Evaluation of Influence of Proprietary Physical Training Program on Quality of Life, Physical Endurance, Function of Muscles and Myokines Profile in Patients After COVID-19 Infection.

The study of interventional, prospective character will be conducted in Rehabilitation Department of Medical University of Bialystok on total group of 60 participants less than 12 months after COVID-19 (coronavirus disease) infection. In all participants medical anamnesis, physical examination (including chest wall mobility), anthropometric measures, The Short Physical Performance Battery (SPPB), 6-minute walking test (6MWT six minute walking test) and treadmill stress test will be performed.

Medical history will consist of questions regarding course of COVID-19 and its consequences with special emphasis on dyspnea during daily activities in Borg scale and dyspnea in daily living in mMRC scale, coexisting diseases, treatment, lifestyle, etc. Quality of life will be assessed with use of The Short Form (36) Health Survey - SF-36), Post-COVID-19 Functional Status (PCFS] scale and Modified Fatigue Impact Scale (MFIS). Mental status will be evaluated with the use of Beck Depression Inventory (BDI) and Hamilton Depression Scale (HAMD)) Biochemical measures will be performed including, among others, myokines such as BDNF (brain-derived neurotrophic factor), adiponectin, fibroblast growth factor 21 (FGF21), resistin, myonectin and inflammatory markers, such as interleukin 6 ((Il-6), C-reactive protein (CRP).

Fasting venous blood will be collected in 2 tubes each a 10 ml, one dedicated to obtain serum ("on clot"), second with heparin) to perform biochemical analyses, In clinical evaluation measurement of respiratory (inspiratory and expiratory) muscles force with use of device MicroRPM (respiratory pressure meter), hand grip strength with use of hand dynamometer (Jamar) and strength of quadriceps muscles with use of digital dynamometer (AXIS) will be performed. During first visit also ECG (electrocardiogram), six minute walking test and treadmill stress test will be done. All patients will have diaphragm ultrasound with measurement of diaphragm thickness.

Patient will be randomized to the control and interventional groups. Control group will be subjected to the safe protocol of 6 week physical training (aerobic training, resistance training, general improvement training, stretching training and respiratory rehabilitation) adjusted to the clinical state of patients. Additionally patients will be recommended to perform a set of exercises at home under a supervision of physiotherapist.

Patients from interventional group in addition to the training protocol will be subjected to additional resistance respiratory training with the use of respiratory muscle trainer (Philips Respironics Threshold IMT). Control group will have placebo with no resistance set on respiratory muscle trainer (Philips Respironics Threshold IMT). The study will be double blind, patients will be unaware of being assigned to a group and investigators assessing functional state in the next stages of the study will not conduct rehabilitation and will not be aware of the allocation of patients to groups. Physiotherapists conducting rehabilitation will receive detailed, individual guidelines regarding the training parameters of each patient. In addition, both groups will be educated on rules of safe physical activity and how to deal with troublesome symptoms.