Sprint Interval Training Attenuates Neuromuscular Function and Vagal Reactivity Compared With High-Intensity Functional Training in Real-World Circumstances

Abstract

Benítez-Flores, S, de S. Castro, FA, Lusa Cadore, E, and Astorino, TA. Sprint interval training attenuates neuromuscular function and vagal reactivity compared with high-intensity functional training in real-world circumstances. J Strength Cond Res 37(5): 1070-1078, 2023-The aim of this study was to compare the acute cardiovascular and neuromuscular effects of 3 time-matched sessions of high-intensity training. Eighteen moderately active adults (9 women and 9 men [age: 23 6 2.9 years; maximum oxygen consumption (V Ȯ2 max): 47.6 6 4.1 ml•kg 21 •min 21 ]) performed three low-volume (;9 minutes) sessions in a randomized order: sprint interval training (SIT), burpee interval training (BIT) (10 3 5 seconds efforts 3 35 seconds recovery), and vigorous intensity continuous training (VICT) (6 minutes 5 seconds of running at ;85% of peak heart rate [HR peak ]). Indices related to heart rate (HR), neuromuscular performance (counter movement jump height [CMJ height ] and squat and bench press power), and autonomic balance (heart rate recovery and heart rate variability [HRR and HRV] )were monitored during exercise. Sprint interval training and VICT elicited a higher HR mean (171.3 6 8.4 and 166.5 6 7.5 vs. 150.5 6 13.6 b•min 21 , p , 0.001) and time of $90%HR peak (133.3 6 117.4 and 110 6 128.9 vs. 10 6 42.4 seconds, p , 0.01) than BIT. Sprint interval training exhibited a slower HRR and lower HRV than BIT and VICT (p , 0.05) postsession. Moreover, only SIT resulted in a significant decline (p , 0.01) in CMJ height (34.7 6 7.2 to 33.5 6 7.2 cm), relative squat mean power (25.5 6 4.5 to 23.8 6 4.9 W•kg 21 ), and relative bench press peak power (6.9 6 2.4 to 6.2 6 2.5 W•kg 21 ). Results revealed that SIT diminishes the sympathovagal reactivation and neuromuscular performance compared with work-matched BIT and VICT.

Extremely Low-Volume Burpee Interval Training Equivalent to 8 Minutes Per Session Improves Vertical Jump Compared with Sprint Interval Training in Real-World Circumstances

“…The findings corroborate those in a recent metaanalysis in which HIFT was found to attenuate increases in cardiorespiratory fitness than traditional aerobic exercise (39). These outcomes may be associated with the lower %HR peak for BIT than for SIT observed in this study (Table 2) and a prior study (3). In addition, prior work shows peripheral adaptations in skeletal muscle related to the improved mitochondrial function, such as increased citrate synthase, cytochrome c oxidase subunit IV, and succinate dehydrogenase after 2 weeks of SIT (40).…”

“…Exercise training included 5 sessions for each group, composed of 10 “all-out” bouts of 4-second duration with 30 seconds of recovery. This protocol was used in a previous acute study (3) and was included in a meta-analysis showing significant aerobic and anaerobic adaptations in response to SIT (6). The training intensity was monitored during each session using physiological and psychological outcomes.…”

“…Nevertheless, to our knowledge, no study has compared chronic responses between HIFT vs. SIT, and only 2 studies compared the acute response to each regimen (3,14). In addition, the effects of HIFT, including short "all-out" bouts on cardiorespiratory fitness and neuromuscular performance, have yet to be explored.…”