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Lydia Kwak, Maria Hagströmer and Michael Sjostrom


To be able to draw any conclusions regarding the health effects of occupational physical activity (OPA), more information is needed regarding valid measures to assess OPA. Aims were to compare OPA as assessed with the International Physical Activity Questionnaire long version (IPAQ-L) with OPA assessed with an accelerometer and to assess the contribution of OPA to total PA.


Working adults (n = 441; mean age = 49.4 yrs; 44% males) wore an accelerometer for 7 days in free-living situations and completed the IPAQ-L. Comparisons were made between IPAQ-L-work and accelerometer data limited to working time (Moderate and Vigorous PA (accelerometer-MVPA-work) and average intensity). Subgroup analyses were performed.


Spearman correlation was r = .46 (P < .01) between IPAQ-L-work and accelerometer-MVPA-work. Correlations ranged from r = .27 to r = .55 in respectively obese and overweight subjects. The contribution of IPAQ-L-work to IPAQ-total was 24.7%.


The IPAQ-L work domain is a moderately good measure of time spent on MVPA at work and can be used to assess the contribution of OPA to total PA. This study provides valuable information regarding the use of the IPAQ-L in assessing work domain specific PA, and underscores the importance of assessing OPA, as it can contribute for a substantial part to total PA.

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Maria Hagströmer, Barbara E. Ainsworth, Lydia Kwak and Heather R. Bowles


The quality of methodological papers assessing physical activity instruments depends upon the rigor of a study’s design.


We present a checklist to assess key criteria for instrument validation studies.


A Medline/PubMed search was performed to identify guidelines for evaluating the methodological quality of instrument validation studies. Based upon the literature, a pilot version of a checklist was developed consisting of 21 items with 3 subscales: 1) quality of the reported data (9 items: assess whether the reported information is sufficient to make an unbiased assessment of the findings); 2) external validity of the results (3 items: assess the extent to which the findings are generalizable); 3) internal validity of the study (9 items: assess the rigor of the study design). The checklist was tested for interrater reliability and feasibility with 6 raters.


Raters viewed the checklist as helpful for reviewing studies. They suggested minor wording changes for 8 items to clarify intent. One item was divided into 2 items for a total of 22 items.


Checklists may be useful to assess the quality of studies designed to validate physical activity instruments. Future research should test checklist internal consistency, test-retest reliability, and criterion validity.

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Tina Louisa Cook, Ilse De Bourdeaudhuij, Lea Maes, Leen Haerens, Evangelia Grammatikaki, Kurt Widhalm, Lydia Kwak, Maria Plada, Luis Alberto Moreno, Yannis Tountas, Antonis Zampelas, Yannis Manios and on hehalf of the HELENA group


The aim was to examine if psychosocial determinants (attitudes, self-efficacy, social support from a sports partner) and perceived environmental barriers (PEB) of physical activity (PA) mediated the effect of a 3-month Internet-based intervention on PA in European adolescents.


A sample of 536 adolescents (51% boys) aged 12–17 years were randomly assigned to intervention or control condition. Questionnaires were used to assess different PA behaviors, psychosocial determinants and PEB at baseline and at 3-month follow-up. Mediating effects were assessed with the bootstrapping method.


PEB regarding neighborhood safety mediated the effect of the intervention on all PA indices. PEB regarding sports facilities availability at neighborhood and PEB regarding sport-related facilities availability at school mediated the effect of the intervention on moderate to vigorous PA (MVPA) and moderate PA (in leisure time and at school, respectively). Social support from a sports partner suppressed the effect of the intervention on vigorous PA and MVPA. No other factor had a mediation effect.


All PEB measures appear to mediate PA behaviors of different intensities and in different contexts. Interventions promoting PA in adolescents should also focus on improving the targeted PEB as mediators of engagement in PA to bring the desired effects in actual behaviors.