Original Research: Effect of sprint and strength training on glucoregulatory hormones: Effect of advanced age

International audienceThe aim of this study was to examine the effect of high-intensity sprint and strength training (HISST) on glucoregulatory hormones in young (20 years) and middle-aged (40 years) men. Thirty-six moderately trained men participated as volunteers in this study. After medical examination, eligible subjects were randomly assigned to one of four groups according to their age: a young training group (21.3 ± 1.3 yrs, YT, n = 9), a young control group (21.4 ± 1.7 yrs, YC, n = 9), a middle-aged training group (40.7 ± 1.8 yrs, AT, n = 9), and a middle-aged control group (40.5 ± 1.8 yrs, AC, n = 9). YT and AT participated in HISST for 13 weeks. Before and after HISST, all participants performed the Wingate Anaerobic Test (WAnT). Blood samples were collected at rest, after warm-up (50% VO2max), immediately post-WAnT, and 10 min post-WAnT. Before HISST, we observed significantly higher (P < 0.05) glucose concentrations in AT (5.86 ± 0.32 mmol.L(-1)) compared to YT (4.24 ± 0.79 mmol.L(-1)) at rest, and in response to WAnT (6.56 ± 0.63 mmol.L(-1) vs. 5.33 ± 0.81 mmol.L(-1)). Cortisol levels were significantly higher (P < 0.05) in AT than in YT in response to WAnT (468 ± 99.50 ng.mL(-1) vs. 382 ± 64.34 ng.mL(-1)). Catecholamine levels measured at rest and in response to WAnT rose in a similar fashion. After HISST, this "age effect" disappeared at rest and in response to exercise in the trained groups (YT and AT). Changes in hormone concentrations with intense training are due to adaptive changes in various tissues, especially in the skeletal muscle and liver in trained subjects. HISST may, at least in part, counteract the negative "age effect" on glucose metabolism

Strength Training Reduce Injury Rate In Elite Young Soccer Players During One Season

International audienceThe purpose of this study was to examine the effect of strength training on physical fitness parameters and injuries occurrence in young elite soccer players.Fifty-two elite young soccer players (13-14 yrs) were divided on a randomized order on Experimental Group (EG, n=26) and Control Group (CG, n=26). For EG, 2 to 3 sessions of strength training (90min) were introduced weekly in their training program for 12 weeks (4x3 weeks separated by 1 week recovery). Sprint tests (10-20-30m), T-test time, and jumping tests, were measured at the start (T0), at the middle (T1), and at the end of the experiment period (T2). The injury rate was recorded by the medical and fitness training staff throughout the soccer season.Compared to CG, EG performed significantly better in sprint running and T-test time at T2 (p\textless0.01). Similarly, the improvement amount for jumping tests was significantly greater (p\textless0.05) in EG compared to CG. A total of 17 injuries were recorded over the soccer season. The rate was higher in CG (13 injuries) compared to TG (4 injuries). This study showed that strength training accurately and efficiently scheduled in youth soccer players, induced performance improvement and reduced the rate of injurie

HORMONAL (CORTICAL-GONADOTROPIC AXIS) AND PHYSICAL CHANGES WITH TWO YEARS INTENSE EXERCISE TRAINING IN ELITE YOUNG SOCCER PLAYERS

International audienceHammami, MA, Ben Abderrahman, A, Hackney, AC, Kebsi, W, Owen, AL, Nebigh, A, Racil, G, Tabka, Z, and Zouhal, H. Hormonal (cortical-gonadotropic axis) and physical changes with two years intense exercise training in elite young soccer players. J Strength Cond Res 31(9): 2388-2397, 2017-The aim of this study was to investigate the effects of 2 soccer-training seasons on physical fitness and hormone concentrations in elite youth soccer players. Twenty male elite soccer players (SP, age 14.5 ± 0.4 years) and 20 male control subjects (CS, age 14.3 ± 0.3 years) participated in the study. Anthropometric measurements, aerobic (Yo-Yo Intermittent Recovery Test Level 1 [YYIRT1]) and anaerobic soccer relevant performances (jump and sprint tests), blood testosterone (T), cortisol (C), sex hormone binding globulin (SHBG), and T/C ratio were assessed 5 times (from T0 to T4) during 2 competitive seasons. Significant differences from basal values (Δ) of T, SHBG, and C between SP and CS were observed (p < 0.01). Additionally, T and T/C ratio changes were positively correlated with physical performance (p ≤ 0.05). In conclusion, as expected, higher T concentration and greater power performance were observed in the soccer players group compared with controls. Our findings also show that the T concentrations and power performance outcomes co-vary positively over the 2 soccer seasons in soccer players

Racial differences in hemoglobin and plasma volume variation implications for muscle performance and recovery

International audienceObjective - To examine the effect of race differences on sprint performance, Hemoglobin (Hb), Hematocrit (Ht) and plasma volume (PV) variation in response to repeated sprint exercise. Design - Thirty-six healthy, moderately trained men and women (20.8 ± 0.2 year-old) volunteered to participate in this study. They were allocated to one of the four groups according to their gender and race: Black men's group (BM, n = 9), White men's group (WM, n = 9), Black women's group (BW, n = 9) and White women's group (WW, n = 9). All participants performed the running-based anaerobic sprint test (RAST), which consists of six 35-m sprints with 10 s of recovery in-between. Six venous blood samples were collected to determine Hb, Ht and PV levels at rest, after warm-up, immediately post- and at 5, 15 and 30 min post-RAST. Blood lactate is also sampled during the 3rd minutes of recovery. Results - The best running time was significantly shorter (P = .002) in BW compared to WW. We have observed significantly higher Hb (P = .010) and Ht (P = .004) levels in BW compared to WW during the 5th minute of recovery. During RAST, the PV decreased significantly (P = .007) in WM only. Black groups had lower (P < .05) lactate levels compared to the white subjects. During recovery, PV increase was significantly (P = .003) higher in WW compared to BW during the 5th minute of recovery. Conclusion - This study demonstrated that sprint and repeated sprint performances were different between white and black women. Differences in anaerobic performance between the groups were associated with racial differences in lactate levels and blood count among women's group during recovery time. Hence, it is important to take into account this race-related difference in hematological parameters in responses to intense efforts