Effects of different training intensities in high-intensity interval training (HIIT) on maximal aerobic velocity, hematological and muscle-damage markers in healthy young adults

International audienceThis study aimed to examine the effects of two high-intensity interval training programs (HIIT) on maximal aerobic velocity (MAV), hematological variations and muscle damage markers in young healthy adults. Twenty-nine male physical education students, aged 20.3 +/- 3.3 years, volunteered to participate in this study, and were randomly assigned to a control group (CG, n = 9) or two intervention groups (group 1 or 2). Intervention group 1 (n = 10) exercised at 100% of their MAV (EG(100)) while group 2 (n = 10) exercised at 110% MAV (EG(110)). Before and after the eight week training program, blood samples were drawn at rest, before, and after an intermittent exercise. Aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), C reactive protein (CRP), creatine kinase (CK) concentrations and hematological parameters (white blood cells [WBC], monocytes [MO], lymphocytes [LY], neutrophil [NE]) and lactate dehydrogenase (LDH) were measured. Post-hoc tests showed that MAV was significantly higher in EG(110) compared to EG(100) after HIIT (p < 0.01, eta(2)(p) = 0.05), whilst ALAT, ASAT, and CPR were significantly lower (p < 0.01; 0.02 < eta(2)(p) < 0.11) in EG(110) compared to EG(100). Moreover, post-hoc tests indicated that LY decreased significantly (p < 0.001, eta(2)(p) = 0.21) only for EG(110). Furthermore, there were significant positive correlations for both EG(100) and EG(110) between MAV and ALAT (r = 0.66, p = 0.044 and r = 0.64, p = 0.041 respectively), CK (r = 0.67, p = 0.031 and r = 0.86, p = 0.030, respectively), LDH (r = 0.74, p = 0.014, and r = 0.071, p = 0.021, respectively). In addition, there was a significant positive correlation for both, EG(100) and EG(110) between MAV and LY (r = 0.79, p < 0.01; r = 0.72, p < 0.05, respectively). Concerning the relationship between MAV and NE, there was a significant positive correlation (r = 0.66; p < 0.05) only for EG(110). Findings from this study revealed that HIIT at 110% MAV was more efficient to improve MAV and reduce muscle damage. In addition, we observed significant associations between performance improvements (MAV) and markers of muscle damage

Effects of a six-week period of congested match play on plasma volume variations, hematological parameters, training workload and physical fitness in elite soccer players

[EN] Objectives The aims of this study were to investigate the effects of a six-week in-season period of soc- cer training and games (congested period) on plasma volume variations (PV), hematological parameters, and physical fitness in elite players. In addition, we analyzed relationships between training load, hematological parameters and players’ physical fitness. Methods Eighteen elite players were evaluated before (T1) and after (T2) a six-week in-season period interspersed with 10 soccer matches. At T1 and T2, players performed the Yo-Yo inter- mittent recovery test level 1 (YYIR1), the repeated shuttle sprint ability test (RSSA), the countermovement jump test (CMJ), and the squat jump test (SJ). In addition, PV and hema- tological parameters (erythrocytes [M/mm3], hematocrit [%], hemoglobin [g/dl], mean cor- puscular volume [fl], mean corpuscular hemoglobin content [pg], and mean hemoglobin concentration [%]) were assessed. Daily ratings of perceived exertion (RPE) were moni- tored in order to quantify the internal training load. Results From T1 to T2, significant performance declines were found for the YYIR1 (p<0.001, effect size [ES] = 0.5), RSSA (p<0.01, ES = 0.6) and SJ tests (p< 0.046, ES = 0.7). However, no significant changes were found for the CMJ (p = 0.86, ES = 0.1). Post-exercise, RSSA blood lactate (p<0.012, ES = 0.2) and PV (p<0.01, ES = 0.7) increased significantly from T1 to T2. A significant decrease was found from T1 to T2 for the erythrocyte value (p<0.002, ES = 0.5) and the hemoglobin concentration (p<0.018, ES = 0.8). The hematocrit percentage rate was also significantly lower (p<0.001, ES = 0.6) at T2. The mean corpuscular volume, mean corpuscular hemoglobin content and the mean hemoglobin content values were not statisti- cally different from T1 to T2. No significant relationships were detected between training load parameters and percentage changes of hematological parameters. However, a signifi- cant relationship was observed between training load and changes in RSSA performance (r = -0.60; p<0.003). Conclusions An intensive period of “congested match play” over 6 weeks significantly compromised play- ers’ physical fitness. These changes were not related to hematological parameters, even though significant alterations were detected for selected measures

Physiological adaptations in response to short and chronic intermittent exercise

L’optimisation de la performance en endurance oblige l’athlète à répéter des séances d’entraînement intermittent à haute intensité (EIHI), ce qui génère une fatigue neuromusculaire qui peut être préjudiciable. Ce type d’EIHI peut être aussi à l’origine des perturbations importantes de l’homéostasie générale affectant ainsi le volume plasmatique et les réponses physiologiques. Ainsi, l’objectif de ce travail de thèse est d’étudier l’effet de l’intensité d’EIHI (100% vs. 110% de VMA) sur les performances en endurances, marqueurs des dommages musculaires, le volume plasmatique et les réponses inflammatoires suite à l’exercice intermittent. Pour les études 2, 3 et 4, quatre groupes de sujets masculins et sains ont participé à ce travail. Ils ont été répartis d’une façon aléatoire en 2 groupes expérimentaux (GE100 et GE110) et en 2 groupes contrôles (GC100 et GC110). Pour l’étude 1, seulement 3 groupes (GE100, GE110 et GC) ont participé à l’expérimentation. En effet, deux programmes d’EIHI ont été mis à disposition avec un EI à 100% de VMA (pour GE100) et un EI à 110% de VMA (pour GE110). Les résultats montrent que l’EIHI s’accompagne d’une augmentation significative du volume plasmatique chez les deux groupes entrainés. Ces changements du volume plasmatique ont été accompagnés par une augmentation des performances physiques mesurée lors de l’exercice maximal à charge croissante et lors de l’exercice intermittent chez les groupes entrainés. Nos résultats ont révélé un taux d’amélioration plus élevé en suivant un EIHI à 110% de VMA. Des adaptations endocriniennes sont probablement à l’origine de ces modifications liées à l’entrainement intense. En effet, après entrainement, nous avons observé une diminution significative des marqueurs des dommages musculaires (au repos et à l’exercice intermittent) chez les sujets entrainés par rapport aux groupes contrôles. La différence liée à l’intensité de l’EIHI disparait après entrainement seulement entre les groupes entrainés. Le même constat a été observé concernant les concentrations plasmatiques des cytokines. En conclusion de ce travail de thèse, il semble que l’augmentation de l’intensité d’EIHI serait un bon moyen pour réduire et atténuer les effets délétères de l'EI supra-maximal. Le majeur fruit de ce travail est que l'intensité de 110% de VMA provoque une meilleur amélioration des performances aérobies que 100% de VMA, tout en avoir le même niveau de variation plasmatique, voir même des préférences au niveau des réponses inflammatoires.Optimization of endurance performance requires the athlete to repeat high intensity interval training (HIIT). This type of training can induce a neuromuscular fatigue, a homeostasis perturbation which affects the plasma volume and the physiological responses. Thus, the aim of this study is to examine the effect of increasing HIIT intensity (100% vs. 110% of VMA) on endurance performance, muscular damage marker, plasma volume and inflammatory responses after an intermittent exercise (IE). For the first study, only 3 groups (EG100, EG110 and CG) participated in the experiment. However, in the2 sd, 3rd and 4th studies, 39 male volunteered to participate in this study. They were randomly assigned in control groups (CG100 and CG110), trained group with 100% of maximal aerobic velocity (MAV) (EG100) and trained group with 110% MAV (EG110). The training program consisted of 3 sessions a week during 8 weeks and presented only 30/30s IE. Before and after HIIT, participants performed a maximal graded test (MGT) and IE test at 100% or 110% MAV with 30s recovery at 50% MAV. Blood was collected at rest, at the end of the IE and after 15min of passive recovery. Results showed that increasing IT running intensity by 10% of MAV increases significantly the PVV at rest and after the IET. Despite the fact that EG100 and EG110 had the same PVV rise level after HIIT, greater aerobic performances were recorded in EG110. Our results revealed a higher improvement in response to HIIT at by following a 110% VAM EIHI. Endocrine adaptations are probably the cause of these changes related to intense training. Indeed, after training, we observed a significant decrease in markers of muscle damage (resting and intermittent exercise) in subjects trained compared to control groups. The difference related to the intensity of the EIHI disappears after training only between the groups trained. The same observation has been observed concerning the plasma concentrations of cytokines. In conclusion of this thesis work, it seems that increasing the intensity of EIHI would be a good way to reduce and mitigate the deleterious effects of the supra-maximal EI. In conclusion, HIIT at 110% MAV provoked better aerobic performances than 100% MAV, while having the same plasma volume and inflammatory responses levels

Effect of three fitness programs on strength, speed, flexibility and muscle power on sedentary subjects

International audienceBACKGROUND: The aim of this study was to research and compare the effect of Crossfit® (CF), LesMills® (LM) and traditional resistance (TRAD) training program on short performances. METHODS: Participants were assigned randomly into 3 groups and followed the training sessions allocated at the rate of 5 sessions/week for 16 weeks. A battery of tests including anthropometric and performance measures were carried out over three sessions: before training (T0), after eight weeks (T1) and sixteen weeks of training (T2). RESULTS: Findings indicated that strength tests demonstrated a significant time effect (p&lt;0.001, ηp 2=0.6), the results showed that CF and TRAD groups improved strength every 8 weeks while LM group only at T2, The speed test demonstrated also a significant time effect (p&lt;0.001 , ηp 2=0.5) the results showed an improvement in speed every 8 weeks for LM, at T2 for CF and no change for TRAD, for flexibility, all tests demonstrated a main time effect (p&lt;0.001 , ηp 2=0.46 - 0.7) CF was the best in shoulder range of motion and LM in trunk and lower limb flexibility, all power tests also demonstrated a significant time effect (p&lt;0.001 , ηp 2=0.76 - 0.9) the improvement for all groups was every 8 weeks. CONCLUSIONS: Based on these findings, we recommend TRAD and CF as valuable trainings for strength development, LM for flexibility and all three trainings for power improvement

First growth reference curves for Tunisian children and adolescents

International audienceA growth chart is a powerful graphical tool displaying children’s growth patterns. The aim of this study was to develop growth reference curves appropriate for Tunisian children. The collection of data from this cross-sectional study was conducted on 4358 healthy subjects (2182 girls and 2176 boys) in three pediatric centers and 15 schools. Smoothed growth curves were estimated using the LMS method. The smoothed percentile curves for height, weight, sitting height (SH), and leg length (LL) increase rapidly during the 1st years of life and then progress slowly until 18 years. However, the sitting height-to-height ratio (SHTHR) curves decrease sharply before the age of 4 and then stabilize in both sexes. In addition, the comparison between boys and girls indicated that the values are very similar at most ages. Except during puberty, the values in boys increase (P&lt;0.0001) for the weight, height, SH, and LL parameters and decline (P&lt;0.0001) in the SHTHR compared to the values in girls. The growth rate curves presented two remarkable velocity peaks: the first appears during the 1st years of life and the second at puberty. Height gains at the last stage of growth (puberty) are around 15.45% of final height for boys and 15.52% for girls. This study showed a number of discrepancies for certain age groups when comparing the median weight and height values with those of the World Health Organization, the National Center for Health Statistics, and Algerian references in both sexes. Conclusion: The smoothed percentile curves for weight and height will be useful to access the general growth of Tunisian children. Furthermore, the SH, LL, and SHTHR curves can be used to monitor body proportions during childhood

Effect of training at intensities around critical velocity on 400 meters front crawl performance in young swimmers

International audienceBACKGROUND: Young swimmers are rarely involved in training control, leading to inadequate volume and prescription of training intensities. This study aimed to examine the effect of prescribing and monitoring training intensities around critical velocity (CV) on 400 m frontcrawl performance during an 8-weeks period. METHODS: Twenty young male swimmers (13.4±1.0 years) were randomly assigned into two groups. The experimental group (EG) used training monitoring based on intensities around CV (95, 100, 105 and 110% of CV), while for the control group (CG) different heart-rate (HR) zones (EN1+, EN2, EN2+ and EN3) were used as an intensity criterion. The training volume was the same for both EG and CG. A maximal 400 m front-crawl test was performed before and after the 8-week period to determine CV intensities and to assess alternations in performance. The rate of perceived exertion (RPE) and HR values were also evaluated. RESULTS: Significant main effects of time were observed for T400, CV, HR and RPE. A significant group x time interaction was found for T400 (p=0.035, effect size=1.07, moderate). Results revealed significant pre-to-post improvements for both EG (from 328.46±26.25 to 305.88±20.09) and CG (from 329.07±25.24 to 314.75±19.87). A significant group x time interaction was also found for CV (p=0.005, effect size=1.51, large). Results revealed significant pre-to-post improvements for both EG (from 1.126±0.08 to 1.207±0.07) and CG (from 1.124±0.08 to 1.173±0.07). CONCLUSIONS: Both training methods induced significant improvements in 400 m front-crawl performance with a greater degree for the training prescription and monitoring using CV intensities

Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise

International audiencePurpose:We studied the effect of two interval training programs of varying intensities (100% vs. 110% of maximal aerobic velocity [MAV]) on hematocrit (Ht), hemoglobin (Hb), and plasma volume variations (PVV) in young men.Methods: Thirty-nine male volunteered were assigned to two control groups (CG100, n = 9 and CG110, n = 10), and two training groups (one with 100% MAV [EG100, n = 10] and one with 110% MAV [EG110, n = 10]). All participants performed a maximal graded exercise test and an intermittent exercise (IE) protocol. Blood was collected at rest, at the end of the IE and after 15 min of recovery, before and after 8-weeks-training. Interval training (IT) sessions consist of 30s IE run at 100% or 110% MAV with 30s recovery at 50% MAV.Results: After training, time to exhaustion (TTE) was improved in EG110 (+613.7) and EG100 (+397.5). This improvement was greater in EG110 than EG100 (p < 0.005). After training, Hb deceased in EG100 and EG110 at rest (p < 0.01), at the end of IE (p = 0.000) and after 15 min of recovery (p = 0.01). This decrease was more slightly more substantial at rest in EG100 (−0.6%) than EG110 (−0.3%). After training, Ht decreased in EG100 and EG110 at rest (p = 0.001), at the end of IE (p = 0.000) and at 15 min of recovery (p = 0.01). This decrease was more important in EG110 than EG100 at rest (−2.7%), at the end of IE (−2.1%) and after 15 min recovery. After training, PVVrest and PVVend increased in EG100 (+2.2%) and EG110 (+3.2%). No significant difference between EG100 and EG110 was observed.Conclusion:Increasing IT intensity by 10% MAV increases PVVrest and PVVend. Despite the fact that EG100 and EG110 had the same PVVend after training, greater performances were recorded in EG110

Effects of Recovery Mode during High Intensity Interval Training on Glucoregulatory Hormones and Glucose Metabolism in Response to Maximal Exercise

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Combined sprint and resistance training abrogates age differences in somatotropic hormones.

The aim of this investigation was to compare serum growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) in response to a combined sprint and resistance training (CSRT) program in young and middle-aged men.Thirty-eight healthy, moderately trained men participated in this study. Young and middle-aged men were randomly assigned to, a young training group (YT = 10, 21.4±1.2yrs) ora young control group (YC = 9, 21.6±1.8 yrs), a middle-aged training group (MAT = 10, 40.4±2.1 yrs) or a middle-aged control group (MAC = 9, 40.5±1.8 yrs). Participants performed the Wingate Anaerobic Test (WAnT) before and after a 13-week CSRT program (three sessions per week). Blood samples were collected at rest, after warm-up, immediately post-WAnT, and 10 min post-WAnT. CSRT induced increases in GH at rest and in response to the WAnT in YT and MAT (P0.05). In response to the WAnT, amelioration of the age-effect was observed between YT and MAT for IGF-1 and IGF-1/IGFBP-3 ratio following CSRT (P>0.05). These data suggest that CSRT increases the activity of the GH/IGF-1 axis at rest and in response to the WAnT in young and middle-aged men. In addition, CSRT reduces the normal age-related decline of somatotropic hormones in middle-age men

Plasma Volume Variations in Professional Soccer Players: Difference Between Pre- and Competitive Season

International audienceBackground: Variations in plasma volume and hematological parameters occur before and after training in soccer players. However, there are no reports on changes in hematological parameters resulting from a half-season of training in professional soccer players. Objectives: To investigate the effects of training load on plasma volume variations in elite soccer players. Methods: Twenty soccer players from the 1st French division soccer league (Ligue 1) were included in the study. The training load was evaluated using the rating of perceived exertion (RPE, 10- Borg scale) after each training session and each match. Anthropometrics characteristics, hematocrit (Ht), hemoglobin (Hb) and plasma volume variations (PVV) were assessed at 3 different times: T1: Baseline (before the first week of pre-season), T2: At the end of pre-season (after 8 weeks of training) and T3: At the end of the first competitive period (after 26 weeks of training and at halfway of the competitive season). Results: Values of Ht and lean body mass (LBM) increased during the first competitive period from T1 to T3 (Ht: ∆↑8%, P = 0.037, effect sizes (ES) = 1.0; LBM: ∆↑4%, P = 0.041, ES = 0.83) and from T2 to T3 (LBM: (∆↑2%; P = 0.05; ES = 0.77). Moreover, PVV decreased from T2 to T3 (P = 0.002, ES = 0.5) and from T1 to T3 (P &amp;amp;lt; 0.05; ES = 1.26). There were no differences in Hb at T1, T2 or T3. Conclusions: Changes in body weights, PVV and Ht during preparatory and competitive phases were affected by the training load and competitive play