HIGH-INTENSITY DISTANCE IN ELITE FEMALE SOCCER PLAYERS BASED ON A GENDER-SPECIFIC THRESHOLD

Introduction The total distance covered in elite matches by female soccer players is relatively lower than their male counterparts (Bradley et al. 2014). The majority of female match play is spent in low-intensity activities with high-intensity distance been 30% lower than male players (Andersson et al. 2010). To date, studies on female players utilized the same absolute velocity threshold of male players despite female player having a lower physical capacity than male players (Bradley and Vescovi, 2015). The aim of this study was to examine high-intensity distance covered during matches by elite female soccer players using different thresholds. Methods Nineteen elite female players participated in this study (age 23\ub14 yr; height 165\ub17 cm; body mass 54.7\ub16.5 kg). Maximal oxygen consumption (VO2max) and respiratory compensation threshold (VT2) were determined by graded exercise test to exhaustion on a motorized treadmill. Players activities across 6 friendly matches (32 observations) were tracked by Global Positioning System (K-Gps 10hz, K-Sport, Italy). Distance covered in total (TD) and at high-intensity (HID) were evaluated. The latter was calculated using both the typical male speed threshold of 15 km\ub7h-1 (MALE) and an individual speed threshold (IND) corresponding to VT2 (Hunter et al. 2015). Results Players VO2max was 49.1\ub13.7 mL\ub7kg-1\ub7min-1 and occurred at a speed value of 14.7\ub10.8 km\ub7h-1. VT2 corresponded to a running speed of 13.5\ub10.9 km\ub7h-1. The total distance covered was 7726\ub1891 m with HID higher (p<0.0001) in IND (1125\ub1533 m) than in MALE (785\ub1353 m). When expressed as percentages of TD, HID was 14.4\ub15.8% in IND and 9.9\ub13.8% in MALE. Discussions These data demonstrate in female soccer that the quantification of high-intensity running activities during match play can be impacted by applying relative or absolute speed thresholds. Even if arbitrary speed thresholds enable longitudinal monitoring of match-demands and comparison within and between players/teams/gender, the utilization of individualized speed threshold should be pursue in order to quantify the correct exercise stimulus in female soccer players. Further studies are needed to understand the best method characterizing the multiple transitions between intensity-domains in female soccer. References Andersson HA, Randers MB, Heiner-Moller A, Krustrup P, Mohr M. (2010). J Strength Cond Res. 24, 912-919. Bradley PS and Vescovi JD. (2015). Int J Sport Phys & Perf. 10, 112-116. Bradley PS, Dellal A, Mohr M, Castellano J, Wilkie A. (2014). Hum Mov Sci. 33, 159-71. Hunter F, Bray J, Towlson C, Smith M, Barrett B, Madden B, Abt G, Lovell R. (2015). Int J Sport Phys & Perf. 36, 41-48. Contact [email protected]

Match running performance and physical capacity profiles of U8 and U10 soccer players

Aim This study aimed to characterize match running performance of very young soccer players and evaluate the relationship between these data and physical capacities and technical skills. Methods Distances covered at different speed thresholds were measured during 31 official matches using GPS technology in U10 (n = 12; age 10.1 ± 0.1 years) and U8 (n = 15; age 7.9 ± 0.1 years) national soccer players. Counter movement jump performance (CMJ), 20 m shuttle running (20 m-SR), linear sprint performance (10, 20, 30 m), shuttle (SHDT) and slalom dribble tests (SLDT) were performed to determine the players physical capacities and technical skills. Results Physical capacities and technical skills were higher in U10 versus U8 players [P 0.05, ES: 0.74). The U10 players covered more total (TD) and high-intensity running distance (HIRD) than their younger counterparts did (P 0.05, ES: 0.99). TD and HIRD covered across the three 15 min periods of match play did not decline (P > 0.05, ES: 0.02–0.55). Very large magnitude correlations were observed between the U8 and U10 players performances during the 20 m-SR versus TD (r = 0.79; P < 0.01) and HIRD (r = 0.82; P < 0.01) covered during match play. Conclusions Data demonstrate differences in match running performance and physical capacity between U8 and U10 players, and large magnitude relationships between match play measures and physical test performances. These findings could be useful to sports science staff working within the academies

Remodeling of cholinergic input to the hippocampus after noise exposure and tinnitus induction in Guinea pigs

Here, we investigate remodeling of hippocampal cholinergic inputs after noise exposure and determine the relevance of these changes to tinnitus. To assess the effects of noise exposure on the hippocampus, guinea pigs were exposed to unilateral noise for 2 hr and 2 weeks later, immunohistochemistry was performed on hippocampal sections to examine vesicular acetylcholine transporter (VAChT) expression. To evaluate whether the changes in VAChT were relevant to tinnitus, another group of animals was exposed to the same noise band twice to induce tinnitus, which was assessed using gap‐prepulse Inhibition of the acoustic startle (GPIAS) 12 weeks after the first noise exposure, followed by immunohistochemistry. Acoustic Brainstem Response (ABR) thresholds were elevated immediately after noise exposure for all experimental animals but returned to baseline levels several days after noise exposure. ABR wave I amplitude‐intensity functions did not show any changes after 2 or 12 weeks of recovery compared to baseline levels. In animals assessed 2‐weeks following noise‐exposure, hippocampal VAChT puncta density decreased on both sides of the brain by 20–60% in exposed animals. By 12 weeks following the initial noise exposure, changes in VAChT puncta density largely recovered to baseline levels in exposed animals that did not develop tinnitus, but remained diminished in animals that developed tinnitus. These tinnitus‐specific changes were particularly prominent in hippocampal synapse‐rich layers of the dentate gyrus and areas CA3 and CA1, and VAChT density in these regions negatively correlated with tinnitus severity. The robust changes in VAChT labeling in the hippocampus 2 weeks after noise exposure suggest involvement of this circuitry in auditory processing. After chronic tinnitus induction, tinnitus‐specific changes occurred in synapse‐rich layers of the hippocampus, suggesting that synaptic processing in the hippocampus may play an important role in the pathophysiology of tinnitus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150542/1/hipo23058.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150542/2/hipo23058_am.pd

Il Core training : tra evidenze scientifiche e applicazioni pratiche

Da alcuni anni il termine core training \ue8 entrato a far parte del lessico di molti allenatori e terapisti. \uc8 credenza diffusa che questa metodologia di allenamento possa contribuire a migliorare le prestazioni in molti sport e ridurre l\u2019incidenza di infortuni. Nonostante la sua popolarit\ue0, per\uf2, la letteratura scientifica non \ue8 in grado di offrire conclusioni definitive circa la reale efficacia di tale mezzo di allenamento. Lo scopo di questo articolo \ue8 di analizzare i risultati della ricerca scientifica e di fornire indicazioni utili agli allenatori per programmare e scegliere le esercitazioni pi\uf9 adeguate agli obiettivi dell\u2019allenament

The effects of PHV on physical performance on young soccer players

Introduction. In youth soccer academy categories are organized into annual age groups in order to provide similar competition level and age specific training program (Deprez et al, 2012). Several studies (Figueiredo et al, 2009) have shown better performance in strength, power, speed and endurance in relation to a faster biological maturity in the same age group. Talent identification is often based on physical capacities and so there is the risk that players who are physically less mature may be deselected but not on the basis of their adult potential. No studies evaluated a possible correlation between age of peak height velocity (APHV) and physical capacities. The aim of this study was to examine the relationship between APHV and physical capacities in young soccer players. Methods. 158 young soccer players (8-16 years old) were recruited in this study. Players had their APHV indirectly estimated by the leg length, height and weight using equation from Mirwald et al (2002): Maturity off set = \u20139.236 + 0.0002708 7 (leg length 7 sitting height) \u2013 0.001663 7 (decimal age 7 leg length) + 0.007216 7 (decimal age 7 sitting height) + 0.02292 7 (weight/height ratio). Counter movement jump (CMJ), agility (Illinois test modified for young players), linear sprint performance (5, 10, 20 m), balance (Y balance test, YBT) and flexibility (Sit and reach test, S&R) were evaluated to determine the players\u2019 physical capacities. Relationships between APHV and physical variables were evaluated using Pearson\u2019s product-moment correlation. The magnitudes of the correlations were considered as trivial (0.9) and perfect (1.0) in accordance with Hopkins et al (2009). Statistical significance was set at P<0.05. Results. All physical variables were significantly correlated with APHV. Very large magnitude correlations were observed between APHV and linear sprint performance on 5, 10 and 20 meters (P<0.001, r=-0.71; P<0.001, r=-0.82; P<0.001, r=-0.86, respectively), large magnitude correlations were observed between APHV and agility test (P<0.001, r=-0.56), S&R (P<0.001, r=0.55) and CMJ (P<0.001, r=0.52), moderate magnitude correlation was found between APHV and YBT (P<0.001, r=0.38). Conclusions. Our results indicated correlations between APHV and physical performance in young soccer players and so the physical capacities should be evaluates in relation to individual biological maturation for talent identification and in order to program appropriate training in groups with a great variability of APHV. References. Deprez D, Vaeyens R, Coutts AJ, Lenoir M, Philippaerts R. Int J Sports Med, 2012;33(12):987-93. Figueiredo A J, Gon\ue7alves C E, Coelho e Silva M J, Malina R M. Ann Hum Biol, 2009;36:60-73. Mirwald R L, Baxter-Jones AD G, Bailey D A, Beunen G P. Med Sci Sport Exerc, 2002;34:689-694 Hopkins WG, Marshall SW, Batterham AM, Hanin J. Med Sci Sports Exerc, 2009;41:3-13