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Adaptations to aerobic interval training: Interactive effects of exercise intensity and total work duration

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Abstract

To compare the effects of three 7-week interval training programs varying in work period duration but matched for effort in trained recreational cyclists. Thirty-five cyclists (29 male, 6 female, VO(2peak) 52 ± 6 mL kg/min) were randomized to four training groups with equivalent training the previous 2 months (∼6 h/wk, ∼1.5 int. session/wk). Low only (n=8) trained 4-6 sessions/wk at a low-intensity. Three groups (n=9 each) trained 2 sessions/wk × 7 wk: 4 × 4 min, 4 × 8 min, or 4 × 16 min, plus 2-3 weekly low-intensity bouts. Interval sessions were prescribed at the maximal tolerable intensity. Interval training was performed at 88 ± 2, 90 ± 2, and 94 ± 2% of HR(peak) and 4.9, 9.6, and 13.2 mmol/L blood lactate in 4 × 16, 4 × 8, and 4 × 4 min groups, respectively (both P<0.001). 4 × 8min training induced greater overall gains in VO(2) peak, power@VO(2) peak, and power@4 mM bLa- (Mean ± 95%CI): 11.4 (8.0-14.9), vs 4.2 (0.4-8.0), 5.6 (2.1-9.1), and 5.5% (2.0-9.0) in Low, 4 × 16, and 4 × 4 min groups, respectively (P<0.02 for 4 × 8 min vs all other groups). Interval training intensity and accumulated duration interact to influence the adaptive response. Accumulating 32 min of work at 90% HR max induces greater adaptive gains than accumulating 16 min of work at ∼95% HR max despite lower RPE.
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... The typical 4 × 4 min session is likely to be performed at a higher intensity level than a 16 min exercise performed in continuous modality [30]. Seiler et al. reported that the maximal tolerable intensity for 4 × 4 min was 94 ± 2% of maximal heart rate when interspersed with 2 min passive recovery [32]; in HIIT studies, an active recovery (3 min at 70% HRmax) was added to this maximal effort. Conversely, because of the nonlinear relationship between exercise intensity and energy expenditure, typical MICT exercise appears to be far from the exercise dose performed during typical HIIT. ...
... It may be assumed that the typical HIIT exercise resulting from the energy-based equalizing method reached a maximum of energy expenditure and was exhausting, while MICT represented relatively easy training. This assumption is supported by significantly higher ratings of perceived exertion (RPE) following HIIT sessions [25,33,34], and some authors argued that energy-based methods for equalization underestimate the work that athletes are able to perform at lower intensities [32,35]. Such differences in session-induced exertion should be considered as a possible methodological bias that is likely to become more pronounced with increases in intensity differences between programs. ...
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Based on comparisons to moderate continuous exercise (MICT), high-intensity interval training (HIIT) is becoming a worldwide trend in physical exercise. This raises methodological questions related to equalization of exercise dose when comparing protocols. The present scoping review aims to identify in the literature the evidence for protocol equalization and the soundness of methods used for it. PubMed and Scopus databases were searched for original investigations comparing the effects of HIIT to MICT. A total of 2041 articles were identified, and 169 were included. Of these, 98 articles equalized protocols by utilizing energy-based methods or exercise volume (58 and 31 articles, respectively). No clear consensus for protocol equalization appears to have evolved over recent years. Prominent equalization methods consider the exercise dose (i.e., energy expenditure/production or total volume) in absolute values without considering the nonlinear nature of its relationship with duration. Exercises resulting from these methods induced maximal exertion in HIIT but low exertion in MICT. A key question is, therefore, whether exercise doses are best considered in absolute terms or relative to individual exercise maximums. If protocol equalization is accepted as an essential methodological prerequisite, it is hypothesized that comparison of program effects would be more accurate if exercise was quantified relative to intensity-related maximums.
... Based on this, we can easily claim that the lower BF% can influence success in cross-country running, which appears to influence muscle mass and to balance hormone levels during training. In agreement with the present study, several studies have shown that a decrease in BF% is associated with performance in long-distance running (Seiler, Jøranson, Olesen & Hetlelid, 2013;Haugen et al., 2018;Arazi, Mirzaei & Nobari, 2015;Abraham, 2010). The decrease in BF% is generally associated with lower intensity endurance training and metabolic changes in trained muscle. ...
... The decrease in BF% is generally associated with lower intensity endurance training and metabolic changes in trained muscle. It is common in endurance athletes where reduced BF% significantly influences long-distance running performance (Seiler et al., 2013). This is consistent with the findings of this study where the participants were found to have lower BF%. ...
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In recent years, there has been an increasing interest in the morphological and physiological characteristics for many sporting codes. Morphological and physiological testing is an important tool for cross-country athletes and coaches and assists in the training intensity prescription, monitoring of training adaptation and profiling athletes for specific competitions. So far, however, there has been few reports on senior male cross-country athletes. The aim of this research was to determine the relationship between morphological and physiological characteristics of senior male cross-country athletes in Gauteng province, South Africa. Forty males (age: 20-35 years; height: 173.09 cm; weight: 63.05 kg) who competed in the Central Gauteng Senior Cross-Country Championships competition were invited to participate in this study. Parameters tested included stature, body weight, seven skinfolds, body fat percentage, lean body mass, somatotype and 10km time measured. The maximal oxygen consumption, running economy and two ventilatory thresholds (VT1 and VT2) were calculated using online assessments of each participant as explained in the methods of this study. Data were analysed using descriptive statistics (SPSS, v.21) and Pearson coefficient of correlation procedures. A significant difference was observed between athletes who trained for <45 minutes and those who trained for >45 minutes per day by an independent t-test. An independent t-test was used to determine significant differences between the two groups. The data were collected experimentally by using a self-administered questionnaire for the medical and sporting status of the runners. The results of this study indicated mean values of body weight (63.05 kg), body fat percentage (8.04 %), sum of seven skinfolds (34.12 mm), lean body mass (59.24 kg) and somatotype (i.e., endomorph, mesomorph, and ectomorph ratios) (1.80, 1.40. and 2.80) respectively. The mean values for maximum oxygen consumption (V̇ O2max) (63.50 mlO2 . kg˗1.min-1 ), running economy (at 12 km·hr -1 32.8 L/min, 14.5 km·hr -1 41.70 L/min, 16 km·hr -1 56 L/min, 19.2 km·hr -1 30.60 L/min), ventilatory threshold (2.95 L/min-1 ), maximum heart rate (191.00 bpm), respiratory exchange ratio (1.23) and average 10 km running speed (16.24 km·hr -1 ) were also determined. The VT1 and VT2 were calculated and at the intensities corresponding to the last point before a first non-linear increase in both VT1 and VT2. The senior male cross-country athletes showed higher values for O2 expressed relative to morphological and physiological factor. The above measurements were captured in Johannesburg at the following altitude (1753 m), barometric pressure (82.54 kPa), air density (0.98 kg/m2 at 20 ºC/ (293 k). These characteristics are generally associated with cross-country iii runners, suggesting that senior male cross-country athletes in Gauteng province, South Africa, are professional athletes. There were no significant V̇ O2max, RE and personal best 10 km time differences between participants who trained <45 minutes and those who trained >45 minutes per day during training sessions (p > 0.05). However, there were significant body weight (p = 0.028) and BF% (p = 0.030) differences between the two groups. It can thus suggest that the duration of the daily training session has a direct effect on some morphological characteristics of athletes, but no effect on others. The analysis showed that athletes of various endurance events statistically differ in morphological measures, especially in dimensions of BW and BF%. Further, highlight the importance of morphological and physiological factors in cross�country running. This research will serve as a basis for future studies and will provide information on senior male cross-country athletes, which can be referred to by coaches and sports scientists who train athletes during the competition preparation phase. KEY WORDS: anthropometry, V̇ O2max, running economy, ventilatory threshold
... Based on this, we can easily claim that the lower BF% can influence success in cross-country running, which appears to influence muscle mass and to balance hormone levels during training. In agreement with the present study, several studies have shown that a decrease in BF% is associated with performance in long-distance running (Seiler, Jøranson, Olesen & Hetlelid, 2013;Haugen et al., 2018;Arazi, Mirzaei & Nobari, 2015;Abraham, 2010). The decrease in BF% is generally associated with lower intensity endurance training and metabolic changes in trained muscle. ...
... The decrease in BF% is generally associated with lower intensity endurance training and metabolic changes in trained muscle. It is common in endurance athletes where reduced BF% significantly influences long-distance running performance (Seiler et al., 2013). This is consistent with the findings of this study where the participants were found to have lower BF%. ...
Article
Full-text available
In recent years, there has been an increasing interest in the morphological and physiological characteristics for many sporting codes. Morphological and physiological testing is an important tool for cross-country athletes and coaches and assists in the training intensity prescription, monitoring of training adaptation and profiling athletes for specific competitions. So far, however, there has been few reports on senior male cross-country athletes. The aim of this research was to determine the relationship between morphological and physiological characteristics of senior male cross-country athletes in Gauteng province, South Africa. Forty males (age: 20-35 years; height: 173.09 cm; weight: 63.05 kg) who competed in the Central Gauteng Senior Cross-Country Championships competition were invited to participate in this study. Parameters tested included stature, body weight, seven skinfolds, body fat percentage, lean body mass, somatotype and 10km time measured. The maximal oxygen consumption, running economy and two ventilatory thresholds (VT1 and VT2) were calculated using online assessments of each participant as explained in the methods of this study. Data were analysed using descriptive statistics (SPSS, v.21) and Pearson coefficient of correlation procedures. A significant difference was observed between athletes who trained for <45 minutes and those who trained for >45 minutes per day by an independent t-test. An independent t-test was used to determine significant differences between the two groups. The data were collected experimentally by using a self-administered questionnaire for the medical and sporting status of the runners. The results of this study indicated mean values of body weight (63.05 kg), body fat percentage (8.04 %), sum of seven skinfolds (34.12 mm), lean body mass (59.24 kg) and somatotype (i.e., endomorph, mesomorph, and ectomorph ratios) (1.80, 1.40. and 2.80) respectively. The mean values for maximum oxygen consumption (V̇ O2max) (63.50 mlO2 . kg˗1.min-1 ), running economy (at 12 km·hr -1 32.8 L/min, 14.5 km·hr -1 41.70 L/min, 16 km·hr -1 56 L/min, 19.2 km·hr -1 30.60 L/min), ventilatory threshold (2.95 L/min-1 ), maximum heart rate (191.00 bpm), respiratory exchange ratio (1.23) and average 10 km running speed (16.24 km·hr -1 ) were also determined. The VT1 and VT2 were calculated and at the intensities corresponding to the last point before a first non-linear increase in both VT1 and VT2. The senior male cross-country athletes showed higher values for O2 expressed relative to morphological and physiological factor. The above measurements were captured in Johannesburg at the following altitude (1753 m), barometric pressure (82.54 kPa), air density (0.98 kg/m2 at 20 ºC/ (293 k). These characteristics are generally associated with cross-country iii runners, suggesting that senior male cross-country athletes in Gauteng province, South Africa, are professional athletes. There were no significant V̇ O2max, RE and personal best 10 km time differences between participants who trained <45 minutes and those who trained >45 minutes per day during training sessions (p > 0.05). However, there were significant body weight (p = 0.028) and BF% (p = 0.030) differences between the two groups. It can thus suggest that the duration of the daily training session has a direct effect on some morphological characteristics of athletes, but no effect on others. The analysis showed that athletes of various endurance events statistically differ in morphological measures, especially in dimensions of BW and BF%. Further, highlight the importance of morphological and physiological factors in cross�country running. This research will serve as a basis for future studies and will provide information on senior male cross-country athletes, which can be referred to by coaches and sports scientists who train athletes during the competition preparation phase. KEY WORDS: anthropometry, V̇ O2max, running economy, ventilatory threshold.
... In fact, a study conducted in amateur soccer players comparing HIRT with traditional strength training showed that both cardiorespiratory and metabolic responses were significantly higher in HIRT [22]. Such a physiological stress, and despite interactions with training regimen variables (e.g., intensity, duration, work-to-rest ratio), seems to elicit positive adaptation on aerobic power [28] independently of regimen used. Moreover, the training characteristics of HIRT seems also to improve anaerobic performance pending adjustments in time of bouts and recovery in between [29]. ...
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Abstract: Purpose: The aim of this study was to test the effects of high-intensity resistance training (HIRT) intervention on the physical fitness, hormonal and antioxidant factors of adult male soccer players. Methods: A randomized controlled study design was implemented. Eighteen soccer players (age: 20.3 ± 0.66 years; stature: 174.0 ± 6.01 cm; body mass: 69.1 ± 6.4 kg; body mass index: 22.8 ± 1.6 kg/m2 ) voluntarily participated in this study. Players were assessed before and after an intervention lasting 8 weeks, with three training sessions a week. Assessments of physical fitness included the Yo-Yo intermittent recovery test level 1 (YYIRT1), 10-, 20-, and 30 m sprint time (ST), running-based anaerobic sprint test (RAST) and change-of-direction time (COD). Hormonal tests included cortisol, testosterone and growth hormone (GH), whereas the antioxidant assessment included superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH). Results: Between-group analysis revealed no significant differences at baseline, whereas it revealed that HIRT presented significant better results than the control group on YYIRT (p = 0.032), 10 m ST (p = 0.041), 20 m ST (p = 0.040), 30 m ST (p = 0.044), RAST (p = 0.013), and COD (p = 0.031) after the intervention period. The within group analysis revealed that the HIRT group significantly improved the YYIRT1 (p < 0.001), VO2max (p < 0.001), 10 m ST (p < 0.001), 20 m ST (p = 0.006), 30 m ST (p < 0.001), RAST (p < 0.001) and COD (p < 0.001). Moreover, HIRT group significantly reduced the cortisol (p < 0.001) and MDA (p = 0.021), whereas it significantly increased the GH (p < 0.001), testosterone (p < 0.001), SOD (p = 0.009) and GSH (p = 0.005). Conclusions: The HIRT is effective for improving physical fitness, revealing significant better adaptations than controls. Moreover, hormonal and antioxidant adaptations are also confirmed after HIRT intervention.
... It is important to consider that by constitutively and then operationally defining at the amalgamated level, there is a lack of consideration (and therefore numerical/quantitative representation) of the interaction between 'exercise duration', 'exercise frequency' and 'exercise intensity' and their influence on acute and chronic training effects. 9 It was made clear by Renfree et al 7 that a differing combination of 'exercise intensity' and 'exercise duration' can render almost identical 'training load' values, despite differing effects on training adaption and injury risk. Unfortunately, the relationships between 'exercise duration', 'exercise frequency', 'exercise intensity', and 'training load' remain ambiguous. ...
... Numerous studies suggest other intensity domains to be of interest [7,45]. Indeed, HIIT performed within the severe and extreme intensity domains has gained popularity over the last years, notably through the contribution of Tabata [46,47], Gibala [48][49][50][51], and Seiler [52,53]. Moreover, a cycling race can be seen as a complex, stochastic form of HIIT, composed of inevitable supramaximal efforts. ...
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High-Intensity Interval Training (HIIT) is a time-efficient training method suggested to improve health and fitness for the clinical population, healthy subjects, and athletes. Many parameters can impact the difficulty of HIIT sessions. This study aims to highlight and explain, through logical deductions, some limitations of the Skiba and Coggan models, widely used to prescribe HIIT sessions in cycling. We simulated 6198 different HIIT training sessions leading to exhaustion, according to the Skiba and Coggan-Modified (modification of the Coggan model with the introduction of an exhaustion criterion) models, for three fictitious athlete profiles (Time-Trialist, All-Rounder, Sprinter). The simulation revealed impossible sessions (i.e., requiring athletes to surpass their maximal power output over the exercise interval duration), characterized by a few short exercise intervals, performed in the severe and extreme intensity domains, alternating with long recovery bouts. The fraction of impossible sessions depends on the athlete profile and ranges between 4.4 and 22.9% for the Skiba model and 0.6 and 3.2% for the Coggan-Modified model. For practitioners using these HIIT models, this study highlights the importance of understanding these models’ inherent limitations and mathematical assumptions to draw adequate conclusions from their use to prescribe HIIT sessions.
... All training sessions were performed on an athletic track (400 m). Training volumes (running distances) were identical in the two groups, but the intensities were different and determined according to maximum heart rate (HRmax): low intensity ≈60% of HRmax, moderate endurance training 70-80% of HRmax and intense endurance training 85-95% HRmax [26,27]. Training sessions were performed during the afternoon (3:30 to 5:00 p.m.). ...
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Citation: Dridi, R.; Dridi, N.; Govindasamy, K.; Gmada, N.; Aouadi, R.; Guénard, H.; Laher, I.; Saeidi, A.; Suzuki, K.; Hackney, A.C.; et al. Effects of Endurance Training Intensity on Pulmonary Diffusing Capacity at Rest and after Maximal
... All training sessions were performed on an athletic track (400 m). Training volumes (running distances) were identical in the two groups, but the intensities were different and determined according to maximum heart rate (HRmax): low intensity ≈60% of HRmax, moderate endurance training 70-80% of HRmax and intense endurance training 85-95% HRmax [26,27]. Training sessions were performed during the afternoon (3:30 to 5:00 p.m.). ...
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This study compared the effects of varying aerobic training programs on pulmonary diffusing capacity (TLCO), pulmonary diffusing capacity for nitric oxide (TLNO), lung capillary blood volume (Vc) and alveolar–capillary membrane diffusing capacity (DM) of gases at rest and just after maximal exercise in young athletes. Sixteen healthy young runners (16–18 years) were randomly assigned to an intense endurance training program (IET, n = 8) or to a moderate endurance training program (MET, n = 8). The training volume was similar in IET and MET but with different work intensities, and each lasted for 8 weeks. Participants performed a maximal graded cycle bicycle ergometer test to measure maximal oxygen consumption (VO2max) and maximal aerobic power (MAP) before and after the training programs. Moreover, TLCO, TLNO and Vc were measured during a single breath maneuver. After eight weeks of training, all pulmonary parameters with the exception of alveolar volume (VA) and inspiratory volume (VI) (0.104 < p < 0889; 0.001 < ES < 0.091), measured at rest and at the end of maximal exercise, showed significant group × time interactions (p < 0.05, 0.2 < ES < 4.0). Post hoc analyses revealed significant pre-to-post decreases for maximal heart rates (p < 0.0001, ES = 3.1) and improvements for VO2max (p = 0.006, ES = 2.22) in the IET group. Moreover, post hoc analyses revealed significant pre-to-post improvements in the IET for DM, TLNO, TLCO and Vc (0.001 < p < 0.0022; 2.68 < ES < 6.45). In addition, there were increases in Vc at rest, VO2max, TLNO and DM in the IET but not in the MET participants after eight weeks of training with varying exercise intensities. Our findings suggest that the intensity of training may represent the most important factor in increasing pulmonary vascular function in young athletes.
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