The purpose of this study was: (1) to compare body volume (BV) estimated from a 2-dimensional (2D) image analysis program (BV
), and a dual-energy x-ray absorptiometry (DXA) equation (BV
) to an ...underwater weighing (UWW) criterion (BV
); (2) to compare relative adiposity (%Fat) derived from a 3-compartment (3C) model using BV
(%Fat
), and a 4-compartment (4C) model using BV
(%Fat
) to a 4C criterion model using BV
(%Fat
).
Forty-eight participants were included (60% male, 22.9 ± 5.0 years, 24.2 ± 2.6 kg/m
). BV
was derived using a single digital image of each participant taken from the rear/posterior view. DXA-derived BV was calculated according to Smith-Ryan et al. Bioimpedance spectroscopy and DXA were used to measure total body water and bone mineral content, respectively, in the 3C and 4C models. A standardized mean effect size (ES) assessed the magnitude of differences between models with values of 0.2, 0.5, and 0.8 for small, moderate, and large differences, respectively. Data are presented as mean ± standard deviation.
Near-perfect correlation (r = 0.998, p < 0.001) and no mean differences (p = 0.267) were observed between BV
(69.6 ± 11.5 L) and BV
(69.5 ± 11.4 L). No mean differences were observed between %Fat
and the %Fat
criterion (p = 0.988). Small mean differences were observed between %Fat
and %Fat
(ES = 0.2, p < 0.001). %Fat
exhibited smaller SEE and TE, and tighter limits of agreement than %Fat
.
The 2D image analysis program provided an accurate and non-invasive estimate of BV, and subsequently %Fat within a 3C model in generally healthy, young adults.
Abstract Objectives The purpose of this study was to evaluate cardiac-parasympathetic and psychometric responses to competition preparation in collegiate sprint-swimmers. Additionally, we aimed to ...determine the relationship between average vagal activity and its daily fluctuation during each training phase. Design Observational. Methods Ten Division-1 collegiate sprint-swimmers performed heart rate variability recordings (i.e., log transformed root mean square of successive RR intervals, lnRMSSD) and completed a brief wellness questionnaire with a smartphone application daily after waking. Mean values for psychometrics and lnRMSSD (lnRMSSDmean ) as well as the coefficient of variation (lnRMSSDcv ) were calculated from 1 week of baseline (BL) followed by 2 weeks of overload (OL) and 2 weeks of tapering (TP) leading up to a championship competition. Results Competition preparation resulted in improved race times ( p < 0.01). Moderate decreases in lnRMSSDmean , and Large to Very Large increases in lnRMSSDcv , perceived fatigue and soreness were observed during the OL and returned to BL levels or peaked during TP ( p <0.05). Inverse correlations between lnRMSSDmean and lnRMSSDcv were Very Large at BL and OL ( p <0.05) but only Moderate at TP ( p >0.05). Conclusions OL training is associated with a reduction and greater daily fluctuation in vagal activity compared with BL, concurrent with decrements in perceived fatigue and muscle soreness. These effects are reversed during TP where these values returned to baseline or peaked leading into successful competition. The strong inverse relationship between average vagal activity and its daily fluctuation weakened during TP.
The purpose of this study was to evaluate the agreement of the vagal-related heart rate variability index, log-transformed root mean square of successive R-R intervals (lnRMSSD), measured under ...ultra-short-term conditions (< 60 seconds) with conventional longer term recordings of 5 minutes in collegiate athletes under resting and post-exercise conditions. Electrocardiographic readings were collected from twenty-three athletes within 5-minute segments at rest and at 25-30 minutes of supine recovery following a maximal exercise test. From each 5-minute segment, lnRMSSD was recorded as the criterion measure. Within each 5-minute segment, lnRMSSD was also determined from randomly selected ultra-short-term segments of 10-, 30-, and 60-seconds in length, which were compared to the criterion. When compared to the criterion measures, the significant intraclass correlation (from 0.98 to 0.81, p < 0.05) and typical error (from 0.11 to 0.34) increased as ultra-short-term measurement duration decreased (i.e., from 60 seconds to 10 seconds). In addition, the limits of agreement (Bias ± 1.98 SD) increased as ultra-short-term lnRMSSD duration decreased as follows: 0.00 ± 0.22 ms, -0.07 ± 0.41 ms, -0.20 ± 0.94 ms for the 60-, 30-, and 10-second pre-exercise segments, respectively, and -0.15 ± 0.39 ms, -0.14 ± 0.53 ms, -0.12 ± 0.76 ms for the 60-, 30-, and 10-second post-exercise segments, respectively. This study demonstrated that as ultra-short-term measurement duration decreased from 60 seconds to 10 seconds, the agreement to the criterion decreased. Therefore, 60 seconds appears to be an acceptable recording time for lnRMSSD data collection in collegiate athletes. Key PointsThe log-transformed root mean square of successive R-R intervals (lnRMSSD) is a vagal-related heart rate variability index that has become a promising method for monitoring individual adaptation to training when measured during resting or post-exercise conditions.This study demonstrated that lnRMSSD of the 60-second electrocardiogram segments could likely serve as an alternative to traditional 5-minute measures in resting and exercise recovery conditions.Due to the current results in athletes and previous investigation involving non-athletes, the utility of ultra-sound-term lnRMSSD measures, especially 60 seconds in duration, within field setting for monitoring athletes at rest and in response to stress appears promising.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
ABSTRACTFlatt, AA and Esco, MR. Evaluating individual training adaptation with Smartphone-derived heart rate variability in a collegiate female soccer team. J Strength Cond Res 30(2)378–385, ...2016—Monitoring individual responses throughout training may provide insight to coaches regarding how athletes are coping to the current program. It is unclear if the evolution of heart rate variability (HRV) throughout training in team-sport athletes can be useful in providing early indications of individual adaptation. This study evaluated relationships between changes in resting cardiac autonomic markers derived from a novel smartphone device within the first 3 weeks of a 5-week conditioning program and the eventual change in intermittent running performance at week 5 among 12 collegiate female soccer players. Change variables from weeks 1 to 3 of the weekly mean and weekly coefficient of variation for resting heart rate (INCREMENTRHRmean and INCREMENTRHRcv, respectively) and log-transformed root mean square of successive R-R intervals multiplied by 20 (INCREMENTLn rMSSDmean and INCREMENTLn rMSSDcv, respectively) were compared with changes in Yo-Yo Intermittent Recovery Test Level 1 performance (INCREMENTYo-Yo). A very large and significant correlation was found between INCREMENTYo-Yo and INCREMENTLn rMSSDcv (r = −0.74; p = <0.01) and a large nonsignificant correlation was found with INCREMENTLn rMSSDmean (r = 0.50; p = 0.096). This study suggests that a decrease in Ln rMSSDcv within the first 3 weeks of training is a favorable response, indicative of positive adaptation. Collecting daily HRV data with a smartphone application using ultrashort HRV measures seems useful for athlete monitoring.
Abstract
Flatt, AA, Hornikel, B, Nakamura, FY, and Esco, MR. Effect of competitive status and experience on heart rate variability profiles in collegiate sprint-swimmers.
J Strength Cond Res
36(10): ...2898–2904, 2022—Interindividual differences in training history may be a determinant of heart rate variability (HRV) profiles in collegiate sprint-swimmers and may account for differences observed between elite and subelite athletes. We therefore compared HRV profiles among national-level and conference-level sprint-swimmers while accounting for individual swim-training history. Twenty-eight short-distance swimmers (18 men and 10 women) recorded postwaking HRV throughout a 4-week standardized training period. The 4-week mean (
M
) and coefficient of variation (
CV
, a marker of daily fluctuation) were calculated for resting heart rate (RHR) and the natural logarithm of the root mean square of successive differences (LnRMSSD). Swimmers were categorized as national-level (
n
= 12) or conference-level (
n
= 16) competitors. Years of competitive experience was documented for each individual to index training history.
p
< 0.05 was considered statistically significant. No sex-related differences were observed for any variables (
p
> 0.05). LnRMSSD
M
(effect size ES = 0.95), LnRMSSD
CV
(ES = −1.18), RHR
CV
(ES = −1.05), and competitive experience (ES = 1.23) differed between status groups (
p
< 0.05). Accounting for multicollinearity between competitive experience and LnRMSSD variables (
p
< 0.05), competitive experience remained associated with LnRMSSD
M
(
r
= 0.44,
p
= 0.02). With competitive experience included as a covariate, differences in LnRMSSD
M
between status groups disappeared (
p
> 0.05, ES = 0.31). National-level swimmers exhibit higher and more stable LnRMSSD than that of their conference-level teammates throughout standardized training. Differences in trend characteristics were attributed to training age. This information may assist practitioners with interpreting interindividual differences in HRV profiles throughout training periods among a mixed roster of athletes.
Summary
Resting heart rate variability (HRV) is a potentially useful marker to consider for monitoring training status in athletes. However, traditional HRV data collection methodology requires a ...5‐min recording period preceded by a 5‐min stabilization period. This lengthy process may limit HRV monitoring in the field due to time constraints and high compliance demands of athletes. Investigation into more practical methodology for HRV data acquisitions is required. The aim of this study was to determine the time course for stabilization of ECG‐derived lnRMSSD from traditional HRV recordings. Ten‐minute supine ECG measures were obtained in ten male and ten female collegiate cross‐country athletes. The first 5 min for each ECG was separately analysed in successive 1‐min intervals as follows: minutes 0–1 (lnRMSSD0–1), 1–2 (lnRMSSD1–2), 2–3 (lnRMSSD2–3), 3–4 (lnRMSSD3–4) and 4–5 (lnRMSSD4–5). Each 1‐min lnRMSSD segment was then sequentially compared to lnRMSSD of the 5‐ to 10‐min ECG segment, which was considered the criterion (lnRMSSDCriterion). There were no significant differences between each 1‐min lnRMSSD segment and lnRMSSDCriterion, and the effect sizes were considered trivial (ES ranged from 0·07 to 0·12). In addition, the ICC for each 1‐min segment compared to the criterion was near perfect (ICC values ranged from 0·92 to 0·97). The limits of agreement between the prerecording values and lnRMSSDCriterion ranged from ±0·28 to ±0·45 ms. These results lend support to shorter, more convenient ECG recording procedures for lnRMSSD assessment in athletes by reducing the prerecording stabilization period to 1 min.
ABSTRACTDobbs, WC, Tolusso, DV, Fedewa, MV, and Esco, MR. Effect of postactivation potentiation on explosive vertical jumpa systematic review and meta-analysis. J Strength Cond Res 33(7)2009–2018, ...2019—The primary aim of this systematic review and meta-analysis was to quantify the magnitude of the effect of postactivation potentiation (PAP) on explosive vertical power while accounting for the nesting of multiple effects within each study. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement (PRISMA). Original research articles published by January 18, 2018, were located using an electronic search of 4 databases and yielded 759 original publications. Data were extracted and independently coded by 2 authors (W.C.D. and D.V.T.). The standardized mean effect size (ES) was calculated by subtracting the pre-treatment mean from the post-treatment mean and dividing by the pooled SD, adjusting for small sample bias. Multilevel random-effects model was used to aggregate a mean ES and 95% confidence interval (CI) for PAP on vertical jump performance. The cumulative results of 179 effects gathered from 36 studies indicate that PAP does not improve vertical jump performance (ES = 0.08, 95% CI −0.04 to 0.21, p = 0.197), with moderate heterogeneity. Moderator analysis indicated that rest intervals between 3 and 7 minutes provided favorable performance outcomes (ES = 0.18, 95% CI 0.05 to 0.31, p = 0.007). Conversely, rest intervals less than 3 minutes (ES = −0.15, 95% CI −0.31 to 0.01, p = 0.052) or performing isometric contractions (ES = −0.52, 95% CI −0.89 to −0.14, p = 0.007) may be detrimental to performance. Meta-regression indicated that rest interval was the only moderator significantly associated with ES (β = −0.04, 95% CI −0.57 to −0.02, R = 14.31%, p < 0.001). When appropriate PAP guidelines are followed, an increase in vertical jump performance may be achieved.
ABSTRACTWilliams, TD, Esco, MR, Fedewa, MV, and Bishop, PA. Bench press load-velocity profiles and strength after overload and taper microcyles in male powerlifters. J Strength Cond Res ...34(12)3338–3345, 2020—The purpose of this study was to quantify the effect of an overload microcycle and taper on bench press velocity and to determine if the load-velocity relationship could accurately predict 1-repetition maximum (1RM). Twelve male powerlifters participated in resistance training structured into an introduction microcycle, overload microcycle (PostOL), and taper (PostTP). At the end of each microcycle, subjects completed a bench press for 1RM assessment consisting of warm-up sets at 40, 55, 70, and 85% of a previously established 1RM. The mean concentric velocity (MCV) was recorded during each warm-up set. A predicted 1RM (p1RM) was calculated using an individualized load-velocity profile (LVP). The average MCV decreased after PostOL (0.66 ± 0.07 m·s) compared with baseline (BL) (p = 0.003; 0.60 ± 0.11 m·s) but increased after PostTP (0.67 ± 0.09 m·s). One-repetition maximum increased from PostOL (146.7 ± 19.8 kg) to PostTP (p = 0.002; 156.1 ± 21.0 kg), with no differences observed between other test sessions (p > 0.05). Bland-Altman analysis indicated that p1RM was consistently higher than measured 1RM (3.4–7.8 kg), and the limits of agreement were extremely wide. However, very large to near perfect correlations (r = 0.89 to 0.96) were observed between p1RM and 1RM during BL, PostOL, and PostTP. The load-velocity relationship established from submaximal sets did not accurately predict 1RM, but MCV was affected by changes in weekly training loads. Velocity-based measurements seem to be more sensitive to changes in training loads than maximal strength.
Purpose
The study aimed to investigate the effect of repeated cold-water immersion (CWI) after high-intensity interval exercise sessions on cardiac-autonomic modulation, neuromuscular performance, ...muscle damage markers, and session internal load.
Methods
Twenty-one participants underwent five sessions of high-intensity interval exercise (6–7 bouts of 2 min; pause of 2 min) over a two-week period. Participants were allocated randomly into either a group that underwent CWI (11-min; 11 °C) or a group that performed passive recovery after each exercise session. Before the exercise sessions were performed, countermovement jump (CMJ) and heart rate variability were recorded (i.e., rMSSD, low and high frequency power and its ratio, SD1 and SD2). Exercise heart rate was calculated by recording the area under the curve (AUC) response. Internal session load was evaluated 30 min after each session. Blood concentrations of creatine kinase and lactate dehydrogenase were analyzed before the first visit and 24 h after the last sessions.
Results
The CWI group presented higher rMSSD than the control group at each time point (group-effect
P
= 0.037). The SD1 was higher in CWI group when compared to the control group following the last exercise session (interaction
P
= 0.038). SD2 was higher in CWI group compared to the control group at each time point (group-effect
P
= 0.030). Both groups presented equal CMJ performance (
P
> 0.05), internal load (group-effect P = 0.702; interaction
P
= 0.062), heart rate AUC (group-effect
P
= 0.169; interaction
P
= 0.663), and creatine kinase and lactate dehydrogenase blood concentrations (
P
> 0.05).
Conclusion
Repeated post-exercise CWI improves cardiac-autonomic modulation. However, no differences in neuromuscular performance, muscle damage markers, or session internal load were demonstrated between the groups.
ABSTRACTNakamura, FY, Antunes, P, Nunes, C, Costa, JA, Esco, MR, and Travassos, B. Heart rate variability changes from traditional vs. ultra–short-term recordings in relation to preseason training ...load and performance in futsal players. J Strength Cond Res 34(10)2974–2981, 2020—The aims of this study were to analyze heart rate variability (HRV) changes in futsal players during preseason training using both “criterion” (10-minute) and ultra-shortened (2-minute) measures, and to determine whether they were related to changes in the Yo-Yo Intermittent Recovery Test, level 1 (Yo-Yo IR1) performance and accumulated training load (TL). Eleven male competitive futsal players (age = 25.19 ± 4.70 years; body mass = 73.15 ± 11.70 kg; and height = 176.90 ± 5.01 cm) volunteered for the study. Data collection took place during the first to the fourth weeks of preseason training. Training load was monitored with session ratings of perceived exertion. The total distance (TD) covered during the Yo-Yo IR1 was recorded during week 1 and week 4. Heart rate variability was measured through the log-transformed root mean square of successive normal-to-normal interval differences using the ultra-short analysis, with its weekly mean (lnRMSSDM) and coefficient of variation (lnRMSSDCV) recorded, and by means of the criterion method (weeks 1 and 4). lnRMSSDM was likely higher at week 4 compared with week 1 using both criterion and ultra-short recordings. Moderate-to-large correlations were found between changes in the lnRMSSDM and lnRMSSDCV values and changes in TL and TD (r values ranged from −0.48 to 0.65). Changes in ultra-short HRV measures (i.e., increase in lnRMSSDM and decrease in lnRMSSDCV) during futsal preseason were associated with increased performance. The players who accumulated higher perceived TLs displayed smaller improvements in the Yo-Yo IR1 performance and HRV.
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