Faculté de médecine, Division de kinésiologie, Département de médecine sociale et préventive, Université Laval, Québec, Canada.
Int J Obes (Lond). 2010 May;34(5):936-42. doi: 10.1038/ijo.2009.300. Epub 2010 Jan 26.
Overweight individuals sway more than normal weight individuals. Major weight loss improves their balance control despite a related decrease in muscle strength. Presumably, muscular strength is an important factor for balance control. This study investigated the effect that a change in body mass has on relative strength and balance control.
Force (isometric knee extension) and balance control (center of pressure speed and range) were studied in three groups; normal weight (BMI <25 kg m(-2)), obese (30 kg m(-2) <BMI< 40 kg m(-2)) and excess obese (BMI >40 kg m(-2)) Caucasian male individuals.
The excess obese individuals who underwent bariatric surgery as a weight loss strategy were studied before, 3 and 12 months after losing on average, 66.9 kg (+/-95% CI 55.8, 77.9 kg; on average, 45% of their weight). The obese individuals who underwent diet modifications were studied before dieting and when resistance to weight loss occurred after losing on average 11.7 kg (+/-95% CI 9.3, 14.2 kg; on average, 12% of their weight). The control group was studied twice, 50 weeks apart. In obese and excess obese individuals, losing weight reduced absolute knee muscular strength on average, by 8.2 kg (+/-95% CI 3.9, 12.5 kg; on average, 10% of their strength) and 23.9 kg (+/-95% CI 12.1, 35.8 kg; on average, 33% of their strength). However, it also increased balance control measured with speed of the center of foot pressure, on average, by 0.10 cm s(-1) (+/-95% CI 0.05, 0.14 cm s(-1); or increased of 12%) and 0.28 cm s(-1) (+/-95% CI 0.07, 0.47 cm s(-1); increased of 27%), respectively. Relative strength increased approximately by 22% for only the excess obese group 12 months post surgery.
This suggests, in overweight individuals, weight loss is more efficient at improving balance control than increasing, or even maintaining muscle strength. In these individuals, training programs aimed at improving balance control should primarily target weight loss.
超重个体比正常体重个体更易摇晃。尽管体重下降会导致肌肉力量相应减弱，但体重的大幅减轻仍有助于改善平衡控制能力。据推测，肌肉力量是平衡控制的一个重要因素。本研究旨在探讨体重变化对相对力量和平衡控制的影响。
本研究共纳入三组人群：正常体重者（BMI<25kg/m²）、肥胖者（30kg/m²<BMI<40kg/m²）和超肥胖者（BMI>40kg/m²）。所有受试者均为白种男性，我们分别于他们接受减重手术（作为一种减重策略）前后 3 个月及 12 个月，以及节食（作为一种减重策略）前后测量其等长膝关节伸肌力量（力）和平衡控制能力（中心压力速度和范围）。
接受减重手术的超肥胖个体在平均减重 66.9kg（95%可信区间 55.8, 77.9kg；平均为体重的 45%）后，分别于术前、术后 3 个月及 12 个月接受了本研究。接受节食的肥胖个体在平均减重 11.7kg（95%可信区间 9.3, 14.2kg；平均为体重的 12%）及体重减轻出现抵抗后进行了本研究。对照组在 50 周内进行了两次研究。在肥胖者和超肥胖者中，体重减轻平均导致绝对膝关节肌肉力量下降 8.2kg（95%可信区间 3.9, 12.5kg；平均为力量的 10%）和 23.9kg（95%可信区间 12.1, 35.8kg；平均为力量的 33%）。然而，体重减轻还平均使足底中心压力速度分别增加 0.10cm/s（95%可信区间 0.05, 0.14cm/s；增加 12%）和 0.28cm/s（95%可信区间 0.07, 0.47cm/s；增加 27%），从而改善了平衡控制能力。仅超肥胖组在术后 12 个月时相对力量增加约 22%。
这表明，在超重个体中，体重减轻在改善平衡控制能力方面比增加肌肉力量甚至维持肌肉力量更有效。在这些个体中，旨在改善平衡控制能力的训练计划应主要针对体重减轻。
