Anaerobic Threshold Research Articles

632. CAN CARDIOPULMONARY EXERCISE TESTING PREDICT NEOADJUVANT CHEMOTHERAPY TOXICITY IN OESOPHAGEAL ADENOCARCINOMA PATIENTS?

Abstract Background Cardiopulmonary exercise testing (CPET) is a method of assessing cardiopulmonary fitness. In the context of surgery, it is used to risk-stratify patients, allowing targeted prehabilitation to optimise comorbidities and fitness prior to surgery, and triage patients to the appropriate level of care after the operation. Various CPET-derived variables have been shown to be associated with short- and long-term outcomes after various surgery. In patients post-oesophagectomy, these variables are predictive of long-term survival. This study aimed to assess the use of this tool to predict neoadjuvant chemotherapy (NAC) related complications in patients receiving neoadjuvant FLOT prior to oesophagectomy. Methods All patients who underwent routine CPET during the staging process prior to NAC with FLOT and oesophagectomy in a single high-volume centre between September 2018 and January 2023 were included. Data were extracted from the unit’s contemporaneously maintained database. The Mann-Whitney U test was used to compare CPET variables in patients who completed NAC with FLOT fully versus those who did not finish NAC with FLOT due to acute chemotherapy toxicities. Results There were 129 patients who received neoadjuvant FLOT and had routine CPET performed during the defined study period. Six of those patients (4.7%) did not complete neoadjuvant chemotherapy due to acute chemotherapy toxicities but progressed to surgery. The median anaerobic threshold, VO2 peak, and VE/VCO2 among those who completed NAC were 14.2 ml/kg/min, 20.3 ml/kg/min, and 28, respectively, compared to 13.4 ml/kg/min, 19.7 ml/kg/min, and 31 in those who did not complete NAC (p=0.595, p=0.695, and p=0.160, respectively). Conclusion Although patients who received all four cycles of NAC with FLOT prior to oesophagectomy demonstrated CPET values indicating better base-line fitness than those who had to discontinue NAC due to acute chemotherapy toxicity, these differences did not reach the level of statistical significance. This study, therefore, did not demonstrate any predictive value of CPET in assessing the risk of incomplete NAC treatment prior to oesophagectomy.

Sigmoidal heart rate response pattern during exercise in patients with chronic heart failure.

Detailed heart rate (HR) response patterns during exercise in patients with heart failure (HF) and sinus rhythm remain uncertain. We screened consecutive patients with HF who underwent cardiopulmonary exercise tests at a large academic center from November 2013 to July 2023. HR response during exercise was statistically classified using logistic differential equation models. A total of 99 patients were included. Of them, 75 patients were assigned to "sigmoidal pattern" and the other 24 to "exponential pattern." Patients with the sigmoidal pattern were older and exhibited higher plasma B-type natriuretic peptide levels. Increases in HR and oxygen consumption (V̇o2)/kg up to the anaerobic threshold level were not different between both patterns. However, beyond the threshold, the sigmoidal pattern group showed no further increase in HR and significantly lower V̇o2/kg than their counterparts (interactions for P < 0.001). HR response during exercise in patients with heart failure and sinus rhythm was categorized into two unique groups: sigmoidal and exponential patterns. More detailed clarification of the sigmoidal pattern, potentially indicating sinus node dysfunction, should offer new clinical insights for chronotropic incompetence.NEW & NOTEWORTHY Heart rate response patterns can be classified into two groups among patients with chronic heart failure reaching maximal exertion: sigmoidal and exponential.

Comparison of Cardiopulmonary Exercise Test Variables to Predict Adverse Events in Patients with Heart Failure.

Given the rising burden of heart failure (HF), stratification of patients at increased risk for adverse events is critical. We aim to compare the predictive value of various maximal and submaximal cardiopulmonary exercise test (CPET) variables for adverse events in patients with HF. 237 patients with HF (66 [58-73] years, 30% women, 70% HF with reduced ejection fraction) completed a CPET and had five years of follow-up. Baseline characteristics and clinical outcomes (all-cause mortality, major adverse cardiovascular events, and cardiovascular-related hospitalization) were extracted from electronic patient files. Receiver operating characteristics curves for maximal (e.g. peak VO2) and submaximal CPET variables (e.g. VE/VCO2 slope, cardiorespiratory optimal point (COP), VO2 at anaerobic threshold) were compared using the Akaike Information Criterion (AIC) method, whereas their calibration was assessed. 103 participants (43%) reached the composite endpoint, and 55 (23%) died. Percent predicted peak VO2 was the best predictor for adverse outcomes (AIC: 302.6) followed by COP (AIC: 304.3), and relative peak VO2 (mL/(kg·min), AIC: 304.4). Relative peak VO2 (AIC: 217.1) and COP (AIC: 224.4) were also among the three best predictors for mortality, together with absolute peak VO2 (ml/min, AIC: 220.5). A good calibration between observed and predicted event rate was observed for these variables. Percent predicated and relative peak VO2 had the best predictive accuracy for adverse events and mortality, but the submaximal COP had a non-inferior predictive accuracy for adverse events in patients with HF. These findings highlight the potential of submaximal exercise testing in patients with HF.

Exercise-Induced Cardiac Troponin I Elevation Is Associated With Regional Alterations in Left Ventricular Strain in High-Troponin Responders.

The implications of exercise-induced cardiac troponin elevation in healthy individuals are unclear. This study aimed to determine if individuals with a high exercise-induced cardiac troponin I (cTnI) response have alterations in myocardial function following high-intensity endurance exercise compared with normal-cTnI responders. Study individuals were recruited from previous participants in a 91-km mountain bike cycling race (the North Sea Race) and were classified as high- (n=34) or normal-cTnI responders (n=25) based on maximal cTnI values after the recruitment race. The present study exposed all participants to 2 prolonged high-intensity exercises: a combined lactate threshold and cardiopulmonary exercise test and repeated participation in the North Sea Race. Echocardiography was performed before, immediately after, and 24 hours following exercise. All study individuals (n=59) had normal coronary arteries, and were aged 51±10 years; 46 (74%) were men. There were no differences in baseline characteristics between the high- and normal-cTnI responders. Maximal cTnI levels 3 hours after exercise were significantly higher in the high- compared with normal-cTnI group (P<0.001-0.027). Following exercise, there were no differences in global ventricular function between the 2 groups. In contrast, high-cTnI responders had significantly lower regional strain in the anteroseptal segments following exercise, with more profound changes after the race. High-cTnI responders had lower anteroseptal segmental strain shortly after exercise than normal-cTnI responders. However, there were no permanent alterations in myocardial strain, indicating no short- or long-term adverse consequences of these exercise-induced alterations in myocardial function. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02166216.

Sweat lactate sensor for detecting anaerobic threshold in heart failure: a prospective clinical trial (LacS-001)

A simple method for determining the anaerobic threshold in patients with heart failure (HF) is needed. This prospective clinical trial (LacS-001) aimed to investigate the safety of a sweat lactate-monitoring sensor and the correlation between lactate threshold in sweat (sLT) and ventilatory threshold (VT). To this end, we recruited 50 patients with HF and New York Heart Association functional classification I–II (mean age: 63.5 years, interquartile range: 58.0–72.0). Incremental exercise tests were conducted while monitoring sweat lactate levels using our sensor. sLT was defined as the first steep increase in lactate levels from baseline. Primary outcome measures were a correlation coefficient of ≥ 0.6 between sLT and VT, similarities as assessed by the Bland–Altman analysis, and standard deviation of the difference within 15 W. A correlation coefficient of 0.651 (95% confidence interval, 0.391–0.815) was achieved in 32/50 cases. The difference between sLT and VT was −4.9 ± 15.0 W. No comparative error was noted in the Bland–Altman plot. No device-related adverse events were reported among the registered patients. Our sweat lactate sensor is safe and accurate for detecting VT in patients with HF in clinical settings, thereby offering valuable additional information for treatment.

Physiological Demands of Competitive Collegiate Dance.

Seifert Gonzales, AM and Stenson, MC. Physiological demands of competitive collegiate dance. J Strength Cond Res 38(9): e503-e509, 2024-Competitive collegiate dance combines elements of gymnastics and acrobatics with more traditional styles, such as ballet, jazz, and modern dance. Assessing the physiological demands and identifying clear measures of intensity and duration of such dance provide a framework for planning the competitive season and developing strength and conditioning programs. This study examined the blood lactate (BL), heart rate (HR), and ratings of perceived exertion (RPE) of 14 well-trained female dancers on a competitive collegiate dance team. Subjects completed a treadmill test to determine their lactate threshold (LT) and then performed a 120-second choreographed jazz dance routine in cumulative 30-second segments, during which physiological markers were measured. All subjects exceeded their individually determined LT values by 90 seconds into the dance routine. A moderate (rs = 0.53; p < 0.001) positive correlation was observed between HR and RPE, as was a strong (rs = 0.70; p < 0.001) positive correlation between BL and RPE. Subjects worked at or above LT for much of the 120-second jazz dance routine, indicating that competitive collegiate dance is physiologically demanding and highly anaerobic. Understanding the physiological demands of competitive collegiate dance allows strength and conditioning professionals to develop, monitor, and adjust training parameters, which will aid in minimizing injury and maximizing competitive performance in collegiate dancers.

Lactate threshold evaluation in swimming using a sweat lactate sensor: A prospective study.

Since assessing aerobic capacity is key to enhancing swimming performance, a simple and widely applicable technology should be developed. Therefore, we aimed to noninvasively visualize real-time changes in sweat lactate (sLA) levels during swimming and investigate the relationship between lactate thresholds in sweat (sLT) and blood (bLT). This prospective study included 24 university swimmers (age: 20.7s±1.8years, 58% male) who underwent exercise tests at incremental speeds with or without breaks in a swimming flume to measure heart rate (HR), bLT, and sLT based on sLA levels using a waterproof wearable lactate sensor attached to the dorsal upper arm on two different days. The correlation coefficient and Bland-Altman methods were used to verify the similarities of the sLT with bLT and personal performance. In all tests, dynamic changes in sLA levels were continuously measured and projected onto the wearable device without delay, artifacts, or contamination. Following an initial minimal current response, with increasing speed the sLA levels increased substantially, coinciding with a continuous rise in HR. The speed at sLT strongly correlated with that at bLT (p<0.01 and r=0.824). The Bland-Altman plot showed a strong agreement (mean difference: 0.08±0.1m/s). This prospective study achieved real-time sLA monitoring during swimming, even with vigorous movement. The sLT closely approximated bLT; both were subsequently validated for their relevance to performance.

The Influence of Acute Oral Lactate Supplementation on Responses to Cycle Ergometer Exercise: A Randomized, Crossover Pilot Clinical Trial.

The purpose of this study was to investigate the potential ergogenic effects of an oral lactate supplement. For this double-blind, randomized, placebo-controlled crossover design, fifteen recreational exercisers (nine males, six females) ingested a placebo or a commercially available lactate supplement prior to cycle ergometer exercise. Primary outcomes included peak oxygen uptake (VO2peak; via indirect calorimetry), VO2 at the ventilatory threshold, and work rate at the lactate threshold (arterialized venous blood from a heated hand) determined during incremental exercise to fatigue, and power output during a 20-min cycling time trial. Compared with placebo, the oral lactate supplement (19 ± 1 mg/kg body mass) did not influence VO2peak (placebo: 44.3 ± 7.8 vs. oral lactate: 44.3 ± 7.1 mL/kg/min (mean ± SD); p = 0.87), VO2 at the ventilatory threshold (placebo: 1.63 ± 0.25 vs. oral lactate: 1.65 ± 0.23 L/min; p = 0.82), or work rate at the lactate threshold (placebo: 179 ± 69 vs. oral lactate: 179 ± 59 W; p = 0.41). Throughout the 20-min time trial, the work rate was slightly greater (4%) with oral lactate (204 ± 41 W) compared with placebo (197 ± 41 W; main effect of treatment p = 0.02). Collectively, these data suggest that this commercially available lactate supplement did not acutely influence the physiological responses to incremental cycle ergometer exercise but elicited a modest ergogenic effect during the short-duration time trial.

The validity and reliability of quadriceps twitch force as a measure of skeletal muscle fatigue while cycling.

The measurement of skeletal muscle fatigue in response to cycling exercise is commonly done in isometric conditions, potentially limiting its ecological validity, and creating challenges in monitoring the time course of muscle fatigue across an exercise bout. This study aimed to determine if muscle fatigue could be reliably assessed by measuring quadriceps twitch force evoked while pedaling, using instrumented pedals. Nine participants completed three laboratory visits: a step incremental test to determine power output at lactate threshold, and on separate occasions, two constant-intensity bouts at a power output 10% above lactate threshold. Femoral nerve electrical stimulation was applied to elicit quadriceps twitch force both while pedaling (dynamic) and at rest (isometric). The test-retest reliability of the dynamic twitch forces and the agreement between the dynamic and isometric twitch forces were evaluated. Dynamic twitch force was found to have excellent reliability in an unfatigued state (intraclass correlation coefficient (ICC)=0.920 and mean coefficient of variation (CV)=7.5%), and maintained good reliability at task failure (ICC=0.846 and mean CV=11.5%). When comparing dynamic to isometric twitch forces across the task, there was a greater relative decline in the dynamic condition (P=0.001). However, when data were normalized to the 5min timepoint when potentiation between conditions was presumed to be more similar, this difference disappeared (P=0.207). The reliability of this method was shown to be commensurate with the gold standard method utilizing seated isometric dynamometers and offers a new avenue to monitor the kinetics of muscle fatigue during cycling in real time.

Effectiveness of maximum, explosive and combined strength training on endurance runners performance indicators: a systematic review and meta-analysis

Objective: This study aimed to analyze the effect of practicing maximum strength (MAX), explosive strength (EXP), or both combined (COMB) on seven runners’ performance indicators: vertical jump (VJ), one-repetition maximum squat (1RM), peak velocity/peak running speed (PV), lactate threshold (LT), middle-distance time trial (TT), maximum oxygen consumption (VO2max), and running economy (RE). Methods: A systematic review (Scopus, Web of Science, Sports Discuss, PubMed) with meta-analysis was conducted following PRISMA standards. Inclusion criteria (PICOS) were: Recreational or well-trained athletes aged 18-45 performing concurrent training for at least five weeks. The search terms used were related to different types of strength/endurance and participants’ age and sports modality. Twenty manuscripts were selected, and quality assessed with PEDro. Results: MAX training is more effective than EXP and COMB in improving VJ, 1RM, and PV, while COMB is more effective than MAX and EXP to enhance TT. MAX is more effective than EXP in improving LT. Concurrent workouts do not provide additional benefits to VO2max. It is unknown which strength modality (MAX, EXP, or COMB) is more effective in improving RE. Conclusion: Concurrent training is more effective than single-mode endurance training for enhancing specific performance variables in adult endurance runners. Middle- and long-distance runners may consider incorporating MAX training to target specific goals (i.e., improving VJ, 1RM, LT, PV) while utilizing COMB training to enhance TT. Certain variables may benefit from EXP. New randomized controlled trials are required to confirm these findings. Keywords: endurance, running, concurrent training, maximum strength, explosive strength

Effects of high-intensity interval and moderate-intensity continuous training on the anaerobic threshold of highly trained athletes in endurance sports: a systematic review with meta-analysis.

The anaerobic threshold (AT) is an important physiological index used as a parameter for predicting performance and evaluating adaptations induced by training. The aim of this study was to carry out a systematic literature review to survey the randomized studies that compared the effects of high-intensity interval training (HIIT) with the effects of moderate intensity continuous training (MICT) on the anaerobic threshold of highly trained athletes in endurance sports. The following databases were searched: MEDLINE, Embase, Cochrane Wiley, PubMed, SPORTDiscus, Web of Science, and ProQuest for randomized trials. The search terms covered the areas of HIIT and MICT. This study was registered in the International Prospective Register of Systematic under the number CRD42020155474. Three studies were included for the qualitative and quantitative synthesis, totaling 72 participants, of whom 28 belonged to the MICT group and 44 to the HIIT group. The summary result showed that HIIT promotes greater adaptation in the AT of highly trained athletes compared to continuous training (ES=0.73; 95% CI: 0.25-1.21); however, the certainty of evidence evaluated by the GRADE method is low and heterogeneity is high (I2=82%; P<0.01).

Exercise testing in clinical context: Reference ranges for interpreting anaerobic threshold as an outcome for congenital heart disease patients

BackgroundChange in the oxygen consumption (VO2) at the ventilatory anaerobic threshold (VAT) is an important outcome in research studies of children with congenital heart disease (CHD). The range of values reported by different raters for any given VAT is needed to contextualize a change in VAT in intervention studies. MethodsSixty maximal cardiopulmonary exercise tests (CPET) for CHD patients 8–21 years old were independently reviewed by six exercise physiologists and four pediatric cardiologists. For each of the unique rater pairs for the 60 CPETs, the absolute difference in VAT was calculated and displayed on a histogram to demonstrate the distribution of inter-rater variability. This method was repeated for subgroups of test modality (cycle/treadmill), patient factors (diagnoses, exercise capacity), and rater factors (cardiologist/physiologist, years of experience). ResultsRater agreement was good with an intraclass correlation coefficient of 0.79–0.91 but the distribution of differences was broad. The median difference was 2.7 % predicted peak VO2 (60 mL/min, 1.0 mL/kg/min), the 75th percentile was 6.4 % (140 mL/min, 2.5 mL/kg/min), and the 95th percentile was 16.3 % (421 mL/min, 6.5 mL/kg/min). Distributions were similar for CPET modality and years of rater experience, but differed for other factors. ConclusionsThe baseline distribution of reported VAT is relatively broad, varied by units, and was not explained by differences in rater experience or test modality, but varies by patient factors. When evaluating clinical relevance, a change in the VO2 at VAT in response to an intervention of <6.5 % predicted falls within the majority (75th percentile) of expected variability and should be interpreted with caution.

Usefulness of Inter-Hospital Heart Team Conference Based Collaborative Outpatient Cardiac Rehabilitation in Patients with Cardiovascular Disease.

An inter-hospital heart team conference based collaborative follow-up (FU) may facilitate outpatient cardiac rehabilitation (CR) programs, especially in hospitals without an outpatient CR center. Consecutive 145 patients with cardiovascular disease who received inpatient treatment at Yamagata University Hospital were divided into collaborative (n = 76) and same-hospital (n = 69) FU groups. In the collaborative FU group, patients received outpatient care at a university hospital and outpatient CR at different hospitals. In the same-hospital FU group, patients received outpatient care and outpatient CR at the same hospital other than the university hospital. The collaborative FU group held monthly 60-minute inter-hospital heart team conferences with CR specialists. No cardiovascular accidents occurred during the outpatient CR program in either group. Peak oxygen uptake VO2, anaerobic threshold, brain natriuretic peptide level, and left ventricular ejection fraction significantly improved in both groups. Kaplan-Meier analysis revealed no significant difference in prognosis between the collaborative and same-hospital FU groups (P = 0.246). Of the patients who had collaborative CR programs, 29 (38.2%) patients (37 consultations) were discussed at an inter-hospital heart team conference. Eighteen (48.6%) consultations were for issues related to continuing outpatient CR programs. Collaborative FU was as useful as same-hospital FU in terms of safety, efficacy, and prognosis in patients with cardiovascular disease. We conclude that regular inter-hospital heart team conferences are useful for facilitating collaboration among outpatient CR programs.

A Comparative Study of Body Composition and Aerobic Capacity between Water and Land Exercise Walking in Male College Students with Mild Obesity

This study explores the impact of water and land fitness walking on the body composition and aerobic capacity of mildly obese male college students. Employing a randomized controlled trial, 36 mildly obese male college students were divided into a water group, a land group, and a non-intervention control group. Following a 4-week exercise intervention, dual-energy X-ray absorptiometry and power bicycle tests assessed body composition and aerobic capacity. The results revealed that both the water and land groups significantly enhanced relative maximum oxygen uptake and lactate threshold, with the water group showing greater improvement. Additionally, water fitness walking significantly reduced body composition indicators including body weight, BMI, waist circumference, waist-to-hip ratio, and thigh circumference. However, there were no significant changes in height, chest circumference, muscle mass, and bone density. The research indicates that water fitness walking uniquely enhances aerobic exercise capacity and body composition, offering a scientific foundation for college students to select effective weight loss exercise methods.

Acute aerobic exercise and creative thinking: comparison of transient hypofrontality state and strength model of self-controls’ theoretical predictions

Creativity is a high-level cognitive activity that can" be affected by acute aerobic exercise. This paper aims to determine how acute aerobic exercise intensities may influence aspects of divergent and convergent creative thinking. In this regard, to give an insight into the results, the predictions of the transient hypofrontality thesis and the strength model of self-control have been taken into consideration. Ninety-three healthy male college students (age = 21.18 ±1.73 years) were randomly assigned to anaerobic threshold intensity (%85 HRmax, n = 31), low intensity (%60 HRmax, n = 31), and control (n = 31) groups Participants performed divergent (Alternate Uses Task) and convergent (Raven's Advanced Progressive Matrices Test) creative thinking tasks before, during, and after cessation of two anaerobic thresholds and low intensities and control conditions. For the divergent creative thinking, flexibility and fluency performances during and after cessation of exercise in anaerobic threshold and low-intensity groups were improved in comparison to the control group.These results were consistent with the transient hypofrontality thesis and inconsistent with the strength model of self-control pre-dictions. In contrast, the performance of convergent creative thinking was relatively stable during and after cessation of exercise in anaerobic threshold and low-intensity groups which was inconsistent with both the transient hypofrontality thesis and the strength model of self-control predictions. The findings suggest that theoretical predictions of transient hypofrontality thesis are more adaptable with literature than the strength model of self-control to consider the exercise-creative processes relationship and further study of the issue would be of interest. Key words: Cognition, Convergent, Creativity, Divergent, Self-depletion, Physical Activity

Effects of Endurance Training on Antioxidant and Hormonal Status in Peripheral Blood of Young Healthy Men.

(1) Background: Physical activity may cause an imbalance in the major functions of the human body. This study aimed to investigate the effects of endurance running training on the parameters of the antioxidant defense system (SOD, CAT, GPx, GR, GSH), LPO (malondialdehyde, MDA), and stress hormones (A, NA) in young healthy, previously untrained men. (2) Methods: The training program was as follows: 8 weeks of running, three times per week; the duration of a single session was 30-70 min, the intensity was twice a week in the so-called extensive endurance zone, and once a week in the anaerobic threshold zone. Blood samples were collected from the subjects, before and after the running program. (3) Results: The training program resulted in a significant increase in maximal oxygen consumption (p < 0.001). The activities of SOD, GPx, and GR also increased significantly (p < 0.05, p < 0.01, and p < 0.05, respectively), while CAT activity and GSH and MDA concentrations remained unchanged. The concentration of A decreased (p < 0.05), while the NA concentration increased significantly (p < 0.05). SOD, GPx, GR, and NA positively correlated with VO2max (p < 0.05, p < 0.001, p < 0.01, p < 0.05, respectively), while a negative correlation was detected between A and VO2max (p < 0.05). (4) Conclusions: These results indicate that there is no persistent oxidative stress in response to the applied 8-week running program, probably due to exercise-induced protective alterations in the antioxidant defense system. Furthermore, adaptations occurred at the hormonal level, making the organism more ready for a new challenge.

Sphingolipid and Trimethylamine-N-Oxide (TMAO) Levels in Women with Obesity after Combined Physical Training.

Obesity causes metabolic changes, such as the development of cardiovascular diseases. Moreover, physical exercise promotes protection against these diseases. Thus, the objective of the present study was to evaluate whether combined physical training can improve the metabolic system of women with obesity, reducing plasma concentrations of trimethylamine N-oxide (TMAO) and sphingolipids, regardless of weight loss. Fourteen obese women (BMI 30-40 kg/m2), aged 20-40 years, sedentary, were submitted to 8 weeks of combined physical training (strength and aerobic exercises). The training was performed three times/week, 55 min/session, at 75-90% maximum heart rate. All participants were evaluated pre- and post-exercise intervention, and their body composition, plasma TMAO, creatinine, lipid profile, and sphingolipid concentrations were recorded. Maximum oxygen consumption (VO2max), Speed lactate threshold 1 (SpeedLT1), and Speed lactate threshold 2 (SpeedLT2) evaluated physical performance. Results: After combined exercise, it did not change body composition, but TMAO, total cholesterol, and sphingolipid concentrations significantly decreased (p < 0.05). There was an increase in physical performance by improving VO2max, SpeedLT1, and SpeedLT2 (p < 0.05). The combined physical exercise could induce cardiovascular risk protection by decreasing TMAO in obese women, parallel to physical performance improvement, independent of weight loss.

Endurance training volume cannot entirely substitute for the lack of intensity.

Very low intensity endurance training (LIT) does not seem to improve maximal oxygen uptake. The purpose of the present study was to investigate if very high volume of LIT could compensate the lack of intensity and is LIT affecting differently low and high intensity performances. Recreationally active untrained participants (n = 35; 21 females) cycled either LIT (mean training time 6.7 ± 0.7 h / week at 63% of maximal heart rate, n = 16) or high intensity training (HIT) (1.6 ± 0.2 h /week, n = 19) for 10 weeks. Two categories of variables were measured: Low (first lactate threshold, fat oxidation at low intensity exercise, post-exercise recovery) and high (aerobic capacity, second lactate threshold, sprinting power, maximal stroke volume) intensity performance. Only LIT enhanced pooled low intensity performance (LIT: p = 0.01, ES = 0.49, HIT: p = 0.20, ES = 0.20) and HIT pooled high intensity performance (LIT: p = 0.34, ES = 0.05, HIT: p = 0.007, ES = 0.48). Overall, very low endurance training intensity cannot fully be compensated by high training volume in adaptations to high intensity performance, but it nevertheless improved low intensity performance. Therefore, the intensity threshold for improving low intensity performance is lower than that for improving high intensity performance. Consequently, evaluating the effectiveness of LIT on endurance performance cannot be solely determined by high intensity performance tests.

The influence of foot muscles exercises and minimalist shoes on lactate threshold velocity in long-distance amateur runners: a randomized controlled trial

The exercises of plantar foot muscles may have beneficial effects on the performance of the lower extremity muscles. The aim of this study was to compare two methods of foot muscle strengthening: direct short foot muscle exercises and indirect activation through training in minimalist footwear in regard to influence on lactate threshold velocity in long-distance runners. 55 recreational runners aged 21–45 years took part in that study. They were randomly divided into 2 groups: Group 1 (n = 25) with short foot muscle exercises, and Group 2 (n = 30) with training in minimalist shoes. The progressive running test was performed to determine heart rate (HR) and running velocity corresponding to lactate threshold (VLT). Two-way ANOVA was used to determine the significance of the differences regarding the evaluated variables. After the 8-week training program, higher values of VLT were observed in both groups. This change was significant only in Group 1 (p < 0.05). In Group 2, the higher value was noted but the changes were non-significant. Strengthening of the short foot muscles may improve lactate threshold velocity which is connected with running performance. Considering the obtained results, it is worth contemplating the implementation of these methods in the training of long-distance runners.

Cardiac rehabilitation in children and adolescents with long QT syndrome: the RYTHMO’FIT pilot study

BackgroundTo assess the feasibility, acceptability, safety, and short-term benefits of a tailored cardiac rehabilitation program for children and adolescents with long QT syndrome (LQTS).MethodsEight participants, aged between 6 and 18, with a positive LQTS genotype and impaired cardiorespiratory fitness, were enrolled in a 12-week centre-based cardiac rehabilitation program. The program included supervised exercise training group sessions (aerobic, resistance, and outdoor activities) and patient education workshops. Feasibility, acceptability, and safety of the program were prospectively monitored. Feedback from the parents, children, and professionals involved was collected from qualitative interviews. Short-term effects on cardiorespiratory fitness, muscle fitness, physical activity, and health-related quality of life (HRQoL) were measured between baseline and the end of the program.ResultsRetention (88% with one participant dropping out) and adherence (79%) rates were good, and no cardiac events occurred during the 12-week intervention period. Participants, parents, and healthcare professionals expressed a high level of satisfaction with the program. A significant increase between the beginning and the end of the program was observed for ventilatory anaerobic threshold (21.7±5.2 vs. 28.7±5.1 mL/kg/min, P=0.01, effect size=0.89), grip strength, (18±5.3 Kg vs. 20±4.7 Kg, P=0.02, effect size=0.90), lower limb explosive strength (142±36.5 cm vs. 148±24 cm, P=0.02, effect size=0.90), and parent-reported physical health dimension of HRQoL (65.6±9.75 vs. 84.4±20.35, P=0.03, effect size=0.87).ConclusionsA 12-week tailored centre-based cardiac rehabilitation program was feasible, acceptable, and safe for children with LQTS. Cardiac rehabilitation for children with LQTS presents a new approach aligned with secondary prevention in youth with cardiac diseases.Trial registrationThe trial was registered at Clinicaltrials.gov (NCT05964322, registration date: 27/07/2023).