Determinants of Elite Rowing Performance: Implications for Developing Rowers

To evaluate the effect of increasing the maximal oxygen uptake ((Equation is included in full-text article.)O2max) and the safety of maximal-intensity aerobic interval training (MAIT) compared with high-intensity aerobic interval training (HAIT). Forty-seven patients with first-ever acute coronary syndrome were assigned to MAIT or HAIT. Subjects underwent adaptation period during the first 2 wk of cardiac rehabilitation and then MAIT at 95-100% of the heart rate reserve or HAIT at 85% of the heart rate reserve, 3 d/wk for 4 wk. The primary outcome was (Equation is included in full-text article.)O2max. The secondary outcomes were major cardiovascular complications, hemodynamic responses, myocardial oxygen demand, cardiometabolic health, and echocardiographic findings. A total of 670.5 hr of MAIT and HAIT were completed. After 6 wk of aerobic interval training, (Equation is included in full-text article.)O2max was significantly increased in both groups. However, the increment of (Equation is included in full-text article.)O2max was significantly greater in the MAIT group than in the HAIT group (P < .05). The percentage increases for MAIT and HAIT were 31% and 17%, respectively. No major cardiovascular or musculoskeletal complications were noted. The results of this study indicate that 6 wk of MAIT resulted in statistically significantly better improvement in (Equation is included in full-text article.)O2max than 6 wk of HAIT at a similar total work in patients with acute coronary syndrome. Moreover, both MAIT and HAIT may be safe to use in the cardiac rehabilitation setting.

BackgroundThere is limited knowledge about atrial myocyte Ca2+ handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca2+ handling in rats with post-infarction heart failure (HF) and to examine whether aerobic interval training could reverse a potential dysfunction.Methods and resultsPost-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p<0.01) and time to relaxation was prolonged (p<0.01) in sedentary HF-rats compared to healthy controls. This was associated with decreased Ca2+ amplitude, decreased SR Ca2+ content, and slower Ca2+ transient decay. Atrial myocytes from HF-rats had reduced sarcoplasmic reticulum Ca2+ ATPase activity, increased Na+/Ca2+-exchanger activity and increased diastolic Ca2+ leak through ryanodine receptors. High intensity aerobic interval training in HF-rats restored atrial myocyte contractile function and reversed changes in atrial Ca2+ handling in HF.ConclusionPost infarction HF in rats causes profound impairment in atrial myocyte contractile function and Ca2+ handling. The observed dysfunction in atrial myocytes was partly reversed after aerobic interval training.

Everett, KLA, Chapman, DW, Mitchell, JA, and Ball, N. Changes in loaded countermovement jumps during precompetition and competition training mesocycles in elite rowers. J Strength Cond Res 36(9): 2622-2627, 2022-To assess changes in velocity, displacement, and power as an indicator of neuromuscular fatigue (NMF) within and between precompetition and competition mesocycles in elite male rowers using loaded countermovement jumps (CMJs). Twenty highly trained rowers completed regular training (on-water rowing, rowing ergometer, and resistance training sessions) in 2 consecutive mesocycles. Athletes completed a single set of 6 loaded (20 kg) CMJs in the first and final week of each mesocycle. Countermovement jumps were assessed for jump height (JH), eccentric displacement, mean velocity (MV), eccentric MV (EMV), and mean power. Changes between time points were reported as Cohen's d effect sizes (95% confidence interval [CI]). The magnitude of the differences was also considered based on their relative strength levels using a linear mixed model. Within the precompetition mesocycle, trivial-to-small reductions for all variables (0.5-4.1%) were observed. During the competition mesocycle, trivial-to-small increases were shown for EMV (1.4%) and eccentric displacement (2.0%) with no change in JH and small reductions in MV (0.5%) and mean power (2.8%). No differences between the precompetition and competition mesocycles were shown. Only mean power showed a significant reduction in weaker athletes (3.2%) compared with stronger athletes (2.3%). Training completed during a precompetition and competitive mesocycle did not result in significant decreases in athlete's loaded CMJ performance, indicating that NMF was minimized. Alternatively, use of a loaded CMJ may not be sensitive enough to observe NMF in elite rowers during the mesocycle immediately leading into and during a competition mesocycle.

Cycle training is an important training modality of elite rowers. Cycling is the preferred alternative to on-water and ergometer rowing as it provides a reduction in compressive forces on the thoracic cage and upper extremities while still creating a local and central acclimation to endurance training. It is hypothesised, however, that there will be differences in physiological characteristics between Concept II (CII) rowing and WattBike (WB) cycling due to the principle regarding the specificity of training that elite rowers undertake. Understanding these differences will ensure more accurate training prescription when cycling. Twenty international level male rowers, [O2PEAK 5.85 ± 0.58 L.min−1 (CI ± 0.26 L.min−1)] participated in two identical discontinuous incremental exercise tests on a CII rowing and WB cycle ergometer. Ergometer modalities were randomised and counterbalanced among the group and tests occurred 7 days apart. O2, CO2, E(STPD) and HR were significantly higher for every submaximal power output on the CII compared with the WB. Maximal power output on the WB was higher than on the CII [42 ± 33 W (CI ± 14 W) p < 0.000] but O2PEAK was similar between modalities. Minute ventilation at maximal exercise was 11 L.min−1 lower on CII than on WB. When data were expressed relative to modality specific O2PEAK, power output was consistently lower on the CII as was submaximal CO2, RER, RPE, mechanical efficiency and BLa concentration at 75% O2PEAK. Across all power outputs and exercise modalities, 77% of the variance in RPE could be explained by the variance in BLa. These results demonstrate that elite rowers can attain similar O2PEAK scores regardless of modality. Substantial physiological and metabolic differences are evident between CII rowing and WB cycling when power output is the independent variable with the latter being over 40 W higher. The difference in displayed power output between the ergometer modalities is attributed to differences in mechanical efficiency and a degree of power output not being accounted for on the CII ergometer. Given the lack of consistency between CII and WB power output, other physiological measures, such as HR, are better suited to prescribe WB ergometer sessions.

PURPOSE: To evaluate the metabolic and cardiovascular response during four different high intensity aerobic interval training (HIT) protocols with similar total work output. METHODS: Eight young physically active subjects participated in five different bouts of exercise over a 3-wk period, where VO2 and HR were continuously monitored. Protocol one consisted of 20 min continuous exercise at ∼70% of VO2max. Protocols 2, 3, 4, and 5 were interval based with a work:active rest period (in seconds) of 30:30, 60:30, 90:30, and 60:60 respectively. Each interval protocol was at a workload corresponding to 90% VO2max as determined by a maximal graded exercise test, and each resulted in ∼10 minutes of work but differed in the rest duration. Active rest was carried out at a workload corresponding to ∼35-40% VO2max. RESULTS: The 90:30 HIT protocol resulted in the highest VO2, HR, RPE, and blood lactate whereas the 30:30 protocol resulted in the lowest of these parameters (P < 0.05). The total caloric energy expenditure was lowest in the 90:30 and 60:30 protocol (∼150kcal) (P < 0.05), whereas the other 3 protocols averaged ∼200 kcal. The immediate post-exercise blood pressure was similar across all protocols. CONCLUSIONS: These finding indicate that varying the work-to-rest ratio affects the metabolic response to HIT, and that HIT performed at 90% of VO2max is physiologically feasible and may be used as an alternative approach to training middle-aged subjects, but with less time commitment.

High-intensity work might not be preserved in chronic obstructive pulmonary disease (COPD) during whole-body exercise due to ventilatory limitations that exceed metabolic limitations, resulting in reduced training adaptations. The purpose of the present study was to address the hyperoxic effect during training and testing in COPD patients with hypoxemia at peak exercise. Six COPD and eight coronary artery disease (CAD) patients completed 24 aerobic high-intensity interval training sessions, 4x4 min in hyperoxia at 85-95% of the peak heart rate and peak exercise tested in normoxia and hyperoxia pre- and post-training. VO2peak increased in the COPD group by 19% (13-31%) and in the CAD group by 15% (7-29%), [0.98(0.68-1.52)-1.17(0.89-1.78) and 2.11(1.57-2.64)-2.44(1.92-3.39) L/min], respectively. VO2peak was higher in hyperoxia at pre- and post-test (1.22(0.80-1.87) and 1.37(1.01-1.94) L/min) in the COPD group. Work economy improved by 10% in both groups. Quality of life improved in the COPD group in terms of physical and mental health status by 24% and 35%. Hyperoxic aerobic high-intensity interval training in COPD patients with hypoxemia at peak exercise increases VO2peak, peak workload, work economy and quality of life. Acute hyperoxia increases VO2peak, peak workload at pre- and post-test compared with normoxia in the COPD patients, indicating an oxygen supply limitation to VO2peak.

Aerobic interval training preconditioning protocols inhibit isoproterenol-induced pathological cardiac remodeling in rats: Implications on oxidative balance, autophagy, and apoptosis

Aim. The aim of our study was to conduct a comparative analysis of aerobic high-intensity interval training and constant moderate intensity training in cardiac rehabilitation of adult patients after open-heart surgery, namely after coronary artery bypass grafting (CABG). Material and methods. 137 patients after CABG were included in the study. 90.4% of patients were consider as class I of chronic heart failure after surgery. Cardiorespiratory trainings were initiate in 4 weeks after surgery, using cycling by veloergometers. Two groups were compare according to rehabilitation programs: one carried out constant aerobic trainings of moderate and medium intensity, and the other, aerobic high-intensity interval trainings. Supervised trainings were carry out for 150 minutes per week. Total length of trainings was 47 weeks. Long-term trainings were distantly monitore. Results. Ergospirometric results as well as results of echocardiography were significantly improve after training course. These results were more significant in high-intensity interval training group, compared to moderate intensity-training group. VO2, heart rate and training power significantly improved. Body mass index significantly diminished in high-intensity interval training group, compared to moderate intensity-training group. In 7 weeks after training ominously decreased blood triglycerides and increased high-density lipoproteins. Conclusion. Cardiorespiratory trainings ameliorate mitochondrial biogenesis, carbohydrate and lipid metabolism, promote to reduce abdominal obesity and other crucial risk factors of coronary patients. Aerobic high-intensity interval cardiac trainings are as safe as moderate intensity cardiac trainings, and in some issues, they outperform moderate intensity cardiac trainings.

Previous studies have explored the effect of differing heat and relative humidity (RH) environments on the performance of multiple anaerobic high-intensity interval training (HIIT). Still, its impact on physiological responses and performance following aerobic HIIT has not been well studied. This study examined the effects of differing RH environments on physiological responses and performance in college football players following HIIT. Twelve college football completed HIIT under four different environmental conditions: (1) 25 °C/20% RH (Control group); (2) 35 °C/20% RH (H20 group); (3) 35 °C/40% RH (H40 group); (4) 35 °C/80% RH (H80 group). The heart rate (HR), mean arterial pressure (MAP), lactate, tympanic temperature (TT), skin temperature (TS), thermal sensation (TS), and rating of perceived exertion (RPE) were recorded continuously throughout the exercise. The heart rate variability (HRV): including root mean squared differences of the standard deviation (RMSSD)、standard deviation differences of the standard deviation (SDNN)、high frequency (HF), low frequency (LF), squat jump height (SJH), cycling time to exhaustion (TTE), and sweat rate (SR) were monitored pre-exercise and post-exercise. The HR, MAP, lactate, TT, Ts, TS, and RPE in the 4 groups showed a trend of rapid increase, then decreased gradually. There was no significant difference in HR, MAP, TT, or RPE between the 4 groups at the same time point (p > 0.05), in addition to this, when compared to the C group, the lactate, Ts, TS in the other 3 groups significant differences were observed at the corresponding time points (p < 0.05). The RMSSD, SDNN, HF, and LF levels in the 4 groups before exercise were not significantly different. The RMSSD and HF in the H40 and H80 groups were significantly decreased and other HRV indicators showed no significant difference after exercise. In sports performance measurement, the SJH and TTE were significantly decreased, but there was no significant difference in the 4 groups. The SR was no significant difference in the 4 groups after exercise. In conclusion, heat and humidity environments elicited generally greater physiological effects compared with the normal environment but did not affect sports performance in college football players.

IntroductionPatients with coronary artery disease (CAD) have a higher risk of developing cognitive impairment and mental health disorders compared to the general population. Physical exercise might improve their brain health. The overall goal of the HEART-BRAIN randomized controlled trial (RCT) is to investigate the effects of different types of exercise on brain health outcomes in patients with CAD, and the underlying mechanisms.MethodsThis three-arm, single-blinded RCT will include 90 patients with CAD (50–75 years). Participants will be randomized into: (1) control group—usual care (n = 30), (2) aerobic high-intensity interval training (HIIT) (n = 30), or (3) HIIT combined with resistance exercise training (n = 30). The 12-week intervention includes 3 supervised sessions (45-min each) per week for the exercise groups. Outcomes will be assessed at baseline and post-intervention. The primary outcome is to determine changes in cerebral blood flow assessed by magnetic resonance imaging. Secondary outcomes include changes in brain vascularization, cognitive measures (i.e., general cognition, executive function and episodic memory), and cardiorespiratory fitness. Additional health-related outcomes, and several potential mediators and moderators will be investigated (i.e., brain structure and function, cardiovascular and brain-based biomarkers, hemodynamics, physical function, body composition, mental health, and lifestyle behavior).ConclusionThe HEART-BRAIN RCT will provide novel insights on how exercise can impact brain health in patients with CAD and the potential mechanisms explaining the heart-brain connection, such as changes in cerebral blood flow. The results may have important clinical implications by increasing the evidence on the effectiveness of exercise-based strategies to delay cognitive decline in this high-risk population.Clinical trial registrationClinicalTrials.gov, identifier [NCT06214624].

Cardioprotective Effect of Exercise Training in Heart Failure Rats: Exercise Training Reduces Oxidative Stress Induced Nuclear Genomic Fragmentation

Backgroundβ-hydroxy-β-methylbutyric acid (HMB) is an interesting supplement in sports. However, literature sources present a limited number of studies that verify the efficacy of HMB intake over a longer time period among endurance athletes. For this reason, the aim of this study was to assess the effect of HMB supplementation on physical capacity, body composition and levels of biochemical markers in rowers.MethodsSixteen elite male rowers were administered a 12-week HMB supplementation (3×1 gHMB · day−1) and placebo administration (PLA) following the model of a randomised, placebo controlled, double-blind crossover study with a 10 days washout period. Over the course of the experiment, aerobic (maximal oxygen uptake, ventilatory threshold) and anaerobic (anaerobic power indices) capacity were determined, while analyses were conducted on body composition as well as levels of creatine kinase, lactate dehydrogenase, testosterone, cortisol and the T/C ratio. A normal distribution of variables was tested using the paired 2-tailed t-tests; the Mann–Whitney U-test or the Wilcoxon-signed rank test were applied for non-normally distributed variables.ResultsFollowing HMB supplementation, dot{mathrm{V}}{mathrm{O}}_2 max increased (+2.7 mL · min−1 · kg−1) significantly (p < 0.001) in comparison to its reduction after PLA (−1.0 mL · min−1 · kg−1). In turn, at the ventilatory threshold, a longer time was required to reach this point (+1.2 minHMB vs. −0.2 minPLA, p = 0.012), while threshold load (+0.42 W · kg−1HMB vs. −0.06 W · kg−1PLA, p = 0.002) and threshold heart rate (+9 bpmHMB vs. +1 bpmPLA, p < 0.001) increased. After HMB supplementation, fat mass decreased (−0.9 kgHMB vs. +0.8 kgPLA, p = 0.03). In relation to the initial values after HMB supplementation, the refusal time to continue in the progressive test was extended (p = 0.04), maximum load (p = 0.04) and anaerobic peak power (p = 0.02) increased. However, in relation to the placebo, no differences were observed in anaerobic adaptation or blood marker levels.ConclusionsThe results indicate that HMB intake in endurance training has an advantageous effect on the increase in aerobic capacity and the reduction of fat mass. It may also stimulate an increase in peak anaerobic power, while it seems to have no effect on other indices of anaerobic adaptation and levels of investigated markers in the blood.

The effects of oral glutamine supplementation on athletes after prolonged, exhaustive exercise

Background High-intensity interval training is emerging as a potential time efficient strategy in contemporary cardiac rehabilitation. According to current guidelines 150 minutes of moderate physical activity per week is reduced by half to 75 minutes if the week's activity is done at a vigorous intensity. Objective: The main goal of our study was to assess and compare high-intensity interval training (HIIT) with moderate-intensity continuous training (MICT) within cardiac rehabilitation after coronary artery bypass grafting. Methods Sixty three patients (48 male, 15 female, at the mean age of 57±12 years) after coronary artery bypass grafting were recruited into exercise training program on cycle ergometer. The training course started 2 weeks after surgery, lasted 4 weeks and then continued in an outpatient care after 3–6 months. MICT was considered as 50% to 75% of VO2 max (maximal oxygen consumption) or 50–75% of heart rate reserve, while HIIT was considered as ≥85% of VO2 max or ≥85% of heart rate reserve. Training protocols included constant load and ramp interval programs. Control group comprised 40 patients without exercise training program. The safety of HIIT/MICT was the primary end point in our study. Secondary end-points included body mass index, echo and hemodynamic parameters, NT-proBNP and HbA1c levels along with standard cardiorespiratory fitness indicators. Results Significant increase in anaerobic threshold (by 16.9%), VO2 max (by 18.6%) and tolerance of physical load in MET (by 6.4%) were mentioned in study groups compared to equivalent measurements in control group (9.7%, 7.9% and 5.4% correspondingly). Substantial changes were also observed in following variables compared to control group: body mass index reduced (p=0.0032), end diastolic diameter decreased (p=0.0315), LV ejection fraction improved (p=0.045), NT-proBNP reduced (p=0.0015) and HbA1c improved (p=0.023). While analyzing aerobic capacity alterations due to HIIT versus MICT by standardized mean difference (95% CI), HIIT was significantly superior to MICT. Aerobic capacity covered VO2 max (ml/kg/min), anaerobic threshold (%), work rate (Wt) and EQo2=VE/Vo2. Conclusions High-intensity interval training proved to be as safe as a moderate-intensity training in patients after coronary artery bypass grafting. It appeared to be significantly superior to moderate-intensity continuous training in improving cardiorespiratory fitness. Obtained results allow implementing aerobic interval training individually after open-heart surgery and shorten rehabilitation period.

Exercise may cause structural changes, which may increase cardiac functions such as enhanced pumping mechanism due to increased heart mass and volume. These changes may contribute to better performance. According to several studies, endurance training causes changes in structure of the heart since endurance trained athletes had larger LV dimensions, and mass. For instance, both cycling and rowing studies indicated positive structural adaptations of the heart; in addition, elite rowers had higher values than sub-elite rowers; this result suggests that elite athletes have higher level of adaptations supporting. Also, In all rat studies supported that endurance training increases LV mass, wall thickness and dimensions. Endurance training causes structural adaptations such as increased cardiac muscle mass, left ventricular wall thickness and chamber size. It is recommended that structural changes in the heart because of endurance training enhance the heart's ability to pump blood mainly by increasing its stroke volume. Training for adequate duration and time also should be taken in consideration to improve cardiac function because of the changes in the structure of the heart.