VO2max Test Research Articles

Effectiveness of Brisk Walking on VO2 Max, Agility and Flexibility in Physically Inactive Children

Background and Objectives: Physical inactivity is on the ascent in today's technology environment, and it is one of the main risk factors for noncommunicable diseases and death worldwide. It raises the risk of a broad range of lifestyle diseases. Physical inactivity is the world's fourth largest cause of death. The use of tech gadgets and transportation infrastructure may lead to a higher level of physical inactivity in children and adolescents, which has an impact on their physical fitness and academic performance. To encourage physical exercise and fitness, early intervention is required. Therefore, this study was undertaken to determine the effect of brisk walking on VO2 Max, agility, and flexibility in physically inactive children Methodology: Thirty subjects were selected based on inclusion and exclusion criteria, then divided in to two groups. Group A (Experimental group = 15) received warm up exercise, brisk walking and cool down exercises. Group B (control group = 15) does not receive any exercise. Exercise programme was held for 3 days per week for 40 minutes for 6 weeks. Pre and post measurements were taken using queen college step test for VO2 Max, agility t test and modified sit and reach test for flexibility. Results & Discussion: Paired t test is used to analyze the results within the group and independent t test were used to analyze the results between the group. The significant level kept at p ≤ 0.05. From pre to post six week intervention, a statistically significant changes were observed in all outcome measures. In paired t test VO2 Max, flexibility and agility expressed significant improvement in experimental group. In case of independent t test all the three parameters of the experimental group expressed significant improvement compared to control group. Conclusion: The study concluded that brisk walking exercise is effective in improving VO2 Max, agility and flexibility in physically inactive children. The experimental group shows significant improvement in all three parameters compared to control group. Keywords: Brisk walking, VO2 Max, agility, Flexibility, Physical inactivity, Queen college step test, modified sit and reach test, Agility t test.

Impact of novel glucose-lowering therapies on physical function in people with type 2 diabetes: A systematic review and meta-analysis of randomised placebo-controlled trials.

We investigated evidence from randomised, placebo-controlled trials of novel glucose-lowering therapies; sodium-glucose co-transporter-2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP4i) and glucagon-like peptide-1 receptor agonists (GLP-1RA), on physical function in people with type 2 diabetes (T2D). PubMed, Medline, Embase and Cochrane library were searched from 1 April 2005 to 20 January 2022. The primary outcome was change in physical function in groups receiving a novel glucose-lowering therapy versus placebo at the trial end-point. Eleven studies met our criteria including nine for GLP-1RA and one each for SGLT2i and DPP4i. Eight studies included a self-reported measure of physical function, seven with GLP-1RA. Pooled meta-analysis showed an improvement of 0.12 (0.07, 017) points in favour of novel glucose-lowering therapies, mainly GLP-1RA. These findings were consistent when assessed individually for commonly used subjective assessments of physical function; namely the Short-Form 36 item-questionnaire (SF-36; all investigating GLP-1RA) and the Impact of Weight on Quality of Life-Lite (IWQOL-LITE; all, except one, exploring GLP-1RA) with estimated treatment differences (ETDs) of 0.86 (0.28, 1.45) and 3.72 (2.30, 5.15) respectively in favour of novel GLTs. For objective measures of physical function (VO2max and 6-minute walk test (6MWT)) no significant between-group differences between the intervention and the placebo were found. GLP-1RAs showed improvements in self-reported outcomes of physical function. However, there is limited evidence to draw definitive conclusions especially because of lack of studies exploring the impact of SGLT2i and DPP4i on physical function. There is a need for dedicated trials to establish the association between novel agents and physical function.

Hubungan Pengetahuan Gizi dan Asupan Zat Gizi Makro dengan Tingkat Kebugaran Jasmani Atlet Sepak Bola di SSB Ganesha Putra FC Purwodadi

Football athletes need good physical fitness. Fulfillment of macronutrient intake and knowledge of nutrients is important to consider in helping to increase the level of physical fitness of athletes. The study used a cross sectional design with a sample of 39 athletes. Macronutrient intake was obtained from the 3x24 hour recall intake interview, nutrition knowledge data was obtained from filling out the questionnaire questions, physical fitness data was obtained from the VO2 max test, the Multistage Fitness Test. Data analysis used Bivariate Gamma test analysis in the Statistical Package for the Social Science program. The majority of carbohydrate intake is less (56.4%), adequate protein intake (51.3%), low fat intake (48.7%), moderate nutritional knowledge (51.3%) and moderate physical fitness (53.8%). Then the Bivariate test analysis showed that carbohydrate intake (p = 0.024) had a relationship with physical fitness level because the p value 0.05, while protein intake (p = 0.084), fat intake (p = 0.072), and nutritional knowledge (p = 0.072). 0.107) has no relationship with the level of physical fitness. Carbohydrate intake can affect the level of physical fitness of athletes, so it is necessary to provide adequate intake of other nutrients to improve athlete fitness.

The validity and reliability of walking as exercise modality during VO2max testing.

Although walking is the most common exercise modality in daily life for most humans, running and cycling are the most applied exercise modalities during maximal oxygen uptake (VO<inf>2max</inf>) testing. The aim of this study was to assess the reliability and validity of walking as exercise modality during VO<inf>2max</inf> testing. Sixteen participants (25±3 years, 172±9 cm, 69±15 kg, and VO<inf>2max</inf> 50±4 mL/kg/min) performed four incremental running- and walking VO<inf>2max</inf> tests (two tests in each condition) within 2-3 weeks. During the walking condition, the speed was set to 7 km/h, and the treadmill incline increased by 2.5% each min until exhaustion. Results from these tests were validated against a running protocol with 5.3% treadmill incline where the speed increased by 1 km/h each min until exhaustion. The walking protocol achieved similar reliability values for absolute and relative VO<inf>2max</inf> when compared to the running condition. No significant differences in VO<inf>2max</inf> were observed between test session 1 and 2 for any of the tests. Significantly higher absolute VO<inf>2max</inf> (3.39±0.77 vs. 3.50±0.84 L/min; trivial difference) were observed in the running versus walking condition, while no significant differences in relative VO<inf>2max</inf>, BLa or Borg were detected. CVs for absolute and relative VO<inf>2max</inf> between the analyzed exercise modalities were ~5%. Although the present participants achieved 2-3% lower VO<inf>2max</inf> when the walking test protocol was applied, walking seems to be a promising exercise-modality alternative during VO<inf>2max</inf> testing in clinical settings.

Validity and sensitivity of field tests' heart-rate recovery assessment in recreational football players.

We aimed at examining the criterion validity and sensitivity of heart-rate recovery (HRRec) in profiling cardiorespiratory fitness in male recreational football players in the untrained and trained status, using endurance field-tests. Thirty-two male untrained subjects (age 40 ± 6 years, VO2max 41.7 ± 5.7 ml·kg-1·min-1, body mass 82.7 ± 9.8 kg, stature 173.3 ± 7.4 cm) participated in a 12-week (2‒3 sessions per week) recreational football intervention and were tested pre- and post-intervention (i.e. untrained and trained status). The participants performed three intermittent field tests for aerobic performance assessment, namely Yo-Yo intermittent endurance level 1 (YYIE1) and level 2 (YYIE2) tests, and Yo-Yo intermittent recovery level 1 (YYIR1) test. VO2max was assessed by performing a progressive maximal treadmill test (TT) and maximal HR (HRmax) determined as the maximal value across the testing conditions (i.e., Yo-Yo intermittent tests or TT). HRRec was calculated as the difference between Yo-Yo tests' HRpeak or HRmax and HR at 30 s (HR30), 60 s (HR60) and 120 s (HR120) and considered as beats·min-1 (absolute) and as % of tests' HRpeak or HRmax values. Significant post-intervention improvements (p<0.0001) were shown in VO2max (8.6%) and Yo-Yo tests performance (23-35%). Trivial to small (p>0.05) associations were found between VO2max and HRRec (r = -0.05-0.27, p>0.05) across the Yo-Yo tests, and training status either expressed as percentage of HRpeak or HRmax. The results of this study do not support the use of field-test derived HRRec to track cardiorespiratory fitness and training status in adult male recreational football players.

Comparison of the Effects of Prebiotics and Synbiotics Supplementation on the Immune Function of Male University Football Players.

This study was conducted to compare the effects of long-term prebiotic and synbiotic supplementations on the immunosuppression of male football players after daily high-intensity training and a one-time strenuous exercise. A total of 30 male university student-athletes were recruited and randomly assigned to the prebiotic (PG, n = 15) or synbiotic group (SG, n = 15), receiving a prebiotic or synbiotic once per day for six weeks. Physiological assessments were conducted by a maximal oxygen uptake (VO2max) test and an exhaustive constant load exercise (75% VO2max test). Inflammatory cytokine and secretory immunoglobulin A (SIgA) were measured. VO2max, maximal heart rate (HRmax), and lactic acid elimination rate (ER) were used to evaluate aerobic capacity. Upper respiratory tract infection (URTI) complaints were evaluated using a questionnaire. URTI incidence and duration were significantly lower in the SG group than that in the PG group (p < 0.05). At baseline, SIgA and interleukin-1β (IL-1β) levels in the SG group (p < 0.01) as well as IL-1β and IL-6 in the PG group (p < 0.05) were significantly increased, and IL-4 concentration was markedly reduced in the PG group (p < 0.01). The concentrations of IL-4, IL-10 and transforming growth factor-β1 (TGF-β1) were significantly reduced in the PG and SG group immediately after the constant load exercise. Significantly decreased HRmax and enhanced ER (increased by 193.78%) were detected in the SG group, not in the PG group, during the constant load experiment (p < 0.05) and the recovery period (p < 0.01), respectively. However, VO2max value was not changed. These data suggest that synbiotic supplementation for six weeks has a more positive effect than prebiotics on the immune function and athletic performance of male university football players.

Validity and reliability of VO2-max testing in persons with Parkinson's disease

IntroductionDirect whole body assessment of maximal oxygen consumption (VO2-max test) is considered the gold standard when assessing cardiorespiratory fitness (VO2-max) in healthy people. VO2-max is also an important health and performance indicator for persons with Parkinson's disease (pwPD) and is often used when prescribing exercise and evaluating aerobic exercise interventions. However, no study has examined the content validity of the VO2-max test in pwPD as well as the test-retest reliability (i.e., day-to-day variation) in both the ON and OFF medication state. Therefore, the present study investigated the content validity and test-retest reliability of the VO2-max test in pwPD both ON and OFF medication. MethodsTwenty pwPD completed four VO2-max tests (two tests ON and two tests OFF medication), in a randomized order, separated by four to sixteen days. The first tests ON and OFF medication were used to assess content validity based on attainment of five pre-defined end-criteria (one primary and four secondary). Reliability was examined by intraclass correlation coefficients (ICC) and the day-to-day variation of the two ON and OFF medication tests. ResultsIn pwPD, 50% and 60% attained the primary end-criterion ON and OFF medication, respectively. A higher proportion (i.e., 70–90%) attained the secondary end-criteria both ON and OFF medication with no difference between medication states. Day-to-day variations were 1.2 and 1.8 ml O2/kg/min, while ICC2.1 were 0.97 (95%-CI: 0.92; 0.99) and 0.96 (95%-CI: 0.90; 0.98) ON and OFF medication, respectively. ConclusionThe VO2-max test has an acceptable content validity and excellent day-to-day reliability ON and OFF medication in pwPD.

The effects of eccentric arm crank training - A pilot study

Background&#x0D; Strength training plays an important role in a holistic training approach, not only for athletes but also for patients looking to (re)gain strength during rehabilitation. In the past few years, eccentric strength training has received increased attention as this type of training increases muscle strength more than conventional training methods (Douglas et al., 2017). Since eccentric strength training includes higher levels of mechanical tension and leads to greater exercise-induced muscle damage compared to concentric training, the training protocol should be implemented with caution and effects may appear after a longer recovery period (Douglas et al., 2017). Whereas lower body training has been studied extensively, only little data is available regarding eccentric strength training for the upper body, particularly in either wheelchair athletes or individuals with a spinal cord injury. We wanted to investigate if strength training on a specially designed eccentric arm crank ergometer (Krafttraining mittels exzentrischer Handkurbel, KREHA) can improve performance as well as the maximum strength of the upper body. In this pilot study, we investigated the feasibility of the training protocol in healthy individuals.&#x0D; Methods&#x0D; Thirteen healthy, physically active and strength training experienced participants (median [interquartile range] age 29 [5] years, nine women) participated in the study. The participants followed the eccentric arm crank training protocol besides their usual daily training routine. The performance tests and training at the KREHA were familiarized one week before the pretests (Pre) took place. The test battery consisted of a bench press (one-repetition maximum [1RM]), a Wingate test (peak and mean power) and a VO2max test (Wmax) on a regular arm crank ergometer, as well as grip strength and an upper arm circumference measurement. The training protocol consisted of 20 progressive training sessions on the KREHA. The training sessions were planned based on individual peak power using a double progression method for duration and intensity, and lasted between 8 to 14 minutes at an intensity of 20-50% of peak power. The sessions were spread over a maximum of 12 weeks, with no more than three sessions per week. Posttests consisted of the same test battery as the pretests and were scheduled 5-11 days (Post1) respectively four weeks (Post2) after the last training.&#x0D; Results&#x0D; The 1RM (39 [18] to 44 [18] kg), peak power (357 [143] to (360 [154] W) and mean power (263 [108] to 274 [135] W) improved over the training duration (Pre-Post1, p &lt; 0.05). Likewise, the upper arm circumference increased from 28.4 (3.5) to 29.5 (4.0) cm (p &lt; 0.05). 1RM, peak power and mean power remained higher four weeks after the last training (Pre vs. Post2, p &lt; 0.05). Grip strength remained similar at all time points (p = 0.2).&#x0D; Conclusions&#x0D; Participants were able to improve their aerobic and anaerobic performance between 1-4% as well as the maximum strength of the upper body by 13% through eccentric arm-crank training. In two future studies, the training concept will be investigated in wheelchair athletes and patients with a spinal cord injury.

How to Test the On-Ice Aerobic Capacity of Speed Skaters? An On-Ice Incremental Skating Test for Young Skaters.

Aerobic capacity is important for speed skaters to achieve good results in middle-long distance events. The technical characteristics of speed skating cause intermittent blood flow blockage in the lower limbs. Therefore, an athlete's aerobic capacity on ice may differ from that measured by cycling or running. Now, the on-ice aerobic capacity lacks methods for conducting aerobic capacity tests on ice. Objective: The objective of this study was to develop a method for measuring on-ice aerobic capacity for young athletes and to compare it with the VO2max test on cycling. Methods: This study established a test method for the on-ice aerobic capacity of young, high-level speed skaters with incremental load (on-ice incremental skating test, OIST) through expert interviews and literature review. In the first part, OIST was used to test the aerobic abilities of 65 youth professional speed skaters (51 males and 14 females) on ice and to explore the correlation with their specific performance. The second part compares the relationship between aerobic capacity on ice and aerobic capacity on bicycle of 18 young high-level male athletes. The third part establishes the regression formula of ice ventilation threshold heart rate. The OIST established in this study can evaluate the on-ice aerobic capacity of athletes from National Level and Level 1&2 in China. The athletes' on-ice aerobic capacity indicators were significantly lower than those of the cycling test. However, the values of absolute VO2max and absolute ventilatory threshold had a high correlation (R = 0.532, p < 0.05; R = 0.584, p < 0.05). The regression formula of ventilatory threshold heart rate on ice = 0.921 × HRmax (Cycling test) -9.243. The OIST established in this study meets the characteristics and requirements of the VO2max measurement method. The OIST seems to be able to better evaluate the aerobic capacity of athletes skating on ice. The indicators of maximum oxygen uptake and ventilation threshold in OIST were significantly lower than those in the aerobic cycling test, but there was a good correlation. The aerobic cycling test can be used as an important selection index of the ice aerobic capacity of speed skaters. The regression formula will provide an important basis for coaches to accurately monitor the intensity of ice training.

Sex differences in muscle SIRT1 and SIRT3 and exercise + weight loss effects on muscle sirtuins.

The sirtuins, SIRT1 and SIRT3, are involved in the control of cellular processes to maintain metabolic homeostasis. The purpose of this study was to determine the effects of a 6-month aerobic training + weight loss program and hyperinsulinemia on SIRT1 and SIRT3 expression in skeletal muscle and to compare their expression between men and women. Thirty-five adult men (n = 18) and postmenopausal women (n = 17), (X ± SEM, age: 61 ± 1 years, BMI: 31.3 ± 0.7 kg/m2) completed 6 months 3×/week of aerobic exercise and 1×/week dietary instruction to induce weight loss (EX + WL). Participants had a VO2max test, vastus lateralis muscle biopsies at baseline and 2 h into a hyperinsulinemic-euglycemic clamp, a total body dual-energy X-ray absorptiometry scan, and abdominal computed tomography scan. Skeletal muscle SIRT1, SIRT3, and PGC1-α mRNA expression were quantified by qRT-PCR. Skeletal muscle SIRT1 and SIRT3 mRNA expression are higher in women than men (P < 0.005). Body weight, body fat, and abdominal obesity decreased and VO2max and glucose utilization (M) increased after EX + WL (P < 0.001). Basal SIRT1 decreased following EX + WL (P < 0.05). This change in basal SIRT1 was not related to changes in VO2max, M or fat mass, nor was it different by gender. Insulin stimulation increased SIRT1 expression (P < 0.001) and PGC1-α expression (P < 0.01) following EX + WL (insulin-basal post). Sex differences in the levels of these sirtuins did not affect changes with EX + WL. Skeletal muscle SIRT1 decreases after a long-term combined exercise and weight loss program in middle-aged and older adults.

Implementing Modern Technology for Vital Sign Monitoring to Enhance Athletic Training and Sports Performance

(1) Background: Applying medical procedures to keep track of athletes’ metabolic health is a well-known behavior for increasing sports performance. This study’s primary goal was to examine whether implementing a health-screening routine using invasive and non-invasive methods in a mountain running training program can increase sports performance by obtaining a better rank in specific races. (2) Methods: Seven male mountain runners with good results at the international level participated in the research, which featured an initial and a final test. The initial test took place in March at the beginning of the competitive season, and the final test took place in September at the end of the annual training plan in 2021. The entire experiment used invasive tests, such as taking blood samples to perform blood biochemistry analysis, and non-invasive tests, such as mountain running races, determinations of VO2max, EKGs, urine biochemistry and NeuroTracker tests. (3) Results: Comparing the initial test with the final one from a statistical point of view, a significant improvement was found in the final test regarding the obtained results in most tests and, most importantly, the occupied position in the final general rank (p = 0.005). The main variations after effort were decreased Ca++ and increased Cl−, a low TGL level if the diet was inadequate, increased LDH and CPK strongly correlated with the skeletal muscle response, and only physiological changes were found in the EKG and urine summary. (4) Conclusions: The invasive and non-invasive tests applied in this study provided crucial information on the athletes’ health statuses, enabling the coach to adjust the training program in light of the findings in order to improve sports performance and avoid overexertion.

Effect of increased protein intake and exogenous ketosis on body composition, energy expenditure and exercise capacity during a hypocaloric diet in recreational female athletes.

Introduction: Since low body weight is an important determinant of success in many sports such as gymnastics, martial arts and figure skating, athletes can benefit from effective weight loss strategies that preserve muscle mass and athletic performance. The present study investigates the effects of increased protein intake and exogenous ketosis on body composition, energy expenditure, exercise capacity, and perceptions of appetite and well-being during a hypocaloric diet in females. Methods: Thirty-two female recreational athletes (age: 22.2 ± .5years; body weight: 58.3 ± .8kg; BMI: 20.8 ± .2kg·m-2) underwent 4 weeks of 30% caloric restriction and were randomized to receive either an increased daily amount of dietary protein (PROT, ∼2.0-2.2g protein·kg-1·day-1), 3 × 20g·day-1 of a ketone ester (KE), or an isocaloric placebo (PLA). Body composition was measured by DXA, resting energy expenditure (REE) by indirect calorimetry, exercise capacity during a VO2max test, appetite hormones were measured in serum, and perceptions of general well-being were evaluated via questionnaires. Results: The hypocaloric diet reduced body weight by 3.8 ± .3kg in PLA, 3.2 ± .3kg in KE and 2.4 ± .2kg in PROT (Ptime<.0001). The drop in fat mass was similar between treatments (average: 2.6 ± .1kg, Ptime<.0001), while muscle mass was only reduced in PLA and KE (average: .8 ± .2kg, Ptime<.05), and remained preserved in PROT (Pinteraction<.01). REE [adjusted for lean mass] was reduced after caloric restriction in PLA (pre: 32.7 ± .5, post: 28.5 ± .6kcal·day-1·kg-1) and PROT (pre: 32.9 ± 1.0, post: 28.4 ± 1.0kcal·day-1·kg-1), but not in KE (pre: 31.8 ± .9, post: 30.4 ± .8kcal·day-1·kg-1) (Pinteraction<.005). Furthermore, time to exhaustion during the VO2max test decreased in PLA (by 2.5 ± .7%, p < .05) but not in KE and PROT (Pinteraction<.05). Lastly, the perception of overall stress increased in PLA and PROT (p < .05), but not in KE (Pinteraction<.05). Conclusion: Increased protein intake effectively prevented muscle wasting and maintained exercise capacity during a period of caloric restriction in female recreational athletes. Furthermore, exogenous ketosis did not affect body composition, but showed its potential in weight management by preserving a drop in exercise capacity and REE and by improving overall stress parameters during a period of caloric restriction.

Type 2 Diabetes Related Mitochondrial Defects in Peripheral Mononucleated Blood Cells from Overweight Postmenopausal Women.

Type 2 diabetes (T2D) is a multisystem disease that is the subject of many studies, but the earliest cause of the disease has yet to be elucidated. Mitochondrial impairment has been associated with diabetes in several tissues. To extend the association between T2D and mitochondrial impairment to blood cells, we investigated T2D-related changes in peripheral mononucleated blood cells' (PBMCs) mitochondrial function in two groups of women (CTRL vs. T2D; mean age: 54.1 ± 3.8 vs. 60.9 ± 4.8; mean BMI 25.6 ± 5.2 vs. 30.0 ± 5), together with a panel of blood biomarkers, anthropometric measurements and physiological parameters (VO2max and strength tests). Dual-energy X-ray absorptiometry (DXA) scan analysis, cardio-pulmonary exercise test and blood biomarkers confirmed hallmarks of diabetes in the T2D group. Mitochondrial function assays performed with high resolution respirometry highlighted a significant reduction of mitochondrial respiration in the ADP-stimulated state (OXPHOS; -30%, p = 0.006) and maximal non-coupled respiration (ET; -30%, p = 0.004) in PBMCs samples from the T2D group. The total glutathione antioxidant pool (GSHt) was significantly reduced (-38%: p = 0.04) in plasma samples from the T2D group. The fraction of glycated hemoglobin (Hb1Ac) was positively associated with markers of inflammation (C-reactive protein-CRP r = 0.618; p = 0.006) and of dyslipidemia (triglycerides-TG r = 0.815; p &lt; 0.0001). The same marker (Hb1Ac) was negatively associated with mitochondrial activity levels (OXPHOS r = -0.502; p = 0.034; ET r = -0.529; p = 0.024). The results obtained in overweight postmenopausal women from analysis of PBMCs mitochondrial respiration and their association with anthropometric and physiological parameters indicate that PBMC could represent a reliable model for studying T2D-related metabolic impairment and could be useful for testing the effectiveness of interventions targeting mitochondria.

High fat diet improves metabolic flexibility during progressive exercise to exhaustion (VO2max testing) and during 5 km running time trials.

Recently we reported similar performances in both progressive tests to exhaustion (VO2max) and 5km running time trials (5KTT) after consuming low-carbohydrate, high-fat (LCHF) or high-carbohydrate, low-fat (HCLF) diets. Accordingly, we tested the null hypothesis that the metabolic responses during both tests would be similar across diets. In a randomized, counterbalanced, cross-over design, seven male athletes (VO2max: 61.9 ± 6.1 mL/kg/min; age: 35.6 ± 8.4 years; height: 178.7 ± 4.1 cm; mass: 68.6 ± 1.6 kg; body fat: 5.0 ± 1.3%) completed six weeks of LCHF (6/69/25% energy carbohydrate/fat/protein) and HCLF (57/28/15% energy carbohydrate/fat/protein) diets, separated by a two-week washout. Substrate utilization and energy expenditure were measured during VO2max tests and 5KTTs. The LCHF diet markedly increased fat oxidation and reduced carbohydrate oxidation, with no associated impairment in either the VO2max tests or the 5KTTs. Following the LCHF diet, athletes generated 50% or more of their energy requirements from fat at exercise intensities up to 90% VO2max and reached the crossover point for substrate utilization at ~85% VO2max. In contrast, following the HCLF diet, carbohydrate provided more than 50% of the total energy consumption at all exercise intensities. During the 5KTT, ~56% of energy was derived from fat following the LCHF diet whereas more than 93% of the energy came from carbohydrate following the HCLF diet. This study provides evidence of greater metabolic flexibility following LCHF eating and challenges the popular doctrines of "carbohydrate dependence" for high intensity exercise and the role dietary macronutrients play in human performance.

Recovery time variation during sprint interval training impacts amateur soccer players adaptations - a pilot study.

The objective of the present study was to investigate the selected performance adaptations of amateur soccer players to 2 different running-based sprint interval training (SIT) protocols with different recovery intervals and work-rest ratios (1:5 & 1:1). Twenty-three subjects (age 21.4 ± 1.1 years; height 175.4 ± 4.7 cm; body mass 69 ± 6.4 kg) participated in the study. Before the 6-weeks training period, participants completed 3-weeks of low-intensity training preparation. Subsequently, the pre-tests (anthropometric measurements, repeated sprint test [12 × 20-m with 30-s recovery intervals], Yo-YoIRT1 & Yo-YoIRT2 and treadmill VO2max test) were conducted. Thereafter, participants were randomly divided into 3 sub-groups (1 - SIT with 150 s recovery intervals [SIT150, n = 8]; 2 - SIT with 30 s recovery intervals [SIT30, n = 7]; and 3 - control group [CG, n = 8]). SIT150 and SIT30 training groups completed sprint interval training (2-days/week; 30-s all-out running, 6-10 repetition with 150 s recovery intervals for SIT150 and 30 s for SIT30 groups, respectively), a soccer match (1-day) and routine soccer training (3-days) per week. The CG attended only routine training sessions and the soccer-match (4-days). The study experiments and the trainings were conducted during off-season. Yo-YoIRT1, Yo-YoIRT2, and VO2max were significantly improved both in SIT30 and SIT150 (p < 0.05) groups. Yo-YoIRT1 and VO2max were also significantly improved in CG (p < 0.05). Both the SIT150 and SIT30 training were shown to improve Yo-YoIRT1, Yo-YoIRT2 and VO2max performance compared to the control group, nevertheless, SIT150 was more efficient in improving the Yo-YoIRT1, Yo-YoIRT2 than SIT30. The authors of this study suggest using SIT150 to induce more effective performance outputs in amateur soccer players.

Determining the standard levels of the time of appearance of the anaerobic threshold difference in terms of the application of the (VO2max) test with the (Fitmate pro) device for handball players

هدفت الدراسة إلى التعرف على المستويات المعيارية لزمن ظهور العتبة الفارقة اللاهوائية بدلالة أختبار (VO2max) في جهاز (Fitmate pro) ، وأستخدم الباحثان المنهج الوصفي على عينة من لاعبي أندية بغداد بكرة اليد للموسم الرياضي 2014 البالغ عددهم (62) لاعباً تم أختيارهم عمدياً ، وتم إجراء التجانس لهم في متغيرات مؤشر كتلة الجسم والعمرين الزمني والتدريبي وتم تطبيق اختبار أقصى أستهلاك للأوكسجين بمنظومة جهاز (Fitmate pro) عليهم ، لكون شريط النتائج لهذا الاختبار يحوي نتائج أختبار زمن ظهور العتبة الفارقة اللاهوائية ، وتم معالجة النتائج بإستخراج المعالم الإحصائية لهذا المؤشر وتحويل الدرجات الخام إلى الدرجات المعيارية (الزائية) ثم إلى الدرجات المعيارية المُعدلة ، ومن ثمَّ تبويب النتائج بمديات محددت والتي حققت (5) مستويات معيارية وكانت أستنتاجات الدراسة لا يمكن الإعتماد على نتائج تقنية الأجهزة الحديثة لقياس المؤشرات الفسيولوجية في تقويم حالة الرياضي ما لم تُعتَمَد المستويات المعيارية لنتائجها ، وأن الطريقة التي أستخدمها الباحثان حققت مستويات معيارية يُعتمد عليها في تقويم زمن ظهور العتبة الفارقة اللاهوائية بدلالة تطبيق أختبار (VO2max) بجهاز (Fitmate pro) لدى لاعبي كرة اليد .

Could Orthostatic Stress Responses Predict Acute Mountain Sickness Susceptibility Prior to High Altitude Travel? A Pilot Study.

Bellovary, Bryanne N., Andrew D. Wells, Zachary J. Fennel, Jeremy B. Ducharme, Jonathan M. Houck, Trevor J. Mayschak, Ann L. Gibson, Scott N. Drum, and Christine M. Mermier. Could orthostatic stress responses predict acute mountain sickness susceptibility before high altitude travel? A pilot study. High Alt Med Biol. 24:19-26, 2023. Purpose: This study assessed head-up tilt (HUT) responses in relation to acute mountain sickness (AMS)-susceptibility during hypoxic exposure. Materials and Methods: Fifteen participants completed three lab visits: (1) protocol familiarization and cycle maximal oxygen consumption (VO2max) test; (2) HUT test consisting of supine rest for 20 minutes followed by 70° tilting for ≤40 minutes; and (3) 6 hours of hypobaric hypoxic exposure (4,572 m) where participants performed two 30-minute cycling bouts separated by 1 hour at a 50% VO2max workload within the first 3 hours and rested when not exercising. During HUT, systolic blood pressure (SBP), diastolic blood pressure, heart rate (HR), and variability (blood pressure variability [BPV] and HR variability [HRV]) were measured continuously. The AMS scores were determined after 6 hours of exposure. Correlations determined relationships between HUT cardiovascular responses and AMS scores. Repeated-measures analysis of variance (ANOVA) assessed differences between those with and without AMS symptoms during HUT. Results: Higher AMS scores correlated with greater change in SBP variability (r = 0.52, p = 0.048) and blunted changes in HRV (root mean square of successive differences between normal heartbeats r = 0.81, p = 0.001, percentage of adjacent normal sinus intervals that differ by more than 50 milliseconds [pNN50] r = 0.87, p < 0.001) during HUT. A pNN50 interaction (p = 0.02) suggested elevated cardiac sympathetic activity at baseline and a blunted increase in cardiac sympathetic influence throughout HUT in those with AMS (pNN50 baseline: AMS = 26.2% ± 15.3%, no AMS = 51.0% ± 13.5%; first 3 minutes into HUT: AMS = 17.2% ± 19.1%, no AMS = 17.1% ± 10.9%; end of HUT: AMS = 6.2% ± 9.1%, no AMS 11.0% ± 10.0%). Conclusions: The results suggest autonomic responses via HUT differ in AMS-susceptible individuals. Changes in HRV and BPV during HUT may be a promising predictive measurement for AMS-susceptibility, but further research is needed for confirmation.

The effect of fatigue on the ankle and knee kinematics and kinetics in moderately and highly trained healthy non-rearfoot runners

ABSTRACT The aim of this study was to compare selected ankle and knee kinematic and kinetic parameters before and after a prolonged exhaustive treadmill run between two groups of non-rearfoot footstrike pattern (NRFP) runners with different training volumes. Twenty-eight habitual NRFP runners were assigned to two groups based on their weekly training volume (Highly-trained (HT)/Moderately-trained (MT)). Participants underwent the VO2max test, and the exhaustive treadmill ran with biomechanical analysis at the beginning and the end. The two-way RMANOVA was used to assess differences between the groups and the phase of the run. A paired t-test was used for post-hoc analysis in case of significant interaction effect. Kinetic results showed significant group effect for ankle plantarflexion moment and hip external rotation moment (end-phase: both greater in MT group). Kinematic results showed significant group×phase interaction for ankle dorsiflexion angle (end-phase: greater in MT group) at initial contact (IC), peak knee flexion angle (end-phase: greater in MT group), and peak ankle eversion angle during the stance phase (end-phase: greater in HT group). Additionally, a group effect was found for knee flexion angle at IC (end-phase: greater in HT group). This study suggests that HT healthy NRFP runners may have less potential for increased biomechanical risk of AT overload during an exhaustive run.

Longitudinal cardio-respiratory fitness prediction through wearables in free-living environments

Cardiorespiratory fitness is an established predictor of metabolic disease and mortality. Fitness is directly measured as maximal oxygen consumption (VO2max), or indirectly assessed using heart rate responses to standard exercise tests. However, such testing is costly and burdensome because it requires specialized equipment such as treadmills and oxygen masks, limiting its utility. Modern wearables capture dynamic real-world data which could improve fitness prediction. In this work, we design algorithms and models that convert raw wearable sensor data into cardiorespiratory fitness estimates. We validate these estimates’ ability to capture fitness profiles in free-living conditions using the Fenland Study (N=11,059), along with its longitudinal cohort (N = 2675), and a third external cohort using the UK Biobank Validation Study (N = 181) who underwent maximal VO2max testing, the gold standard measurement of fitness. Our results show that the combination of wearables and other biomarkers as inputs to neural networks yields a strong correlation to ground truth in a holdout sample (r = 0.82, 95CI 0.80–0.83), outperforming other approaches and models and detects fitness change over time (e.g., after 7 years). We also show how the model’s latent space can be used for fitness-aware patient subtyping paving the way to scalable interventions and personalized trial recruitment. These results demonstrate the value of wearables for fitness estimation that today can be measured only with laboratory tests.

Analysis of Cardiovascular Endurance of Futsal Athletes for Youth Development in Bengkulu City

This study aims to determine the level of cardiovascular endurance of young futsal athletes in the city of Bengkulu. This type of research is descriptive research. The research sample amounted to 30 people. The instrument used in this study was to use the Bleep Test/Multi-Stage which was carried out in the field with a length of 20 meters. The VO2 Max test was carried out by 30 Futsal Players for Youth Development in Bengkulu City. Based on the above results it can be concluded that the VO2 Max ability of the overall Youth Development Futsal Players in Bengkulu City carried out by 30 players in the Medium category as many as 16 players or with a percentage of 53%. With these results, it can be said that the cardiovascular results of Youth Development Futsal Players in Bengkulu City are in the medium category.Keywords: : Futsal Athletes, Cardiovascular Endurance