Bell Kirsten E, Brook Matthew S, Snijders Tim, Kumbhare Dinesh, Parise Gianni, Smith Ken, Atherton Philip J, Phillips Stuart M
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
Front Nutr. 2019 Apr 11;6:40. doi: 10.3389/fnut.2019.00040. eCollection 2019.
We previously showed that daily consumption of a multi-ingredient nutritional supplement increased lean mass in older men, but did not enhance lean tissue gains during a high-intensity interval training (HIIT) plus resistance exercise training (RET) program. Here, we aimed to determine whether these divergent observations aligned with the myofibrillar protein synthesis (MyoPS) response to acute unaccustomed and accustomed resistance exercise. A sub-sample of our participants were randomly allocated ( = 15; age: 72 ± 7 years; BMI: 26.9 ± 3.1 kg/m [mean ± SD]) to ingest an experimental supplement (SUPP, = 8: containing whey protein, creatine, vitamin D, and n-3 PUFA) or control beverage (CON, = 7: 22 g maltodextrin) twice per day for 21 weeks. After 7 weeks of consuming the beverage alone (Phase 1: SUPP/CON only), subjects completed 12 weeks of RET (twice per week) + HIIT (once per week) (Phase 2: SUPP/CON + EX). Orally administered deuterated water was used to measure integrated rates of MyoPS over 48 h following a single session of resistance exercise pre- (unaccustomed) and post-training (accustomed). Following an acute bout of accustomed resistance exercise, 0-24 h MyoPS was 30% higher than rest in the SUPP group (effect size: 0.86); however, in the CON group, 0-24 h MyoPS was 0% higher than rest (effect size: 0.04). Nonetheless, no within or between group changes in MyoPS were statistically significant. When collapsed across group, rates of MyoPS in recovery from acute unaccustomed resistance exercise were positively correlated with training-induced gains in whole body lean mass ( = 0.63, = 0.01). There were no significant between-group differences in MyoPS pre- or post-training. Integrated rates of MyoPS post-acute exercise in the untrained state were positively correlated with training-induced gains in whole body lean mass. Our finding that supplementation did not alter 0-48 h MyoPS following 12 weeks of training suggests a possible adaptive response to longer-term increased protein intake and warrants further investigation. This study was registered at ClinicalTrials.gov. www.ClinicalTrials.gov, identifier: NCT02281331.
我们之前的研究表明，每日食用一种多成分营养补充剂可增加老年男性的瘦体重，但在高强度间歇训练（HIIT）加抗阻运动训练（RET）计划期间，并未增强瘦组织的增加。在此，我们旨在确定这些不同的观察结果是否与肌原纤维蛋白合成（MyoPS）对急性不习惯和习惯抗阻运动的反应一致。我们的参与者子样本被随机分配（n = 15；年龄：72±7岁；体重指数：26.9±3.1 kg/m²[平均值±标准差]），每天两次摄入实验性补充剂（SUPP，n = 8：含乳清蛋白、肌酸、维生素D和n-3多不饱和脂肪酸）或对照饮料（CON，n = 7：22 g麦芽糊精），持续21周。在仅饮用饮料7周后（第1阶段：仅SUPP/CON），受试者完成12周的RET（每周两次）+ HIIT（每周一次）（第2阶段：SUPP/CON + EX）。口服氘代水用于测量在单次抗阻运动前（不习惯）和训练后（习惯）48小时内MyoPS的综合速率。在一次习惯抗阻运动急性发作后，SUPP组0 - 24小时的MyoPS比休息时高30%（效应大小：0.86）；然而，在CON组中，0 - 24小时的MyoPS比休息时高0%（效应大小：0.04）。尽管如此，MyoPS在组内或组间的变化均无统计学意义。当合并各小组数据时，急性不习惯抗阻运动恢复过程中的MyoPS速率与训练诱导的全身瘦体重增加呈正相关（r = 0.63，P = 0.01）。训练前或训练后MyoPS在组间无显著差异。未训练状态下急性运动后MyoPS的综合速率与训练诱导的全身瘦体重增加呈正相关。我们的研究发现，补充剂在12周训练后并未改变0 - 48小时的MyoPS，这表明可能对长期增加的蛋白质摄入量有适应性反应，值得进一步研究。本研究已在ClinicalTrials.gov注册。网址：www.ClinicalTrials.gov，标识符：NCT02281331。
