73 research outputs found
Electron injection and interfacial trap passivation in solution-processed organic light-emitting diodes using a polymer zwitterion interlayer
Treating Velopharyngeal Insufficiency in a Case of Substance Abuse: A New Client Population
Exercise-to-rest ratios in repeated sprint ability training in women's soccer
BACKGROUND: The aim of this study was to investigate the applicability of three different exercise-to-rest ratios in repeated sprint ability (RSA) training in women's soccer players, applying those which are usually adopted in male adult and young players, when performing three different sprinting modes (straight, shuttle, and sprinting with changing of direction). METHODS: Fifteen trained female soccer players (height: 1.65±0.06 m; weight: 59.3±9.0 kg; BMI 21.6±2.7 kg/m2; age: 23.3±5.9 years) participated to the study. In order to compare the different values of the time recorded, an index of fatigue (IF%) was used. Recovery times among trials in the sets were administered according to the 1:5, 1:3, 1:2 exercise-to-rest ratio, respectively. Blood lactate concentrations at the end of each set were analyzed. RESULTS: Significant differences among trials within each set (repeated measures ANOVA; P<0.05) were found, as evidence of fatigue over time, with an average decay of performance of about 5% but no significant differences were found in IF%, among the three different sprinting modalities when applying the investigated exercise-to-rest ratios (factorial ANOVA; P>0.05). Significant differences were found in blood lactate concentrations (P<0.05). CONCLUSIONS: The results of this study confirm that the exercise-to-rest ratios considered in this study might be suitable to design effective testing protocols and training sessions aimed at the development of the RSA in women's soccer players, keeping the performances in the speed domain (IF% <7-8%) but inducing the fatigue processes sought with this kind of training method
Diketopyrrolopyrrole-Polymer Meets Thiol-Ene Click Chemistry: A Cross-Linked Acceptor for Thermally Stable Near-Infrared Photodetectors
Acute effects of two different initial heart rates on testing the Repeated Sprint Ability in young soccer players
Aim. The aim of this paper was to investigate the acute effects of two different initial heart rates intensities when testing the repeated sprint ability (RSA) performances in young soccer players.
Methods. Since there are many kinds of pre-match warmups, we chose to take as an absolute indicator of internal load the heart rate reached at the end of two different warmup protocols (60 vs. 90% HRmax) and to compare the respective RSA performances. The RSA tests were performed on fifteen male soccer players (age: 17.9 +/- 1.5 years) with two sets of ten shuttle-sprints (15+15 m) with a 1:3 exercise to rest ratio, in different days (randomized order) with different HR% (60 & 90% HRmax). In order to compare the different sprint performances a Fatigue Index (FI%) was computed, while the blood lactate concentrations (BLa-) were measured before and after testing, to compare metabolic demand.
Results. Significant differences among trials within each sets (P<0.01) were found. Differences between sets were also found, especially comparing the last five trials for each set (Factorial ANOVA; P<0.01), effect size values confirming the relevance of these differences. Although the BLa- after warmup was higher (36%) between 90% vs. 60% HRmax, after the RSA test the differences were considerably low (7%).
Conclusion. Based on physiological information's this methodological approach (testing with initial 90 %HR.) reflects more realistically the metabolic background in which a soccer player operates during a real match. This background may be partially reproduced by warming up protocols that, by duration and metabolic commitment, can reproduce conveniently the physiological conditions encountered in a real game (e.g. HRmax approximate to 85-95 %; BLa->4 mmol/L-1)
The Use of Nonspeech Oral Motor Exercises in the Treatment of Children With Cleft Palate: A Re-Examination of Available Evidence
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