Long-term effect of non-severe COVID-19 on pulmonary function, exercise capacities and physical activities: a cross-section study in Sakaka Aljouf

Background COVID-19 has serious consequences on different body systems particularly the respiratory system with its impact on pulmonary function, exercise capacities, and physical activities. This study aimed to investigate the long-term effect of COVID-19 on pulmonary function, exercise capacities, and physical activities in patients with non-severe COVID-19. Methods 160 individuals were selected to participate in a cross-section study. Group-I: 80 male and female patients with non-severe COVID-19 at least 3 months after the recovery time. Group-II: 80 male and female matched (non-infected with COVID-19) participants. The spirometer, six-minute walk test (6MWT), and International Physical Activity Questionnaire (IPAQ) were used to assess pulmonary function, exercise capacities, and physical activities respectively. The Kolmogorov-Smirnov test was used to test normality of data. The Mann–Whitney and independent t-tests were used to compare the significant differences between both groups. Results The results show significant differences in FVC & FEV 1 of the pulmonary function, exercise capacities, and physical activities of the work & transportations between both COVID-19 and matched groups p-value = (0.001 & 0.001, 0.001 and 0.005 & 0.012) respectively. Conclusion Pulmonary function, exercise capacities, and physical activities are negatively influenced by COVID-19 as long-term consequences indicating the need for extended health care, and prescription of proper rehabilitative training programs for non- severe COVID-19 patients whatever their severity degree of infection or history of hospitalization. Outcome reflections of the current results raise awareness of physical therapists to the importance of the proper rehabilitative training programs for non-severe COVID-19 patients.


Introduction
Coronavirus disease 2019 (COVID- 19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which began spreading on 31 December 2019 and had spread globally in the first months of 2020. 1 Although many patients with COVID-19 do not suffer from any symptoms and recover spontaneously without medical interventions, one in every six patients develops breathing difficulties and becomes seriously ill. 1 Until 29 September 2022, there had been 613,942,561 confirmed cases, including 6,520,263 deaths worldwide due to COVID-19. 2 Public health was forced to take specific protocols to prevent rapid spread of pandemic, and its associated economic crisis. 3Tens of millions lost their jobs and increased poverty levels. 4Consumption, investments, 5 work absenteeism, productivity, and hospitality sectors all impacted negatively on income and supply. 5,6COVID-19 affects people of all ages and seriously impacts different body systems. 7st-COVID-19 syndrome means the sequelae that develop during or after a SARS-CoV-2 infection and persist for more than 12 weeks. 8It encompasses multi-organ sequelae beyond the acute phase which ranges from physical and cognitive abnormalities to functional limitations, exercise impairments and deterioration of quality of life. 9,10 The pulmonary and cardiovascular systems are the most important impacted organs with their reflections on patient's physical activities, and quality of life.Similar coronavirus infection (SARS-CoV) caused its impairments for two years which are expected to occur for the survivors of COVID-19. 13COVID-19 causes marked impairments in the diffusing lung capacity for carbon monoxide (DLCO), total lung capacity, forced expiratory volume in one second and forced vital capacity ratio (FEV 1 /FVC), restrictions in small airways, 14 -16 restrictive and obstructive patterns of the pulmonary function, 15 low quality of life 15,16 consolidation patterns, 17 restrictions in both the two minute walking test (2MWT) and FVC, 17 respiratory muscles dysfunction and lung fibrosis, 18,19 in addition to formation of pneumocytes. 20Middle East respiratory syndrome (MERS) and SARS are the two previous viral infection outbreaks like the current COVID-19. 20Abnormalities of the lung function are classified to obstructive pattern, restrictive pattern, and small airway disease. 21COVID-19 patients with cardiovascular and pulmonary comorbidities are more vulnerable to hospitalization, 22,23 and for developing neurological events, e.g., acute cerebrovascular disease, conscious disturbance, and skeletal muscle injury. 19Even though vaccination against COVID-19 can prevent hospitalization and severe infection.It has been adequate protection only against some long-COVID-19 symptoms, including cognitive dysfunction, sleeping disorders, and kidney diseases. 24Even after recovery of survivors of COVID-19, almost 10-20% may suffer long-term consequences including fatigue, dyspnea, and impairments in both cognitive and daily functions. 7Also, COVID-19 patients may be complicated with bladder dysfunction, severe urinary symptoms, [25][26][27] higher liver enzymes, 28 gastrointestinal symptoms, 29 psychotic disorders 30 and poly-neuromyopathy. 31wever, there were restrictions in the physical performance, activities, and the detected impairments in sleep quality at 12 weeks post-COVID-19 infection. 32Although time of walk improved significantly at the sixth month of recovery it still reduced on comparison with that spent before COVID-19 for the same patients, 33 also, the physical activities and the oneminute standing test were impaired at discharge of patients with COVID-19. 34Evidence of persistent physiological and radiographic changes is available in most patients who recovered from severe COVID-19. 35Patients with persistent dyspnea had several abnormalities during the 6MWT e.g., greater restriction on spirometry, reduced exercise capacity and increased exertional symptoms. 36As a result of wide variations in epidemiology and treatment for long-term sequels of COVID-19, it is considered a new area of research. 7,37,38There is need for more studies to investigate effects of COVID-19, particularly its long-term impact on the pulmonary function, physical activities, and exercise capacities.The authors mainly concentrated in previous studies on investigating critical hospitalized survivors and who experienced severe infection, 19,[39][40][41] whereas Non-severe COVID-19 survivors might be ignored during the pandemic so; further research is recommended particularly for those patients with mild and moderate degree of COVID-19. 32,33Therefore, the current study aimed to investigate long-term effect of COVID-19 on pulmonary function, exercise capacities and physical activities in patients with non-severe degree after three months from recovery time.

REVISED Amendments from Version 4
The amendment in version 4 of our manuscript includes only changing the writing style of the interquartile range (IQR) in table 1 and table 2. Any further responses from the reviewers can be found at the end of the article

Design of the study
A cross-section study.

Ethical approval
All procedures of the study were approved by the Ethics Research Committee of the Institutional Review Board of Imam Abdualrahman bin Faisal University (IRB-PGS-2021-03-427).Also, by the Research Ethics Committee in Qurayyat Health Affairs, Ministry of Health, Project no: 083, Saudi Arabia.This study was conducted in accordance with the Declaration of Helsinki at the out-patient clinic of the Physical Therapy Department of King Abdulaziz Specialist Hospital in Sakaka Aljouf, Ministry of Health-Saudi Arabia between September 2021 to June 2022.Prior to participation, all participants signed a consent form, and they were informed that the collected data would be submitted for publication.Subjects 600 participants were screened from the department of pulmonology and out-patient clinic of the Physical Therapy Department, King Abdulaziz Specialist Hospital in Sakaka Aljouf.They were assigned to, COVID-19 group: 80 male and female patients (After physical examination, inspection and analysis and reports of analysis checking by pulmonologist) with confirmed non-severe COVID-19 at least 3 months from recovery time.Recovery is being free from fever and respiratory symptoms for at least 3 days followed by two negative polymerase chain reaction (PCR) tests 24 hours apart, or if PCR was not available, resolution of the clinical manifestations for 3 days and at least 10 days have passed from the appearance of the first symptom. 43Matched Group: 80 male and female matched participants (non-infected with COVID-19, their PCR was negative for COVID-19, no signs, or symptoms of infection) who were invited to participate as control group.

Inclusion criteria
Male and female patients who diagnosed with mild & moderate COVID-19 after three months from recovery time and matched non-infected with COVID-19 participants, their age ranges from 25 to 55 years.

Exclusion criteria
[46] Procedure of the study Demographic data were recorded including weight, body mass index (BMI), oxygen saturation, heart rate, blood pressure, comorbidities, admission to the intensive care unit or hospitalization, severity degree of infection was determined with pulmonologist according to the classification of WHO progression scale. 47This scale classifies severity of COVID-19 infection into five categories: 1-Uninfected with a 0 score, 2-Mild disease with a score ranging from 1-3, patient is asymptomatic with detected viral RNA or symptomatic with assistant needed, 3-Moderate disease with a score ranging from 4-5, patient is hospitalized and not need for oxygen therapy or hospitalized and need for oxygen therapy or non-invasive ventilation, 4-Severe disease with a score ranging from 6-9, patient is hospitalized and need for oxygen therapy by non-invasive ventilation or high flow, 5-Dead with score 10.
All participants underwent these outcome measures: a) Pulmonary function was measured by using the Spirobank II spirometer (Medical International Research, USA, Inc., www.spirometry.com).It is a validated device used for diagnosing and evaluating pulmonary diseases. 48he lung function are classified according to the American Thoracic Society as: normal, if both FVC and the FEV 1 /FVC ratio are in the normal range; obstructive pattern, if FEV 1 /FVC ratio is <70% of the normal predicted value and FEV 1 <80% of the predicted; restrictive pattern, if FEV 1 /FVC ratio is ≥70% of the normal predicted value, and the total lung capacity <80% of the predicted value.If total lung capacity is not available, a reduction in the FVC <80% of predicted is considered as a restrictive pattern, small airway disease, if forced expiratory flow between 25% and 75% of FVC (FEF 25-75% ) is <65% of predicted value. 21All participants underwent the test according to guidelines of the American Thoracic Society and European Respiratory Society (ATS/ERS). 46he obtained parameters are FVC, FEV 1 , FEV 1 /FVC ratio, FEF 25-75% , and peak expiratory flow (PEF).All measurements of pulmonary function testing (PFT) were expressed as absolute and percentage of predicted normal values (% predicted), the percentage of predicted normal values was calculated automatically based on age, sex, height, and ethnicity. 49Each participant completed three accepted maneuvers and the highest value was recorded and used in the statistical analysis.
b) Physical activity was measured by using the International Physical Activity Questionnaire (IPAQ-Arabic version) which is valid and reliable. 50It assesses physical activity during the last seven days throughout four domains: work-related physical activity, transportation-related physical activity, domestic and yard, and leisure time physical activity.Every participant was asked to answer each question in all domains.The scores are calculated for each domain and expressed as metabolic equivalent minutes per week (MET-minutes/week).The total physical activity score is calculated by summating the total scores for all domains, the physical activity score is classified into high, moderate, and low as 3000,600 and <300 MET minutes/week respectively. 51c) Exercise capacity was measured by using the 6MWT: It is valid and reliable, and it has been approved to estimate sub-maximal exercise performance, daily physical activities, 52 and endurance in older adults [53][54][55] and post-COVID-19 patients over 18 years. 39Each participant was asked to walk independently with his or her comfortable footwear on a flat, well illuminated, non-slippery ground surface in corridor 30-meters space for 6 minutes as fast as possible without oxygen support, the results were expressed in meters. 52 Pulse oximeter is a valid and reliable device; a wearable wrist oxygen pulse oximeter was well fastened in the index and wrist of the non-dominant hand to detect oxygen saturation and heart rate for every participant during 6MWT.56 e) Modified Borg Scale of Dyspnea is a scale rated from 0 to 10.It was used to monitor severity of self-reported breathlessness during the 6MWT.57

Statistical analysis
The collected data were analyzed using SPSS statistical software (version 25) and were tested for normality using the Kolmogorov-Smirnov test.Group comparisons were done using independent t-test and Mann-Whitney test for normal and not normal data distribution respectively.The Chi-squared test was used to compare the categorical variables.The COVID-19 group was divided into pre-6 months and post-6 months sub-groups to determine time effect on the associated consequences, these two sub-groups were compared descriptively with the matched group by using the confidence intervals.Statistical significance was set at P-value <0.05 with a confidence interval of 95%.
The COVID-19 group was divided into pre-6 months and post-6 months sub-groups to investigate the time effect on post-COVID-19 consequences.The results of pulmonary function, four domains of the IPAQ and 6MWT of COVID-19, pre-6 months and post-6 months groups were descriptively compared by using the confidence intervals at 95% (Table 3).
The results of pulmonary function, domains of the IPAQ and the 6MWT distance showed non-significant differences on comparison of pre 6 months with the post 6 months groups (except the predicted FVC P-value <0.05).IQR: Interquartile range (is the range of the middle 50% of the data set).b Mann Whitney test was used to determine significant differences between two groups for not normal distributed variables.c Independent t-test was used to determine significant differences between two groups for normal distributed variables.*Significantly difference P-value < 0.05.FEF 25-75% of pred: forced expiratory flows at 25-75% of FVC percentage of predicted, FEV 1 % of pred: Forced expiratory volume in the first second percentage of predicted, FEV 1 /FVC% of pred: forced expiratory volume in the first second and forced vital capacity ratio percentage of predicted, FVC% of pred: forced vital capacity percentage of predicted, PEF% of pred: peak expiratory flow percentage of predicted, 6MWT: Six minute walking test.In contrast to our results the findings of Lerum et al. show normal pulmonary outcomes including lung function, 6MWT distance, oxygen saturation, dyspnea prevalence measured at the third month after hospital discharge. 60Also, Eksombatchai et al. found non-significant differences in the pulmonary function of mild and moderate survivors COVID-19 with pneumonia. 61The authors highlighted the absence of PFT data for their patients' samples prior to occurrence of COVID-19. 40,62e underlying mechanisms for COVID-19 multiple findings may be due to acute lung injury with diffuse alveolar damage which is associated with fibrotic changes and microthrombi in the pulmonary vasculature. 63The restrictive impairment of the lung function may be caused by fibrotic changes in the lung and increase proinflammatory cytokines which recruit fibroblasts resulting in lung fibrosis. 64The decline in pulmonary function results from the respiratory muscles fatigue as a significant improvement of PFT after pulmonary rehabilitation for COVID-19 survivors, 65 the results of PFT are also influenced by several factors e.g., sex and body type. 66r findings show significant reductions in measured parameters of pulmonary function, 6MWT distance and domains of physical activities in patients with COVID-19 after 3 months, on comparison with the matched group.There are progressive improvements on comparison of pre with post 6 months sub-groups as a time effect and being non-significant may be due to patients' sample of pre 6 months was not the same patients' sample of post 6 months.The current results are consistent with findings of Magdy et al. determined lower limits in lung function (<80%) and non-statistically significant differences in the pulmonary function at 3 and 6 months post-infection. 67Whereas existing significant improvements at one year follow-up. 59This finding does not contradict with our results as they compared the same patients at 3 months, 6 months and after one year not the case in the current study where the patients' sample was descriptively compared at pre 6 months and after 6 months to matched control.Also, Zhang et al. found 20% of the survivors of COVID-19 had FEV 1 / FVC below 70% of predicted values at the eighth month. 62e current results contradict the findings of Wu et al. as they found significant increases in pulmonary function at 3, 6, 9 and 12-month interval measures post-infection (time effect) 35 this may be also due to the authors did the interval assessments for the same COVID-19 patients.They found high rate of dyspneic patients (81%) measured at the third month whereas it was 21% in the current study.This may be their sample included only severe COVID-19 patients whereas the sample in the current study included both mild and moderate degree of COVID-19.Also, Madrid-Mejía et al. determined improvements in PFTs at the sixth month of infection compared to the results of the same participants at the third month after infection. 68The variations in the time of evaluation in different studies may explain the differences in the results. 15,40,69 our study, despite the result of the exercise capacities (6MWT distance) show significant reductions in the COVID-19 group after 3 months, from recovery on comparison with the matched control, there are non-significant increases at both pre and post 6 months.This finding is consistent with the results of Magdy et al. who determined significant reductions in the 6MWT results of the survivors of COVID-19 on comparison with the normative data, 40 whereas a significant improvement was determined in the 6MWT at the sixth month in regarding the third-month follow-up. 40They referred their findings to the extended period of hospital stay and extra usage of corticosteroids which could influence the muscles resulting in muscle wasting and myopathy. 40,70,71Also, Calabrese et al. demonstrated significant reductions in the FVC %, DLCO, low oxygen saturation (Sp O2 ) (>90%) during the 6MWT with higher dyspnea. 41In addition, Raman et al. found significant reductions in the distance of the 6MWT for COVID-19 patients on comparison with controls. 72hey referred this limited exercise capacity to muscle wasting that caused by the catabolic state resulting from severe illness, and potentially inflammation. 72 -74While Abdallah et al. reflected the persistence of breathlessness and limitation in exercise capacity at the third month to the residual defects in TLC. 58In addition, the recovery of the physical function within the first 6 months of patients after SARS-COV was incomplete as it lasts for one to two years. 13In addition, Magdy et al. found significant increases in the 6MWT distance at the 6-month follow-up. 67Accordingly, the lower results of the 6MWT distance may be attributed to the higher BMI, and high number of female participants in the current study.The distance of the 6MWT is negatively influenced by sex and body type. 52On contrary to the current findings Wu et al determined significant improvements in the 6MWT at 3, 6, 9, and 12-month interval measures post-infection. 35r results agree with the findings of Belli et al. they found patients with COVID-19 suffer from impairments in physical functions and fitness, as 33.3% of patients had impaired physical fitness, and 17.5% with moderate scores in activities of daily livings performance. 75Cao et al. also stated that performance in the 6MWT was significantly lower in post COVID-19 patients than in health controls. 76Lower performance in the 6MWT was reported in patients with severe/ critical COVID-19 compared to patients with mild/moderate disease at baseline. 77On contrary to the results of the current study the findings of Lerum et al. they concluded non-significant differences in the results of the 6MWT between ICU and non-ICU groups and Eksombatchai et al. they found statistically typical results for the 6MWT among three groups, while the severe infection group showed lower results when compared with the mild and moderate infection groups but not statistically significant. 60,61The results of oxygen saturation show non-significant differences (p = 0.201) among groups for both pre and post 6MWT.They referred the reductions in their results to the higher BMI and older age in the severe group. 60,61 the current study, the results of the IPAQ significantly reduced in all domains in the COVID-19 survivors' group on comparison with the matched group after 3 months.The current findings are supported with the results of Tanriverdi et al. found poor physical activities and impaired hand grip power at least three months of survivors of COVID-19. 32Paneroni et al. who determined impaired physical activities at the discharge time. 34As a result of improvements in physical activities with time effects on comparing survivors of COVID-19 of pre and post 6 months with the matched controls, descriptive differences were determined in some IPAQ domains.Also, the current findings supported the findings of Delbressine et al. who found significant improvements in physical activities in the survivors of COVID-19 at the sixth month compared with results at the third month post-infection. 33In the current study, the IPAQ questionnaire was used to assess the physical activities during the last seven days only, which may not give an accurate perception of the physical activities as it could be affected by other factors e.g., the work domain could be lower for some participants because they were on vacation for the last seven days.The transportation domain may be lower for some patients because they must use vehicles due to the hot weather.Some participants did not have gardens or backyards, which reduces their domestic and yard scores.Other participants may have lower leisure time domain scores because they did not feel well to walk or did exercise during the last seven days in convalescent stage.Although the current results of outcome measures show significant reductions in pulmonary function, physical activities, and exercise capacity after 3 months, on comparison to matched participants there are general progressive improvements as time effects but still patients with COVID-19 need to extend their health care and to prescribed proper rehabilitative training programs whatever their severity degree of infection or history of hospitalization.

Limitations
There was a lack of data on health conditions of patients prior to contracting COVID-19 so the authors tried to overcome this limitation by including a matched control group, small sample size, usage of simple spirometry approach, lack of DLCO and plethysmography.Despite these limitations, the authors believe that the results of this study contribute to filling a significant knowledge gap about consequences of COVID-19 after 3 months of recovery time.

Recommendations
Further studies to investigate effectiveness of COVID-19 long-term complications and follow-up for patients with different severity of infections and effectiveness of individualized comprehensive rehabilitative programs for such patients.

Conclusion
Pulmonary function, exercise capacities, and physical activities are negatively influenced by COVID-19 as long-term consequences indicating the need for extended health care, and prescription of proper rehabilitative training programs for those patients whatever their severity degree of infection or history of hospitalization.Gaining the deepest knowledge and awareness that enables physical therapists how to tailor the appropriate rehabilitative training programs for non-severe COVID-19 patients.

Sample size:
By calculation, it was estimated to be n=73 in each group.Then, why n=7 samples were added to each group?It is unethical to utilize 14 human valuable times when the same could have arrived without including them.Please justify.

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Procedure of the study: c) Functional capacity was measured by using the 6MWT: "without oxygen inhalation" is not correct.It should be changed to, "without oxygen support or assisted ventilation".

Results:
Figure 1 -Still Not correct.In a cross-sectional study, how is dropout possible?Please remove the word, "Dropout" from, Figure 1 ○ In Table 1 to Table 4, if the data does not follow normal distribution, then it should be expressed as a median with interquartile range (IQR) or geometric mean with 95% confidence interval.Mean with SD is not appropriate.Modify accordingly.Even expressing in 95% confidence interval is not appropriate.Moreover, the way of representing 95% confidence interval is not correct.Table 4 is not necessary.Why have to express it in Mean with SD which is not appropriate?
○ the same could have arrived without including them.Please justify.

Response 1-
The sample size is considered the minimum number of participants must be included till the results analysis and statistical outputs to be valid and reliable, so the extra numbers make our results more valid and reliable.2-The calculated sample size gives us an estimation of the minimum sample size,so maximizing the sample size is healthy.Sample sizes are calculated to detect the smallest clinically significant difference.to detect the smallest clinically significant difference, it has more than adequate power to detect bigger differences.https://www.ndi.org/sites/default/files/samplesizecalculation.pdfpage 17 3-Overestimating the same size could be done to minimize the effects of a few participants' incomplete data which is removed from analysis.

Second comment
Functional capacity was measured by using the 6MWT: "without oxygen inhalation" is not correct.It should be changed to, "without oxygen support or assisted ventilation".

Response
The statement is rephrased to Functional capacity was measured by using the 6MWT without oxygen support.

Third comment
Figure 1 -Still Not correct.In a cross-sectional study, how is dropout possible?Please remove the word, "Dropout" from, Figure 1 In Table 1 to Table 4, if the data does not follow normal distribution, then it should be expressed as a median with interquartile range (IQR) or geometric mean with 95% confidence interval.Mean with SD is not appropriate.Modify accordingly.Even expressing in 95% confidence interval is not appropriate.Moreover, the way of representing 95% confidence interval is not correct.3rd Paragraph -Finally, our recommendations for solution should be described, in other words our aim should be communicated.When these steps are followed in that order, the reader can track the problem, and its solution from his/her own perspective under the light of current literature (what are you going to do?).
○ By calculation, it was estimated to be n=73 in each group.Then, why n=7 samples were added to each group?It is unethical to utilize 14 human valuable times when the same could have arrived without including them.Please justify.

Subjects:
(based on external examination of body characteristics) -reference or details to be added.

Inclusion criteria:
Male and female patients who diagnosed with mild & moderate COVID-19 -Define "mild COVID-19" and "moderate COVID-19" or add the reference for the same.

○
Procedure of the study: c) Functional capacity was measured by using the 6MWT: "Each participant was asked to walk independently on flat ground" -describe the nature of the flat ground like, nonslippery, well illuminated, etc, and walk with footwear or without footwear.
○ d) Pulse oximeter -how was the pulse oximeter held -fastened to the fingers or any other part while walking as fast as possible?Add the practical issues that might help in replicating the study in the future.

○
In Table 1 to Table 5, if the data does not follow normal distribution, then it should be expressed as a median with interquartile range (IQR) or geometric mean with 95% confidence interval.Mean with SD is not appropriate.Modify accordingly.Moreover, Table 4 and Table 5 have duplicated values which were already presented in Table 3. Avoid this duplication.Tables 3-5 could be merged.

Discussion:
Add strengths of the study.

Conclusion:
Conclude regarding, non-severe COVID-19 and Sakaka Aljouf.These are two key facts to be added.

○
The comments of the second reviewer and responses of the authors.My grateful thanks for the your valuable and important scientific comments, all of theses comments are considered.

Abstract:
Background: The words physical activities were only used in the text and the words physical performance were omitted "Retain either, "physical activities" or "physical performance".
This statement was rephrased in all manuscript to pulmonary function, exercise capacities, physical activities.

Avoid duplicating similar words, "pulmonary function, functional capacities, physical activities" in the same paragraph.
This statement was rephrased in all manuscript to pulmonary function, exercise capacities, physical activities.
The statement was rephrased to 80 male and female matched (non-infected with COVID-19) participants.
The Shapiro-Wilk's test was changed to Kolmogorov-Smirnov test.
As the sample size is >50, Shapiro-Wilk's test will not be appropriate to test the normality of data.Kolmogorov-Smirnov test would be more appropriate.
The Shapiro-Wilk's test was changed to Kolmogorov-Smirnov test.

Introduction:
Introduction The introduction was rephrasing again including 4 paragraphs.Its length was adjusted as I organize the introduction into 4 paragraphs.
The first one talking about the prevalence and hazards of COVID-19 as this is new research area.
The second and the third included the pathology of COVID-19 and its impacts on different body systems.
The last paragraph or the fourth explains gap of knowledge and objective of the study.Overall, the introduction is lengthy.Generally, the introduction should be 10% to a maximum of 20% of the total manuscript length.
It was done.
By calculation, it was estimated to be n=73 in each group.Then, why n=7 samples were added to each group?It is unethical to utilize 14 human valuable times when the same could have arrived without including them.Please justify.
The sample size is considered the minimum number of participants or number of patients must be included till the results analysis and statistical outputs to be valid and reliable, so the extra numbers make our results more valid and reliable.
The extra or exceeding number of sample sizes do not conflict with the ethical aspects particularly our study is a cross sectional study the attendance of patients included only two times.
The measured variables do not have any hazards for participants, also are valuable and worthful for patients and matched participants to know their results of their assessments.

Subjects:
(based on external examination of body characteristics) -reference or details to be added.
After physical examination, inspection and analysis checking by pulmonologist to confirm their diagnosis they were infected with COVID -19, and their conditions are classified as mild and moderate not severe according to WHO severity Scale.

Inclusion criteria:
Male and female patients who diagnosed with mild & moderate COVID-19 Define "mild COVID-19" and "moderate COVID-19" or add the reference for the same.
Definition of Mild and moderate COVID-19 was added in the paragraph of procedure of the study with also its reference.
Define "severe COVID-19" or add the reference for the same.
Was added in the paragraph of procedure of the study with also its reference.
Procedure of the study: c) Functional capacity was measured by using the 6MWT: "Each participant was asked to walk independently on flat ground" -describe the nature of the flat ground like, non-slippery, well illuminated, etc, and walk with footwear or without footwear.
The statement is rephrasing with addition of some explaining important words as Each participant was asked to walk independently with his or her comfortable footwear on a flat, well illuminated ,non-slippery ground surface in corridor 30-meters space for 6 minutes as fast as possible without oxygen inhalation, the results were expressed in meters.
d) Pulse oximeter -how was the pulse oximeter held -fastened to the fingers or any other part while walking as fast as possible?Add the practical issues that might help in replicating the study in the future.
The statement was rephrased.A wearable wrist oxygen pulse oximeter was well fastened in the index and wrist of non-dominant hand for every participant to measure oxygen saturation during 6MWT.After your suggestion and opinion and also consultation of statistician he agreed with your opinion the sample size of matched group, pre-6 months group and post -6 months group are different, so they only compared descriptively by using confidence intervals.And the Kruskal-Wallis's test was canceled.

Results:
Figure 1 -Not correct.In a cross-sectional study, how is dropout possible?Please justify.
As the study procedure was done by attendance of participants in two-days first day to determine the proper participants who meet inclusion criteria of the research and taking the demographic data the second day for taking different measurements, some of them are already selected and take his or her demographic data but not attend in the second day for doing measurements.
In Table 1 to Table 5, if the data does not follow normal distribution, then it should be expressed as a median with interquartile range (IQR) or geometric mean with 95% confidence interval.Mean with SD is not appropriate.Modify accordingly.
The mean and standard deviation was replaced with median and IQR .
Moreover, Table 4 and Table 5 have duplicated values which were already presented in Table 3. Avoid this duplication.Tables 3-5 could be merged.
It was done as the Kruskal-Wallis's test output was cancelled and table 5 was deleted.

Discussion:
Add strengths of the study.
Was explained and clarified in different points as rephrasing gap of knowledge, used objective assessment equipment , discussion and conclusion

Conclusion:
regarding, non-severe COVID-19 and Sakaka Aljouf.These are two key facts to be added.

Was done.
Finally thanks for your worthful comments.
Competing Interests: No competing interests were disclosed.Evaluations of the pulmonary variables (using the spirometer), the physical capacity (using the sixminute walk test), and the physical activities variables (using the International Physical Activity Questionnaire) were done for both groups.
Results showed significantly reduced pulmonary, functional capacity and physical activities levels (at least 3-months post-Covid-19 recovery) in patients affected with COVID-19 (group-I) compared with healthy matched participants (group-II).

Abstract:
Background: "Personal performance": better to change it to "physical performance".

○
Results: "The results show significant differences in…", please provide the means and SD as well as pvalues.

Conclusion:
The sentence "whatever their severity degree of infection or history of hospitalization": It is better to modify this sentence or remove it since the current study is limited to mildmoderately affected patients and did not provide full details regarding the history of hospitalization.

○
The sentence "reflections of the current results raise awareness for physical therapists to tailor the proper rehabilitative training programs for such patients": it is better to add "on long term-basis" at the end of the sentence.

Introduction:
Abbreviations (e.g., 2MWT, FVC and so on) need to be written first in full term, then to be abbreviated after that within the text.

Results:
Were there correlations between the severity and duration post COVID-19 infection on one hand and the evaluated variables on the other hand?

○
The word "sex" is better to be replaced with "gender".

○
In table 4 and 5; please provide the numbers of participants in each group.Abbreviations (e.g., 2MWT, FVC and so on) need to be written first in full term, then to be abbreviated after that within the text.

Methods:
Inclusion criteria: Please provide more details about the Non-sever COVID-19 as it is the main inclusion criteria (at least add "who diagnosed with mild-moderate COVID-19).
Author Response: The patient sample was selected by pulmonologist.The severity of the infection was classified according to the WHO regression scale (Marshall et al., 2020).The scale classifies the severity of COVID-19 infection into five categories: 1-uninfected with a 0 score, 2-a mild disease with a score ranging from 1-3, 3-a moderate disease with a score ranging from 4-5, 4-a severe disease with a score ranging from 6-9, and 5-dead with score 10.

Author response:
The covid group was selected at least 3 months from recovery after that they are classified into two groups, pre 6 months, & post 6 months after recovery time.

Results:
Were there correlations between the severity and duration post COVID-19 infection on one hand and the evaluated variables on the other hand?
The word "sex" is better to be replaced with "gender".In table 4 and 5; please provide the numbers of participants in each group.

Author Response:
The spearman's correlation with the severity of infection showed that positive correlation between 6 MWT physical activity transportation, and physical activity domestic &yard (r= 0.005 &0.03 respectively also presence of positive correlation between FEF a & FEF 25-75 (r= 0.042) , While the results show negative correlation BMI & physical activity transportation & leisured and free time (r= 0.015 &0.012) respectively whereas presence of positive correlation between 6MWT & FEV1 (r= 0.014).
In addition to time factor the results show negative correlation between BMI & both physical activity of work and transportation (r= 0.015&0.027and 0.001&0.046) in pre 6 months and post 6 months subgroup respectively .The number of patients was written in the statistical part pre-6 months (30patients) and post 6-months(50 patients) sub-groups The word "sex" was replaced with "gender".

Discussion:
Please correct the following sentence: "Results of the current study indicate that post-COVID-19 patients may experience chest abnormalities including reductions in pulmonary function, decreased functional capacity, and physical activities up to one year after recovery time".Since the average post COVID-19 duration of this study is 7.9 months.

Author Response:
Results of the current study indicate that post-COVID-19 patients may experience chest abnormalities including reductions in pulmonary function, decreased functional capacity, and physical activities within the average time 7.9 months after recovery Thanks for your valuable comments.
Competing Interests: No competing interests were disclosed.
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Figure 1 .
Figure 1.Flow chart of the participants' recruitment.
BASE DE DATOS EVALUACIÓN SENSORIAL 24 05 2023.xls(Data for tastings carried out with students.The samples were 4 cereal bars made with cereal grains and with different percentages of ant flour.)Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).

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1st Paragraph -Provide information about the general topic of the article in the light of the current literature which paves the way for the disclosure of the objective of the manuscript (what is known?).

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2nd Paragraph -Focus on the specific subject matter, and the issue to be focused on should be dealt with, the problem should be brought forth, and fundamental references related to the topic should be discussed (what is unknown?).

Figure 1 -
Not correct.In a cross-sectional study, how is dropout possible?Please justify.
should be drafted in 3 paragraphs.Please refer to this article for detailed description: Armağan (2013 1 ).1st Paragraph-Provide information about the general topic of the article in the light of the current literature which paves the way for the disclosure of the objective of the manuscript (what is known?).2nd Paragraph -Focus on the specific subject matter, and the issue to be focused on should be dealt with, the problem should be brought forth, and fundamental references related to the topic should be discussed (what is unknown?).3rd Paragraph -Finally, our recommendations for solutions should be described, in other words our aim should be communicated.When these steps are followed in that order, the reader can track the problem, and its solution from his/her own perspective under the light of current literature (what are you going to do?).
Please correct the following sentence: "Results of the current study indicate that post-COVID-19 patients may experience chest abnormalities including reductions in pulmonary function, decreased functional capacity, and physical activities up to one year after recovery time".Since the average post COVID-19 duration of this study is 7.9 months.○Is the work clearly and accurately presented and does it cite the current literature?YesIs the study design appropriate and is the work technically sound?YesAre sufficient details of methods and analysis provided to allow replication by others?YesIf applicable, is the statistical analysis and its interpretation appropriate?PartlyAre all the source data underlying the results available to ensure full reproducibility?Yes Are the conclusions drawn adequately supported by the results?Introduction:

Table 2 .
Mean values of PFT, 6MWT and IPAQ of COVID-19 and control matched groups.

Table 3 .
Confidence intervals values of PFT, 6MWT and IPAQ for pre-6 months, post-6 months and matched groups.
40,58,59rman's correlations with the severity of infection showed positive correlations between 6 MWT, physical activity transportation, and physical activity domestic & yard (r = 0.005, 0.01 & 0.03) respectively and positive correlation between FEF a & FEF 25-75 (r = 0.042), While the results show negative correlations between BMI, physical activity transportation and leisure & free time (r = 0.015, 0.003 & 0.012) respectively whereas presence of positive correlation between 6MWT distance & FEV 1 (r = 0.014).In addition to time factor the results show negative correlations between BMI & both physical activity of work and transportation (r = 0.015 & 0.027 and 0.001 & 0.046) in pre 6 months and post 6 months subgroup respectively.Discussion COVID-19 is a new rapidly spreading epidemic, its initial symptoms may progress to long-term consequences.Results of the current study indicate that post-COVID-19 patients may experience chest abnormalities including reductions in pulmonary function, decreases in exercise capacity, and physical activities within the average time 7.9 months after recovery time.Sights of researchers were attracted to investigate them all over the world.Our findings agree with the results of Abdallah et al, Lorent et al & Salem et al they found significant reductions in mean values of FVC, FVC% predicted, FEV 1 , PEF, PEF% predicted at the third month of recovery on comparison with matched participants.40,58,59Restrictivepattern of impairments was observed in 50% of COVID-19 patients' sample of Salem et al.40while it was 31% in the current study.A greater percent of restrictive pattern in findings of Salem et al.40may be due to their patients' sample was COVID-19 patients with pneumonia or hospitalized (more complicated), whereas the current patients' sample was selected with mild and moderate degree of infection.The current findings of pulmonary function are consistent with the findings of previous studies.Salem et al found significant reductions in pulmonary function of the survivors of COVID-19 after three months of discharge on comparison with matched controls.
40Also, Abdallah et al. found reductions in the measured FVC, total lung capacity (TLC), and DLCO at the third month in hospitalized patients with severe COVID-19.

Table 4
is not necessary.Why have to express it in Mean with SD which is not appropriate?

Response a-The figure was updated and the word drop out was removed b-the means & standard deviation in all table was replaced with median & IQR c-Table 4 as you stated it was canceled and the statements were rephrased d-the writing style of confidence interval was changed very thanks for your comments Competing Interests:
No competing interests were disclosed.
Shapiro Wilk's test -to be replaced with Kolmogorov-Smirnov test.As the sample size is >50, Shapiro-Wilk's test will not be appropriate to test the normality of data.Kolmogorov-Smirnov test would be more appropriate.
○Statistical analysis:○ Avoid using abnormal distribution.Use, not normal distribution.○ Kruskal-Wallis's test -When two groups (Group-I) and (Group-II), why was Kruskal-

: Shapiro Wilk's test -to be replaced with Kolmogorov-Smirnov test. As the sample size is >50, Shapiro-Wilk's test will not be appropriate to test the normality of data. Kolmogorov-Smirnov test would be more appropriate
Shapiro Wilk's test was replaced with Kolmogorov-Smirnov test.Wallis's test was used to compare among these three groups groups matched group, Pre-6 months group and post -6 months group as the COVID -19 group was divided into two subgroups which are pre-6 months group, post -6 months group so I used the Kruskal-Wallis's test was used to compare among three groups which are pre-6 months group, post -6 months group and matched group.After your suggestion and opinion and also consultation of statistician he agreed with your opinion the sample size of matched group, pre-6 months group and post -6 months group are different, so they only compared descriptively by using confidence intervals.andthe Kruskal-Wallis's test was canceled.The Mann Whitney test was already used to compare between COVID-group & matched non-COVID-19 group.also The sample size of the pre--6 months and post -6 months subgroups are almost similar they compared by using Mann-Whitney test.So finally the Kruskal-Wallis's test was omitted and table number 5 also was omitted.

Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Yes If applicable, is the statistical analysis and its interpretation appropriate? Yes Are all the source data underlying the results available to ensure full reproducibility? Yes Are the conclusions drawn adequately supported by the results? Yes Competing Interests:
No competing interests were disclosed.

confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. Version 1
https://doi.org/10.5256/f1000research.146511.r186229 Inclusion criteria:Please provide more details about the Non-sever COVID-19 as it is the main inclusion criteria (at least add "who diagnosed with mild-moderate COVID-19).Procedure of the study: Please provide the full details (version, model, manufacture) of the used instrument to evaluate the Pulmonary function. ○Methods:○ is better to remove or modulate the sentence of "All participants including non-infected individuals with COVID-19" since the study included non-infected healthy matched group.Author Response:Patients with COVID-19 who cannot walk, acute infections, recent surgeries.Please provide the full details (version, model, manufacture) of the used instrument to evaluate the Pulmonary function. https://spirometry.com/en/products/spirobank-ii-basic