Resistance Training to Prevent Muscle Loss During Treatment With Tirzepatide

Inclusion Criteria: Age 1. Are ≥ 18 years and ≤ 60 years of age Weight 2. Have a body mass index (BMI) of ≥ 30 kg/m2 3. Have a history of at least 1 self-reported unsuccessful dietary effort to lose body weight 4. In the investigator's opinion, are well motivated, capable, and willing to * learn how to self-inject the investigational medicinal product (IMP), as required for this protocol * inject the IMP, and * comply with trial procedures for the duration of the trial, including adherence to scheduled visits, the prescribed resistance training program (if assigned to the experimental group), lifestyle recommendations, and other requirements as specified in the protocol Sex and contraceptive/barrier requirements \[only for women\] 5. Women of childbearing potential (WOCBP) may be enrolled only if one of the following applies: * They are completely abstinent as their preferred and usual lifestyle or exclusively in a same-sex relationship as their preferred and usual lifestyle and agree to remain abstinent or stay in a same-sex relationship without sexual relationships with males until 30 days after the last injection (\> 5 half-lives of tirzepatide) * They have a negative serum pregnancy test result at screening followed by a negative urine result ≤ 24 hours prior to the first injection, and they agree to use, from screening until 30 days after the last injection, either: * one highly effective method of contraception (failure rate \<1% per year) or * two complementary forms of effective contraception Note: The summary of product characteristics (SmPC) indicates that concomitant use with tirzepatide may reduce systemic exposure to oral contraceptives, particularly during dose escalation, potentially decreasing their contraceptive effectiveness. Therefore, the use of a barrier method in combination with oral contraceptives is required. Informed Consent 6. Are sufficiently proficient in German to understand the trial procedures and informed consent information 7. Are capable of providing written informed consent Exclusion Criteria: Medical Conditions Diabetes Related 1. Have known Type 1 Diabetes, a history of Type 2 Diabetes (including those in remission), a history of ketoacidosis of any aetiology, or a history of hyperosmolar hyperglycaemic state or coma 2. Have at least one laboratory value suggestive of diabetes during screening including: * glycated hemoglobin A1c (HbA1c) ≥6.5% (≥48 mmol/mol) * fasting glucose ≥126 mg/dL (≥7.0 mmol/L) Note: If a blood sample is collected under non-fasting conditions and the random glucose value is ≥200 mg/dL (≥11.1 mmol/L), an additional fasting blood sample will be obtained to confirm or exclude diabetes. Obesity Related 3. Have a self-reported reduction in body weight \>5 kg within 3 months prior to screening 4. Have a prior or planned surgical treatment for obesity (excluding liposuction or abdominoplasty if performed \>1 year prior to screening) 5. Have or plan to have endoscopic and/or device-based therapy for obesity or have had device removal within the last 6 months prior to screening (e.g., mucosal ablation, gastric artery embolization, intragastric balloon, duodenal-jejunal endoluminal liner) 6. Have obesity induced by other known endocrinologic disorders (e.g., Cushing syndrome) or diagnosed monogenetic or syndromic forms of obesity (e.g., Melanocortin 4 Receptor deficiency or Prader Willi Syndrome) Note: If endocrinological disorder is suspected, a dexamethasone suppression test should be performed to assess for possible hypercortisolism Other Medical 7. Are currently breastfeeding 8. Have structural cardiovascular disease (e.g., ischemic cardiovascular disease, heart failure, previous cerebrovascular accident \[stroke\]) 9. Have atrial fibrillation 10. Have uncontrolled hypertension (systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥100 mmHg) 11. Have any visual, neurological, musculoskeletal, or other physical impairment that, in the opinion of the investigator, would prevent the participant from independently and appropriately self-administering the IMP and/or performing the resistance training program as required by the protocol (e.g., significant muscle or joint pain, significantly limited range of motion) 12. Have renal impairment measured as estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2, calculated by Chronic Kidney Disease Epidemiology (CKD-EPI) 2021 creatinine-based equation during screening 13. Have a known clinically significant gastric emptying abnormality (e.g., severe gastroparesis or gastric outlet obstruction) or chronically take drugs that directly affect gastrointestinal motility 14. Have a history of chronic or acute pancreatitis Note: If acute pancreatitis is suspected, laboratory assessment of pancreatic amylase and/or lipase 15. Have thyroid-stimulating hormone (TSH) outside the range of 0.4 to 6.0 mIU/L at the screening visit Note: Participants receiving treatment for hypothyroidism may be included, provided their thyroid hormone replacement dose has been stable for at least 3 months and their TSH at screening falls within the range indicated above. Note: Participants with a history of subclinical hypothyroidism but a TSH at screening within the range indicated above may be included if, in the investigator's opinion, the participant is unlikely to require initiation of thyroid hormone replacement during the course of the study. 16. Have a history of significant active or unstable major depressive disorder or other severe psychiatric disorder (e.g., schizophrenia, bipolar disorder) or other serious mood or anxiety disorder within the last 2 years Note: Participants with major depressive disorder or generalized anxiety disorder whose disease state is considered stable for the past 2 years and expected to remain stable throughout the course of the study, in the opinion of the investigator, may be considered for inclusion if th