Gaps in the Evidence

Across all three subsections, the majority of research is being conducted in high income countries. To truly understand the LTPA relationship with psychosocial outcomes, we need better diversity in study samples and countries of origin. It is difficult (and nearly impossible) to generalize these results on a worldwide scale without evidence representing our global society. Notably, research in other countries should be primarily led by researchers from those countries. If research is to be done in partnership, researchers must avoid being “helicopter” researchers and engaging in tokenistic research. They must be sensitive to the long tradition of such practices and ensure meaningful engagement (Adame, 2021; Anderson, 2021). Meaningful engaging in research can be conducted by following principles, such as the integrated knowledge translation principles for SCI research (Gainforth et al., 2021).

Although there is a growing body of literature examining the relationship between LTPA and anxiety and depression, there remains some important gaps. Most studies examined symptoms of anxiety and/or depression rather than identifying the impact of LTPA on people with SCI who have a clinical anxiety/depression diagnosis. It is therefore difficult to ascertain the potential clinical implications of participating in LTPA without conducting research on people who have a clinical diagnosis. Similarly, the ideal dosage of LTPA on these psychological outcomes remains largely unknown. Conducting high quality interventions to determine the impact of LTPA on anxiety and depression and identifying the ideal dose of LTPA is needed to fill an important gap in the SCI research. These interventions should ensure that anxiety and depression are their primary outcome and include follow-up assessments to ascertain the potential longer-term impact of LTPA. Furthermore, most of these studies examined depression and anxiety among men. More research is needed to examine sex/gender differences and possible considerations sex/gender has on the LTPA and depression/anxiety relationship.

A large body of research has shown support for the LTPA and QOL relationship. Notably, research on LTPA and subjective QOL has grown in the past two decades. This continued growth is encouraging because the LTPA and subjective QOL relationship needs further unpacking in light of some studies reporting non-significant results. Future research could differentiate the relationship between LTPA and the physical, psychological, and social domains of QOL. Such information may help optimize the selection of the types of LTPA and measures of QOL when developing and evaluating LTPA interventions and programs.

A limited body of research has explored the relationship between LTPA and participation-related outcomes, requiring more research to strengthen conclusions. Future research could aim to explore the relationship between LTPA and the various types and domains of participation. Given participation is a broad concept and most studies in this review focused on participation as one broad outcome, we have little knowledge of specific relationships between different types of LTPA and different participation-related outcomes. Gaining evidence for these specific associations could inform interventions and community-based programs. Furthermore, participation may need to be a primary outcome in LTPA interventions. Bringing the focus on participation as a key outcome may assist in selecting types of physical activities used in an intervention and enhance our understanding of this relationship. Finally, studies could aim to examine whether LTPA has a stronger or weaker relationship with person-perceived or society-perceived participation. Such an understanding is required to ensure researchers select the participation-related outcomes that are most sensitive to change from participating in LTPA.

Finally, across all sections in this review, the majority of interventions and trials have been conducted with small samples and mostly with men. These small samples reduce the likelihood of identifying significant results even if moderate effect sizes were found. Interventions and trials with larger sample sizes are needed. Larger samples in LTPA interventions would also help to fill some important gaps in the literature, including examining sex/gender differences in these relationships. For example, what is the ideal dose of LTPA to increase QOL or reduce depression? What type of physical activity (e.g., yoga, tai chi, resistance training) is ideal to enhance QOL or reduce anxiety? What are mechanisms that may explain the relationship between LTPA and these psychological and participation-related outcomes and are they different for men and women? As such, there remains a number of different avenues to explore before coming to a comprehensive understanding of the effect and relationship of LTPA with depression, anxiety, quality of life, and participation-related outcomes.