Effects of immersive virtual reality-based physical activity interventions on anthropometric variables and physical fitness in university students: protocol for a systematic review and meta-analysis

Abstract

Introduction

Physical inactivity and sedentary behaviour are common among university students and may negatively affect body composition and physical fitness. Immersive virtual reality (IVR) has emerged as a promising strategy to promote physical activity through engaging and interactive exercise experiences. Although previous reviews have explored virtual reality-based interventions across diverse populations and outcomes, the evidence regarding the effects of IVR-based physical activity interventions on anthropometric variables and physical fitness in university students has not been systematically synthesised.

Methods and analysis

This protocol is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 statement and has been prospectively registered in PROSPERO (CRD420261377808). Electronic searches will be conducted in PubMed/MEDLINE, Scopus, Web of Science Core Collection, SPORTDiscus, APA PsycINFO and CINAHL, with additional searches of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. Eligible studies will include university students exposed to immersive virtual reality-based physical activity, exercise or active exergaming interventions. Comparators may include no-intervention controls, waitlist controls, usual activities, conventional exercise programmes or non-immersive virtual reality interventions. Outcomes will include objectively measured anthropometric variables and physical fitness indicators. Study selection, data extraction, risk-of-bias assessment and certainty-of-evidence evaluation will be conducted independently by two reviewers using revised Cochrane risk-of-bias tool for randomised trials, risk of bias in non-randomised studies of interventions and Grading of Recommendations Assessment, Development and Evaluation methodologies. Where appropriate, random-effects meta-analyses will be performed.

Ethics and dissemination

Ethical approval is not required because this review will synthesise data from previously published studies and will not involve the collection of primary data. Findings will be disseminated through publication in a peer-reviewed journal and presentation at scientific conferences.

PROSPERO registration number

CRD420261377808.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• This protocol is prospectively registered in PROSPERO and is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 statement.

• Study selection and data extraction will be performed independently by two reviewers, with disagreements resolved by consensus or consultation with a third reviewer.

• Risk of bias will be assessed using design-specific tools, including revised Cochrane risk-of-bias tool for randomised trials for randomised controlled trials and risk of bias in non-randomised studies of interventions for non-randomised studies.

• The certainty of evidence for each outcome will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach.

• The feasibility of quantitative synthesis may be limited by the number of eligible studies and heterogeneity across study populations, interventions, virtual reality devices and outcome measures.

Introduction

Physical inactivity and sedentary behaviour among university students constitute a relevant public health concern, and the university stage represents a particularly sensitive period for the consolidation of habits related to movement, exercise and body weight control.¹ Among university students, academic demands, changes in daily routines and reduced time allocated to physical activity may promote sedentary behaviours and a progressive deterioration in indicators related to physical health.²

In this context, immersive virtual reality has emerged as an innovative strategy for promoting physical activity and exercise, as it enables the development of interactive experiences through immersive devices that enhance the sense of presence in simulated three-dimensional environments.³ Immersive virtual reality-based exercise may enhance enjoyment and motivation toward physical activity; however, these potential benefits are not unique to immersive technologies, as exergaming approaches more broadly have also been associated with increased exercise enjoyment and may support adherence to physical activity.⁴

Emerging evidence suggests that immersive virtual reality-based physical activity interventions may improve both physiological and psychological variables in university students, including indicators of physical response to exercise, motivation and mood state.⁵ In university students, a 12-week randomised controlled trial reported significant improvements in cardiorespiratory fitness following an immersive virtual reality-based physical activity intervention compared with a control group that maintained their usual activities.⁶ Likewise, a randomised trial conducted in university students with simple obesity found significant reductions in body weight, body mass index, waist circumference and hip circumference after a virtual reality cycling intervention combined with music compared with traditional cycling without virtual reality or music.⁷

Despite these findings, the synthesised evidence remains limited for specifically answering the question of the effects of immersive virtual reality on anthropometric variables and physical fitness in university students.¹ Previous reviews have examined immersive virtual reality-based physical activity across broader age and population groups and have considered diverse outcomes, including physical activity, exercise performance, psychological and cognitive responses, motivation and user experience, alongside physical health and fitness outcomes.^{8 9} Consequently, these reviews do not provide a population-specific synthesis of the effects of immersive virtual reality-based physical activity interventions on objectively measured anthropometric and physical fitness outcomes in university students. For this reason, conducting a systematic review focused on university students is fully justified, as it will provide a more precise and methodologically delimited synthesis of the available evidence. Additionally, if sufficient homogeneity across studies and adequate data availability are identified, a meta-analysis will be conducted to quantitatively integrate the observed effects.

Objective

The objective of this study protocol is to describe a clear and rigorous methodology for conducting a systematic review and, where feasible, a meta-analysis of the effects of immersive virtual reality-based physical activity interventions on anthropometric variables and physical fitness in university students.

Methods

This protocol is reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 statement¹⁰ (online supplemental file 1). The systematic review and meta-analysis will be conducted according to the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions¹¹ and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement.¹² This protocol has been prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO; registration number CRD420261377808). At the time of manuscript revision, the systematic review remains ongoing, and the definitive literature searches, study selection, data extraction and data synthesis have not yet been conducted.

Eligibility criteria

The eligibility criteria for this protocol will be established according to the Population, Intervention, Comparison, Outcomes, and Study design¹¹ framework. Studies identified through the database searches will be considered eligible if they meet the following criteria.

Participants

Studies including university students formally enrolled in a higher education institution at either undergraduate or postgraduate level will be considered, regardless of age, sex or academic discipline. No age restriction will be applied, as eligibility will be determined by student status rather than chronological age. Studies including mixed populations (eg, university students and university staff or other non-student participants) will be eligible only when data for university students are reported separately or can be extracted separately. Studies in which data for university students cannot be distinguished from those of other populations will be excluded.

Intervention

Eligible studies must evaluate physical activity, exercise or active exergaming interventions delivered through immersive virtual reality. Immersive virtual reality will be defined as interventions using head-mounted displays, virtual reality headsets or other immersive visualisation devices designed to generate a sense of presence within a three-dimensional virtual environment.¹³ For the purposes of this review, a structured physical activity or exercise component will be defined as an intervention in which active bodily movement is an integral part of the immersive virtual reality experience and is intentionally designed to elicit physical activity or exercise through a predefined session or intervention protocol. The protocol must provide sufficient information to identify the physical activity or exercise component, such as the type of activity, session duration, frequency, intensity or progression. Interventions involving passive virtual reality exposure or only incidental/minimal movement without an intended physical activity or exercise component will not be considered eligible. Studies assessing exclusively non-immersive virtual reality interventions will also be excluded.

Comparison

Comparator groups may include no-intervention controls, waitlist controls, usual activities, conventional physical activity or exercise programmes, or non-immersive virtual reality-based interventions.

Outcomes

Studies will be eligible if they report pre- and post-intervention data or between-group comparisons for at least one anthropometric or physical fitness outcome. Anthropometric outcomes may include body weight, body mass index, waist circumference, hip circumference, body fat percentage or other objectively measured indicators of body composition. Physical fitness outcomes may include cardiorespiratory fitness, muscular strength, muscular endurance, flexibility, balance, agility, speed or other objectively measured components of physical fitness. Only outcomes assessed using objective measurements, standardised physical fitness tests or instrument-based assessments will be considered eligible. This criterion was established to ensure that the review focuses on directly measured changes in anthropometric characteristics and physical fitness and to enhance comparability across studies while reducing the influence of recall, reporting and subjective measurement biases. Studies relying exclusively on self-reported or subjectively estimated anthropometric or physical fitness outcomes will therefore be excluded. Studies reporting both eligible objectively measured outcomes and self-reported outcomes may be included, but only the objectively measured anthropometric and physical fitness outcomes will be considered for the present review.

Study design

Eligible studies will include randomised controlled trials, non-randomised controlled intervention studies, and quasi-experimental intervention studies evaluating immersive virtual reality-based physical activity, exercise or active exergaming interventions. Systematic reviews, narrative reviews, meta-analyses, study protocols, editorials, letters to the editor, conference abstracts, case reports and case series will be excluded. Only full-text articles published in peer-reviewed scientific journals will be considered eligible; theses, dissertations and other unpublished material will be excluded. No restrictions will be applied regarding year of publication or language. For potentially eligible articles published in languages not spoken by the review team, translation will be undertaken using appropriate translation software. Where necessary, translated information will be verified with the assistance of a proficient speaker or professional translation service to ensure accurate assessment of eligibility and data extraction.

Information sources

The search for studies will be conducted in PubMed/MEDLINE, Scopus and Web of Science Core Collection. In addition, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (WHO ICTRP) will be searched to identify ongoing or completed but potentially unpublished studies and associated publications. The reference lists of included studies and relevant reviews will also be screened to identify potentially eligible studies not retrieved through the electronic searches.

Search strategy

The search for studies will be conducted in the PubMed/MEDLINE, Scopus, Web of Science, SPORTDiscus, APA PsycINFO and CINAHL databases, from their inception to the date of the final search, with no restrictions on publication year or language. SPORTDiscus, APA PsycINFO and CINAHL will be searched via the EBSCOhost platform. In addition, ClinicalTrials.gov and the WHO ICTRP will be searched to identify ongoing or completed but potentially unpublished studies and any associated publications. Trial registry records without eligible published outcome data will not be included in the quantitative synthesis but will be considered when assessing the completeness of the available evidence and potential publication bias.

The search strategy will be developed using conceptual blocks related to the population and intervention, including terms capturing immersive virtual reality and physical activity or exercise, combining controlled vocabulary and free-text terms adapted to each database. In PubMed, MeSH terms will be used together with keywords searched in the title and abstract fields, whereas in Scopus and Web of Science, free-text terms and Boolean operators will be applied according to the syntax requirements of each platform. SPORTDiscus, APA PsycINFO and CINAHL will each be searched separately via the EBSCOhost platform, using free-text terms and Boolean operators adapted to the search functionality of each database. Search strategies for ClinicalTrials.gov and WHO ICTRP will be adapted to the search functionality of each registry. Outcome-related terms will not be used as a mandatory search concept in order to maximise search sensitivity and reduce the risk of missing potentially eligible studies in which relevant anthropometric or physical fitness outcomes are not reported in the title, abstract or indexing terms. Outcome eligibility will instead be assessed during the study selection process. No study design filters will be applied to the electronic database searches in order to maximise search sensitivity and minimise the risk of excluding potentially eligible randomised, non-randomised or quasi-experimental intervention studies because of incomplete or inconsistent reporting or indexing of study design. Study design eligibility will instead be assessed during the study selection process. The complete search strategies for all bibliographic databases and trial registries are provided in online supplemental file 2.

Selection of studies

All identified records will be exported to the bibliographic reference manager Mendeley Reference Manager (V.2.139; Elsevier, London, UK). After duplicate records have been removed, two reviewers will independently screen titles and abstracts and subsequently assess the full texts of potentially eligible studies. Any disagreements will be resolved through discussion and, if necessary, by consultation with a third reviewer. The study selection process will be documented using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.¹²

Data extraction

Data extraction will be performed independently by two reviewers using a standardised data extraction form. Information will be collected on author, year, country, study design, sample size, population characteristics, intervention details, comparators, duration, frequency, intensity, type of virtual reality device, as well as the reported anthropometric and physical fitness outcomes. When published information is incomplete or unclear, attempts will be made to contact the corresponding authors for clarification.

Risk of bias assessment

The methodological quality of the included studies will be assessed independently by two reviewers. Randomised controlled trials will be evaluated using the Revised Cochrane risk-of-bias tool for randomised trials (RoB 2),¹⁴ which covers five domains: bias arising from the randomisation process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in outcome measurement, and bias in the selection of the reported result. Each domain will be judged as low risk of bias, some concerns or high risk of bias. The overall risk-of-bias judgement for each study will be considered low when all domains are rated as low risk, some concerns when at least one domain raises some concerns and high when at least one domain is rated as high risk of bias.

Non-randomised and quasi-experimental studies will be assessed using the risk of bias in non-randomised studies of interventions (ROBINS-I) tool,¹⁵ which includes seven domains: bias due to confounding, bias in the selection of participants, bias in the classification of interventions, bias due to deviations from intended interventions, bias due to missing data, bias in the measurement of outcomes and bias in the selection of the reported results. Each domain will be rated as low, moderate, serious or critical risk of bias. The overall risk-of-bias judgement will be considered low when all domains are rated as low risk, moderate when all domains are judged as low or moderate risk, serious when at least one domain is classified as serious risk in the absence of any critical-risk domains, and critical when at least one domain is judged to be at critical risk of bias.

Certainty of evidence

The certainty of the evidence for each outcome included in the review will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.¹⁶ The certainty of evidence will be rated as high, moderate, low or very low based on the evaluation of five domains: risk of bias, inconsistency, indirectness, imprecision and publication bias.

For outcomes derived primarily from randomised controlled trials, the certainty of evidence will initially be considered high and may be downgraded according to limitations identified within the GRADE domains. For outcomes derived from non-randomised studies, the certainty of evidence will initially be considered low and may be downgraded or upgraded when appropriate according to GRADE recommendations.

Risk-of-bias judgements obtained using the RoB 2 and ROBINS-I tools will contribute to the assessment of the risk-of-bias domain within GRADE. Two reviewers will independently perform the certainty assessment, and any disagreements will be resolved through discussion or consultation with a third reviewer. Summary of findings tables will be generated to present the certainty ratings and the main findings for each outcome.

Data synthesis

A meta-analysis will be considered for intervention studies reporting sufficient pre- and post-intervention or between-group data, when participants, intervention and methodological characteristics are considered sufficiently comparable to justify quantitative pooling. Studies providing insufficient data for quantitative synthesis will be included in the systematic review only. When required, corresponding authors will be contacted at least twice to obtain missing or additional data; if no response is received, these studies will remain included in the systematic review.

For studies including multiple eligible intervention or comparator groups, data will be handled according to Cochrane Handbook recommendations to avoid double counting of participants in the meta-analysis. When appropriate, intervention groups may be combined, or comparator groups may be split to ensure the independence of effect estimates.

For continuous outcomes, mean differences with 95% CIs will be calculated when measurement scales are comparable. When different scales are used to assess the same construct, the standardised mean difference with 95% CIs will be calculated. If dichotomous outcomes are identified, these will be analysed using relative risks or ORs, as appropriate.

When meta-analysis is considered appropriate, pooled effect estimates will be calculated using a random-effects model, given the expected heterogeneity in participants, intervention and methodological across studies.

If quantitative synthesis is not considered appropriate because of insufficient data or substantial heterogeneity in participants, intervention or methodological characteristics, a structured narrative synthesis will be undertaken. Studies will be grouped primarily according to outcome domain (anthropometric outcomes and physical fitness outcomes) and, within each domain, by specific outcome (eg, body weight, body mass index, waist circumference, cardiorespiratory fitness, muscular strength). Where appropriate, findings will also be considered according to comparator type and relevant characteristics of the immersive virtual reality intervention. The narrative synthesis will describe and compare the direction, magnitude and consistency of effects across studies, together with study characteristics, methodological differences and risk-of-bias assessments. Where effect estimates and CIs are available but statistical pooling is not appropriate, these will be presented and interpreted without combining them quantitatively.

Statistical heterogeneity will be assessed using Cochran’s χ² test and the I² statistic, which quantifies the percentage of total variability attributable to between-study heterogeneity. According to recommendations from the Cochrane Handbook for Systematic Reviews of Interventions, I² values of 0–40% may indicate low heterogeneity, 30–60% moderate heterogeneity, 50–90% substantial heterogeneity and 75–100% considerable heterogeneity. However, the interpretation of heterogeneity will not rely exclusively on I² values and will also consider the magnitude and direction of effects, CI overlap, and the participants, intervention and methodological characteristics of the included studies.¹¹

If sufficient data are available, subgroup analyses will be conducted based on sample characteristics, type of intervention, programme duration and participants’ baseline status (underweight, normal weight, overweight or obesity). Subgroup analyses will only be performed when at least two studies are available within each subgroup category considered relevant for comparison.

Sensitivity analyses will be conducted by excluding studies judged to be at high risk of bias and by performing leave-one-out analyses to evaluate the robustness of the pooled estimates.

Publication bias will be assessed through visual inspection of funnel plots and Egger’s regression test when at least 10 studies are included in a meta-analysis, in accordance with recommendations from the Cochrane Handbook for Systematic Reviews of Interventions and previous methodological literature, as tests for funnel plot asymmetry have limited power when fewer studies are available.^{11 17}

For studies in which meta-analysis is considered appropriate, statistical analyses will be performed using R statistical software (R Foundation for Statistical Computing, Vienna, Austria), employing appropriate packages for meta-analysis and data visualisation.

Ethics and dissemination

Ethical approval is not required for this study because it is based exclusively on the analysis of data from previously published studies and does not involve the recruitment of participants, the collection of primary data or access to identifiable personal information. Consequently, informed consent is not applicable.

The findings of this systematic review and meta-analysis will be disseminated through publication in a peer-reviewed scientific journal and presentation at national and international conferences related to physical activity, exercise science, public health and digital health technologies. The review aims to provide researchers, health professionals, university educators and decision-makers with a comprehensive synthesis of the available evidence regarding the effects of immersive virtual reality-based physical activity interventions on anthropometric variables and physical fitness in university students. The results may also contribute to identifying research gaps and informing the development of future interventions and research in this field.

Discussion

The objective of this protocol is to explicitly and transparently describe the methods that will be used to synthesise the available evidence on the effects of immersive virtual reality-based physical activity interventions on anthropometric variables and physical fitness in university students. Additionally, this protocol seeks to establish rigorous methodological criteria for identifying, selecting, appraising, and, where feasible, quantitatively integrating the findings of primary studies, thereby providing a solid foundation for a future evidence synthesis in this field.

The present systematic review and meta-analysis is intended to address a clearly defined research question within a field that is still evolving. Although immersive virtual reality has shown steady growth as a strategy to promote participation in physical activity and exercise, the available evidence remains fragmented, and a large proportion of studies has focused on perceptual, motivational or user-experience outcomes rather than on specific physical outcomes in university populations.^{1 5 18} In this context, there remains a need for a synthesis focused exclusively on university students and on objective physical variables, such as anthropometric indicators and physical fitness outcomes.^{1 19} The relevance of this review is further supported by the fact that the university stage represents a critical period for the consolidation of health- and movement-related habits,²⁰ while digital and immersive strategies may offer attractive alternatives for enhancing adherence to exercise among university students.²¹ In addition, the evidence suggests that immersive virtual reality-based interventions may produce favourable effects on physical fitness indicators, perceived exertion, mood state and other responses associated with exercise practice.^{22 23}

The focus on objectively measured anthropometric and physical fitness outcomes is particularly relevant because these measures provide complementary information on physical health that cannot be fully captured by perceptual, motivational or user-experience outcomes. Anthropometric indicators, including body weight, body mass index, waist circumference and body composition, provide measurable information on adiposity and body composition, and these outcomes are responsive to exercise interventions in university populations.²⁴ Physical fitness components such as cardiorespiratory fitness and muscular strength provide complementary information on functional and physiological capacity, with cardiorespiratory fitness recognised as an important indicator of health in adults.²⁵ Assessing these outcomes objectively will therefore allow the review to determine whether immersive virtual reality-based physical activity interventions produce measurable changes in physical health rather than relying on perceived or self-reported indicators of these constructs.

Among the expected strengths of this protocol are the precise delimitation of the population, intervention and outcomes, as well as the application of internationally recognised methodological procedures for systematic reviews and quantitative synthesis. Taken together, the use of reporting guidelines, structured risk-of-bias assessment tools and formal strategies for evaluating the certainty of the evidence will contribute to improving the transparency, reproducibility and methodological rigour of the final review.

Nevertheless, certain limitations can also be anticipated. First, the number of eligible studies may be limited because of the specific population, intervention and outcome criteria established for this review. Second, methodological heterogeneity across studies is likely, particularly regarding the type of immersive device used, the exercise modality and dose, the duration of the interventions, sample characteristics and the outcomes assessed, which may limit the feasibility of conducting meta-analyses for all outcomes of interest. Despite these anticipated limitations, a systematic review was considered more appropriate than a scoping review because the primary purpose is not to map the extent and characteristics of the literature, but to address a focused question regarding the effects of immersive virtual reality-based physical activity interventions on predefined, objectively measured anthropometric and physical fitness outcomes in university students. The eligibility criteria and outcomes have been prespecified, and the review will include formal assessment of risk of bias and certainty of evidence to support the evaluation of intervention effects. Meta-analysis will be undertaken only when sufficient clinically and methodologically comparable data are available; otherwise, findings will be synthesised using the predefined structured narrative approach. Therefore, a potentially limited or heterogeneous evidence base does not alter the primary evaluative purpose of the review. Even so, a systematic synthesis focused on this population may provide a more precise basis for guiding future interventions, improving trial design and clarifying the potential of immersive virtual reality as a tool for promoting physical activity in the university setting.

The funder had no role in the design of this protocol; the planned collection, analysis or interpretation of data; the writing of the manuscript; or the decision to submit the manuscript for publication.