| Objective: The aim of the study was to investigate the physical reactions when people rowing by ergometers in a different combinations of stroke rate and resistance under the condition of the same external power. Then tried to study the cardiorespiratory response and the energy expenditure during the different simulated rowing way.Subject and method: The subjects were 12 males that recruited and selected randomly from the physical education and training major, Shanghai Sport University.Set two kinds of ergometer external power, 100 W and 200 W respectively, under each external power includes three stroke rate and resistance combination, namely:paddle frequency of 30 beats/min, and resistance at 8 level( referred to 30×8combinations); paddle frequency of 40 beats/min, and resistance at 5 levels(referred to40×5 combination); paddle frequency of 50 beats/min and the resistance at the 2 level(referred to 50×2 combinations). Subjects were asked to carry out the six tests and 4minutes per test. During the test subjects were required to follow a metronome, and he should observe the control panel of the ergometer to adjust their power output to achieve and maintain the planned external power. The indicators that needed to be collected consisted of heart rate(HR), oxygen uptake(VO2),energy expenditure values(EE) and blood lactate(Bla). The first three indicators should be collected a30-seconds-data within the time period when the bodily functions had reached a steady state, then use their average to do the analysis. The quiet blood lactate and the blood lactate that three minutes after each test required to test to analyze the performance of different combinations of the stroke rate and resistance under the condition of the same external power.Results:1. 100W: the HR and VO2 of 30×8 combination, 40×5 combination and 50×2combination increased one by one, significant difference existed among compositions(P <0.01); 200W: the HR and VO2 of 40×5 and 50×2 combination was significantly greater than 30×8 combination(P <0.01), no significant difference existed between the 40×5 and 50×2 combination(P > 0.05); the minimum HR and VO2 combinations under the 200 W was significantly greater than the maximum combinations under the 100 W.2. 100W: the Bla of 30×8 combination, 40×5 combination and 50×2 combination increased one by one, no significant difference existed between the 30×8 and40×5 combination(P > 0.05),but there was significant difference existed among30×8 and 50×2 combination, there was also difference existed among compositions 40×5 and 50×2(P <0.05).200W: the Bla of the three combinations increased one by one, difference existed among compositions; the minimum Bla combinations under the 200 W was significantly greater than the maximum combinations under the 100 W.3. 100W: the EE of the three compositions was increased and among groups were significant different(P <0.01); 200W: the EE of the three compositions also showed an increasing state, but 40×5 and 50×2 combinations are not statistically different(P> 0.05); the EE of 30×8 combination under the 200 W was significantly greater than the 50×2 combination under the 100W(P <0.01).Conclusion and suggestions:1. At a lower external power, the high-frequency low-impedance ergometer combination have a higher cardiorespiratory response and energy expenditure level. The 30×8 and 40×5 combinations mainly supplied by aerobic energy and they can work for a longer time, so they are suitable for aerobic endurance training, fitness exercise and fat loss rowing;2. At a higher external power, the high-frequency low-impedance ergometer combination also have a higher cardiorespiratory response and energy expenditure level. The 40×5 and 50×2 combinations may be near or achieve the intensity of the maximum oxygen uptake. Rowers at a lower level can do the high-intensity interval training according the intensity to improve the ability of aerobic endurance;3. Each combination of higher external power have a higher cardiorespiratory response and energy expenditure level than the combinations in the lower external power. The rowers at a lower level can use the combinations to do the ergometer training. |
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