Author(s): MARCHELEK-MYSLIWIEC, M., NOWACZYK, P., PODGÓRSKI, T., DURKALEC-MICHALSKI, K., Institution: POMERANIAN MEDICAL UNIVERSITY, Country: POLAND, Abstract-ID: 1876

INTRODUCTION:
Beta‐hydroxy‐beta‐methylbutyrate (HMB) is supposed to facilitate protein synthesis and thus support nutritional status, physical capacity and exercise performance. Still data on the effects of HMB ingestion combined with high-intensity functional training (HIFT) stimuli on aerobic capacity and fitness are scarce and inconclusive, especially in healthy untrained individuals. We hypothesized that 3-wk HMB supplementation (90 mgHMB/kg Fat-free mass[FFM]) will result in the improvement in aerobic capacity and selected blood biomarkers, and the magnitude of these changes will be amplified by HIFT stimuli.
METHODS:
The randomized triple-blind placebo(PLA)-controlled parallel study was conducted in 32 untrained males, allocated into the HMB (n=16; 32±7 years, 66.3±9.2 kg FFM) or the PLA (n=16; 34±8 years, 69.5±11.8 kg FFM) group. The study protocol included two 3-wk periods: 1) supplementation (SUP) with HMB/PLA and 2) SUP+EX – ingestion of HMB/PLA and implementing two HIFT units/wk. Testing visits were performed at baseline (TBAS), after the SUP (TSUP), and the SUP+EX (TSUP+EX) periods. The incremental cycling test (ICT) was performed. Oxygen uptake (VO2), carbon dioxide exhalation and heart rate (HR) were recorded. The following indices were evaluated: time to exhaustion, maximal VO2, maximal power (PMAX), and maximal HR, as well as times to anaerobic threshold (TAT), respiratory compensation point (TRCP), and corresponding AT/RCP values: VO2AT/RCP, PAT/RCP, HRAT/RCP. Blood samples were taken at rest and after the ICT for evaluation of creatine kinase and lactate dehydrogenase activity, and cortisol and free/total testosterone concentrations (only at REST). Mixed model of RM ANOVA was applied – the interaction of time (TBAS, TSUP, TSUP+EX) x treatment (HMB/PLA) was analyzed.
RESULTS:
There were significant time x treatment interactions for TAT (p=0.037), PAT (in W; (p=0.037), TRCP (p<0.001), and PRCP (in W: p<0.001 and in W/kg: p=0.006). In the HMB group TAT and PAT were higher at TSUP+EX vs. TBAS (TAT: p<0.001; PAT: p<0.001) and TSUP (TAT: p=0.041; PAT: p=0.032), still no differences within the PLA group were observed. In the HMB group TRCP and absolute PRCP (in W) were higher at TSUP vs. TBAS (TRCP: p=0.022; PRCP: p=0.025); TSUP+EX vs. TSUP (TRCP: p=0.002; PRCP: p=0.005); and TSUP+EX vs. TBAS (TRCP: p<0.001; PRCP: p<0.001), still no differences within the PLA group were observed. In the HMB group relative PRCP (in W/kg) was higher at TSUP+EX vs. TBAS (p<0.001), still no differences within the PLA group were observed. There were no significant time x treatment interactions for any of the evaluated blood variables.
CONCLUSION:
HMB ingestion effectively supports aerobic fitness and capacity in untrained males, and the degree of changes seem to be strengthen after introducing HIFT stimuli. AT and RCP indices tend to improve more readily. The implemented treatment had no effect on hormones or muscle damage/fatigue indices.