Supramaximal Exercise Research Articles

One-HIIT wonder: Can music make high-intensity interval training more pleasant?

The use of music as an aid to recovery during and after exercise is an area of growing scientific interest. We investigated the effects of in-task, asynchronous music and respite–active music (i.e., music used for active recovery in between high-intensity exercise bouts) on a range of psychological, psychophysical and psychophysiological outcomes. Participants (N = 28; 14 females) made five laboratory visits for: (a) pre-test/familiarisation; (b) fast-tempo music during supramaximal exercise bouts and medium-tempo music during active-recovery periods; (c) fast-tempo music during exercise and no music during recovery; (d) no music during exercise and medium-tempo music during recovery; and (e) a no-music (throughout) control. A cycle ergometer-based HIIT protocol comprising 6 × 60-s bouts at 100% Wmax with 75-s active recovery was administered. Measures were taken at the end of supramaximal bouts and active recovery periods (RPE, state attention, core affect, state motivation), then upon cessation of the protocol (remembered pleasure and exercise enjoyment). Heart rate and heart rate variability (HRV) measures were taken throughout. The music manipulations only had an effect on state motivation, which was higher (p = 0.036) in the fast tempo–medium tempo condition compared to no-music control (Cohen’s d = 0.49), and the SDNN component of HRV, which was lower (p = 0.007) in the fast-tempo–no-music condition compared to control (Cohen’s d = 0.32). Collectively, the present findings do not support any of the study hypotheses regarding the music-related manipulations, and do not concur with the findings of related studies (e.g., Karageorghis et al., 2021). The unexpected results are discussed with reference to extant theory, and recommendations are offered in regard to music-related applications.

A New Training Load Quantification Method at Supramaximal Intensity and Its Application in Injuries Among Members of an International Volleyball Team.

Bouzigues, T, Maurelli, O, Imbach, F, Prioux, J, and Candau, R. A new training load quantification method at supramaximal intensity and its application in injuries among members of an international volleyball team. J Strength Cond Res 38(8): 1453-1463, 2024-The quantification of training loads (TLs) is essential for optimizing jump performance and reducing the occurrence of injuries. This study aimed to (a) propose a new method for quantifying TLs in explosive exercises, (b) determine the nature of the relationship between TLs dynamics and injury occurrence, and (c) assess a TL critical for training schedule purposes, above which the risk of injury occurrence becomes unacceptable. This study was conducted with 11 male volleyball players on a national team during a 5-month international competitive period. The proposed new method for quantifying TLs is based on a weighting factor applied to relative jumping intensities, determined by the number of sustainable jumps and their intensities measured by G-Vert accelerometer. The relationship between TLs dynamics and injury occurrence was assessed using a variable dose-response model. A high coefficient of determination was found between the maximum number of jumps possible and their intensities ( r2 = 0.94 ± 0.14, p < 0.001), indicating a strong physiological relationship between jumping intensities and the constraints imposed. The occurrence of injury was dependent on TLs dynamics for 2 players ( r2 = 0.26 ± 0.01; p < 0.001). The TL critical corresponded to 11 jumps over 80% of maximum jump height during games and approximately 130 jumps at <80% of maximal jump height. The present study proposes a new approach for quantifying supramaximal exercises and provides tools for training schedules and the prevention of volleyball injuries.

Acute Effects of Combined Hypoxia and Fatigue on Balance in Young Men

The aim of this study was to determine the effects of maximal exercise and maximal exercise under hypoxic conditions on balance, the strategies of the balance-maintenance process and its sensory organization. A total of 60 men were randomly allocated to three experimental groups and a control group. All participants completed the sensory organization test for assessing balance. Participants in the experimental groups performed the same test after an hour of normobaric hypoxia (the first group), after supramaximal exercise (the second group) and after supramaximal exercise combined with 60 min of hypoxia exposure (the third group). The control group performed the test after 60 min of passive rest. Normobaric hypoxia conditions corresponded to an altitude of 2950 m (FIO2 15%). Physical effort in normoxia and hypoxia significantly impaired the participants’ stability on a stable platform with eyes open (η2 = 0.711, p = 0.001; η2 = 0.583, p = 0.001, respectively). On an unstable platform, a significant improvement in stability indices was observed in the group undertaking the exercise in hypoxia (p = 0.04, η2 = 0.249). The experimental conditions increased the role of hip strategies in maintaining balance in the experimental groups during trials requiring somatosensory information. An analysis of sensory organization shows that maximal effort in hypoxia increases the role of somatosensory (p = 0.002, η2 = 0.69) and vestibular (p = 0.02, η2 = 0.34) information, whereas hypoxia alone increases reliance on visual (p = 0.03, η2 = 0.38) and vestibular (p = 0.02, η2 = 0.36) information. This study indicates that individuals have poorer stability after maximal exercise, which may cause difficulties in engaging in some dynamic forms of activity, especially those with a large number of visual stimuli.

The effect of maximum and supramaximal strength exercises on developing motor response speed and the skill performance of spike for volleyball players

The study aimed at the possibility of breaking the adjustment in the body muscles that are relevant to the volleyball player in terms of connectivity in the development of motor velocity through extreme and ultra-maximum force exercises. The researchers used the experimental method to solve the search problem. (24) A player in deliberate style, and the two researchers used several tools and methods, and this vocabulary was sunk for a period of.(4) weeks, 3 modules per week and 12 modules, 1 module time.(90 minutes) Motor speed measurement tests were used because of their importance in achieving the player's goal of exercise and the overwhelming strike test, which measures the performance level of offensive skills in volleyball. Tests were conducted before and after the use of extreme and super-maximum force exercises

Anaerobic and aerobic contributions to repeated supramaximal cycling exercises and their adaptation to high-intensity interval training in obese perimenopausal and postmenopausal women.

This study investigated the anaerobic and aerobic contributions to total energy release during repeated supramaximal cycling exercises (SCE) and their adaptation in response to 6 weeks of high-intensity interval training (HIIT) in obese perimenopausal and postmenopausal women. Nineteen perimenopausal women and 21 postmenopausal women with an average age of 50.1 years participated in the 6-week HIIT intervention. Before and after the training, the accumulated oxygen deficits (mL·min -1 ) and anaerobic and aerobic contributions (%) were measured in all groups via repeated SCE. The results showed that, before training, the anaerobic contributions to repeated SCE did not differ between the perimenopausal and postmenopausal women for the first three repetitions. However, a higher decrease was reported for postmenopausal women at the fourth and fifth repetitions ( P < 0.01, respectively). After HIIT, anaerobic contributions increased significantly in both groups ( P < 0.01, respectively). Nevertheless, postmenopausal women still had significantly lower anaerobic contributions to repeated SCE compared with perimenopausal women ( P < 0.01, respectively). Multiple linear regression analysis indicated that menopause status was an independent predictor of anaerobic contribution, accounting for 17%, 21%, 15%, 19%, and 22% of variations (β = 0.28, P = 0.03; β = 0.29, P = 0.04; β = 0.18, P = 0.05; β = 0.22, P = 0.05; and β = 0.33, P = 0.03 for the first to the fifth repetitions consecutively for perimenopausal vs postmenopausal groups). A 6-week HIIT intervention increased the anaerobic contributions to energy in response to repeated SCE in obese perimenopausal and postmenopausal women. However, postmenopausal women had lower anaerobic contributions at the fourth and fifth repetitions mainly due to the effects of menopause.

Physiological Responses to Supramaximal Running Exercise with End-Expiratory Breath Holding up to the Breaking Point.

This study aimed to assess the physiological responses to repeated running exercise performed at supramaximal intensity and with end-expiratory breath holding (EEBH) up to the breaking point. Eight male runners participated in two running testing sessions on a motorized treadmill. In the first session, participants performed two sets of 8 repetitions at 125% of maximal aerobic velocity and with maximum EEBH. Each repetition started at the onset of EEBH and ended at its release. In the second session, participants replicated the same procedure, but with unrestricted breathing (URB). The change in cerebral and muscle oxygenation (Δ[Hbdiff]), total haemoglobin concentration (Δ[THb]) and muscle reoxygenation were continuously assessed. End-tidal oxygen (PETO2) and carbon dioxide pressure (PETCO2), arterial oxygen saturation (SpO2) and heart rate (HR) were also measured throughout exercise.On average, EEBH was maintained for 10.1 ± 1 s. At the breaking point of EEBH, PETO2 decreased to 54.1 ± 8 mmHg, whereas PETCO2 increased to 74.8 ± 3.1 mmHg. At the end of repetitions, SpO2 (nadir values 74.9 ± 5.0 vs. 95.7 ± 0.8%) and HR were lower with EEBH than with URB. Cerebral and muscle Δ[Hbdiff] were also lower with EEBH, whereas this condition induced higher cerebral and muscle Δ[THb] and greater muscle reoxygenation. This study showed that performing repeated bouts of supramaximal running exercises with EEBH up to the breaking point induced a fall in arterial, cerebral and muscle oxygenation compared with the URB condition. These phenomena were accompanied by increases in regional blood volume likely resulting from compensatory vasodilation to preserve oxygen delivery to the brain and muscles.

Supramaximal Testing to Confirm the Achievement of V̇O 2max in Acute Hypoxia.

We sought to determine if supramaximal exercise testing confirms the achievement of V̇O 2max in acute hypoxia. We hypothesized that the incremental and supramaximal V̇O 2 will be sufficiently similar in acute hypoxia. Twenty-one healthy adults (males n = 13, females n = 8) completed incremental and supramaximal exercise tests in normoxia and acute hypoxia (fraction inspired oxygen = 0.14) separated by at least 48 h. Incremental exercise started at 80 and 60 W in normoxia and 40 and 20 W in hypoxia for males and females, respectively, with all increasing by 20 W each minute until volitional exhaustion. After a 20-min postexercise rest period, a supramaximal test at 110% peak power until volitional exhaustion was completed. Supramaximal exercise testing yielded a lower V̇O 2 than incremental testing in hypoxia (3.11 ± 0.78 vs 3.21 ± 0.83 L·min -1 , P = 0.001) and normoxia (3.71 ± 0.91 vs 3.80 ± 1.02 L·min -1 , P = 0.01). Incremental and supramaximal V̇O 2 were statistically similar, using investigator-determined equivalence bounds ±150 mL·min -1 , in hypoxia ( P = 0.02, 90% confidence interval [CI] = 0.05-0.14) and normoxia ( P = 0.03, 90% CI = 0.01-0.14). Likewise, using ±2.1 mL·kg -1 ·min -1 bounds, incremental and supramaximal V̇O 2 values were statistically similar in hypoxia ( P = 0.04, 90% CI = 0.70-2.0) and normoxia ( P = 0.04, 90% CI = 0.30-2.0). Despite differences in the oxygen cascade, incremental and supramaximal V̇O 2 values were statistically similar in both hypoxia and normoxia, demonstrating the utility of supramaximal verification of V̇O 2max in the setting of acute hypoxia.

Acute effects of isotonic eccentric exercise on the neuromuscular function of knee extensors vary according to the motor task: impact on muscle strength profiles, proprioception and balance.

Eccentric exercise has often been reported to result in muscle damage, limiting the muscle potential to produce force. However, understanding whether these adverse consequences extend to a broader, functional level is of apparently less concern. In this study, we address this issue by investigating the acute and delayed effects of supramaximal isotonic eccentric exercise on neuromuscular function and motor performance of knee extensors during tasks involving a range of strength profiles, proprioception, and balance. Fifteen healthy volunteers (23.2 ± 2.9 years old) performed a unilateral isotonic eccentric exercise of the knee extensors of their dominant lower limb (4 × 10 reps at 120% of one Repetition Maximum (1RM)). The maximum voluntary isometric contraction (MVC), rate of force development (RFD), force steadiness of the knee extensors, as well as knee joint position sense and mediolateral (MLI) and anteroposterior stability (API) of the dominant lower limb, were measured pre-, immediately, and 24 h after the eccentric exercise. The EMG amplitude of the vastus medialis (VM) and biceps femoris (BF) were concomitantly evaluated. MVC decreased by 17.9% immediately after exercise (P < 0.001) and remained reduced by 13.6% 24 h following exercise (P < 0.001). Maximum RFD decreased by 20.4% immediately after exercise (P < 0.001) and remained reduced by 15.5% at 24 h (P < 0.001). During the MVC, EMG amplitude of the VM increased immediately after exercise while decreasing during the RFD task. Both values returned to baseline 24 h after exercise. Compared to baseline, force steadiness during submaximal isometric tasks reduced immediately after exercise, and it was accompanied by an increase in the EMG amplitude of the VM. MLI and knee joint position sense were impaired immediately after isotonic eccentric exercise (P < 0.05). While MLI returned to baseline values 24 h later, the absolute error in the knee repositioning task did not. Impairments in force production tasks, particularly during fast contractions and in the knee joint position sense, persisted 24 h after maximal isotonic eccentric training, revealing that neuromuscular functional outputs were affected by muscle fatigue and muscle damage. Conversely, force fluctuation and stability during the balance tasks were only affected by muscle fatigue since fully recovered was observed 24 h following isotonic eccentric exercise.

Intense interval exercise induces greater changes in post-exercise metabolism compared to submaximal exercise in middle-aged adults.

High-intensity interval training (HIIT) and sprint interval training (SIT) consistently elevate post-exercise metabolism compared to moderate-intensity continuous training (MICT) in young adults (18-25years), however few studies have investigated this in middle-aged adults. To assess the effect of exercise intensity on post-exercise metabolism following submaximal, near-maximal, and supramaximal exercise protocols in middle-aged adults. 12 participants (8 females; age: 44 ± 10years; O2max: 35.73 ± 9.97mL·kg-1min-1) had their oxygen consumption ( O2) measured during and for 2h following 4 experimental sessions: (1) no-exercise control (CTRL); (2) MICT exercise (30min at 65% O2max); (3) HIIT exercise (10 × 1min at 90% maximum heart rate with 1min rest); and (4) modified-SIT exercise (8 × 15s "all-out" efforts with 2min rest). Between session differences for O2 and fat oxidation were compared. O2 consumed post-exercise was elevated during the 1st h and 2nd h following HIIT (15.9 ± 2.6, 14.7 ± 2.3L; P < 0.036, d > 0.98) and modified-SIT exercise (16.9 ± 3.3, 15.30 ± 3.4L; P < 0.041, d > 0.96) compared to CTRL (13.3 ± 1.9, 12.0 ± 2.5 L) while modified-SIT was also elevated vs HIIT in the 1st h (P < 0.041, d > 0.96). Total post-exercise O2 consumption was elevated following all exercise sessions (MICT: 27.7 ± 4.1, HIIT: 30.6 ± 4.8, SIT: 32.2 ± 6.6L; P < 0.027, d > 1.03) compared to CTRL (24.9 ± 4.1L). Modified-SIT exercise increased fat oxidation (0.103 ± 0.019gmin-1) compared to all sessions post-exercise (CTRL: 0.059 ± 0.025, MICT: 0.075 ± 0.022, HIIT: 0.081 ± 0.021g·min-1; P < 0.007, d > 1.30) and HIIT exercise increased compared to CTRL (P = 0.046, d = 0.87). Exercise intensity has an important effect on post-exercise metabolism in middle-aged adults.

Determinants of the maximal functional reserve during repeated supramaximal exercise by humans: The roles of Nrf2/Keap1, antioxidant proteins, muscle phenotype and oxygenation

When high-intensity exercise is performed until exhaustion a “functional reserve” (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VO2max interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR. Then, we determined which muscle phenotypic features could account for the variability in functional reserve in humans. Exercise performance, cardiorespiratory variables, oxygen deficit, and brain and muscle oxygenation (near-infrared spectroscopy) were measured, and resting muscle biopsies were obtained from 43 young healthy adults (30 males). Males and females had similar aerobic (VO2max per kg of lower extremities lean mass (LLM): 166.7 ± 17.1 and 166.1 ± 15.6 ml kg LLM−1.min−1, P = 0.84) and anaerobic fitness (similar performance in the Wingate test and maximal accumulated oxygen deficit when normalized to LLM). The maximal FR was similar in males and females when normalized to LLM (1.84 ± 0.50 and 2.05 ± 0.59 kJ kg LLM−1, in males and females, respectively, P = 0.218). This FR depends on an obligatory component relying on a reserve in glycolytic capacity and a putative component generated by oxidative phosphorylation. The aerobic component depends on brain oxygenation and phenotypic features of the skeletal muscles implicated in calcium handling (SERCA1 and 2 protein expression), oxygen transport and diffusion (myoglobin) and redox regulation (Keap1). The glycolytic component can be predicted by the protein expression levels of pSer40-Nrf2, the maximal accumulated oxygen deficit and the protein expression levels of SOD1. Thus, an increased capacity to modulate the expression of antioxidant proteins involved in RONS handling and calcium homeostasis may be critical for performance during high-intensity exercise in humans.

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women.

Despite the growing popularity of high-intensity anaerobic exercise, little is known about the acute effects of this form of exercise on cardiovascular hemodynamics or autonomic modulation, which might provide insight into the individual assessment of responses to training load. The purpose of this study was to compare blood pressure and autonomic recovery following repeated bouts of acute supramaximal exercise in Black and White women. A convenience sample of twelve White and eight Black young, healthy women were recruited for this study and completed two consecutive bouts of supramaximal exercise on the cycle ergometer with 30 min of recovery in between. Brachial and central aortic blood pressures were assessed by tonometry (SphygmoCor Xcel) at rest and 15-min and 30-min following each exercise bout. Central aortic blood pressure was estimated using brachial pressure waveforms and customized software. Autonomic modulation was measured in a subset of ten participants by heart-rate variability and baroreflex sensitivity. Brachial mean arterial pressure and diastolic blood pressure were significantly higher in Blacks compared to Whites across time (race effect, p = 0.043 and p = 0.049, respectively). Very-low-frequency and low-frequency bands of heart rate variability, which are associated with sympathovagal balance and vasomotor tone, were 22.5% and 24.9% lower, respectively, in Blacks compared to Whites (race effect, p = 0.045 and p = 0.006, respectively). In conclusion, the preliminary findings of racial differences in blood pressure and autonomic recovery following supramaximal exercise warrant further investigations of tailored exercise prescriptions for Blacks and Whites.

Intense interval exercise induces lactate accumulation and a greater suppression of acylated ghrelin compared with submaximal exercise in middle-aged adults.

Exercise in young adults (18-25 yr) suppresses appetite in a dose-response relationship with exercise intensity. Although several mechanisms have been proposed to explain this response, lactate is the most well established. To date, no study has investigated this specifically in middle-aged adults where the appetite response to a meal is different. To explore the effects of submaximal, near maximal, and supramaximal intensity exercise on appetite regulation in middle-aged adults. Nine participants (age: 45 ± 10 yr) completed four experimental sessions: 1) no-exercise control (CTRL); 2) moderate-intensity continuous training [MICT; 30 min, 65% maximal oxygen consumption (V̇o2max)]; 3) high-intensity interval training (HIIT; 10 × 1 min efforts, 90% heart rate maximum, 1 min recovery); and 4) sprint interval training (SIT; 8 × 15 s "all-out" efforts, 2 min recovery). Acylated ghrelin, active glucagon-like peptide-1 (GLP-1), active peptide tyrosine tyrosine (PYY), lactate, and subjective appetite perceptions were measured pre-exercise, 0-, 30-, and 90-min postexercise. Energy intake was recorded the day before and day of each session. Acylated ghrelin was suppressed (P < 0.001, [Formula: see text] = 0.474) by HIIT (0-min and 30-min postexercise; P < 0.091, d > 1.84) and SIT (0-min, 30-min, and 90-min postexercise; P < 0.037, d > 1.72) compared with CTRL, and SIT suppressed concentrations compared with MICT (0-min and 30-min postexercise; P < 0.91, d > 1.19). There were no effects of exercise on active PYY, active GLP-1, appetite perceptions, or free-living energy intake (P > 0.126, [Formula: see text] < 0.200). Intense interval exercise that generates lactate accumulation suppresses acylated ghrelin with little effect on anorexigenic hormones, overall appetite, or free-living energy intake.NEW & NOTEWORTHY We explored the effects of submaximal, near maximal, and supramaximal intensity exercise on appetite regulation in middle-aged adults. Our data support the intensity-dependent effect of exercise on acylated ghrelin suppression that is closely related to lactate accumulation, though there appears to be little effect on anorexigenic hormones [active peptide tyrosine tyrosine (PYY), active glucagon-like peptide-1 (GLP-1)], overall appetite, or free-living energy intake. These data support previous results in younger adults where lactate was implicated in the exercise-induced suppression of acylated ghrelin.

High-Intensity Interval Exercise with Blood Flow Restriction Improves Vascular Function in Obese Male Adolescents

Study purpose. Obesity, a chronic metabolic disease is on the rise among children and adolescents and is a leading cause of mortality in adults worldwide. It is imperative to prevent obesity in children to lower the risk of adult obesity and cardiovascular diseases. Considering the effectiveness of exercise program, high-intensity interval exercise with blood flow restriction (HIIE-BFR) may have potential beneficial effects on the vascular functions of obese individuals. This study aimed to compare the acute effects of supramaximal high-intensity interval exercise (HIIE-SUPRA) and HIIE-BFR on the vascular function in obese adolescents. Materials and methods. The subjects were adolescent males aged 13 to 15. The crossover study was divided into two trials. The first trial was a pilot study involving five obese adolescent males whose heart rates were evaluated under four conditions of exercise: 1) HIIE-SUPRA at 170% (VO₂peak), 2) HIIE-BFR at 85% VO₂peak with 40% arterial occlusion pressure (AOP), 3) 60% AOP, and 4) 80% AOP. The second trial was conducted on ten obese adolescent males who performed HIIE-SUPRA and HIIE-BFR exercises separately, each for at least three days. Data collection was done to analyze the vascular function parameters before and after exercising (immediately, 10 min, 30 min, and 60 min after). Results. The results of the first trial showed that the mean heart rate of HIIE-BFR at 40% AOP was similar to that of HIIE-SUPRA (p&gt;0.05). In the second trial, both types of exercises showed similar outcomes, with increased flow-mediated dilatation (FMD), while brachial-ankle pulse wave velocity (baPWV) decreased after exercise as compared to the baseline values (before exercise) (p&lt;0.05). However, HIIE-BFR at 40% AOP demonstrated a lower rate of perceived exertion (RPE) as compared to HIIE-SUPRA (p&lt;0.05). Conclusions. HIIE-BFR at 40% AOP was effective in regulating the RPE and acutely increasing the vascular function after exercise in obese adolescents, similar to HIIE-SUPRA.

Combined Effects of Hypocapnic Hyperventilation and Hypoxia on Exercise Performance and Metabolic Responses During the Wingate Anaerobic Test.

Hypoxia during supramaximal exercise reduces aerobic metabolism with a compensatory increase in anaerobic metabolism without affecting exercise performance. A similar response is elicited by preexercise voluntary hypocapnic hyperventilation, but it remains unclear whether hypocapnic hyperventilation and hypoxia additively reduce aerobic metabolism and increase anaerobic metabolism during supramaximal exercise. To address that issue, 12 healthy subjects (8 males and 4 females) performed the 30-second Wingate anaerobic test (WAnT) after (1)spontaneous breathing in normoxia (control, ∼21% fraction of inspired O2 [FiO2]), (2)voluntary hypocapnic hyperventilation in normoxia (hypocapnia, ∼21% FiO2), (3)spontaneous breathing in hypoxia (hypoxia, ∼11% FiO2), or (4)voluntary hypocapnic hyperventilation in hypoxia (combined, ∼11% FiO2). Mean power output during the 30-second WAnT was similar among the control (561 [133]W), hypocapnia (563 [140]W), hypoxia (558 [131]W), and combined (560 [133]W) trials (P = .778). Oxygen uptake during the 30-second WAnT was lower in the hypocapnia (1523 [318]mL/min), hypoxia (1567 [300]mL/min), and combined (1203 [318]mL/min) trials than in the control (1935 [250]mL/min) trial, and the uptake in the combined trial was lower than in the hypocapnia or hypoxia trial (all P < .001). Oxygen deficit, an index of anaerobic metabolism, was higher in the hypocapnia (38.4 [7.3]mL/kg), hypoxia (37.8 [6.8]mL/kg), and combined (40.7 [6.9]mL/kg) trials than in the control (35.0 [6.8]mL/kg) trial, and the debt was greater in the combined trial than in the hypocapnia or hypoxia trial (all P < .003). Our results suggest that voluntary hypocapnic hyperventilation and hypoxia additively reduce aerobic metabolism and increase anaerobic metabolism without affecting exercise performance during the 30-second WAnT.

Aerobic and Anaerobic Energy Contributions during Short-Duration Supramaximal Exercises with Different Exercise Intensities

The study examined the relative energy contributions during 60-s supramaximal exercise with different exercise intensities. Nine male track and field sprinters performed a 60-s Wingate anaerobic test and a 60-s cycling tests at five intensities of 55%, 65%, 75%, 85%, and 95% mean power of the Wingate anaerobic test. The relative contributions of aerobic and anaerobic energy during the 60-s cycling tests were estimated by the ratio of O2 uptake and O2 deficit, the latter being calculated as the difference between O2 demand and O2 uptake. %VO2max of the 60-s cycling tests ranged from 100 ± 7 to 163 ± 11%VO2max. As exercise intensity increased, O2 uptake, O2 deficit, and anaerobic energy contributions during the 60-s cycling tests increased (p < 0.05). In contrast, in the first ~40 s during the 60-s cycling, the anaerobic energy contributions were not significant differences between each intensity. O2 uptake per 10 s increased with time course till 40 or 50 s in each intensity (p < 0.05). The different results of these at the first ～40 and 60 s during the 60-s cycling tests could be attributed to the insufficient increase in O2 uptake during the last 20 s of the test. These results suggest that, as exercise intensity increases, the anaerobic energy contribution becomes more prominent in the latter half of the 60-s exercise (i.e., 50 and 60 s) compared to the first 30 and 40 s.

The effect of exercise hyperpnea on gross efficiency and anaerobic capacity estimates during a 3-min cycle time trial.

This study aimed to analyze the effect of exercise-induced hyperpnea on gross efficiency (GE) and anaerobic capacity estimates during a self-paced 3-min supramaximal cycle time trial (TT). Fourteen highly trained male cyclists performed 7 × 4-min submaximal stages, a 6-min passive rest, a 3-min TT, a 5-min passive rest, and a 6-min submaximal stage. Three models were based on the 7 × 4-min linear regression extrapolation method, using 1) the conventional model (7-YLIN); 2) the same 7-YLIN model but correcting for the additional ventilatory cost (i.e., hyperpnea) (7-YLIN-V-cor); and 3) accounting for linearly declining GE during the TT (7-YLIN-D). The other three models were based on GE from the last submaximal stage, using the conventional model (GELAST) and the same modifications as described for 7+YLIN, i.e., 1) GELAST, 2) GELAST-V-cor, and 3) GELAST-D. The GELAST model generated 18% higher values of anaerobic capacity than the 7-YLIN model (P < 0.05). During the TT, the hyperpnea-corrected model (i.e., 7-YLIN-V-cor or GELAST-V-cor) generated, compared with the respective conventional model (i.e., 7-YLIN or GELAST), ∼0.7 percentage points lower GE and ∼11% higher anaerobic capacity (all, P < 0.05). The post-TT GE was 1.9 percentage points lower (P < 0.001) and the 7-YLIN-D or GELAST-D model generated, compared with the respective conventional model, a lower GE (∼1.0 percentage points) and ∼17% higher anaerobic capacity during the TT (all, P < 0.05). In conclusion, the correction for a declining GE due to hyperpnea during a supramaximal TT resulted in an increased required total metabolic rate and anaerobic energy expenditure compared with the conventional models.NEW & NOTEWORTHY This study demonstrates that GE declines during a 3-min supramaximal cycle TT, which is possibly related to the hyperpneic response during supramaximal exercise. The finding from this study also provides novel insight into how the increased ventilatory energy cost from exercise-induced hyperpnea contributes to decreased GE, increased required total metabolic rate, and increased anaerobic energy expenditure during supramaximal exercise. Therefore, conventional linear models for estimating anaerobic capacity are likely to generate underestimated values.

Specific Incremental Test for Aerobic Fitness in Trail Running: IncremenTrail.

Trail running (TR) is performed in a natural environment, including various ranges of slopes where maximal oxygen consumption is a major contributor to performance. The aim of this study is to investigate the validity of tests performed in uphill conditions named the "IncremenTrail" (IncT), based on the incremental ascending speed (AS) to evaluate trail runners' cardiorespiratory parameters. IncT protocol included a constant gradient slope set at 25% during the whole test; the starting speed was 500 m·h-1 (25% slope and 2.06 km·h-1) and increased by 100 m·h-1 every minute (0.41 km·h-1). Twenty trail runner specialists performed the IncT and a supramaximal exercise bout to exhaustion with intensity set at 105% of maximal AS (Tlim). Oxygen consumption, breathing frequency, ventilation, respiratory exchange ratio (RER), and heart rate were continuously recorded during the exercises. The blood lactate concentration and rate of perceived exertion were collected at the end of the exercises. During the IncT test, 16 athletes (80%) reached a plateau of maximal oxygen uptake (65.5 ± 7.6 mL·kg-1·min-1), 19 athletes (95%) reached RER values over 1.10 (1.12 ± 0.02) and all the athletes achieved blood lactate concentration over 8.0 mmol·L-1 (17.1 ± 3.5 mmol·L-1) and a maximal heart rate ≥90% of the theoretical maximum (185 ± 11 bpm). Maximal values were not significantly different between IncT and Tlim. In addition, ventilatory thresholds could be determined for all runners with an associated AS. IncT provided a suitable protocol to evaluate trail runners' cardiorespiratory limitations and allowed us to obtain specific intensities based on the ascending speed useful for training purposes in specific conditions.

Effects of short-term repeated sprint training in hypoxia or with blood flow restriction on response to exercise

This study compared the effects of a brief repeated sprint training (RST) intervention performed with bilateral blood flow restriction (BFR) conditions in normoxia or conducted at high levels of hypoxia on response to exercise. Thirty-nine endurance-trained athletes completed six repeated sprints cycling sessions spread over 2 weeks consisting of four sets of five sprints (10-s maximal sprints with 20-s active recovery). Athletes were assigned to one of the four groups and subjected to a bilateral partial blood flow restriction (45% of arterial occlusion pressure) of the lower limbs during exercise (BFRG), during the recovery (BFRrG), exercised in a hypoxic room simulating hypoxia at FiO2 ≈ 13% (HG) or were not subjected to additional stress (CG). Peak aerobic power during an incremental test, exercise duration, maximal accumulated oxygen deficit and accumulated oxygen uptake (VO2) during a supramaximal constant-intensity test were improved thanks to RST (p < 0.05). No significant differences were observed between the groups (p > 0.05). No further effect was found on other variables including time-trial performance and parameters of the force-velocity relationship (p > 0.05). Thus, peak aerobic power, exercise duration, maximal accumulated oxygen deficit, and VO2 were improved during a supramaximal constant-intensity exercise after six RST sessions. However, combined hypoxic stress or partial BFR did not further increase peak aerobic power.

Retinal arterial occlusion following acute bout of intense exercise

The various health benefits of physical exercise are well known. Regular, moderate exercise is included in every cardiovascular risk prevention program, as it has a protective effect on the cardiac vasculature. But intense, supramaximal exercise might have potentially adverse effects ranging from increased risk of vascular endothelial injury to sudden cardiac arrest. Acute bout of exercise at high-enough intensity can damage the endothelial cells in the systemic blood vessels. Exercise also affects the retinal and choroidal blood flow, but studies evaluating these effects are limited. Autoregulation, perfusion pressure, endothelial injury, hemoconcentration, and other systemic factors play a complex role in this. In a rare occurrence, we report two cases of sudden occlusion of retinal circulation involving the central retinal artery in one and the ophthalmic artery in the other, following acute, intense exercise in otherwise young, healthy persons. Extensive investigations revealed no other cause for the occlusion. Vision in the affected eye remained poor.

P244 BRISK WALKING CAN BE A MAXIMAL EFFORT IN HEART FAILURE PATIENTS. A COMPARISON OF CARDIOPULMONARY EXERCISE AND SIX–MINUTE WALKING TEST CARDIORESPIRATORY DATA

Abstract Aims Cardiopulmonary exercise test (CPET) and six–minute walking test (6MWT) are frequently used in heart failure (HF). CPET is a maximal exercise, whereas 6MWT is a self–selected constant load test usually considered a submaximal, and therefore safer, exercise but this has not been tested previously. The aim of this study was to compare the cardiorespiratory parameters collected during CPET and 6MWT in a large group of healthy subjects and patients with HF of different severity. Methods and Results Subjects performed a standard maximal CPET and a 6MWT wearing a portable device allowing breath–by–breath measurement of cardiorespiratory parameters. HF Patients were grouped according to their CPET peak oxygen uptake (peakV̇O2). One–hundred and fifty–five subjects were enrolled, of whom 40 were healthy (59±8 years; male 67%) and 115 were HF patients (69±10 years; male 80%; left ventricular ejection fraction 34.6±12.0%). CPET peakV̇O2 was 13.5±3.5 ml/kg/min in HF patients and 28.1±7.4 ml/kg/min in healthy (p &amp;lt; 0.001). 6MWT–V̇O2 was 98±20% of the CPET peakV̇O2 values in HF patients, while 72±20% in healthy subjects (p &amp;lt; 0.001). 6MWT–V̇O2 was &amp;gt;110% of CPET peakV̇O2 in 42% of more severe HF patients (peakV̇O2&amp;lt;12ml/kg/min). Similar results have been found for ventilation and heart rate. Of note, the slope of the relationship between V̇O2 at 6MWT, reported as percentage of CPET peakV̇O2 vs. 6MWT V̇O2 reported as absolute value, progressively increased as exercise limitation did. Conclusions 6MWT must be perceived as a maximal or even supra–maximal exercise activity at least in patients with severe exercise limitation from HF. Our findings should influence the safety procedures needed for the 6MWT in HF.