Effects of Post-COVID-19 on Quadriceps Femoral Muscle-tendon Unit

Effects of Post-COVID-19 on Neural Activation and Architecture of the Quadriceps Femoral Muscle-tendon Unit and Its Correlation With Inflammatory Markers

The physiological/biomechanical characteristics related to muscle and tendon architecture and their possible relationship with the loss of muscle strength and fatigue in patients who were infected with COVID-19 are totally unknown. The aim of this study is to evaluate inflammatory markers, the isometric maximum voluntary force of the knee extensor torque, muscle fatigue, neuromuscular adaptations, muscle architecture, tendinous properties of quadriceps components, oxygen extraction, and body composition in participants after diagnosis with Covid-19 who had moderate and severe levels of involvement compared to a healthy control group.

The groups will be composed of participants who had COVID-19, except for the control group, which will be composed of healthy participants who did not have COVID-19. Participants will be divided into: (1) control group, (2) COVID-19 positive participants who had moderate symptoms, (3) COVID-19 positive participants who had severe symptoms. Participants will be recruited from 21 days after the onset of symptoms, the period recommended by the scientific community that the patient no longer transmits severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). After recruitment, 4 evaluations will be carried out over 1 year.

Inclusion Criteria:

• Control group:

  - The control group will include healthy participants, aged 18 and 80 years, who had not tested positive for COVID-19.

• COVID-19 positive participants who had moderate symptoms group:

  • Female and male participants, aged between 18 and 80 years, who had Molecular test (RT-PCR) or serological test, which assesses whether the samples are reactive to immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies, positive for COVID-19;
  • Presence of some of the following symptoms, without the need for hospitalization: dry cough, runny nose, sore throat, diffuse body pain, persistent hyperthermia, no hypoxemia.

• COVID-19 positive participants who had severe symptoms group:

  • Female and male participants, aged between 18 and 80 years, who had Molecular test (RT-PCR) or serological test (which assesses whether the samples are reactive to IgM and IgG antibodies) positive for COVID-19;
  • Presence of hypoxemia (peripheral oxygen saturation - SPO2 ≤ 93%) requiring hospitalization with or without intubation, in addition to the symptoms described for the COVID-19 positive participants who had moderate symptoms group.

Exclusion Criteria:

• Body Mass Index (BMI) ≥ 35 kg/m2;
• Pregnancy;
• Pain, swelling, dermal damage, deformity, or amputation in the regions to be examined;
• Diagnosis of ankylosing spondylitis, rheumatoid arthritis, severe heart disease, advanced chronic obstructive pulmonary disease, cognitive impairment, chemical dependency, psychiatric illness, or behavioral that makes it difficult to cooperate with the procedures.