The Effect of 12-week Circuit Training on Insulin Sensitivity and Endothelial Function in Women With Insulin Resistance

The training program will be performed on 7 machinesin a circuit. The devices will be controlled by a pre-programmed chip card, so that they will automatically adjust their parameters, such as seat height or resistance to the patient, and it will be possible to monitor the training progress of exercising women and their presence during training. Only two people will be allowed in the room during the training. The planned duration of the exercises will be controlled (one minute for strength exercises, four minutes for endurance exercisesand a 30-second break between each exercise) and for each trainee the load will be dosed using the electronic resistance motor system. Exercises in the training program are planned in such a way that the different muscle groups of women exercising are loaded alternately, which will ensure comprehensive training of the whole body. The range of movement, exercise duration and breaks will be controlled automatically by the system and the software of the devices and will not require additional training attention.

In the training group, one-repetition maximum exercise test (1RM) will be performed to determine the appropriate training load and later after the program to verify the increase in muscle strength.

The HR max range will be determined for exercising women by the indirect method using the formula: training HR = 220 -subject age.

The characteristics of exercises in the circuit:

• The training circuit starts with an exercise on a cycloergometer -"bike", which lasts 4 minutes.
• The second exercise -"abdominal crunch", shapes the strength of the abdominal muscles and together with exercise number six, it not only improves muscle strength parameters, but also shapes balance and maintains the correct position of the body.
• The third exercisein a circuit-"leg curl", shapes the muscular strength of the back of the thigh (biceps femoris muscleand muscles adjacent to it).
• The fourth exercise -"lat pulldown", trains the strength of the latissimus dorsi muscle, shoulder girdle muscles and upper chest. In addition to improving the strength and function of the muscles mentioned above, the exercise also perfectly stimulates the auxiliary respiratory muscles.
• Fifth exercise -"crosswalker".This exercise trainsmost of the body's muscles, itlasts 4 minutes and, like training on a cycloergometer, primarily shapes thephysical capacity.
• The sixth exercise -"back extension"trains the strength of the abdominal muscles, erector spinae and other muscles of a back.
• The seventh exercise -"legabductor", the last in the series, is an exercise that shapes the gluteal muscles, as well as hip adductor and abductor muscles. This exercise fulfills the function of shaping strength and securing the hip joint, by training the muscle parts less frequently used in everyday life, the more difficult to be kept fit as the years go by and the level of physical activity decreases.

Inclusion criteria

• women,
• age: 25-45years,
• menstruating,
• BMI 18,5-29,9 kg/m2,
• insulin resistance based on HOMA -IR (cut-off point 2.5),
• not contraindicated to physical activity.

Exclusion criteria

• type 1 and 2 diabetes,
• poorly controlled hypertension (mean SBP >140mmHg and/or mean DBP >90mmHg) over the last month and/or need to modify the pharmacological treatment,
• obesity: BMI > 30 kg/m2,
• lipid disorders requiring implementation of pharmacological treatment in the last 3 months before or during observation,
• a positive history of ischemic heart disease, carotid atherosclerosis and / or lower limb atherosclerosis,
• clinically significant arrhythmias or conduction disorders,
• chronickidney disease,
• clinically significant liver dysfunction,
• acute or chronic, clinically manifest inflammatory process,
• an acute infection in the last month,
• cancer,
• taking dietary supplements within a month before inclusion and during observation,
• taking medication that could interfere with the results of the tests,
• other conditions that may pose any risk to the patient during the observation.