Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000 Ghent, Belgium
Centre for Sport and Exercise Research, Staffordshire University, Leek Road, Stoke-on-Trent, Staffordshire ST4 2DF, UK
Nutritional Epidemiology Unit, UMR INSERM U557/INRA U1125/CNAM/University Paris 13, CRNH IdF, 93017 Bobigny, France
Department of Nutrition, Pitie-Salpetriere Hospital (AP-HP), University Pierre et Marie Curie-Paris6, CRNH IdF, 75013 Paris, France
Institute of Sports Science, University of Graz, Mozartgasse 14, 8010 Graz, Austria
Department of Public Health, University of Oxford, Old Road Campus, Headington, Oxford OX3 7LF, UK
National Obesity Observatory, 4150 Chancellor Court, Oxford OX4 2GX, UK
Urho Kaleva Kekkonen Institute for Health Promotion Research, FIN-33500 Tampere, Finland
Karolinska Institute, Department of Biosciences, Preventive Nutrition, Novum, 141 57 Huddinge, Sweden
Abstract
Background
A questionnaire to assess physical activity related environmental factors in the European population (a 49-item and an 11-item version) was created as part of the framework of the EU-funded project "Instruments for Assessing Levels of PHysical Activity and fitness (ALPHA)". This paper reports on the development and assessment of the questionnaire's test-retest stability, predictive validity, and applicability to European adults.
Methods
The first pilot test was conducted in Belgium, France and the UK. In total 190 adults completed both forms of the ALPHA questionnaire twice with a one-week interval. Physical activity was concurrently measured (i) by administration of the long version of the International Physical Activity Questionnaire (IPAQ) by interview and (ii) by accelerometry (Actigraph™ device). After adaptations, the second field test took place in Belgium, the UK and Austria; 166 adults completed the adapted questionnaire at two time points, with minimum one-week interval. In both field studies intraclass correlation coefficients (ICC) and proportion of agreement were computed to assess the stability of the two test scores. Predictive validity was examined in the first field test by correlating the results of the questionnaires with physical activity data from accelerometry and long IPAQ-last 7 days.
Results
The reliability scores of the ALPHA questionnaire were moderate-to good in the first field testing (ICC range 0.66 - 0.86) and good in the second field testing (ICC range 0.71 - 0.87). The proportion of agreement for the ALPHA short increased significantly from the first (range 50 - 83%) to the second field testing (range 85 - 95%). Environmental scales from both versions of the ALPHA questionnaire were significantly associated with self-reported minutes of transport-related walking, and objectively measured low intensity physical activity levels, particularly in women. Both versions were easily administered with an average completion time of six minutes for the 49-item version and less than two minutes for the short version.
Conclusion
The ALPHA questionnaire is an instrument to measure environmental perceptions in relation to physical activity. It appears to have good reliability and predictive validity. The questionnaire is now available to other researchers to investigate its usefulness and applicability across Europe.
Background
Until recently, physical activity promotion research has focused on individual factors (demographics and psychosocial determinants). There is now growing agreement among researchers that the physical or built environment may play an important role as well
However, until now, evidence of the predictive relationship between environmental determinants and physical activity is not very consistent. Wendel-Vos and colleagues found in their review of 47 papers
One of the challenges of this new research domain is how to measure attributes of the built environment associated with physical activity in a valid, reliable and feasible way. Studies of the physical environment and physical activity have typically used two types of exposure measures: (i) measures of perceptions of the environment using questionnaires; (ii) objective measures of the environment derived from observations of the environment (audits, ground truthing) or through spatial Geographic Information Systems (GIS) data
Early measures of perceptions of the environment were criticised for their lack of metric data (e.g. repeatability, face validity)
One objective of the EU-funded Instruments for Assessing Levels of Physical Activity and Fitness (ALPHA) project, is to propose standardised instruments for physical activity and fitness monitoring across Europe
Methods
The reliability and validity testing were undertaken in four phases, translation, cognitive testing, and two iterations of field testing. First of all the original version of the ALPHA questionnaire was translated into Dutch, French, and German, followed by cognitive testing. Next a first field test was conducted in three countries. An expert meeting was organised to discuss the results before a second smaller field test was conducted to assess the modified questionnaire.
Translation and cognitive testing
The English questionnaire (the source) was translated into Dutch, French and German using a standard protocol based on the guidelines of Eurostat
After the translation process, cognitive testing was conducted using cognitive interviewing
Through the cognitive testing process, questions that were not clear or comprehensive were identified, discussed with the research team and rephrased.
Field testing I
Participants and procedures
Participants were recruited in three countries (Belgium, UK and France) between October 2008 and January 2009. To ensure some variance in the measured characteristics (e.g. population density), the participants within each country were derived from distinct areas (and thus different built environments). In Belgium a random sample in three different neighbourhoods (town, outskirts of town and village/countryside) was drawn. In each neighbourhood, letters with information about the study were distributed by post. One week after mailing the information letter, potential participants were visited at home and asked if they would participate. In the UK, participants randomly selected from 10 areas of an English city for a previous study
To assess test-retest stability, participants completed, in the presence of a researcher, both forms of the ALPHA questionnaire twice, with an interval of one to two weeks. This is a standard time frame in test-retest studies as it is long enough so that respondents are unlikely to remember their answers to the first testing, but short enough to minimise potential changes in physical activity behaviour. To avoid order effects, participants in each study centre were randomly assigned into two groups: Group 1 completed the short version of the questionnaire first (at first and second assessment), followed by the 49-item version, and Group 2 completed the 49-item version first (at first and second assessment), followed by the short version.
To assess predictive validity, physical activity behaviour was measured by accelerometry and long International Physical Activity Questionnaire (IPAQ) last 7 days. Participants were asked to wear accelerometers on the hip during all waking hours for 7 consecutive days following the first visit. Accelerometer recordings were collected at the second visit at which time the researcher interview-administered the Long IPAQ last 7 day. The interview version was preferred to the self-administered version of the IPAQ because of the tendency towards over reporting of physical activity that has been previously reported
Measures
The development of the initial ALPHA environmental questionnaire has been described elsewhere
Self-reported physical activity level was assessed by the Long IPAQ last 7 day
The MTI Actigraph accelerometer model 7164 was used in Belgium and France, and the Actigraph GT1M was used in the UK. In all cases an epoch time of one minute was used to provide an objective measure of habitual physical activity (over 7 days).
Finally, participants were asked to provide information on their age, height, weight, sex, ethnicity, living situation, educational attainment, occupational status and living environment.
Data reduction
Adverse items of the environmental questionnaire were recoded and sum scores for each scale were calculated.
For the long IPAQ last 7 day, each activity was expressed in minutes/week by multiplying frequency (day/week) and duration (minutes/day) of the activity. Indices of each domain were calculated by summing all physical activities undertaken for each specific context (work, domestic, transport and leisure). A 'total moderate-intensity and vigorous-intensity physical activity' index was computed by summing all reported physical activities undertaken at moderate and vigorous intensity across the four domains.
Accelerometer data were downloaded by placing the accelerometer into a reader interface unit (RIU) and using specific software (RIU256.exe)
Statistical analysis
Cronbach alphas were calculated to assess the internal consistency of each scale of the environmental questionnaire; results >0.70 were considered good
Pearson correlations between environmental variables (sum scores) and accelerometer data, and between environmental variables and IPAQ measurements, were calculated to assess predictive validity.
All analyses were performed using SPSS 15.0 software (SPSS Inc., Chicago, IL, USA).
International expert meeting
After the first field testing an international expert meeting in February 2009 was organised to discuss the results (a list of all experts can be found in additional file
International expert group. List of the members of the international expert group.
Click here for file
Field testing II
Participants and procedures
For the second and smaller field testing a new sample was recruited in three countries (Belgium, UK and Austria) between April and May 2009 using the same inclusion criteria as in the first field testing. In Belgium a random sample in three different neighbourhoods (town, outskirts of town, and village/countryside - all different from those in the first field testing) was recruited using the same approach as used in the first field testing. In the UK and Austria, convenience samples comprised university colleagues, students and other associates participated. The final sample consisted of 166 participants, 60 from Belgium, 57 from the UK and 49 from Austria.
In this second round of testing only test-retest stability was assessed for both versions, in a similar way to the first field testing.
Measures
An adapted version of the ALPHA environmental questionnaire was used. This instrument can be found in additional file
ALPHA questionnaire. ALPHA measure of environmental perceptions: active travel and physical activity. For different languages and a manual see also
Click here for file
ALPHA questionnaire (short form). ALPHA short measure of environmental perceptions: active travel and physical activity.
Click here for file
Adaptations. Adaptations of ALPHA and ALPHA short, made after the first field testing and second expert meeting
Click here for file
Data reduction and statistical analysis
Adverse items of the environmental questionnaire were recoded and sum scores for each scale were made. Cronbach alphas were calculated to assess the internal consistency of each scale of the environmental questionnaire. Intraclass correlation coefficients (sum scores or items on 5 point scales) and proportion of agreement (separate items) were used to compute the coefficient of stability of the scores on the two tests.
Results
Field testing I
Most participants in the first field testing were female (63%); most participants lived in an urban area (86.3%) and were employed (78.9%). Average age was 40 years and average BMI 25 kg/m2 (see Table
Characteristics of the participants in the first and second field testing
First field testing N = 190
Second field testing N = 166
Age (years)
40.52 ± 12.46
32.89 ± 12.89
BMI (kg/m2)
25.19 ± 4.37
23.94 ± 3.56
N
%
N
%
Sex
Male
71
37.4
88
53
Female
119
62.6
78
47
Nationality
Belgian
60
31.6
58
35.2
British
66
34.7
56
33.9
French
64
33.7
-
-
Austrian
-
-
49
29.7
Living situation
with partner and children
69
36.3
53
31.9
with partner
46
24.2
37
22.3
with children
20
10.5
2
1.2
with parents
30
15.8
34
20.5
Alone
25
13.2
26
15.7
with friends/other
-
14
8.4
Higher education
Yes
95
50
135
81.3
No
95
50
31
18.7
Having a job
Yes
150
78.9
98
59.4
No
40
21.1
67
40.6
NS-SEC
Managerial and professional occupations
40
24.5
23
23.5
Intermediate occupations
84
51.5
65
66.3
Routine and manual occupations
39
23.9
10
10.2
Place of residence
Town
103
54.2
77
46.4
Outskirts of the town
61
32.1
51
30.7
Village/Countryside
26
13.7
38
22.9
NS-SEC: National Statistics Socio-economic Classification
Feasibility
Mean (±SD) time for questionnaire completion during the first assessment was 6 minutes 47 seconds (±2 min) for the 49-item version and 1 minute and 46 seconds (±39 seconds) for the short version.
Test-retest reliability
Table
First field testing of the ALPHA questionnaire (N = 190): Answer frequencies, mean scores, and test-retest reliability scores.
Answer Frequencies and mean score of each item on the first assessment
Test-retest reliability scores
Types of residences
Item/scale
None
A Few
Some
Most
All
Mean (SD)
Agreement, %
ICC
1. Residential density
0.68a
a) Detached houses
19.5
31.1
22.6
18.4
8.4
2.7 (1.2)
70
0.80
b) Semi-detached townhouses, terraced houses
8.5
29.6
19.6
37.6
4.8
3.0 (1.1)
66
0.71
c) Flats of 6 floors or more
43.0
24.7
15.1
12.9
4.3
2.1 (1.2)
66
0.72
Travel time to facilities
1-5 min
6-10 min
11-20 min
21-30 min
>30 min
Mean (SD)
Agreement, %
ICC
2. Distance to local facilities
0.86 b
a) Local shop
64.7
25.8
7.9
0.5
1.1
1.5 (0.8)
76
0.74
b) Supermarket
20.5
24.7
26.3
9.5
8.9
2.5 (1.2)
67
0.78
c) Local services
20.6
31.2
30.2
11.1
6.9
2.5 (1.1)
66
0.80
d) Restaurant
46.8
27.9
16.8
3.2
5.3
1.9 (1.1)
62
0.71
e) Fast-food restaurant
27.4
25.3
16.3
14.2
16.8
2.7 (1.4)
65
0.82
f) Busstop
74.2
17.4
6.8
0.5
1.1
1.4 (0.7)
81
0.75
g) Sport and leisure facility
16.3
25.3
28.9
14.2
15.3
2.9 (1.3)
63
0.70
h) Open recreation area
37.4
24.2
23.2
8.4
6.8
2.2 (1.2)
59
0.73
Acceptance of statements
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
I don't know
Mean (SD)
Agreement, %
ICC
3. Total Infrastructure
0.68 b
Cycling Infrastructure,
0.67 c
Walking infrastructure
0.66 d
a) special lanes, routes or paths to cycle
18.4
13.7
37.9
28.9
1.1
2.8 (1.1)#
64
0.75
b) traffic-free cycle routes
41.6
24.2
19.5
12.6
2.1
2.0 (1.1) #
59
0.60
c) sidewalks
2.6
5.8
18.4
72.6
0.5
3.6 (0.7) #
71
0.60
d) pedestrian zones for shopping
55.3
11.6
16.8
14.7
1.6
1.9 (1.2) #
64
0.69
4. Maintenance
0.66b
a) cycling paths are well maintained
9.5
10.1
39.7
20.6
20.7
2.9 (0.9) #
60
0.61
b) sidewalks are well maintained
5.3
18.5
56.1
19.0
1.1
2.9 (0.8) #
65
0.58
c) public recreation facilities are well maintained
5.3
9.5
47.1
32.8
5.3
3.1 (0.8) #
62
0.61
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
Mean (SD)
Agreement, %
ICC
5. Safety
0.75b
Safety from crime
0.77e
Safety from traffic
0.69f
a) not safe to leave a bicycle locked
16.5
28.7
33.5
21.3
2.6 (1.0)
53
0.53
b) not enough safe places to cross busy streets
18.0
46.0
31.2
4.8
2.2 (0.8)
52
0.44
c) Walking is unsafe because of the traffic
35.4
50.3
12.7
1.6
1.8 (0.9)
64
0.54
d) Cycling is unsafe because of the traffic
20.6
44.4
27.5
7.4
2.2 (0.9)
61
0.64
e) unsafe during the day because of the level of crime
58.2
31.7
9.0
1.1
1.5 (0.7)
71
0.61
f) unsafe during the night because of the level of crime
37.0
32.8
22.2
7.9
2.0 (1.0)
68
0.81
6. Pleasant
0.81b
Aesthetics
0.79g
a) a pleasant environment for walking and cycling
2.1
21.6
52.6
23.7
2.9 (0.7)
69
0.70
b) generally free from litter or graffiti
10.5
29.5
43.7
16.3
2.7 (0.9)
66
0.61
c) trees along the streets
12.6
16.8
33.7
36.8
2.9 (1.0)
62
0.73
d) a lot of badly maintained, unoccupied or ugly buildings
38.4
35.8
20.5
5.3
1.9 (0.9)
66
0.65
7. Cycling & walking network
0.80b
Connectivity
0.92h
a) Cycling is quicker than driving during the day
20.0
28.4
27.9
15.3
8.4
2.4 (1.0) #
53
0.57
b) Easier to take shortcuts with a bicycle or walking that with a car
10.5
16.3
41.6
27.9
3.7
2.9(0.9) #
57
0.52
c) many intersections
5.3
21.6
43.7
26.3
3.2
2.9 (0.8) #
60
0.61
d) many different routes for cycling or walking from place to place
2.1
23.2
48.9
22.6
3.2
3.0 (0.7) #
66
0.65
Availability of
Agreement, %
ICC
yes
no
8. Home environment
0.86b
a) Bicycle
61.1
38.9
99
b) Garden
72.0
28.0
96
c) Small sports equipment
70.0
30.0
94
d) Eercise equipment
47.9
52.1
93
e) Car
82.1
17.9
98
f) Dog
24.7
75.3
99
9. Workplace or study environment
0.82b
a) Escalators
61.0
39.0
91
b) Stairs
89.9
10.1
94
c) Fitness centre/equipment
27.7
72.3
93
d) Bicycles provided by employer or school
13.8
86.2
93
e) A safe place to leave a bike
66.5
33.5
85
f) A free car park
65.4
34.6
90
g) Showers and changing rooms
57.9
42.1
92
h) Exercise classes
22.6
77.4
92
i) Sports club
22.0
48.0
92
j) Employer subsidised public transport/cycling
44.7
55.3
85
# without 'I don't know' variable
a weighted by the following formula = item1a + (12* item 1b)+ (50*item 1c); b: total sum score of all items; c: sum score of items 3a & 3b; d: sum score of items 3c & 3d; e: sum score of reversed items 5a, 5e & 5f; f: sum score of reversed items 5b, 5c, 5d; g:sum score of items 6b, 6c, reversed 6d; h:sum score of items 7b, 7c & 7d
Table
First field testing of the ALPHA short (N = 190): Answer frequencies, mean scores, and test-retest reliability scores.
Answer Frequencies and mean score of each item on the first assessment
Test-retest reliability scores
Item/scale
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
I don't know
Mean (SD)
Agreement, %
ICC
Total
0.75a
A. Most of the houses in my neighbourhood are detached houses
35.8
22.6
24.2
17.4
2.2 (1.1)
66
0.80
B. Many shops, stores, markets or other places to buy things I need are within easy walking distance of my home
4.2
14.2
33.2
48.4
3.9 (0.9)
69
0.64
C. There is a transit stop (such as bus stop, train, trolley or tram station) within easy walking distance of my home
1.6
3.7
15.8
78.9
3.7 (0.6)
83
0.57
D. There is an open recreation area (e.g. park, beach or other open space) within easy walking distance of my home
3.2
11.6
25.3
60.0
3.4 (0.8)
70
0.64
E. There are many different routes for cycling or walking from place to place in my neighbourhood so I don't have to go the same way every time
3.7
18.5
41.3
36.5
3.1 (0.8)
64
0.63
F. Walking and cycling are unsafe because of the traffic in my neighbourhood
19.5
44.2
30.5
5.8
2.2 (0.8)
56
0.51
G. Walking and cycling are unsafe because of the level of crime in my neighbourhood
43.2
40.5
12.1
4.2
1.8 (0.8)
66
0.50
H. My local neighbourhood is a pleasant environment for walking and cycling
3.7
26.3
46.8
26.8
3.0 (0.8)
64
0.57
I. I have access to exercise and sports equipment at home e.g. weights, racquets, skis for personal use
32.1
15.8
22.6
29.5
2.5 (1.2)
61
0.71
J. My workplace provides facilities to support me walking or cycling to work e.g. changing rooms, bike storage
25.3
14.7
23.7
22.1
14.2
2.5
(1.2)#
50
0.58
K. I have access to exercise and sports facilities at work e.g. fitness centre/equipment, stairs
38.1
15.9
16.9
15.3
13.8
2.1 (1.1) #
59
0.69
#without "not applicable"; a: total sum score of all items
Predictive validity
Tables
First field testing (N = 190): Pearson correlations between the ALPHA questionnaire and ALPHA short with long last 7 day IPAQ, stratified by sex (only statistically significant values are shown).
ALPHA & IPAQ
Name of the scale (number of items in the questionnaire)
Sex a
Total PA
MVPA
Walking for transport
Cycling for transport
Total transport
Total walking
Leisure time PA
Home PA
Density score (1a, 1b, 1c)
Male
Female
0.20*
0.21*
Distance to local facilities (2a to 2h)
Male
-
-0.33**
-0.32**
Female
0.25*
-0.20*
Availability of sidewalks (3c, 3d)
Male
0.32*
Female
-0.20*
-0.19*
Maintenance (4a, 4b, 4c, 4d)
Male
0.30*
Female
Safety from traffic (reversed 5b, 5c, 5d)
Male
Female
-0.31**
-0.30**
-0.22*
0.22*
Aesthetics (6b, 6c, 6d)
Male
Female
0.19*
-0.25**
-0.23*
Cycling and walking network (7a, 7d)
Male
0.24*
Female
Connectivity (7b, 7c, 7d)
Male
0.28*
Female
Home environment (8a to 8f)
Male
0.38**
Female
0.20*
Workplace or study environment (9a to 9j)
Male
0.33**
0.25*
0.34**
Female
ALPHA short & IPAQ
Total sum of 11 items
Male
0.34**
0.25*
Female
0.21*
a men: N = 70, women: N = 120
Total_PA: total minutes PA/week (low, moderate, vigorous in all domains); MVPA:total minutes PA/week at moderate to vigorous intensity; walking for transport: total minutes transport-related walking/week; Cycling for transport: total minutes transport-related cycling/week; Total transport: total minutes PA/week by active transportation (walking and/or cycling for transport); Total walking: total minutes walking/week (job, transport, leisure time); Leisure time PA:total minutes PA/week in leisure time; Home PA: total minutes PA/week in and around the house (inclusive gardening); * p < 0.05; ** p < 0.01
First field testing (N = 190): Pearson correlations between ALPHA and ALPHA short questionnaire with accelerometer, stratified by sex (only statistically significant values are shown).
Name of the scale (number of items in the questionnaire)
Sex a
Total PA
VPA
MVPA
LPA
Density score (1a, 1b, 1c)
Male
Female
Distance to local facilities (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h)
Male
Female
Availability of sidewalks (3c, 3d)
Male
Female
Maintenance (4a, 4b, 4c, 4d)
Male
Female
Safety from traffic (reversed 5b, 5c, 5d)
Male
Female
0.20*
Aesthetics (6b, 6c, 6d)
Male
Female
0.25*
0.26*
Cycling and walking network (7a, 7d)
Male
Female
0.28**
0.29
Connectivity (7b, 7c, 7d)
Male
Female
0.24*
Home environment (8a, 8b, 8c, 8d, 8e, 8f)
Male
Female
0.21*
0.21*
Workplace or study environment (9a, 9b, 9c, 9d, 9e, 9f, 9h, 9i, 9j)
Male
0.32*
Female
0.34**
0.32**
ALPHA short & accelerometer
Total sum of 11 items
Male
0.29*
Female
0.26**
0.28**
0.28*
a men: N = 65: women: N = 106
Total_PA: total minutes PA/week (low, moderate, vigorous in all domains); VPA: total minutes PA/week at vigorous intensity (>5724 counts per minute); MVPA:total minutes PA/week at moderate to vigorous intensity (>1951 counts per minute); LPA: total minutes PA/week at low intensity (below 1952 counts per minute); * p < 0.05; ** p < 0.01
All significant correlations were in the hypothesised directions (higher environmental support of physically activity was correlated with higher levels of physically activity) except for the negative correlations found between the scales 'availability of sidewalks' and 'safety from traffic' with some IPAQ variables. The size of all correlations ranged from 0.19-0.38 which is an indication of moderate validity. Environmental scales of ALPHA were mostly significantly correlated with minutes of transport-related walking as measured with the IPAQ, both in men and women. Very few significant correlations were found with accelerometers in men, however there were several significant correlations found in women, especially with physical activity at low intensity.
The sum score calculated from the ALPHA short was significantly correlated with both IPAQ and accelerometers in men and women. All significant correlations were in the expected directions and ranged from 0.21-0.34.
International expert meeting
Based on the results of the first field testing wording and answer categories of specific items with lower reliability scores were modified following discussions at the expert meeting (see Additional file
Field testing II
In the second field testing almost half (47%) of the participants were female. Most of the participants lived in an urban area (77.1%), and were employed (59%), with an average age of 33 years and an average BMI of 24 kg/m2 (see Table
Internal consistency
Cronbach alphas ranged from 0.65-0.82 except for the pleasant environment scale (alpha = 0.34) (data not shown).
Test-retest reliability
Answer frequencies and mean scores for each item on the first assessment of the ALPHA questionnaire and their test-retest reliability scores are shown in Table
Second field testing of the ALPHA questionnaire (N = 166): Answer frequencies; mean scores and its test-retest reliability scores.
Answer Frequencies and mean score of each item on the first assessment
Test-retest reliability scores
Item/scale
None
A Few
Some
Most
All
Mean (SD)
Agreement %
ICC
1. Residential density
0.80a
a) Detached houses
18.5
27.8
27.8
22.2
3.7
2.65 (1.1)
77
0.81
b) Semi-detached houses or terraced houses
3.7
15.2
39.0
39.0
3.0
3.23 (0.9)
59
0.56
c) Apartment buildings or blocks of flats
22.0
37.8
27.4
11.6
1.2
2.32 (1.0)
73
0.80
Travel time to facilities
1-5 min
6-10 min
11-20 min
21-30 min
>30 min
Mean (SD)
Agreement %
ICC
2. Distance to local facilities
0.87b
a) Local shop
57.2
22.9
13.9
3.0
3.0
1.7 (1.0)
75
0.80
b) Supermarket
43.0
24.2
20.6
5.5
6.7
2.1 (1.2)
75
0.82
c) Local services
30.7
29.5
21.7
12.0
6.0
2.3 (1.2)
67
0.77
d) Restaurant, café, pub..
50.0
30.1
12.0
4.8
3.0
1.8 (1.0)
75
0.72
e) Fast-food restaurant
36.2
23.3
13.8
12.1
14.7
2.5 (1.5)
60
0.87
f) Bus stop
72.7
17.6
5.5
3.0
1.2
1.4 (0.8)
79
0.74
g) Sport and leisure facility
18.7
29.5
27.7
11.4
12.7
2.7 (1.2)
65
0.75
h) Open recreation area
48.5
27.9
10.3
6.1
7.3
3.5 (0.8)
76
0.76
Acceptance of statements
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
Mean (SD)
Agreement %
ICC
3. Infrastructure
0.79b
Pedestrian infrastructure
0.75c
Cycling infrastructure
0.74d
a) Sidewalks
4.8
7.8
17.5
69.9
3.5 (0.8)
73
0.74
b) pedestrian zones or pedestrian trails
24.7
23.5
28.9
22.9
2.5 (1.1)
59
0.65
c) Special lanes, routes or paths for cycling
18.8
17.0
33.9
30.3
2.8 (1.1)
62
0.69
d) cycle routes separated from traffic
26.7
24.2
28.5
20.6
2.4 (1.1)
61
0.68
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
Not applicable
Mean (SD)
Agreement %
ICC
4. Maintenance
0.74#
a) sidewalks are well maintained
7.9
13.4
42.1
35.4
1.2
3.1 (0.9
57
0.60#
b) cycling paths are well maintained
15.3
13.5
40.5
23.9
6.7
2.8 (1.0)
63
0.55#
c) Play areas, playgrounds, parks or other open spaces are well maintained
3.1
11.7
47.2
35.0
3.1
3.2 (0.8)
66
0.62#
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
Mean (SD)
Agreement %
ICC
5. Safety
0.71 b
Safety from crime
0.78 e
Safety from traffic
0.68 f
a) dangerous to leave a bicycle locked
28.5
40.0
20.6
10.9
2.1 (1.0)
66
0.69
b) not enough safe places to cross busy streets
41.2
37.0
18.2
3.6
1.8 (0.8)
61
0.57
c) Walking is dangerous because of the traffic
47.3
40.6
10.3
1.8
1.7 (0.7)
68
0.58
d) Cycling is dangerous because of the traffic
35.8
37.0
24.2
3.0
2.0 (0.9)
62
0.61
e) dangerous during the day because of the level of crime
73.9
23.0
2.4
0.6
1.3 (0.5)
74
0.57
f) dangerous during the night because of the level of crime
43.1
44.0
8.6
4.3
1.7 (0.8)
69
0.60
6. Pleasant
0.84 b
Aesthetics
0.74 g
a) a pleasant environment for walking and cycling
3.6
19.3
45.2
31.9
3.1 (0.8)
68
0.65
None
A few
Some
Plenty
Mean (SD)
Agreement %
ICC
b) litter or graffiti
36.7
34.9
20.5
7.8
2.0 (0.9)
71
0.82
c) trees along the streets
15.1
18.7
37.3
28.9
2.8 (1.0)
66
0.72
d) badly maintained, unoccupied or ugly buildings
40.6
44.2
9.7
5.5
1.8 (0.8)
68
0.57
Strongly disagree
Somewhat disagree
Somewhat agree
Strongly agree
Mean (SD)
Agreement %
ICC
7. Cycling and walking network
0.84 b
Connectivity
0.91h
a) Many shortcuts for walking
6.0
27.7
47.0
19.3
2.8 (0.8)
67
0.58
b) Cycling is quicker than driving during the day
19.9
31.9
25.9
22.3
2.5 (1.0)
67
0.79
c) many road junctions
7.2
35.5
39.8
17.5
2.7 (0.8)
61
0.61
d) many different routes for cycling or walking from place to place
3.6
19.3
56.0
21.9
2.9 (0.7)
63
0.54
Availability of
yes
no
Agreement %
ICC
8. Home environment
0.72 b
a) Bicycle
81.3
18.7
99
b) Garden
76.5
23.5
95
c) Small sports equipment
86.7
13.3
94
d) Exercise equipment
60.2
39.2
96
e) Car
86.1
13.3
98
f) Dog
19.3
80.1
98
9. Workplace or study environment
0.83 b
a) Escalators
47.4
52.6
91
b) Stairs
89.5
10.5
95
c) Fitness centre/equipment
34.9
65.1
91
d) Bicycles provided by employer or school
19.9
80.1
91
e) A safe place to leave a bike
74.2
25.8
87
f) Enough car parking spaces
56.3
43.7
93
g) Showers and changing rooms
62.9
37.1
93
h) Exercise classes
39.1
60.9
91
i) Sports club
38.4
61.6
89
j) Employer subsidised public transport
48.3
51.7
87
# without not applicable
ICC = Intraclass correlation coefficient
a weighted by the following formula = item1a + (12* item 1b)+ (50*item 1c); b: total sum score of all items; c: sum score of items 3a & 3b; d: sum score of items 3c & 3d; e: sum score of reversed items 5a, 5e & 5f; f: sum score of reversed items 5b, 5c, 5d; g:sum score of items 6b, 6c, reversed 6d; h:sum score of items 7a, 7c & 7d
In Table
Second field testing of the ALPHA short (N = 166): Answer frequencies and test-retest reliability scores.
Answer frequencies
Test-retest reliability scores
Item/Scale
Yes
No
NA
Agreement, %
ICC
Total
0.73a
a) Most of the houses in my neighbourhood are detached houses
33.7
66.3
89
b) There are many shops within easy walking distance of my home
74.7
25.3
92
c) There is a bus/tram station within easy walking distance of my home
92.2
7.8
92
d) There is a park within easy walking distance of my home
84.9
15.1
92
e) Walking is dangerous because of the traffic in my neighbourhood
7.8
92.2
90
f) Walking is dangerous because of the level of crime in my neighbourhood
4.2
95.8
95
a) There are trees along the streets in my neighbourhood
67.6
32.3
85
g) At my home, I have small sports equipment such as a ball, racquets, ... for my personal use
82.5
17.5
92
h) At
10.8
77.1
12.0
93
i) At
41.0
47.0
12.0
90
NA = Not applicable
ICC = Intraclass correlation coefficient
asum score of all items
Discussion
The purpose of this study was to assess test-retest reliability, predictive validity and feasibility of the ALPHA environmental questionnaire in samples of men and women from several European countries.
Reliability
All but two of the subscales (distance to local facilities scale and the safety scale) in the ALPHA questionnaire showed low levels of internal consistency. This is appropriate for environmental variables as the aim of an environmental questionnaire is to sample possible indicators of one environmental construct which are often not intercorrelated, so Cronbach alphas are often low. In the literature similar internal consistency values for environmental scales are found e.g. the Cronbach alphas of the Cycling for Transport questionnaire range from 0.46 to 0.70
In the first testing, moderate to good test-retest reliability was evident for the ALPHA questionnaire (ICCs of the subscales ranged from 0.66-0.86); while in the second field testing all subscales showed good reliability (ICCs ranged from 0.71-0.87). The ICCs were not significantly different between two test-phases (t = -1.207, p = 0.247), but there was a significant increase (t = -2.779, p = 0.008) in percentages of agreement from the first (range 52-99%) to the second field testing (range 59-99%). Similar test-retest values have been reported for other environmental questionnaires, e.g. ICCs for the test-retest reliability of the NEWS subscales ranged from 0.58 to 0.80 in one study
Overall, our findings suggest that the final version of the ALPHA questionnaire has good reliability, comparable to that found in equivalent instruments.
The reliability results of the ALPHA short were more difficult to compare between both field tests, given the changes to answer categories (i.e. ICCs for the individual items could not be analysed). However, for the total score, reliability was good and of similar magnitude in both testing phases (0.75 and 0.73 respectively). For the individual items the proportion of agreement found in the first field testing (50% to 83%) increased significantly (t = -9.175, p < 0.001) in the second field testing (85% to 95%); showing greater item stability in the later version. Reliability values of the ALPHA short compared favourably with other instruments, e.g. proportion of agreement for environmental items of South Carolina (47% to 94%), for the NEWS (33% to 98%) and for the St Louis Instrument (40% to 96%)
Predictive validity
In general, moderate predictive validity was found for both versions of the ALPHA environmental questionnaire. As expected, most associations were found between the environmental scales and "walking for transport" measured with the IPAQ. This is consistent with the transport literature in which urban planners show that certain environmental factors, like those included in the ALPHA questionnaire, are associated with increased levels of walking
With the accelerometers, context-related physical activity could not be assessed, but almost all associations between the perceived environment and low physical activity were in line with the results of the IPAQ. Contrasting results between IPAQ and accelerometers were found for "safety from traffic" and "aesthetics". Somewhat unexpectedly, these environmental factors were related with lower levels of walking for transport measured with the IPAQ in women. However, we did find associations in the hypothesised direction with the Actigraph data, namely "safety from traffic" and "aesthetics" were related with respectively more minutes of vigorous physical activity and more minutes of physical activity at low intensity. In the literature, aesthetics and physical activity behaviour are consistently positively related, but the association between safety and physical activity behaviour is less consistent
Feasibility
Both versions of the questionnaire appeared feasible in terms of completion time. The 49-item version was completed in a relatively short period of time compared to other environmental questionnaires requiring only an average of 6 minutes to complete. Given the low participant burden we recommend using this version as it gives a better overall picture of the built environment than ALPHA short.
Strengths and Limitations
The ALPHA questionnaire has undergone extensive conceptual and field testing and refinement. It is now ready for further assessment within different populations and environments across Europe.
One of the limitations in this study was the high education level of our participants in the second series of field testing compared with our first field test participants, which might explain some of the improvements seen in the test-retest scores.
A second limitation of this study are the different sampling methods (probability and non-probability) used in the three countries and the possible clustering within each country, which may have resulted in more positive results.
Another possible limitation is that objective environmental measurements were not included in the testing and thus the perceptions could not be compared with objective data. However, it has to take into account that objective and subjective measures of the build environment are two different concepts. Previous studies
Our questionnaire was based on extensive synthesis and adaptation of previous similar instruments
Conclusion
The ALPHA questionnaire is a good instrument for measuring environmental perceptions related to physical activity behaviour, with moderate to good reliability, predictive validity and feasibility. The instrument was developed in collaboration with an international expert group and was subject to different test phases. However, we acknowledge the considerable challenges of this field, and in light of the limitations outlined believe that further testing is required to improve generalisability to other European countries. Future testing will look to correlate the perceived environmental outcomes with other physical activity-related measures such as fitness, heart rate and geographic information system (GIS) measured objective environmental measures. By the means of this paper we would also like to make the ALPHA questionnaire available to other researchers who could further investigate whether our questionnaire represents an appropriate instrument for assessing perceptions of the environment related to physical activity across Europe. The questionnaire (in different languages) and a manual can be found on the IPEN website
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
MS, PO, IDB, HR, CF, JMO and HS identified the research question and design of this study as part of the ALPHA project. MV, JG, CG and ST collected the data. HS coordinated translation process and data collection, did the statistical analysis and drafted the manuscript. All authors contributed to synthesising the results and critical revision of the manuscript, and approved the final version.
Acknowledgements
This study is being carried out with financial support from the Commission of the European Communities, specifically the Public Health Programme 2003-2008 of the Directorate General Health and Consumer Protection Luxembourg, 800259 'Instruments for Assessing Levels of Physical Activity and related Health Determinants' (ALPHA). The study does not necessarily reflect the Commission's views and in no way anticipates the Commission's future policy in this area. The authors would like to thank Dirk Meusel, Benedicte Deforche, Greet Cardon and Femke De Meester for their help in the translation process and cognitive testing. We are extremely grateful to the international experts who were willing to participate in our expert meeting to discuss the results of our first field testing, and wish to give special thanks to all the participants for their willingness to participate.