Abstract
Creatine dilution (D 3-cr) is a technique for estimating total skeletal muscle mass (SMM) with practical utility, but has not been applied in athletic populations where body composition may differ to that in the normal population. This study aimed to assess the agreement between SMM derived from both D 3-cr and that obtained from whole-body magnetic resonance imaging (MRI) in 15 male and 5 female national level kayakers (stature: 182.0 ± 13.1 and 170.0 ± 9.0 cm; body mass: 80.6 ± 9.9 and 66.4 ± 6.0 kg; V̇O 2peak: 56.5 ± 7.0 and 49.6 ± 4.4 mL kg −1 min −1, mean ± SD). SMM was determined following 60 mg of dosed D 3-cr and analysis of expelled urine collected on four subsequent days for creatine, creatinine, D 3-cr, and D 3-creatinine using liquid chromatography/mass spectroscopy. SMM was then estimated by assuming a creatine pool size of 4.3 g/kg. During the same time period, a whole-body MRI was undertaken to derive SMM from the analysis of multiple slices taken across the body. A strong positive correlation (F = 74.32; R = 0.90; P <.0001) between the two methods was observed, but the D 3-cr SMM was found to be significantly higher (43.3 ± 6.8 kg) when compared with MRI (36.3 ± 5.8 kg, P <.0001). However, the difference between the methods was removed when a higher intramuscular creatine pool (5.1 g/kg) was assumed. These data show that D 3-cr has potential utility in athletes, as referenced against MRI, but show that assumptions regarding creatine pool size need to be carefully considered.
Original language | English |
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Journal | Scandinavian Journal of Medicine and Science in Sports |
Early online date | 12 Nov 2019 |
DOIs | |
Publication status | E-pub ahead of print - 12 Nov 2019 |
Keywords
- MRI
- body composition
- creatinine
- deuterium labeling
- isotope labeling