Efectos de la competición sobre la fuerza dinámica máxima en el jugador de tenis de élite. Estudio de un caso

El objetivo de este artículo es mostrar los efectos de la competición sobre la fuerza dinámica máxima (FDM) en una jugadora de tenis de 15 años de edad que obtuvo importantes resultados deportivos (actualmente top 100 del ranking WTA). Para ello, se presentan las mejoras de la FDM después de realizar un entrenamiento con sobrecargas durante 12 semanas y se comparan con los valores de FDM medidos durante el periodo competitivo. El tenis es un deporte que requiere desarrollar elevados niveles de fuerza repetidas veces en cortos periodos de tiempo. La potencia es la habilidad del sistema neuromuscular para producir el mayor impulso posible en un tiempo dado. Este espacio de tiempo depende de la carga a la que nos oponemos (en el tenis, la raqueta, el impacto de la pelota y el peso del cuerpo durante el desplazamiento) y de las necesidades de aceleración del movimiento. Algunos estudios realizados con electromiografía han observado que en el tenis la fuerza de impacto de la pelota esta determinada por la activación neuromuscular en las primeras fases de aceleración del brazo en cada tipo de golpe, pero que sin embargo se trata de un movimiento no balístico. Posiblemente por ello, ante la necesidad de activar el músculo de forma máxima en el menor tiempo posible los tenistas deberían tratar de mejorar y mantener la FDM en determinadas fases de la temporada. Diversos tests de evaluación de la condición física pueden facilitar al preparador físico información específica sobre la condición física de los tenistas y sobre su evolución con el entrenamiento. En el caso que presentamos, se midió la FDM de los músculos mayormente implicados en la ejecución de los distintos tipos de golpe utilizando los tests de fuerza que según la bibliografía especializada son más específicos para el tenis

Efectes de la competició sobre la força dinàmica màxima en el jugador de tennis d’elit. Estudi d’un cas

L’objectiu d’aquest article és mostrar els efectes de la competició sobre la força dinàmica màxima (FDM) en una jugadora de tennis de 15 anys d’edat que va obtenir importants resultats esportius (actualment top 100 del rànquing WTA). Per fer-ho, es presenten les millores de la FDM després de realitzar un entrenament amb sobrecàrregues durant 12 setmanes i es comparen amb els valors de FDM mesurats durant el període competitiu. El tennis és un esport que requereix desenvolupar elevats nivells de força repetidament en períodes de temps curts. La potència és l’habilitat del sistema neuromuscular per produir el major impuls possible en un temps donat. Aquest espai de temps depèn de la càrrega a què ens oposem (en el tennis, la raqueta, l’impacte de la pilota i el pes del cos durant el desplaçament) i de les necessitats d’acceleració del moviment. Alguns estudis realitzats amb electromiografia han observat que en el tennis la força d’impacte de la pilota ve determinada per l’activació neuromuscular en les primeres fases d’acceleració del braç en cada tipus de cop, però que tanmateix, es tracta d’un moviment no balístic. Possiblement per això, davant la necessitat d’activar el múscul de forma màxima en el mínim de temps possible, els tennistes haurien de tractar de millorar i mantenir la FDM en determinades fases de la temporada. Diversos tests d’avaluació de la condició física poden facilitar al preparador físic informació específica sobre la condició física dels tennistes i sobre la seva evolució amb l’entrenament. En el cas que presentem, es va mesurar la FDM dels músculs més implicats en l’execució dels diferents tipus de cop; vam utilitzar els tests de força que, segons la bibliografia especialitzada, són més específics per al tennis

Iliopsoas and Gluteal Muscles Are Asymmetric in Tennis Players but Not in Soccer Players

To determine the volume and degree of asymmetry of iliopsoas (IL) and gluteal muscles (GL) in tennis and soccer players.IL and GL volumes were determined using magnetic resonance imaging (MRI) in male professional tennis (TP) and soccer players (SP), and in non-active control subjects (CG) (n = 8, 15 and 6, respectively).The dominant and non-dominant IL were hypertrophied in TP (24 and 36%, respectively, P<0.05) and SP (32 and 35%, respectively, P<0.05). In TP the asymmetric hypertrophy of IL (13% greater volume in the non-dominant than in the dominant IL, P<0.01) reversed the side-to-side relationship observed in CG (4% greater volume in the dominant than in the contralateral IL, P<0.01), whilst soccer players had similar volumes in both sides (P = 0.87). The degree of side-to-side asymmetry decreased linearly from the first lumbar disc to the pubic symphysis in TP (r = -0.97, P<0.001), SP (r = -0.85, P<0.01) and CG (r = -0.76, P<0.05). The slope of the relationship was lower in SP due to a greater hypertrophy of the proximal segments of the dominant IL. Soccer and CG had similar GL volumes in both sides (P = 0.11 and P = 0.19, for the dominant and contralateral GL, respectively). GL was asymmetrically hypertrophied in TP. The non-dominant GL volume was 20% greater in TP than in CG (P<0.05), whilst TP and CG had similar dominant GL volumes (P = 0.14).Tennis elicits an asymmetric hypertrophy of IL and reverses the normal dominant-to-non-dominant balance observed in non-active controls, while soccer is associated to a symmetric hypertrophy of IL. Gluteal muscles are asymmetrically hypertrophied in TP, while SP display a similar size to that observed in controls. It remains to be determined whether the different patterns of IL and GL hypertrophy may influence the risk of injury

Muscle Hypertrophy in Prepubescent Tennis Players: A Segmentation MRI Study

PURPOSE: To asses if tennis at prepubertal age elicits the hypertrophy of dominant arm muscles. METHODS: The volume of the muscles of both arms was determined using magnetic resonance imaging (MRI) in 7 male prepubertal tennis players (TP) and 7 non-active control subjects (CG) (mean age 11.0 ± 0.8 years, Tanner 1-2). RESULTS: TP had 13% greater total muscle volume in the dominant than in the contralateral arm. The magnitude of inter-arm asymmetry was greater in TP than in CG (13 vs 3%, P<0.001). The dominant arm of TP was 16% greater than the dominant arm of CG (P<0.01), whilst non-dominant arms had similar total muscle volumes in both groups (P = 0.25), after accounting for height as covariate. In TP, dominant deltoid (11%), forearm supinator (55%) and forearm flexors (21%) and extensors (25%) were hypertrophied compared to the contralateral arm (P<0.05). In CG, the dominant supinator muscle was bigger than its contralateral homonimous (63%, P<0.05). CONCLUSIONS: Tennis at prepubertal age is associated with marked hypertrophy of the dominant arm, leading to a marked level of asymmetry (+13%), much greater than observed in non-active controls (+3%). Therefore, tennis particpation at prepubertal age is associated with increased muscle volumes in dominant compared to the non-dominant arm, likely due to selectively hypertrophy of the loaded muscles

Large Asymmetric Hypertrophy of Rectus Abdominis Muscle in Professional Tennis Players

Purpose: To determine the volume and degree of asymmetry of the musculus rectus abdominis (RA) in professional tennis players. Methods: The volume of the RA was determined using magnetic resonance imaging (MRI) in 8 professional male tennis players and 6 non-active male control subjects. Results: Tennis players had 58 % greater RA volume than controls (P = 0.01), due to hypertrophy of both the dominant (34% greater volume, P = 0.02) and non-dominant (82 % greater volume, P = 0.01) sides, after accounting for age, the length of the RA muscle and body mass index (BMI) as covariates. In tennis players, there was a marked asymmetry in the development of the RA, which volume was 35 % greater in the non-dominant compared to the dominant side (P,0.001). In contrast, no sideto-side difference in RA volume was observed in the controls (P = 0.75). The degree of side-to-side asymmetry increased linearly from the first lumbar disc to the pubic symphysis (r = 0.97, P,0.001). Conclusions: Professional tennis is associated with marked hypertrophy of the musculus rectus abdominis, which achieves a volume that is 58 % greater than in non-active controls. Rectus abdominis hypertrophy is more marked in the non-dominant than in the dominant side, particularly in the more distal regions. Our study supports the concept that humans can differentially recruit both rectus abdominis but also the upper and lower regions of each muscle. It remains to b

Interplay of muscle architecture, morphology, and quality in influencing human sprint cycling performance: A systematic review

Background: This systematic review aimed to discern the relationships between muscle morphology, architecture, and quality with sprint cycling performance while considering the multifaceted nature of these relationships across diverse studies. Methods: Employing the PRISMA guidelines, an exhaustive search was performed across four primary databases: MEDLINE/PubMed, Web of Science, CINAHL Complete, and SPORTDiscus. The Methodological Index For Non-Randomised Studies (MINORS) was used to assess the methodological quality of the included studies. Out of 3971 initially identified records, only 10 studies met the eligibility criteria. Results: These investigations underscored the robust relationship of quadriceps muscle volume with peak power output (R2 from 0.65 to 0.82), suggesting its pivotal role in force production. In muscle architecture, the pennation angle and fascicle length showed varied associations with performance. Furthermore, muscle quality, as denoted by echo intensity, showed preliminary evidence of a potential inverse relationship with performance. The methodological quality assessment revealed varied scores, with the most consistent reporting on the aim, endpoints, and inclusion of consecutive patients. However, limitations were observed in the prospective calculation of study size and unbiased assessment of study endpoints. Conclusion: Our findings indicate that muscle volume is a major determinant of sprint cycling performance. Muscle architecture and quality also impact performance, although in a more intricate way. The review calls for standardised methodologies in future research for a more comprehensive understanding and comparability of results. PROSPERO registration number: CRD42023432824 (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=432824)

Soccer Attenuates the Asymmetry of Rectus Abdominis Muscle Observed in Non-Athletes

Purpose: To determine the volume and degree of asymmetry of the rectus abdominis muscle (RA) in professional soccer players. Methods: The volume of the RA was determined using magnetic resonance imaging (MRI) in 15 professional male soccer players and 6 non-active male control subjects. Results: Soccer players had 26% greater RA volume than controls (P<0.05), due to hypertrophy of both the dominant (28% greater volume, P<0.05) and non-dominant (25% greater volume, P<0.01) sides, after adjusting for age, length of the RA muscle and body mass index (BMI) as covariates. Total volume of the dominant side was similar to the contralateral in soccer players (P = 0.42) and in controls (P = 0.75) (Dominant/non-dominant = 0.99, in both groups). Segmental analysis showed a progressive increase in the degree of side-to-side asymmetry from the first lumbar disc to the pubic symphysis in soccer players (r = 0.80, P<0.05) and in controls (r = 0.75, P<0.05). The slope of the relationship was lower in soccer players, although this trend was not statistically significant (P = 0.14). Conclusions: Professional soccer is associated with marked hypertrophy of the rectus abdominis muscle, which achieves a volume that is 26% greater than in non-active controls. Soccer induces the hypertrophy of the non-dominant side in proximal regions and the dominant side in regions closer to pubic symphysis, which attenuates the pattern of asymmetry of rectus abdominis observed in non-active population. It remains to be determined whether the hypertrophy of rectus abdominis in soccer players modifies the risk of injury

Greater tibial bone strength in male tennis players than controls in the absence of greater muscle output

© 2015 Chinese Speaking Orthopaedic Society. Background/Objective: The greatest forces experienced by bones result from muscular contractions-muscles produce most force in high-velocity eccentric contractions. Bouncing movements, e.g., sprinting or hopping-where such contractions occur-are highly beneficial for lower limb bones. However, there is a growing body of evidence that torsional stresses are highly osteogenic. Sports in which frequent quick turning occurs-hence large torsional stresses can be expected-e.g., tennis, may also improve bone strength even in the absence of large ground reaction and muscle forces. Methods: To investigate the relative effects of bouncing and turning movements on bones, we recruited 47 older men (mean age 62.4±12.9 years). They were competitive sprinters (representing exposure to bouncing movement), competitive tennis players (turning movements), and inactive controls. Peripheral quantitative computed tomography scans of tibial diaphysis at 66% distal-proximal length were taken; muscle sizes from peripheral quantitative computed tomography and countermovement jump performance were also examined. Results: Bone strength of tennis players was clearly greater than that of controls (23% greater bone mass; p0.5). Material eccentricity analysis suggests that torsional stresses may be a significant adaptive stimulus to tibial bone. Conclusion: Results suggest that sports with quick turning movements are highly osteogenic, even in the absence of greater muscular output. This may be related to the large torsional stresses produced during turning movements

Physical fitness reference standards for preschool children: The PREFIT project

Objectives Reference values are necessary for classifying children, for health screening, and for early prevention as many non-communicable diseases aggravate during growth and development. While physical fitness reference standards are available in children aged 6 and older, such information is lacking in preschool children. Therefore, the purposes of this study were (1) to provide sex-and age-specific physical fitness reference standards for Spanish preschool children; and (2) to study sex differences across this age period and to characterise fitness performance throughout the preschool period. Design Cross-sectional. Methods A total of 3179 preschool children (1678 boys) aged 2.8–6.4 years old from Spain were included in the present study. Physical fitness was measured using the PREFIT battery. Results Age- and sex-specific percentiles for the physical fitness components are provided. Boys performed better than girls in the cardiorespiratory fitness, muscular strength, and speed-agility tests over the whole preschool period studied and for the different percentiles. In contrast, girls performed slightly better than boys in the balance test. Older children had better performance in all fitness tests than their younger counterparts. Conclusions Our study provides age- and sex-specific physical fitness reference standards in preschool children allowing interpretation of fitness assessment. Sexual dimorphism in fitness tests exists already at preschool age, and these differences become larger with age. These findings will help health, sport, and school professionals to identify preschool children with a high/very low fitness level, to examine changes in fitness over time, and to analyse those changes obtained due to intervention effects

Prevalence of severe/morbid obesity and other weight status and anthropometric reference standards in Spanish preschool children: The PREFIT project

BACKGROUND: Childhood obesity has become a major health problem in children under the age of 5 years. Providing reference standards would help paediatricians to detect and/or prevent health problems related to both low and high levels of body mass and to central adiposity later in life. Therefore, the aim of this study was to examine the prevalence of different weight status categories and to provide sex- and age-specific anthropometry reference standards for Spanish preschool children. METHODS: A total of 3178 preschool children (4.59±0.87 years old) participated in this study. Prevalence of different degrees of obesity (mild, severe, and morbid) and other weight status categories were determined. RESULTS: Reference standards were obtained. Prevalence of overweight and obese preschool children in the Spanish population ranged from 21.4 to 34.8%. Specifically, the obesity prevalence was 3.5, 1.2, and 1.3% of these subjects were categorized as mild, severe, and morbid obese. Sex- and age-specific reference standards for anthropometric parameters are provided for every 0.25 years (i.e. every trimester of life). CONCLUSION: Our results show a high prevalence of overweight/obese preschoolers. The provided sex- and age-specific anthropometric reference standards could help paediatricians to track and monitor anthropometric changes at this early stage in order to prevent overweight/obesity.We thank the participation of the preschoolers, parents, and teachers in this study. We are grateful to Ms. Carmen Sainz-Quinn for assistance with the English language. This work is part of a Ph.D. Thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain. The PREFIT project takes place owing to the funding of the Ramón y Cajal grant held by FBO (RYC-2011-09011). C.C.-S. is supported by a grant from the Spanish Ministry of Economy and Competitiveness (BES-2014-068829). E.G.A. and F.B.O. are supported by a grant from the Spanish Ministry of Science and Innovation (RYC-2014-16390 and RYC-2011-09011, respectively). C.A.-B., A.P.-B., and G.S.-D. are supported by the Spanish Ministry of Education (FPU13/03137, FPU15/ 05337, and FPU13/04365, respectively). Additional funding was obtained from the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES) and by the Junta de Andalucia, Consejería de Conocimiento, Investigación y Universidades. In addition, funding was provided by the SAMID III network, RETICS, the PN I+D+I 2017-2021 (Spain), ISCIII-Sub-Directorate General for Research Assessment and Promotion, the European Regional Development Fund (ERDF) (RD16/0022, SOMM17/6107/UGR), the EXERNET Research Network on Exercise and Health in Special Populations (DEP2005- 00046/ACTI), the University of the Basque Country (GIU14/21), and the University of Zaragoza (JIUZ-2014-BIO-08)