Background:Previous evidence has shown physical function (PF) improvements after physical exercise programs in fibromyalgia1. However, research comparing the efficacy of land vs. water-based programs is scarce.Objectives:This study aimed at comparing the effects of two exercise interventions (land- and water-based) on PF in patients with fibromyalgia.Methods:A total of 262 women were initially randomized and 152 (age:50.6 ±7.7 years) completed all the assessments with an attendance ≥70% (control n=62, land-based n=48, water-based n=42). The intervention groups trained three non-consecutive days/week (60 min/session) during 24 weeks. Every session consisted of exercises focused on improving cardiorespiratory fitness, muscle strength, and flexibility. Physical function components were assessed with the Functional Senior Fitness Test battery, and a standardized global PF index was calculated. Pre-, post- and re-test (12-week detraining) assessments were conducted. Groups did not differ in sex, sociodemographic characteristics, disease duration, drugs intake, and body mass index. Analysis of covariance was used to test the differences in changes from baseline (post-test vs. pre-test and re-test vs. pre-test) between groups using age, pain sensitivity, and baseline outcomes values as covariates.Results:Land- and water-based exercise groups improved lower body strength (mean difference; 95% confidence interval=2.8; 1.8, 3.8 and 1.7; 0.6, 2.8, respectively), upper body strength (4.8; 2.8, 6.8 and 3.5; 1.4, 5.6, respectively), and agility (-0.8; -1.2, -0.4 and -0.4; -0.8, -0.0, respectively) compared to the control group (all, P≤0.033). Additionally, land-based exercise group improved lower body flexibility and cardiorespiratory fitness compared to both the control (6.4; 2.8, 9.9 and 55.0; 31.0, 79.2, respectively) and water-based (5.4; 1.7, 9.2 and 37.5; 11.4, 63.6, respectively) groups (all, P≤0.002). Global PF improved in the land-based compared to the control group (0.4; 0.2, 0.5, P<0.001) and the water-based group (0.2; 0.0, 0.4, P=0.019). After the detraining period, land- and water-based groups maintained improvements in upper body strength (3.1; 1.2, 5.0 and 2.2; 0.1, 4.2, respectively) compared to the control group (all, P≤0.032). Land-based exercise group maintained improvements in lower body flexibility (5.1; 1.5, 8.8), lower body strength (1.7; 0.8, 2.6), agility (-0.6; -1.0, -0.3) and cardiorespiratory fitness (31.0; 6.8, 55.2) compared to control group (all, P≤0.007), and agility (-0.5; -0.9, -0.1) and cardiorespiratory fitness (40.2; 11.7, 68.7) compared to the water-based group (all, P≤0.014). The improvements in global PF were maintained in the land-based group compared to the control group (0.1; 0.0, 0.3, P=0.049).Conclusion:Land- and water-based exercise interventions are overall effective to improve PF in patients with fibromyalgia. However, the land-based exercise intervention presented greater effectiveness compared to the water-based exercise intervention. Improvements were overall sustained in the land-based group after a 12-week detraining period.References:[1]Macfarlane, G.J.; Kronisch, C.; Dean, L.E.; Atzeni, F.; Häuser, W.; Fluß, E.; Choy, E.; Kosek, E.; Amris, K.; Branco, J.; et al. EULAR revised recommendations for the management of fibromyalgia. Ann. Rheum. Dis. 2017, 76, 318–328.Acknowledgments:This study was supported by the Spanish Ministry of Economy and Competitiveness (I+D+i DEP2010-15639; I+D+I DEP2013-40908-R) and the Spanish Ministry of Education, Culture and Sport (FPU15/00002).Disclosure of Interests: :None declared