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1.
J Sports Sci ; 41(8): 736-746, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37486001

RESUMO

The study modelled the influence of anthropometric components, climbing-specific power, strength and endurance parameters, flexibility, coordination, and motor planning skills on competitive climbing performance in speed, bouldering, and lead climbing. Sixty-one competitive climbers (26 women [18.1 ± 1.9y], 35 men [21.4 ± 6.1y]) participated. PCA and MRA were used for statistical analyses. Significant predictors for speed climbing performance (R2 = 44% and 35%) were lower (ß = .43 and .47) and upper body power and strength (ß = .40 and .37) for women and men, respectively. For women's bouldering performance (R2 = 39%), they were hip flexibility (ß = .42) and upper body power and strength (ß = .37), for the men's (R2 = 53%) lower (ß = .41) and upper body power (ß = .41) and body fat (ß = .37). For women's lead climbing (R2 = 58%) upper body power and strength (ß = .59) and finger endurance (ß = .48) predict performance, for the men's (R2 = 58%) lower (ß = .36) and upper body power (ß = .28), body fat (ß = .27) and motor planning skills (ß = .27). The multivariate models provide a framework for scientifically grounded climbing training by emphasizing the role of specific performance components.


Assuntos
Montanhismo , Resistência Física , Masculino , Humanos , Feminino , Força da Mão , Extremidade Superior , Dedos , Antropometria
2.
Nanomaterials (Basel) ; 12(18)2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-36144949

RESUMO

A dynamic process model for the simulation of nanoparticle fractionation in tubular centrifuges is presented. Established state-of-the-art methods are further developed to incorporate multi-dimensional particle properties (traits). The separation outcome is quantified based on a discrete distribution of particle volume, elongation and flatness. The simulation algorithm solves a mass balance between interconnected compartments which represent the separation zone. Grade efficiencies are calculated by a short-cut model involving material functions and higher dimensional particle trait distributions. For the one dimensional classification of fumed silica nanoparticles, the numerical solution is validated experimentally. A creation and characterization of a virtual particle system provides an additional three dimensional input dataset. Following a three dimensional fractionation case study, the tubular centrifuge model underlines the fact that a precise fractionation according to particle form is extremely difficult. In light of this, the paper discusses particle elongation and flatness as impacting traits during fractionation in tubular centrifuges. Furthermore, communications on separation performance and outcome are possible and facilitated by the three dimensional visualization of grade efficiency data. Future research in nanoparticle characterization will further enhance the models use in real-time separation process simulation.

3.
Front Sports Act Living ; 4: 902521, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35677360

RESUMO

Performance diagnostics of finger strength is very relevant in climbing. The aim of our study was to find modalities for an intermittent finger flexor muscle endurance test that optimize the correlation of test performance with lead climbing performance. Twenty-seven female and 25 male climbers pulled with 60% MVC and a work-to-rest ratio of 7:2 s on a fingerboard until fatigue. The highest correlations, R = 0.429, were found for women when 9% deviation in the required force and 1 s deviation in the required pulling time was tolerated. For men, the optimum was reached with the same time deviation and a force deviation of 6%, R = 0.691. Together with maximum finger strength the repetitions explained 31.5% of the variance of climbing ability in women and 46.3% in men. Consequences from our results are to tolerate at least 7% force deviation for women and 5% for men and to terminate the finger endurance test quickly after the force falls below the threshold.

4.
Front Sports Act Living ; 4: 790336, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35392592

RESUMO

The analysis of the load structure in competitions is essential to develop performance structure models from which sport-specific testing and training protocols can be derived. The aim of this study was to characterize the external load structure of competitive climbing at an international level in the disciplines of speed, bouldering, lead, and Olympic combined based on video recordings of top athletes. In speed, the route was completed by women with a median of 11 moves and by men with 9 moves that required 0.73 and 0.60 s per move, respectively. Bouldering competitions are characterized by various bouts of activity with resting periods in between. Athletes attempted a boulder problem, a median of 3 times in the qualification and semi-final rounds and 4 times in the final round with an average attempt duration of 27.0 s. In lead, the load structure is characterized by an average climbing time of 4:09 min and 4:18 min, 31.6 and 30.0 actions, contact times of 6.4 s and 6.2 s, and reach times of 1.4 s and 1.6 s for women and men, respectively. Olympic combined competitions combine all 3 single disciplines starting with speed followed by bouldering and lead and are characterized by high competition loads, long durations of almost 3 h, and relatively short resting periods in between.

5.
Nanomaterials (Basel) ; 11(5)2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-33923109

RESUMO

High centrifugal acceleration and throughput rates of tubular centrifuges enable the solid-liquid size separation and fractionation of nanoparticles on a bench scale. Nowadays, advantageous product properties are defined by precise specifications regarding particle size and material composition. Hence, there is a demand for innovative and efficient downstream processing of complex particle suspensions. With this type of centrifuge working in a semi-continuous mode, an online observation of the separation quality is needed for optimization purposes. To analyze the composition of fines downstream of the centrifuge, a UV/vis soft sensor is developed to monitor the sorting of polymer and metal oxide nanoparticles by their size and density. By spectroscopic multi-component analysis, a measured UV/vis signal is translated into a model based prediction of the relative solids volume fraction of the fines. High signal stability and an adaptive but mandatory calibration routine enable the presented setup to accurately predict the product's composition at variable operating conditions. It is outlined how this software-based UV/vis sensor can be utilized effectively for challenging real-time process analytics in multi-component suspension processing. The setup provides insight into the underlying process dynamics and assists in optimizing the outcome of separation tasks on the nanoscale.

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