Effects of combined resistance and aerobic training program on myoelectric activity of Vastus Lateralis in patients with breast cancer during adjuvant chemotherapy period.

OBJECTIVE: Chemotherapy and/or radiation are normally the predominant therapies administered to cancer patients. Commonly, patients express complaints of fatigue during adjuvant treatment. Furthermore, regular practice of physical exercise during adjuvant treatment seems to have positive effects. The aim of this study was to investigate the effects of combined muscle strength, and a supervised aerobic training program on myoelectric activity of Vastus Lateralis during isometric test in patients with breast cancer undergoing adjuvant chemotherapy. PATIENTS AND METHODS: Thirty-two women with breast cancer (20 patients in the training group and 12 patients as controls) undergoing adjuvant chemotherapy participated in the study. They took part in a 6-week training period. A muscle-strength program included isometric contraction and electrical muscle stimulation (EMS). Aerobic training program consisted of supervised intermittent cycling exercise and home-based walking exercise. The outcome measures were Root Mean Square (RMS), Mean Power Frequency (MPF), Maximal Voluntary isometric Contraction (MViC), and Endurance Time (ET) of Vastus Lateralis, before and after the training period in the two groups. RESULTS: Compared to controls, a significant increase in MViC (p=0.001) and ET (p=0.005) in quadriceps accompanied by a significant decrease in RMS (p=0.007) and a significant increase in MPF (p=0.002) has been obtained in the training group. CONCLUSIONS: Supervised muscle strength and supervised aerobic training programs enhanced muscle activity and muscular performance in women with breast cancer during adjuvant chemotherapy treatment and optimized the decrease of muscular fatigue.

First reference curves of waist circumference and waist-to-height ratio for Tunisian children.

ABDOMINAL OBESITY FOR CHILDREN: Waist circumference (WC) and waist-to-height ratio (WTHR) reference curves are used to assess the risk of cardiovascular disease in children. The aim of this study was to develop age- and sex-smoothed WC and WTHR reference curves for Tunisian children. Data were collected during the period 2014-2015 in a cross-sectional study including 2308 children aged 6-18 years. The percentiles of WC and WTHR were developed using the LMS method. The optimal percentiles, which are associated with the body mass index (BMI) according to International Obesity Task Force (IOTF) criteria to identify overweight/obesity and with the 0.5 boundary value of WTHR to estimate cardiovascular risk, were identified by ROC curves and the Youden index (j). The results show the smoothed percentiles of WC and WTHR reference curves for Tunisian children. A comparison of the 50th percentiles with other references showed different trends in WC values. The 75th percentiles of WC and WTHR are the optimal percentiles that correspond to both PBMI25 (the percentile linked to BMI≥25) and the 0.5 boundary value. However, the 90th percentiles correspond to PBMI30 (the percentile linked to BMI≥30) in boys and girls. CONCLUSION: The new WC and WTHR reference curves can be added to clinical tools to help specialists in pediatric and physical health to reduce cardiovascular risk in Tunisian children.

Body mass index reference curves for Tunisian children.

Body mass index (BMI) reference curves are used to assess children's health. The aim of this work is to construct BMI reference curves for Tunisian children and adolescents and compare them with local and international references. The BMI reference curves were constructed using the LMS method using data from 4358 Tunisian children (2182 girls and 2176 boys) aged 0-18 years. The result of this study presents the smoothed percentile curves of BMI on the basis of age and sex of Tunisian children. The reference curves of Tunisian children demonstrated some variations in comparison with the median percentiles with the references of the International Obesity Task Force (IOTF), the World Health Organization (WHO), and with local references from Algeria and Turkey. The prevalence study indicated that the rate of overweight has increased mainly in adolescent children. CONCLUSION: the new BMI reference curves could help pediatricians and fitness specialists to assess the nutritional status of Tunisian children and to reduce disease and obesity risks.

Crossover and maximal fat-oxidation points in sedentary healthy subjects: methodological issues.

AIM: Our study aimed to assess the influence of protocol on the crossover point and maximal fat-oxidation (LIPOX(max)) values in sedentary, but otherwise healthy, young men. METHODS: Maximal oxygen intake was assessed in 23 subjects, using a progressive maximal cycle ergometer test. Twelve sedentary males (aged 20.5±1.0 years) whose directly measured maximal aerobic power (MAP) values were lower than their theoretical maximal values (tMAP) were selected from this group. These individuals performed, in random sequence, three submaximal graded exercise tests, separated by three-day intervals; work rates were based on the tMAP in one test and on MAP in the remaining two. The third test was used to assess the reliability of data. Heart rate, respiratory parameters, blood lactate, the crossover point and LIPOX(max) values were measured during each of these tests. RESULTS: The crossover point and LIPOX(max) values were significantly lower when the testing protocol was based on tMAP rather than on MAP (P<0.001). Respiratory exchange ratios were significantly lower with MAP than with tMAP at 30, 40, 50 and 60% of maximal aerobic power (P<0.01). At the crossover point, lactate and 5-min postexercise oxygen consumption (EPOC(5 min)) values were significantly higher using tMAP rather than MAP (P<0.001). During the first 5 min of recovery, EPOC(5 min) and blood lactate were significantly correlated (r=0.89; P<0.001). CONCLUSION: Our data show that, to assess the crossover point and LIPOX(max) values for research purposes, the protocol must be based on the measured MAP rather than on a theoretical value. Such a determination should improve individualization of training for initially sedentary subjects.

Effect of combined active recovery from supramaximal exercise on blood lactate disappearance in trained and untrained man.

The purpose of this study was to determine the effect of different modalities of individualized active recovery on blood lactate disappearance after supramaximal exercise in subjects with different levels of aerobic fitness. Fourteen healthy subjects (7 trained and 7 untrained subjects mean age 20 +/- 1.5 and 19.5 +/- 1.5, respectively) participated in this study. They performed three supramaximal intermittent exercises at 60 % of the time to exhaustion at 120 % of the maximum aerobic power (MAP) with 5-min recovery periods (2 x 5 min). The third exercise was followed by 20 min of recovery. The effects of four types of recovery were compared in trained and untrained subjects: passive recovery (PR), an active recovery at an intensity corresponding to the first anaerobic ventilatory threshold minus 20 % (VT1), an active recovery at an intensity corresponding to the second anaerobic ventilatory threshold minus 20 % (VT2) and a combined active recovery (CR) which consisted of 7 min at VT2 followed by 13 min at VT1. Blood lactate levels were measured at rest and during the recovery periods. Peak blood lactate after supramaximal exercise was observed significantly earlier with VT2 and CR (4th min) than VT1 and PR (7th min) in trained and in untrained subjects. Combined active recovery (CR) showed a significantly faster lactate disappearance than did PR, VT1, or VT2 from the 7th min of recovery in trained subjects (p < 0.05) and at the 20th min in untrained subjects (p < 0.05). CR and VT2 conditions showed earlier peak blood lactate (4th min) than PR or VT1 (7th min). Blood lactate disappearance was faster in trained than untrained subjects during combined active recovery. This result suggests that the level of physical fitness plays an important role mainly in the pattern of blood lactate decrease during combined active recovery.