Submaximal Heart Research Articles

Determination of the real training load based on monitoring of K1 kickboxing bouts

Background: Kickboxing is a combat sport in which scientific observations are regularly made to improve the quality of the training process. Heart rate monitoring is the basic form of the evaluation of training load and diagnosing the athlete's capabilities. The purpose of this study was to determine training load based on heart rate measurements in K1 kickboxers. Methods: The study was conducted on 18 kickboxers, with HR recorded over a 3-round kickboxing fight. HRmax level was calculated for each athlete according to the most recent formula. Based on these data, the percentage training load was determined according to the needs arising from the training periodization. Results: The results of the study showed that training of K1 kickboxers is based primarily on submaximal heart rates, which increase with each round of the bout (p<0.001). Conclusions: The training load for a K1 kickboxing bout based on maximum heart rate should be 95.44% HRmax in the first round, 96.23% HRmax in the second, and 97.01% HRmax in the round..

Strain Magnitude Assessed at Rest and During Stress Echocardiography in Patients with Normal Coronary Flow Reserve

Background Coronary flow and myocardial contractile performance assessed by strain magnitude increase during a dobutamine stress echocardiogram (DSE). Normal coronary flow reserve (CFR) can be attained upon completion of a DSE at age-predicted maximum heart rate (HR) (HRmax = 220 – age)] or submaximal HR [(0.85) HRmax] or before completion (early CFR). Objective To ascertain the association between delta strain and HR in patients with early normal CFR. Methods This prospective study included patients whose normal CFR was obtained [...]

Factors Affecting the Exercise Capacity in Pediatric Primary Hypertension.

PurposeExercise training is crucial to the early intervention of pediatric primary hypertension (PHT). However, much less is known about exercise capacity in this disease. This work investigated the exercise capacity in pediatric PHT and analyzed the factors affecting exercise capacity.MethodsThe study enrolled children with PHT at the Children's Hospital Capital Institute of Pediatrics between July 2017 and July 2020. The Bruce protocol of the treadmill exercise test (TET) was used to assess exercise capacity. Multivariate ordinal logistic regression and generalized linear models were used to analyze factors affecting exercise capacity.ResultsOf 190 patients, 146 (76.8%) were male, and the median age was 13 (11, 14). Most children accomplished TET and achieved the submaximal heart rates (189 [99.5%]). Children with lower resting diastolic blood pressure (DBP) and 24 h average diastolic blood pressure (ADBP) could achieve a TET stage of 6 or more, whereas children with higher DBP and ADBP could only achieve a TET stage of 3 (P all < 0.05). Children with lower DBP and 24 h ADBP were also associated with greater metabolic equivalents (METs; r = −0.237, r = −0.179, P all < 0.05). The completion of TET stages was negatively associated with female (OR = 0.163), younger age (OR = 1.198), greater body mass index (BMI, OR = 0.921), and higher 24 h ADBP (OR = 0.952, P all < 0.05). In addition, METs were negatively associated with female (β = −1.909), younger age (β = 0.282), greater BMI (β = −0.134), and higher 24 h ADBP (β = −0.063, P all < 0.05).ConclusionsExercise capacity was impaired among pediatric PHT patients. Female gender, younger age, greater BMI, and higher 24 h ADBP are independently associated with the exercise capacity in pediatric PHT. These findings may help developing scientific exercise prescriptions for pediatric PHT.

Modelling 5-km Running Performance on Level and Hilly Terrains in Recreational Runners.

Simple SummaryIn the last decades, performance models have helped to comprehend the mechanisms involved in long-term physical performance. In addition, predictive models have aided in the evaluation and prescription of physical training. Here, we tested the hypothesis that physiological assessments under inclined conditions would better explain hilly running performance. We also checked the predictive role of running biomechanical, anthropometric, and neuromuscular factors. Velocity associated with maximal oxygen consumption was more predictive when assessed in inclined conditions (7%) than testing at level. Secondarily, ventilatory thresholds submaximal heart rate improved the performance models at hilly and level conditions. Spatiotemporal, strength, and anthropometric factors were not determinants of performance. Physiological assessments in inclined conditions predict 5-km running performance at hilly terrains in higher degree than evaluations at level in endurance runners.Incline and level running on treadmills have been extensively studied due to their different cardiorespiratory and biomechanical acute responses. However, there are no studies examining the performance determinants of outdoor running on hilly terrains. We aimed to investigate the influence of anthropometrics, muscle strength, and cardiorespiratory and gait spatiotemporal parameters during level (0%) and inclined (+7%) running on performance in level and hilly 5-km races. Twenty male recreational runners completed two 5-km outdoor running tests (0% vs. +7% and −7%), and two submaximal (10 km·h−1) and incremental treadmill tests at 0 and 7% slopes, after complete laboratory evaluations. The velocity at maximal oxygen consumption (VO2max) evaluated at 7% incline and level treadmill running were the best performance predictors under both hilly (R2 = 0.72; p < 0.05) and level (R2 = 0.85; p < 0.01) conditions, respectively. Inclusion of ventilatory and submaximal heart rate data improved the predictive models up to 100%. Conversely, none of the parameters evaluated in one condition contributed to the other condition. The spatiotemporal parameters and the runners’ strength levels were not associated to outdoor performances. These results indicate that the vVO2max evaluated at similar slopes in the lab can be used to predict 5-km running performances on both level and hilly terrains.

Factors Associated with Age-Related Declines in Cardiorespiratory Fitness from Early Adulthood Through Midlife: CARDIA.

This study aimed to describe maximal and submaximal cardiorespiratory fitness from early adulthood to midlife and examine differences in maximal fitness at age 20 yr and changes in fitness overtime by subcategories of sociodemographic, behavioral, and health-related factors. Data include 5018 Coronary Artery Risk Development in Young Adults participants (mean (SD) age, 24.8 (3.7) yr; 53.3% female; and 51.4% Black participants) who completed at least one maximal graded exercise test at baseline and/or the year 7 and 20 exams. Maximal and submaximal fitness were estimated by exercise duration and heart rate at the end of stage 2. Multivariable adjusted linear-mixed models were used to estimate fitness trajectories using age as the mechanism for time after adjustment for covariates. Fitness trajectories from ages 20 to 50 yr in 5-yr increments were estimated overall and by subgroups determined by each factor after adjustment for duration within the less favorable category. Mean (95% confidence interval) maximal fitness at age 20 and 50 yr was 613 (607-616) and 357 (350-362) s; submaximal heart rate during this period also reflected age-related fitness declines (126 (125-127) and 138 (137-138) bpm). Compared with men, women had lower maximal fitness at age 20 yr (P < 0.001), which persisted over follow-up (P < 0.001); differences were also found by race within sex strata (all P < 0.001). Differences in maximal fitness at age 20 yr were noted by socioeconomic, behavioral, and health-related status in young adulthood (all P < 0.05), which persisted over follow-up (all P < 0.001) and were generally consistent in sex-stratified analyses. Targeting individuals experiencing accelerated fitness declines with tailored intervention strategies may provide an opportunity to preserve fitness throughout midlife to reduce lifetime cardiovascular disease risk.

Influence of age and gender on cardiovascular response to isometric exercise in apparently healthy individuals

Objective Static exercises are an integral aspect of patient rehabilitation and are employed in advanced strength and endurance training programmes. Exercise is a form of self-induced stress leading to circulatory and respiratory changes, therefore, this study sought to determine the influence of age and gender on the cardiovascular responses of apparently healthy individuals to isometric/static exercises. Methodology Sixty apparently healthy individuals (30 males and 30 females) participated in this study. Their ages ranged between 21–50 years and were grouped into 21–30 years, 31–40 years and 41–50 years. Each participant carried out and maintained 30% of maximal isometric voluntary contraction (MIVC) using hand grip for 1, 2 and 3 minutes respectively, with 30-minutes rest period. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and recorded, at rest, and during each of the sustained contractions. Results There was a statistically significant increase (p &lt;0.05) in the mean SBP, DBP and HR at rest and with every increase in duration (that is, from 1 minute to 3 minutes) of static handgrip contraction, maintained at 30% MIVC in the 3 groups; except for HR for group one (that is, 21–30 years). There was no gender difference (p &gt;0.05) in SBP and DBP of the participants within the 3 groups, although male participants, particularly in group 2 had higher SBP. There was also a statistically significant increase in the HR of female participants compared to the males in group 2. Isometric contraction for 3 minutes produced the greatest change (increase) in cardiovascular parameter across all the groups but more marked among participants in group 2 (that is, 31–40 years). Conclusion The study concluded that submaximal (30% MIVC) isometric upper limb exercise increase blood pressure and heart rate in both sexes, with greatest values when the exercise was sustained for 3 minutes. Hence, efforts should be made to monitor cardiovascular parameters prior to prescribing safe level of isometric exercise. Also, 3 minutes of static/isometric exercises may be avoided, particularly during the rehabilitation of patient with cardiovascular disease.

High-Intensity Interval Training and Sprint-Interval Training in National-Level Rowers.

Purpose: The effects of two different high-intensity training methods on 2,000 m rowing ergometer performance were examined in a feasibility study of 24 national-level rowers aged 18–27 years (17 males, 2,000 m ergometer time trial 6:21.7 ± 0:14.6 (min:s) and seven females, 2,000 m ergometer 7:20.3 ± 0:12.1. Habitual training for all participants was ~12–16 h per week).Methods: 16 high-intensity ergometer sessions were completed across two 3-week periods. Participants were allocated into two groups according to baseline 2,000 m time. High-intensity interval session-sprint-interval session (HIIT-SIT) completed eight HIIT (8 × 2.5 min intervals; 95% of 2,000 m wattage) followed by eight SIT (three sets of 7 × 30 s intervals; maximum effort). SIT-HIIT completed eight SIT sessions followed by eight HIIT sessions. Both a 2,000-m time trial and a progressive incremental test finishing with 4 min “all-out” performance were completed before and after each 3-week phase.Results: Both groups showed similar improvements in 2,000 m time and 4 min “all-out” distance after the first 3 weeks (2,000 m time: HIIT-SIT: −2.0 ± 0.6%, mean ± 90% CL, p = 0.01; SIT-HIIT: −1.5 ± 0.3%, p = 0.01) with no significant difference between groups. HIIT-SIT demonstrated the greatest improvements in submaximal heart rate (HR) during the progressive incremental test with eight sessions of HIIT showing a greater reduction in submaximal HR than eight sessions of SIT. The net improvement of 16 high-intensity sessions on 2,000 m time was −2.5% for HIIT-SIT (−10.6 ± 3.9 s, p = 0.01) and − 2.2% for SIT-HIIT (−9.0 ± 5.7 s, p = 0.01) and for 4 min “all-out” performance was 3.1% for HIIT-SIT (36 ± 25 m, p = 0.01) and 2.8% for SIT-HIIT (33 ± 27 m, p = 0.01).Conclusion: Eight sessions of high-intensity training can improve 2,000 m ergometer rowing performance in national-level rowers, with a further eight sessions producing minimal additional improvement. The method of high-intensity training appears less important than the dose.

Профіль чинників ризику серцево-судинних захворювань при ішемічній хворобі серця в осіб із нормальним і порушеним вуглеводним обміном

Мета дослідження: провести порівняльний аналіз профілю чинників ризику розвитку серцево-судинних захворювань у хворих на ішемічну хворобу серця (ІХС) з нормальним і порушеним вуглеводним обміном. Матеріали і методи. Під спостереженням перебували 142 пацієнти. З метою оцінки частоти різних форм ІХС залежно від стану вуглеводного обміну були сформовані такі групи: перша група — 83 хворі на цукровий діабет (ЦД) 2-го типу, друга група — 34 хворі з порушенням толерантності до глюкози (ПТГ), третя група — 25 пацієнтів із нормальним вуглеводним обміном. Для виявлення ішемічних змін міокарда проводили амбулаторний добовий моніторинг електрокардіограми з обов’язковим досягненням субмаксимальної частоти серцевих скорочень у процесі дослідження. Результати. Безбольова ішемія міокарда була виявлена у 19 (22,9 %) хворих на ЦД 2-го типу, у 3 (8,8 %) осіб із ПТГ і у 2 (8,0 %) пацієнтів із нормальним вуглеводним обміном. Паління, обтяжена спадковість, порушення в системі гемостазу вірогідно частіше траплялися в групі хворих на ЦД 2-го типу з безбольовою ішемією міокарда порівняно з хворими на ЦД 2-го типу без ІХС. Профіль загальнопопуляційних чинників ризику розвитку серцево-судинних захворювань у хворих на ІХС і цукровий діабет 2-го типу належить до найбільш несприятливих. У той же час у пацієнтів із ранніми порушеннями вуглеводного обміну і нормальним вуглеводним обміном він статистично значимо не розрізняється. Висновки. Хворі на ЦД 2-го типу з безбольовою ішемією міокарда порівняно з хворими на ЦД 2-го типу без ІХС мають вірогідно більш виражені порушення показників загальнопопуляційних чинників ризику розвитку серцево-судинних захворювань.

Left atrial conduit flow rate at baseline and during exercise: an index of impaired relaxation in patients with heart failure and preserved ejection fraction

Abstract Introduction In healthy subjects, adrenergic stimulation augments left ventricular (LV) long-axis shortening/lengthening, and increases left atrial (LA) to LV intracavitary pressure gradients in early diastole. Lower increments are observed in patients with heart failure with preserved ejection fraction (HFpEF). Purpose We hypothesized that exercise in HFpEF would similarly impair passive LV filling in early-mid diastole, during conduit flow from pulmonary veins. Methods Twenty HFpEF patients (67.8±9.8 years; 11 women), diagnosed according to 2007 ESC recommendations, underwent ramped semi-supine bicycle exercise to submaximal target heart rate (∼100) or symptoms. Seventeen asymptomatic subjects (64.3±8.9 years; 7 women) served as controls. Simultaneous LA and LV volumes were measured from pyramidal 3D echocardiographic full-volume datasets acquired from apical window at baseline and during stress, together with brachial arterial pressure. LA conduit function was computed, from minimum LV volume to ECG P wave, as [LV volume (time) – LV minimum volume] – [LA maximum volume – LA volume (time)] and expressed as average flow rate. The slope of the single-beat preload recruitable stroke work (PRSW) quantified LV inotropic state. Results There were divergent responses in conduit flow rate, which increased by 40% during exercise in control subjects (+17.8±37.3 ml/s) but decreased by 18% in patients with HFpEF (−9.6±42.3 ml/s) (p=0.046); increments during stress correlated with PRSW slope changes (p=0.003). Conclusion In HFpEF conduit flow rate decreases when diastolic dysfunction develops during exercise, in parallel with LV inotropic state changes, thereby contributing to impaired stroke volume reserve. Conduit flow can be measured as a marker of LV relaxation. Funding Acknowledgement Type of funding sources: None.

Differences in Blood Pressure and Workload Intensity During Arm and Leg Ergometry at Submaximal Target Heart Rates in College-Aged Individuals

Purpose: Blood pressure (BP) during arm (AE) and leg ergometry (LE) have traditionally been compared at submaximal intensities of the peak oxygen uptake, which is often challenging to interpret in clinical practice. The purpose of this investigation was to evaluate the relationship of the heart rate with systolic blood pressure (SBP), diastolic blood pressure (DBP), and workload (WL) during AE and LE exercise. Methods: A prospective, observational, cross-sectional design with 35 healthy subjects compared BP and WL during AE and LE at specific submaximal target heart rates (HRs) of 110, 120, 130, 140, and 150 beats per minute. A linear mixed model tested for differences in SBP, DBP, and WL between AE and LE. Results: There was a larger increase in SBP {0.55 mm Hg (95% CI [0.38, 0.73])} per heart beat during LE. There was a larger increase in WL {0.62 watts (95% CI [0.38, 0.85])} and WL relative to body mass {0.01 watts/kg (95% CI [0.006, 0.011])} per heart beat during LE. Statistical models were developed that estimated SBP, DBP, and WL based on the submaximal heart rate. Conclusion: The findings from this investigation informs physical therapists that lower SBP, higher DBP, and lower WL is achieved at any given submaximal HR during AE compared with LE. Furthermore, prediction equations derived from the statistical models can be used to compare actual against predicted SBP and DBP responses to determine tolerance to exercise. Finally, differences in WL per beat increase in HR are valuable in dosing exercise on the AE or LE.

Left atrial conduit flow rate at baseline and during exercise: an index of impaired relaxation in HFpEF patients.

AimsIn healthy subjects, adrenergic stimulation augments left ventricular (LV) long‐axis shortening and lengthening, and increases left atrial (LA) to LV intracavitary pressure gradients in early diastole. Lower increments are observed in patients with heart failure with preserved ejection fraction (HFpEF). We hypothesized that exercise in HFpEF would further impair passive LV filling in early‐mid diastole, during conduit flow from pulmonary veins.Methods and resultsTwenty HFpEF patients (67.8 ± 9.8 years; 11 women), diagnosed using 2007 ESC recommendations, underwent ramped semi‐supine bicycle exercise to submaximal target heart rate (∼100 bpm) or symptoms. Seventeen asymptomatic subjects (64.3 ± 8.9 years; 7 women) were controls. Simultaneous LA and LV volumes were measured from pyramidal 3D‐echocardiographic full‐volume datasets acquired from an apical window at baseline and during stress, together with brachial arterial pressure. LA conduit flow was computed from the increase in LV volume from its minimum at end‐systole to the last frame before atrial contraction (onset of the P wave), minus the reduction in LA volume during the same time interval; the difference was integrated and expressed as average flow rate, according to a published formula. The slope of single‐beat preload recruitable stroke work (PRSW) quantified LV inotropic state. 3D LV torsion (rotation of the apex minus rotation of the base divided by LV length) was also measurable, both at rest and during stress, in 10 HFpEF patients and 4 controls. There were divergent responses in conduit flow rate, which increased by 40% during exercise in controls (+17.8 ± 37.3 mL/s) but decreased by 18% in patients with HFpEF (−9.6 ± 42.3 mL/s) (P = 0.046), along with congruent changes (+1.77 ± 1.13°/cm vs. −1.94 ± 2.73°/cm) in apical torsion (P = 0.032). Increments of conduit flow rate and apical torsion during stress correlated with changes in PRSW slope (P = 0.003 and P = 0.006, respectively).ConclusionsIn HFpEF, conduit flow rate decreases when diastolic dysfunction develops during exercise, in parallel with changes in LV inotropic state and torsion, contributing to impaired stroke volume reserve. Conduit flow is measurable using 3D‐echocardiographic full‐volume atrio‐ventricular datasets, and as a marker of LV relaxation can contribute to the diagnosis of HFpEF.

Dynamics of coronary artery velocity flow during exercise echocardiography

Purpose The aim of our study was to acquire non-invasive data from coronary flow velocity profiles during exercise in groups of healthy subjects and of patients with arterial hypertension. Material and Methods We enrolled 83 patients into two groups: (1) 35 non-selected consecutive healthy subjects; (2) 25 consecutive patients with arterial hypertension. All the patients performed supine bicycle symptoms-limited tests. Throughout exercise the diastolic peaks of coronary flow velocity in LAD were recorded. Coronary flow velocity reserve (CFVR) was calculated off-line. Profiles of coronary artery velocity were acquired for all groups. The coronary artery flow parameters investigated were comparable in healthy and hypertensive patients at every stage. Results The average diastolic velocities were 54.8 ± 12.9 vs. 51.8 ± 12.2 cm/s, at 50 W; 69.2 ± 17.1 vs 64.4 ± 19.1 cm/s at 75 W; 70.7 ± 16.4 vs. 76.1 ± 19.0 cm/s at 100 W; 80.0 ± 16.0 vs. 72.9 ± 16.1 cm/s at 125 W; 83.7 ± 12.2 vs. 81.4 ± 17.0 at 150 W, p- non-significant, respectively. On average, the healthy group reached CFVR > 2.0 at a heart rate of 110–120 beats/min at 75 W. During supine bicycle exercise, healthy subjects and patients with arterial hypertension have a similar coronary artery flow velocity profile. Conclusion The routine exercise echocardiography test can feasibly be supplemented with the additional measurement of coronary flow velocity during routine supine exercise stress tests, as the normal range of CFVR is reached before submaximal heart rate.

Pattern of the Heart Rate Performance Curve in Subjects with Beta-Blocker Treatment and Healthy Controls.

(1): Heart rate performance curve (HRPC) in incremental exercise was shown to be not uniform, causing false intensity estimation applying percentages of maximal heart rate (HRmax). HRPC variations are mediated by β-adrenergic receptor sensitivity. The aim was to study age and sex dependent differences in HRPC patterns in adults with β-blocker treatment (BB) and healthy controls (C). (2): A total of 535 (102 female) BB individuals were matched 1:1 for age and sex (male 59 ± 11 yrs, female 61 ± 11 yrs) in C. From the maximum incremental cycle ergometer exercise a first and second heart rate (HR) threshold (Th1 and Th2) was determined. Based on the degree of the deflection (kHR), HRPCs were categorized as regular (downward deflection (kHR > 0.1)) and non-regular (upward deflection (kHR < 0.1), linear time course). (3): Logistic regression analysis revealed a higher odds ratio to present a non-regular curve in BB compared to C (females showed three times higher odds). The odds for non-regular HRPC in BB versus C decreased with older age (OR interaction = 0.97, CI = 0.94–0.99). Maximal and submaximal performance and HR variables were significantly lower in BB (p < 0.05). %HRmax was significantly lower in BB versus C at Th2 (male: 77.2 ± 7.3% vs. 80.8 ± 5.0%; female: 79.2 ± 5.1% vs. 84.0 ± 4.3%). %Pmax at Th2 was similar in BB and C. (4): The HRPC pattern in incremental cycle ergometer exercise is different in individuals receiving β-blocker treatment compared to healthy individuals. The effects were also dependent on age and sex. Relative HR values at Th2 varied substantially depending on treatment. Thus, the percentage of Pmax seems to be a stable and independent indicator for exercise intensity prescription.

The Efficacy of Heat Acclimatization Pre-World Cup in Female Soccer Players.

The efficacy of a 14-day field-based heat acclimatization (HA) training camp in 16 international female soccer players was investigated over three phases: phase 1: 8 days moderate HA (22. 1°C); phase 2: 6 days high HA (34.5°C); and phase 3: 11 days of post-HA (18.2°C), with heart rate (HR), training load, core temp (Tc), and perceptual ratings recorded throughout. The changes from baseline (day−16) in (i) plasma volume (PV), (ii) HR during a submaximal running test (HRex) and HR recovery (HRR), and (iii) pre-to-post phase 2 (days 8–13) in a 4v4 small-sided soccer game (4V4SSG) performance were assessed. Due to high variability, PV non-significantly increased by 7.4% ± 3.6% [standardized effect (SE) = 0.63; p = 0.130] from the start of phase 1 to the end of phase 2. Resting Tc dropped significantly [p < 0.001 by −0.47 ± 0.29°C (SE = −2.45)], from day 1 to day 14. Submaximal running HRR increased over phase 2 (HRR; SE = 0.53) after having decreased significantly from baseline (p = 0.03). While not significant (p > 0.05), the greatest HR improvements from baseline were delayed, occurring 11 days into phase 3 (HRex, SE = −0.42; HRR, SE = 0.37). The 4v4SSG revealed a moderate reduction in HRex (SE = −0.32; p = 0.007) and a large increase in HRR (SE = 1.27; p < 0.001) from pre-to-post phase 2. Field-based HA can induce physiological changes beneficial to soccer performance in temperate and hot conditions in elite females, and the submaximal running test appears to show HRex responses induced by HA up to 2 weeks following heat exposure.

Using Submaximal Exercise Heart Rate for Monitoring Cardiorespiratory Fitness Changes in Professional Soccer Players: A Replication Study.

To assess the value of monitoring changes in fitness in professional soccer players, using changes in heart rate at submaximal intensity (HR12km/h) over the velocity at a lactate concentration of 4mmol/L (v4mmol/L). The authors reexamined (1)a range of threshold magnitudes, which may improve detecting substantial individual changes and (2)the agreement between changes in these 2 variables. On at least 2 occasions during different moments of the season, 97 professional soccer players from Germany (first, second, and fourth division) completed an incremental test to determine HR12km/h and v4mmol/L. Optimal thresholds for changes in HR12km/h and v4mmol/L were assessed, using various methods (eg,smallest worthwhile change + typical error [TE], successive reiterations approach). Agreement between both variable changes was examined for the whole sample (225 comparisons), 4 different subgroups (depending on the moment of the season), and in an individual over 6 years (n = 23 tests). Changes of 4.5% and 6.0% for HR12km/h and v4mmol/L, respectively, were rated as optimal to indicate substantial changes in fitness. Depending on the (sub)groups analyzed, these thresholds yielded 0% to 2% full mismatches, 22% to 38% partial agreements, and 60% to 78% full agreements in terms of fitness change interpretation between both variables. When lactate sampling during incremental tests is not possible, practitioners willing to monitor adult professional soccer players' (Germany; first, second, and fourth division) training status can confidently implement short, 3-minute submaximal runs, with 4.5% changes in HR12km/h being indicative of true substantial fitness changes, with 60% to 78% accuracy. Future studies should investigate the potential role of confounding factors of HR12km/h to improve changes in fitness prediction.

The Influence of Age on Cardiovascular, Motor, and Lifestyle Components in Hispanic-Latinos Living with HIV

Background: People living with HIV experience various comorbidities associated with aging. As this population grows older, these comorbidities cause physical impairments that decrease functional autonomy and quality of life. Purpose: This investigation aims to characterize various components affecting Hispanic Latino people living with HIV (PLHIV) concerning age. Methods: Data was extracted from 323 participants’ records enrolled in La Perla de Gran Precio’s HIV Community Center in Puerto Rico. Participants were allocated into the following age groups for comparison: 40 years or less (L-HIV group) and above 40 years of age (U-HIV group). Multiple one-way ANOVAs were applied to compare the data between the two age groups based on five components: cardio, motor, lipid panel, comorbidities, and lifestyle. Results: There were 44 participants allocated to the L-HIV group (age =35.4+/-3.7) and 279 to the U-HIV group (age=56.3+/-7.4). The cardio components (time completed on the submaximal treadmill test and peak heart rate) were significantly less in the upper age group. The U-HIV group also demonstrated substantially slower gait speed and less inclination achieved on the submaximal treadmill test. Lastly, the U-HIV group consisted of more participants with multiple comorbidities. Conclusion: In Hispanic Latino PLHIV, more significant cardiovascular and motor deficits were identified in the U-HIV group in addition to an increased rate of multi-morbidity. Future inquiries are desired to resolve if the time since diagnosis is an acceptable indicator of cardio-motor deterioration and an upsurge in multiple comorbidities experienced in this population.

Individualized Aerobic Exercise in Neuromuscular Diseases: A Pilot Study on the Feasibility and Preliminary Effectiveness to Improve Physical Fitness.

ObjectiveClear guidelines to prescribe aerobic exercise in neuromuscular diseases (NMD) are lacking, which hampers effective application in neuromuscular rehabilitation. This pilot study evaluated the feasibility and preliminary effectiveness of an individualized aerobic exercise program according to a recently developed training guide (B-FIT) to improve physical fitness in individuals with NMD.MethodsThirty-one individuals who were ambulatory and had 15 different slowly progressive NMD participated in a 4-month, polarized, home-based, aerobic exercise program. The program included 2 low-intensity sessions and 1 high-intensity session per week. Feasibility outcomes were the following: completion rate, proportion of followed sessions, adverse events, and participant and therapist satisfaction based on a self-designed questionnaire. Submaximal incremental exercise tests were used to assess the effects on physical fitness.ResultsTwenty-six participants (84%) completed the B-FIT program, and the proportion of followed sessions was >75%. Three adverse events were reported and resolved. Regarding satisfaction, participants (based on n = 9) reported feeling fitter, but training was considered insufficiently challenging. Physical therapists (n = 5) reported that B-FIT provides a clear, well-grounded guidance. They perceived the time investment for initiating the program and the carry-over to primary care as the main barriers. The mean (SD) submaximal heart rate (based on n = 20) reduced significantly by −6.5 beats per minute (95% CI = −11.8 to −1.2), from 121.7 (16.5) at baseline to 115.2 (14.3) after intervention. Submaximal ratings of perceived exertion, anaerobic threshold, and peak workload also improved significantly (P < .05).ConclusionThe outcomes of this pilot study suggest that individualized aerobic exercise according to B-FIT is feasible and has potential to improve physical fitness in a wide variety of slowly progressive NMD. However, some barriers must be addressed before investigating the efficacy in a randomized controlled trial.ImpactThe outcomes of this study demonstrate the feasibility of individualized aerobic exercise according to the B-FIT training guide and the potential to improve physical fitness in NMD. Physical therapists indicated that the use of B-FIT provides a clear, well-grounded guidance. The training guide can support health care professionals in the application of aerobic exercise in adult neuromuscular rehabilitation.Lay SummaryIndividualized exercise according to the B-FIT training guide is feasible in a wide variety of slowly progressive NMD and might help improve physical fitness.

High-intensity downhill running exacerbates heart rate and muscular fatigue in trail runners

ABSTRACT This study explores the cardiorespiratory and muscular fatigue responses to downhill (DR) vs uphill running (UR) at similar running speed or similar oxygen uptake (⩒O2). Eight well-trained, male, trail runners completed a maximal level incremental test and three 15-min treadmill running trials at ±15% slope: i) DR at ~6 km·h−1 and ~19% ⩒O2max (LDR); ii) UR at ~6 km·h−1 and ~70% ⩒O2max (HUR); iii) DR at ~19 km·h−1 and ~70% ⩒O2max (HDR). Cardiorespiratory responses and spatiotemporal gait parameters were measured continuously. Maximal isometric torque was assessed before and after each trial for hip and knee extensors and plantar flexor muscles. At similar speed (~6 km·h−1), cardiorespiratory responses were attenuated in LDR vs HUR with altered running kinematics (all p < 0.05). At similar ⩒O2 (~3 l·min−1), heart rate, pulmonary ventilation and breathing frequency were exacerbated in HDR vs HUR (p < 0.01), with reduced torque in knee (−15%) and hip (−11%) extensors and altered spatiotemporal gait parameters (all p < 0.01). Despite submaximal metabolic intensity (70% ⩒O2max), heart rate and respiratory frequency reached maximal values in HDR. These results further our understanding of the particular cardiorespiratory and muscular fatigue responses to DR and provide the bases for future DR training programs for trail runners.

Obese Patients Decrease Work Rate in Order to Keep a Constant Target Heart Rate.

"Slow components" of heart rate (HR) kinetics, occurring also during moderate-intensity constant work rate exercise, represent a problem for exercise prescription at fixed HR values. This problem, described in young healthy subjects, could be more pronounced in obese patients. Sixteen male obese patients (age, 22 ± 7 yr; body mass, 127 ± 19 kg; body mass index, 41.6 ± 3.9 kg·m-2) were tested before (PRE) and after (POST) a 3-wk multidisciplinary body mass reduction program, entailing moderate-intensity exercise. They performed on a cycle ergometer an incremental exercise to voluntary exhaustion (to determine peak pulmonary oxygen uptake (V˙O2peak) and gas exchange threshold (GET)) and constant work rate exercises: moderate-intensity (MODERATE; 80% of GET determined in PRE), heavy-intensity (HEAVY; 120% of GET determined in PRE), and "HRCLAMPED" exercise, in which work rate was continuously adjusted to maintain a constant HR corresponding to that at 120% of GET. Breath-by-breath V˙O2 and HR were determined. V˙O2peak and GET (expressed as a percent of V˙O2peak) were not significantly different in PRE versus POST. In POST versus PRE, the HR slow component disappeared (MODERATE) or was reduced (HEAVY). In PRE, work rate had to decrease by ~20% over a 15-min task in order to keep HR constant; this decrease was significantly smaller (~5%) in POST. In obese patients, a 3-wk multidisciplinary body mass reduction intervention i) increased exercise tolerance by eliminating (during MODERATE) or by reducing (during HEAVY) the slow component of HR kinetics, and ii) facilitated exercise prescription by allowing to translate a fixed submaximal HR value into a work rate slightly above GET.

Effectiveness of caffeine intake on maximal and sub-maximal physiological markers of exercise intensity among wheelchair users compared to able-bodied individuals

The aim of the current study was to assess the effect of caffeine intake on maximal and sub-maximal physiological markers of exercise intensity and whether group (able-bodied and wheelchair users) moderated these findings. Ten able-bodied men (20.3±2.4 years, length 174.3±5.1 cm, 76.4±9.4 kg) and 9 wheelchair users (29.9±7.1 years, length 164±13 cm, 78.6±20.6 kg) participated in the study. Each participant performed 4 exercise tests. Two ramp exercise tests were used to assess the effect of caffeine intake on maximal values of power output (PO), oxygen uptake (VO2), heart rate (HR), lactate and rate of perceived exertion (RPE): one performed with 6 mg/kg body mass of caffeine ingestion as gelatine capsules, and the second one with placebo. Two constant-load exercise tests at 70% POpeak to volitional exhaustion were used to assess the effect caffeine intake on sub-maximal values of VO2, HR, lactate and RPE: one performed with 6 mg/kg body mass of caffeine ingestion as gelatine capsules, and the second one with placebo. Two way ANOVA revealed that caffeine intake does not affect maximal values of VO2, HR, lactate and RPE (P&gt;0.05). Caffeine intake reduced sub-maximal RPE at 5 min (P&lt;0.05) and 10 min of exercise. Sub-maximal HR at 70% POpeak was higher in caffeine than placebo among wheelchair users (P&lt;0.05). Time to exhaustion at 70% POpeak was significantly longer in caffeine than placebo (P&lt;0.05). VO2max and POpeak were significantly higher among able-bodied than wheelchair users (P&lt;0.05). Caffeine has an effect on sub-maximal RPE and time to volitional exhaustion. Closed-loop exercise mode should be employed in future studies. Greater dosage of caffeine could be used but should not exceed the permitted amount of 12 mg/kg body mass. Wheelchair users should exercise and do more physical activity to enhance VO2max and POpeak.