Lay B S, Sparrow W A, O'Dwyer N J
School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Vic., Australia.
Hum Mov Sci. 2005 Oct-Dec;24(5-6):833-48. doi: 10.1016/j.humov.2005.10.009. Epub 2005 Dec 5.
Kinematic (relative phase error), metabolic (oxygen consumption, heart rate) and attentional (baseline and cycling reaction times) variables were measured while participants practised a high energy-demanding, intrinsically unstable 90 degrees relative phase coordination pattern on independent bicycle ergometers. The variables were found to be strongly inter-correlated, suggesting a link between emerging performance stability with practice and minimal metabolic and attentional cost. The effects of practice of 90 degrees relative phase coordination on the performance of in-phase (0 degrees-phase) and antiphase (180 degrees-phase) coordination were investigated by measuring the relative phase attractor layouts and recording the metabolic and attentional cost of the three coordination patterns before and after practice. The attentional variables did not differ significantly between coordination patterns and did not change with practice. Before practice, the coordination performance was most accurate and stable for in-phase cycling, with antiphase next and 90 degrees-phase the poorest. However, metabolic cost was lower for antiphase than either in-phase or 90 degrees-phase cycling, and the pre-practice attractor layout deviated from that predicted on the basis of dynamic stability as an attractor state, revealing an attraction to antiphase cycling. After practice of 90 degrees-phase cycling, in-phase cycling remained the most accurate and stable, with 90 degrees-phase next and antiphase the poorest, but antiphase retained the lowest metabolic energy cost. The attractor layout had changed, with new attractors formed at the practised 90 degrees-phase pattern and its symmetrical partner of 270 degrees-phase. Considering both the pre- and post-practice results, attractors were formed at either a low metabolic energy cost but less stable (antiphase) pattern or at a more stable but higher metabolic energy cost (90 degrees-phase) pattern, but in neither case at the most stable and accurate (in-phase) pattern. The results suggest that energetic factors affect coordination dynamics and that coordination modes lower in metabolic energy expenditure may compete with dynamically stable modes.
在参与者于独立自行车测力计上练习一种高能量需求、本质上不稳定的90度相对相位协调模式时，对运动学（相对相位误差）、代谢（耗氧量、心率）和注意力（基线和骑行反应时间）变量进行了测量。发现这些变量之间存在很强的相互关联，这表明随着练习出现的表现稳定性与最低代谢和注意力成本之间存在联系。通过测量相对相位吸引子布局，并记录练习前后三种协调模式的代谢和注意力成本，研究了90度相对相位协调练习对同相（0度相位）和反相（180度相位）协调表现的影响。注意力变量在协调模式之间没有显著差异，并且不会随着练习而改变。在练习前，同相骑行的协调表现最准确和稳定，其次是反相，90度相位最差。然而，反相的代谢成本低于同相或90度相位骑行，并且练习前的吸引子布局偏离了基于动态稳定性预测的吸引子状态，显示出对反相骑行的吸引力。在90度相位骑行练习后，同相骑行仍然最准确和稳定，其次是90度相位，反相最差，但反相保持了最低的代谢能量成本。吸引子布局发生了变化，在练习的90度相位模式及其270度相位的对称模式处形成了新的吸引子。综合练习前后的结果，吸引子形成于代谢能量成本低但稳定性较差（反相）的模式，或者形成于稳定性较高但代谢能量成本较高（90度相位）的模式，但在这两种情况下都不是最稳定和准确（同相）的模式。结果表明，能量因素影响协调动力学，并且代谢能量消耗较低的协调模式可能与动态稳定模式相互竞争。
