STUDY PROTOCOL
Open Access
Effect of running therapy on depression
(EFFORT-D). Design of a randomised controlled
trial in adult patients [ISRCTN 1894]
Frank R Kruisdijk1,3*, Ingrid JM Hendriksen2,3, Erwin CPM Tak2,3, Aartjan TF Beekman4,5 and
Marijke Hopman-Rock2,3,5
Abstract
Background: The societal and personal burden of depressive illness is considerable. Despite the developments in
treatment strategies, the effectiveness of both medication and psychotherapy is not ideal. Physical activity,
including exercise, is a relatively cheap and non-harmful lifestyle intervention which lacks the side-effects of
medication and does not require the introspective ability necessary for most psychotherapies. Several cohort
studies and randomised controlled trials (RCTs) have been performed to establish the effect of physical activity on
prevention and remission of depressive illness. However, recent meta-analysis’s of all RCTs in this area showed
conflicting results. The objective of the present article is to describe the design of a RCT examining the effect of
exercise on depressive patients.
Methods/Design: The EFFect Of Running Therapy on Depression in adults (EFFORT-D) is a RCT, studying the
effectiveness of exercise therapy (running therapy (RT) or Nordic walking (NW)) on depression in adults, in addition
to usual care. The study population consists of patients with depressive disorder, Hamilton Rating Scale for
Depression (HRSD) ≥ 14, recruited from specialised mental health care. The experimental group receives the
exercise intervention besides treatment as usual, the control group receives treatment as usual. The intervention
program is a group-based, 1 h session, two times a week for 6 months and of increasing intensity. The control
group only performs low intensive non-aerobic exercises. Measurements are performed at inclusion and at 3,6 and
12 months.
Primary outcome measure is reduction in depressive symptoms measured by the HRSD. Cardio-respiratory fitness is
measured using a sub maximal cycling test, biometric information is gathered and blood samples are collected for
metabolic parameters. Also, co-morbidity with pain, anxiety and personality traits is studied, as well as quality of life
and cost-effectiveness.
Discussion: Exercise in depression can be used as a standalone or as an add-on intervention. In specialised
mental health care, chronic forms of depression, co-morbid anxiety or physical complaints and treatment
resistance are common. An add-on strategy therefore seems the best choice. This is the first high quality large
trial into the effectiveness of exercise as an add-on treatment for depression in adult patients in specialised
mental health care.
Trial registration: Netherlands Trial Register (NTR): NTR1894
* Correspondence: f.kruisdijk@ggzcentraal.nl
1GGZ Centraal Centers for Mental Health, Symfora-Meander Centre for
Psychiatry, Utrechtseweg 266, 3800 DB Amersfoort, The Netherlands
Full list of author information is available at the end of the article
Kruisdijk et al. BMC Public Health 2012, 12:50
http://www.biomedcentral.com/1471-2458/12/50
© 2012 Kruisdijk et al; 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.
Background
Depression is a common disorder. The lifetime preva-
lence of depressive disorders in Dutch adults is 19% [1].
Recurrence of symptoms occurs in an unfavourable and
fluctuating course in 44% and a severe chronic course in
32% of the patients. Depressive disorders obviously have
negative effects on wellbeing and daily personal and
professional functioning.
Antidepressants and psychotherapy
Treatment frequently includes prescription of antide-
pressants. However, the effectiveness of such treatment
may be limited because of poor compliance and limited
effectiveness. A recent analysis of data of the US Food
and Drugs Administration, showed relatively small drug-
placebo differences in antidepressant efficacy [2]. Other
disadvantages of antidepressants are unpleasant side
effects and increased risk of hypertension in depressed
patients combined with Diabetes Mellitus type II (DM
II) [3,4].
A systematic review of randomised controlled trials
into effectiveness and cost-effectiveness of brief psycho-
logical treatment for depression showed that some
forms,
especially
cognitive-behavioural
based
approaches, were beneficial in the treatment of outpati-
ents [5]. A meta-analysis, regarding a mostly adult popu-
lation, found a favourable outcome for a combination of
psychotherapy and pharmacotherapy compared to psy-
chological treatment alone for depression in the short-
term [6]. A recent meta-analysis examined whether the
quality of the studies investigating psychotherapy for
adult depression was associated with the effect-size
found in these studies [7]. It showed that the effects of
psychotherapy for adult depression have been overesti-
mated in meta-analytical studies. The authors stated
that the effects of psychotherapy are much smaller than
is assumed.
The traditional treatment strategies, medication and
psychotherapy, are still not ideal and a new intervention,
exercise, focusing on a different psychopathological
mechanism of depression is needed.
Exercise
Exercise is a potential alternative low-cost therapy, but
more studies are needed to define the place of exercise
in a stepped care program for depression [8]. Exercise is
relatively safe and has less negative side effects than
antidepressants. Obviously, exercise has also many bene-
ficial effects on physical health [9,10], and is expected to
have additional advantages in depressed patients who
suffer from a combination of mental and physical pro-
blems, such as pain complaints or increased risk of car-
diac morbidity. Exercise is suitable for most individuals,
participating in an exercise program promotes social
integration and successful adaptation can increase self-
esteem. Finally, exercise may reduce the negative side
effects of antidepressants, such as fatigue, thus increas-
ing compliance in medication use.
Scientific evidence for the efficacy of exercise
Recent reviews and meta-analyses suggest that exercise
leads to improvements in depressive symptoms [11,12].
Following the cumulative evidence from prospective
cohort studies and RCTs, exercise has proven protective
benefits for several aspects of mental health in general
and for symptoms of depression in particular. However,
study results on the curative effect on a present depres-
sion are conflicting. A recent Cochrane meta-analysis
[13], updating an earlier systematic review in 2001 by
Lawlor and Hopker [14], concluded that the statistically
weak findings didn’t support the efficacy of exercise in
the treatment of depression. Methodological weaknesses
of the trials were identified, including the lack of treat-
ment concealment, intention to treat analysis and a clin-
ical interview to confirm the diagnosis of depression.
Rethorst et al. [15] argue that the earlier mentioned
meta-analysis of Lawlor and Hopker suffered from
incomplete research data and a lack of moderating vari-
able analysis. The meta-analysis by Rethorst et al., with
58 RCTs included, calculated an overall effect size of
-0.80 for the effects of exercise on depression. The
recommendation of both Lawlor et al. and Rethorst et
al. is that further, conclusive research is still needed into
the use of exercise for depression. Exercise as an adjunct
to recognised treatments, such as psychotherapy and/or
medication, should also be studied. Furthermore, follow-
up research is needed that examines the sustainability of
the effects after exercise therapy has ended.
Very recently, Krogh et al. [16] performed a systematic
review and meta-analysis in which only 13 trials were
selected because of the stringent selection criteria used
(i.e. recording clinical depression according to any diag-
nostic system, adequate allocation concealment, blinded
outcome and intention to treat analysis). Besides an
inverse association between duration of intervention and
the magnitude of the association of exercise with
depression, the effect size was 0.40 for the pooled effect
sizes of 13 studies and 0.19 for the selected three high
quality design studies. The authors concluded that large
high quality design studies are required. The recommen-
dations from the three meta-analysis cited above are
integrated in the design of the EFFORT-D study.
Besides reduction of depressive symptoms, exercise
can be useful for other treatment indications, such as
cardiovascular condition, metabolic syndrome, pain
modulation and the immune system. Depression is
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associated with cardiovascular disease. It is an estab-
lished risk factor for mortality after acute myocardial
infarction. A recent meta-analysis of cohort studies also
shows the aetiological and prognostic effects of depres-
sion on coronary heart disease (CHD) [17]: the pooled
relative risk of depression on future coronary heart dis-
ease was 1.80. Another meta-analysis shows an overall
relative risk of dying in depressed subjects of 1.80 com-
pared to non-depressed subjects, with no major differ-
ences between men and women [18]. The increased
relative risk on mortality was also found in subclinical
forms of depression.
These findings suggest that exercise may also be pre-
scribed to improve the cardiovascular condition and
prevent future heart disease. Depressed patients should
also be more closely monitored regarding cardiovascular
parameters.
The body of evidence showing an association between
depression and obesity and metabolic deregulation is
growing. Recent meta-analysis of cross-sectional studies
in the general population found a significant positive
association between depression and obesity, affecting
women more than men. A reciprocal risk relation
between obesity and depression [19,20], and an U-
shaped, non-linear trend in the association between
BMI and depression was found [21]. The Dutch NESDA
study [22] shows an association between severity of
depression and unfavourable cholesterol high-hdl/low-
ldl concentration [23]. This tendency for a higher risk of
depression on metabolic syndrome, in which various
cardiovascular risk factors appear, emphasizes the need
of careful screening on this parameters [24], and exer-
cise could positively influence these parameters.
A recent meta-analysis of studies into cytokines in
depressed patients [25] showed that depression and an
activation of the immune-system do co-exist. Both
tumornecrosisfactor-a (TNF-a) and interleukine-6-con-
centration (IL-6) were significantly raised and C-reactive
protein (CRP) was linearly associated with several con-
ventional risk factors and inflammatory markers [26].
The relevance of CRP however still remains controver-
sial [27]. Therefore, measurement of CRP blood levels in
an intervention exercise study could contribute to a bet-
ter understanding of the clinical importance in relation
to heart condition.
The reciprocal relation between pain and depression
has been reported in several studies where Major
Depressive Disorder (MDD) was associated with chronic
pain (> 6 months) and nearly 50% of patients had at
least one chronic painful physical condition [28,29]. The
duration of depressive symptoms was found to be pro-
longed in the presence of chronic pain. The therapeutic
prognosis of co-morbid pain and depression is poor and
the pain-depression association was found to be
stronger in men than in women and in older adults
compared to younger. Productivity was decreased when
depression and pain existed in a co-morbid pattern [30].
Quality of life and cost-effectiveness
Systematic evaluation of cost-effectiveness and quality of
life, including life-events in the treatment of depression,
may contribute to the development of more evidence
based care models [31], for instance by disease
management.
A population sample study showed that, in patients
with a remitted MDD, the quality of life was lower than
in the general population. A higher depressive severity
was associated with a lower quality of life. Ten
Doesschate et al. argue that, even in depression in
remission, attention is needed for the quality of life, and
above that, residual symptoms must be treated aggres-
sively to achieve a higher quality of life [32].
Summarized aims and hypothesis of EFFORT-D
The main objective of the study is to assess the effec-
tiveness of exercise therapy (running therapy (RT) or
Nordic walking (NW)), in addition to usual care, on
depression in adult patients. We hypothesize that adding
exercise therapy to usual care will result in a larger
reduction in depressive symptoms (as measured with
the Hamilton Rating Scale of Depression, (HRSD)) dur-
ing a 6 month treatment program as well as at 6
months follow-up, compared to usual care without exer-
cise therapy.
Secondary aims are to assess the effectiveness of exer-
cise therapy (RT or NW) on the following outcome
measures: 1) Cardiovascular and metabolic risk para-
meters as fitness (VO2 max, grip strength), BMI, waist
circumference, body composition, blood pressure, fasting
blood glucose, cholesterol HDL/LDL ratio and CRP, 2)
Co-morbid symptoms of anxiety and pain 3) Quality of
life, and 4) Cost-effectiveness.
To assess whether there are subgroups of patients who
show a larger or less effect of exercise therapy on
depression, subgroup analysis will be conducted differ-
entiated on demographic variables (age, sex) and level
and type of depression based on the HRSD, personality
traits and level of fitness.
Methods/Design
EFFORT-D is a randomized controlled trial, designed
along the Consort-statement guidelines [33], in which
outpatients as well as hospitalised depressed patients
will be included and randomized in two groups: a con-
trol group or an intervention group (see flow chart in
Figure 1). The control group outpatients receive usual
care (i.e. anti-depressive medication and/or cognitive
and/or interpersonal therapy). The control group
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inpatients have their usual treatment program (consist-
ing of pharmacotherapy and/or sociotherapy, psy-
chotherapy, psycho-education and indicated nonverbal
therapies) and are allowed to exercise at low intensity as
part of their daily program.
The intervention group receives 6 months supervised
exercise therapy for 1 h a week and is instructed to
train unsupervised for 1 h a week during this period
(combined about 40 exercise sessions during the inter-
vention period). Both training sessions follow an indivi-
dualised intervention protocol and are in addition to the
usual care program.
Included and randomised patients in the intervention
group are invited to take part in Running Therapy (RT).
Patients will only be referred to Nordic Walking (NW)
in case of clear medical contra-indications against RT,
such as muscular-skeleton problems, or if patients have
a
strong
dislike
for
running
which
obstructs
participation and compliance. The study will run for 27
months, with an 18 months inclusion period during
which patients are recruited and randomized. There are
four measurements for each patient: at baseline (T0),
halfway the 6 month intervention period (T3), at the
end of the intervention period (T6), and at follow up, 12
months after baseline (T12). In Table 1 the timetable is
shown.
Study population
The study population consists of adult patients diag-
nosed by a clinician with a depression or bipolar disor-
der with depressive mood, who are or will be treated in
GGZ Centraal Mental Hospitals or Symfora-Meander
Hospital. Patients aged between 18-65, with a DSM-IV
diagnoses of unipolar, bipolar depression or seasonal
depression not responding to light therapy (10 sessions
of 1 h), a baseline Hamilton Rating Scale of Depression
Psychiatrist diagnosis of depression
In -or-outpatients
Screening by 
research-assistant
Check inclusion/
exclusion criteria
HRSD
Biometric values = BV
Cycle test = CT
Electronic Questionnary = EQ
Blood samples = BS
Blinded randomisation
by random envelopes
Control Group
Treatment as usual
Psychotherapy
Medication
Lifestyle
psychoeducation
Intervention Group
Treatment as usual
Psychotherapy
Medication
Lifestyle
psychoeducation
 +
20 sessions 1 hr. RT/NW supervised
20 sessions 1 hr. RT/NW individually 
HR freq. Polar
Informed consent
+
Inclusion in EFF-D
T= 0
T = 3  BV,CT,EQ
T = 6  BV,CT,EQ,BS
T = 12 BV,CT,EQ
End of 
Intervention period
Figure 1 Flow chart.
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Table 1 Events and time table
Intervention period
Follow-up period
Procedure
Source
Person
No. of items
Duration (min.)
T0
T3
T6
T12
Written informed consent
letter
patient
X
Demographics1
patient file
research assistant
X
Depression
Depression history2
patient file
research assistant
2
X
HRSD3
interview
blind rater
17
20
X
X
X
X
IDS-SR4
questionnaire
patient
30
10
X
X
X
X
Bearableness (VAS)
questionnaire
patient
1
X
X
X
X
Metabolic syndrome
Length
physical test
research assistant
1
X
Weight
physical test
research assistant
1
X
X
X
X
Waist circumference
physical test
research assistant
1
X
X
X
X
Blood pressure
physical test
research assistant
1
X
X
X
X
Smoking/alchohol intake
questionnaire
patient
1
X
X
X
X
Laboratory assesment6
physical test
laboratory
2
X
X
X
X
Quality of Life
WHO-DAS7
questionnaire
patient
36
X
X
X
X
Pain
GCPS8
questionnaire
patient
7
X
X
X
X
Bearableness (VAS)
questionnaire
patient
1
X
X
X
X
Anxiety
BAI9
questionnaire
patient
21
X
X
X
X
Cost effectiveness
TIC-P10
quest./pnt file
pnt/research assistant
26
X
X
X
Euroqol
questionnaire
patient
5
X
X
X
Subjective health (VAS)
questionnaire
patient
1
X
X
X
Fitness
Submaximal cycle test
physical test
research assistant
10
X
X
X
X
Grip strength
physical test
research assistant
2
X
X
X
X
Exercise intensity (HR)11
physical test
exercise instructor
during training sessions
Personality
NEO PI-R12
questionnaire
patient
60
X
Physical activity
SQUASH13
questionnaire
patient
12
X
X
X
X
Additional Measures
LEQ14
questionnaire
patient
12
X
X
X
X
Compliance
registration
exercise instructor
during training sessions
POMS15
questionnaire
patient
32
during training sessions
Evaluation Intervention16
questionnaire
patient
X
1: Date of birth, sex, education, ethnicity, income, professional status, living situation, marital status
2: Number and duration of former episodes, duration current episode
3: Hamilton Rating Scale of Depression (or HAMD)
4: Inventory of Depressive Symptomatology - Self Report
6: fasting glucose, triglycerides, total cholesterol, HDL- cholesterol, cholesterol/HDL-ratio, creatinine, MDRD
7: World Health Organisation- Disability Assessment Schedule
8: Graded Chronic Pain Scale
9: Beck Anxiety Inventory
10: Trimbos/iMTA questionnaire for Costs associated with Psychiatric Illness
11: Polar RS 800 CX Run
12: Revised NEO Personality Inventory
13: Short QUestionnaire to ASses Health enhancing physical activity
14: Life Events Questionnaire
15: Profile of Mood State
16: Only for patients who participated in the intervention
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(HRSD) score ≥14 and (will be) treated for depression,
are included.
Criteria for exclusion are: a depression as part of a
psychotic disorder, schizophrenia, schizoaffective disor-
der or obsessive compulsive disorder, anxiety disorder
as primary diagnosis, patients in long stay facilities
(including day-care) or with complex pathology and
treatment resistant depression (inpatients, treated by
protocol more than 6 months with no remission);
patients with significant cardiovascular disease or other
medical conditions as contra-indication for exercise
therapy, walking and/or running such as joint and hip
pathology; alcohol/drugs dependence as a primary diag-
nosis, pregnancy, high suicide risk with treatment on a
closed ward, or already being physically active on a reg-
ular basis (2-3 times a week on a high-intensity).
Sample size
Following earlier RCTs [34] it is expected that patients
in the usual care group (controls) will respond with a
mean reduction in HRSD of six points. Adding exercise
to usual care is expected to result in a decline of at least
eight points in HRSD score (thus two extra points). To
detect this difference, with an a (two-tailed) of 5% and a
power (1-b) of 80%, using two equal groups and a stan-
dard deviation of 5 points, 100 patients are needed in
each group. Taking 30% drop-out into account, 140
patients have to be included in each group.
Procedures and study instruments
Names of eligible patients with their registration number
of the electronic patient file (EPD) are provided by the
diagnosing psychiatrists to the research assistant, who
will make a first check on inclusion and exclusion cri-
teria, informs the participants and asks them to join the
study. Written informed consent will be obtained
according to prevailing legal requirements before the
start of the study. Eligible patients, HDRS ≥ 14 as pri-
mary outcome measure, perform the Åstrand submaxi-
mal cycling test, physical measures and fill out the
questionnaire, after which the participants are rando-
mized. All outcome parameters measured during base-
line will be repeated three, six and 12 months after
baseline, except for the blood samples (only at T0 and
T6). Height is measured according to protocol (Seca
214, Hamburg, Germany) and a bio-impedance scale is
used to measure weight and body composition (Omron
HBF-510, Omron Healthcare Europe BV, The Nether-
lands). Waist circumference is measured twice with a
tape measure (Seca 201, Hamburg, Germany) at the
midpoint between the lower border of the ribs and the
upper border of the pelvis. Systolic and diastolic blood
pressure are registered twice at rest, using an electronic
blood pressure meter (Omron M6 comfort, Omron
Healthcare Europe BV, The Netherlands) with an ade-
quate cuff size. Grip-strength is tested according to pro-
tocol using a hydraulic hand dynamometer (Jamar
J00105, Sammons Preston Rolyan, Bolingbrook, USA).
The submaximal Åstrand test [35] will be performed on
a stationary bicycle ergometer (Examiner, Lode BV, The
Netherlands) and the mean heart rate of the last 2 min
of the test will be used to estimate the VO2max. Heart
rate during this test is registered by a heart rate monitor
(Polar RS 800, Electro Oy, Finland).
Questionnaires
At each measurement moment the participant will be
asked to fill out a digital questionnaire containing the
following instruments:
Demographics and personal life events
Socio-demographic data are collected using standard
questions on age, sex, marital status, ethnicity and
household composition. Socio-economic variables
include highest education and income. Personal history
is evaluated by the Life Events Questionnaire (LEQ), a
12-item inventory-type questionnaire in which subjects
mark the exposure to negative life events such as unem-
ployment, separation from a partner and death of a
close family member which have occurred in the past
year [36].
Mental and physical health and its consequences
The Hamilton Rating Scale of Depression (HRSD) mea-
sures depression with a 17-item list performed by
trained interviewers [37]., using the Dutch translation of
the version of Bech et al. [38], in which the items of
depressive symptoms are extensively operationalised and
this version is often used in international research [39].
The Inventory of Depressive Symptomatology - Self-
Reported (IDS-SR) measures the severity of depression
with a 30-item self-report list [40]. It has good respon-
siveness to change and is more sensitive for atypical
depressive criteria than the HRSD. History of depression
is evaluated by a single question into the number and
duration of depressive episodes for which treatment was
necessary.
Bearableness of depression is measured with a visual
analogue scale (VAS) ranging from 0 (very unbearable)
to 100 (very well bearable). Anxiety is measured by the
Beck Anxiety Inventory (BAI), a 21-item multiple-choice
self report inventory that measures the severity of gener-
alized anxiety and panic symptoms in adults and adoles-
cents [41].
Pain complaints are evaluated with the Graded
Chronic Pain Scale (GCPS) [42], a 7-item scale measur-
ing aspects of pain, physical ability and social interfer-
ence, resulting in a 5-class hierarchical scale ranging
from 0 (no pain problem) to IV (high disability/severely
limiting). Next to the GCPS, bearableness of pain is
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evaluated with a VAS-scale ranging from 0 (very
unbearable) to 100 (very well bearable).
Other secondary outcomes are disability during the
last 30-days associated with both physical and mental
problems and is measured by a shortened version of the
World Health Organisation - Disability Assessment
Schedule II (WHO-DAS-II) [43], resulting in a disability
score ranging from 0-100 with a higher score reflecting
greater disability. Quality of life data are collected using
the EQ5D [44], a standardized instrument for describing
and valuing health related quality of life.
Subjective health is evaluated by a visual analogue
scale ranging from 0 (the worst imaginable health condi-
tion) to 100 (the best imaginable health condition).
Health care use and work productivity are evaluated
by the Trimbos/iMTA Questionnaire for Costs asso-
ciated with Psychiatric Illness (TIC-P), a 29-item list
which focuses on establishing costs related to loss of
productivity at work and health care utilization [45].
Variables expected to modify the effect of the inter-
vention Personality, as a possible effect modifier, is mea-
sured at baseline by the NEO-PI-R, a 60-item validated
questionnaire measuring the five domains of personality
including neuroticism, extraversion, agreeableness, con-
scientiousness and openness to experience [46].
Confounders: Lifestyle behaviours Self-reported level of
physical activity is assessed by means of the validated
Short QUestionnaire to ASsess Health enhancing physi-
cal activity (SQUASH), a 12-item questionnaire which
evaluates the frequency and duration of physical activ-
ities in the domains of work, domestic and leisure time
[47]. Tobacco and alcohol intake is measured with a
standard single question on the frequency of use per
day.
Additional measures in the intervention group
The Profile of Mood States (POMS) registers partici-
pants’ mood after a running session for in total three
times during the intervention period (at the beginning,
halfway and at the end). The Dutch shortened version
of the POMS [48] consists of 32 items divided over
seven subscales including tension, depression, anger,
fatigue, vigour, positive and negative affect.
At regular intervals participants score their exertion
on a Borg-scale ranging from 6 (very, very light) to 20
(very, very severe) [49]. At the end of the intervention
period, or when participants dropped out of the RT or
NW therapy, a short questionnaire is administered eval-
uating their satisfaction and experience with the
intervention.
Randomisation, blinding and treatment allocation
Randomisation takes place at every location separately.
This way, every location will have an equal distribution
of participants between the intervention and control
group. The SPSS random generator (SPSS version 14.0)
[50] will be used to allocate patients. Ten closed envel-
opes with allocation numbers are presented to the parti-
cipants. They choose an envelope, after which the
research assistant tells the patients in which arm of the
study they are included. Evaluators of the main outcome
measure (HRSD) are blinded for group allocation and
are trained regularly for inter-rater reliability. All other
measures will be evaluated by a research assistant, who
is not blinded for group allocation.
Exercise intervention
The exercise sessions will take place twice a week (40
sessions in total): once a week a supervised group ses-
sion is offered and once a week the patient does an
individual training, with clear instructions beforehand
and an evaluation at the beginning of the next super-
vised session. Each supervised session, in which the
trainers are working according to a standardized proto-
col, lasts one hour, of which 30 min are spent running
(RT)/Nordic walking (NW). The remaining time is
spent on warming-up and cooling-down. Each patient
follows an individualised intervention protocol with a
gradually increasing training intensity. The goal is to
achieve a 30 min period of continuous running in the
last sessions (two times a week 30 min continuous
aerobic exercise at least 60% of the maximal heart
rate). The NW program follows a comparable progres-
sive schedule with increased time spent Nordic walking
with high intensity.
Intensity in RT as in NW is monitored by the instruc-
tor during every supervised session by counting the
heart rate and three times during the intervention per-
iod by electronic registration (Polar RS 400, Electro Oy,
Finland). The control group receives usual care for
depression in accordance with the revised Dutch guide-
line [51] and are advised to exercise regularly. Hospita-
lised and day-care patients in the control group are
supposed not to participate in organised high intensity
aerobic exercise during the intervention period. Only
low-intensity activity psycho-motor therapy is allowed.
Compliance and withdrawal
In order to improve compliance during the intervention
period, a protocol will be followed concerning missed
exercise therapy sessions by participants. This protocol
includes: 1) active approach by the exercise instructor in
case of no show, and 2) encouragement of other partici-
pants to contact each other in case of no show. Partici-
pants can withdraw at any time for any reason without
any consequences. Also, the investigator can decide to
withdraw a participant from the study for urgent medi-
cal reasons. Participants who withdraw from the inter-
vention will be asked the reason(s) for drop-out but will
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be retained in the study for the intention to treat
analysis.
Statistical analyses
Comparability of the intervention and control groups
will be examined for the baseline measurements. If
necessary, analyses will be adjusted for baseline differ-
ences. The primary analysis of the data set will be
according to the ‘intention to treat’ principle. A second-
ary ‘per protocol’ analysis will be done taking into
account the level of compliance and the amount of exer-
cise during the intervention period. Usual daily physical
activity, tobacco smoking and alcohol intake will be
treated as confounders.
Differences in remission rates (and other categorical
outcomes) between the experimental groups are exam-
ined by contingency table Chi-square statistics. Differ-
ences in mean scores on continuous outcomes (e.g.
HRSD) between the intervention groups are examined
by analysis-of-variance.
Ethical principles and safety
The study has been designed and will be carried out in
accordance with the principles of the Helsinki Declara-
tion (Edinburgh, Scotland Amendment, October 2000).
The study protocol has been approved by the Medical
ethical committee for mental health (Metigg Kamer
Noord).
Discussion
The aim of this study is to investigate the effectiveness
of aerobic exercise therapy (RT or NW) on depression
in adult patients in addition to usual care. Also, the
effect of physical exercise on frequently existing co-mor-
bid diseases or risk factors for such disorders as meta-
bolic syndrome is an objective of this study.
This is the first well conducted add-on randomised
controlled high-quality trial into the effect of aerobic
exercise on depression with a correct randomisation
procedure, blinded outcome assessment, intention to
treat analysis, study into cost-effectiveness, quality of life
and long-term follow-up as was advised in earlier publi-
cations. EFFORT-D can therefore contribute to stronger
evidence for this type of intervention, which can result
in more specified recommendations for clinical practice.
Another strength of this study is the fact that also
severely clinically depressed patients, who are mostly
excluded in other studies, will be included. A relatively
greater effect of exercise in this subgroup of severely
depressed patients is possible. A challenge of the study
lies in the motivational techniques needed to exercise
with depressed patients, which is proven to be difficult
[52] and it will take a serious effort not to exceed the
calculated 30% drop-out patients in the intervention
group. Because this study is supported by a strong
hypothesis and minimal negative side effects are
expected, one-tailed statistical analysis is also possible if
the large number of included participants can’t be
reached within the planned time. Furthermore, the
diversity of outcome measures makes it possible to dis-
tinguish more explicitly those depressed patients that
could benefit most from exercise.
Acknowledgements
The former “Open Ankh Foundation” (since March 2008 “Zorgcoöperatie
Nederland”) funded part of this project, together with the Symfora Group of
Mental Hospitals (January 2010 “GGZ Centraal”), and TNO (Netherlands
Organisation for Applied Scientific Research).
The authors would also like to thank Professor B.W. Penninx and Professor E.
de Geus for their contribution in the design discussion and
recommendations for biometric diagnostics.
Author details
1GGZ Centraal Centers for Mental Health, Symfora-Meander Centre for
Psychiatry, Utrechtseweg 266, 3800 DB Amersfoort, The Netherlands. 2TNO
Expert Center Life Style, Wassenaarseweg 56, 2333 AL Leiden, The
Netherlands. 3Body@Work, Research Center Physical Activity, Work and
Health, TNO-VUmc, Van der Boechhorststraat 7, 1081 BT Amsterdam, The
Netherlands. 4Department of Psychiatry, VU University Medical Centre, A.J.
Ernststraat 887, 1081 HL Amsterdam, The Netherlands. 5The EMGO Institute
for Health and Care Research (EMGO+), VU University Medical Centre, Van
der Boechhorststraat 7, 1081 BT Amsterdam, The Netherlands.
Authors’ contributions
FRK is principle investigator, psychiatrist and project leader of the project in
GGZ Centraal and Symfora-Meander Hospitals and drafted the manuscript,
IH is project leader for the study at Body@Work, designed the study and has
been involved in drafting the manuscript, ET was involved in the study
design, organizing the data and commented the manuscript, AJB was
involved in the study design and revised the manuscript critically and gave
approval for publication, MHR was involved in the study design, revised the
manuscript critically and gave final approval of the version to be published.
Competing interests
The authors declare that they have no competing interests.
Received: 20 December 2011 Accepted: 19 January 2012
Published: 19 January 2012
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Pre-publication history
The pre-publication history for this paper can be accessed here:
http://www.biomedcentral.com/1471-2458/12/50/prepub
doi:10.1186/1471-2458-12-50
Cite this article as: Kruisdijk et al.: Effect of running therapy on
depression (EFFORT-D). Design of a randomised controlled trial in adult
patients [ISRCTN 1894]. BMC Public Health 2012 12:50.
Kruisdijk et al. BMC Public Health 2012, 12:50
http://www.biomedcentral.com/1471-2458/12/50
Page 9 of 9

Effect of running therapy on depression (EFFORT-D). Design of a randomised controlled trial in adult patients [ISRCTN 1894].
Kruisdijk, Frank R,Hendriksen, Ingrid J M,Tak, Erwin C P M,Beekman, Aartjan T F,Hopman-Rock, Marijke