BACKGROUND: The gluteal muscles have been very important throughout the evolution of mankind for the adoption of the bipedal posture. Over the past 15 years, the intramuscular technique has become popular and has been improved, with enhanced results and reduced levels of postoperative complications. The insertion of gluteal implants within the musculature may be an intrinsic compression factor of these muscles. The objective of the present study was to evaluate the gluteus maximus function and its variation over a 12-month period after the insertion of the implant. METHODS: This was a prospective, controlled, clinical study. All subjects were female patients, with anthropometric characteristics and body mass index within preset limits to establish similar groups. Isokinetic test gluteus computed tomographic scans and clinical nutritional assessment were conducted in four stages during the study period: preoperatively and 3, 6, and 12 months after surgery. RESULTS: The study group presented 6.14 percent muscle atrophy to the left and 6.43 percent muscle atrophy to the right after the procedure. Muscle strength presented differences in hip flexion and adduction tests. CONCLUSIONS: The gluteus maximus muscle presents atrophy secondarily to gluteal augmentation surgery with implants. Variations in gluteus maximus muscle strength should not be attributed primarily to the surgical procedure or to the implants; physiologic and multifactorial variations should also be considered. Strength and volume variations did not show a significant correlation. Gluteal augmentation with implants was effective in improving the waist-to-hip ratio and in changing the anthropometric pattern from android to gynoid. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.