Sources of Variability in Physical Activity Among Inactive People
with Multiple Sclerosis
Marcin K. Uszynski
1,2
&
Matthew P. Herring
3,4
&
Blathin Casey
1
&
Sara Hayes
1,4
&
Stephen Gallagher
4,5
&
Robert W. Motl
6
&
Susan Coote
1,4
Published online: 10 July 2017
#
International Society of Behavioral Medicine 2017
Abstract
Purpose Evidence supports that physical activity (PA) im-
proves symptoms of multiple sclerosis (MS). Although appli-
cation of principles from Social Cognitive Theory (SCT) may
facilitate positive changes in PA behaviour among people with
multiple sclerosis (pwMS), the constructs often explain limit-
ed variance in PA. This study investigated the extent to which
MS symptoms, including fatigue, depression, and walking
limitations combined with the SCTconstructs, explained more
variance in PA than SCT constructs alone among pwMS.
Method Baseline data, including objectively assessed PA, ex-
ercise self-efficacy, goal setting, outcome expectations, 6-min
walk test, fatigue and depression, from 65 participants of the
Step It Up randomized controlled trial completed in Ireland
(2016), were included. Multiple regression models quantified
variance explained in PA and independent associations of (1)
SCT constructs, (2) symptoms and (3) SCT constructs and
symptoms.
Results Model 1 included exercise self-efficacy, exercise goal
setting and multidimensional outcomes expectations for exer-
cise and explained ~14% of the variance in PA (R
2
=0.144,
p < 0.05). Model 2 included walking limitations, fatigue and
depression and explained 20% of the variance in PA
(R
2
=0.196, p < 0.01). Model 3 combined models 1 and 2
and explained variance increased to ~29% (R
2
=0.288;
p<0.01). In Model 3, exercise self-efficacy (β=0.30,
p < 0.05), walking limitations (β=0.32, p < 0.01), fatigue
(β = −0.41, p < 0.01) and depression (β = 0.34, p < 0.05) were
significantly and independently associated with PA.
Conclusion Findings suggest that relevant MS symptoms im-
proved by PA, including fatigue, depression and walking lim-
itations, and SCT constructs together explained more variance
in PA than SCT constructs alone, providing support for
targeting both SCT constructs and these symptoms in the mul-
tifactorial promotion of PA among pwMS.
Keywords Multiple sclerosis
.
Physical activity
.
Social
cognitive correlates
.
Symptoms
Introduction
Physical activity (PA) and exercise improve symptoms among
people with MS (pwMS) [1]. However, pwMS are 2.5 times
more likely to report insufficient PA than healthy adults, [2].
We know little about factors that explain variability in PA
levels and can inform PA behaviour change interventions
and facilitate long-term adherence to PA and exercise.
The components of Social Cognitive Theory (SCT) [3],
including self-efficacy (SE), outcome expectations, enjoy-
ment and goal setting, could facilitate positive changes in PA
behaviour among pwMS. For example, recent evidence
among pwMS [4] supported small to moderate positive
* Marcin K. Uszynski
marcin.uszynski@ul.ie
1
Department of Clinical Therapies, Health Sciences Building,
University of Limerick, Limerick, Ireland
2
Multiple Sclerosis Society of Ireland, Western Regional Office,
Galway, Ireland
3
Department of Physical Education and Sport Sciences, University of
Limerick, Limerick, Ireland
4
Health Research Institute, University of Limerick, Limerick, Ireland
5
Department of Psychology, University of Limerick,
Limerick, Ireland
6
Department of Physical Therapy, University of Alabama at
Birmingham, Birmingham, AL, USA
Int.J. Behav. Med. (2018) 25:259–264
DOI 10.1007/s12529-017-9674-z
@Phil_Robichaud
@deepthiw
@JoseServera