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1.
Biol Sport ; 39(2): 307-317, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35309525

RESUMEN

The aim of the present study was to analyse the influence of congested periods of matches on the acceleration (Acc) and deceleration (Dec) profiles of elite soccer players. Twenty-three elite male professional soccer players participated in the study across 31 official matches. Assessed periods included: (i) congested periods (three to four days between games), and (ii) non-congested periods (more than four days between games). Physical activity during matches was recorded during games using a 10Hz global positioning system device, coupled with a 100 Hz accelerometer, and was analysed according to the periods. Maximal Acc- (73.2 ± 20.3 vs. 84.918.5 m), high Acc- (244.0 ± 49.5 vs. 267.0 ± 37.8 m), maximal Dec- (139.0 ± 44.8 vs. 152.039.3 m) and the total decelerating- distance (5132 ± 690 vs. 5245 ± 552 m) were lower in congested than in non-congested periods (p < 0.05, effect size 0.31-0.70). Neither a main effect of playing position nor a period*playing position interaction on Acc and Dec were observed (p > 0.05). It was concluded that Acc and Dec match activities were significantly affected during congested periods compared to non-congested highlighting a possible fatigue accumulation being responsible for the observed decrement in physical activity. Monitoring Acc and Dec metrics throughout particular periods of congested fixtures amongst professional soccer teams is advised and may be a way to assess physical and fatigue status.

2.
J Strength Cond Res ; 32(5): 1342-1351, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-28557851

RESUMEN

Malone, S, Mendes, B, Hughes, B, Roe, M, Devenney, S, Collins, K, and Owen, A. Decrements in neuromuscular performance and increases in creatine kinase impact training outputs in elite soccer players. J Strength Cond Res 32(5): 1342-1351, 2018-The aim of the current investigation was to understand the impact of pretraining neuromuscular performance and creatine kinase (CK) status on subsequent training performance in elite soccer players. Thirty soccer players (age: 25.3 ± 3.1 years; height: 183 ± 7 cm; mass: 72 ± 7 kg) were involved in this observational study. Each morning before training, players completed assessments for neuromuscular performance (countermovement jump; CMJ) and CK levels. Global positioning technology provided external load: total distance, high-speed distance, sprint distance, accelerations, decelerations, average metabolic power, explosive distance, and high metabolic power distance (>25.5 W·kg). Mixed-effect linear models revealed significant effects for CK and CMJ Z-score on total high-speed distance, very high-speed distance, accelerations, decelerations, explosive distance, and maximal velocity. Effects are reported with 90% confidence limits. A CK Z-score of +1 corresponded to a -5.5 ± 1.1, -3.9 ± 0.5, -4.3 ± 2.9%, -4.1 ± 2.9%, -3.1 ± 2.9%, and -4.6 ± 1.9%, reduction in total high-speed distance, very high-speed distance, accelerations, decelerations, explosive distance, and maximal velocity, respectively. Countermovement jump Z-score of -1 corresponded to a -3.5 ± 1.1, -2.9 ± 0.5, -2.1 ± 1.4, -5.3 ± 2.9%, -3.8 ± 2.9%, -1.1 ± 2.9%, and -5.6 ± 1.2% reduction in these external load measures. Magnitude-based analysis revealed that the practical size of the effect of a pretraining CMJ Z-score of -1 and CK Z-score of +1 would have on total high-speed distance, very high-speed distance, high metabolic power distance (>25.5 W·kg), accelerations, decelerations, explosive distance, and maximal velocity was likely negative. The results of this study suggest that systematic pretraining monitoring of neuromuscular and muscle stress within soccer cohorts can provide coaches with information about the training output that can be expected from individual players during a training session.


Asunto(s)
Rendimiento Atlético/fisiología , Creatina Quinasa/sangre , Carrera/fisiología , Fútbol/fisiología , Aceleración , Adulto , Desaceleración , Humanos , Modelos Lineales , Masculino , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Estudios Prospectivos , Adulto Joven
4.
Res Sports Med ; 26(4): 462-473, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29969288

RESUMEN

The study aimed to assess the changes in the perceived internal load and wellness status of volleyball players in preparatory, regular (i.e. uncongested), and congested weeks during a full season. Thirteen elite volleyball players were studied (237 training sessions and 37 official matches). Session-RPE, muscle soreness, stress, fatigue, sleep quality, and the Hooper Index were measured daily using questionnaires. Training sessions were classified based on the number of matches per week and the days before or after a match: preparatory (no match), regular (one match), and congested weeks (two or more matches). Pairwise comparisons found significantly greater session-RPE scores (p < 0.05) one day before the match (304.74 A.U.), in regular weeks than in congested weeks (204.40 A.U.). Matches during the congested weeks (364.71 A.U.) had significantly higher session-RPE scores (p < 0.05) than regular weeks (252.97 A.U.). Three days before the match involved significantly higher values of muscle soreness, fatigue, stress, and sleep quality than regular weeks. Match accumulation increased the session-RPE training load of the matches. This study provides insights into the training load and well-being status before competition, for training the day of competition, and after the competition.


Asunto(s)
Estado de Salud , Acondicionamiento Físico Humano , Voleibol , Carga de Trabajo , Adulto , Atletas , Fatiga , Humanos , Estudios Longitudinales , Masculino , Mialgia , Sueño
5.
Psychol Sci ; 28(1): 47-55, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27837182

RESUMEN

A recent study has linked individual differences in face recognition to rs237887, a single-nucleotide polymorphism (SNP) of the oxytocin receptor gene ( OXTR; Skuse et al., 2014). In that study, participants were assessed using the Warrington Recognition Memory Test for Faces, but performance on Warrington's test has been shown not to rely purely on face recognition processes. We administered the widely used Cambridge Face Memory Test-a purer test of face recognition-to 370 participants. Performance was not significantly associated with rs237887, with 16 other SNPs of OXTR that we genotyped, or with a further 75 imputed SNPs. We also administered three other tests of face processing (the Mooney Face Test, the Glasgow Face Matching Test, and the Composite Face Test), but performance was never significantly associated with rs237887 or with any of the other genotyped or imputed SNPs, after corrections for multiple testing. In addition, we found no associations between OXTR and Autism-Spectrum Quotient scores.


Asunto(s)
Cara , Memoria/fisiología , Oxitocina/genética , Receptores de Oxitocina/genética , Reconocimiento en Psicología/fisiología , Adolescente , Adulto , Trastorno del Espectro Autista , Femenino , Genotipo , Humanos , Masculino , Oxitocina/fisiología , Polimorfismo de Nucleótido Simple , Conducta Social , Adulto Joven
6.
J Strength Cond Res ; 31(6): 1509-1517, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28538299

RESUMEN

The aim of the present study was to compare (a) the maximal sprinting speed (MSS) attained by soccer players during matches (MSSmatch) according to their level of play (professional first French division vs. elite amateur fourth French division) and the playing positions and (b) the MSS attained by professional soccer players during 14 different types of small-sided games (SSG, MSSSSG) and match-play. All players monitored through the study performed a 40-m sprint test to assess individual MSS (MSStest) and compare it to the training and match activity, with the calculation of the percentage of MSStest (%MSStest) reached. No differences were found according to the level of play; however, positional wide players achieved a higher MSSmatch, %MSStest, and MSSSSG than central players (both defenders and midfielders) during matches and SSG. MSSmatch were higher than all MSSSSG, and MSSSSG were positively correlated with the area of the pitch (0.45, p < 0.001), its length (0.53, p < 0.001), and the number of players involved (0.38, p < 0.001). The closer SSG was to match situation in terms of rules, the higher the MSSSSG. Wide players reached higher MSS in match and SSG than central players, confirming the relevance of using SSG close to match situation to specifically prepare elite players to the maximal running speed demand of the match.


Asunto(s)
Atletas , Carrera/estadística & datos numéricos , Fútbol/estadística & datos numéricos , Adulto , Rendimiento Atlético , Francia , Sistemas de Información Geográfica , Humanos , Masculino , Acondicionamiento Físico Humano , Adulto Joven
7.
J Strength Cond Res ; 31(9): 2388-2397, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27676275

RESUMEN

Hammami, 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.


Asunto(s)
Rendimiento Atlético/fisiología , Hidrocortisona/biosíntesis , Globulina de Unión a Hormona Sexual/biosíntesis , Fútbol/fisiología , Testosterona/biosíntesis , Adolescente , Pesos y Medidas Corporales , Ejercicio Físico/fisiología , Frecuencia Cardíaca , Humanos , Masculino , Aptitud Física/fisiología , Estaciones del Año
8.
J Sports Sci ; 34(6): 542-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26710880

RESUMEN

Young soccer players often use one particular dominant leg (DL) to perform dynamic movements which require strength, resulting in leg asymmetry. The aim of this study was to compare, in young soccer players, the effect of using DL and non-dominant leg (NDL) on time performance of two change of direction (COD) manoeuvres in several angles of COD. Seventy-three young male soccer players (mean ± SD, age: 16.1 ± 1.8 year) participated in this study. Players performed 10-m sprints, either in a straight line or with a COD (5 m straight ahead and a turn of 45°, 90°, 135° and 180° to the opposite side of the DL or NDL). Testing for COD speed was conducted over two different manoeuvres: (1) sidestepping and (2) bypass. Maximal isometric voluntary contraction of the knee extensors/flexors and hip abductors/adductors was also measured using a handheld dynamometer. For sidestepping, COD performance with use of the DL was significantly better compared to the NDL (P < 0.05) in all angles of COD. However, bypass COD performance through use of the DL was better compared to the NDL only when turning at 135°. Additionally, strength of the knee extensors/flexors and hip abductors of the DL was significantly (P < 0.05) greater than the NDL. The use of the DL allows better COD performance than the NDL when sidestepping manoeuvre is used. However, the DL allows better COD performance than the NDL only at 135° with the use of the bypass manoeuvre. Furthermore, the greater strength of the DL compared to the NDL may contribute to COD performance difference between legs.


Asunto(s)
Lateralidad Funcional/fisiología , Pierna/fisiología , Destreza Motora/fisiología , Fútbol/fisiología , Adolescente , Fenómenos Biomecánicos , Cadera/fisiología , Humanos , Contracción Isométrica , Rodilla/fisiología , Masculino , Fuerza Muscular/fisiología , Estudios de Tiempo y Movimiento
9.
J Strength Cond Res ; 30(9): 2460-9, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24448005

RESUMEN

Owen, AL, Wong, DP, Dunlop, G, Groussard, C, Kebsi, W, Dellal, A, Morgans, R, and Zouhal, H. High-intensity training and salivary immunoglobulin A responses in professional top-level soccer players: Effect of training intensity. J Strength Cond Res 30(9): 2460-2469, 2016-This study aimed (a) to test the hypothesis that salivary immunoglobulin A (s-IgA) would vary with training intensity sessions (low-intensity [LI] vs. high-intensity sessions [HI]) during a traditional training program divided into 4 training periods and (b) to identify key variables (e.g., GPS data, rating of perceived exertion [RPE], and training duration), which could affect s-IgA. Saliva samples of 10 elite professional soccer players were collected (a) before the investigation started to establish the baseline level and (b) before and after each 4 training sessions (LI vs. HI). Training intensity was monitored as internal (through heart rate responses and RPE) and external (through GPS) loads. High-intensity sessions were associated with higher external load (GPS) and with higher RPE. Baseline and pretraining s-IgA did not differ between the 4 training sessions both for HI and LI. Post-training s-IgA were not different (in absolute value and in percentage of change) between HI and LI sessions at the first 3 periods. However, at the fourth period, s-IgA concentration for HI session was significantly lower (p ≤ 0.05) than the LI session. The percentage change between s-IgA post-training and s-IgA baseline concentrations differ significantly (p ≤ 0.05) between HI and LI training sessions. Significant correlations between s-IgA and training intensity were also noted. High-intensity soccer training sessions might cause a significant decrease in s-IgA values during the postexercise window as compared with LI sessions. This study encourages coaches to monitor s-IgA in routine, particularly during HI training periods, to take precautions to avoid upper respiratory tract infection in highly trained soccer players.


Asunto(s)
Entrenamiento de Intervalos de Alta Intensidad , Inmunoglobulina A Secretora/metabolismo , Saliva/metabolismo , Fútbol/fisiología , Adulto , Humanos , Masculino , Esfuerzo Físico
10.
Res Sports Med ; 24(4): 375-386, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27574867

RESUMEN

Perceived changes due to training monotony, strain, sleep, stress, fatigue, muscle soreness and the influence of specific training sessions on the affective valence were explored in professional soccer players. Seventeen players completed the Hooper questionnaire, the ratings of perceived exertion and feeling scale (FS) every training/match day before and during the soccer season. Higher players' training loads were recorded during pre-season when compared with in-season period (2558.1 ± 262.4 vs. 1642.8 ± 169.3 a.u., p < 0.01; respectively). The ratings of sleep, stress, fatigue and muscle soreness in pre-season were higher than those observed during in-season (p < 0.01) whereas the feeling score was lower (p < 0.01). Furthermore, training sessions, including technical/tactical work, induced an improved feeling score but linked with a lower training load when compared with sessions focus on physical emphasis (p < 0.01). Pre-season period of training induces a significantly more strenuous and exhausting demands on professional soccer players compared with the in-season period at the elite level.


Asunto(s)
Conducta Competitiva/fisiología , Estado de Salud , Salud Mental , Acondicionamiento Físico Humano/efectos adversos , Fútbol/fisiología , Fútbol/psicología , Adulto , Fatiga/diagnóstico , Fatiga/etiología , Fatiga/psicología , Indicadores de Salud , Humanos , Masculino , Mialgia/diagnóstico , Mialgia/etiología , Mialgia/psicología , Acondicionamiento Físico Humano/fisiología , Acondicionamiento Físico Humano/psicología , Estaciones del Año , Sueño/fisiología , Estrés Fisiológico , Estrés Psicológico/diagnóstico , Estrés Psicológico/etiología
11.
J Sports Sci ; 33(20): 2100-5, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26158195

RESUMEN

In professional soccer, the benefits of lower limb strength training have been advocated. However, from an aspect of performance development, specifically with respect to expression of fatigue and injury prevention, the advantages of increased lower body strength have received limited attention at the elite level of the game. The primary aim of this cross-sectional investigation was to examine the association between lower body strength and the expression of markers of fatigue as evaluated through muscle damage assessment following match play in professional soccer players. Ten male professional soccer players participated in this investigation (mean ± SD age 26.2 ± 4.3 years, height 181.6 ± 4.8 cm and body mass 78.7 ± 6.1 kg); creatine kinase (CK) was collected 2-days post-match for a 5-month period and at three different time points (Phase 1, Phase 2 and Phase 3); muscular strength (e.g. 4 repetition half-squat) was measured 3-day post-match. No significant change in CK and muscular force across three time points was found (F = 0.60, P = 0.56, η(2) = 0.06 and F = 2.65, P = 0.10, η(2) = 0.23, respectively). Muscular force was negatively correlated (moderate to very large) with CK. It can be concluded that players who produce greater lower body force as a result of being stronger in the lower limbs show reduced levels of CK 48 h post-match.


Asunto(s)
Extremidad Inferior/fisiología , Fuerza Muscular/fisiología , Músculo Esquelético/lesiones , Fútbol/lesiones , Fútbol/fisiología , Adolescente , Adulto , Rendimiento Atlético/fisiología , Biomarcadores/metabolismo , Creatina/metabolismo , Estudios Transversales , Humanos , Masculino , Fatiga Muscular/fisiología , Músculo Esquelético/enzimología , Entrenamiento de Fuerza , Adulto Joven
12.
J Strength Cond Res ; 29(6): 1705-12, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26010801

RESUMEN

Elite-level professional soccer players are suggested to have increased physical, technical, tactical, and psychological capabilities when compared with their subelite counterparts. Ensuring these players remain at the elite level generally involves training many different bodily systems to a high intensity or level within a short duration. This study aimed to examine whether an increase in training volume at high-intensity levels was related to injury incidence, or increased the odds of sustaining an injury. Training intensity was monitored through time spent in high-intensity (T-HI) and very high-intensity (T-VHI) zones of 85-<90% and ≥90% of maximal heart rate (HRmax), and all injuries were recorded over 2 consecutive seasons. Twenty-three, elite professional male soccer players (mean ± SD age, 25.6 ± 4.6 years; stature, 181.8 ± 6.8 cm; and body mass, 79.3 ± 8.1 kg) were studied throughout the 2-years span of the investigation. The results showed a mean total injury incidence of 18.8 (95% confidence interval [CI], 14.7-22.9) injuries per 1,000 hours of exposure. Significant correlations were found between training volume at T-HI and injury incidence (r = 0.57, p = 0.005). Further analysis revealed how players achieving more time in the T-VHI zone during training increased the odds of sustaining a match injury (odds ratio = 1.87; 95% CI, 1.12-3.12, p = 0.02) but did not increase the odds of sustaining a training injury. Reducing the number of competitive match injuries among elite-level professional players may be possible if greater focus is placed on the training intensity and volume over a period of time ensuring the potential reduction of fatigue or overuse injuries. In addition, it is important to understand the optimal training load at which adaptation occurs without raising the risk of injury.


Asunto(s)
Frecuencia Cardíaca , Sistema Musculoesquelético/lesiones , Acondicionamiento Físico Humano/métodos , Acondicionamiento Físico Humano/fisiología , Fútbol/lesiones , Adulto , Traumatismos en Atletas/epidemiología , Traumatismos en Atletas/prevención & control , Trastornos de Traumas Acumulados/prevención & control , Humanos , Incidencia , Masculino , Acondicionamiento Físico Humano/efectos adversos , Factores de Tiempo , Adulto Joven
13.
J Opt Soc Am A Opt Image Sci Vis ; 31(4): A47-54, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24695201

RESUMEN

Distinct neural populations carry signals from short-wave (S) cones. We used individual differences to test whether two types of pathways, those that receive excitatory input (S+) and those that receive inhibitory input (S-), contribute independently to psychophysical performance. We also conducted a genome-wide association study (GWAS) to look for genetic correlates of the individual differences. Our psychophysical test was based on the Cambridge Color Test, but detection thresholds were measured separately for S-cone spatial increments and decrements. Our participants were 1060 healthy adults aged 16-40. Test-retest reliabilities for thresholds were good (ρ=0.64 for S-cone increments, 0.67 for decrements and 0.73 for the average of the two). "Regression scores," isolating variability unique to incremental or decremental sensitivity, were also reliable (ρ=0.53 for increments and ρ=0.51 for decrements). The correlation between incremental and decremental thresholds was ρ=0.65. No genetic markers reached genome-wide significance (p<5×10(-7)). We identified 18 "suggestive" loci (p<10(-5)). The significant test-retest reliabilities show stable individual differences in S-cone sensitivity in a normal adult population. Though a portion of the variance in sensitivity is shared between incremental and decremental sensitivity, over 26% of the variance is stable across individuals, but unique to increments or decrements, suggesting distinct neural substrates. Some of the variability in sensitivity is likely to be genetic. We note that four of the suggestive associations found in the GWAS are with genes that are involved in glucose metabolism or have been associated with diabetes.


Asunto(s)
Percepción de Color/genética , Percepción de Color/fisiología , Células Fotorreceptoras Retinianas Conos/citología , Adolescente , Adulto , Sensibilidad de Contraste/genética , Sensibilidad de Contraste/fisiología , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Estimulación Luminosa , Psicofísica , Adulto Joven
14.
Invest Ophthalmol Vis Sci ; 65(8): 24, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-39012638

RESUMEN

Purpose: Within the healthy population there is a large variation in the ability to perform smooth pursuit eye movements. Our purpose was to investigate the genetic and physiological bases for this variation. Methods: We carried out a whole-genome association study, recording smooth pursuit movements for 1040 healthy volunteers by infrared oculography. The primary phenotypic measure was root mean square error (RMSE) of eye position relative to target position. Secondary measures were pursuit gain, frequency of catch-up saccades, and frequency of anticipatory saccades. Ten percent of participants, chosen randomly, were tested twice, giving estimates of test-retest reliability. Results: No significant association was found with three genes previously identified as candidate genes for variation in smooth pursuit: DRD3, COMT, NRG1. A strong association (P = 3.55 × 10-11) was found between RMSE and chromosomal region 1q42.2. The most strongly associated marker (rs701232) lies in an intron of KCNK1, which encodes a two-pore-domain potassium ion channel TWIK-1 (or K2P1) that affects cell excitability. Each additional copy of the A allele decreased RMSE by 0.29 standard deviation. When a psychophysical test of visually perceived motion was used as a covariate in the regression analysis, the association with rs701232 did not weaken (P = 5.38 × 10-12). Conclusions: Variation in the sequence or the expression of the pH-dependent ion channel TWIK-1 is a likely source of variance in smooth pursuit. The variance associated with TWIK-1 appears not to arise from sensory mechanisms, because the use of a perceptual covariate left the association intact.


Asunto(s)
Estudio de Asociación del Genoma Completo , Canales de Potasio de Dominio Poro en Tándem , Seguimiento Ocular Uniforme , Humanos , Seguimiento Ocular Uniforme/fisiología , Masculino , Femenino , Adulto , Canales de Potasio de Dominio Poro en Tándem/genética , Adulto Joven , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Concentración de Iones de Hidrógeno , Voluntarios Sanos , Genotipo , Movimientos Sacádicos/fisiología
15.
Hum Genet ; 132(4): 415-21, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23263445

RESUMEN

Men and women differ statistically in the relative lengths of their index and ring fingers; and the ratio of these lengths has been used as a biomarker for prenatal testosterone. The ratio has been correlated with a wide range of traits and conditions including prostate cancer, obesity, autism, ADHD, and sexual orientation. In a genome-wide association study of 979 healthy adults, we find that digit ratio is strongly associated with variation upstream of SMOC1 (rs4902759: P = 1.41 × 10(-8)) and a meta-analysis of this and an independent study shows a probability of P = 1.5 × 10(-11). The protein encoded by SMOC1 has recently been shown to play a critical role in limb development; its expression in prostate tissue is dependent on sex hormones, and it has been implicated in the sexually dimorphic development of the gonads. We put forward the hypothesis that SMOC1 provides a link between prenatal hormone exposure and digit ratio.


Asunto(s)
Estudio de Asociación del Genoma Completo , Hormonas Esteroides Gonadales/genética , Osteonectina/genética , Adulto , Femenino , Regulación de la Expresión Génica/genética , Hormonas Esteroides Gonadales/metabolismo , Humanos , Masculino , Osteonectina/biosíntesis , Próstata/metabolismo
16.
J Strength Cond Res ; 27(12): 3275-85, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23524368

RESUMEN

Due to the continual physical, physiological, and psychological demands of elite level soccer increasing the incidence and risk of injuries, preventative training programs have become a common feature of soccer players training schedule. The aim of the current investigation was to examine the effectiveness of a structured injury prevention program on the number of muscle injuries and the total number of injuries within elite professional soccer. The present study was conducted over 2 consecutive seasons, of which the first (2008-2009) being the intervention season and the second the control season (2009-2010). In total, 26 and 23 elite male professional soccer players competing within the Scottish Premier League and European competition participated. The training program was performed twice weekly for the entirety of the season (58 prevention sessions). The results revealed an increase in the total number of injuries within the intervention season (88 vs. 72); however, this was largely due to the greater number of contusion injuries sustained within the intervention season (n = 44) when compared with control season (n = 23). Significantly less muscle injuries were observed during the intervention season (moderate effect), and this occurred concomitant with a bigger squad size (large effect, p < 0.001). The findings from this study identify that a multicomponent injury prevention-training program may be appropriate for reducing the number of muscle injuries during a season but may not be adequate to reduce all other injuries.


Asunto(s)
Traumatismos en Atletas/prevención & control , Músculo Esquelético/lesiones , Entrenamiento de Fuerza/métodos , Fútbol/lesiones , Adulto , Humanos , Masculino , Fuerza Muscular , Equilibrio Postural , Fútbol/fisiología
17.
J Strength Cond Res ; 27(5): 1400-6, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-22820208

RESUMEN

The aim of this study was to examine the physical performance of a successful Italian Serie A team of more than 3 consecutive seasons. Twenty-five players participated in the study and were classified into 3 playing positions: defenders (n = 9), midfielders (n = 11), and forwards (n = 5). Activities match were studied by an analysis of multiple match camera SICS throughout the competition Italian Serie A matches played at home (n = 90) for 3 consecutive seasons (first: 2004/2005; second: 2005/2006; and third: 2006/2007). Total team ball possession and time-motion characteristics were examined. Results showed that total ball possession (52.1-54.9%) and the number of points accumulated at home (40/48) improved in the past 3 seasons, whereas the final rankings at home were stable. The total distances covered by minutes of play were significantly different between the 3 seasons (118.32 ± 6.69 m·min to 111.96 ± 8.05 m·min). Distance running and high-intensity activities were similar in the 3 seasons, whereas the distance covered in moderate-intensity running decreased in the third (p < 0.05). Variations between playing positions were found during the 3 consecutive seasons, with midfielders covering greater distances than defenders (p < 0.05) and forwards (p < 0.01). This study showed how for 3 consecutive seasons a Serie A team of successful players reduced their distances performed at submaximal speeds, and increased ball possession, while maintaining the high-intensity activities and the number of points at home. It is suggested that this is because of a better understanding of roles and tactics team organization and to act collectively and individually on these parameters to reduce energy expenditure during the game to maintain a high-level performance throughout the season.


Asunto(s)
Rendimiento Atlético/fisiología , Conducta Cooperativa , Fatiga/prevención & control , Procesos de Grupo , Fútbol/fisiología , Adulto , Metabolismo Energético , Humanos , Italia , Masculino , Estudios Retrospectivos , Estudios de Tiempo y Movimiento
18.
Br J Ophthalmol ; 107(11): 1730-1735, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35273018

RESUMEN

BACKGROUND: Physiological anisocoria is an asymmetry of pupil size in the absence of pathology. METHODS: Images of the pupils under standard illumination were collected in the course of a whole-genome association study of a range of visual functions in 1060 healthy adults. DNA for each participant was extracted from saliva samples. RESULTS: We found no relationship between anisocoria and the difference in refraction between the eyes, nor between anisocoria and difference in acuity. There was a small but significant relationship with lightness of the iris, in that the eye with the smaller pupil was associated with the lighter iris. There was a strong association between anisocoria and a local region of chromosome 13 (13q32.1), a region lying between the genes GPR180 and SOX21. The strongest association was with the single-nucleotide polymorphism rs9524583. CONCLUSION: The very specific region associated with anisocoria is one where microdeletions (or microduplications) are known to lead to abnormal development of pupil dilator muscle and hence to the autosomal dominant condition of microcoria. It is possible that alterations at 13q32.1 act by altering the expression of SOX21, which encodes a nuclear transcription factor.

19.
Proc Biol Sci ; 279(1745): 4263-71, 2012 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-22896642

RESUMEN

The sensory abnormalities associated with disorders such as dyslexia, autism and schizophrenia have often been attributed to a generalized deficit in the visual magnocellular-dorsal stream and its auditory homologue. To probe magnocellular function, various psychophysical tasks are often employed that require the processing of rapidly changing stimuli. But is performance on these several tasks supported by a common substrate? To answer this question, we tested a cohort of 1060 individuals on four 'magnocellular tasks': detection of low-spatial-frequency gratings reversing in contrast at a high temporal frequency (so-called frequency-doubled gratings); detection of pulsed low-spatial-frequency gratings on a steady luminance pedestal; detection of coherent motion; and auditory discrimination of temporal order. Although all tasks showed test-retest reliability, only one pair shared more than 4 per cent of variance. Correlations within the set of 'magnocellular tasks' were similar to the correlations between those tasks and a 'non-magnocellular task', and there was little consistency between 'magnocellular deficit' groups comprising individuals with the lowest sensitivity for each task. Our results suggest that different 'magnocellular tasks' reflect different sources of variance, and thus are not general measures of 'magnocellular function'.


Asunto(s)
Vías Visuales/fisiología , Estudios de Cohortes , Femenino , Humanos , Masculino , Percepción de Movimiento , Estimulación Luminosa , Percepción Visual
20.
J Strength Cond Res ; 26(10): 2712-20, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22130398

RESUMEN

The purpose of this study was to compare the effects of small-sided games (SSGs) in soccer versus high-intensity intermittent training (HIT) on a continuous aerobic test (Vameval) and the performance in an intermittent test with changes of direction (CODs; 30-15 intermittent fitness test [30-15(IFT)]). Twenty-two amateur soccer players (mean age ± SD: 26.3 ± 4.7 years) were assigned to 3 different groups for 6 weeks: SSG group (n = 8), HIT group (n = 8), and control group (CG; n = 6). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 9 sessions of 2 versus 2 and 1 versus 1 SSGs, whereas the HIT group performed 9 sessions of intermittent runs in the form of 30 seconds of effort interspersed with 30 seconds of passive recovery (30s-30s), 15s-15s, and 10s-10s. The HIT and SSG groups showed performance improvements in the Vameval test (5.1 and 6.6%, respectively) and the 30-15(IFT) intermittent test with CODs (5.1 and 5.8%, respectively), whereas there was no change in the performance of the CG. Players from HIT and SSG groups showed similar increase in their performance in the 30-15(IFT) and the Vameval tests during the 6-week training period, especially with an increase significantly different to that in a traditional training as in the CG (p < 0.05). This investigation demonstrates that both SSG and HIT interventions are equally effective in developing the aerobic capacity and the ability to perform intermittent exercises with CODs in male amateur soccer players. Furthermore, these 2 methods of training applied during the 6 weeks induce similar effect on the recovery capacity and on the ability to repeat directional changes of 180°. Coaches will now be able to choose between these two methods according to the objective of the training and to optimize the training.


Asunto(s)
Rendimiento Atlético/fisiología , Resistencia Física/fisiología , Fútbol/fisiología , Adulto , Atletas , Prueba de Esfuerzo/métodos , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Carrera/fisiología , Adulto Joven
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