Gadeberg P, Andersen H, Jakobsen J
Department of Neurology and Magnetic Resonance Research Center, Aarhus University Hospital, 8000 Aarhus C, Denmark.
J Appl Physiol (1985). 1999 May;86(5):1670-5. doi: 10.1152/jappl.1999.86.5.1670.
The validity of the methods used for determination of muscle mass has not been evaluated previously. We determined muscle mass by estimating muscle volume with assumption-free stereological techniques applied to magnetic resonance imaging (MRI) in 18 healthy untrained subjects (6 women, 12 men) aged 41 yr (29-64 yr; median, range). Muscle mass was also estimated by measuring leg circumference and cross-sectional muscle areas (CSA) from MRIs at three predetermined levels. Power [peak torque (PT)] of the ankle dorsiflexors and plantar flexors was estimated by using isokinetic dynamometry. Dorsiflexor volume (r2 = 0.76, P < 5 x 10(-6)) and CSA (r2 = 0.73, P < 5 x 10(-5)) were related to PT, whereas circumference was not (r2 = 0.17, not significant). Correspondingly, a relationship to plantar PT was established for plantar flexor volume (r2 = 0.69, P < 5 x 10(-5)) and CSA (r2 = 0.46, P < 5 x 10(-3)) but not leg circumference (r2 = 0.15, not significant). SDs of the residuals were smaller for the relationship between dorsiflexor PT and volume than between PT and CSA (0.42 vs. 0.45) for plantar flexors (1.5 vs. 2.0). By using the Cavalieri method, six MRI sections and 15 min of point counting are sufficient to obtain a valid estimate of the volume of the muscles of the lower leg.
此前尚未评估过用于测定肌肉量的方法的有效性。我们采用无假设的体视学技术对磁共振成像（MRI）进行分析，以此估计肌肉体积，从而测定了18名年龄为41岁（29 - 64岁；中位数，范围）的健康未受过训练的受试者（6名女性，12名男性）的肌肉量。还通过测量腿部周长以及在三个预定水平的MRI横截面肌肉面积（CSA）来估计肌肉量。使用等速测力法估计踝背屈肌和跖屈肌的力量[峰值扭矩（PT）]。背屈肌体积（r2 = 0.76，P < 5×10⁻⁶）和CSA（r2 = 0.73，P < 5×10⁻⁵）与PT相关，而周长则不然（r2 = 0.17，无显著性）。相应地，对于跖屈肌体积（r2 = 0.69，P < 5×10⁻⁵）和CSA（r2 = 0.46，P < 5×10⁻³）与跖屈PT建立了关系，但腿部周长未建立关系（r2 = 0.15，无显著性）。对于背屈肌PT与体积之间的关系，残差的标准差小于PT与CSA之间的标准差（0.42对0.45），对于跖屈肌则为（1.5对2.0）。通过使用卡瓦列里方法，六个MRI切片和15分钟的点计数足以获得小腿肌肉体积的有效估计值。
