AUTHOR=Tong Tomas K. , Zhang Haifeng , Shi Hongru , Liu Yang , Ai Jingwen , Nie Jinlei , Kong Zhaowei 

TITLE=Comparing Time Efficiency of Sprint vs. High-Intensity Interval Training in Reducing Abdominal Visceral Fat in Obese Young Women: A Randomized, Controlled Trial

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.01048

DOI=10.3389/fphys.2018.01048

ISSN=1664-042X

ABSTRACT=<p><bold>Introduction:</bold> High-intensity interval training (HIIT) is an emerging lifestyle intervention strategy for controlling obesity. HIIT consisted of brief all-out supramaximal sprint intervals was termed as sprint interval training (SIT). This study was designed to examine the time-efficient characteristics of SIT in reducing abdominal visceral fat.</p><p><bold>Methods:</bold> A randomized controlled trial was conducted to compare the specific adaptations of SIT (80 × 6 s all-out cycle sprints interspersed with 9 s passive recovery) with those resulting from a HIIT regimen with training volume relatively higher (repeated 4 min bouts of cycling at 90% <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2<italic>max</italic></sub> alternated with 3 min rest, until the work of 400KJ was achieved), and with those of nonexercising control counterparts (CON). Forty-six obese young women (body fat percentage ≥30) received either SIT (<italic>n</italic> = 16), HIIT (<italic>n</italic> = 16), or no training (<italic>n</italic> = 14), 3–4 sessions per week, for 12 weeks. The abdominal visceral fat area (AVFA) and abdominal subcutaneous fat area (ASFA) of the participants were measured through computed tomography scans pre-intervention and post-intervention. Total fat mass and the fat mass of the android, gynoid, and trunk regions were assessed through dual-energy X-ray absorptiometry.</p><p><bold>Results:</bold> Following the intervention, abdominal visceral and subcutaneous fat were reduced markedly (<italic>p</italic> &lt; 0.05). The reduction in AVFA (−6.31, −9.7 cm<sup>2</sup>) was not different between SIT and HIIT (<italic>p</italic> &gt; 0.05), while the reduction in ASFA (−17.4, −40.7 cm<sup>2</sup>) in SIT was less than that in HIIT (<italic>p</italic> &lt; 0.05). Less reduction in the fat mass of the trunk (−1.2, −2.0 kg) region was also found in SIT, while the reductions in fat percentage (−1.9%, −2.0%), total fat mass (−2.0, −2.8 kg), and fat mass of the android (−0.2, −0.2 kg), and gynoid (−0.4, −0.3 kg) regions did not differ between the two regimes (<italic>p</italic> &gt; 0.05). In contrast, the increase in <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2<italic>max</italic></sub> was significant greater following the SIT than HIIT (<italic>p</italic> &lt; 0.01). No variable changed in CON.</p><p><bold>Conclusion:</bold> Such findings suggest that the lower training load and exercise time commitments of the SIT regime could optimize the time-efficiency advantage of the traditional HIIT, facilitating the abdominal visceral fat reduction in obese young women.</p>