School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD, 4556, Australia.
School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, QLD, 4558, Australia.
Eur J Appl Physiol. 2018 Jun;118(6):1273-1286. doi: 10.1007/s00421-018-3861-8. Epub 2018 Apr 10.
High precision body composition assessment methods accurately monitor physique traits in athletes. The acute impact of subject presentation (ad libitum food and fluid intake plus physical activity) on body composition estimation using field and laboratory methods has been quantified, but the impact on interpretation of longitudinal change is unknown. This study evaluated the impact of athlete presentation (standardised versus non-standardised) on interpretation of change in physique traits over time. Thirty athletic males (31.2 ± 7.5 years; 182.2 ± 6.5 cm; 91.7 ± 10.3 kg; 27.6 ± 2.6 kg/m) underwent two testing sessions on 1 day including surface anthropometry, dual-energy X-ray absorptiometry (DXA), bioelectrical impedance spectroscopy (BIS) and air displacement plethysmography (via the BOD POD), with combinations of these used to establish three-compartment (3C) and four-compartment (4C) models.
Tests were conducted after an overnight fast (BASEam) and ~ 7 h later after ad libitum food/fluid and physical activity (BASEpm). This procedure was repeated 6 months later (POSTam and POSTpm). Magnitude of changes in the mean was assessed by standardisation.
After 6 months of self-selected training and diet, standardised presentation testing (BASEam to POSTam) identified trivial changes from the smallest worthwhile effect (SWE) in fat-free mass (FFM) and fat mass (FM) for all methods except for BIS (FM) where there was a large change (7.2%) from the SWE. Non-standardised follow-up testing (BASEam to POSTpm) showed trivial changes from the SWE except for small changes in FFM (BOD POD) of 1.1%, and in FM (3C and 4C models) of 6.4 and 3.5%. Large changes from the SWE were found in FFM (BIS, 3C and 4C models) of 2.2, 1.8 and 1.8% and in FM (BIS) of 6.4%. Non-standardised presentation testing (BASEpm to POSTpm) identified trivial changes from the SWE in FFM except for BIS which was small (1.1%). A moderate change from the SWE was found for BOD POD (3.3%) and large for BIS (9.4%) in FM estimations.
Changes in body composition utilising non-standardised presentation were more substantial and often in the opposite direction to those identified using standardised presentation, causing misinterpretation of change in physique traits. Standardised presentation prior to body composition assessment for athletic populations should be advocated to enhance interpretation of true change.
高精度的人体成分评估方法可以准确监测运动员的体质特征。已经量化了使用现场和实验室方法时，受测者呈现（随意摄入食物和液体以及进行体育活动）对人体成分估计的急性影响，但对解释纵向变化的影响尚不清楚。本研究评估了运动员呈现（标准化与非标准化）对随时间变化的体质特征解释的影响。30 名男性运动员（31.2±7.5 岁；182.2±6.5cm；91.7±10.3kg；27.6±2.6kg/m2）在 1 天内进行了两次测试，包括体表人体测量、双能 X 射线吸收法（DXA）、生物电阻抗谱法（BIS）和空气置换体描记法（通过 BOD POD），使用这些方法的组合来建立三腔（3C）和四腔（4C）模型。
在隔夜禁食（BASEam）后和大约 7 小时后（在随意摄入食物/液体和体育活动后）进行测试（BASEpm）。6 个月后（POSTam 和 POSTpm）重复该程序。通过标准化评估平均变化幅度。
在 6 个月的自我选择训练和饮食后，除了 BIS（FM）有较大变化（7.2%）来自于最小有意义变化（SWE）外，所有方法的标准化呈现测试（BASEam 到 POSTam）都显示出脂肪量（FM）和去脂体重（FFM）的微小变化。非标准化的随访测试（BASEam 到 POSTpm）显示除了 BOD POD 的 FFM（1.1%）和 3C 和 4C 模型的 FM（6.4%和 3.5%）有小变化外，其他均为 SWE 中的微小变化。来自 SWE 的较大变化是在 FFM（BIS、3C 和 4C 模型）中发现的 2.2%、1.8%和 1.8%，在 FM（BIS）中发现的 6.4%。非标准化呈现测试（BASEpm 到 POSTpm）显示除了 BIS（1.1%）外，FFM 中 SWE 的微小变化。在 FM 估计中，BOD POD（3.3%）和 BIS（9.4%）出现中度变化，BIS 出现较大变化。
使用非标准化呈现的身体成分变化更大，且通常与使用标准化呈现时所确定的变化方向相反，从而导致对体质特征变化的错误解释。对于运动员人群，在进行身体成分评估之前，应提倡使用标准化呈现，以增强对真实变化的解释。
