ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2020 April;60(4):510-9

DOI: 10.23736/S0022-4707.19.10277-0

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English

Neuromuscular, hormonal and cardiovascular adaptations to eight-week HIIT and continuous aerobic training combined with neuromuscular electrical stimulation

Gökhan UMUTLU ¹ ✉, Nevzat DEMİRCİ ², Ayhan T. ERDOĞAN ¹, Nasuh E. ACAR ², Şenay B. FİDANCI ³

¹ School of Physical Education and Sports, Final International University, Kyrenia, Cyprus; ² School of Physical Education and Sports, Mersin University, Mersin, Turkey; ³ School of Medicine, Department of Medical Chemistry, Mersin University, Mersin, Turkey

BACKGROUND: Whether high-or-low intensity exercise coupled with neuromuscular electrostimulation (NMES) affect IGF-1 and IGFBP-1 is unknown. The scope of this study was to test whether 8-week high-intensity interval training (HIIT) and continuous aerobic training (CA) combined with/without NMES performed at 65% and 120% of VO2max on a cycle ergometer induce different metabolic adaptations.
METHODS: A randomized controlled trial with a parallel groups study design was used. Thirty healthy untrained male participants (age: 21.33±1.24 years, height: 177.80±5.97 cm, weight: 73.74±7.90 kg, lean body mass: 64.29±5.11 kg, percent body fat: 12.43±5.34%) voluntarily participated in this study. Six participants were allocated to Control, six to HIIT, six to HIIT+NMES, six to CA, and six to CA+NMES.
RESULTS: Pre- to post-test IVO2max, blood lactate concentrations, O2 kinetics, peak torques at 60o/s and 180o/s were found statistically significant (P<0.05, P<0.001). IGF-1 pre 15 min in CA and IGF-1 post 30 min in HIIT group was found significantly higher compared to control group (16.93±8.40 vs. 6.05±4.25, P=0.024; 10.80±3.94 vs. 6.15±2.56, P=0.037), respectively. Additionally, IGFBP-1 were found significantly higher in CA+NMES group than HIIT group (0.95±0.67 vs. 1.23±0.56). Eight week post IGF-1/IGFBP-1 ratios were found higher in pre 15 min, post 30 min and post 24 h compared to baseline pre 15 min, post 30 min and post 24 h measurements in all groups (8.92±4.72 vs. 3.93±3.14; 9.41±3.72 vs. 3.99±1.76; 8.63±3.01 vs. 5.89±3.01, respectively). Also, IGFBP-1 post 30 min was significantly lower in HIIT+NMES while CA group showed significantly lower baseline and 24 h post IGFBP-1 compared to pre-test measurements (Z=-3.20, P=0.001; Z=-3.72, P=0.000; Z=-2.93, P=0.000).
CONCLUSIONS: HIIT and CA training induce different stimuli on IGF-1 and IGFBP-1 and NMES application combined with high-and-low intensity exercise is highly effective in improving athletic performance.

KEY WORDS: Lactates; Cardiovascular system; Exercise test; Physiological adaptation; High-intensity interval training; Oxygen consumption