This study is based on the assumption that muscle strength and muscle mass will be better preserved in an "intervention" group with specific management combining retraining and nutritional monitoring compared to the "no intervention" group and that this will be positive consequences for fatigue and quality of life. In addition, this project is also based on the assumption that these gains will be at least partially preserved 3 months after the end of specific care.

Cancer patients have a significant risk of losing muscle mass, mainly related to cachexia, as a result of metabolic changes associated with the tumor process and treatments. However, it is reinforced by the sedentary lifestyle that results from fatigue felt by patients. This loss of muscle mass causes in patients with general weakness and a loss of maximum strength. However, it has recently been shown that muscle weakness is not only a consequence of muscle atrophy, but also the result of contractile dysfunction, which reduces fatigue resistance to exercise. Cancer cachexia can also be directly associated with high levels of subjective cancer-related fatigue.

While it has been reported that resistance exercise programs can mitigate the deleterious effects of the disease and / or treatment, the results are likely to be partly debated because these programs are not optimized.

This study proposes to use eccentric contraction and electromyostimulation because there is evidence that the effects of these methods used in combination may be greater in developing strength and muscle mass.

In addition to muscle building, nutritional monitoring is a key element of recovery. For example, it has been shown that a preoperative exercise and nutritional support program has the potential to reduce sarcopenia and improve postoperative outcomes in elderly sarcopenic patients with gastric cancer.

Ultimately, this study is based on the assumption that muscle strength and muscle mass will be better preserved in an "intervention" group with specific management combining retraining and nutritional monitoring compared to the "no intervention" group and that this will be positive consequences for fatigue and quality of life. In addition, this project is also based on the assumption that these gains will be at least partially preserved 3 months after the end of specific care.

Inclusion Criteria:

• Patient, male or female, over 18 years old
• Patient operated on for a first colorectal cancer (adenocarcinoma) and requiring adjuvant chemotherapy
• Patient with the consent of a physician to participate in the innovative muscle building program
• Patient able to go at least once a week for 12 weeks to the Private Hospital of the Loire in Saint-Etienne (the other 2 weekly sessions that can take place in the patient's home)
• Patient affiliated or beneficiary of a social security scheme
• Patient having signed the free and informed consent

Exclusion Criteria:

• Comorbidities potentially affecting participation or test results (unstable, neuromuscular, musculoskeletal or vascular diseases affecting the lower limbs, such as radiculopathy, myopathy or neuropathy)
• Technical necessity to convert laparoscopy into laparostomy
• Patient unable to follow verbal instructions that could affect test and / or exercise procedures
• Patient participating in another clinical study
• Protected patient: major under guardianship, curatorship or other legal protection, deprived of liberty by judicial or administrative decision
• Pregnant, lactating or parturient woman
• Patient hospitalized without consent.