In:
Medicine & Science in Sports & Exercise, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. 1 ( 2019-1), p. 56-64
Abstract:
Leucine metabolites, α-hydroxyisocaproic acid (α-HICA) and β-hydroxy-β-methylbutyrate (calcium, HMB-Ca and free acid, HMB-FA), have been proposed to augment resistance training-induced changes in body composition and performance. Purpose We aimed to conduct a double-blind randomized controlled pragmatic trial to evaluate the effects of off-the-shelf leucine metabolite supplements of α-HICA, HMB-FA, and HMB-Ca on resistance training-induced changes in muscle thickness and performance. Methods Forty men were randomly assigned to receive α-HICA ( n = 10, fat-free mass [FFM] = 62.0 ± 7.1 kg), HMB-FA ( n = 11, FFM = 62.7 ± 10.5 kg), HMB-Ca ( n = 9, FFM = 65.6 ± 10.1 kg), or placebo (PLA; n = 10, FFM = 64.2 ± 5.7 kg). The training program consisted of whole body thrice weekly resistance training for 8 wk (seven exercises per session, three to four sets per session, at 70%–80% one repetition maximum). Skeletal muscle thickness by ultrasound, performance measures, and blood measures (creatine kinase, insulin-like growth factor 1, growth hormone, cortisol, and total testosterone) were evaluated at baseline and at the end of weeks 4 and 8. Results Time-dependent changes were observed for muscle thickness ( P 〈 0.001), one repetition maximum bench press and squat ( P 〈 0.001), Wingate peak power ( P = 0.02), countermovement jump height ( P = 0.03), power ( P = 0.006), creatine kinase, insulin-like growth factor-1, growth hormone, and cortisol (all P 〈 0.001). No significant between-group or time–group interactions were observed. Conclusions No leucine metabolite resulted in any ergogenic effects on any outcome variable. Supplementation with leucine metabolites—α-HICA, HMB-FA, or HMB-Ca—is not a supplementation strategy that improves muscle growth and strength development in young adult men.
Type of Medium:
Online Resource
ISSN:
1530-0315
,
0195-9131
DOI:
10.1249/MSS.0000000000001754
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2019
detail.hit.zdb_id:
2031167-9
SSG:
31
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