Range of Motion and Injury Occurrence in Elite Spanish Soccer Academies. Not Only a Hamstring Shortening-Related Problem.

Sanz, A, Pablos, C, Ballester, R, Sanchez-Alarcos, JV, and Huertas, F. Range of motion and injury occurrence in elite Spanish soccer academies. Not only a hamstring shortening-related problem. J Strength Cond Res 34(7): 1924-1932, 2020-Age-related development of range of motion (ROM) during an active hip flexion (active straight leg raise) and its relationship with hamstring injury occurrence were examined in 1657 young male soccer players (9-18 years of age). Age-related differences in ROM showed a significant decrease from U9 to U11 (p = 0.001), from U11 to U13 (p < 0.005), and from U9 to U13 (p < 0.001), whereas ROM increased from U13 to U15 and from U13 to U18 (both p's < 0.001). Interestingly, younger and older players reached similar ROM values (U9-U18, p = 0.87). Higher ROM was found in dominant than nondominant leg in all age groups (all ps < 0.001). No differences related to playing position were found on ROM (all ps > 0.478). During the follow-up period (11 months) 97 hamstring injuries were reported showing higher rates in the older age groups (p < 0.001) and outfield players (p < 0.001). Remarkably, no differences in ROM average were found between injured players and noninjured players (p = 0.152). Our results suggest that ROM during hip flexion does not only depend on the hamstrings shortening but also on the variables related to joint stability, motor control, and hip flexor muscle weakness. Sport scientists in youth sport soccer academies should develop age-specific screening and action plans to develop strength, motor control, and flexibility to optimize ROM and reduce injuries from the grassroots stages.

Muscle Activation in the Main Muscle Groups of the Lower Limbs in High-Level Dancesport Athletes.

Dancers are subjected to high-intensity workouts when they practice dancesport, and according to the literature, they are prone to injury, primarily of the lower limbs. The purpose of this study was to determine whether differences exist in relative activation amplitudes for dancers involved in dancesport due to muscle, gender, and type of dance. Measurements were carried out using surface electromyography equipment during the choreography of a performance in the following leg muscles: rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius medialis. Eight couples of active dancesport athletes (aged 20.50±2.75 yrs) were analyzed. Significant gender differences were found in rumba in the tibialis anterior (p≤0.05) and gastrocnemius medialis (p≤0.05). Based on the different activations, it is possible to establish possible mechanisms of injury, as well as tools for preventing injuries and improving sports performance.

The difficulty of postural tasks amplifies the effects of fatigue on postural stability.

PURPOSE: It was supposed that the difficulty of postural tasks accentuates the effects of fatigue on postural stability. The aim of this work was to compare the effects of fatiguing running on three different postural conditions presenting different levels of difficulty: a standing still position with the eyes open (EO condition), a standing still position with the eyes closed (EC condition) and a shooting position with the eyes open (SP condition). The SP condition required a rifle to be held horizontally with the arms and a standing posture with the non-dominant foot ahead of the dominant foot. METHODS: Thirty-two male soldiers 32.2 ± 3.8 years old completed a maximal incremental protocol on a treadmill by running until they reached a state of fatigue. The three postural conditions were evaluated in a randomized order before and after the fatiguing exercise with the use of a force platform which recorded the displacements of the centre of foot pressure. RESULTS: Following the fatiguing running exercise, postural stability was affected to a greater extent in the SP condition than in the EO condition and the EC condition. CONCLUSION: The requirements of the SP condition modify the entire postural organization and this challenges balance control to a greater extent than when in EO and EC standing still positions, following fatiguing exercise. The difficulty of postural tasks thus amplifies the effects of fatigue on postural stability.

Certification of protein biomarker standards using element MS and generic standards: Application to human cytokines.

The availability of protein standards and methods for their characterization, quantification, and purity assessment are currently a bottleneck in absolute quantitative proteomics. In this work, we introduce an absolute quantitative analytical strategy based on ICP-MS sulfur detection that uses sulfate as generic standard to quantify and certify the mass purity of protein standards. The methodology combines capillary chromatographic separation with parallel detection with ICP-MS and ESI-MS to determine proteoforms concentration and identity, respectively. The workability of the methodology was demonstrated using recombinant human cytokine standards IP-10 and Flt3L (2 batches), which are relevant biomarkers for carcinoma or inflammatory diseases. Every key factor (transport efficiency, column recovery, signal stability and internal standard suitability) was taken into account and certified BSA standard was used as quality control for validation purposes. Protein quantification values and resulting mass purity certification of IP-10 and one batch of Flt3L were very high (100 and 86%, respectively). Lower mass purity obtained for another batch of Flt3L (<70%) concurred with the finding of significant proteoforms resulted from oxidation processes as observed by parallel ESI-MS.

The progression of paraspinal muscle recruitment intensity in localized and global strength training exercises is not based on instability alone.

OBJECTIVE: To evaluate electromyographic activity of several paraspinal muscles during localized stabilizing exercises and multijoint or global stabilizing exercises. DESIGN: Cross-sectional counterbalanced repeated measures. SETTING: Research laboratory. PARTICIPANTS: Volunteers (N=25) without low-back pain. INTERVENTION: Subjects performed (1) localized stabilizing exercises (callisthenic exercises with only body weight as resistance): static lumbar extension, stable (on floor) and unstable static unipedal forward flexion, stable dynamic unipedal forward flexion, and unstable supine bridge; and (2) global stabilizing exercises (70% of maximum voluntary isometric contraction [MVIC]): dead lift and lunge. MAIN OUTCOME MEASURES: Mean and maximum amplitude of the electromyographic RMS of the lumbar and thoracic multifidus spinae and erector spinae. Electromyographic signals were normalized to the MVIC achieved during a back-extension exercise. RESULTS: Normalizing to the MVIC, paraspinal muscles were significantly (P<.05) most active, with mean and peak amplitudes of 88.1% and 113.4% during the dynamic stable dead lift at 70% of MVIC, respectively. The supine bridge on the unstable surface obtained the significantly lowest values of 29.03% and 30.3%, respectively. The other exercises showed intermediate values that ranged from 35.4% to 61.6%. CONCLUSION: Findings from this study may be helpful to strength trainers and physical therapists in their choice of exercises for strengthening paraspinal muscles. Our results suggest that in asymptomatic young experienced subjects, the dead lift at 70% of MVIC provides higher levels of mean and peak electromyographic signals than localized stabilizing exercises and other types of global stabilizing exercises.

DHA- Rich Fish Oil Improves Complex Reaction Time in Female Elite Soccer Players.

Omega-3 fatty acids (n-3) has shown to improve neuromotor function. This study examined the effects of docosahexaenoic acid (DHA) on complex reaction time, precision and efficiency, in female elite soccer players. 24 players from two Spanish female soccer Super League teams were randomly selected and assigned to two experimental groups, then administered, in a double-blind manner, 3.5 g·day(-1) of either DHA-rich fish oil (FO =12) or olive oil (OO = 12) over 4 weeks of training. Two measurements (pre- and post-treatment) of complex reaction time and precision were taken. Participants had to press different buttons and pedals with left and right hands and feet, or stop responding, according to visual and auditory stimuli. Multivariate analysis of variance displayed an interaction between supplement administration (pre/post) and experimental group (FO/OO) on complex reaction time (FO pre = 0.713 ± 0.142 ms, FO post = 0.623 ± 0.109 ms, OO pre = 0.682 ± 1.132 ms, OO post = 0.715 ± 0.159 ms; p = 0.004) and efficiency (FO pre = 40.88 ± 17.41, FO post = 57.12 ± 11.05, OO pre = 49.52 ± 14.63, OO post = 49. 50 ± 11.01; p = 0.003). It was concluded that after 4 weeks of supplementation with FO, there was a significant improvement in the neuromotor function of female elite soccer players. Key pointsThe results obtained from the study suggest that supplementation with DHA produced perceptual-motor benefits in female elite athletes.DHA could be a beneficial supplement in sports where decision making and reaction time efficiency are of importance.

Deadlift muscle force and activation under stable and unstable conditions.

The objective of this study was to compare the production of force and paraspinal muscle activity between deadlifts carried out in a standard way and with different instability devices (Bosu and T-Bow). Deadlifts involve the performance of muscle activities with dynamic and isometric characteristics. Thirty-one subjects participated voluntarily in the study. Initially, they performed an isometric test for 5 seconds in each condition. After that, they performed a set of 5 repetitions with 70% of the maximum isometric force obtained in each one of the previously evaluated conditions. During the isometric tests, records of electromyographic activity and force production were obtained, whereas during the dynamic tests, only the electromyographic activity was registered. The subjects produced more force and muscle activity on the stable surface than under the other conditions during the isometric test (p < 0.05), and the same differences in muscle activity were observed during the dynamic test (p < 0.05). These data show that the performance of deadlifts under stable conditions favors a higher production of maximum strength and muscle activity. Therefore, we conclude that the use of instability devices in deadlift training does not increase performance, nor does it provide greater activation of the paraspinal muscles, leading us to question their value in the performance of other types of exercises.

Influence of a Combined Gluten-Free and Casein-Free Diet on Behavior Disorders in Children and Adolescents Diagnosed with Autism Spectrum Disorder: A 12-Month Follow-Up Clinical Trial.

The use of alternative interventions, such as gluten-free and casein-free (GFCF) diets, is frequent due to limited therapies for Autism Spectrum Disorder (ASD). Our aims were to determine the influence of a GFCF diet on behavior disorders in children and adolescents diagnosed with ASD and the potential association with urinary beta-casomorphin concentrations. Thirty-seven patients were recruited for this crossover trial. Each patient consumed a normal diet (including gluten and casein) for 6 months and a GFCF diet for another 6 months. The order of the intervention (beginning with normal diet or with GFCF diet) was assigned randomly. Patients were evaluated at three time-points (at the beginning of the study, after normal diet and after GFCF diet). Questionnaires regarding behavior and autism and dietary adherence were completed and urinary beta-casomorphin concentrations were determined at each time-point. No significant behavioral changes and no association with urinary beta-casomorphin concentrations were found after GFCF diet. A 6-month GFCF diet do not induce significant changes in behavioral symptoms of autism and urinary beta-casomorphin concentrations. Further studies with a long follow-up period similar to ours and including placebo and blinding elements are needed to identify better those respondents to GFCF diets.

Relation of body mass index and body fat mass for Spanish university students, taking into account leisure-time physical activity.

The objective of this cross-sectional study was to analyze the relation of Body Mass Index with body fat mass while taking into account the amount of leisure-time physical activity for 299 male university students. Body fat mass was measured by bioelectrical impedance analysis. An estimation of energy expenditure in leisure-time physical activity in metabolic equivalents (METs) was obtained so participants were divided into six activity groups by percentile: no physical activity by the first group and participants physically active were divided into five groups by percentiles: < 25%, 26-50%, 51-75%, 76-90%, and 91-100%. Correlations of Body Mass Index with body fat mass were strong in different groups-values ranged from .76 to .85, except for the > 90% group.

A lower-limb training program to improve balance in healthy elderly women using the T-bow device.

Ageing impairs balance, which increases the risk of falls. Fall-related injuries are a serious health problem associated with dependency and disability in the elderly and results in high costs to public health systems. This study aims to determine the effects of a training program to develop balance using a new device called the T-Bow. A total of 28 women > 65 years were randomly assigned to an experimental group (EG) (n = 18; 69.50 [0.99] years), or a control group (CG) (n = 10; 70.70 [2.18] years). A program for lower limbs was applied for 8 weeks using 5 exercises on the T-Bow: squat, lateral and frontal swings, lunges, and plantarflexions. The intensity of the exercises was controlled by time of exposure, support base, and ratings of perceived exertion. Clinical tests were used to evaluate variables of balance. Static balance was measured by a 1-leg balance test (unipedal stance test), dynamic balance was measured by the 8-foot-up-and-go test, and overall balance was measured using the Tinetti test. Results for the EG showed an increase of 35.2% in static balance (P < 0.005), 12.7% in dynamic balance (P < 0.005), and 5.9% in overall balance (P > 0.05). Results for the CG showed a decline of 5.79% in static balance (P > 0.05) but no change in the other balance variables. Thus the data suggest that implementing a training program using the T-Bow could improve balance in healthy older women.

Determinants of leisure-time physical activity and future intention to practice in Spanish college students.

Few studies analyze determinants and patterns of physical activity among college students, so it has not been possible to carry out effective interventions to promote this practice. The aim of this study was to analyze the associations between some personal, social, and environmental determinants, practice of physical activity and future intention to practice in a sample of 639 university students (321 men and 318 women), mean age 21.43 years (+/- 2.78). Physical fitness self-perception, physical activity history, and coach's support to practice physical activity have a direct effect on the practice of physical activity and an indirect effect on future intention to practice, both in men and women. The practice of physical activity has also a direct effect on future intention to practice. Likewise, the participation in sport competitions predicts practice of physical activity and future intention in men, whereas being a member of a sports club predicts practice and future intention in women.

Perceptual-cognitive skills and performance in orienteering.

The goal was analysis of the perceptual-cognitive skills associated with sport performance in orienteering in a sample of 22 elite and 17 nonelite runners. Variables considered were memory, basic orienteering techniques, map reading, symbol knowledge, map-terrain-map identification, and spatial organisation. A computerised questionnaire was developed to measure the variables. The reliability of the test (agreement between experts) was 90%. Findings suggested that competence in performing basic orienteering techniques efficiently was a key variable differentiating between the elite and the nonelite athletes. The results are discussed in comparison with previous studies.

[Validation of eating habits subscale in children (sehan: spanish version) from 10 to 12 years]. / Validación de la subescala de hábitos alimentarios en niños (SEHAN) de 10 a 12 años.

INTRODUCTION: The vulnerability of children and the current epidemiological situation requires the use of validated instruments to study their eating habits in contexts like home and school. OBJECTIVE: Validating a subscale Eating Habits in Children, aged between 10 and 12 years. METHOD: To study the validity and the internal logic of the instrument, 5 experts rated each item and afterwards, the canonical coefficient concordance (CCC) was calculated. 134 students completed the subscale two times to ensure the study consistency and reliability. The Intraclass Correlation Coefficient (ICC), the Spearman Correlation Coefficient (SCC) and Wilcoxon test were calculated. 187 students were involved for the criterion validity. The SCC between BMI and triceps skinfold (TS) was assessed with the final subscale score. RESULT: The subscale was finally composed by 27 items. The experts score was 3.94 (out of 4 possible points). The CCC was 83.04%. Wilcoxon result was (p<.05) to each item. Result of ICC> .06 was obtained to 81.86% of the subscale. The ICC was (range 467-914)for 25 out of the 27 items. The CCS was (range 350-777)(p <.01) in 25 out of the 27 variables. The SCC for criteria validity of de Subescale with BMI and PLT was in both cases (p<.05). CONCLUSIONS: It is proven that this subscale is a valid instrument, reliable, simple, with fast delivery and easy understanding.

Introducción: La vulnerabilidad de los niños y la actual situación epidemiológica, hace necesarioel uso de instrumentos validados para estudiar sus hábitos alimenticios tanto en contextos familiares como en escolares. Objetivo: Validar una Subescala de Hábitos Alimentarios en Niños (SEHAN), de 10 a 12 años. Método: Se validó el instrumento y sus ítems por cinco expertos y apartir de estas valoraciones se calculó el coeficiente de concordancia canónica (CCC). Para la fiabilidad y consistencia interna, 134 estudiantes completaron dos veces la subescala y se calculó el Coeficiente de Correlación Intraclase (CCI), el Coeficiente de Correlación de Spearman (CCS) y el test Wilcoxon. Para la validez criterial se halló el CCS de 187 alumnos. Se valoró la correlación entre IMC y pliegue tricipital (PLT) con la puntuación final de la SEHAN. Resultado: La SEHANquedó compuesta por 27 ítems. La puntuación de los expertos fue de 3.94 (sobre 4 puntos posibles). El CCC fue del 83.04%. El resultado del test de Wilcoxon, fue (p< .05). Para el 81.86% de la subescalase obtuvo un CCI>.06. El CCI rango fue .467 - .914 para 25 de los 27 ítems. El CCS rango fue .350 - .777 (p< .01) en 25 de las 27 variables. El CCS para la validez criterial de la SEHAN con IMCy PLT en ambos casos fue (p< .05). Conclusiones: La SEHAN demostró ser un instrumento válido, fiable, sencillo, de rápida administración y fácil compresión.

Effects of a rhythmic and choreographic program in obese and overweight participants.

INTRODUCTION: Currently there is a growing trend in the prevalence of overweight and obesity. This increased prevalence trend leads to an increase in the costs of health care. OBJECTIVE: The aim of the present study was to analyze the effects on physical fitness and bone mineral density through an intervention program of physical activity based on rhythmic and choreographic activities in an overweight and obese population. METHOD: An 8-month physical activity based on rhythmic and choreographic activities was conducted in overweight and obese people. Thirty-four participants aged 50.43 ± 10.57 with a body mass index (BMI) 38.37 ± 4.82 took part in the physical activity program. This study assesses the effects of fitness, percentage of body fat and bone mineral density (BMD). RESULTS: After an 8-month physical activity intervention program based on rhythmic and choreographic activities, significant differences were found in: percentage of body fat (p = 0.004), aerobic capacity (p = 0.023), flexibility of the lower limbs (flexibility in the right leg p = 0.029 and left leg p = 0.002), balance (p < 0.001), strength in lower limbs (p = 0..003) and strength in upper limbs (p < 0.001). Besides that, significant differences were found in parameters related with BMD such as T-Score (p = 0.025) and Z-Score (p = 0.012), Bone Quality Index (BQI) (p = 0.026) and an increase in Broadband Ultrasound Attenuation (BUA) although not a statistically significant one (p = 0.939). CONCLUSIONS: These findings suggest that a physical activity program based on rhythmic and choreographic activities can act as a preventive method of mobility and fragility, as well as preventing bone loss.

Introducción: Actualmente hay una tendencia creciente en la prevalencia del sobrepeso y la obesidad. Esta tendencia creciente en la prevalencia de la obesidad conduce a un aumento en los costos de la atención sanitaria. Objetivo: El objetivo del presente estudio fue analizar los efectos sobre la aptitud física y la densidad mineral ósea a través de un programa de intervención de actividad física basado en actividades rítmicas y coreográficas en una población con sobrepeso y obesidad. Método: 8 meses de actividad física basada en actividades rítmicas y coreográficas fue llevado a cabo en personas con sobrepeso y obesidad. Treinta y cuatro participantes de 50.43 ± 10.57 años y con un índice de masa corporal (IMC) de 38.37 ± 4.82 participaron en el programa de actividad física. Este estudio evalúa los efectos sobre la aptitud física, el porcentaje de grasa corporal y la densidad mineral ósea (DMO). Resultados: Después de un programa de intervención de actividad física de 8 meses basado en actividades rítmicas y coreográficas, se encontraron diferencias significativas en: el porcentaje de grasa corporal (p = 0.004), la capacidad aeróbica (p = 0.023), la flexibilidad de las extremidades inferiores (flexibilidad en la pierna derecha p = 0.029 y en la pierna izquierda p = 0.002), el equilibrio (p.

Kinematical analysis of the snatch in elite male junior weightlifters of different weight categories.

The purpose of this study was to analyze the differences in the technical pattern of the snatch in elite junior weightlifters of different weight categories. The sample was a group of 33 men weightlifters from different weight categories. The comparative study included 2 groups, taking into account weight categories. Group A included 17 weightlifters from the lightest categories, 56 and 62 kg; group B included 16 weightlifters from the heaviest categories, 85 and 105 kg. Three-dimensional photogrammetry technique was utilized. Regarding group differences, we can conclude that lifters belonging to heavier categories are more efficient, as they manage to have longer barbell propulsion trajectories, which allows them to exert actions on the barbell for a longer period, especially in the initial lifting phase. They attain greater barbell vertical velocity (p = 0.029), a longer vertical bar trajectory normalized on first pull (p = 0.011), and a greater, although limited, bar height loss on the catch (p = 0.008). Besides, intergroup differences evidence that heavier category lifters observe a different temporal organization of the movement based on a longer first pull (p = 0.000), a shorter transition (p = 0.030), and a longer turnover (p = 0.049). No significant differences were found in the analyzed angular parameters during the first and second pull. We believe the intergroup differences found not to be determining enough to consider a technical model adapted to the characteristics of each body weight category. This confirms that a successful lift is multifactor based and individual dependent. Given its transcendence, this evidence should be taken into account in the technical training of young lifters.