Strength Gains by Motor Imagery with Different Ratios of Physical to Mental Practice

The purpose of this training study was to determine the magnitude of strength gains following a high-intensity resistance training (i.e., improvement of neuromuscular coordination) that can be achieved by imagery of the respective muscle contraction imagined maximal isometric contraction (IMC training). Prior to the experimental intervention, subjects completed a 4-week standardized strength training program. 3 groups with different combinations of real maximum voluntary contraction (MVC) and mental (IMC) strength training (M75, M50, M25; numbers indicate percentages of mental trials) were compared to a MVC-only training group (M0) and a control condition without strength training (CO). Training sessions (altogether 12) consisted of four sets of two maximal 5-s isometric contractions with 10 s rest between sets of either MVC or IMC training. Task-specific effects of IMC training were tested in four strength exercises commonly used in practical settings (bench pressing, leg pressing, triceps extension, and calf raising). Maximum isometric voluntary contraction force (MVC) was measured before and after the experimental training intervention and again 1 week after cessation of the program. IMC groups (M25, M50, M75) showed slightly smaller increases in MVC (3.0% to 4.2%) than M0 (5.1%), but significantly stronger improvements than CO (−0.2%). Compared to further strength gains in M0 after 1 week (9.4% altogether), IMC groups showed no “delayed” improvement, but the attained training effects remained stable. It is concluded that high-intensity strength training sessions can be partly replaced by IMC training sessions without any considerable reduction of strength gains

Development of a cutting technique modification training program and evaluation of its effects on movement quality and cutting performance in male adolescent American football players

This study developed a cutting technique modification training program and investigated its effects on cutting performance and movement quality in adolescent American football players. For six weeks, an intervention group (IG) of 11 players participated in 25 min cutting technique modification training sessions integrated into team training twice a week, while a control group (CG) of 11 players continued their usual team training. Movement quality was assessed by evaluating 2D high-speed videos, obtained during preplanned 45° and 90° cutting tests, using the Cutting Movement Assessment Score (CMAS) qualitative screening tool. Cutting performance was assessed based on change of direction deficit (CODD). Significant interaction effects of time × group were found for CMAS in 45° and 90° cuttings (p < 0.001, ηp2 = 0.76, p < 0.001, ηp2 = 0.64, respectively), with large improvements in the IG (p < 0.001, g = −2.16, p < 0.001, g = −1.78, respectively) and deteriorations in the CG for 45° cuttings (p = 0.002, g = 1.15). However, no statistically significant differences in CODD were observed pre-to-post intervention. The cutting technique modification training was effective at improving movement quality without impairing cutting performance, and it can be used by practitioners working with adolescent athletes

Development and Trainability of Agility in Youth: A Systematic Scoping Review

Pre-registration and dataset

Einfluss des Ballgewichts auf den Schlagwurf im Handball

Braun J, Büsch D, Schütz C, Sommerfeld W. Einfluss des Ballgewichts auf den Schlagwurf im Handball. In: Büsch D, Heinisch H-D, Lüdemann R, eds. Leistungsfaktoren in den Spiel- und Zweikampfsportarten. Schriftenreihe für Angewandte Trainingswissenschaft. Vol 5. Aachen: Meyer &amp; Meyer; 2016: 89-105

The relationship between motor competence and physical fitness from early childhood to early adulthood : a meta-analysis

Background: Motor competence and physical fitness are important factors for promoting positive trajectories of health over time. In 2008, Stodden and colleagues developed a model that discussed the role of both factors in physical activity. Furthermore, the authors hypothesized that the relationship between motor competence and physical fitness is reciprocal and changes over time. Objective: The aim of the present meta-analysis was to synthesize the evidence on the relationship between motor competence and components of physical fitness from early childhood to early adulthood and the potential influence of age. Methods: Scientific databases Web of Science and PubMed were used for the literature search. German- as well as English-language studies were included that assessed typically developing children. In accordance with the PRISMA guidelines, 93 studies between 2005 and June 2018 were screened in full. Nineteen studies comprising of 32 samples, 87 single data points from 15,984 participants aged 4.5-20.4years (M-age=11.44, SD=4.77) were included in the analysis. Results: A random effects model was conducted for the meta-regression with age as moderator variable. The relationship between motor competence and physical fitness was moderate to large (r=0.43, p<0.001) after controlling for multiple effects, including dependent samples and small sample sizes in the quantitative synthesis. Additionally, age was a small significant positive moderator of the effect size. Conclusions and Implications: The findings provide support for a moderate to large positive relationship between motor competence and physical fitness that strengthens with increasing age. However, the results also indicate that there may be an overlap in content between motor competence and physical fitness assessments, which warrants further investigation. More research is alsoneeded to assess similarities and differences in terms of the construct structures

Uso de la hoja de verificación de Oldenburg para la técnica en tenis de mesa (O3T) como una herramienta para la identificación y desarrollo del talento: un estudio de fiabilidad, validez y factibilidad

Background: The assessment of technical skills as part of a multidimensional approach for talent identification and development in table tennis appears promising. The O3T was developed to assess young table tennis players’ technical skills in a highly representative match situation. In this study, two expert coaches (highest coaching license, 25+ years of professional experience) used the O3T to assess the technical skills of 24 young Dutch table tennis players (9 girls, 15 boys; <12 years) based on video recordings. Results: Results for variables ‘technical quality’, ‘serve quantity’ and ‘stroke quantity’ were analyzed to assess the O3T’s reliability (both inter- and intra-rater), construct validity and feasibility. Bland-Altmanplots and ICCs showed sufficient general reliability with acceptable measurement errors. Variable ‘technical quality’ showed a moderate relationship (r = .44) with overall table tennis performance at T0 in combination with an increasing trend over time, this way indicating high validity. Finally, the O3T proved to be highly feasible with some possibility to improve based on a feasibility questionnaire. Conclusions: Overall, this study presents good prospects for the O3T’s measurements properties. In future, the O3T should be used by coaches in various (talent) contexts to further improve its design and to show its added value for talent activities. Furthermore, this approach could be transferred to other performance aspects and sports.Antecedentes: La evaluación de las habilidades técnicas como parte de un enfoque multidimensional para la identificación y el desarrollo de talentos en el tenis de mesa parece prometedora. La O3T se desarrolló para evaluar las habilidades técnicas de jugadores jóvenes de tenis de mesa en una situación de partido altamente representativa. En este estudio, dos entrenadores expertos (licencia de entrenador más alta, más de 25 años de experiencia profesional) utilizaron la O3T para evaluar las habilidades técnicas de 24 jugadores jóvenes holandeses de tenis de mesa (9 niñas, 15 niños; <12 años) basándose en videos. Resultados: Se analizaron los resultados de las variables “calidad técnica”, “cantidad de saques” y “cantidad de golpes” para evaluar la fiabilidad de la O3T (tanto inter- como intra-evaluador), la validez de constructo y la factibilidad. Los gráficos de Bland-Altman y los CCI mostraron una fiabilidad general suficiente con errores de medición aceptables. La variable “calidad técnica” mostró una relación moderada (r = .44) con el rendimiento general en tenis de mesa en T0 en combinación con una tendencia creciente con el tiempo, indicando así una alta validez. Finalmente, la O3T demostró ser altamente factible con alguna posibilidad de mejora basada en un cuestionario de factibilidad. Conclusiones: En general, este estudio presenta buenas perspectivas de las propiedades de medición de la O3T. En el futuro, la O3T debería ser utilizada por entrenadores en diversos contextos (de talento) para mejorar aún más su diseño y demostrar su valor añadido para las actividades de talento. Además, este enfoque podría transferirse a otros aspectos del rendimiento y a otros deportes.German Federal Institute for Sport Science (Bundesinstitut für Sportwissenschaft; BISp) under Grant 072004/2

Sensory Stimulation of the Triceps Surae Muscle Complex Modulates Spinal Reflex Responses—A Comparison between Tapotement Massage and Repetitive Peripheral Magnetic Stimulation (rPMS)

Background: The reduction of muscular hypertonia is important in the treatment of various diseases or rehabilitation. This study aims to test the efficacy of a 5 Hz mechanical muscle stimulation (tapotement massage) in comparison to a 5 Hz repetitive peripheral magnetic stimulation (rPMS) on the neuromuscular reflex response. Methods: In a randomized control trial, 15 healthy volunteers were administered with either 5 Hz rPMS, tapotement massage, or rPMS sham stimulation. The posterior tibial nerve was stimulated with rPMS and sham stimulation. The Achilles tendon was exposed to a mechanically applied high-amplitude 5 Hz repetitive tendon tapotement massage (rTTM). The tendon reflex (TR) was measured for the spinal response of the soleus muscle. Results: After rPMS, there was a reduction of the TR response (−9.8%, p ≤ 0.034) with no significant changes after sham stimulation. Likewise, TR decreased significantly (−17.4%, p ≤ 0.002) after Achilles tendon tapotement intervention. Conclusions: These findings support the hypothesis that both afferent 5 Hz sensory stimulations contributed to a modulation within the spinal and/or supraspinal circuits, which resulted in a reduction of the spinal reflex excitability. The effects could be beneficial for patients with muscle hypertonia and could improve the functional results of rehabilitation programs