24 resultados para Vocal warm-up

em Deakin Research Online - Australia


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objectives: To determine whether a golf specific warm up programme (both immediately prior to play and after performing it five times a week for 5 weeks) improved performance in 10 male golfers compared with 10 controls matched for age, sex, and handicap.

Methods: Twenty male golfers were matched for age (±2 years) and handicap (±1 stroke). Club head speed was assessed by two dimensional video analysis in a laboratory setting. In week 1, all golfers performed 10 strokes. In weeks 2 and 7, the controls underwent the same procedure as in week 1. The exercise group performed the golf specific warm up followed by their 10 strokes. Between weeks 2 and 7, the exercise group performed the specially designed warm up five times a week for 5 weeks.

Results: The mean club head speeds of the exercise group improved at each testing week. Between weeks 1 and 2, golfers in the exercise group improved their club head speed on average by 3–6 m/s (12.8%), and between weeks 1 and 7, they increased their club head speeds by 7–10 m/s (24.0%). With the exception of one golfer whose club head speed varied by 1.7 m/s, the mean club head speeds of the golfers in the control group hardly varied over the testing period (range: 0.3–0.8 m/s). A significant difference (p = 0.029) was found between the mean club head speeds of the exercise and control groups over the duration of the study, and a significant interaction over time (p<0.001) was also found.

Conclusions: This study has shown that golfers’ performances will be significantly improved by undertaking a golf specific warm up programme compared with not performing the warm up.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Evidence suggests that static stretching inhibits muscular power. However, research does not reflect practice whereby individuals follow up stretching with secondary activity. This study investigated muscular power following stretching, and after a second bout of activity. Participants (n = 13) completed 3 randomized testing sessions which included a 5 min warm-up, followed by a vertical jump (VJ) on a force platform; an intervention (static stretching, dynamic, or control), followed by a second VJ. Participants then completed a series of movements, followed by a VJ, up to 60 min post activity. Immediately following the intervention, there was a 10.7% difference in VJ between static and dynamic stretching. The second warm up bout increased VJ height following the dynamic intervention, whereas the static stretching condition did not show any  differences. The novel finding from this study demonstrates a second exercise bout does not reverse the effects of static stretching and is still detrimental to VJ.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This research investigates whether club head speed is a valid determinant of golfing performance and the effects of a golf-specific warm-up program on club-head speed in male golfers in the immediate and short term (five-week)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cold start driving cycles exhibit an increase in friction losses due to the low temperatures of metal and media compared to normal operating engine conditions. These friction losses are responsible for up to 10% penalty in fuel economy over the official drive cycles like the New European Drive Cycle (NEDC), where the temperature of the oil even at the end of the 1180 s of the drive cycle is below the fully warmed up values of between 100°C and 120°C. At engine oil temperatures below 100°C the water from the blow by condensates and dilutes the engine oil in the oil pan which negatively affects engine wear. Therefore engine oil temperatures above 100°C are desirable to minimize engine wear through blow by condensate. The paper presents a new technique to warm up the engine oil that significantly reduces the friction losses and therefore also reduces the fuel economy penalty during a 22°C cold start NEDC. Chassis dynamometer experiments demonstrated fuel economy improvements of over 7% as well as significant emission reductions by rapidly increasing the oil temperature. Oil temperatures were increased by up to 60°C during certain parts of the NEDC. It is shown how a very simple sensitivity analysis can be used to assess the relative size or efficiency of different heat transfer passes and the resulting fuel economy improvement potential of different heat recovery systems system. Due to its simplicity the method is very fast to use and therefore also very cost effective. The method demonstrated a very good correlation for the fuel consumption within ±1% compared to measurements on a vehicle chassis roll.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This review presents the methods used to investigate the effects of various stretching protocols on muscular force and performance, in light of current individual and elite athlete stretching practices in their warm-up routines. A meta-analysis of peer-reviewed articles between the years of 2000 and 2007 revealed the majority of studies support the notion that static stretching is detrimental to muscular force and performance. However, the meta-analysis also revealed that the protocols used do not necessarily match current practice with many elite athletes. This article proposes, based on the mismatch between research and practice, that further studies must address this issue in further exploring the role of stretching in pre-training and competition warm-up routines.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Most simulation textbooks assume that a model can be started in an empty state and the final output will not be affected, so long as the "warm-up period" is excluded from the analysis. In this paper we test this assumption, using a discrete-event model of a existing manufacturing facility. Using a series of model runs with no initial Work in Progress (WIP) and another series of simulation runs with a realistic initial level of WIP, the results can be compared and contrasted. While the results show similar shaped profiles in terms of throughput and lead time, the differences between the curves has important practical implications.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This paper advocates the effectiveness of a dual technique model of interviewing, which combines narrative and depth interview techniques, within the case study method in a cross-cultural management research setting, an Australian MNC operating in China. The case study is acknowledged to be a highly appropriate method for gaining insight into the complicated area of cross-cultural management enquiry in order to generate new theories. In this context, we propose a model which combines the narrative and the depth interview techniques in the interview process, and have illustrated its usefulness with material drawn from the China-Australia cross-cultural research interface.

After establishing the rationale for the model, the discussion focuses on the practicalities of applying it in interviews, in relation to the preparation, warm-up and trust building phases, and in the exercise of personal interviewing skills in cross-cultural research, in this case, the advantage of the interviewer being bilingual.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Latest trends in waste heat recovery include systems like Thermo Electric Generation (TEG), Rankine cycle, and active warm up systems. The advantages and disadvantages of different approaches are critically discussed and compared with a novel and effective oil heating system that can deliver between 7% and 12% reductions of CO2 emissions and fuel consumption. The comparison includes the expected CO2 and fuel saving potential related to the legal drive cycle as well as real world driving, effects on regulated exhaust emissions, utilisation of resources, maintenance and service, vehicle performance, comfort, noise, and durability.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Internal combustion engines release about 1/3 of the energy bound in the fuel as exhaust waste gas energy and another 1/3 energy is wasted through heat transfer into the ambient. On the other hand losses through friction are the third largest root cause for energy loss in internal combustion engines. During city driving frictional losses can be of the same size as the effective work, and during cold start these losses are even bigger. Therefore it is obvious to utilise wasted exhaust energy to warm up the engine oil directly. Frictional losses of any engine can be reduced during part load. Sensitivity analyses have been conducted for different concepts that utilise exhaust energy to reduce engine viscosity and friction. For a new system with an exhaust gas/oil heat exchanger the following benefits have been demonstrated:

• Fuel consumption reductions of over 7% measured as an average over 5 NEDC tests
compared to the standard system configuration.
• Significant reductions in exhaust emissions, mainly CO and NOx have been achieved
• Significantly higher oil temperatures during cold start indicate large potential to
reduce engine wear through reduced water condensation in the crankcase
• Fuel consumption reductions of further 3.3% to 4.6% compared to the 7% measured
over the NEDC test can be expected under real world customer usage conditions at
lower ambient temperatures.

Oil temperature measurements and analysis resulted in the idea of a novel system with further potential to reduce fuel consumption. This Oil Viscosity Energy Recovery System (OVER 7™) consists of 3 key features that add significant synergies if combined in a certain way: an oil warm up circuit/bypass, including oil pressure control and Exhaust Gas/Oil Heat Exchanger. The system separates the thermal inertias of the oil in the engine galleries and the oil pan, reduces hydraulic pumping losses, increases the heat transfer from the cylinder head to the oil, and utilises the exhaust heat to reduce oil friction.

The project demonstrated that sensitivity analysis is an important tool for the evaluation of different concepts. Especially for new concepts that include transient heat transfer such a qualitative approach in combination with accurate experiments and measurements can be faster and more efficient in leading to the desired improvements compared to time consuming detailed simulations.