Emna Makni

Effect of individualized weight‐loss programmes on adiponectin, leptin and resistin levels in obese adolescent boys

Aim:  We investigate the effects of a 2‐month weight‐loss programme on plasma levels of adiponectin, leptin and resistin in obese adolescent boys.

Exercise improves the ApoB/ApoA-I ratio, a marker of the metabolic syndrome in obese children.

Aim:  This study was designed to examine the effect of training on components of the metabolic syndrome and ApoB/ApoA‐I ratio in obese children.

Effect of Individualized Exercise Training combined with Diet Restriction on Inflammatory Markers and IGF-1/IGFBP-3 in Obese Children

Aims: The present study was designed to examine the possible changes in body composition, insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3) and inflammatory markers of obese children in response to a 2-month program of exercise training combined with dietary restriction. Methods: Twenty-eight obese children (age 13.2 ± 0.7 years, body mass index 30.9 ± 1.3) were randomly assigned to a diet/training group or a control group and were tested two times: once before and once at the end of the experimental period. They performed a progressive cycle ergometer test at each visit. Substrate oxidation was evaluated by indirect calorimetry. Training was individualized at the point when fat oxidation was maximal (Lipoxmax). Results: Diet/training induced a significant decrease in body weight and body fat (after vs. before, p < 0.01). Plasma concentrations of IGF-1, IGFBP-3 and inflammatory markers were significantly decreased after the completion of the program. The diet/training program resulted in an increase in VO2maxACSM (24.6 ± 2.5 to 33.1 ± 3.1 ml/min/kg, p < 0.001) at the end of the intervention period. Conclu- sion: These data suggest that in the presence of weight loss, exercise training improves inflammatory markers and IGF-1 and IGFBP-3 levels in obese children.

Two-month effects of individualized exercise training with or without caloric restriction on plasma adipocytokine levels in obese female adolescents

OBJECTIVES To examine if, in young obese patients, an individualized training programme in association with a caloric restriction programme which had an effect on whole-body lipid oxidation, was able to induce changes on plasma adipocytokine concentrations. MATERIALS AND METHODS Twenty-seven obese female adolescents participated in the study. Whole-body lipid oxidation during exercise was assessed by indirect calorimetry during a graded cycle ergometer test. Body mass (BM), body mass index (BMI), percentage of body fat (%BF), insulin homeostasis model assessment (HOMA-IR) and fasting levels of circulating adipocytokines were assessed prior and after a two-month diet programme, individualized training programme targeted at Lipox(max) corresponded to the power at which the highest rate of lipids was oxidized and combined diet/training programme. RESULTS The diet/training programme induced both a shift to a higher-power intensity of Lipox(max) (+27.8 + or - 5.1 W; p<0.01) and an increase of lipid oxidation at Lipox(max) (+96.8 + or - 16.2mg/min; p<0.01). The enhancement in lipid oxidation was significantly (p<0.01) correlated with the diet/training-induced improvement in %BF (r = -0.47), HOMA-IR (r = -0.66), leptin (r = -0.41), TNF-alpha (r = -0.48), IL-6 (r = -0.38), adiponectin (r = 0.43) and resistin (r = 0.51). CONCLUSION This study showed that in obese female adolescents a moderate training protocol targeted at Lipox(max) and combined with a diet programme improved their ability to oxidize lipids during exercise, and that this improvement was associated with changes in plasma adipocytokine concentrations.

Correlation of resistin with inflammatory and cardiometabolic markers in obese adolescents with and without metabolic syndrome.

Objective: The link between plasma resistin and obesity-related cardiometabolic disorders in children remains debatable. This study assessed the relationships of plasma resistin with cardiovascular risk factors, pro-inflammatory markers and insulin resistance index (HOMA-IR) in obese (Ob) adolescents and obese adolescents with metabolic syndrome (Ob-MS) compared to healthy controls (CO). Methods: 114 obese adolescents (60 Ob, age 13.6 ± 0.9 years, BMI 28.0 ± 2.2 kg/m2, and 54 Ob-MS, age 13.8 ± 1.0 years, BMI 32.5 ± 4.8 kg/m2) and 37 CO (age 13.7 ± 0.8 years, BMI 22.8 ± 0.8 kg/m2) were studied. Anthropometrics, cardiac variables as well as fasting plasma concentrations of lipids, glucose, insulin, and adipocytokines (resistin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP)) were measured. HOMA-IR was calculated, and the presence of MS was assessed. Results: Plasma resistin was significantly higher in Ob-MS than in both Ob and CO and was correlated with anthropometric, cardiovascular, pro-inflammatory markers and several components of MS as was HOMA-IR in Ob and Ob-MS. With increasing the number of MS components, plasma resistin, pro-inflammatory markers, and HOMA-IR were also increased. Multiple regression models highlighted significant correlation between resistin and both HOMA-IR (r = 0.40, p < 0.05) and systolic blood pressure (r = 0.63, p < 0.01) in Ob-MS. Conclusion: These results support the hypothesis that there is an association between circulating resistin and childhood obesity-related inflammatory and cardiometabolic events.

Six-minute walking test and the assessment of cardiorespiratory responses during weight-loss programmes in obese children.

PURPOSE  We assessed the exercise tolerance and cardiorespiratory responses during 2-month weight-loss programmes using the 6-minute walking test (6MWT) in obese children.  METHODS  Twenty-eight male obese children were randomly assigned to either a control group (C), an energy restriction group (R), an exercise training at maximum lipid-oxidation (LIPOXmax) group (E), or an energy restriction/training group (RE). The body composition, the submaximal incremental cycling exercise, and the 6MWT were performed before and after the 2-month programme.  RESULTS . After the programme, RE group showed a significant improvement of body composition (body weight reduced by 6.3 ± 1.5 kg, p < 0.01), and an increase of 6-minute walking distance (6MWD) (+13.7%, p < 0.01). Similarly, maximum oxygen uptake calculated according to the American College of Science Medicine guideline (VO(2max) ACSM) and VO(2max) predicted from 6MWD were respectively higher (+12.9% and +10.0%, p < 0.01) than the R or E groups. Bland-Altman analysis highlighted an agreement of these two methods of VO(2max) measurement. Moreover, in all participants the 6MWD was significantly correlated with VO(2max) ACSM and LIPOXmax (r = 0.77, p < 0.001 and r = 0.67, p < 0.01; respectively) before the programme as well as their changes in percentage over the programme (r = 0.85 and r = 0.86, p < 0.0001; respectively).  CONCLUSIONS  We concluded that a 2-month weight-loss programme including energy restriction and exercise training targeted at LIPOXmax improved body composition and cardiorespiratory tolerance in obese children. Furthermore, the 6MWT could be considered as a useful and reliable tool for the assessment and the follow-up of cardiorespiratory responses during weight-loss programme in obese children.

Effect of an individualized physical training program on resting cortisol and growth hormone levels and fat oxidation during exercise in obese children

OBJECTIVES The aim of this study was to characterize the resting levels of cortisol and growth hormone (GH), and the substrate profile during exercise of obese children before and after an individualized training program. PATIENTS AND METHODS Twenty-two obese children (13.1 ± 0.8 yrs) were included in the study. Twelve individuals (six boys and six girls; 31.1 ± 1.1 kg/m², VO₂(peak)=1.92 ± 0.16l/min) participated in a two-month endurance training program and 10 individuals (five boys and five girls; 30.9 ± 1.7 kg/m², VO₂(peak)=1.98 ± 0.12l/min) served as controls. Training was individualized and targeting at the point were fat oxidation was maximal (Lipox(max)). Substrate oxidation was evaluated by indirect calorimetry. To determine plasma cortisol and GH concentrations, blood was collected at rest before and after the two-month period. RESULTS Before the program, no significant differences were detected between the training group and the control group for any of the measured anthropometric, metabolic or hormonal variables. At the end of the two-month program, training group showed an increase in VO₂(peak) and fat oxidation during exercise. After the program, resting levels of GH and cortisol were significantly increased in the training group (+0.9 ± 0.3 ng/mL and +55.4 ± 10.3 ng/mL respectively, p < 0.01). Following the two-month period, there was no change in any variables measured in control group. CONCLUSION The present data show that an individualized endurance training program targeting Lipox(max) improves fat oxidation during exercise and increases resting levels of GH and cortisol.

Multifactorial monitoring of training load in elite rugby sevens players: cortisol/cortisone ratio as a valid tool of training load monitoring.

The effectiveness of selected physiological and perceptual measures for monitoring training load and fatigue was studied in 16 male elite rugby sevens players during a 6-week intense training block (IT) and 2-week tapering (TAP). Daily training load (TL) and strain (TS) as well as weekly total score of fatigue (TSF) were quantified respectively by the session-rating of perceived exertion (RPE) method and an 8-item questionnaire. Also, testing was performed and 24 h urinary cortisol (C), cortisone (Cn), adrenaline (A) and noradrenalin (NA) excretion was measured before (T0) and after the IT (T1) and after the TAP (T2). The TL, TS and TSF increased during the IT and decreased during the TAP, in conjunction with a significant drop and improvement, respectively, of performance standards during the two periods. At T1, C and Cn levels increased while A and NA levels decreased, resulting in a higher C/Cn ratio and lower A/NA ratio, respectively. At T2, both C/Cn and A/NA returned to baseline values. The changes in C/Cn ratio, after the 6-week IT, were more closely related to mean TL, TS and TSF (r=0.75-0.76 vs. r=0.48-0.58, p<0.01) and to changes in the majority of performance measures than to A/NA ratio. Only the changes in C/Cn ratio after the 2-week TAP were related to mean TL, TS and TSF (r=0.61-0.68, p<0.01). The changes in hormone levels, training strain and performance standards reflected the physical and mental stressors of training, with complete recovery, as indicated by physiological homeostasis, achieved after an appropriate tapering period.