Lift Yourself Up: The Short-Term Associations Between Strength Training and Mood States and the Longer Term Development of Physical Capital and "Grit" Among People Recovering From Substance Use Disorders.

Mind Body Connect is a charity that delivers community-based physical exercise (PE) classes to people in recovery from substance use disorders. This study aimed to identify the contribution that strength training played in the development of positive short- and long-term psychological attributes for people recovering from substance use disorders by assessing (a) the short-term associations between participation in group exercise classes (N = 43, t = 2,940) and (b) the prospective long-term association between strength development and individuals' self-assessed level of "grit" among participants for whom strength training became a habitual activity (N = 13, median 8 weeks supported training). Participants completed demographic, Profile of Mood States-Adapted Short Form, and Short Grit Scale questionnaires before and after each strength training session over a period of 45 noncompulsory training sessions between February 2020 and March 2021. Weekly training logs recording the weight lifted were normalized into a measure of physical capital development. Short-term associations were tested using multilevel regression models predicting change in mean Grit score with interactions for gender; long-term associations were assessed through the use of latent growth models. We found that training sessions were associated with weak to moderate reductions ($\beta$ = -0.112 to -0.533) in many negative mood states but elevated fatigue (${\beta }_{\mathrm{MEN}}$ = 1.071, ${\beta }_{\mathrm{WOMEN}}$ = 0.397). Latent growth in recorded strength was strongly associated with latent growth in self-assessed grit ($\beta$ = 0.674). The findings suggest that PE classes and supported long-term strength training may assist with the development of recovery capital.