Interval Training Sessions Research Articles

The Wessex Fit-4-Cancer Surgery Trial (WesFit): a protocol for a factorial-design, pragmatic randomised-controlled trial investigating the effects of a multi-modal prehabilitation programme in patients undergoing elective major intra–cavity cancer surgery

Background: Surgical resection remains the primary curative treatment for intra-cavity cancer. Low physical fitness and psychological factors such as depression are predictive of post–operative morbidity, mortality and length of hospital stay. Prolonged post-operative morbidity is associated with persistently elevated risk of premature death. We aim to investigate whether a structured, responsive exercise training programme, a psychological support programme or combined exercise and psychological support, delivered between treatment decision and major intra-cavity surgery for cancer, can reduce length of hospital stay, compared with standard care. Methods: WesFit is a pragmatic , 2x2 factorial-design, multi-centre, randomised-controlled trial, with planned recruitment of N=1560. Participants will be randomised to one of four groups. Group 1 (control) will receive usual pre-operative care, Group 2 (exercise) patients will undergo 2/3 aerobic, high-intensity interval training sessions per week supervised by personal trainers. Group 3 (psychological support) patients are offered 1 session per week at a local cancer support centre. Group 4 will receive both exercise and psychological support. All patients undergo baseline and pre-operative cardiopulmonary exercise testing, complete self-report questionnaires and will be followed up at 30 days, 12 weeks and 12 months post-operatively. Primary outcome is post-operative length-of-stay. Secondary outcomes include disability-adjusted survival at 1-year postoperatively, post-operative morbidity, and health-related quality of life. Exploratory investigations include objectively measured changes in physical fitness assessed by cardiopulmonary exercise test, disease-free and overall mortality at 1-year postoperatively, longer-term physical activity behaviour change, pre-operative radiological tumour regression, pathological tumour regression, pre and post-operative body composition analysis, health economics analysis and nutritional characterisation and its relationship to post-operative outcome. Conclusions: The WesFit trial will be a randomised controlled study investigating whether a high-intensity exercise training programme +/- psychological intervention results in improvements in clinical and patient reported outcomes in patients undergoing major inter-cavity resection of cancer. ClinicalTrials.gov registration: NCT03509428 (26/04/2018)

The effects of date seed (Phoenix dactylifera) supplementation on exercise-induced oxidative stress and aerobic and anaerobic performance following high-intensity interval training sessions: a randomised, double-blind, placebo-controlled trial.

High-intensity interval training (HIIT) is an efficient method to improve vascular function, maximal oxygen consumption, and muscle mitochondrial capacity. However, acute HIIT overstresses the oxidative system and causes muscle soreness and damage. The aim of the present study was to investigate the effects of date seeds on exercise-induced oxidative stress and aerobic and anaerobic performance following HIIT sessions. Thirty-six physically active men and women aged 18-35 years were assigned to take 26 g/d of date seed powder (DSP, n 18) or wheat bran powder (placebo, n 18) before and after HIIT workouts for 14 d. Total antioxidant capacity (TAC), oxidative stress index (OSI), total oxidant status (TOS), superoxide dismutase (SOD), glutathione peroxidase (GPx), uric acid, malondialdehyde (MDA), and 8-iso-PGF2α were determined at baseline, at the end of the intervention, and 24-h post-intervention. We used the Cooper and running-based anaerobic sprint test to assess aerobic and anaerobic performance at the study's beginning and end. Independent-samples Student's t tests, ANCOVA and repeated-measures ANOVA were used to compare the quantitative variables. Positive changes were observed in TAC, TOS, OSI, GPx, MDA and visual analogue scale after intervention and at 24-h post-exercise (P < 0·05). Likewise, peak power and fatigue index were significantly improved in DSP in comparison with the placebo group. Levels of SOD, uric acid, 8-iso-PGF2α, VO2 max and average power were not changed after training. Our results showed that date seed supplementation in active participants performing HIIT bouts ameliorated oxidative stress and improved performance parameters.

Validation of Accelerometer-Based Estimations of Energy Expenditure During High-Intensity Interval Training

Accelerometers are used to assess free-living physical activity (PA) and energy expenditure (EE). Energy expenditure estimation algorithms have been calibrated using steady-state exercise. However, most free-living PA is not steady-state. Objective: The purpose of this study was to discern the differences between criterion-measured and accelerometer-estimated EE (kCals) during a non-steady-state High-Intensity Interval Training (HIIT) session. Methods: Recreationally active adults (N=29, 18-30 years) completed one of two HIIT protocols. Each participant wore ActiGraph GT3X+ accelerometers on the right hip and non-dominant wrist while EE was measured using portable indirect calorimetry. Data analysis was conducted using custom R scripts and bias [95% CIs] to determine significant differences between indirect calorimetry and EE estimates using previously developed algorithms. Results: All accelerometer algorithms underestimated EE during recovery intervals (range; -4.31 to -6.55 kCals) and overestimated EE during work intervals (0.57 to 5.70 kcals). Over the whole HIIT session, only the Hildebrand wrist method was not significantly different from the criterion measured EE. Conclusion: Current ActiGraph EE estimations based on steady-state activities underestimate EE during recovery periods of treadmill HIIT sessions. Future studies should investigate accelerometer signals immediately after high-intensity bouts to more accurately predict EE of the subsequent recovery period. KEYWORDS: ActiGraph; Accelerometer; HIIT; Indirect calorimetry; EPOC; Energy expenditure; Non-steady state; Calories

Efficacy of Isothermic Conditioning over Military-Based Heat Acclimatization and Interval Training in Tropical Native Males.

We compared the effectiveness of three field-based training programs, namely military-based heat acclimatization (MHA), isothermic conditioning (IC) and interval training (IT), in inducing physiological adaptations in tropical natives. Fifty-one untrained tropical native males (mean ± standard deviation: age, 25 ± 2 yr; body mass index, 23.6 ± 3.2 kg·m -2 ; body fat, 19% ± 5%; 2.4-km run time, 13.2 ± 0.9 min) donned the Full Battle Order attire (22 kg) and performed a treadmill route march heat stress test in an environmental chamber (dry bulb temperature, 29.9°C ± 0.5°C; relative humidity, 70% ± 3%). Heat stress tests were conducted before (PRE) and after (POST) a 2-wk training intervention consisting of either a MHA ( n = 17, 10 sessions of military-based heat acclimatization), IC ( n = 17, 10 sessions with target gastrointestinal temperature ( Tgi ) ≥ 38.5°C) or IT ( n = 17, six sessions of high-intensity interval training) program. Tgi , HR, mean weighted skin temperature ( Tsk ), physiological strain index (PSI) and thigh-predicted sweat sodium concentration ([Na + ]) were measured and analyzed by one-factor and two-factor mixed design ANOVA with a 0.05 level of significance. Field-based IC induced a greater thermal stimulus than MHA ( P = 0.029) and IT ( P < 0.001) during training. Reductions in mean exercise Tgi (-0.2°C [-0.3°C, 0.0°C]; P = 0.009) , PSI (-0.4 [-0.7, -0.1]; P = 0.015) and thigh-predicted sweat [Na + ] (-9 [-13, -5 mmol·L -1 ]; P < 0.001) were observed in IC but not MHA and IT (all P > 0.05). Resting HR (MHA, -4 bpm [-7, 0 bpm]; P = 0.025; IC, -7 bpm [-10, -4 bpm]; P < 0.001; IT, -4 bpm [-8, -1 bpm]; P = 0.008) and mean exercise HR (MHA, -4 [-8, 0 bpm]; P = 0.034; IC, -11 bpm [-15, -8 bpm]; P < 0.001, IT = -5 bpm [-9, -1 bpm]; P = 0.012) were lowered in all groups after training. Isothermic conditioning elicited a greater attenuation in mean exercise HR and thigh-predicted sweat [Na + ] relative to MHA (both P < 0.05). No between-group differences were observed when comparing MHA and IT (all P > 0.05). Isothermic conditioning induced a more complete heat-adapted phenotype relative to MHA and IT. Interval training may serve as a time efficient alternative to MHA.

Transient speeding of V̇O2 kinetics following acute sessions of sprint interval training: Similar exercise dose but different outcomes in older and young adults

An acute session of sprint interval training (SIT) is a potent stimulus for the metabolic and cardiovascular systems. However, the feasibility of SIT in older adults and its effectiveness to acutely improve aerobic function by transiently accelerating the rate of adjustment of oxidative phosphorylation quantified by V̇O2 kinetics (τV̇O2) are unknown. This study evaluated the time course of changes of τV̇O2 in response to different doses of SIT in older inactive adults compared to their young counterparts. Eight older (age: 67±3years) and eight young (age: 30±3years) adults completed three separate SIT sessions consisting of either one (SIT1), three (SIT3), or five (SIT5) consecutive bouts of SIT. Each SIT intervention was interspersed by a two-week recovery phase. The bike resistance during the sprints was set at 0.065kg·kg-1 body mass for older and 0.075kg·kg-1 body mass for young adults. Moderate-intensity step-transitions were performed to assess τV̇O2 before (PRE) and one (1d), two (2d) and three (3d) days post each SIT intervention. Older adults attained lower peak power outputs, average power output, and blood lactate concentrations across all sprints of each SIT intervention compared to young (P<0.01). Following SIT1, τV̇O2 was faster at 1d (-13.6%; P=0.008) and 2d (-12.7%; P=0.017) and returned to values similar to PRE at 3d (+0.4%; P>0.05) in both older and young. Following SIT3, τV̇O2 was faster at 1d (-20.6%; P<0.001), 2d (-18.5%; P=0.011), and 3d (-14.5%; P=0.045) compared to PRE in both older and young. Following SIT5, τV̇O2 became faster in older (at 1d, 2d, and 3d; ~25%; P<0.05) but remained unchanged in young with respect to PRE (P>0.05). These findings indicate that SIT has the potency to acutely improve aerobic function by speeding the rate of adjustment of oxidative phosphorylation. However, only older adults were able to maintain these beneficial effects when the volume of SIT was maximized (SIT5). Future studies are warranted to evaluate the long-term feasibility of SIT in older adults.

Gait and Neuromuscular Changes Are Evident in Some Masters Club Level Runners 24-h After Interval Training Run.

PurposeTo examine the time course of recovery for gait and neuromuscular function immediately after and 24-h post interval training. In addition, this study compared the impact of different statistical approaches on detecting changes.MethodsTwenty (10F, 10M) healthy, recreational club runners performed a high-intensity interval training (HIIT) session consisting of six repetitions of 800 m. A 6-min medium intensity run was performed pre, post, and 24-h post HIIT to assess hip and knee kinematics and coordination variability. Voluntary activation and twitch force of the quadriceps, along with maximum isometric force were examined pre, post, and 24-h post significance HIIT. The time course of changes were examined using two different statistical approaches: traditional null hypothesis significance tests and “real” changes using minimum detectable change.ResultsImmediately following the run, there were significant (P < 0.05) increases in the hip frontal kinematics and coordination variability. The runners also experienced a loss of muscular strength and neuromuscular function immediately post HIIT (P < 0.05). Individual assessment, however, showed that not all runners experienced fatigue effects immediately post HIIT. Null hypothesis significance testing revealed a lack of recovery in hip frontal kinematics, coordination variability, muscle strength, and neuromuscular function at 24-h post, however, the use of minimum detectable change suggested that most runners had recovered.ConclusionHigh intensity interval training resulted in altered running kinematics along with central and peripheral decrements in neuromuscular function. Most runners had recovered within 24-h, although a minority still exhibited signs of fatigue. The runners that were not able to recover prior to their run at 24-h were identified to be at an increased risk of running-related injury.

Training Periodization, Methods, Intensity Distribution, and Volume in Highly Trained and Elite Distance Runners: A Systematic Review.

This review aimed to determine (1)performance and training characteristics such as training intensity distribution (TID), volume, periodization, and methods in highly trained/elite distance runners and (2)differences in training volume and TID between event distances in highly trained/elite distance runners. A systematic review of the literature was carried out using the PubMed/MEDLINE, Scopus, and Web of Science databases. Ten articles met the inclusion criteria. Highly trained/elite distance runners typically follow a pyramidal TID approach, characterized by a decreasing training volume from zone 1 (at or below speed at first ventilatory/lactate threshold [LT]) to zone 2 (between speeds associated with either both ventilatory thresholds or 2 and 4 mmol·L-1 LTs [vLT1 and vLT2, respectively]) and zone 3 (speed above vVT2/vLT2). Continuous-tempo runs or interval training sessions at vLT2 in zone 2 (ie,medium and long aerobic intervals) and those in zone 3 (ie,anaerobic or short-interval training) were both used at least once per week each in elite runners, and they were used to increase the number of either vLT2 or z3 sessions to adopt either a pyramidal or a polarized approach, respectively. More pyramidal- and polarized-oriented approaches were used by marathoners and 1500-m runners, respectively. Highly trained and elite middle- and long-distance runners are encouraged to adopt a traditional periodization pattern with a hard day-easy day basis, consisting in a shift from a pyramidal TID used during the preparatory and precompetitive periods toward a polarized TID during the competitive period.

Three hours of Moderate Intensity Exercise Training Reduces Glucose Tolerance in Endurance Trained Athletes

Objectives:It is well accepted that exercise training improves glucose uptake and insulin sensitivity, and that endurance trained athletes in general show a high capacity for these parameters. However, some studies have observed negative effects on glucose regulation in healthy, trained subjects the day after exercise. These, often unexpected, results have been postulated to be caused by excessive training loads, muscle damage, energy deficit, differences in glucose uptake in the exercised and non-exercised musculature and a metabolic interaction through increased fatty acid metabolism. The mode or volume of exercise that can lead to glucose intolerance in trained athletes as well as its relevance for health and performance are, however, not fully understood. We here studied the metabolic response to a glucose load the day after a session of high intensity interval training (HIIT) or three hours of continuous exercise (3h) in endurance trained athletes and compared the results with measurements during rest.Methods:Nine endurance trained athletes underwent oral glucose tolerance tests (OGTT) after rest and ˜14 hours after exercise on a cycle ergometer (HIIT 5x4 minutes at ˜95% of VO2max or 3h at 65% of VO2max). Concentrations of glucose, insulin, free fatty acids (FFA) and ketones (β-hydroxybutyrate) were measured. Statistical analysis was performed using a RM one-way ANOVA.Results:The area under the curve (AUC) during the OGTT increased greatly after 3h (668±124 mM · min) (p<0.01) compared to rest (532±89) but was found to be unchanged after HIIT (541±96). Resting values of FFA and ketones were increased after 3h (p<0.01 and p<0.05, respectively) but not after HIIT. Insulin was found to be unaltered during all conditions.Conclusion:Here, we show manifestation of glucose intolerance in endurance trained athletes together with concomitant increases in plasma concentrations of FFA and ketones the day after a session of prolonged exercise training but not after HIIT. This could be a protective response for securing glucose delivery to the brain and therefore have a positive effect on endurance. It also has the potential to reduce the recovery of glycogen depots, glucose uptake during exercise and performance at higher work rates.

Preconditioning Activities to Enhance Repeated High-Intensity Efforts in Elite Rugby Union Players.

To assess the effect of a rugby-specific high-intensity interval-training (HIITRugby) protocol on the repeated high-intensity-effort ability of young elite rugby union players and to verify the influence of 2 preconditioning sequences composed either of physical contacts (ie,tackles) or of additional runs on the magnitude of improvement. Fourteen players (19 [1]y; 183.5 [8.6]cm; 95.6 [15.6]kg) underwent an HIITRugby protocol, consisting of 7 supervised training sessions over 4weeks, each session including 3 or 4 sets of 1 to 2minutes with 1-minute recovery. Prior to HIITRugby training, players underwent a preconditioning contact sequence or a preconditioning running sequence, to assess their influence on subsequent interval-training sessions. The overall group showed a moderate improvement in total sprint time, sprints ≥90% of the best, and 20-m sprint (-3.91% [2.68%], P = .0002; 74.6% [123.7%], P = .012; -3.22% [3.13%], P = .003, respectively) and a large improvement in percentage decrement (-23.1% [20.5%], P = .005) following the 4-week training block. Relative improvements were similar between groups in total sprint time, 20-m sprint, and perceived difficulty, but the preconditioning running-sequence group exhibited a larger magnitude of gains in percentage decrement (-28.6% [20.2%] vs -17.6% [20.7%]; effect size = -1.01 vs -0.73). An HIITRugby training block was effective to improve repeated high-intensity-effort ability. A preconditioning contact sequence prior to HIITRugby can reduce subsequent long-interval running activity, which may attenuate the improvement of repeated high-intensity-effort indices related to the aerobic system.

Effects of Interval Training Under Hypoxia on Hematological Parameters, Hemodynamic Function, and Endurance Exercise Performance in Amateur Female Runners in Korea.

Interval training under hypoxia (IHT) is commonly used to enhance endurance exercise performance. However, previous studies examining hematologic changes related to the immune system that affect health and conditioning are lacking. This study aimed to evaluate the effects of IHT for 6-weeks on hematological parameters, hemodynamic function, and endurance exercise performance in amateur Korean female runners. Twenty healthy amateur Korean female runners (age: 24.85 ± 3.84 years) were equally assigned to normoxic training group (NTG) for interval training under normoxia (760 mmHg) and hypoxic training group (HTG) for interval training under hypobaric hypoxia (526 mmHg, 3000 m simulated altitude) according to their body composition and endurance exercise performance. All participants performed 120-min of training sessions, consisting of 20-min of warm-up, 60-min of interval training, and 20-min of cool-down. The training program was performed 3-days per week for 6-weeks. Warm-up and cool-down were performed for 20-min at 60% maximal heart rate (HRmax). The interval training sessions comprised 10 repetitions of interval exercise (5-min of exercise corresponding to 90–95% HRmax and 1-min of rest) on a treadmill. All participants underwent measurements of hematological parameters, hemodynamic function, and endurance exercise performance before and after training. Both groups showed a significant increase in erythropoietin (EPO) level and a decrease in monocyte abundance, with EPO showing a greater increase in the HTG than in the NTG. B cell abundance significantly increased in the NTG; hematocrit and neutrophil counts significantly increased, and lymphocyte counts significantly decreased in the HTG. The HTG showed a significant improvement in oxygen uptake, stroke volume index, and end-diastolic volume index compared to the NTG. In addition, both groups showed significant improvements in heart rate, end-systolic volume index, and cardiac output index. The maximal oxygen uptake and 3000 m time trial record were significantly improved in both groups, and the HTG showed a tendency to improve more than the NTG. In conclusion, the IHT was effective in enhancing endurance exercise performance through improved hemodynamic function. Furthermore, hematological parameters of immune system showed a normal range before and after training and were not negatively affected.

Acute effects of high intensity training on cardiac function: a pilot study comparing subjects with type 2 diabetes to healthy controls

This study evaluated acute cardiac stress after a high-intensity interval training session in patients with type 2 diabetes (T2D) versus healthy controls. High intensity aerobic exercise was performed by 4 × 4-min intervals (90–95% of maximal heart rate), followed by a ramp protocol to peak oxygen uptake. Echocardiography was performed before and 30 min after exercise. Holter electrocardiography monitored heart rhythms 24 h before, during, and 24 h after the exercise. Left atrial end-systolic volume, peak early diastolic mitral annular velocity, and the ratio of peak early to late diastolic mitral inflow velocity were reduced by approximately 18%, 15%, and 31%, respectively, after exercise across groups. Left ventricular end-diastolic wall thickness was the only echo parameter that significantly differed between groups in response to exercise. The T2D group had a rate of supraventricular extrasystoles per hour that was 265% greater than that of the controls before exercise, which remained higher after exercise. A single exhaustive exercise session impaired left ventricular diastolic function in both groups. The findings also indicated impaired right ventricular function in patients with T2D after exercise.ClinicalTrials.gov Identifier: NCT02998008.

Concurrent Training Programming: The Acute Effects of Sprint Interval Exercise on the Subsequent Strength Training.

Exercise modality has been proposed to reduce the interferences between aerobic and resistance sessions during concurrent training. The aim of the study was to examine the acute effects of cycling or running sprint interval exercise on subsequent resistance training sessions. Twenty-five competitive male rugby union players were recruited. Players were tested during three conditions: CONTROL (resistance training session only), CYCLE and RUN (corresponding to a concurrent training scheme with cycling or running sprint interval exercise conducted on the morning, followed by a resistance training session). Four hours rest was proposed between the aerobic and resistance training session. Muscle performance (bar velocity during bench press and box squat, counter movement jump height) and subjective ratings (rate of perceived exertion, wellbeing) were assessed during and after aerobic or resistance training sessions. No significant difference was observed for muscle performance (vertical jump height and bar velocity). However, significant higher perceived exertion and low-value scaled subjective wellbeing were observed in RUN (7.7 ± 1.1 and 17.9 ± 4.1, respectively) as compared with the two other conditions (6.7 ± 1.5 and 21.1 ± 3.6 for CONTROL and 7.4 ± 1.1 and 20.1 ± 3.9 for CYCLE). It was concluded that the exercise modality (running or cycling) during the aerobic exercise using a sprint interval exercise did not impact the quality of the resistance session. However, subjective ratings were affected the following days. Cycling exercises might be more adequate when performing a sprint interval training session during concurrent training programs.

The Salzburg 10/7 HIIT shock cycle study: the effects of a 7-day high-intensity interval training shock microcycle with or without additional low-intensity training on endurance performance, well-being, stress and recovery in endurance trained athletes—study protocol of a randomized controlled trial

BackgroundPerforming multiple high-intensity interval training (HIIT) sessions in a compressed period of time (approximately 7–14 days) is called a HIIT shock microcycle (SM) and promises a rapid increase in endurance performance. However, the efficacy of HIIT-SM, as well as knowledge about optimal training volumes during a SM in the endurance-trained population have not been adequately investigated. This study aims to examine the effects of two different types of HIIT-SM (with or without additional low-intensity training (LIT)) compared to a control group (CG) on key endurance performance variables. Moreover, participants are closely monitored for stress, fatigue, recovery, and sleep before, during and after the intervention using innovative biomarkers, questionnaires, and wearable devices.MethodsThis is a study protocol of a randomized controlled trial that includes the results of a pilot participant. Thirty-six endurance trained athletes will be recruited and randomly assigned to either a HIIT-SM (HSM) group, HIIT-SM with additional LIT (HSM + LIT) group or a CG. All participants will be monitored before (9 days), during (7 days), and after (14 days) a 7-day intervention, for a total of 30 days. Participants in both intervention groups will complete 10 HIIT sessions over 7 consecutive days, with an additional 30 min of LIT in the HSM + LIT group. HIIT sessions consist of aerobic HIIT, i.e., 5 × 4 min at 90–95% of maximal heart rate interspersed by recovery periods of 2.5 min. To determine the effects of the intervention, physiological exercise testing, and a 5 km time trial will be conducted before and after the intervention. ResultsThe feasibility study indicates good adherence and performance improvement of the pilot participant. Load monitoring tools, i.e., biomarkers and questionnaires showed increased values during the intervention period, indicating sensitive variables.ConclusionThis study will be the first to examine the effects of different total training volumes of HIIT-SM, especially the combination of LIT and HIIT in the HSM + LIT group. In addition, different assessments to monitor the athletes' load during such an exhaustive training period will allow the identification of load monitoring tools such as innovative biomarkers, questionnaires, and wearable technology. Trial Registration: clinicaltrials.gov, NCT05067426. Registered 05 October 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05067426. Protocol Version Issue date: 1 Dec 2021. Original protocol. Authors: TLS, NH.

Concurrent Validity of a Continuous Glucose-Monitoring System at Rest and During and Following a High-Intensity Interval Training Session.

To assess the concurrent validity of a continuous blood-glucose-monitoring system (CGM) postbreakfast, preexercise, exercise, and postexercise, while assessing the impact of 2 different breakfasts on the observed level of validity. Eight nondiabetic recreational athletes (age = 30.8 [9.5]y; height = 173.6 [6.6]cm; body mass = 70.3 [8.1]kg) took part in the study. Blood glucose concentration was monitored every 10 minutes using both a CGM (FreeStyle Libre, Abbott, France) and finger-prick blood glucose measurements (FreeStyle Optimum) over 4 different periods (postbreakfast, preexercise, exercise, and postexercise). Two different breakfasts (carbohydrates [CHO] and protein oriented) over 2 days (2 × 2 d in total) were used. Statistical analyses included the Bland-Altman method, standardized mean bias (expressed in standardized units), median absolute relative difference, and the Clarke error grid analysis. Overall, mean bias was trivial to small at postbreakfast (effect size ± 90% confidence limits: -0.12 ± 0.08), preexercise (-0.08 ± 0.08), and postexercise (0.25 ± 0.14), while moderate during exercise (0.66 ± 0.09). A higher median absolute relative difference was observed during exercise (13.6% vs 7%-9.5% for the other conditions). While there was no effect of the breakfast type on the median absolute relative difference results, error grid analysis revealed a higher value in zone D (ie,clinically unsafe zone) during exercise for CHO (10.5%) compared with protein (1.6%). The CGM device examined in this study can only be validly used at rest, after both a CHO and protein-rich breakfast. Using CGM to monitor blood glucose concentration during exercise is not recommended. Moreover, the accuracy decreased when CHO were consumed before exercise.

Low-Volume High-Intensity Interval Training Sessions With Different Work–Recovery Durations and Muscle Damage in Trained Men

ABSTRACT Purpose: This study compared the effect of low-volume high-intensity training (LV-HIIT) sessions with different work-recovery durations on muscle damage markers.Methods: Twenty-four trained adult males (22.3 ± 2.9 years; 24.6 ± 2.7 kg∙m-2) performed two LV-HIIT sessions (10 x 60 s and 20 x 30 s at 100% of maximal aerobic speed on treadmill (Vmax) interspersed with equal time passive recovery, respectively) in a randomized, counter-balanced order, separated by a 1-week interval. Delayed onset muscle soreness (DOMS) and countermovement vertical jump height (CVJH) performance were assessed before, and 24-h and 48-h post sessions.Results: Pressure-pain threshold (PPT), pressure-pain tolerance (PPTol) and perceived pain intensity (PPI) using pressure algometry assessed DOMS in the rectus rectus femoris, biceps femoris and gastroctemius. A non-significant session by time interaction for PPT, PPTol and PPI in all muscles analyzed was observed (all P > 0.260). Additionally, a non-significant session by time interaction was observed for CVJH performance (P = 0.836).Conclusion: LV-HIIT sessions with different work-recovery durations elicited non-significant changes on muscle damage markers following 24- and 48-h in trained males.

Active vs. passive recovery during an aerobic interval training session in well-trained runners

PurposeTo compare cardio-metabolic, perceptual and neuromuscular responses to an aerobic interval training (AIT) running session, with active (AR) vs. passive recovery (PR).MethodsEleven well-trained male distance runners (36.63 ± 6.93 years, 59.26 ± 5.27 mL·kg−1·min−1, ⁓ 35 min in 10 km) completed the University of Montréal Track Test (UMTT) and 2 AIT sessions on track in random order, which consisted of 4 × 2 min at 100% of the maximum aerobic speed (MAS), with 2 min of AR at 80% of the velocity associated to the second ventilatory threshold (vVT2), or no exercise (i.e., PR). During sessions, oxygen consumption (V̇O2), heart rate (HR), blood lactate [La], rating of perceived exertion (RPE), and countermovement jump (CMJ) were continuously monitored.ResultsThere were no differences in time spent in the “red zone” (i.e. > 90% V̇O2max) between sessions (222 ± 73 s AR vs. 230 ± 104 s PR, p = 0.588), although the PR exhibited a greater time spent at peak V̇O2 close to significance (117 ± 114 vs. 158 ± 109 s, p = 0.056). However, the AR elicited a higher mean V̇O2 (49.62 ± 5.91 vs. 47.46 ± 4.20 mL·kg−1·min−1, p = 0.021). The AR favored a lower [La] after sessions (6.93 ± 2.22 vs. 6.24 ± 1.93 mmol·L−1, p = 0.016) and a higher RPE during sessions (15 ± 0.45 vs. 14 ± 0.47, p = 0.045). Meanwhile, the CMJ was significantly potentiated during both sessions.ConclusionConsidering that PR elicited lower perceptual loading for a similar cardiorespiratory response, its use would be preferable, at least, for this type of AIT running sessions.

The Science of Handcycling: A Narrative Review.

The aim of this narrative review is to provide insight as to the history, biomechanics, and physiological characteristics of competitive handcycling. Furthermore, based upon the limited evidence available, this paper aims to provide practical training suggestions by which to develop competitive handcycling performance. Handbike configuration, individual physiological characteristics, and training history all play a significant role in determining competitive handcycling performance. Optimal handcycling technique is highly dependent upon handbike configuration. As such, seat positioning, crank height, crank fore-aft position, crank length, and handgrip position must all be individually configured. In regard to physiological determinants, power output at a fixed blood lactate concentration of 4mmol·L-1, relative oxygen consumption, peak aerobic power output, relative upper body strength, and maximal anaerobic power output have all been demonstrated to impact upon handcycling performance capabilities. Therefore, it is suggested that that an emphasis be placed upon the development and frequent monitoring of these parameters. Finally, linked to handcycling training, it is suggested that handcyclists should consider adopting a concurrent strength and endurance training approach, based upon a block periodization model that employs a mixture of endurance, threshold, interval, and strength training sessions. Despite our findings, it is clear that several gaps in our scientific knowledge of handcycling remain and that further research is necessary in order to improve our understanding of factors that determine optimal performance of competitive handcyclists. Finally, further longitudinal research is required across all classifications to study the effects of different training programs upon handcycling performance.

Analysis of the neuromuscular responses during two different high- intensity interval training sessions in athletes of cyclic and acyclic sports

Analysis of the neuromuscular responses during two different high- intensity interval training sessions in athletes of cyclic and acyclic sports

High-intensity interval training versus moderate-intensity continuous training on cardiac autonomic control in hypertensive patients

Aim: This study aims to verify and compare the acute and chronic effects of high-intensity interval training and moderate-intensity continuous training sessions on the linear and nonlinear heart rate variability indexes, responses of blood pressure, aerobic power, aerobic capacity, and quality of life from patients with systemic arterial hypertension. Methods: Controlled, randomized clinical trial with intention-to-treat analysis. Non-alcoholic, non-diabetic patients between 18 and 60 years of age, with a diagnosis of prehypertension or stage I hypertension for at least 12 months and with controlled blood pressure levels. Conclusion: This protocol study intends to show that high-intensity interval exercise in controlled hypertensive patients with low cardiovascular risk has a greater hypotensive effect, as well as an increase in vagal modulation on the heart.

Effects of Interval Training Under Hypoxia on the Autonomic Nervous System and Arterial and Hemorheological Function in Healthy Women.

PurposeThe present study verified the effects of interval training under hypoxia, a novel exercise modality for health promotion, on the autonomic nervous system (ANS) and arterial and hemorheological function in healthy women.MethodsTwenty healthy Korean women (age: 19–29 [24.85 ± 3.84] years) were equally assigned to interval normoxic training (INT, n = 10; residing and training under normoxia) and interval hypoxic training (IHT, n = 10; residing under normoxia and training under 526 mmHg hypobaric hypoxia) groups. All participants performed 90-min of training sessions composed of 15-min of warm-up, 60-min of interval training, and 15-min of cool-down. The interval training sessions composed of 10 repetitions of interval exercise using a treadmill (5 min of exercise corresponding to 90–95% maximal heart rate [HR] and 1 min of rest). The training was performed 3 days per week for 6 weeks. All participants underwent body composition, HR variability, brachial-ankle pulse wave velocity, flow-mediated dilation (FMD), red blood cell (RBC) deformability and aggregation, and maximal oxygen uptake (VO2max) measurements before and after training.ResultsThere were no significant differences in body composition between the groups. The IHT group showed a significant improvement in the ANS function (root mean square of successive differences, high frequency, and low frequency/high frequency ratio), arterial stiffness, arterial endothelial function (FMD), hemorheological function (RBC deformability and aggregation), and aerobic performance (VO2max) compared with the INT (all p < 0.05).ConclusionIn comparison with the interval training under normoxia, the interval training under hypoxia is a novel and effective exercise modality for promoting aerobic performance with the ANS and arterial and hemorheological function in healthy women.