Is bioelectrical impedance spectroscopy accurate in estimating changes in fat-free mass in judo athletes?

Abstract

Bioelectrical impedance spectroscopy (BIS) provides an affordable and practical assessment of fat-free mass (FFM). However, little information is available on the assessment of changes in fat-free mass in top-level athletes using BIS. The aim of this study was to examine the accuracy of BIS in tracking changes in fat-free mass of elite male judo athletes from a period of weight stability to just before competition, using the four-compartment model (4C model) as reference method. In total, 27 elite male judo athletes (age 22.2 ± 2.8 years) were evaluated. Measures of body volume assessed by air displacement plethysmography, bone mineral content by dual-energy X-ray absorptiometry, and total-body water assessed with deuterium dilution were used in a 4C model. Fat-free mass was also assessed by BIS (FFM_BIS). Changes in FFM_BIS were not significantly different from measured by the reference method (P = 0.000). Furthermore, the r ² was 0.62 and the standard error of the estimate was 1.03 kg. The limits of agreement ranged from ?3.36 to 2.59 kg with no bias observed. These findings demonstrate the viability of BIS as a valid tool for tracking fat-free mass in elite male judo athletes. However, based on the wide limits of agreement observed, BIS is less valid at an individual level for tracking fat-free mass in these athletes.     

Is bioelectrical impedance spectroscopy accurate in estimating changes in fat-free mass in judo athletes?

Abstract Bioelectrical impedance spectroscopy (BIS) provides an affordable and practical assessment of fat-free mass (FFM). However, little information is available on the assessment of changes in fat-free mass in top-level athletes using BIS. The aim of this study was to examine the accuracy of BIS in tracking changes in fat-free mass of elite male judo athletes from a period of weight stability to just before competition, using the four-compartment model (4C model) as reference method. In total, 27 elite male judo athletes (age 22.2?±?2.8 years) were evaluated. Measures of body volume assessed by air displacement plethysmography, bone mineral content by dual-energy X-ray absorptiometry, and total-body water assessed with deuterium dilution were used in a 4C model. Fat-free mass was also assessed by BIS (FFM(BIS)). Changes in FFM(BIS) were not significantly different from measured by the reference method (P?=?0.000). Furthermore, the r (2) was 0.62 and the standard error of the estimate was 1.03 kg. The limits of agreement ranged from -3.36 to 2.59 kg with no bias observed. These findings demonstrate the viability of BIS as a valid tool for tracking fat-free mass in elite male judo athletes. However, based on the wide limits of agreement observed, BIS is less valid at an individual level for tracking fat-free mass in these athletes.     

Resistance training promotes increase in intracellular hydration in men and women

Abstract

The main purpose of the present study was to investigate the effect of 16 weeks of resistance training (RT) on body water in men and women. Thirty men (22.7 ± 4.4 years, 68.4 ± 9.0 kg and 174.5 ± 6.6 cm) and 34 women (22.7 ± 4.1 years, 58.8 ± 11.9 kg and 162.6 ± 6.2 cm) underwent progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, that consisted of 10–12 whole body exercises with 3 sets of 8–12 repetitions maximum. Total body water, TBW (intracellular water, ICW and extracellular water, ECW compartments) and skeletal muscle mass (SMM) were assessed using a spectral bioelectrical impedance device (Xitron 4200 Bioimpedance Spectrum Analyzer). TBW, ICW compartment and SMM increased significantly (P < 0.05) over time in men (+7.5%, +8.2% and +4.2%, respectively) and women (+7.6%, +11.0% +3.9%, respectively), with no sex by time interaction (P > 0.05). We conclude that progressive RT promotes an increase in body water, principally by intracellular content; however, the hydration status is not influenced by sex.     

Evaluation of body composition with bioimpedence. A comparison between athletic and non-athletic children

Purpose: Conventional Bioelectrical Impedance Analysis (BIA) or Bioelectrical Impedance Vector Analysis (BIVA) can provide direct evaluations of body composition. The purpose of this study was to evaluate lean and fat mass (FM), and hydration of children involved in daily competitive sports. Methods: 190 non-athletic [8.2–10.5 years] and 29 competitive children [8.0–10.5 years] were enrolled. They were evaluated: at baseline (t0), 6 months (t1) and one year (t2). Anthropometric, BIA and BIVA, lean and FM, and hydration evaluations were performed. Results: Resistance (R/h) and reactance (Xc/h) were lower at t0 in competitive individuals when compared to controls. Xc/h (+3.28) significantly increases in competitive when compared to non-competitive individuals (+0.66, p for difference: 0.011), while phase angle (PA) was lower at t0 (5.72 vs. 6.17, p?<?.001) and after 6 months (p?=?.001). Total body water adjusted for height (TBW/h) significantly increased only in non-athletes (+0.50?±?0.13, p?<?.001) between t0 and t1. At t1, extracellular water (ECW) significantly decreased (p?=?.026) in the two groups: ?0.45?±?0.19% in non-competitive, ?1.63?±?0.49% in competitive subjects, while intracellular water (ICW) increased. At one-year follow-up (t2), there were no statistically significant differences in R/h, Xc/h and PA in competitive individuals when compared to baseline and t1. Furthermore, we observed at t2 that hours/week of training, age, male gender and body mass index can influence FFM/h and FM/h in both competitive and non-competitive subjects. In particular, a direct correlation was for hours/week and FFM/h, inverse for hours/week and FM/h. Conclusions: Body mass index does not allow evaluating differences in lean body mass and FM between athletes and non-athletes. BIA and BIVA can give more reliable details about body composition differences in competitive adolescents and non-competitive, outlining a progressive decline in ECW and increase in ICW without affecting TBW composition of athletes.     

Kinematic comparison of the seoi-nage judo technique between elite and college athletes

This study sought to identify biomechanical factors that determine fast and skilful execution of the seoi-nage (shoulder throw) technique by comparing kinematics between elite and college judo athletes. Three-dimensional motion data were captured using a VICON-MX system with 18 cameras operating at 250 Hz as three male elite and seven male college judo athletes performed seoi-nage. No significant difference was found in motion phase time of the turning phase between the two groups, indicating that motion phase time is not necessarily a factor contributing quickness in seoi-nage. The maximum relative velocity of the whole body centre of mass along the anterior–posterior direction was significantly greater in the elite athletes (2.74 ± 0.33 m/s) than in the college athletes (1.62 ± 0.47 m/s) during the turning phase (p = 0.023). The overall angular velocity of the body part lines, particularly the arm line, tended to be greater in the elite athletes (p = 0.068). The results imply that the velocity of the thrower relative to the opponent in the forward drive and turning motion reflects high skill seoi-nage. Coaches should recognise the relative forward velocity as a factor that may contribute to a successful seoi-nage when teaching the judo throw technique.     

No effect of HMB or α-HICA supplementation on training-induced changes in body composition

β-hydroxy-β-methylbutyrate (calcium: HMB-Ca and free acid: HMB-FA) and α-hydroxyisocaproic acid (α-HICA) are leucine metabolites that have been proposed to improve body composition and strength when combined with resistance exercise training (RET). In this double-blind randomized controlled pragmatic trial, we evaluated the effects of off-the-shelf supplements: α-HICA, HMB-FA and HMB-Ca, on RET-induced changes in body composition and performance. Forty men were blocked randomized to receive α-HICA (n?=?10, fat-free mass [FFM]?=?62.0?±?7.1?kg), HMB-FA (n?=?11, FFM?=?62.7?±?10.5?kg), HMB-Ca (n?=?9, FFM?=?65.6?±?10.1?kg) or placebo (PLA; n?=?10, FFM?=?64.2?±?5.7?kg). The training protocol consisted of a whole-body resistance training routine, thrice weekly for 8 weeks. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and total body water (TBW) by whole-body bioimpedance spectroscopy (BIS), both at baseline and at the end of weeks 4 and 8. Time-dependent changes were observed for increase in trunk FFM (p?相似文献   

Adolescent elite Kenyan runners are at risk for energy deficiency,menstrual dysfunction and disordered eating

Limited data are available on the female athlete triad (Triad) in athletes from minority groups. We explored subclinical and clinical Triad components amongst adolescent elite Kenyan athletes (n = 61) and non-athletes (n = 49). Participants completed demographic, health, sport and menstrual history questionnaires as well as a 5-day weighed dietary record and exercise log to calculate energy availability (EA). Ultrasound assessed calcaneus bone mineral density (BMD). Eating Disorder Inventory subscales and the Three-Factor Eating Questionnaire’s cognitive dietary restraint subscale measured disordered eating (DE). EA was lower in athletes than non-athletes (36.5 ± 4.5 vs. 39.5 ± 5.7 kcal ? kg FFM^?1 ? d^?1, P = 0.003). More athletes were identified with clinical low EA (17.9% vs. 2.2%, OR = 9.5, 95% CI 1.17–77, P = 0.021) and clinical menstrual dysfunction (32.7% vs. 18.3%, χ² = 7.1, P = 0.02). Subclinical (75.4% vs. 71.4%) and clinical DE (4.9% vs. 10.2%, P = 0.56) as well as BMD were similar between athletes and non-athletes. More athletes had two Triad components than non-athletes (8.9% vs. 0%, OR = 0.6, 95% CI 0.5–6.9, P = 0.05). Kenyan adolescent participants presented with one or more subclinical and/or clinical Triad component. It is essential that athletes and their entourage be educated on their energy needs including health and performance consequences of an energy deficiency.     

Reference power values for the jump squat exercise in elite athletes: A multicenter study

ABSTRACT

The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg^?1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg^?1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg^?1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s^?1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.     

Reliability of lower limb biomechanics in two sport-specific sidestep cutting tasks

The purpose of this study was to assess the within- and between-session reliability of lower limb biomechanics in two sport-specific sidestep cutting tasks performed by elite female handball and football (soccer) athletes. Moreover, we aimed at determining the minimum number of trials necessary to obtain a reliable measure. Nineteen elite female handball and 22 elite female football (soccer) athletes (M ± SD: 22 ± 4 yrs old, 168 ± 5 cm, 66 ± 8 kg) were tested. The reliability was quantified by intra-class correlations (ICCs), typical error and Spearman’s rank correlation. Only minor improvements in ICC values were seen when increasing the number of trials from 3 to 5. Based on trials 1–3, all variables showed good to excellent within-session reliability (M ICC: 0.91, 95% CI: 0.89–0.93), fair to good between-session reliability (M ICC: 0.73, 95% CI: 0.70–0.76), moderately positive between-session rank correlation coefficients (M: 0.72, 95% CI: 0.69–0.76). A few frontal plane biomechanical variables displayed lower between-session reliability in the football task compared with the handball task. The moderately positive between-session ranking and practically small typical error implies that the measurements could reliably reproduce the ranking of individuals in multiple-session studies. Adequate reliability could be attained from 3 trials, with only minor improvements when adding more trials.     

A biomechanical investigation of right-forward lunging step among badminton players

This study presents the kinematics and plantar pressure characteristics of eight elite national-level badminton athletes and eight recreational college-level badminton players while performing a right-forward lunge movement in a laboratory-simulated badminton court. The hypothesis was that recreational players would be significantly different from elite players in kinematics and plantar pressure measures. Vicon^® motion capture and Novel^® insole plantar pressure measurement were simultaneously taken to record the lower extremity kinematics and foot loading during stance. Recreational players showed significantly higher peak pressure in the lateral forefoot (P = 0.002) and force time integral in the lateral forefoot (P = 0.013) and other toes (P = 0.005). Elite athletes showed higher peak pressure in the medial forefoot (P = 0.003), hallux (P = 0.037) and force time integral in the medial forefoot (P = 0.009). The difference in landing techniques for the lunge step between elite athletes and recreational players was observed with peak ankle eversion (?38.2°±2.4° for athletes and ?11.1°±3.9° for players, P = 0.015); smaller knee range of motion in the coronal and transverse planes, with differences in peak knee adduction (28.9°±6.8° for athletes and 15.7°±6.2° for players, P = 0.031); peak knee internal rotation (20.3°±1.3° for athletes and 11.8°±3.2° for players, P = 0.029) and peak hip flexion (77.3°±4.1° for athletes and 91.3°±9.3° for players, P = 0.037).     

Body composition characteristics of elite Australian rugby union athletes according to playing position and ethnicity

This study describes the body composition traits of modern-day elite rugby union athletes according to playing position and ethnicity. Thirty-seven international Australian rugby athletes of Caucasian and Polynesian descent undertook body composition assessment using dual-energy X-ray absorptiometry and surface anthropometry. Forwards were significantly taller, heavier and had a greater total fat mass and lean mass than backs. Backs displayed a higher percentage lean mass and lower sum of seven skinfolds and percentage fat mass. While no whole body composition differences were seen between ethnicities, significant regional differences were observed. In the periphery (arm and leg) regions, Polynesians had a greater proportion of fat mass (53.1% vs. 51.3%, P = 0.052, d = 0.5) and lean mass (49.7% vs. 48.6%, P = 0.040, d = 0.9), while in the trunk region a lower proportion of fat mass (37.2% vs. 39.5%, P = 0.019, d = 0.7) and lean mass (45.6% vs. 46.8%, P = 0.020, d = 1.1). Significant differences were also seen between Caucasian and Polynesian forwards in leg lean mass (31.4 kg vs. 35.9 kg, P = 0.014, d = 2.4) and periphery lean mass (43.8 kg vs. 49.6 kg, P = 0.022, d = 2.4). Elite Polynesian rugby athletes have different distribution patterns of fat mass and lean mass compared to Caucasians, which may influence their suitability for particular positions.     

Caffeine improves muscular performance in elite Brazilian Jiu-jitsu athletes

Scientific information about the effects of caffeine intake on combat sport performance is scarce and controversial. The aim of this study was to investigate the effectiveness of caffeine to improve Brazilian Jiu-jitsu (BJJ)-specific muscular performance. Fourteen male and elite BJJ athletes (29.2?±?3.3?years; 71.3?±?9.1?kg) participated in a randomized double-blind, placebo-controlled and crossover experiment. In two different sessions, BJJ athletes ingested 3?mg?kg^?1 of caffeine or a placebo. After 60?min, they performed a handgrip maximal force test, a countermovement jump, a maximal static lift test and bench-press tests consisting of one-repetition maximum, power-load, and repetitions to failure. In comparison to the placebo, the ingestion of the caffeine increased: hand grip force in both hands (50.9?±?2.9 vs. 53.3?±?3.1?kg; respectively p?p?=?.02), and time recorded in the maximal static lift test (54.4?±?13.4 vs. 59.2?±?11.9?s; p?p?=?.02), maximal power obtained during the power-load test (750.5?±?154.7 vs. 826.9?±?163.7?W; p?p?=?.04). In conclusion, the pre-exercise ingestion of 3?mg?kg^?1 of caffeine increased dynamic and isometric muscular force, power, and endurance strength in elite BJJ athletes. Thus, caffeine might be an effective ergogenic aid to improve physical performance in BJJ.     

Fluid balance and hydration assessment during the weight-stable preparation phase in elite youth boxers

This study investigated (i) the prevalence of hypohydration and (ii) association between urinary indices of hydration status and confounding factors (e.g., urine protein content, water intake) in elite youth boxers during their weight-stable phase before competition. Sixteen national champion boxers (all male, 17 ± 1 y) were measured on 3 occasions (baseline, day 3, day 10), 30-day prior to competition. Body mass, total body water, urine specific gravity (USG), osmolality (UOSM) and total protein content (TPC) were evaluated to determine hydration status and fluid balance. Overall macronutrient and water intake were assessed using dietary records. Both UOSM and USG increased from day 3 to day 10 by 16% and 0.4% (P < 0.001), despite athletes being in their weight-stability period, and regardless of ad libitum fluid intake. Hypohydration was universally prevalent among all athletes on both test days with USG: 1.027 ± 0.003 g · mL^?1 and UOSM: 1035 ± 108 mOsmol · kg^?1. An inverse association between mean UOSM values and mean water intake was observed (R = ?0.52, P = 0.04), while TPC was not associated with any urinary dehydration markers (USG, P = 0.51; UOSM, P = 0.61). The present outcomes find that the most prevalent urinary dehydration markers used to classify hydration status in competition exhibit large variability, even during weight-stable periods.     

Bone health in elite Kenyan runners

Impact loading in athletes participating in various sports has been positively associated with increased bone mineral density (BMD), but this has not been investigated in elite Kenyan runners. Body composition and site-specific BMD measures quantified with dual x-ray absorptiometry were measured in 15 elite male Kenyan runners and 23 apparently healthy South African males of different ethnicities. Training load and biomechanical variables associated with impact loading, such as joint stiffness, were determined in the elite Kenyan runners. Greater proximal femur (PF) BMD (g · cm^?2) was higher (P = 0.001, ES = 1.24) in the elite Kenyan runners compared with the controls. Six of the 15 (40%) Kenyan runners exhibited lumbar spine (LS) Z-Scores below ?2.0 SD, whereas this was not found in the apparently healthy controls. PFBMD was associated with training load (r = 0.560, P = 0.003) and ankle (r = 0.710, P = 0.004) and knee (r = 0.546, P = 0.043) joint stiffness. Elite Kenyan runners exhibit greater PFBMD than healthy controls, which is associated with higher training load and higher joint stiffness. Our results reaffirm the benefits of impact loading on BMD at a weight-bearing site, while a high prevalence of low LSBMD in the elite Kenyan runners is hypothesised to be the result of a mismatch between energy intake and high training load. Future research investigating energy availability in Kenyan runners and the possible association with musculoskeletal injury should be investigated.     

Protective role of 17-β-estradiol towards IL-6 leukocyte expression induced by intense training in young female athletes

Abstract

Exercise performed at a competitive level could deeply modify the immune system and the cytokine response of athletes. In this report, we demonstrated that young elite female artistic gymnasts (n = 16; age: 9–15 years) showed an increase of interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) mRNA expression in blood mononuclear cells (PBMCs), in comparison to girls performing the same sport at a recreational level (n = 16; age: 10–15 years). The increase of IL-6 and TNF-α mRNAs appeared to be directly linked to the intensity and duration of the training. Moreover, in elite athletes engaged in artistic gymnastics or in synchronised swimming (n =34; age: 9–15 years), IL-6 gene expression appeared to be modulated by the levels of circulating oestrogens: pre-pubertal athletes (n = 20; age: 11 ± 1 years) revealed a higher increase in IL-6 than pubertal athletes (n = 14; age: 14 ± 1.6 years). In pre-pubertal athletes, body mass index (BMI) percentile was inversely correlated with the increase of both IL-6 and TNF-α. The consequence of these events was the shift of the cytokine profile towards a pro-inflammatory status. These modifications, induced by training performed at an elite level, might negatively affect the growth of female children athletes.     

Muscle activation characteristics in cross-country skiers with a history of anterior compartment pain

A large proportion of elite cross-country skiers suffer from chronic anterior compartment syndrome (CACS). This study used surface electromyograms (EMGs) to investigate whether differences existed in the activation characteristics of the tibialis anterior muscle between elite cross-country skiers with a history of anterior compartment pain (symptomatic group) and a pain-free control group. Based on self-reported pain symptoms, twelve young, national-level cross-country ski athletes were assigned to a symptomatic group (N = 5), a control group (N = 4), or analyzed individually if their diagnosis was not certain (N = 3). During skating, EMGs were recorded on five lower leg muscles. The relative increase in EMG power per step when increasing the effort level of skating was larger in the symptomatic group than in the control group for tibialis anterior (143 ± 12% vs. 125 ± 23%; Cohen's d = 1.17), peroneus longus (123 ± 24% vs. 107 ± 6%; d = 0.91), and gastrocnemius lateralis (167 ± 51% vs. 117 ± 12%; d = 1.64). The symptomatic group showed more power in the lower frequency bands of the tibialis anterior's EMG spectra (p < 0.001), whereas no group differences were found in other muscles (all p>0.2). Within the step cycle, these differences appeared in the swing phase and in the gliding phase during single leg support. The observed differences in the EMG spectra may serve as an early identification of athletes who are at risk of developing CACS.     

Repeated-sprint performance and plasma responses following beetroot juice supplementation do not differ between recreational,competitive and elite sprint athletes

Purpose: There is an ongoing debate whether highly trained athletes are less responsive to the ergogenic properties of nitrate. We assessed the effects of nitrate supplementation on plasma nitrate and nitrite concentrations and repeated-sprint performance in recreational, competitive and elite sprint athletes. Methods: In a randomized double-blinded cross-over design, recreational cyclists (n?=?20), national talent speed-skaters (n?=?22) and Olympic-level track cyclists (n?=?10) underwent two 6-day supplementation periods; 140?mL/d nitrate-rich (BR; ～800?mg/d) and nitrate-depleted (PLA; ～0.5?mg/d) beetroot juice. Blood samples were collected and three 30-s Wingate tests were performed. Results: Plasma nitrate and nitrite concentrations were higher following BR vs PLA (P?P?>?.10). Peak power over the three Wingates was not different between BR and PLA (1338?±?30 vs 1333?±?30 W; P?=?.62), and there was no interaction between treatment (BR-PLA) and Wingate number (1-2-3; P?=?.48). Likewise, mean power did not differ between BR and PLA (P?=?.86). In contrast, time to peak power improved by ～2.8% following BR vs PLA (P?=?.007). This improvement in BR vs PLA was not different between Wingate 1, 2 and 3. Moreover, the effects of BR vs PLA did not differ between sport levels for any Wingate parameter (all P?>?.30). Conclusion: The plasma and repeated-sprint performance responses to beetroot juice supplementation do not differ between recreational, competitive and elite sprint athletes. Beetroot juice supplementation reduces time to reach peak power, which may improve the capacity to accelerate during high-intensity and sprint tasks in recreational as well as elite athletes.     

Estimating fat-free mass in elite-level male rowers: a four-compartment model validation of laboratory and field methods

The purpose of this study was to investigate the accuracy of fat-free mass (FFM) estimates from two-compartment (2C) models including air displacement plethysmography (ADP), ultrasound (US), near-infrared interactance (NIR), and the Jackson and Pollock skinfold equation (SKF) against a criterion four-compartment (4C) model in elite male rowers. METHODS: Twenty-three elite-level male rowers (mean± SD; age 24.6 ± 2.2 years; stature: 191.4 ± 7.2 cm; mass: 87.2 ± 11.2 kg) participated in this investigation. All body composition assessments were performed on the same day in random order, except for hydrostatic weighing (HW), which was measured last. FFM was evaluated using a 4C model, which included total body water from bioimpedance spectroscopy, body volume from HW, and total body bone mineral via dual-energy X-ray absorptiometry. The major findings of the study were that the 2C models evaluated overestimated FFM and should be considered with caution for the assessment of FFM in elite male rowers. Future studies should use multiple-compartment models, with measurement of TBW and bone mineral content, for the estimation of FFM.