Karim Chamari

Prof. Karim Chamari

orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 May 2020 in Nutrients
Verified
Journal Article
Open access
PDF file
Achraf AmmarAchraf Ammar
Achraf Ammar
MBMichael Brach
Michael Brach
Khaled TrabelsiKhaled Trabelsi
Khaled Trabelsi
HCHamdi Chtourou
Hamdi Chtourou
Omar BoukhrisOmar Boukhris
Omar Boukhris
OCOn Behalf of the ECLB-COVID19 Consortium
On Behalf of the ECLB-COVID19 Consortium
Background: Public health recommendations and governmental measures during the COVID-19 pandemic have resulted in numerous restrictions on daily living including social distancing, isolation and home confinement. While these measures are imperative to abate the spreading of COVID-19, the impact of these restrictions on health behaviours and lifestyles at home is undefined. Therefore, an international online survey was launched in April 2020, in seven languages, to elucidate the behavioural and lifestyle consequences of COVID-19 restrictions. This report presents the results from the first thousand responders on physical activity (PA) and nutrition behaviours. Methods: Following a structured review of the literature, the “Effects of home Confinement on multiple Lifestyle Behaviours during the COVID-19 outbreak (ECLB-COVID19)” Electronic survey was designed by a steering group of multidisciplinary scientists and academics. The survey was uploaded and shared on the Google online survey platform. Thirty-five research organisations from Europe, North-Africa, Western Asia and the Americas promoted the survey in English, German, French, Arabic, Spanish, Portuguese and Slovenian languages. Questions were presented in a differential format, with questions related to responses “before” and “during” confinement conditions. Results: 1047 replies (54% women) from Asia (36%), Africa (40%), Europe (21%) and other (3%) were included in the analysis. The COVID-19 home confinement had a negative effect on all PA intensity levels (vigorous, moderate, walking and overall). Additionally, daily sitting time increased from 5 to 8 h per day. Food consumption and meal patterns (the type of food, eating out of control, snacks between meals, number of main meals) were more unhealthy during confinement, with only alcohol binge drinking decreasing significantly. Conclusion: While isolation is a necessary measure to protect public health, results indicate that it alters physical activity and eating behaviours in a health compromising direction. A more detailed analysis of survey data will allow for a segregation of these responses in different age groups, countries and other subgroups, which will help develop interventions to mitigate the negative lifestyle behaviours that have manifested during the COVID-19 confinement.

2 April 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
KKKayvan Khoramipour
Kayvan Khoramipour
KCKarim Chamari
Karim Chamari
AKAmir Hossein Ahmadi Hekmati kar
Amir Hossein Ahmadi Hekmati kar
AZAmirhosein Ziyaiyan
Amirhosein Ziyaiyan
STShima Taherkhani
Shima Taherkhani
Nicola Luigi BragazziNicola Luigi Bragazzi
Nicola Luigi Bragazzi
Adiponectin (a protein consisting of 244 amino acids and characterized by a molecular weight of 28 kDa) is a cytokine that is secreted from adipose tissues (adipokine). Available evidence suggests that adiponectin is involved in a variety of physiological functions, molecular and cellular events, including lipid metabolism, energy regulation, immune response and inflammation, and insulin sensitivity. It has a protective effect on neurons and neural stem cells. Adiponectin levels have been reported to be negatively correlated with cancer, cardiovascular disease, and diabetes, and shown to be affected (i.e., significantly increased) by proper healthy nutrition. The present review comprehensively overviews the role of adiponectin in a range of diseases, showing that it can be used as a biomarker for diagnosing these disorders as well as a target for monitoring the effectiveness of preventive and treatment interventions.

1 November 2017 in Physiology & Behavior
Verified
Journal Article
Closed access
LDLéo Djaoui
Léo Djaoui
Monoem HaddadMonoem Haddad
Monoem Haddad
KCKarim Chamari
Karim Chamari
ADAlexandre Dellal
Alexandre Dellal

Khaled TrabelsiKhaled Trabelsi
Khaled Trabelsi
Achraf AmmarAchraf Ammar
Achraf Ammar
LMLiwa Masmoudi
Liwa Masmoudi
Omar BoukhrisOmar Boukhris
Omar Boukhris
HCHamdi Chtourou
Hamdi Chtourou
OCon behalf of the ECLB-COVID19 Consortium
on behalf of the ECLB-COVID19 Consortium
Background. The COVID-19 lockdown could engender disruption to lifestyle behaviors, thus impairing mental wellbeing in the general population. This study investigated whether sociodemographic variables, changes in physical activity, and sleep quality from pre- to during lockdown were predictors of change in mental wellbeing in quarantined older adults. Methods. A 12-week international online survey was launched in 14 languages on 6 April 2020. Forty-one research institutions from Europe, Western-Asia, North-Africa, and the Americas, promoted the survey. The survey was presented in a differential format with questions related to responses “pre” and “during” the lockdown period. Participants responded to the Short Warwick–Edinburgh Mental Wellbeing Scale, the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and the short form of the International Physical Activity Questionnaire. Results. Replies from older adults (aged >55 years, n = 517), mainly from Europe (50.1%), Western-Asia (6.8%), America (30%), and North-Africa (9.3%) were analyzed. The COVID-19 lockdown led to significantly decreased mental wellbeing, sleep quality, and total physical activity energy expenditure levels (all p < 0.001). Regression analysis showed that the change in total PSQI score and total physical activity energy expenditure (F(2, 514) = 66.41 p < 0.001) were significant predictors of the decrease in mental wellbeing from pre- to during lockdown (p < 0.001, R2: 0.20). Conclusion. COVID-19 lockdown deleteriously affected physical activity and sleep patterns. Furthermore, change in the total PSQI score and total physical activity energy expenditure were significant predictors for the decrease in mental wellbeing.

23 October 2021 in Sports Medicine
Verified
Journal Article
Open access
PDF file
JWJad Adrian Washif
Jad Adrian Washif
AFAbdulaziz Farooq
Abdulaziz Farooq
Isabel KrugIsabel Krug
Isabel Krug
DPDavid Pyne
David Pyne
EVEvert Verhagen
Evert Verhagen
KCKarim Chamari
Karim Chamari
Objective: Our objective was to explore the training-related knowledge, beliefs, and practices of athletes and the influence of lockdowns in response to the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Athletes (n = 12,526, comprising 13% world class, 21% international, 36% national, 24% state, and 6% recreational) completed an online survey that was available from 17 May to 5 July 2020 and explored their training behaviors (training knowledge, beliefs/attitudes, and practices), including specific questions on their training intensity, frequency, and session duration before and during lockdown (March–June 2020). Results: Overall, 85% of athletes wanted to “maintain training,” and 79% disagreed with the statement that it is “okay to not train during lockdown,” with a greater prevalence for both in higher-level athletes. In total, 60% of athletes considered “coaching by correspondence (remote coaching)” to be sufficient (highest amongst world-class athletes). During lockdown, < 40% were able to maintain sport-specific training (e.g., long endurance [39%], interval training [35%], weightlifting [33%], plyometric exercise [30%]) at pre-lockdown levels (higher among world-class, international, and national athletes), with most (83%) training for “general fitness and health maintenance” during lockdown. Athletes trained alone (80%) and focused on bodyweight (65%) and cardiovascular (59%) exercise/training during lockdown. Compared with before lockdown, most athletes reported reduced training frequency (from between five and seven sessions per week to four or fewer), shorter training sessions (from ≥ 60 to < 60 min), and lower sport-specific intensity (~ 38% reduction), irrespective of athlete classification. Conclusions: COVID-19-related lockdowns saw marked reductions in athletic training specificity, intensity, frequency, and duration, with notable within-sample differences (by athlete classification). Higher classification athletes had the strongest desire to “maintain” training and the greatest opposition to “not training” during lockdowns. These higher classification athletes retained training specificity to a greater degree than others, probably because of preferential access to limited training resources. More higher classification athletes considered “coaching by correspondence” as sufficient than did lower classification athletes. These lockdown-mediated changes in training were not conducive to maintenance or progression of athletes’ physical capacities and were also likely detrimental to athletes’ mental health. These data can be used by policy makers, athletes, and their multidisciplinary teams to modulate their practice, with a degree of individualization, in the current and continued pandemic-related scenario. Furthermore, the data may drive training-related educational resources for athletes and their multidisciplinary teams. Such upskilling would provide athletes with evidence to inform their training modifications in response to germane situations (e.g., COVID related, injury, and illness).

27 March 2015 in Sports Medicine - Open
Verified
Journal Article
Open access
PDF file
KCKarim Chamari
Karim Chamari
Johnny PaduloJohnny Padulo
Johnny Padulo
The purpose of this Current Opinion article is to focus on the appropriate use of the terms ‘aerobic’- and ‘anaerobic’-exercise in sports medicine, in order to try to unify their use across coaches/athletes and sport scientists. Despite the high quality of most of the investigations, the terms aerobic/anaerobic continue to be used inappropriately by some researchers in exercise science. Until late 2014, for instance, 14,883 and 6,136 articles were cited in PubMed, in the field of ‘exercise science’, using the words ‘aerobic’ or ‘anaerobic’, respectively. In this regard, some authors still misuse these terms. For example, we believe it is wrong to classify an effort as ‘anaerobic lactic exercise’ when other metabolic pathways are also simultaneously involved. It has extensively been shown that the contribution of the metabolic pathways mainly depends on both exercise intensity and duration. Therefore, it is our intent to further clarify this crucial point and to simplify this terminology for coaches and sports scientists. In this regard, several research articles are discussed in relation to the terminology used to describe the predominant metabolic pathways active at different exercise durations and the oversimplification this introduces. In conclusion, we suggest that sports scientists and field practitioners should use the following terms for all-out (‘maximal’) efforts based on exercise duration: (a) ‘Explosive Efforts’ (duration up to 6 s, with preponderance of the ‘phosphagens’ metabolic pathway’); (b) ‘High Intensity Efforts’ (efforts comprised between >6 s and 1 min, with preponderance of the ‘glycolytic pathway’), and (c) ‘Endurance Intensive Efforts’ (for exercise bouts longer than 1 min, with preponderance of the ‘oxidative phosphorylation pathway’).