STUDY PROTOCOLOpen Access
The effectiveness of a preferred intensity exercise
programme on the mental health outcomes of
young people with depression: a sequential
mixed methods evaluation
Tim Carter*, Patrick Callaghan, Elizabeth Khalil and Ioannis Morres
Background: People with mental illness are more likely to suffer physical health problems than comparable
populations who do not have mental illness. There is evidence to suggest that exercise, as well has having obvious
physical benefits, also has positive effects on mental health. There is a distinct paucity of research testing its effects
on young people seeking help for mental health issues. Additionally, it is generally found that compliance with
prescribed exercise programmes is low. As such, encouraging young people to exercise at levels recommended by
national guidelines may be unrealistic considering their struggle with mental health difficulties. It is proposed that
an exercise intervention tailored to young people’s preferred intensity may improve mental health outcomes,
overall quality of life, and reduce exercise attrition rates.
Methods/Design: A sequential mixed methods design will be utilised to assess the effectiveness of an individually
tailored exercise programme on the mental health outcomes of young people with depression. The mixed
methods design incorporates a Randomised Controlled Trial (RCT), focus groups and interviews and an economic
evaluation. Participants: 158 young people (14-17 years) recruited from primary care and voluntary services
randomly allocated to either the intervention group or control group. Intervention group: Participants will undertake
a 12 week exercise programme of 12 × 60 minutes of preferred intensity aerobic exercise receiving motivational
coaching and support throughout. Participants will also be invited to attend focus groups and 1-1 interviews
following completion of the exercise programme to illicit potential barriers facilitators to participation. Control
group: Participants will receive treatment as usual. Primary Outcome measure: Depression using the Children’s
Depression Inventory 2 (CDI-2). Secondary Outcome measures: Quality of Life (EQ-5D), physical fitness (Borg RPE
scale, heart rate), incidents of self-harm, treatment received and compliance with treatment, and the cost
effectiveness of the intervention. Outcome measures will be taken at baseline, post intervention and 6 month
Discussion: The results of this study will inform policy makers of the effectiveness of preferred intensity exercise
on the mental health outcomes of young people with depression, the acceptability of such an intervention to this
population and its cost effectiveness.
Trial Registration: ClinicalTrials.gov: NCT01474837
Keywords: Depression, Adolescence, Young people, Exercise, Physical activity
* Correspondence: Timothy.Carter@nottingham.ac.uk
School of Nursing, Midwifery & Physiotherapy, University of Nottingham,
Carter et al. BMC Public Health 2012, 12:187
© 2012 Carter et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
The Department of Health in England has identified
that people who use mental health services, in particular
those with diagnosis of schizophrenia or bipolar disor-
der, are at increased risk of coronary heart disease, dia-
betes, infections, respiratory disease and greater levels of
obesity . Additionally, it is reported that they are
almost twice as likely to die from coronary heart disease
and up to four times as likely to die from respiratory
disorder as those in the general population [2,3]. Conse-
quently, the Department of Health launched a national
initiative to improve the physical health of people with
mental illness with an aim to promote activity for all .
The numerous physical benefits of exercise have been
well evidenced throughout the years and are abundant
in health promotion literature in G.P surgerys, leisure
centres and gymnasiums. Engaging in exercise is asso-
ciated with reducing the risk of developing heart disease,
stroke, cancer, type 2 diabetes and obesity and promot-
ing musculoskeletal health . It improves the poor
physical health that leads to morbidity and early deaths
in mentally ill populations.
There is a breadth of evidence suggesting that exercise
also has positive effects on mental health. Generally it
has been found that exercise can have a positive impact
on mood, self esteem and self worth . Importantly, it
has also been shown to be effective at reducing symp-
toms of depression and anxiety, this has been evidenced
in both the general population [6-8] and in adult clinical
populations [9,10]. Although the evidence is scarce there
are some studies investigating the association of exercise
on mental health, in particular on depression in young
Drawing on evidence from a national school based
study looking into depression and suicidal ideation of
adolescents it was found that higher levels of depression
were associated with lower levels of sport participation.
After controlling for covariates it was reported that par-
ticipation in sports reduced the odds of suffering from
depression by 25% . Similar reports have been found
from longitudinal data; in a 6 Year study of 496 adoles-
cent students, in which assessments of physical activity
and depression scores were taken at 1-year intervals,
baseline physical activity predicted fewer depressive
symptoms over time . This finding is supported by
longitudinal studies [13,14].
Experimental data is scarce in the literature and
results are mixed; In an RCT comparing participants
receiving 24 sessions of aerobic activities of moderate
intensity compared to a light contact placebo group and
a non-treatment control group, participants in the inter-
vention group improved on measures of self-esteem
relative to the control group, however no differences
were shown on depression scores . Conversely, in an
RCT in which 66 Hispanic students were randomised to
an intervention group consisting of moderate intensity
aerobic exercise or a control group of low intensity phy-
sical activity over a 6 week period, depression scores
were significantly lower post intervention in the inter-
vention group .
Although there are a wealth of studies testing the
association between exercise and mental health in young
people in the general population, there is little data on
its association in clinical populations, i.e. those seeking
treatment for mental health issues. In a systematic
review of clinical trials up to 2005  only three trials
were found to have investigated the effect of exercise on
this population [18-20]. All three studies reported no
significant difference between depression scores in the
intervention and control groups. However, two of the
studies were reported to be of low quality and one was
rated as moderate; all three studies had relatively small
sample sizes. More recently there have been two studies
investigating the effects of exercise on young people in a
clinical population with slightly more positive results. In
a single measures design study, 15 female participants
meeting the Diagnostic & Statistical Manual for Mental
Disorders IV (DSM-IV) criteria for Post-Traumatic
Stress Disorder (PTSD) undertook an aerobic exercise
programme for 40 minutes 3 times a week for12 weeks.
Significant reduction in depression scores were reported
from baseline to mid intervention and post intervention.
However, a significant increase in depression scores was
reported at 1 month follow up when comparing post
intervention to 1 month. The authors conclude that
aerobic training may be an effective intervention for
childhood PTSD symptom reduction. However, increase
in depression scores at 1 month follow up suggests that
reduction in depression is not maintained when exercise
ceases . Another single case repeated measures
study using 12 female participants (aged 14-17) receiv-
ing treatment from a PTSD treatment centre in which
participants undertook 25 minute sessions of moderate
intensity aerobic exercise 3 times a week for 5 weeks
reported that 2 of the 8 participants who demonstrated
stable depression scores at baseline showed significant
reduction in depression scores post intervention. Impor-
tantly, both studies had inadequate sample sizes and no
control group and one had a large variance in the type
of physical activity participants undertook.
In summary, it is clear that there is potential for exer-
cise to have an effect on depression scores in young
adults with depression, however to the authors’ best
knowledge there has been no well designed RCT’s with
sufficient statistical power investigating this issue.
Furthermore, it is felt that encouraging young people to
Carter et al. BMC Public Health 2012, 12:187
Page 2 of 6
exercise at levels recommended by national guidelines,
or as prescribed by the researcher may be unrealistic for
young people with mental health difficulties. The
researchers’ previous work among young people sug-
gests that interventions tailored to young people’s pre-
ferred intensity may improve their motivation for
exercise and reduce attrition rates and lead to improved
mental health outcomes, increase self-esteem and overall
quality of life. Therefore, a specially designed pro-
gramme with exercise at a preferred intensity has the
potential to improve health outcomes in young people.
1. To determine the effectiveness of a preferred intensity
exercise programme on the mental health outcomes of
young people with depression.
2. To examine the acceptability of a preferred intensity
exercise programme to young people with depression
3. To determine the cost effectiveness of a preferred
intensity exercise programme for young people with
It is hypothesised that exercise of preferred intensity will
significantly lower depression scores, increase quality of
life, reduce incidents of self harm and be more cost-
effective than treatment as usual.
A sequential mixed methods design will be utilised and
consists of 3 parts: A Randomised Controlled Trial
(RCT), focus groups and interviews, and an economic
evaluation. The RCT: Participants will be randomly allo-
cated to preferred intensity aerobic exercise (interven-
tion arm) or treatment as usual (control arm). Outcome
measures, which will be collected independently of the
research team, will be captured at baseline, post-inter-
vention and six months follow-up. Qualitative data will
be collected through face-to-face qualitative interviews
and focus groups to understand potential barriers or
facilitators to participation. An economic evaluation will
also be conducted in order to assess the cost effective-
ness of the intervention.
Sample & recruitment
Participants will be young people aged 14-17 recruited
from Primary Care Services, Child and Adolescent Men-
tal Health Services and Voluntary Services in Notting-
ham City and County in the UK.
The initial approach will be from a member of the
patient’s usual care team who will be informed about
the study. The participants then will be referred by his/
her GP/Dr/Health Worker who believes that he/she may
benefit from this programme because he/she have been
having some difficulties with his/her mental health.
Inclusion Criteria - Young person to be aged between
14-17, receiving treatment for depression or scoring as
depressed on the Children’s Depression Inventory (CDI)
Exclusion Criteria- participants having any injury or
physical health problem or condition that precludes
Screening will take place by the potential participant’s
GP or Mental Health Professional who will be given a
flow chart of inclusion criteria. Alternatively, if the parti-
cipant has been referred by non mental health commu-
nity/voluntary services he/she will be screened by a
member of the research team who will administer the
Children’s Depression Inventory (CDI).
Primary outcome measure
The Children’s Depression Inventory 2(CDI-2) 
The CDI-2 consists of 28-items designed to assess
depression scores in young people aged 7 to 17. For
each item the there are three possible answers; 0 indi-
cating the absence of symptoms, 1 the mild symptoms,
and 2 the definite symptoms. The total score ranges
from 0 to 54. The CDI is sensitive to changes in depres-
sive symptoms over time and is a useful index of the
severity of the depressive syndrome.
Secondary outcome measures
European Quality of Life-5 Dimensions (EQ-5D)
The EQ-5D is a standardised measure of health-related
quality of life that provides a simple, generic measure of
health for clinical and economic appraisal.It comprises
five questions on mobility, self care, pain, usual activ-
ities, and psychological status with five possible answers
for each item (1 = no problem, 2 = slight problem, 3 =
moderate problem, 4 = severe problem, 5 = unable. It is
applicable to a wide range of health conditions and
treatments; it provides a simple descriptive profile and a
single index value for health status.
The Client Receipt of Service Inventory (CRSI)
The CSRI is a questionnaire that collects retrospective
information on service utilisation, service-related issues
and income in a manner commensurate with estimating
care package costs.
The Borg (RPE) Scale 
THE RPE scale is a simple method of rating perceived
exertion (RPE) and to gauge a person’s level of intensity
when exercising. It has an ordinal scale that ranges from
0-16 with verbal anchors allowing the participants to
Carter et al. BMC Public Health 2012, 12:187
Page 3 of 6
designate their level of intensity more accurately and for
answers to be standardized across individuals and tasks.
Resting Heart Rate
The number of incidents of self harm in the last 3
Compliance with intervention
The number of exercise session each participant
The intervention group will undertake 12 × 60 minute
aerobic exercise sessions, in groups of 5-10, tailored to
participants’ exercise levels and preferences led by a
qualified exercise therapist. The intervention group will
also receive psychosocial and motivational support
throughout each session to facilitate ongoing participa-
tion and enduring change. The motivational coaching
will consist of behaviour modification: goal setting, self-
monitoring, social support, enhancing self-efficacy and
Participants will have baseline measures taken at the
initial session. Outcome measures will be repeated at
post intervention in the final session and at 6 month fol-
low up at a location that suits the participant.
Participants in the intervention group will be invited
to participate in focus groups and face-to-face interviews
following completion of the exercise programme. These
will take place at a location agreed with participants and
researchers. It is hoped that these will be conducted at
the centres at which the exercise takes place. The data
will be recorded on an audio tape with the informed
consent from the participants and their legal guardians.
The facilitator will also take written notes which will
help identify the participants in the recording. Data will
be transcribed, coded and analysed for patterns, themes
and sub-categories, paying particular attention to out-
liers and rival explanations given by participants.
The control group will receive usual care throughout
the 12 week intervention period. Outcome measures will
be taken within the same week as the paired interven-
tion group; at baseline, post intervention (12 weeks
later) and at 6 month follow up.
Resource data will be collected for an economic eva-
luation using the Client Receipt of Service Inventory
(CSRI) which is a comprehensive inventory of resource
use that has been widely used in economic evaluations
of mental health interventions . Resource use will be
valued using published, and where appropriate patient
reported, unit costs. The primary measure for the cost
effectiveness analysis will be the SPPA (with sensitivity
analysis covering a range of possible outcomes). Asses-
sing health related quality of life using the EQ-5D will
enable a cost utility analysis to be undertaken for the
trial period. Using the information on costs and benefits
an incremental economic analysis comparing the tai-
lored exercise intervention to treatment as usual will be
undertaken to estimate mean cost-effectiveness. To test
the robustness of results in the face or any uncertainties,
and in order to improve the generalisability of results,
sensitivity analysis will be conducted. In addition, uncer-
tainty surrounding the cost-effectiveness of the tailored
exercise intervention will be presented graphically using
Cost-Effectiveness Acceptability Curves . Should the
data be skewed then non-parametric bootstrap analysis
using the percentile method confidence interval  will
be undertaken and incremental net benefits estimated.
The project steering group will be used to undertake
an implementation analysis of the project’s findings in
order to understand knowledge transfer from research
to clinical practice in the health service. Such an
approach is in line with MRC guidance for developing
and evaluating complex interventions . The MRC
guidance highlights that clinical ineffectiveness may be a
result of an implementation failure; as a result, it calls
for multi-level, process evaluations that may go beyond
RCTs to understand such failure. In the steering group
we intend to elicit from members the issues relating to
the uptake of the findings from the proposed study and
the barriers we may encounter in doing this. Each mem-
ber of the group will complete a proforma eliciting a
Social Network Analysis of their interactions with other
service providers to better understand the concerns of
providers not immediately associated with the project.
Sample size and justification
128 participants are required in order to have 80%
power to detect a difference in mean change of the pri-
mary outcome measure. This assumes equal standard
deviations of 16 points and using a pre-specified signifi-
cance level of p < 0.05. Assuming 20% attrition rates, it
is proposed to recruit 158 participants to the study (79
intervention arm, 79 control arm).
Stopping rules and discontinuation
The Trial will be stopped if there are significant adverse
events that cannot be remedied, if there is a significant
failure to recruit the required sample and if requested
by the funder or sponsor.
Randomisation and blinding
Allocated to experimental or control arm will be by
computer generated numbers by a researcher not asso-
ciated with the study. Measurements of baseline, out-
come and follow-up measures will be taken by a
researcher not associated with the study. Baseline out-
come measures will be taken after random allocation.
Carter et al. BMC Public Health 2012, 12:187
Page 4 of 6
The exercise therapist and focus group facilitator will
only know which participants get the exercise
SPSS V.18 will be used for the analysis of the results.
The two groups will be described in terms of their base-
line characteristics. Our primary outcome will be the
CDI post intervention. A regression model will be used
to compare the two groups in terms of the CDI score
post intervention conditional on baseline score. No
other confounders will be adjusted for unless there
appears to be an imbalance at baseline between the two
groups on pre-specified covariates that are considered to
influence outcome. For secondary outcomes, similar
models will be built all conditional on the relevant base-
line score in addition to baseline CDI score. Analyses
will be intention-to-treat and conducted on a dataset
where codes for the two intervention groups are unla-
beled. All estimates of effect sizes and numbers needed
to treat will be reported with 95% confidence intervals.
One of the potential problems with early studies testing
a relatively new intervention with a group in whom it is
largely untested is that the results may be skewed in a
positive direction. To minimise this potential effect, the
statistical analyses will be conducted independently of
the research team. Qualitative analysis of the focus
groups and interviews will be conducted using NVivo 9
in order to code the information and look for relevant
trends and themes within the data.
The study received ethical approval from Nottingham
Research Ethics Committee on 18/07/11. REC reference:
The results of this study will show whether preferred
intensity exercise has an effect on the mental health out-
comes of young people with depression and whether it
is acceptable to young people with depression.
CDI: Children’s depression inventory; CSRI: Client receipt of Service inventory;
DSM-IV: Diagnostic & statistical manual for mental disorders IV; EQ-5D:
European quality of life-5 dimensions; PTSD: Post-traumatic stress disorder;
RCT: Randomised controlled trial; RPE: Rating perceived exertion; SPSS:
Statistical package for the social sciences.
The study is funded by the National Institute of Mental Health, Research for
Patient Benefit Programme, grant reference number: PB-PG-1208-18097.
TC drafted the manuscript, co-authored the protocol and contributed to the
ethics submission. PC conceived of the study, co-authored the protocol and
contributed to the ethics submission. EK co-authored the protocol and
contributed to the ethics submission. IM co-authored the protocol. All
authors contributed to the design of the study, the study protocol and the
writing up of the paper. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Received: 6 February 2012 Accepted: 13 March 2012
Published: 13 March 2012
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The pre-publication history for this paper can be accessed here:
Cite this article as: Carter et al.: The effectiveness of a preferred
intensity exercise programme on the mental health outcomes of young
people with depression: a sequential mixed methods evaluation. BMC
Public Health 2012 12:187.
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