stopnjevane po načelih segmentne stabilizacije hrbtenice in medenice, na gibčnost trupa. 
Metode
V raziskavo so bili vključeni zdravi odrasli brez bolečin in/ali poškodb hrbtenice in medenice, ki pred vključitvijo 
v raziskavo niso redno izvajali vadb za izboljšanje raztegljivosti mišic in/ali gibljivosti hrbtenice. Razdeljeni so 
bili v dve skupini: vadbeno (VS), v kateri so v obdobju treh mesecev, dvakrat na teden po 60 minut, izvajali hatha 
jogo, stopnjevano po načelih segmentne stabilizacije hrbtenice in medenice; ali v primerjalno (PS), v kateri niso 
spreminjali svojega trenutnega življenjskega sloga. Ob vključitvi v raziskavo (PRED) in po končanem trimesečnem 
vadbenem obdobju (PO) je bila merjena raztegljivost mišic trupa in kolka ter gibljivost prsno-ledvenega dela hrbtenice. 
Analizirane so bile spremembe merjenih spremenljivk (PRED-PO, VS-PS). 
Rezultati
V raziskavi je sodelovalo 72 preiskovancev (nVS = 36, stari 32,2 ± 6,8 let; nPS = 36, stari 29,9 ± 7,8 let). Preiskovanci VS so po 
zaključku vadbenega programa dosegli statistično značilno boljšo raztegljivost mišice iliopsoas in rezultat testa V-doseg 
sede (p ≤ 0,001) ter gibljivost prsno-ledvenega dela hrbtenice (p < 0,05). Med skupinama VS in PS so bile statistično 
značilne razlike ugotovljene pri štirih od petih testov raztegljivosti mišic (p ≤ 0,041) ter pri izboljšanju obsega fleksije, 
lateralne fleksije v levo ter rotacije hrbtenice v desno stran (p ≤ 0,036). 
Zaključki
S hatha jogo, stopnjevano po načelih segmentne stabilizacije hrbtenice in medenice, lahko pomembno izboljšamo gibčnost 
trupa, in sicer tako z vidika boljše raztegljivosti nekaterih mišic kot tudi gibljivosti prsno-ledvenega dela hrbtenice. V 
nadaljnjih raziskavah bi bilo smiselno preveriti še dolgoročne učinke vadbenega programa na večjem vzorcu preiskovancev.
1 INTRODUCTION
Low back pain (LBP) is an important global public 
health problem (1). In 2019, LBP was the leading cause 
of functional disability (2) and maintained its leading 
position in recent years (1). Preventive measures to reduce 
the incidence of LBP have the potential to significantly 
reduce the burden associated with this condition. There is 
moderate evidence that an exercise programme alone or 
in combination with education is effective in reducing the 
risk of a future episode of LBP (3).
The normal function of the spine stabilising system is to 
provide the spine with sufficient stability to accommodate 
momentary fluctuations in stability demands due to changes 
in spinal posture and static and dynamic loading (4). Trunk 
flexibility (i.e. muscle extensibility and joint mobility) and 
trunk muscle endurance are interrelated: any factor that 
reduces the extensibility of the muscle-tendon structures 
and/or the joint mobility of the spine also has a negative 
effect on muscular endurance and vice versa, which 
increases the risk of LBP (5). Research in this area suggests 
that reduced trunk muscle endurance, reduced lateral spinal 
flexion, reduced hamstring extensibility and reduced lumbar 
lordosis are important risk factors for musculoskeletal 
overload of the spine and the occurrence of LBP (6, 7).
Hatha yoga is one of the traditional types of yoga 
that emphasises the importance of physical fitness 
through various postures (asanas), breathing techniques 
(pranayamas), relaxation and concentration techniques, 
etc. (8, 9). In recent years, yoga has been increasingly 
studied as one of the effective treatment strategies 
for LBP (10). However, most of the available studies in 
the field of yoga research investigated the efficacy 
and appropriateness of yoga as a therapeutic approach 
in (chronic) LBP patients, while less is known about its 
preventive outcomes (11, 12).
When hatha yoga is combined with segmental stabilisation 
exercises, the endurance of the trunk muscles increases 
(13). Since adequate trunk flexibility is also a very 
important factor for spinal and pelvic stability, the 
effect of the above combination of exercises on muscle 
extensibility and joint mobility must also be investigated. 
The objective of this study was to investigate the 
effectiveness of a professional and scientifically based 
hatha yoga exercise programme that integrates the 
principles of the segmental stabilisation exercise model to 
improve muscle extensibility and spinal mobility in healthy 
adults, in order to provide evidence for an effective 
health intervention to prevent LBP or reduce the risk of 
recurrence of LBP.
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
153
2 MATERIALS AND METHODS
2.1 Study design, time frame and setting
The study was part of a larger intervention study (non-
randomised controlled trial), and other parts of the study 
have already been published (13-15). It was conducted 
from September 2019 to March 2022 at the Faculty of 
Health Sciences of the University of Ljubljana (Slovenia).
2.2 Study participants
Potential candidates were invited to participate in the 
study via electronic media and chain reference sampling. 
The following inclusion criteria were considered for 
participation in the study: 1) healthy adults aged between 
20 and 45 years, 2) without LBP at the time of enrolment 
in the study, 3) without musculoskeletal injuries or other 
conditions that could be a contraindication or pose a risk 
to the individual’s health, and 4) without yoga practice or 
spinal stabilisation exercise programmes (continuous, at 
least once a week) in the last six months. All participants 
who met the inclusion criteria signed an informed consent 
form when participating in the study.
Participants were assigned to one of two study groups: a) 
an exercise group (EG) or b) a control group (CG) according 
to the case-control matching method (16), considering 
gender, age and physical activity. The EG participants took 
part in a three-month exercise programme (see below for 
more information on exercise), while the CG participants 
were asked to maintain their current lifestyle and level of 
physical activity during the study period. At the end of 
the study, CG participants were offered participation in 
the exercise programme.
2.3 Study instruments and protocols
First, the inclusion criteria were checked using a 
questionnaire on the participants’ demographic data, 
health status and physical activity (17). If all inclusion 
criteria were met, the participants’ height (in metres) and 
weight (in kilogrammes) were then measured.
Muscle extensibility measurements were then performed. 
The following tests were used: 1) modified Thomas test 
(18) for the extensibility of the iliopsoas and rectus 
femoris (in °, using a universal plastic goniometer 
(Baseline measurement instruments, USA)) and 2) V-Sit 
and Reach Test (19) for the flexibility of the lower back 
and hamstring (in cm; using a measuring tape (Enraf 
Nonius, Netherlands)).
The last series of measurements consisted of linear 
measurements of the mobility of the thoracolumbar part 
of the spine (in cm), specifically: thoracolumbar flexion 
(20, 21), extension (20), lateral flexion (left and right) (20) 
and rotation (left and right) (22).
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
All measurements described above were performed twice 
in the study: for the first time at enrolment (“BEFORE” 
measurements) and for the second time after the three-
month study period (i.e. after completion of the exercise 
programme (EG participants) or after the three-month 
study period without exercise (CG participants); “AFTER” 
measurements). For clinically significant differences, a 
difference of ≥5.0° in goniometric measurements and ≥1.3 
cm in tape measure measurements was used (23, 24). 
2.4 Exercise programme
The exercise programme is based on hatha yoga practised 
according to the principles of the segmental stabilisation 
exercise model. A three-month exercise programme 
comprised a total of 25 training sessions, which were 
carried out twice a week for 60 minutes each. It consisted 
of yoga postures (asanas) and controlled breathing 
techniques (pranayamas). In accordance with the three-
stage model of segmental stabilisation exercises (25), the 
contraction of the deep trunk muscles was emphasised in 
each asana, different positions or dynamic movements of 
the lower/upper limbs (in closed or open chain) during the 
holding of the basic asana were performed progressively, 
and so forth. Each training session began with 10 minutes 
of gradual warm-up exercises, followed by the main part 
of the training session to improve the endurance and 
flexibility of the trunk muscles (35 minutes) and gradual 
stretching and relaxation exercises at the end of the 
training session (15 minutes). All techniques and postures 
were gradually intensified during the exercise programme 
but remained in the range of low to moderate intensity 
exercises (ratings 9-15 on the Borg Rating of Perceived 
Exertion Scale 6-20) (26, 27).
Demographic characteristics of participants in EG and CG.
Legend: BMI=body mass index; EG=exercise group; n=number of participants; CG=control group
Characteristic Group p
EG (n=36)
x ̄ x ̄
CG (n=36)
SD SD
Table 1.
Age (years)
Body height (m)
Body mass (kg)
BMI (kg/m2)
32.2
1.69
65.9
23.2
29.9
1.69
67.2
23.4
6.8
0.06
9.7
3.2
7.8
0.08
13.2
3.6
0.187
0.680
0.662
0.866
154
The exercise programme and measurements were carried 
out by a physiotherapist (Master’s degree) who is also a 
yoga teacher (YT 500) and has several years of experience 
in these two professional fields. For implementation 
reasons, neither the participants nor the investigator 
were blinded. 
2.5 Methods of analysis
All collected variables were checked for distribution. 
Since not all variables were normally distributed and we 
were interested in the differences within each individual 
value, the parametric test was used when the variables 
were normally distributed and a corresponding non-
parametric test was used when the variables were not 
normally distributed. Changes in muscle extensibility and 
spinal mobility were compared between: 1) BEFORE and 
AFTER measurements using the t-test for related samples 
or the non-parametric Wilcoxon signed-rank test for 
related samples (BEFORE-AFTER comparison) and 2) EG 
and CG participants using the t-test for unrelated samples 
or the Mann-Whitney U-test for unrelated samples (EG-CG 
comparison). Statistical significance was set at p≤0.05 for 
all analyses. 
The data analysis was carried out using IBM SPSS Statistics 
27 (IBM, New York, USA) and an Excel programme 
(Microsoft Corporation, Washington, USA).
3 RESULTS
3.1 Participants
At the beginning of the study, 85 participants met all 
inclusion criteria, of whom 13 participants withdrew from 
the study for various reasons (e.g. pregnancy, significant 
change in physical activity level and/or lifestyle). 
Seventy-two participants completed the study, including 
36 participants in the EG (7 men and 29 women) and 36 
participants in the CG (8 men and 28 women). There were 
no significant differences in baseline data between EG and 
CG participants (Table 1).
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
155
Results of muscle extensibility of the lower back and hip muscles (comparison of BEFORE-AFTER measurements).
Legend: EG=exercise group; n=number of participants; CG=control group; L-IL=left iliopsoas muscle; R-IL=right iliopsoas 
muscle; L-RF=left rectus femoris muscle; R-RF=right rectus femoris muscle; V-SRT=V-Sit and Reach Test; m=measurement; 
BEFORE=measurements before the exercise programme; AFTER=measurements after the exercise programme; 95% CI=95% confidence 
interval; Me=median; Min.=minimum value; Max.=maximum value; a=Wilcoxon signed ranks test; b=paired samples t-test.
Group Test 95% CIx ̄ Mem SD pMin. Max.
Table 2.
EG (n=36)
CG (n=36)
L-IL (°)
R-IL (°)
L-RF (°)
R-RF (°)
V-SRT (cm)
L-IL (°)
R-IL (°)
L-RF (°)
R-RF (°)
V-SRT (cm)
13.7; 18.6
16.5; 20.7
13.6; 18.3
16.4; 21.0
51.3; 56.8
50.2; 55.2
52.5; 58.6
51.5; 56.9
5.8; 10.4
8.8; 12.5
16.1; 21.0
15.2; 20.8
15.9; 20.9
15.3; 20.3
49.6; 53.5
50.5; 55.8
50.9; 54.9
50.5; 55.7
4.6; 10.9
3.4; 9.9
16.1
18.6
15.9
18.7
54.1
52.7
55.5
54.2
8.1
10.6
18.6
18.0
18.4
17.8
51.6
53.1
52.9
53.1
7.8
6.6
17.0
19.5
16.5
19.0
54.0
54.0
55.5
56.0
9.0
11.3
18.0
17.5
18.0
17.0
52.0
53.0
52.0
55.0
7.0
6.0
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
7.3
6.2
6.9
6.9
8.1
7.4
9.0
8.0
6.9
5.5
7.3
8.4
7.4
7.3
5.8
7.8
5.9
7.7
9.3
9.6
0.001b
<0.001b
0.172b
0.265b
0.001b
0.501a
0.260a
0.257a
0.804b
0.031a
-1.0
6.0
3.0
7.0
35.0
31.0
36.0
34.0
-14.5
0.0
-6.0
-3.0
-7.0
-3.0
36.0
35.0
41.0
39.0
-25.0
-26.0
34.0
34.0
34.0
34.0
74.0
65.0
72.0
70.0
20.5
22.0
35.0
43.0
38.0
38.0
71.0
68.0
67.0
70.0
26.5
22.0
Participation in the training sessions was 85.1% (21.3 out of 
a total of 25 sessions). 
 
3.2 Effectiveness of the exercise programme
At baseline (BEFORE measurements), there were no 
significant differences between the EG and CG in muscle 
extensibility (p>0.05) or spinal mobility (p>0.05).
3.2.1 Muscle extensibility
A statistically significant improvement in the extensibility 
of the iliopsoas muscles was observed in the EG 
participants (p≤0.001). In the V-Sit and Reach Test, both 
groups achieved statistically significant BEFORE-AFTER 
differences; the EG participants improved the distance 
(p=0.001), and the CG participants achieved a worse 
distance on the second measurement (p=0.031). The 
changes in the other measures of muscle extensibility 
were not statistically significant (Table 2).
When comparing the mean BEFORE-AFTER difference 
between the two groups, the analysis showed statistically 
significant differences in four out of five extensibility tests 
(except for the right rectus femoris muscle; p>0.05) (Table 
3). The calculated Cohen’s d coefficients indicate a large 
effect, with the exception of the rectus femoris muscle, 
where the effect is small (Table 3). 
3.2.2 Spine mobility
The mobility of the thoracolumbar spine changed 
statistically significantly (p≤0.041) in the EG participants 
by at least ≥0.5 cm in all measured directions; except 
for the thoracolumbar extension movement, which 
decreased, the ranges of all other movements increased. 
In CG participants, a slight decrease in thoracolumbar 
spinal mobility (≤0.5 cm) was observed for most of the 
measured movements, but these changes were not 
statistically significant (Table 4).
156
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
Results of BEFORE-AFTER differences in muscle extensibility of the lower back and hip muscles (comparison of EG-CG 
measurements). 
Legend: L-IL=left iliopsoas muscle; R-IL=right iliopsoas muscle; L-RF=left rectus femoris muscle; R-RF=right rectus femoris muscle; 
V-SRT=V-Sit and Reach Test; EG=exercise group (n=36); CG=control group (n=36); x ̄ =mean BEFORE-AFTER difference; %=percentage of 
BEFORE-AFTER difference; Cohen’s d= Cohen’s d coefficient.
Test SDx ̄ pGroup % Cohen’s d
Table 3.
L-IL (°)
R-IL (°)
L-RF (°)
R-RF (°)
V-SRT (cm)
4.2
4.4
4.0
4.2
5.9
6.0
7.2
5.3
4.0
3.1
2.4
-0.6
2.8
-0.6
-1.4
1.6
-1.4
0.2
2.6
-1.2
0.004
<0.001
0.041
0.293
<0.001
EG
CG
EG
CG
EG
CG
EG
CG
EG
CG
15.1
-3.1
17.2
-3.2
-2.5
3.0
-2.5
0.4
31.6
-14.8
0.70
0.83
-0.50
-0.25
1.06
Results of mobility (in cm) of the thoracolumbar spine (comparison of BEFORE-AFTER measurements).
Legend: EG=exercise group; n=number of participants; CG=control group; FL=thoracolumbar flexion; EX=thoracolumbar extension; 
L-LF=left lateral spinal flexion; R-LF=right lateral spinal flexion; L-RO=left spinal rotation; R-RO=right spinal rotation; m=measurement; 
BEFORE=measurements before the exercise programme; AFTER=measurements after the exercise programme; 95% CI=95% confidence 
interval; Me=median; Min.=minimum value; Max.=maximum value; a=Wilcoxon signed ranks test; b=paired samples t-test.
Group Motion 95% CI
(cm)
x ̄
(cm)
Me
(cm)
m SD
(cm)
pMin.
(cm)
Max.
(cm)
Table 4.
EG (n=36)
CG (n=36)
FL
EX
L-LF
R-LF
L-RO
R-RO
FL
EX
L-LF
R-LF
L-RO
R-RO
7.9; 9.0
8.4; 9.5
2.4; 3.6
2.0; 2.8
18.3; 21.0
19.0; 21.6
18.4; 20.9
19.1; 21.6
7.7; 9.0
8.2; 9.6
7.9; 9.0
8.5; 9.7
8.5; 9.7
8.3; 9.4
2.2; 3.0
2.1; 3.0
19.4; 22.2
18.9; 21.8
19.5; 22.1
19.5; 22.2
7.7; 8.6
7.5; 8.5
7.8; 8.8
7.6; 8.8
8.4
8.9
3.0
2.4
19.6
20.3
19.6
20.3
8.3
8.9
8.5
9.1
9.1
8.8
2.6
2.5
20.8
20.3
20.8
20.8
8.2
8.0
8.3
8.2
8.5
9.0
3.0
2.0
19.5
20.0
19.5
20.0
8.5
9.0
8.5
9.0
9.0
8.5
2.3
2.5
21.3
20.3
21.0
21.5
8.0
8.0
8.3
8.0
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
BEFORE
AFTER
1.7
1.6
1.7
1.2
4.0
3.8
3.7
3.6
1.9
2.0
1.7
1.8
1.8
1.6
1.2
1.4
4.2
4.3
3.8
4.0
1.4
1.5
1.4
1.7
0.015b
0.038a
0.031a
0.041a
0.040b
0.003b
0.416a
0.777a
0.143b
0.854b
0.408b
0.666b
5.0
5.0
0.5
0.5
11.5
13.0
12.5
14.5
4.5
5.0
6.0
6.5
5.0
6.5
0.5
0.5
12.0
12.0
13.0
12.5
5.0
5.5
5.5
4.0
12.0
12.0
8.0
6.0
29.0
31.5
28.0
33.5
12.5
13.0
12.0
13.0
13.0
12.0
5.0
7.0
30.0
29.0
31.5
31.0
10.5
11.0
13.0
11.5
157
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
Results of BEFORE-AFTER differences in mobility (in cm) of the thoracolumbar spine (comparison of EG-CG measurements).
Legend: FL=thoracolumbar flexion; EX=thoracolumbar extension; L-LF=left lateral spinal flexion; R-LF=right lateral spinal flexion; 
L-RO=left spinal rotation; R-RO=right spinal rotation; EG=exercise group (n=36); CG=control group (n=36); x ̄ =mean BEFORE-AFTER 
difference; %=percentage of BEFORE-AFTER difference; a=Mann-Whitney U-test for unrelated samples; b=t-test for unrelated samples; 
Cohen’s d=Cohen’s d coefficient.
Motion SD (cm)x ̄  (cm) pGroup % Cohen’s d
Table 5.
FL
EX
L-LF
R-LF
L-RO
R-RO
1.1
1.4
1.5
1.3
1.8
1.8
1.9
1.8
1.5
1.2
1.2
1.3
0.5
-0.3
-0.6
-0.04
0.7
-0.5
0.7
0.1
0.6
-0.2
0.6
-0.1
0.036a
0.337a
0.010b
0.135b
0.082a
0.003a
EG
CG
EG
CG
EG
CG
EG
CG
EG
CG
EG
CG
5.8
-2.7
-19.0
-1.6
3.5
-2.2
3.7
0.3
6.5
-2.0
7.5
-1.2
0.64
-0.40
0.67
0.32
0.59
0.56
Statistically significant differences in the BEFORE-AFTER 
increase/decrease in thoracolumbar spine mobility were 
found between the EG and CG for thoracolumbar flexion, 
left lateral flexion and the right-sided rotation range 
(Table 5). The calculated Cohen’s d coefficients indicate a 
small to medium effect (Table 5).
4 DISCUSSION
Regular performance of the hatha yoga exercise 
programme with segmental stabilisation exercises led to 
statistically significant improvements in trunk flexibility. 
Participants in the EG achieved statistically significantly 
better results in four out of five extensibility tests and 
statistically significantly better spinal mobility in flexion, 
left lateral flexion and right rotation compared to the CG 
participants. The improvement in the V-Sit and Reach 
Test was also clinically significant in the EG participants. 
Compared to the EG participants, the CG participants 
showed no statistically or clinically significant changes in 
most of the observed variables and even tended to show 
a worsening of the results in the second measurement.
Considering that reduced hamstring and lower back muscle 
extensibility and limited spinal mobility are associated 
with a higher risk of LBP (6, 7), it makes sense to include 
exercises to improve trunk flexibility in preventive exercise 
programmes. By gradually intensifying the exercises and 
moving the spine in all directions and through the full 
range of motion, regular yoga practice also contributes to 
trunk flexibility (28, 29). The EG participants in our study 
achieved statistically significantly better extensibility of 
the iliopsoas muscles as well as the hamstring and lower 
back muscles, while in the CG statistically significantly 
poorer extensibility was indicated. The extensibility of 
the rectus femoris muscle did not change significantly in 
either group, and recent studies on risk factors suggest 
that poorer extensibility of the rectus femoris muscle 
does not correlate statistically significantly with the risk 
of LBP (6).
In a literature review on risk factors for LBP, Sadler et al. (6) 
also emphasised poorer mobility of the spine (particularly 
in the direction of lateral flexion) as an important risk 
factor. In our study, EG participants achieved statistically 
significantly better thoracolumbar spine mobility in all 
measured movements, except for extension, which was 
statistically significantly lower after completion of the 
exercise programme. The reason for this could be that the 
participants had better knowledge of the spinal stability 
system and higher trunk muscle tone after the three-
month preventive exercise programme, while they may 
have performed the extension movement of the spine 
in a different, more muscle-supported way. However, 
this remains an area for further research. In terms of 
comparability of the range of motion on the left and 
right side of spinal mobility in the anatomical frontal and 
transverse planes, the effect of the exercise programme 
was consistent in the increase in lateral flexion range of 
motion and both rotations, but not all improvements were 
statistically significant. For most CG participants, the 
ranges of the individual movements remained the same or 
were even slightly smaller in the second measurement than 
in the first measurement. The improvement in mobility 
of the EG participants is comparable to the results of a 
pilot study on the effects of a regular five-month hatha 
yoga practice on flexibility in healthy young women (30), 
in which the participants (n=9, mean age 23.8±2.9 years) 
achieved similar improvements in thoracolumbar spine 
mobility at the second measurement (after two months of 
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10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
practice) to those of the participants in our study (≥0.5 cm 
for each movement). Therefore, the hatha yoga exercise 
programme with segmental stabilisation exercises can 
improve spinal mobility.
In a literature review on the therapeutic effects of 
yoga on spinal mobility, Rathore et al. (31) emphasised 
that improvements in various aspects of spinal mobility, 
including flexion, extension and lateral flexion, were 
also observed in patients with chronic LBP. However, 
overstretching without integrating endurance exercises 
for the trunk muscles could have the opposite effect in 
symptomatic and asymptomatic individuals by increasing 
the risk of developing LBP (32). 
One limitation of the study is small sample size. In order 
to maintain the quality of the therapeutic exercise 
approach, participation in each training session of the 
exercise programme was limited to small groups (up to 
11 participants per group). Another limitation is the 
gender imbalance among the participants, as most of 
the participants were women. A further limitation is that 
randomisation of the participants into EG and CG groups 
was not possible for implementation reasons, as sufficient 
motivation and time of the participants was crucial for the 
implementation of the study (especially in the EG group 
for participation in the regular training sessions). Another 
limitation is the lack of clinically significant changes in 
most outcome measures, and the absence of blinding of 
both participants and investigators should be maintained 
in future studies if possible.
From the preventive point of view, despite the limitations, 
this study offers an important basis for using hatha yoga 
for preventive purposes. Moreover, through various 
techniques, hatha yoga strives for a dynamic balance 
between strength and flexibility that takes place on a 
physical, mental and emotional level (8, 9). Since sufficient 
endurance and extensibility of the trunk muscles together 
with sufficient mobility of the spine are the basis for spinal 
health and thus for the prevention of musculoskeletal 
complaints in the lower back, the strength of our study 
lies in the combination of exercises. The regular hatha 
yoga practice in combination with segmental stabilisation 
exercises improves muscle endurance in all four major 
trunk muscle groups (13, 14), but also the extensibility of 
most trunk and hip muscles and thoracolumbar mobility, 
as the results of our study showed. There is much evidence 
to suggest that yoga could be a suitable preventive 
approach in the management of LBP. Additionally, it could 
be an important preventive approach for maintaining 
physical fitness in seniors (33), as well as for maintaining 
good physical fitness in professions where the lower back 
is more stressed during work, e.g., in health professions 
such as physiotherapists or occupational therapists (34).
5 CONCLUSIONS
Hatha yoga with the segmental stabilisation exercises can 
significantly improve trunk flexibility both in terms of the 
extensibility of the back and hip muscles and the mobility 
of the spine in healthy participants. 
ACKNOWLEDGEMENTS
The authors would like to thank all participants for their 
co-operation. Special thanks go to Assistant Professor Dr 
Miroljub Jakovljević and yoga teacher Blaž Bertoncelj for 
their instructions and help in conducting the study.
INFORMED CONSENT
Written informed consent was obtained from all individual 
participants included in the study. The study was approved 
by National Medical Ethics Committee of the Republic 
of Slovenia (0120-220/2019/6), and all procedures were 
conducted in accordance with the Declaration of Helsinki.
CONFLICTS OF INTEREST
The authors declare that no conflicts of interest exist.
FUNDING
This work was supported by the Slovenian Research Agency 
(research core funding no. P3-0388 and no. P3-0429). The 
funders had no role in study design, data collection and 
analysis, or preparation of the manuscript.
ETHICAL APPROVAL
The study was approved by National Medical Ethics 
Committee of the Republic of Slovenia (0120-220/2019/6). 
AVAILABILITY OF DATA AND MATERIALS
The data presented in this study can be obtained upon 
request from the corresponding author.
AI USAGE STATEMENT
During the preparation of this article the authors did not 
use generative language models.
159
10.2478/sjph-2025-0019 Zdr Varst. 2025;64(3):152-159
PREPRINT STATEMENT
There is no preprint of this study.
ORCID 
Maja Petrič: 
https://orcid.org/0009-0002-0651-7599
Lijana Zaletel-Kragelj: 
https://orcid.org/0000-0003-1014-7906
Renata Vauhnik: 
https://orcid.org/0000-0003-0543-4919
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