5,106 research outputs found
The effects of man-marking on work intensity in small-sided soccer games
The aim of this study was to examine the effect of manipulating defensive rules: with and without man-marking (MM and NMM) on exercise intensity in 3 vs. 3 small-sided games (SSGs). Twelve adolescent soccer players (age: 16.2 ± 0.7 years; body mass: 55.7 ± 6.4 kg; body height: 1.70 ± 0.07 m) participated in this repeated measures study. Each participant performed in four different SSGs formats: 3 vs. 3 MM with and without goals and 3 vs. 3 NMM with and without goals. Each SSG lasted 3 x 4 minutes interspersed with 4 minutes passive recovery. The percentage heart rate reserve (%HRreserve) was recorded continuously during SSG and session-rating of perceived exertion (session-RPE) after the SSG. MANOVA showed that defensive rule had significant effects on intensity (F = 5.37, p < 0.01). Specifically, MM during SSG induced significantly higher %HRreserve compared to NMM (Goal: 80.5 vs. 75.7%; No goal: 80.5 vs. 76.1%; p < 0.05, effect size = 0.91-1.06), irrespective of the presence or absence of goals. However, only MM with the presence of goals induced significant higher session-RPE compared to NMM (7.1 vs. 6.0; p < 0.05, effect size = 1.36), whereas no difference in session-RPE was observed
between MM and NMM (7.4 vs. 6.9; p > 0.05, effect size
= 0.63) when no goals were used. Higher intra-class reliability and lower coefficient of variation values were also reported in MM as compared to NMM. This study in youth soccer players shows there is ~4.5% increase in heart rate response by using the man-marking in 3 vs. 3 SSG thus the intensity of SSG can be significantly increased when using man-marking tactics
Wave-packet treatment of neutrino oscillations and its implications on determining the neutrino mass hierarchy
We derive the neutrino flavor transition probabilities with the neutrino
treated as a wave packet. The decoherence and dispersion effects from the
wave-packet treatment show up as damping and phase-shifting of the plane-wave
neutrino oscillation patterns. If the energy uncertainty in the initial
neutrino wave packet is larger than around 0.01 of the neutrino energy, the
decoherence and dispersion effects would degrade the sensitivity of reactor
neutrino experiments to mass hierarchy measurement to lower than 3
confidence level
Pinning modes and interlayer correlation in high magnetic field bilayer Wigner solids
We report studies of pinning mode resonances in the low total Landau filling
(\nu) Wigner solid of a series of bilayer hole samples with negligible
interlayer tunneling, and with varying interlayer separation d. Comparison of
states with equal layer densities (p,p) to single layer states (p,0) produced
{in situ} by biasing, indicates that there is interlayer quantum correlation in
the solid at small d. Also, the resonance frequency at small d is decreased
just near \nu=1/2 and 2/3, indicating the importance in the solid of
correlations related to those in the fractional quantum Hall effects
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