INTRODUCTIONThe primary aim of the current study was to determine the effect of two doses of chronic high-intensity interval training (HIT) on changes in maximal fat oxidation (MFO) and body ...composition.
METHODSSedentary women (N = 23, age and V˙O2max = 24.2 ± 6.2 yr and 30.3 ± 5.2 mL·kg·min, respectively) completed either high (HI) (80%–90% maximal workload) or moderate (MOD) intensity (60%–80% maximal workload) HIT on a cycle ergometer 3 d·wk for 12 wk consisting of 6–10 sixty-second bouts interspersed with active recovery. Seven women of similar age and fitness level served as controls. Every 3 wk, substrate oxidation was assessed during progressive exercise via indirect calorimetry to determine MFO and minimum fat oxidation, and body composition was assessed every 6 wk. Repeated-measures ANOVA was used to examine changes in substrate oxidation in response to training, with training group used as a between-subjects variable.
RESULTSResults revealed improved MFO (P = 0.04, 19%–25%) and minimum fat oxidation (P = 0.001, 22–24 W) in response to HIT, yet the magnitude of improvement was similar (P > 0.05) between training paradigms. No change (P > 0.05) in body weight, percent body fat, or waist–hip circumference was revealed with training.
CONCLUSIONThese data suggest that 12 wk of either moderate or more strenuous interval training similarly enhance fat oxidation in sedentary women but do not alter body weight or body composition.
Although maximal oxygen uptake (VO
max) has been measured for almost 100 years, it is unknown when 'true' VO
max is attained. Primary (the VO
plateau) and secondary criteria are used to confirm VO
...max incidence, but frequency of the VO
plateau varies, and secondary criteria are relatively invalid. The verification test (VER) seems to elicit similar estimates of VO
max versus the incremental value (INC), yet existing data are limited by small populations and use of inadequate criteria to confirm 'true' VO
max. We investigated the efficacy of VER by analysing data from 109 participants who underwent INC followed by VER at 105% or 110% of peak power output (PPO). Differences in VO
max between VER and INC were analysed, and intraclass correlation coefficient (ICC), standard error of the mean (SEM) and minimum difference (MD) were computed. Results showed that VO
max was significantly higher (2%, P<0·05) in INC versus VER, VO
max was highly related between protocols (ICC = 0·99) and SEM and MD were low. However, 11% of participants did not reveal 'true' VO
max as the verification value was higher than INC by 3·0% - 3·3%. Fitness level altered the difference in VO
max between INC and VER in study one, as lower fitness individuals showed a larger difference in VO
max between protocols, although gender did not affect the difference in VO
max between protocols. Our data show that VER does not verify 'true' VO
max in all individuals, which may be related to their fitness level.
ABSTRACTMatthews, ARD, Astorino, TA, Crocker, GH, and Sheard, AC. Acute effects of high-intensity interval exercise while wearing a sauna suit on energy expenditure and excess post-exercise oxygen ...consumption. J Strength Cond Res XX(X)000–000, 2020—The use of sauna suits has increased because of claims that they enhance weight loss and increase body temperature during exercise. Therefore, the purpose of this study was to examine changes in energy expenditure (EE) and excess post-exercise oxygen consumption (EPOC) in response to high-intensity interval exercise (HIIE) while wearing a sauna suit. Twelve recreationally active men and women age = (28.7 ± 6.0 years) initially completed assessment of resting metabolic rate and maximal oxygen uptake. On two separate days, subjects completed HIIE consisting of ten 1-minute intervals at 85% peak power output, both with and without a sauna suit. Oxygen consumption, heart rate, and core temperature were continuously measured during and 1 hour after exercise. Energy expenditure during (285 ± 57 kcal vs. 271 ± 58 kcal) and post-exercise (123 ± 30 kcal vs. 113 ± 16 kcal) was significantly higher (p = 0.025) with a sauna suit than without a sauna suit. However, EPOC (6.19 ± 4.46 L of O2 vs. 4.25 ± 3.36 L of O2; p = 0.05) was not significantly different 1 hour after exercise, and core temperature was similar (p = 0.62) between conditions. Fat oxidation was significantly increased for 60 minutes after HIIE with a sauna suit (p = 0.009). Wearing a sauna suit during HIIE elicits greater EE vs. not wearing a sauna suit, but the increase of 23 kcal may not benefit weight loss.
•In-task affective valence is positive in the beginning of the low-volume high-intensity interval (LV-HIIE) session, but declines over the intervals.•Physical activity level and perceived exertion ...predict in-task affective valence to LV-HIIE in the beginning, middle, and end of the session.•Physical activity level and perceived exertion have a greater predictive role of in-task affective valence in the end of the LV-HIIE session.•Physically inactive adult males who report a high perceived exertion likely have a negative in-task affective response in the end of the LV-HIIE session.
Previous results reveal a decline in affective valence in response to progressive exercise in adults. However, this similar decline is not universally observed in response to high intensity interval exercise (HIIE), which may be due to its intermittent nature. The aim of the current study was to examine potential predictors of the in-task affective valence to low-volume HIIE (LV-HIIE; 10 × 60 s high-intensity intervals at 90% of maximal treadmill velocity interspersed by 60 s at 30% of maximal treadmill velocity). We analyzed data from 76 males (age and body mass index = 26.5 ± 4.4 yr and 27.3 ± 5.4 kg/m2) who had participated in previous investigations in our lab. Throughout each session, affective valence (Feeling Scale; + 5 to -5), rating of perceived exertion (RPE; Borg scale 6 to 20), and heart rate (HR) were measured. The predictors of in-task affective valence were analyzed during different phases of the LV-HIIE session (i.e. beginning, average of high-intensity intervals 1–3; middle, average of high-intensity intervals 4–7; and end, average of high-intensity intervals 8–10). Results showed a significant decline in affective valence (p < 0.001), increase in RPE (p < 0.001) and HR (p < 0.001) in response to LV-HIIE. Primary predictors of in-task affective valence to LV-HIIE were physical activity level and RPE (beginning, R2 = 0.511, p < 0.001; middle, R2 = 0.681, p < 0.001; end, R2 = 0.742, p = 0.008). In conclusion, physical activity level and perceived exertion significantly predict the in-task affective valence to LV-HIIE in adult males.
Pérez-Ifrán, P, Magallanes, CA, de S. Castro, FA, Astorino, TA, and Benítez-Flores, S. Extremely low-volume burpee interval training equivalent to 8 minutes per session improves vertical jump ...compared with sprint interval training in real-world circumstances. J Strength Cond Res 38(1): 10-20, 2024-The aim of this study was to compare the cardiometabolic and physical effects of 2 time-matched high-intensity programs in a real-world environment. Forty-three active and healthy adults (sex = 31 men and 12 women; age = 27 ± 5 years; peak heart rate HR peak = 190.7 ± 10.6 beat·min -1 ) were randomized to 2 very low-volume protocols (∼8 minutes): sprint interval training (SIT) ( n = 15), burpee interval training (BIT) ( n = 15), and control (CON) ( n = 13). Subjects in SIT and BIT performed 5 days of 10 × 4 second "all-out" efforts with 30 seconds of recovery. Body composition, blood pressure, countermovement jump (CMJ), 10-m sprint, shuttle run test (SRT), autonomic modulation , self-efficacy, and intention were evaluated before and after training. Sprint interval training elicited a higher %HR peak , energy expenditure, rating of perceived exertion category ratio 10 scale, and feeling scale than BIT ( p < 0.05). SRT distance was significantly improved in SIT ( p = 0.03, d = 0.62), whereas CMJ height was significantly enhanced in BIT ( p = 0.0014, d = 0.72). Self-efficacy progressively worsened for SIT than for BIT as sessions increased, and significant differences were found in 5× a week frequency between protocols ( p = 0.040, d = 0.79). No differences in intention to engage were detected between the regimens ( p > 0.05). No changes were observed in body composition, blood pressure, 10-m sprint, SRTV̇O 2max , or autonomic variables with training ( p > 0.05). Results exhibit that extremely low-volume SIT improved running performance, whereas BIT increased the vertical jump.
Abstract
Bogdanis, GC, Mallios, VJ, Katsikas, C, Fouseki, T, Holman, I, Smith, C, and Astorino, TA. Effects of exercise structure and modality on physiological and perceptual responses to exercise.
J ...Strength Cond Res
35(9): 2427–2432, 2021—This study examined the effect of exercise mode and intensity on physiological and perceptual responses to exercise. Twelve active adults (6 men and 6 women, age = 21.7 ± 1.6 years) initially performed incremental testing on the treadmill (TM) and cycle ergometer (CE) to assess maximal oxygen uptake (V̇
o
2
max) and ventilatory threshold (VT). During the next 4 visits in a randomized order, subjects performed 20 minutes of moderate-intensity continuous exercise (MICE) at an intensity 20% below VT on the TM (TM
MICE
) and cycle ergometer (CE
MICE
) as well as time-matched high-intensity interval exercise (HIIE; 10 1-minute bouts at workload equal to 20% above VT followed by 1-minute active recovery) on both modes (TM
HIIE
and CE
HIIE
). During exercise, gas exchange data, blood lactate concentration, and perceptual responses (rating of perceived exertion, affective valence, and enjoyment) were assessed. Heart rate (
p
< 0.001) and V̇
o
2
(
p
< 0.001) were higher in response to TM
HIIE
vs. CE
HIIE
as well as TM
MICE
vs. CE
MICE
. Blood lactate concentration was higher (
p
= 0.003) in response to CE
HIIE
vs. TM
HIIE
. The rating of perceived exertion was significantly higher (
p
< 0.001) in TM
MICE
compared with CE
MICE
which showed the most positive affective valence (
p
= 0.009). Enjoyment was similar across all bouts (
p
= 0.11). Treadmill-based HIIE leads to higher heart rate and V̇
o
2
vs. CE
HIIE
, although there was no difference in affective valence or enjoyment. Practitioners aiming to optimize the cardiorespiratory response to moderate or interval exercise in their clientele should recommend TM running rather than cycling.
Purpose
We determined the effects of two high-intensity interval training (HIIT) regimens the traditional (TRAD) and periodized (PER) on changes in maximal oxygen uptake (VO
2
max), body composition, ...and muscular strength in sedentary, obese women.
Methods
Seventeen women (age and BMI = 37.5 ± 10.5 year and 39.1 ± 4.3 kg/m
2
) were randomized into a 6 week regime of TRAD or PER which consisted of three sessions per week, two in the laboratory, and one on their own. Pre- and post-training, VO
2
max, body composition, and muscular strength of the knee extensors (KE) and flexors (KF) were assessed via ramp cycling to exhaustion, air displacement plethysmography, and isokinetic dynamometry, respectively.
Results
VO
2
max was increased by 4–5% in response to training (
p
= 0.045) with no group-by-time interaction (
p
= 0.79). Body mass, fat mass, and waist-to-hip ratio were unaltered (
p
> 0.05) in response to training, yet there was a significant change in percent body fat (
p
= 0.03), percent fat-free mass (
p
= 0.03), and absolute fat-free mass (
p
= 0.03) in TRAD but not PER. No change occurred in KE (
p
= 0.36) or KF torque (
p
= 0.75) in response to training and there was no group-by-time interaction (
p
> 0.05).
Conclusions
Low-volume HIIT improved VO
2
max and body composition but did not modify muscular strength, which suggests that obese women desiring to increase strength should initiate more intense HIIT or partake in formal resistance training.
Arm cycling ergometry (ACE) leads to a lower maximal oxygen uptake (VO
max) than cycling which is related to a smaller active muscle mass. This study compared estimates of fat and carbohydrate ...oxidation (FOx and CHOOx) between progressive exercise protocols varying in stage duration in an attempt to create a standard exercise protocol for determining substrate metabolism using ACE. Four men and seven women (age = 24 ± 9 yr) unfamiliar with ACE completed incremental exercise to determine peak power output and VO
peak. During two subsequent sessions completed after an overnight fast, they completed progressive ACE using 3- or 5-min stages during which FOx, CHOOx, and blood lactate concentration (BLa) were measured. Results showed no difference (p > 0.05) in FOx, CHOOx, or BLa across stage duration, and there was no difference in maximal fat oxidation (0.16 ± 0.08 vs. 0.13 ± 0.07 g/min, p = 0.07). However, respiratory exchange ratio in response to the 3 min stage duration was significantly lower than the 5 min duration (0.83 ± 0.05 vs. 0.86 ± 0.03, p = 0.04, Cohen's d = 0.76). Results suggest that a 3 min stage duration is preferred to assess substrate metabolism during upper-body exercise in healthy adults.
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