Sawicka A K, Jaworska J, Brzeska B, Sabisz A, Samborowska E, Radkiewicz M, Szurowska E, Winklewski P J, Szarmach A, Olek R A
Robert A. Olek, Department of Athletics, Strength, and Conditioning, Poznan University of Physical Education, Krolowej Jadwigi 27/39; 61-871 Poznan, Poland, e-mail:
J Nutr Health Aging. 2022;26(10):945-953. doi: 10.1007/s12603-022-1848-y.
To evaluate the effect of L-carnitine (LC) in combination with leucine supplementation on muscle strength and muscle hypertrophy in aged women participating in a resistance exercise training (RET) program.
DESIGN/SETTING/PARTICIPANTS: Thirty-seven out of sixty (38.3% dropout) healthy women aged 60-75 years (mean 67.6 ± 0.7 years) completed the intervention in one of three groups. One of the supplemented groups received 1 g of L-carnitine-L-tartrate in combination with 3 g of L-leucine per day (LC+L group; n = 12), and the second supplemented group received 4 g of L-leucine per day (L group; n = 13). The control group (CON group; n = 12) received no supplementation.
All three groups completed the same RET protocol involving exercise sessions twice per week for 24 weeks.
Before and after the experiment, participants performed isometric and isokinetic muscle strength testing on the Biodex dynamometer. The cross-sectional areas of the major knee extensors and total thigh muscles were assessed using magnetic resonance imaging. Fasting serum levels of insulin-like growth factor-1 (IGF-1), myostatin and decorin, and plasma levels of total carnitine (TC) and trimethylamine-N-oxide (TMAO) levels were measured.
The 24-week RET significantly increased muscle strength and muscle volume, but the group and time interactions were not significant for the muscle variables analyzed. Plasma total carnitine increased only in the LC+L group (p = 0.009). LC supplementation also caused a significant increase in plasma TMAO, which was higher after the intervention in the LC+L group than in the L (p < 0.001), and CON (p = 0.005) groups. The intervention did not change plasma TMAO concentration in the L (p = 0.959) and CON (p = 0.866) groups. After the intervention serum decorin level was higher than before in both supplemented groups combined (p = 0.012), still not significantly different to post intervention CON (p = 0.231). No changes in serum IGF-1 and myostatin concentrations and no links between the changes in blood markers and muscle function or muscle volume were observed.
LC combined with leucine or leucine alone does not appear to improve the effectiveness of RET.
评估左旋肉碱（LC）联合补充亮氨酸对参与抗阻运动训练（RET）计划的老年女性肌肉力量和肌肉肥大的影响。
设计/地点/参与者：60名年龄在60 - 75岁（平均67.6±0.7岁）的健康女性中，有37名（38.3%退出）完成了三个组之一的干预。其中一个补充组每天接受1克酒石酸左旋肉碱与3克L - 亮氨酸（LC + L组；n = 12），第二个补充组每天接受4克L - 亮氨酸（L组；n = 13）。对照组（CON组；n = 12）不接受补充。
所有三组都完成了相同的RET方案，包括每周两次锻炼，共24周。
在实验前后，参与者在Biodex测力计上进行等长和等速肌肉力量测试。使用磁共振成像评估主要膝关节伸肌和大腿总肌肉的横截面积。测量空腹血清胰岛素样生长因子-1（IGF - 1）、肌肉生长抑制素和核心蛋白聚糖水平，以及血浆总肉碱（TC）和三甲胺-N-氧化物（TMAO）水平。
24周的RET显著增加了肌肉力量和肌肉体积，但所分析的肌肉变量的组间和时间交互作用不显著。血浆总肉碱仅在LC + L组中增加（p = 0.009）。补充LC还导致血浆TMAO显著增加，干预后LC + L组的TMAO高于L组（p < 0.001）和CON组（p = 0.005）。干预在L组（p = 0.959）和CON组（p = 0.866）中未改变血浆TMAO浓度。干预后，两个补充组联合的血清核心蛋白聚糖水平高于干预前（p = 0.012），但与干预后CON组仍无显著差异（p = 0.231）。未观察到血清IGF - 1和肌肉生长抑制素浓度变化，以及血液标志物变化与肌肉功能或肌肉体积之间的联系。
LC联合亮氨酸或单独使用亮氨酸似乎并不能提高RET的有效性。
