The aim of this study was to assess the compliance rate and long term effect on lumbar bone loss during a 3-year daily psoas muscle training program in postmenopausal women. Computerized tomography was carried out at the beginning, 1 year and 3 years later (respectively TDM1, TDM2 and TDM3) in order to measure lumbar trabecular bone mineral density. From TDM1 to TDM2, a randomized study was conducted to evaluate the effect of a 1-year training of psoas muscle (psoas group, GP1-2) vs 1-year training of deltoid muscle (control group, GC1-2). Seventy-eight women were included, 67 performed the training and 49 were assiduously trained. The bone loss was lower in the assiduous GP1-2 women than in the assiduous GC1-2 women (respectively 0.14 ± 11.21 mg/cm 3 and - 8.87 ± 12.75 mg/cm 3 , P = 0.01). The 67 women who completed the first trial were asked to practice psoas exercises for 2 additional years. Twenty-one women performed this psoas training during 3 years from CT1 to CT3 (GP1-3) whereas 14 were controls during the same period (GC2-3). The lumbar bone loss was lower in the GP1-3 than in the GC1-3 (respectively - 9.26 ± 28.45 mg/cm 3 and - 16.79 ± 8.51 mg/cm 3 , P = 0.02). The compliance rate (in respect to the 78 included women) was respectively 85% and 42% 1 and 3 years later. The attendance rate was respectively 73% and 88%. Thirty-five percent of women stopped training, feeling it was uninteresting.Cette etude prospective evalue l'effet sur la perte osseuse lombaire de l'entrainement des psoas en decharge (60 flexions de chaque hanche quotidienne avec un poids de 5 kg sur la cuisse) et la compliance au terme d'un suivi de 3 ans. La densite osseuse vertebrale trabeculaire lombaire a ete mesuree par tomodensitometrie (TDM) a l'inclusion, puis 1 an et 3 ans plus tard (respectivement TDM1, TDM2, TDM3). Entre TDM1 et TDM2, les effets de deux entrainements, sollicitant soit les psoas (groupe psoas, GP1-2), soit les deltoides (groupe temoin, GC1-2), ont ete compares. Soixante-dix-huit femmes ont ete incluses; 67 femmes ont fait l'entrainement et 49 femmes ont ete assidues. Chez les femmes assidues, la perte osseuse lombaire de GP1-2 a ete inferieure a celle de GC1-2 (respectivement +0,14 ± 11,21 mg/cm 3 et -8,87 ± 12,75 mg/cm 3 , p = 0,01). Apres TDM2, l'entrainement des psoas a ete propose a toutes les femmes. Entre TDM1 et TDM3, 21 femmes ont pratique l'entrainement des psoas sans interruption (GP1-3) et 14 femmes ne l'ont jamais fait (GC1-3). La perte osseuse de GP1-3 a ete inferieure a celle de GC1-3 (respectivement -9,26 ± 28,45 mg/cm 3 et -16,79 ± 8,51 mg/cm 3 , p = 0,02). Le taux de compliance (calcule a partir des 78 femmes incluses) est egal a 85 % au bout de 1 an, et a 42 % au terme de 3 ans, avec un taux d'assiduite egal a 73 et 88 %. Trente-cinq pour cent des femmes ont arrete la gymnastique par lassitude.