Effects of Plyometric Training Volume on Physical Performance in Youth Basketball Players.

ABSTRACT: Aztarain-Cardiel, K, Garatachea, N, and Pareja-Blanco, F. Effects of plyometric training volume on physical performance in youth basketball players. J Strength Cond Res 38(7): 1275-1279, 2024-The aim of this study was to analyze the effects of different plyometric training volumes on jumping, sprinting, and change-of-direction performances in youth basketball players. Thirty-one young male basketball players (age: 15.1 ± 1.8 years) from 4 squads belonging to an elite basketball club were randomly assigned to 1 of 3 groups: (a) low-volume (LV) plyometric training, (b) high-volume (HV) plyometric training, and (c) control group (CG). The subjects followed a plyometric training program twice a week for 6 weeks, differing in the training volume controlled through the number of jumps per session. Both experimental groups performed 8 repetitions in each set of bilateral vertical jumps with free arms, but HV completed twice the training volume of LV (98.7 vs. 49.3 jumps per session). Pretraining and Posttraining measurements included the following: (a) squat jump (SJ); (b) countermovement jump (CMJ); (c) horizontal jump (HJ); (d) straight-line sprint in 20 m (Sprint); and (e) V-Cut change-of-direction test (V-Cut). The LV and HV groups showed similar increases in vertical jump performance. The LV group significantly increased its performance in SJ, CMJ, and HJ (p < 0.001-0.05), whereas the HV group showed significant improvements only in SJ and CMJ (p < 0.001). Furthermore, neither group increased their sprint or change of direction performance. Control group did not improve in any performance variable analyzed. Therefore, the LV and HV plyometric training programs produce similar benefits on jump performance variables, but LV is more repetition-efficient than HV in young basketball players. This supports the statement that there is a nonlinear relationship between training volume and performance improvements.

Effects of Plyometric Training Direction on Physical Performance in Basketball Players.

PURPOSE: The aim of this study was to analyze the effects of plyometric training direction on jumping, sprinting, and change-of-direction ability in basketball players. METHODS: Forty male basketball players (21.8 [3.8] y), from 4 teams that competed in regional and national championships, were randomly assigned to 1 of 4 groups: (1) vertical jump group, (2) horizontal jump group, (3) vertical and horizontal jump group, and (4) control group. The subjects followed a plyometric training program twice a week for 6 weeks, differing in the execution direction of the jumps. All groups performed the same total training volume of acyclic and cyclic jumps controlled through the number of contacts per session. Pretraining and posttraining measurements included (1) rocket jump, (2) Abalakov jump, (3) horizontal jump, (4) 20-m linear sprint, and (5) V-Cut change-of-direction test. RESULTS: The vertical and horizontal jump group showed significant increases in all performance variables examined, except for linear sprint performance, in which no group improved. The vertical jump group showed significant improvements in rocket jump and Abalakov jump (P < .01), but worsened significantly in terms of sprint performance (P < .05). The horizontal jump group showed significant increases in rocket jump and horizontal jump (P < .001-.01). Furthermore, all experimental groups showed improved V-Cut change-of-direction test performance. CONCLUSIONS: These results indicate that combining vertical and horizontal jumps induces improvements in more capabilities than does training only vertical or horizontal jumps with the same training volume. Training only vertical or horizontal jumps will improve performance mainly in vertically or horizontally oriented tasks, respectively.

Physical Activity in Centenarians beyond Cut-Point-Based Accelerometer Metrics.

This study described and compared physical activity (PA) characteristics at the end of the human lifespan using conventional cut-point-based versus cut-point-free accelerometer metrics. Eighteen institutionalized centenarians (101.5 ± 2.1 years, 72.2% female, 89% frail) wore the wrist GENEActiv accelerometer for 7 days. Conventional metrics, such as time spent in light-intensity PA (LiPA) and moderate-to-vigorous intensity PA (MVPA) were calculated according to published cut-points for adults and older adults. The following cut-point-free metrics were evaluated: average acceleration, intensity gradient and Mx metrics. Depending on the cut-point, centenarians accumulated a median of 15-132 min/day of LiPA and 3-15 min/day of MVPA. The average acceleration was 9.2 mg [Q1: 6.7 mg-Q3: 12.6 mg] and the intensity gradient was -3.19 [-3.34--3.12]. The distribution of Z-values revealed positive skew for MVPA, indicating a potential floor effect, whereas the skew magnitude was attenuated for cut-point-free metrics such as intensity gradient or M5. However, both cut-point-based and cut-point-free metrics were similarly positively associated with functional independence, cognitive and physical capacities. This is the first time that PA has been described in centenarians using cut-point-free metrics. Our results suggest that new analytical approaches could overcome cut-point limitations when studying the oldest-old. Future studies using these new cut-point-free PA metrics are warranted to provide more complete and comparable information across groups and populations.

Acute effects of long-distance races on heart rate variability and arterial stiffness: A systematic review and meta-analysis.

This study systematically reviewed and quantified the effects of running a long-distance race (LDR) on heart rate variability (HRV) and arterial stiffness (AS). All types of races of a distance equal to or greater than a marathon (≥42.2 km) were included. A total of 2,220 articles were identified, 52 were included in the qualitative analysis, and 48 were meta-analysed. The standardised mean difference pre- and post-race of various time-domain and frequency-domain indices of HRV, mean arterial blood pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP) and carotid-femoral pulse wave velocity (cfPWV) was calculated. Regarding HRV, there was a significant decrease in most of the variables considered as markers of parasympathetic activity, indicating a shift of autonomic balance towards a reduced vagal tone. Regarding vascular variables, there was a significant drop in blood pressure and reduced AS. In conclusion, running an LDR seems to have a considerable acute effect on the autonomic nervous system, haemodynamics, and vascular properties. The observed effects could be categorised within the expected acute responses to long-lasting, strenuous exercise.

ECG Ventricular Repolarization Dynamics during Exercise: Temporal Profile, Relation to Heart Rate Variability and Effects of Age and Physical Health.

Periodic repolarization dynamics (PRD) is a novel electrocardiographic marker of cardiac repolarization instability with powerful risk stratification capacity for total mortality and sudden cardiac death. Here, we use a time-frequency analysis approach to continuously quantify PRD at rest and during exercise, assess its dependence on heart rate variability (HRV) and characterize the effects of age (young adults/middle-aged adults/older adults), body mass index (non-overweight/overweight) and cardiorespiratory fitness level (fit/unfit). Sixty-six male volunteers performed an exercise test. RR and dT variabilities (RRV, dTV), as well as the fraction of dT variability unrelated to RR variability, were computed based on time-frequency representations. The instantaneous LF power of dT (PdTV), representing the same concept as PRD, and of its RRV-unrelated component (PdTVuRRV) were quantified. dT angle was found to mostly oscillate in the LF band. Overall, 50-70% of PdTV was linearly unrelated to RRV. The onset of exercise caused a sudden increase in PdTV and PdTVuRRV, which returned to pre-exercise levels during recovery. Clustering analysis identified a group of overweight and unfit individuals with significantly higher PdTV and PdTVuRRV values at rest than the rest of the population. Our findings shed new light on the temporal profile of PRD during exercise, its relationship to HRV and the differences in PRD between subjects according to phenotypic characteristics.

Validity of the Polar H7 Heart Rate Sensor for Heart Rate Variability Analysis during Exercise in Different Age, Body Composition and Fitness Level Groups.

This work aims to validate the Polar H7 heart rate (HR) sensor for heart rate variability (HRV) analysis at rest and during various exercise intensities in a cohort of male volunteers with different age, body composition and fitness level. Cluster analysis was carried out to evaluate how these phenotypic characteristics influenced HR and HRV measurements. For this purpose, sixty-seven volunteers performed a test consisting of the following consecutive segments: sitting rest, three submaximal exercise intensities in cycle-ergometer and sitting recovery. The agreement between HRV indices derived from Polar H7 and a simultaneous electrocardiogram (ECG) was assessed using concordance correlation coefficient (CCC). The percentage of subjects not reaching excellent agreement (CCC > 0.90) was higher for high-frequency power (PHF) than for low-frequency power (PLF) of HRV and increased with exercise intensity. A cluster of unfit and not young volunteers with high trunk fat percentage showed the highest error in HRV indices. This study indicates that Polar H7 and ECG were interchangeable at rest. During exercise, HR and PLF showed excellent agreement between devices. However, during the highest exercise intensity, CCC for PHF was lower than 0.90 in as many as 60% of the volunteers. During recovery, HR but not HRV measurements were accurate. As a conclusion, phenotypic differences between subjects can represent one of the causes for disagreement between HR sensors and ECG devices, which should be considered specifically when using Polar H7 and, generally, in the validation of any HR sensor for HRV analysis.

Estimation of the second ventilatory threshold through ventricular repolarization profile analysis.

Under the hypothesis that sympathetic control of ventricular repolarization may change once the second ventilatory threshold (VT2) has been reached, a novel methodology for non-invasive VT2 estimation based on the analysis of the T wave from the electrocardiogram (ECG) is proposed, and potential underlying physiological mechanisms are suggested. 25 volunteers (33.4 ± 5.2 years) underwent an incremental power cycle ergometer test (25 W/minute). During the test, respiratory gas exchange and multi-lead ECG were acquired. The former was employed to determine VT2, used here as a reference, whereas the latter was used to compute the temporal profiles of an index of ventricular repolarization instability (dT) and its low-frequency (LF) oscillations (LFdT). The sudden increases observed in dT and LFdT profiles above an established heart rate threshold were employed to derive VT2 estimates, referred to as VT2d T and VT2LF d T , respectively. Estimation errors of -4.7 ± 25.2 W were obtained when considering VT2d T . Errors were lower than the one-minute power increment of 25 W in 68% of the subjects and lower than 50 W in 89.5% of them. When using VT2LF d T , estimation error was of 15.3 ± 32.4 W. Most of the subjects shared common characteristic dT and LFdT profiles, which could be reflecting changes in the autonomic control of ventricular repolarization before and after reaching VT2. The analysis of ventricular repolarization dynamics during exercise allows non-invasive ECG-based estimation of VT2, possibly in relation to changes in the autonomic control of ventricular electrical activity when VT2 is reached.

Heart Rate Variability and Exceptional Longevity.

Centenarians are the paradigm of human extreme longevity and healthy aging, because they have postponed, if not avoided, mayor age-related diseases. The purpose of this study was to investigate potential differences in resting heart rate variability (HRV) between young adults, octogenarians, and centenarians and assess whether HRV variables are predictors of all-cause mortality in centenarians. To this end, three groups of participants: young adults (N = 20; 20.6 ± 2.3 years), octogenarians (N = 18; 84.1 ± 2.6 years), and centenarians (N = 17; 101.9 ± 1.9 years) were monitored for 15 min at rest (seated, without moving or talking) to measure RR intervals, from which HRV was evaluated. Our results showed a clear decrease with age in the main parasympathetic HRV variables, as well as in the standard deviation (SD) of the RR series [SD of normal-to-normal interval (SDNN)] and in low frequency (LF) heart rate (HR) oscillations, although differences between octogenarians and centenarians did not reach statistical significance. In 14 centenarians followed until death, only SDNN showed significant correlation (ρ = 0.536; p = 0.048) with survival prognosis. Additionally, SDNN <19 ms was associated with early mortality (≤1 year) in centenarians (Hazard Ratio = 5.72). In conclusion, HRV indices reflecting parasympathetic outflow as well as SDNN and LF all present an age-related reduction, which could be representative of a natural exhaustion of allostatic systems related to age. Moreover, low SDNN values (<19 ms) could be associated with early mortality in centenarians. HRV seems to play a role in exceptional longevity, which could be accounted for by centenarians' exposome.

Effects of a 75-km mountain ultra-marathon on heart rate variability in amateur runners.

BACKGROUND: This study examined the effects of a mountain ultra-marathon (MUM) on the activity of the autonomous nervous system through heart rate variability (HRV) monitoring and determined whether this variable related to final performance. METHODS: Heart rate and HRV were measured in eight male amateur runners (aged 37-60 years). Measurements were recorded before and after the event, in resting conditions, as well as continuously throughout the whole MUM. In addition, percentage (%) of heart rate reserve (HRres) and partial and total times during the race were analyzed. RESULTS: Average heart rate (HRavg) measured at rest was increased after the event (+37%). Standard deviation of successive differences (SDSD) and the square root of the mean squared differences of successive NN intervals (RMSSD) were reduced after the MUM (-56% and -59%, respectively). There was a positive relationship between the frequency-domain index normalized low frequency power (PLFn) measured at rest before the event and race time (0.79) while there was a negative relationship between race time and the difference in HRavg before and after the event. In the last half of the event, there was a high correlation (Spearman coefficient of correlation >0.9) between race time and the standard deviation of the NN intervals (SDNN) registered during the race. CONCLUSIONS: Autonomous cardiac regulation can be related to the performance in a mountain ultra-marathon. HRV monitoring could represent a practical tool for the evaluation of the relationship between the autonomous nervous system activity and performance in a mountain ultra-marathon.

Electrocardiogram-Derived Tidal Volume During Treadmill Stress Test.

OBJECTIVE: Electrocardiogram (ECG) has been regarded as a source of respiratory information with the main focus in the estimation of the respiratory rate. Although little research concerning the estimation of tidal volume (TV) has been conducted, there are several ECG-derived features that have been related with TV in the literature, such as ECG-derived respiration, heart rate variability, and respiratory rate. In this paper, we exploited these features for estimating TV using a linear model. METHODS: 25 young (33.4 ± 5.2 years) healthy male volunteers were recruited for performing a maximal (MaxT) and a submaximal (SubT) treadmill stress test, which were conducted on different days. Both tests were automatically segmented in stages attending to the heart rate. Afterwards, a subject-specific TV model was calibrated for each stage, employing features from MaxT, and the model was later used for estimating the TV in SubT. RESULTS: During exercise, the different proposed approaches led to relative fitting errors lower than 14% in most of the cases and 6% in some of them. CONCLUSION: Low achieved fitting errors suggest that TV can be estimated from ECG during a treadmill stress test. SIGNIFICANCE: The results suggest that it is possible to estimate TV during exercise using only ECG-derived features.

Healthspan and lifespan extension by fecal microbiota transplantation into progeroid mice.

The gut microbiome is emerging as a key regulator of several metabolic, immune and neuroendocrine pathways1,2. Gut microbiome deregulation has been implicated in major conditions such as obesity, type 2 diabetes, cardiovascular disease, non-alcoholic fatty acid liver disease and cancer3-6, but its precise role in aging remains to be elucidated. Here, we find that two different mouse models of progeria are characterized by intestinal dysbiosis with alterations that include an increase in the abundance of Proteobacteria and Cyanobacteria, and a decrease in the abundance of Verrucomicrobia. Consistent with these findings, we found that human progeria patients also display intestinal dysbiosis and that long-lived humans (that is, centenarians) exhibit a substantial increase in Verrucomicrobia and a reduction in Proteobacteria. Fecal microbiota transplantation from wild-type mice enhanced healthspan and lifespan in both progeroid mouse models, and transplantation with the verrucomicrobia Akkermansia muciniphila was sufficient to exert beneficial effects. Moreover, metabolomic analysis of ileal content points to the restoration of secondary bile acids as a possible mechanism for the beneficial effects of reestablishing a healthy microbiome. Our results demonstrate that correction of the accelerated aging-associated intestinal dysbiosis is beneficial, suggesting the existence of a link between aging and the gut microbiota that provides a rationale for microbiome-based interventions against age-related diseases.

Physical Activity and Sedentary Behavior at the End of the Human Lifespan.

To objectively assess physical activity levels and sedentary behavior in a cohort of Spanish centenarians and their nonagenarian peers. Physical activity and sedentary behavior patterns were objectively measured by an ActiGraph GT3X accelerometer in centenarians (n = 18; 83% women; 100.8 ± 0.8 [100-103] years) and nonagenarians (n = 11; 91% women; 93.3 ± 2.5 [90-98] years). Centenarians showed less counts per minute (17.6 ± 7.1 vs. 46.1 ± 23.7, p = .003, d = 1.851) and steps per day (455 ± 237 vs. 1,249 ± 776, p = .007, d = 1.587) than nonagenarians. The daily number of sedentary breaks was also lower in the former (5.0 ± 1.5 vs. 6.7 ± 2.0, p = .019, d = 0.971). When observing time distribution, the most active day period in both groups was the morning, with a peak between 10:00 and 11:59. This data suggest that the decline in physical activity levels continues to worsen until the end of the human lifespan.

Effects of Whole Body Vibration on Tibia Strength and Structure of Competitive Adolescent Swimmers: A Randomized Controlled Trial.

BACKGROUND: Swimming has no effect on bone mass or structure. Therefore, adolescent swimmers present similar bone strength values when compared to normo-active controls, and lower values when compared to weight-bearing athletes. It thus seems necessary to try to improve bone structure and strength of adolescent swimmers through a weight-bearing intervention in order to reduce the risk of suffering osteoporosis later in life. OBJECTIVE: To evaluate the effects of a 6-month whole body vibration (WBV) intervention on bone strength and structure of adolescent swimmers. DESIGN: Randomized controlled trial. SETTING: Research center. PARTICIPANTS: A total of 51 swimmers (14.4 ± 2.0 years) participated in the study. METHODS: Swimmers were randomly allocated into 2 groups: 20 swimmers (9 females) who only performed their swimming training, and 31 swimmers (15 females) who performed their swimming training and received a WBV intervention (3.6-11.6 g) 3 times per week during 6 months (VIB). OUTCOME MEASUREMENTS: Peripheral quantitative computed tomography was performed in the nondominant tibia of all swimmers at 4%, 38%, and 66% of the tibia length before and after the intervention. RESULTS: No differences between groups in any bone structure variable were found at pre- or postintervention. Both groups presented similar improvements in time, and no group by time interactions were found, suggesting that the WBV intervention was not intense enough to achieve positive changes in bone strength or structure. CONCLUSION: WBV, at the chosen intensities and durations, had no effect on adolescent swimmers' bone strength or structure. Future studies should test other weight-bearing interventions aiming to improve bone strength and structure of adolescent swimmers. LEVEL OF EVIDENCE: II.

Methodological framework for heart rate variability analysis during exercise: application to running and cycling stress testing.

Standard methodologies of heart rate variability analysis and physiological interpretation as a marker of autonomic nervous system condition have been largely published at rest, but not so much during exercise. A methodological framework for heart rate variability (HRV) analysis during exercise is proposed, which deals with the non-stationary nature of HRV during exercise, includes respiratory information, and identifies and corrects spectral components related to cardiolocomotor coupling (CC). This is applied to 23 male subjects who underwent different tests: maximal and submaximal, running and cycling; where the ECG, respiratory frequency and oxygen consumption were simultaneously recorded. High-frequency (HF) power results largely modified from estimations with the standard fixed band to those obtained with the proposed methodology. For medium and high levels of exercise and recovery, HF power results in a 20 to 40% increase. When cycling, HF power increases around 40% with respect to running, while CC power is around 20% stronger in running.

Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

Is the SenseWear Armband accurate enough to quantify and estimate energy expenditure in healthy adults?

BACKGROUND: The SenseWear Armband (SWA) is a monitor that can be used to estimate energy expenditure (EE); however, it has not been validated in healthy adults. The objective of this paper was to study the validity of the SWA for quantifying EE levels. METHODS: Twenty-three healthy adults (age 40-55 years, mean: 48±3.42 years) performed different types of standardized physical activity (PA) for 10 minutes (rest, walking at 3 and 5 km·h-1, running at 7 and 9 km·h-1, and sitting/standing at a rate of 30 cycle·min-1). Participants wore the SWA on their right arm, and their EE was measured by indirect calorimetry (IC) the gold standard. RESULTS: There were significant differences between the SWA and IC, except in the group that ran at 9 km·h-1 (>9 METs). Bland-Altman analysis showed a BIAS of 1.56 METs (±1.83 METs) and limits of agreement (LOA) at 95% of -2.03 to 5.16 METs. There were indications of heteroscedasticity (R2 =0.03; P<0.05). Analysis of the receiver operating characteristic (ROC) curves showed that the SWA seems to be not sensitive enough to estimate the level of EE at highest intensities. CONCLUSIONS: The SWA is not as precise in estimating EE as IC, but it could be a useful tool to determine levels of EE at low intensities.

Circulating leptin and adiponectin concentrations in healthy exceptional longevity.

People reaching exceptional longevity free of major age-related diseases represent the paradigm of successful aging. Adipose tissue function declines as we age, potentially resulting in changes of circulating adipokines (e.g., leptin and adiponectin). Here, we measured circulating levels of leptin and adiponectin in healthy centenarians (n=81; 100-104 years) and younger elderly controls (n=46; 70-80 years). Centenarians had significant higher serum levels of leptin compared with controls (p<0.001), whereas no significant differences were observed for adiponectin. Further research including also other blood variables will be needed to elucidate whether high leptin levels could serve as a hallmark of healthy exceptional longevity.

Impact of gestational risk factors on maternal cardiovascular system.

BACKGROUND: Scarce evidence is available on the potential cardiovascular abnormalities associated with some common gestational complications. We aimed to analyze the potential maternal cardiac alterations related to gestational complications, including body mass index (BMI) >25 kg/m(2), gaining excessive weight, or developing antenatal depression. METHODS: The design of this study was a secondary analysis of a randomized controlled trial. Echocardiography was performed to assess cardiovascular indicators of maternal hemodynamic, cardiac remodeling and left ventricular (LV) function in 59 sedentary pregnant women at 20 and 34 weeks of gestation. RESULTS: Starting pregnancy with a BMI >25 kg/m(2), gaining excessive weight, and developing antenatal depression had no cardiovascular impact on maternal health (P value >0.002). Depressed women were more likely to exceed weight gain recommendations than non-depressed women (P value <0.002). CONCLUSIONS: The evaluated gestational complications seem not to induce cardiovascular alterations in hemodynamic, remodeling and LV function indicators. However, developing antenatal depression increases the risk of an excessive weight gain. This finding is potentially important because excessive weight gain during pregnancy associates with a higher risk of cardiovascular diseases (CVD) later in life.