Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain.
Department of Sports Sciences and Physical Conditioning, Faculty of Education, Universidad Católica de la Santísima Concepción, Concepción, Chile.
J Strength Cond Res. 2023 Jul 1;37(7):1367-1374. doi: 10.1519/JSC.0000000000004405. Epub 2023 Jan 18.
Miras-Moreno, S, García-Ramos, A, Jukic, I, and Pérez-Castilla, A. Two-point method applied in field conditions: a feasible approach to assess the load-velocity relationship variables during the bench pull exercise. J Strength Cond Res 37(7): 1367-1374, 2023-This study explored the between-session reliability and concurrent validity of the load-velocity (L-V) relationship variables obtained from different methods during the Smith machine bench pull exercise. In a counterbalanced order, 23 resistance-trained male subjects performed 2 sessions against 6 different loads in one week and 2 sessions against the lightest and heaviest loads in another week. The L-V relationship variables (load-axis intercept [ L0 ], velocity-axis intercept [ v0 ], and area under the L-V relationship line [ Aline ]) were obtained using the mean and peak velocity by the standard multiple-point (all 6 loads were used for the L-V modeling), modified multiple-point (the data point that most reduced the coefficient of determination was omitted from the L-V modeling), and 2-point (only 2 loads were used for the L-V modeling) methods. The reliability of the L-V relationship variables was acceptable for all methods (within-subjects coefficient of variation [CV] = 2.09-9.21%). The standard multiple-point and 2-point methods provided greater reliability for all L-V relationship variables compared with the modified multiple-point method (CV ratio ≥ 1.27), while the 2-point method provided similar (CV ratio = 1.04 for Aline ) or greater (CV ratio = 1.50 for L0 and 1.62 for v0 ) reliability than the standard multiple-point method. The concurrent validity of the modified multiple-point and 2-point methods was acceptable for the L-V relationship variables (effect size ≤ 0.62; r ≥ 0.76). These results suggest that the 2-point method is not only a valid procedure but also more reliable, simpler, faster, and less prone to fatigue than multiple-point methods for assessing maximal neuromuscular capacities through the L-V relationship.
米拉-莫雷诺、加西亚-拉莫斯、尤基奇和佩雷斯-卡斯蒂利亚研究了在史密斯机卧推运动中，不同方法获得的负荷-速度（L-V）关系变量的组内重复性和同时效度。23 名受过抗阻训练的男性受试者在一周内以平衡顺序完成了 2 次试验，共 6 个不同的负荷，另一周完成了 2 次试验，分别对抗轻和重的负荷。使用标准多点法（所有 6 个负荷都用于 L-V 建模）、改良多点法（从 L-V 建模中排除最能降低决定系数的数据点）和 2 点法（仅使用 2 个负荷进行 L-V 建模），获得 L-V 关系变量（负荷轴截距 [L0]、速度轴截距 [v0]和 L-V 关系线下面积 [Aline]）。所有方法的 L-V 关系变量的可靠性均为可接受（组内变异系数 [CV] = 2.09-9.21%）。与改良多点法相比（CV 比值≥1.27），标准多点法和 2 点法为所有 L-V 关系变量提供了更高的可靠性，而 2 点法则为 Aline 提供了相似（CV 比值=1.04）或更高（L0 的 CV 比值=1.50，v0 的 CV 比值=1.62）的可靠性。改良多点法和 2 点法的同时效度对于 L-V 关系变量是可接受的（效应大小≤0.62；r≥0.76）。这些结果表明，2 点法不仅是一种有效的程序，而且与多点法相比，评估最大神经肌肉能力的 L-V 关系时，2 点法更可靠、更简单、更快且不易疲劳。
