The purpose of the current study was to compare selected anthropometric and physiological parameters among bodybuilders who were virus free and continued to train (CRT) verses those who were virus free but ceased to train (HWT) and those who were infected and ceased to train (INF). Results showed that body weights of athletes infected with COVID-19 (INF) and those who ceased to train (HWT) were significantly reduced compared to healthy athletes who continued to exercise (CTR). The reduction was largerly due to significant decreases in LBM of HWT and INF compared to CTR (Table 5). Examining the components of body composition, it was noted that weight reduction was largely due to decreases in LBM in HWT and INF which did not differ significantly from each other. This agreed with Carvalho et al.  who showed that during a three-month period of no training, older women lost an average of three kilograms of body weight, which was accompanied by a reduction in function. Loss of weight might be due to infection of COVID-19 since skeletal muscle has one or more combinations of angiotensin-converting enzymes (ACE2) and transmembrane cellular serine protease type 2 (TMRRSS2) receptors that are potential targets of the virus. Second, muscles may be injured because of the increase in inflammatory cytokines . Another possible reason for these changes in body composition could be related to the side effects of treating the disease with corticosteroids such as dexamethasone and betamethasone. Commensurate with the loss of LBM, %fat in bodybuilders who ceased training (ie., HWT and INF) increased significantly compared to those who connected to train (CTR). This could be expected due to the immobility that often accompanies a lack of training.
The lack of training produced significant reductions in both upper and lower body strengths in HWT and INF compared to CRT (Table 5). Regarding upper body strength, 1RM bench press was reduced by 3.30% in HWT and 6.39% in INF compared an increase of 2.50% in CRT. In lower body strength, 1RM squat was reduced by 3.39% in HWT and 6.30% in INF compared to an increase of 2.62% in CRT. Since there is typically a direct relationship between strength and muscle mass, a major contribution to the decrease in strength can be attributed to the decrease in lean body mass. However, a decrease in neuromuscular coordination cannot be ruled out as a major factor in the decrease in strength. Desser et al.  recently reported that one of the systems involved in COVID-19 is the muscular system with a possibility of inflammation and muscle damage due to the virus. In the current study, there were signs of muscle pain in some participants during and after the acute phases of the virus. Muscle pain affects muscle motor neurons and may cause reflex inhibition that could lead to a reduction in muscle strength . In the present study, it was most probably the lack of exercise that was the major reason for the reduction in upper and lower body strengths. This is supported by previous studies that have shown reductions of 4–10% in upper and lower body strengths resulting from 4 to 12 weeks of inactivity [20–22]. Lovell et al.  believe the severity of changes during short periods of lack of training may vary depending on initial level of fitness, individual differences in response to lack of training, and age and sex of participants . In fact, even a short period of lack of training in bodybuilding athletes can cause significant changes in physiological and functional capacities . It should also be noted that the decline in physical and mental health of athletes is affected by the limitations and concerns of the quarantine period and the virus itself, especially in areas where the risks of COVID-19 and its consequent death are higher . Even though psychological profiles were not measured in the current participants, it is probable the mental state of those who did not train negatively affected their performmcne. Therefore, it seems prudent to consider the mental state of athletes returning to training following a period of inactivity due to COVID-19.
The findings of this study showed that after complete recovery from COVID-19, participants showed no symptoms of cardiovascular problems. In this regard, Metzl et al.  stated that many patients with COVID-19 who have not gone to the hospital were more likely to have no cardiac manifestations and could return to exercise safely. However, before returning to exercise, it is important to make sure that there are no persistent COVID-19-related cardiac complications . In the present study, 33% of the recovered athletes had shortness of breath during exercise in the first week. Recent guidelines recommend ten days or more of rest from onset of symptoms plus an additional seven days after symptoms resolve before returning to activity . Some studies show that recovered patients’ arterial oxygen saturation levels during exercise were below 88% . Generally, careful monitoring of respiratory symptoms and a gradual return to activity of recreational athletes suffering from COVID-19 respiratory symptoms are essential. If athletes have a history of underlying lung disease, attention to pulmonary symptoms should be emphasized.
Results of the present study showed that 50% of the recovered athletes had delayed soreness in the first week. In fact, one of the most common musculoskeletal complaints of COVID-19 is myalgia and arthralgia . Myalgia manifests as a symptom in 15% of patients with COVID-19 . Myalgia is usually self-limiting and resolves within a few days to 2 weeks. Like any viral myositis, COVID-19 myalgia care is supportive and includes heat, ice, local analgesia, and/or traction. Intense exercise should be avoided in people with muscle weakness or muscle fatigue. Acetaminophen may also be helpful in controlling pain .
Curent results also showed that a small number of recovered bodybuilders experienced gastrointestinal problems during exercising. A study evaluating 116 patients with COVID-19 found that 31.9% experienced gastrointestinal symptoms, of which 22% had nausea and vomiting and 12% had diarrhea . Also, a high percentage of these patients (22%) experienced anorexia. Primary considerations for athletes who have had gastrointestinal manifestations as part of COVID-19 include hydration and availability of energy after returning to exercise after medical treatment . The fluid and calorie intake of athletes should be monitored at all symptomatic stages of the disease, as well as the resolving of symptoms after returning to activity.
Returning to exercise should take into account the type of activity and should occur about two weeks after improving symptoms . Participants in the current study had experienced no symptoms for two weeks and had lack training for four weeks from the infection period until their negative PCR test. Although accurate instructions for returning athletes to sports activities are very limited , one study has reported the best time to be more than ten days from the onset of symptoms . However, there is a need for additional research for athletes. The intensity of exercises has operatively been set at about 60% in the first week to reduce the risk of injury due to lack of training and decondition [30, 31].
In summary, absence of training whether due to lack of facilities or viral infection is likely to reduce muscle mass and strength performance in weightlifters. Due to the possible infection of the pulmonary airway, it is recommended that the training of athletes who have recovered from coronavirus be closely monitored for at least two weeks so that medical actions can be promptly implemented if necessary.