Maximal Oxygen Uptake Capacity Research Articles

The Variability of the Components of Fitness along the Menstrual Cycle.

This study aims to determine the variability of the components of fitness along the menstrual cycle (MC) of physically active eumenorrheic women. Fifteen subjects were monitored along two consecutive MCs through the calendar-based counting method in combination with a urine luteinizing hormone surge kit. Subjects were tested at the early follicular phase (EFP), pre-ovulatory or late follicular phase (LFP), and post-ovulatory or mid-luteal phase (MLP). In each session, the back squat one-repetition maximum (1-RM), maximum fat oxidation (MFO), maximum oxygen uptake (VO2max) and acute recovery capacity were determined. The results revealed a wide variability among components of fitness and a low to high variability among subjects (acute recovery: 3.6% [range 1.5 to 9.5%]; back squat 1-RM: 6.1% [range 2.2 to 11%]; VO2max: 6.6% [range 1.1 to 15%]; MFO: 23% [range 4.6 to 35%]). Despite the individual nature, considering the number and magnitude of the responses in each MC phase, VO2max and acute recovery capacity tended to be enhanced at the LFP, the MFO at the MLP, and the back squat 1-RM remained stable along the MC. Thus, practitioners are aware of which components are susceptible to change along the MC phase, but an individual monitoring is recommended.

Changes in real-world walking speed following 60-day bed-rest

The aim of this work was to explore whether real-world walking speed (RWS) would change as a consequence of 60-day bed-rest. The main hypothesis was that daily RWS would decrease after the bed-rest, with a subsequent recovery during the first days of re-ambulation. Moreover, an exploratory analysis was done in order to understand whether there is an agreement between the loss in RWS after bed-rest and the loss in the maximum oxygen uptake capacity (VO2max), or the loss in maximal vertical jump power (JUMP) respectively. Twenty-four subjects were randomly assigned to one of three groups: a continuous artificial gravity group, an intermittent artificial gravity group, or a control group. The fitted linear mixed effects model showed a significant decrease (p < 0.001) of RWS after the 60-day bed-rest and a subsequent increase (p < 0.001) of RWS during the 14-day recovery period in the study facility. No or little agreement was found between the loss in RWS and the loss in VO2max capacity or the loss in maximal vertical jumping power (RWS vs. VO2max: p = 0.81, RWS vs. JUMP: p = 0.173). Decreased RWS after bed-rest, with a follow-up recovery was observed for all three groups, regardless of the training intervention. This suggests that RWS, also in these settings, was able to reflect a de-conditioning and follow-up recovery process.

Hemoglobin Mass and Blood Volume in Swimming: A Comparison Between Highly Trained, Elite, and World-Class Swimmers.

Total hemoglobin mass (tHbmass) and blood volume (BV) are important determinants of maximal oxygen uptake and endurance capacity. Higher-caliber endurance athletes usually possess higher tHbmass and BV values. This study aimed to compare tHbmass and BV among swimmers of diverse competitive calibers and distances. Thirty swimmers (16 female and 14 male) participated in the study: 3 were tier 5, world class (869 [59] FINA points); 15 were tier 4, elite/international (853 [38] points); and 12 were tier 3, highly trained/national (808 [35] points). They specialized in competition distances ranging from 200m to open-water 10km. Between February 2019 and February 2020, all swimmers had their tHbmass and BV measured by carbon monoxide rebreathing 1 to 6 times and participated in multiple competitions and race events. Relative tHbmass and BV were not different (P > .05) between tiers among women or among men (pooled tHbmass values 14.5 [0.5], 12.5 [1.5], 12.6 [2.3]g/kg for tier 5, tier 4, and tier 3, respectively). No differences were observed in relative tHbmass (P = .215) and BV (P = .458) between pool and open-water swimmers or between 200-, 400-, and 1500-m specialists (P > .05). No significant correlations were found between the highest measured absolute or relative tHbmass and BV and the highest FINA points scored over the follow-up period (R = -.42-.17, P = .256-.833), irrespective of competition distance. tHbmass and BV values did not differ between swimmers of different calibers or among competition distances. Furthermore, these values did not correlate with FINA points, either in males or in females. The present results indicate that hematological characteristics may have a lesser impact on swimming performance than on land-based endurance sports.

Assessing aerobic endurance in elite female cricket players

To assess and compare the aerobic endurance levels of elite female cricket players from Bangladesh and India. This study’s participants were 50 elite female cricket players (ages 18-30 years), with 25 players from each country. They were all considered elite players based on their performance and experience in national and international cricket tournaments. To measure aerobic endurance fitness, the participants underwent a Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1), which is widely used to measure an individual's maximal oxygen uptake (VO2max) and aerobic capacity. The data collected were analysed using descriptive statistics and inferential statistics. The test of Normality, mean, and standard deviation were calculated for each group, and a t-test was used to compare the mean scores of the two groups. A p-value of less than .05 is considered statistically significant. The data were analysed using the statistical software SPSS version 26. The study found that the Indian female cricket players had a significantly higher aerobic endurance fitness level than the Bangladeshi players. The mean VO2max of the Indian players was 46.76 ml/kg/min, while the Bangladeshi players' mean VO2max was 43.60 ml/kg/min. Additionally, the Indian players had a higher mean score in total distance covered in YYIRT1 (1233.6 m) than the Bangladeshi players (857.6). These differences were found to be statistically significant (p &lt; .05). These findings suggest that there may be a difference in the training and preparation methods between the two countries, leading to a higher aerobic endurance fitness level among Indian players.

Investigation of Physiological Exercise Parameters and Sleep Status of Elite Karate Athletes

Aim: The aim of this study was to determine sleep quality and exercise-related physiological parameters (heart rate, heart rate reserve, cardiac output, blood pressure, maximum oxygen uptake capacity) of elite karate athletes in Trabzoninvolved. Materials and Methods: Ten athletes, 3 girls and 7 boys, who are interested in karate at an elite level in Trabzon, participated in the study. Anthropometric measurements and body mass index measurements were made. Cardiopulmonary exercise test (CPET) was performed with a gradually increasing intensity (15W/min) bicycle ergometer test protocol. In this study, sleep parameters of the athletes were obtained by using the physical activity measurement holter (Sensewear Armband). Results: The mean age of the individuals was 17.8±1.39 years (n=10), the mean height was 169.0±8.1 cm (n=10), the mean weight was 63.99±7.64 kg (n=10), and the mean body mass index was 22.41 kg/m² (n=10) was. Average value for oxygen consumption (VO₂) at maximum workload level 43±8 ml/kg/min (n=10, 99±12% of predicted), average maximum power 197±27.50 Watts (n=10, 92%±% predicted) 14), mean minute ventilation (VE) 103±28 L/min (n=10, 95±22% of predicted), mean heart rate (HR) 181±12 beats/min (n=10, % predicted) 93±7) and mean oxygen (O₂) heart rate at maximum workload level was 15.20±2.90 ml/beat (n=10, 115.1±17.75% of predicted). The average lying down time of the athletes was 8 hours 8 minutes ±2 hours 26 minutes (n=9), sleep time was 6 hours 9 minutes±2 hours 30 minutes (n=9), and sleep efficiency was 74±12%. Conclusion: The findings of this study show that the participating athletes had a good aerobic capacity and a good training level for the sport branch they are were engaged

ANÁLISE DA RESISTÊNCIA CARDIOPULMONAR SOB DIFERENTES CARGAS EM EXERCÍCIOS AERÓBICOS

ABSTRACT Introduction The key objective of aerobic exercise is enhancing cardiorespiratory endurance. On the national gymnastics plan implementation, the idea of lifelong sports was gradually accepted by the masses, and the aerobic gymnastics concept was sweeping the world. Objective Analyze the cardiorespiratory endurance responses in female college students under different frequencies in aerobic exercise. Methods 20 female professors and civilian women were randomly selected and divided into two groups. The experimental group performed 45 and 90 minutes of aerobic exercise to analyze changes in cardiopulmonary function before and after each exercise. Results After 16 weeks of aerobic exercise with different loads, all young women who had participated in the program training showed a significant increase in vital capacity and maximal oxygen uptake capacity. The vital capacity of the 90-min aerobic exercise group was significantly higher than that of the 45-min aerobic exercise group (P&lt;0.05). Conclusion The establishment of a cardiorespiratory endurance response model can accurately analyze the effects of different aerobic exercise frequencies on cardiorespiratory endurance. Evidence Level II; Therapeutic Studies – Investigating the results.

Abstract 10388: Impact Of Right Ventricular Function On Cardiopulmonary Exercise Capacity In Mitral Regurgitation Patients Undergoing Transcatheter Mitral Valve Repair

Background/Objectives: To investigate the role of right ventricular (RV) function on exercise capacity in patients undergoing transcatheter mitral valve repair (TMVR) we aimed to perform cardiopulmonary exercise testing (CPET) and to show a correlation between an improved RV function and maximal and submaximal exercise capacity. Methods: Constant work rate exercise time testing (CWRET) reflects submaximal/endurance exercise capacity, which is more likely to be relevant for daily life activities, and gives a more differentiated physiologic insight into the nature of exercise intolerance. Thus, 28 Patients with mitral regurgitation (MR) and symptomatic heart failure (NYHA≥II) underwent CPET by assessment of maximal oxygen uptake (peak VO 2 ) and submaximal exercise capacity (at 75% of maximal achieved work rate in the initial incremental exercise test) accompanied by echocardiography prior to TMVR and 3 months post-procedure. Results: Mean age of the patients was 75.0±8.7 years and 32.1% of them were female. One patient presented a reduction of MR &lt;2 grades. RV function (assessed with fractional area change, tricuspid annular plane systolic excursion, longitudinal strain of the RV free wall and S`) was at least moderately impaired in 25% of the patients. The submaximal exercise capacity of these patients was impaired, but did not significantly differ (416.4±359.6sec vs. 296.1 ±216.5sec; p=0.152) compared to patients without a deteriorated RV function. Three months after intervention, exercise time at 75% of maximal achieved work rate significantly improved (from 337.4±262.2sec to 517.4±393. sec p=0.006), reflecting a gain in submaximal exercise tolerance. peak VO 2 showed a positive trend, but no statistically significant difference (10.3±3.1ml/min/kg vs. 11.3±3.4ml/min/kg; p=0.056). RV function (at least 2 of 4 parameters) improved in 35.7% and these patients showed a significantly higher submaximal exercise time increasement (471.7±153.9sec vs. 82.7±47.0sec, p=0.003). Discussion/Conclusions: TMVR may have a beneficial effect on RV remodeling. Furthermore, submaximal exercise capacity is significantly increased, reflecting an improvement especially regarding daily life activities in MR patients and impaired RV function.

Chronic experimental hyperoxia elevates aerobic scope: a valid method to test for physiological oxygen limitations in fish.

Experimental hyperoxia has been shown to enhance the maximum oxygen uptake capacity of fishes under acute conditions, potentially offering an avenue to test prominent physiological hypotheses attempting to explain impacts of climate warming on fish populations (e.g., gill-oxygen limitation driving declines in fish size). Such benefits of experimental hyperoxia must persist under chronic conditions if it is to provide a valid manipulation to test the relevant hypotheses, yet the long-term benefits of experimental hyperoxia to oxygen uptake capacity have not been examined. Here, the authors measured aerobic metabolic performance of Galaxias maculatus upon acute exposure to hyperoxia (150% air saturation) and after 5months of acclimation, at both 15°C and 20°C. Acute hyperoxia elevated aerobic scope by 74%-94% relative to normoxic controls, and an elevation of 58%-73% persisted after 5months of hyperoxia acclimation. When hyperoxia-acclimated fish were acutely transitioned back to normoxia, they maintained superior aerobic performance compared with normoxic controls, suggesting an acclimation of the underlying metabolic structures/processes. In demonstrating the long-term benefits of experimental hyperoxia on the aerobic performance of a fish, the authors encourage the use of such approaches to disentangle the role of oxygen in driving the responses of fish populations to climate warming.

Remote ischemic preconditioning enhances aerobic performance by accelerating regional oxygenation and improving cardiac function during acute hypobaric hypoxia exposure.

Remote ischemic preconditioning (RIPC) may improve exercise performance. However, the influence of RIPC on aerobic performance and underlying physiological mechanisms during hypobaric hypoxia (HH) exposure remains relatively uncertain. Here, we systematically evaluated the potential performance benefits and underlying mechanisms of RIPC during HH exposure. Seventy-nine healthy participants were randomly assigned to receive sham intervention or RIPC (4 × 5 min occlusion 180 mm Hg/reperfusion 0 mm Hg, bilaterally on the upper arms) for 8 consecutive days in phases 1 (24 participants) and phase 2 (55 participants). In the phases 1, we measured the change in maximal oxygen uptake capacity (VO2max) and muscle oxygenation (SmO2) on the leg during a graded exercise test. We also measured regional cerebral oxygenation (rSO2) on the forehead. These measures and physiological variables, such as cardiovascular hemodynamic parameters and heart rate variability index, were used to evaluate the intervention effect of RIPC on the changes in bodily functions caused by HH exposure. In the phase 2, plasma protein mass spectrometry was then performed after RIPC intervention, and the results were further evaluated using ELISA tests to assess possible mechanisms. The results suggested that RIPC intervention improved VO2max (11.29%) and accelerated both the maximum (18.13%) and minimum (53%) values of SmO2 and rSO2 (6.88%) compared to sham intervention in hypobaric hypoxia exposure. Cardiovascular hemodynamic parameters (SV, SVRI, PPV% and SpMet%) and the heart rate variability index (Mean RR, Mean HR, RMSSD, pNN50, Lfnu, Hfnu, SD1, SD2/SD1, ApEn, SampEn, DFA1and DFA2) were evaluated. Protein sequence analysis showed 42 unregulated and six downregulated proteins in the plasma of the RIPC group compared to the sham group after HH exposure. Three proteins, thymosin β4 (Tβ4), heat shock protein-70 (HSP70), and heat shock protein-90 (HSP90), were significantly altered in the plasma of the RIPC group before and after HH exposure. Our data demonstrated that in acute HH exposure, RIPC mitigates the decline in VO2max and regional oxygenation, as well as physiological variables, such as cardiovascular hemodynamic parameters and the heart rate variability index, by influencing plasma Tβ4, HSP70, and HSP90. These data suggest that RIPC may be beneficial for acute HH exposure.

102: EFFECT OF A MULTIMODAL PREHABILITATION PROGRAM ON POSTOPERATIVE RECOVERY AND MORBIDITY IN PATIENTS UNDERGOING A MINIMALLY INVASIVE ESOPHAGECTOMY

Abstract Background and aim Despite recent advancements in perioperative care, postoperative morbidity following an esophagectomy remains substantial. Studies in other major abdominal surgery, have shown that prehabilitation can improve short-term outcomes. This single-center cohort study investigated the effect of prehabilitation in patients undergoing minimally invasive Ivor-Lewis esophagectomy (MIE-IL). Methods Data were collected on consecutive patients receiving a standardized ERAS program that included direct start of oral feeding following MIE-IL (from postoperative day one), between October 2015 and February 2020. The intervention group comprised patients enrolled in the PREPARE prehabilitation program that was implemented in 2018 as the standard care pathway for all patients. The control group comprised a retrospective cohort prior to implementation of PREPARE. Postoperative outcomes included (functional) recovery, length of hospital stay (LOHS), cardiopulmonary complications (CPC) and other predefined outcomes. Results The PREPARE group comprised 52 patients and control group 43 patients. Median time to functional recovery was 6 vs. 7 days (P = 0.074) and LOHS 7 vs. 8 days (P = 0.039) in the PREPARE and control group, respectively. Hospital readmission rate was 9.6% vs. 14.3% (P = 0.484). Although thirty-day overall postoperative complication rate did not differ statistically significantly (P = 0.106), a clinically relevant reduction of 17% was observed in PREPARE patients. Similarly, CPC rate was 14% lower in the PREPARE group (P = 0.190). Anastomotic leakage rate was similar (9.6% vs 14.0%; P = 0.511). Despite no difference in severity (Clavien-Dindo) of complications (P = 0.311), ICU readmission rate was lower in PREPARE patients (3.8% vs. 16.3%, P = 0.039). In the PREPARE group wherein maximum oxygen uptake capacity (VO2max) was assessed preoperatively during a Steep Ramp Test, VO2max was lower at baseline in patients diagnosed with postoperative complications (P = 0.011). There were no data on VO2max in the control group. Conclusion Prehabilitating patients prior to a MIE-IL led to a shorter LOHS and reduced ICU readmission rate. Additionally, a clinically relevant improvement in (functional) recovery and reduction in postoperative morbidity was observed in patients that were prehabilitated.

Effects of 150- and 450-mL Acute Blood Losses on Maximal Oxygen Uptake and Exercise Capacity.

This study investigated whether maximal oxygen uptake (V˙O2max) and exercise capacity are affected by small acute blood loss (150 mL) and elucidated compensatory mechanisms. Thirteen male subjects (V˙O2max, 63 ± 9 mL·kg-1·min-1; mean ± SD) performed incremental exercise to exhaustion on a cycle ergometer in three experimental conditions: in euvolemia (control; blood volume [BV], 6.0 ± 0.7 L) and immediately after acute BV reductions of 150 mL (BVR150mL) and 450 mL (BVR450mL). Changes in plasma volume (PV) and BV during exercise were calculated from hematocrit, hemoglobin concentration, and hemoglobin mass (carbon monoxide rebreathing). The reduction in V˙O2max per milliliter of BVR was 2.5-fold larger after BVR450mL compared with BVR150mL (-0.7 ± 0.3 vs -0.3 ± 0.6 mL·min-1·mL-1, P = 0.029). V˙O2max was not significantly changed after BVR150mL (-1% ± 2%, P = 0.124) but reduced by 7% ± 3% after BVR450mL (P < 0.001) compared with control. Peak power output only decreased after BVR450mL (P < 0.001). At maximal exercise, BV was restored after BVR150mL compared with control (-50 ± 185 mL, P = 0.375) attributed to PV restoration, which was, however, insufficient in restoring BV after BVR450mL (-281 ± 184 mL, P < 0.001). The peak heart rate tended to increase (3 ± 5 bpm, P = 0.062), whereas the O2 pulse (-2 ± 1 mL per beat, P < 0.001) and vastus lateralis tissue oxygenation index (-4% ± 8% points, P = 0.080) were reduced after BVR450mL, suggesting decreased stroke volume and increased leg O2 extraction. The deteriorations of V˙O2max and of maximal exercise capacity accelerate with the magnitude of acute blood loss, likely because of a rapid PV restoration sufficient to establish euvolemia after a small but not after a moderate blood loss.

Cemented stems in healthy elderly patients result in higher hypoxia despite a paradoxical lower femoral increase of intramedullary pressure.

Hypoxia is a well-known complication in cemented arthroplasty; however, it is not known whether the level of hypoxia is related to the intramedullary pressure or to the age of the patient; therefore, we studied the intramedullary pressure and level of hypoxia in patients undergoing cemented arthroplasty. A prospective study was performed during cemented arthroplasties in 25 patients with an average age of 66.2 ± 12.1 years old. The intramedullary pressure (IMP) was measured by placing a pressure transducer within the bone while simultaneously measuring the pulse oximetry arterial oxygen saturation (SpO2), pulse, and blood pressure. These variables were obtained immediately after spinal anaesthesia, five minutes after cementation, and 15 minutes after prosthesis insertion. One hundred percent of patients had hypoxia at some level, but 83% of elderly patients (older than 66.5 years) had hypoxia (SpO2 <94%) as compared to only 23% of younger patients (p = 0.006). In the group of young patients, IMP was roughly increased 32 times as compared with baseline level, with as consequences a decrease of 4% of SpO2 (from 98.3 to 94.15%); in the elderly group, the IMP was only increased 20 times, but a decrease of 6% of SpO2 (from 97.25 to 91%) was observed. This series demonstrated higher hypoxia in elderly healthy patients despite a paradoxical lower femoral increase of intramedullary pressure as compared with younger patients. This hypoxia is probably not only related to the cement but also to the patient's age with decline of maximum oxygen uptake capacity and increase bone porosity. ClinicalTrials.gov Identifier: NCT03930537 https://clinicaltrials.gov/ct2/show/NCT03930537.

Dietary quercetin supplementation does not increase maximal oxygen uptake and physical work capacity

Aim: Th e purpose of our study was to use a time-series design to investigate the eff ect of dietary quercetin supplementation on peak oxygen uptake (VO2peak) and physical work capacity. Methods and organization of the study: Nine recreationally-active men and women completed a treadmill-running graded exercise test (GXT) weekly (excepting wk 8) for 14 weeks. During the fi rst 3 and last 3 weeks, no quercetin supplementation was administered. During weeks 4-11, subjects ingested four soft Q-chews (Nutravail Technologies) per day containing quercetin (1 g/d), vitamin C, vitamin B3 and folic acid. A control group of 5 men were also tested during the fi rst and last week. Research results: VO2peak and test time remained stable throughout the 14 weeks at approximately 3.5±1.1 L/min and 6±1.6 min. Using a one-way repeated measures ANOVA, there was no signifi cant diff erence among means (P &gt; 0.05) for either measure. Th ere was no trend for individual or mean values to increase above baseline during the treatment period. No changes occurred in the control group. Conclusions: We conclude that dietary quercetin supplementation with 1 g/d for 8 wk in non-endurance-trained men and women does not increase VO2peak or physical work capacity. Keywords: exercise, fl avonoids, muscle oxidative capacity, oxygen consumption

Protein supplementation elicits greater gains in maximal oxygen uptake capacity and stimulates lean mass accretion during prolonged endurance training: a double-blind randomized controlled trial

Endurance training induces numerous cardiovascular and skeletal muscle adaptations, thereby increasing maximal oxygen uptake capacity (VO2max). Whether protein supplementation enhances these adaptations remains unclear. The present study was designed to determine the impact of protein supplementation on changes in VO2max during prolonged endurance training. We used a double-blind randomized controlled trial with repeated measures among 44 recreationally active, young males. Subjects performed 3 endurance training sessions per week for 10 wk. Supplements were provided immediately after each exercise session and daily before sleep, providing either protein (PRO group; n=19; 21.5±0.4 y) or an isocaloric amount of carbohydrate as control (CON group; n=21; 22.5±0.5 y). The VO2max, simulated 10-km time trial performance, and body composition (dual-energy X-ray absorptiometry) were measured before and after 5 and 10 wk of endurance training. Fasting skeletal muscle tissue samples were taken before and after 5 and 10 wk to measure skeletal muscle oxidative capacity, and fasting blood samples were taken every 2 wk to measure hematological factors. VO2max increased to a greater extent in the PRO group than in the CON group after 5 wk (from 49.9±0.8 to 54.9±1.1 vs 50.8±0.9 to 53.0±1.1 mL · kg-1 · min-1; P<0.05) and 10 wk (from 49.9±0.8 to 55.4±0.9 vs 50.8±0.9 to 53.9±1.2 mL · kg-1 · min-1; P<0.05). Lean body mass increased in the PRO group whereas lean body mass in the CON group remained stable during the first 5 wk (1.5±0.2 vs 0.1±0.3 kg; P<0.05) and after 10 wk (1.5±0.3 vs 0.4±0.3 kg; P<0.05). Throughout the intervention, fat mass reduced significantly in the PRO group and there were no changes in the CON group after 5 wk (-0.6±0.2 vs -0.1±0.2 kg; P>0.05) and 10 wk (-1.2±0.4 vs -0.2±0.2 kg; P<0.05). Protein supplementation elicited greater gains in VO2max and stimulated lean mass accretion but did not improve skeletal muscle oxidative capacity and endurance performance during 10 wk of endurance training in healthy, young males. This trial was registered at clinicaltrials.gov as NCT03462381.

The developing athlete's heart: a cohort study in young athletes transitioning through adolescence.

Athlete's heart is a term used to describe physiological changes in the hearts of athletes, but its early development has not been described in longitudinal studies. This study aims to improve our understanding of the effects of endurance training on the developing heart. Cardiac morphology and function in 48 cross-country skiers were assessed at age 12 years (12.1 ± 0.2 years) and then again at age 15 years (15.3 ± 0.3 years). Echocardiography was performed in all subjects including two-dimensional speckle-tracking strain echocardiography and three-dimensional echocardiography. All participants underwent cardiopulmonary exercise testing at both ages 12 and 15 years to assess maximal oxygen uptake and exercise capacity. Thirty-one (65%) were still active endurance athletes at age 15 years and 17 (35%) were not. The active endurance athletes had greater indexed maximal oxygen uptake (62 ± 8 vs. 57 ± 6 mL/kg/min, P < 0.05) at follow-up. There were no differences in cardiac morphology at baseline. At follow-up the active endurance athletes had greater three-dimensional indexed left ventricular end-diastolic (84 ± 11 mL/m2 vs. 79 ± 10 mL/m2, P < 0.05) and end-systolic volumes (36 ± 6 mL/m2 vs. 32 ± 3 mL/m2, P < 0.05). Relative wall thickness fell in the active endurance athletes, but not in those who had quit (-0.05 ΔmL/m2 vs. 0.00 mL/m2, P = 0.01). Four active endurance athletes had relative wall thickness above the upper reference values at baseline; all had normalised at follow-up. After an initial concentric remodelling in the pre-adolescent athletes, those who continued their endurance training developed eccentric changes with chamber dilatation and little change in wall thickness. Those who ceased endurance training maintained a comparable wall thickness, but did not develop chamber dilatation.

EFFECT OF 8 WEEKS HIGH INTENSITY INTERVAL TRAINING ON MAXIMUM OXYGEN UPTAKE CAPACITY AND RELATED CARDIO-RESPIRATORY PARAMETERS AT ANAEROBIC THRESHOLD LEVEL OF INDIAN MALE FIELD HOCKEY PLAYERS

Aim: In order to achieve maximal performance, need for high oxygen uptake is complemented with rigorous training program. To evaluate the effect of 8 weeks high intensity interval training (HIIT) on maximum oxygen uptake capacity and related cardio-respiratory parameters at anaerobic threshold level. Materials and methods: High intensity interval training programme was implemented among 20 trained young male hockey players for 3 days/week. The training set included 2 minutes of intense sprint workout followed by a minute each of active recovery and complete rest. The point of anaerobic threshold was identified with ventilatory equivalent method while the players were subjected to exercise on computerized bicycle ergometer. Results: Present study depicts significant increase in maximum oxygen consumption (+8%, p=0.000), maximum heart rate (+3%, p=0.01) and glycogen content (+3%, p=0.421) with significant decrease in pre-exercise heart rate (-7%, p=0.001), recovery heart rate (-7%, p=0.000) and average breathing frequency (-6%, p=0.014) after 8 weeks of interval training. Oxygen consumption (p=0.505), heart rate (p=0.000) and work load (p=0.004) were also improved significantly at anaerobic threshold level by 11%, 6% and 9% respectively. Conclusion: HIIT protocol ultimately allows the athlete to exercise at higher workload with greater cardiac proficiency within the aerobic zone. Article visualizations:

Dietary feeding pattern does not modulate the loss of muscle mass or the decline in metabolic health during short-term bed rest.

Short periods of bed rest lead to the loss of muscle mass and quality. It has been speculated that dietary feeding pattern may have an impact upon muscle protein synthesis rates and, therefore, modulate the loss of muscle mass and quality. We subjected 20 healthy men (age: 25 ± 1 yr, body mass index: 23.8 ± 0.8 kg/m2) to 1 wk of strict bed rest with intermittent (4 meals/day) or continuous (24 h/day) enteral tube feeding. Participants consumed deuterium oxide for 7 days before bed rest and throughout the 7-day bed rest period. Prior to and immediately after bed rest, lean body mass (dual energy X-ray absorptiometry), quadriceps cross-sectional area (CSA; CT), maximal oxygen uptake capacity (V̇o2peak), and whole body insulin sensitivity (hyperinsulinemic-euglycemic clamp) were assessed. Muscle biopsies were collected 7 days before, 1 day before, and immediately after bed rest to assess muscle tracer incorporation. Bed rest resulted in 0.3 ± 0.3 vs. 0.7 ± 0.4 kg lean tissue loss and a 1.1 ± 0.6 vs. 0.8 ± 0.5% decline in quadriceps CSA in the intermittent vs. continuous feeding group, respectively (both P < 0.05), with no differences between groups (both P > 0.05). Moreover, feeding pattern did not modulate the bed rest-induced decline in insulin sensitivity (-46 ± 3% vs. 39 ± 3%; P < 0.001) or V̇o2peak (-2.5 ± 2.2 vs. -8.6 ± 2.2%; P < 0.010) (both P > 0.05). Myofibrillar protein synthesis rates during bed rest did not differ between the intermittent and continuous feeding group (1.33 ± 0.07 vs. 1.50 ± 0.13%/day, respectively; P > 0.05). In conclusion, dietary feeding pattern does not modulate the loss of muscle mass or the decline in metabolic health during 1 wk of bed rest in healthy men.

Validity of Innovative Smartphone Sport-supported Calculator and Gas Analysis Indirect Calorimetry in Energy Expenditure Estimation

PURPOSE:To apply innovative Smartphone Sport-supported Fat & Glucose Calculator (SSFGC) in endurance exercise and evaluate validity of innovative SSFGC and Gas Analysis Indirect Calorimetry in fat and glucose consumption estimation during cycling endurance exercise. METHODS:Twelve healthy male cyclists (age : 31.8 ± 3.2 yr, height : 171.6 ± 7.9 cm, weight : 71.2 ± 5.0 kg, peak oxygen uptake (VO2peak): 46.2 ± 5.6 mL / min / kg, The maximum for power : 240 ± 50 watt, progressive exercise load (15watts/min, graded exercise testing, GXT) exhaustive time : 982 ± 197 sec, RER: 1.1 ± 0.1) were recruited and conducted to measure the maximal oxygen uptake capacity and basic physiological data before the study. During 1 Hr endurance exercise (30% VO2 peak-80 % VO2 peak), endurance exercise, subjects were required to comply with SSFGC. All data are expressed as mean ± standard deviation (SD). The level of significance was set at p ≤.05. RESULTS: The study found that there is a high positive correlation between SSFGC and Gas Analysis Indirect Calorimetry in glucose (r = .994, p < .05) and fat (30% VO2 peak-50% VO2 peak: r = .888, p < .05; 60 % VO2 peak-80 % VO2 peak: r = .817, p < .05) consumption estimation during cycling endurance exercise. CONCLUSIONS:Innovative SSFGC can be stability used for fat and glucose metabolism measurement, and provide a theoretical basis for future further applications.

Evaluation of T-wave alternans activity under stress conditions after 5 d and 21 d of sedentary head-down bed rest

It is well known that prolonged microgravity leads to cardiovascular deconditioning, inducing significant changes in autonomic control of the cardiovascular system. This may adversely influence cardiac repolarization, and provoke cardiac rhythm disturbances. T-wave alternans (TWA), reflecting temporal and spatial repolarization heterogeneity, could be affected. The aim of this work was to test the hypothesis that 5 d and 21 d head-down (−6°) bed rest (HDBR) increases TWA, thus suggesting a higher underlying electrical instability and related arrhythmogenic risk.Forty-four healthy male volunteers were enrolled in the experiments as part of the European Space Agency’s HDBR studies. High-fidelity ECG was recorded during orthostatic tolerance (OT) and aerobic power (AP) tests, before (PRE) and after HDBR (POST). A multilead scheme for TWA amplitude estimation was used, where non-normalized and T-wave amplitude normalized TWA indices were computed. In addition, spectral analysis of heart rate variability during OT was assessed.Both 5 d and 21 d HDBR induced a reduction in orthostatic tolerance time (OTT), as well as a decrease in maximal oxygen uptake and reserve capacity, thus suggesting cardiovascular deconditioning. However, TWA indices were found not to increase. Interestingly, subjects with lower OTT after 5 d HDBR also showed higher TWA during recovery after OT testing, associated with unbalanced sympathovagal response, even before the HDBR. In contrast with previous observations, augmented ventricular heterogeneity related to 5 d and 21 d HDBR was not sufficient to increase TWA under stress conditions.

Safety and efficacy of exercise training in adults with Pompe disease: evalution of endurance, muscle strength and core stability before and after a 12 week training program.

BackgroundPompe disease is a proximal myopathy. We investigated whether exercise training is a safe and useful adjuvant therapy for adult Pompe patients, receiving enzyme replacement therapy.MethodsTraining comprised 36 sessions of standardized aerobic, resistance and core stability exercises over 12 weeks. Before and after, the primary outcome measures safety, endurance (aerobic exercise capacity and distance walked on the 6 min walk test) and muscle strength, and secondary outcome measures core stability, muscle function and body composition, were evaluated.ResultsOf 25 patients enrolled, 23 successfully completed the training. Improvements in endurance were shown by increases in maximum workload capacity (110 W before to 122 W after training, [95 % CI of the difference 6 · 0 to 19 · 7]), maximal oxygen uptake capacity (69 · 4 % and 75 · 9 % of normal, [2 · 5 to 10 · 4]), and maximum walking distance (6 min walk test: 492 meters and 508, [−4 · 4 to 27 · 7] ). There were increases in muscle strength of the hip flexors (156 · 4 N to 180 · 7 N [1 · 6 to 13 · 6) and shoulder abductors (143 · 1 N to 150 · 7 N [13 · 2 to 35 · 2]). As an important finding in secondary outcome measures the number of patients who were able to perform the core stability exercises rose, as did the core stability balancing time (p < 0.05, for all four exercises). Functional tests showed small reductions in the time needed to climb four steps (2 · 4 sec to 2 · 1, [− 0 · 54 to −0 · 04 ]) and rise to standing position (5 · 8 sec to 4 · 8, [−2 · 0 to 0 · 0]), while time to run, the quick motor function test results and body composition remained unchanged.ConclusionsOur study shows that a combination of aerobic, strength and core stability exercises is feasible, safe and beneficial to adults with Pompe disease.