N. Gmada

University of Carthage, Qarţājannah, Tūnis, Tunisia

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Publications (15)14.36 Total impact

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    ABSTRACT: Objective: The purpose of this study was to compare crossover and maximal fat oxidation points during cycling and running in healthy participants. Methods: Maximal oxygen uptake VO2max, maximal aerobic power (MAP) and maximal aerobic velocity (MAV) were assessed in 12 sedentary participants (aged 20.5±1.0 years), using a maximal progressive tests on a cycle ergometer and on a treadmill. Participants performed in random sequence, two submaximal graded exercise tests on a cycle ergometer (CE) and on a treadmill (TM), based on the measured MAP and MAV respectively. Respiratory parameters, the crossover (COP) and the maximal fat oxidation points (LIPOXmax) were measured during these submaximal protocols. Results: There were no significant mean (±SD) differences in COP (CE: 46.4±4.9%, TM: 47.4±3.7%; P=0.36) and in LIPOXmax (CE: 40.0±7.4%, TM: 40.2±2.1%; P=0.92) expressed in percentage of VO2max between the two modes of exercise. The metabolic indices obtained on the CE and TM were significantly correlated (COP: r=0.85; P<0.0001 and LIPOXmax: r=0.79; P<0.002). Conclusion: Our data show that COP and LIPOXmax measured during submaximal exercise (based on measured MAP or MAV) were not affected by the choice of ergometer. Both CE and TM yielded accurate and quiet similar metabolic indices that could be used to individualize training in healthy sedentary adults.
    No preview · Article · May 2015 · Science & Sports
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    ABSTRACT: Objective: was to investigate the relative and absolute reliability of cross over (COP) and maximal lipid oxidation (LIPOXmax) points during treadmill running in sedentary healthy subjects. Subjects and methods: Twelve sedentary subjects (aged 20.5±1.0years) performed in random sequence two submaximal graded exercise tests to test the criterion standard for reliability of metabolic tests on treadmill over a time interval of four days. Maximal oxygen intake and maximal aerobic velocity (MAS) were assessed, using a progressive maximal exercise test on a treadmill (Cosmed T170, Germany). Subjects performed two submaximal graded exercise tests (T1 and T2), based on the measured maximal aerobic speed (MAS). Respiratory parameters, the COP and the LIPOXmax points, and the maximal fat oxidation rate (MFO) were measured during these submaximal protocols. Results: We found no significant differences between T1 and T2 with respect to COP, LIPOXmax and the MFO. Intra-class correlation (ICC) measures of relative reliability were 0.91 for COP, 0.84 for LIPOXmax and 0.803 for MFO. Coefficients of variation (CV) for COP and MFO values between T1 and T2 were low, falling well within the 10% criterion of absolute reliability (CVCOP=9.0%, CVMFO=2.6%). However, LIPOXmax showed greater variability (CV= 15.2%). The standard error of measurement±minimal detectable change (SEM±MDC) values were 0.89±2.08mL.min-1.kg-1, 1.79±4.17mL.min-1.kg-1 and 23.74±65.80mg.min-1 for COP, LIPOXmax and MFO, respectively. The mean differences (bias)±95% limits of agreement (LOA) were 0.4±5.9mL.min-1.kg-1, -0.4±8.8mL.min-1.kg-1 and 10.3±104.05mg.min-1 for COP, LIPOXmax and MFO, respectively. Conclusion: Our data shows that COP, LIPOXmax, and MFO measurements on a treadmill, over a time interval of four days, are reproducible. These metabolic measurements could be used in sedentary subject to calibrate training intensity.
    No preview · Article · Sep 2014 · Science & Sports
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    Ouergui I · Haddad M · Padulo J · Gmada N · Bouhlel E · Behm DG
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    ABSTRACT: Taekwondo (TKD) is one of the martial arts and combat sports, which is gaining popularity around the world. In order to prescribe a specific training program, which can elucidate the metabolic demands during the competition, it is paramount to investigate the physiological responses of different forms of competitions (i.e., poomsae and combat). Moreover, it is important to know the physiological stresses associated with a variety of training forms to better orient the training program for enhanced physical performance. Thus, the objective of the present chapter is to present and explain the physiological responses of both specific forms of training and competition, and then to recommend practical applications for the prescription of TKD training programs.
    Full-text · Chapter · Jun 2014
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    ABSTRACT: The objective was to assess the reliability of the crossover point (COP) and maximal fat oxidation (LIPOXmax) points in sedentary young men.Methods Maximal oxygen intake was assessed in 12 sedentary subjects (aged 20.5 ± 1.0 years), using a progressive maximal cycle ergometer test. They performed in random sequence, two submaximal graded exercise tests (E1 and E2), based on the measured maximal aerobic power (MAP) to test the reliability. The tests were separated by 4-day interval. Blood lactate, heart rate, respiratory parameters, the COP and the LIPOXmax points were measured during these submaximal exercises.ResultsWe found no significant differences between E1 and E2 with respect to COP, LIPOXmax, and the corresponding heart rates. Coefficients of variation for COP and LIPOXmax values between E1 and E2 were low, falling well within the 10% criterion of absolute reliability. ICC measures of relative reliability were 0.96 for COP and 0.97 for LIPOXmax. The mean differences (bias) ± the 95% limits of agreement were 0.006 ± 0.066, –1.3 ± 12.15 W and 0.6 ± 7.1 W for the non-protein respiratory quotient (RER), COP and LIPOXmax, respectively. The smallest worthwhile changes for COP and LIPOXmax were 3.5 and 3.0%, respectively. The ventilatory threshold was significantly correlated to COP (r = 0.88, P < 0.001) and to LIPOXmax (r = 0.85, P < 0.001).Conclusion With appropriate care in establishing individualized submaximal protocol based on measured MAP, COP and LIPOXmax values have a good relative and absolute reliability in sedentary subjects, when they are retested over a 4-day interval. Moreover, during cycle ergometry, both of these indices are strongly correlated with the individual's ventilatory threshold.
    No preview · Article · Sep 2013 · Science & Sports
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    ABSTRACT: OBJECTIVE:: To assess the influence of Ramadan fasting on maximal performance of moderately trained young men using various tests of muscle performance. DESIGN:: Comparison of Ramadan fasting (n = 10) versus control group (n = 10) over 3 test sessions, before Ramadan (B), at the end of the first week of Ramadan (R-1), and during the fourth week of Ramadan (R-4). SETTING:: At each 2-day test session, 4 tests were performed in the same order: measurement of vertical jump height (VJH) and a force-velocity test using the arms on day 1, and measurement of handgrip force (HGF), and a force-velocity test using the legs on day 2. PARTICIPANTS:: Twenty trained men. MAIN OUTCOME MEASURES:: Maximal power of the arms and of the legs (force-velocity testing), vertical jump performance, HGF, anthropometric data, dietary intake, hemoglobin, and hematocrit. RESULTS:: Two-way analyses of variance (group × time) showed Ramadan fasters with decreased maximal anaerobic power of the arms (Wmax-A) and legs (Wmax-L) at R-1, with a partial return of arm data to initial values at R-4. VJH and HGF remained unchanged throughout. Other changes in Ramadan observers were a decreased energy intake and a decrease of plasma volume at R-1. CONCLUSIONS:: These results suggest that Ramadan observance initially had detrimental effects on Wmax-A, and Wmax-L, with a tendency to recovery by week 4 of Ramadan. Reductions of total energy intake and intramuscular glycogen may contribute to the reduced Wmax-A and Wmax-L during Ramadan fasting.
    No preview · Article · Nov 2012 · Clinical journal of sport medicine: official journal of the Canadian Academy of Sport Medicine
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    ABSTRACT: 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. 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. 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). 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.
    No preview · Article · Sep 2011 · Diabetes & Metabolism
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    ABSTRACT: The aim of this study was to examine whether measurement of peak anaerobic power (Wpeak) by force-velocity test using the arms or the legs influenced the performance obtained when the opposite muscle group was tested. Ten trained male throwers (age: 20.6 +/- 2; stature: 1.82 +/- 0.06 m; and body mass: 85.5 +/- 17.2 kg) performed, on separate days, 2 Monark cycle-ergometer protocols comprising (a) arm cranking (A1) followed by a leg cycling (L2) force-velocity test (series A-L) and (b) a leg cycling (L1) followed by an arm cranking (A2) force-velocity test (series L-A). On each day, 8 minutes of seated rest separated the 2 force-velocity tests. Arterialized capillary blood was collected from the finger tips for blood lactate analysis at rest and at the end of each force-velocity test. Wpeak-A1 and Wpeak-A2 were similar (8.1 +/- 1.7 and 8.6 +/- 1.5 W.kg, respectively). Wpeak-L1 and Wpeak-L2 were 14.0 +/- 3 and 13.4 +/- 2.8 W.kg (NS). Blood [La] increased significantly after each force-velocity test (p < 0.001), but peak blood [La] did not differ significantly between L1 (6.6 +/- 1.2) and L2 (6.2 +/- 1.4 mmol.L) or between A1 (7.2 +/- 1.0) and A2 (7.4 +/- 1.6 mmol.L). In this population, force-velocity tests performed using the legs or the arms did not induce a significant decrease in force-velocity determinations of peak anaerobic power performed subsequently with the opposite muscle group. In strength-trained athletes, the force-velocity approach can thus be used to measure the peak power output of both the legs and the arms in a single laboratory session, without adversely affecting estimates of an athlete's performance.
    Full-text · Article · Mar 2010 · The Journal of Strength and Conditioning Research
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    ABSTRACT: AimTo study the relationship between the five-jump test (5JT) performance, 30 m sprint test and vertical jump performances.
    No preview · Article · Oct 2007 · Science & Sports
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    ABSTRACT: Objective. - The study investigated physical fitness characteristics of elite Taekwondo (TKD) players as well as their heart rate (HR) response and blood lactate concentration changes during TKD specific exercises and simulated competition. Methods. - Anaerobic and aerobic power has been evaluated in eight elite TKD players (age: 20 +/- 1 years, body mass: 70.8 +/- 6 kg, Ht: 179.9 +/- 4 cm). We also measured heart rate and blood lactate concentration during competition and specific-exercises (front kicks during 10 s, 1 and 3 min). Results. - Maximum oxygen uptake (VO(2)max) and peak anaerobic power (Wpeak) averaged 56.22 +/- 2.57 ml min(-1) kg(-1) and 12.1 +/- 1.7 W kg(-1), respectively. HR and blood lactate [La] concentrations increased significantly during competition (F = 19.4, P < 0.001; F=21.3, P < 0.001) compared to the resting value. HR and [La] values were significantly correlated with those measured during 10 s (R = 0.85, P < 0.05 and R = 0.79, P < 0.05, respectively) and 3-min specific exercises (R = 0.95, P < 0.01 and R = 0.76, P < 0.05). Conclusions. - TKD requires high levels of both aerobic and anaerobic physical fitness. The correlation between specific exercises and competition is. of practical interest for TKD players and trainers. (c) 2006 Elsevier Masson SAS. All rights reserved.
    Full-text · Article · Oct 2006 · Science & Sports
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    ABSTRACT: 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.
    No preview · Article · Dec 2005 · International Journal of Sports Medicine
  • E. Bouhlel · N. Gmada · H. Debabi · Z. Tabka · Y. Feki · M. Amri
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    ABSTRACT: Objective. – Determine the kinetics of gas exchange, heart rate (HR) and blood lactate concentration [La] during and after supramaximal intermittent individualized exercises in trained (TR) and untrained (UTR) subjects.Methods.– 14 subjects (7 trained and 7 untrained subjects) performed three repetitions of an exercise corresponding to 60% of time to exhaustion at 120% of the aerobic maximum power on a cycle ergometer (MedGraphics/Excalibur, USA). The two first exercises were separated by 5 min recovery. The third exercise was followed by 20 min recovery. The oxygen uptake was measured continuously using a breath by breath device (Medgraphics/CPX). Blood was taken from fingers during recoveries for lactate analyzis.Results. – Results showed that oxygen uptake (VO2 ml/minute, P
    No preview · Article · Jun 2005 · Science & Sports

  • No preview · Article · Jan 2005 · International Journal of Sports Medicine
  • N. Gmada · E. Bouhlel · H. Debabi · Z. Tabka · Y. Feki · M. Amri
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    ABSTRACT: Objective. – Determine the influence of physical fitness level on excess post-exercise oxygen consumption after supramaximal-intermittent exercise.Method. – Fourteen subjects (seven trained and seven sedentary subjects) performed three repetitions of an exercise corresponding to 60% of time to exhaustion at 120% of the maximum aerobic power, with two recovery periods of 5 min each. The third exercise was followed by 20 min of recovery. The oxygen uptake was measured continuously using a breath-by-breath device. Blood samples were taken from fingers during recoveries for lactate analyses.Results. – The excess post-exercise oxygen consumption increased gradually during recovery in trained subjects (P
    No preview · Article · Aug 2004 · Science & Sports
  • GMADA N. · BOUHLEL E. · DEBBABI H. · TABKA Z. · FKIH Y. · AMRI M.

    No preview · Article · Jan 2004 · Science & Sports

Publication Stats

100 Citations
14.36 Total Impact Points

Institutions

  • 2015
    • University of Carthage
      • Faculty of Sciences, Bizerte
      Qarţājannah, Tūnis, Tunisia
  • 2011-2014
    • Université de Jendouba
      Souq el Arba, Jundūbah, Tunisia
  • 2007
    • Institut Supérieur du Sport et de l’Education Physique de Ksar-Said
      Tunis-Ville, Tūnis, Tunisia
  • 2004-2006
    • Institut Supérieur du Sport et de l’Education Physique
      Şafāqis, Şafāqis, Tunisia
  • 2005
    • Faculté de Médecine Ibn El Jazzar de Sousse
      Susa, Sūsah, Tunisia