Article

Manipulation of Muscle Creatine and Glycogen Changes DXA Estimates of Body Composition

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Abstract

Purpose: We investigated the effects of manipulating muscle glycogen and creatine content independently and additively on DXA estimates of lean mass. Method: Eighteen well-trained male cyclists undertook a parallel group application of creatine loading (n=9) (20 g/d for 5 d loading; 3 g/d maintenance) or placebo (n=9) with crossover application of glycogen loading (12 v 6 g/kg BM/d for 48 h) as part of a larger study involving a glycogen-depleting exercise protocol. Body composition, total body water, muscle glycogen and creatine content were assessed via DXA, bioelectrical impedance spectroscopy and standard biopsy techniques. Changes in the mean were assessed using the following effect-size scale: >0.2 small, >0.6, moderate, >1.2 large and compared with the threshold for the smallest worthwhile effect of the treatment. Results: Glycogen loading, both with and without creatine loading, resulted in substantial increases in estimates of lean body mass (mean ± SD; 3.0 ± 0.7 % and 2.0 ± 0.9 %) and leg lean mass (3.1 ± 1.8 %and 2.6 ± 1.0 %) respectively. A substantial decrease in leg lean mass was observed following the glycogen depleting condition (-1.4 ± 1.6 %). Total body water showed substantial increases following glycogen loading (2.3 ± 2.3 %), creatine loading (1.4 ± 1.9 %) and the combined treatment (2.3 ± 1.1 %). Conclusions: Changes in muscle metabolites and water content alter DXA estimates of lean mass during periods in which minimal change in muscle protein mass is likely. This information needs to be considered in interpreting the results of DXA-derived estimates of body composition in athletes.

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... Technical error is influenced by quality control procedures, such as subject clothing (Fields et al., 2000;Vescovi et al., 2002), and positioning during assessment (Kerr et al., 2016;Lambrinoudaki et al., 1998;Tegenkamp et al., 2011), level of technical expertise (Hume & Marfell-Jones, 2008;Ruiz et al., 1971), and equipment calibration (Marfell-Jones et al., 2012). Biological variation may result from food and fluid ingestion or exercise prior to assessment and appears to influence most body composition methods, albeit to different degrees (Bone et al., 2017;Kerr et al., 2017). Other biological variables known to have an impact on estimates of body composition include body temperature and skin moisture (Fields et al., 2004), gastrointestinal contents (Bone et al., 2017), and muscle solutes (Rouillier et al., 2015). ...
... Biological variation may result from food and fluid ingestion or exercise prior to assessment and appears to influence most body composition methods, albeit to different degrees (Bone et al., 2017;Kerr et al., 2017). Other biological variables known to have an impact on estimates of body composition include body temperature and skin moisture (Fields et al., 2004), gastrointestinal contents (Bone et al., 2017), and muscle solutes (Rouillier et al., 2015). ...
... This is in agreement with previously reported results, a CV of 0.5% and 1.5%, respectively (De Lorenzo et al., 1997;Nana et al., 2012a), and more recently, results from Zemski et al. (2019), with a consecutive-day FM CV of 2.9% and lean mass CV of 1.1%. Despite obtaining excellent precision from utilizing a standardized presentation protocol, those authors found biological variance (consecutive day) to be higher than technical error (same day), most probably due to short-term changes in hydration (Nana et al., 2012a), sleep hygiene (Vitale et al., 2019), and intramuscular solute levels (Bone et al., 2017). These findings would support the results from this study with an FM and FFM CV of 2.4% and 0.5%, respectively. ...
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Athletic populations require high-precision body composition assessments to identify true change. Least significant change determines technical error via same-day consecutive tests but does not integrate biological variation, which is more relevant for longitudinal monitoring. The aim of this study was to assess biological variation using least significant change measures from body composition methods used on athletes, including surface anthropometry (SA), air displacement plethysmography (BOD POD), dual-energy X-ray absorptiometry (DXA), and bioelectrical impedance spectroscopy (BIS). Thirty-two athletic males (age = 31 ± 7 years; stature = 183 ± 7 cm; mass = 92 ± 10 kg) underwent three testing sessions over 2 days using four methods. Least significant change values were calculated from differences in Day 1 Test 1 versus Day 1 Test 2 (same-day precision), as well as Day 1 Test 1 versus Day 2 (consecutive-day precision). There was high agreement between same-day and consecutive-day fat mass and fat-free mass measurements for all methods. Consecutive-day precision error in comparison with the same-day precision error was 50% higher for fat mass estimates from BIS (3,607 vs. 2,331 g), 25% higher from BOD POD (1,943 vs. 1,448 g) and DXA (1,615 vs. 1,204 g), but negligible from SA (442 vs. 586 g). Consecutive-day precision error for fat-free mass was 50% higher from BIS (3,966 vs. 2,276 g) and SA (1,159 vs. 568 g) and 25% higher from BOD POD (1,894 vs. 1,450 g) and DXA (1,967 vs. 1,461 g) than the same-day precision error. Precision error in consecutive-day analysis considers both technical error and biological variation, enhancing the identification of small, yet significant changes in body composition of resistance-trained male athletes. Given that change in physique is likely to be small in this population, the use of DXA, BOD POD, or SA is recommended.
... Previous animal and human studies demonstrated that the increase in muscle glycogen following high-carbohydrate diet (i.e., carbohydrate loading) is accompanied by an increase of 2.7-4.0 g of body water per gram of glycogen (11,12,25,26). In addition, studies using magnetic resonance imaging with T2 relaxation time and bioimpedance techniques have demonstrated that the increased body water during carbohydrate loading is mainly related to the increase in intracellular water (4,22,30). These results suggest that glycogen is stored with intracellular binding water. ...
... Despite the substantial difference in thigh muscle glycogen content between the glycogen-depleted and the glycogen-recovered groups, no difference was observed in ECW and ICW distribution at the leg. In case that decrease in muscle glycogen is accompanied by the loss of 2.7-4.0 g of water per gram of glycogen as is the case in carbohydrate loading (4,25,28), loss of water in this study is estimated to be 240 -350 ml. It is comparable to 5.1-7.5% of ECW or 3.1-4.6% of ICW in the leg, from the standard muscle mass of a Japanese male adult (1), and exceeds day-to-day variability of ECW and ICW at the leg. ...
... Therefore, it can be presumed that residual macromolecules have enough water retention capacity more than make up for glycogen depletion. In contrast to this result, we and other groups have commonly reported that muscle glycogen supercompensation increases body water content, and it is probably due to increase in ICW (4,25,30). The difference in body water dynamics between muscle glycogen-supercompensated and glycogen-depleted conditions implies that change in ICW induces exclusively when intercellular glycogen content apparently exceeds normal level. ...
Article
Although each gram of glycogen is well known to bind 2.7-4.0 g of water, no studies have been conducted on the effect of muscle glycogen depletion on body water distribution. We investigated changes in extracellular and intracellular water (ECW and ICW) distribution in each body segment in muscle glycogen-depletion and glycogen-recovery condition using segmental bioimpedance spectroscopy technique (BIS). Twelve male subjects consumed 7.0 g.kg body mass-1 of indigestible (glycogen-depleted group) or digestible (glycogen-recovered group) carbohydrate for 24 hours after a glycogen-depletion cycling exercise. Muscle glycogen content using 13C-magnetic resonance spectroscopy, blood hydration status, body composition, and ECW and ICW content of the arm, trunk, and leg using BIS were measured. Muscle glycogen content at the thigh muscles decreased immediately after exercise (glycogen-depleted group, 71.6 {plus minus} 12.1 to 25.5 {plus minus} 10.1 mmol.kg-1 wet wt; glycogen-recovered group, 76.2 {plus minus} 16.4 to 28.1 {plus minus} 16.8 mmol.kg-1 wet wt) and recovered in the glycogen-recovered group (72.7 {plus minus} 21.2 mmol.kg-1 wet wt), but not in the glycogen-depleted group (33.2 {plus minus} 12.6 mmol.kg-1 wet wt) 24 hours post-exercise. Fat-free mass decreased in the glycogen-depleted group ( P < 0.05), but not in the glycogen-recovered group 24 hours post-exercise. However, no changes were observed in ECW and ICW content at the leg in both groups. Our results suggested that glycogen depletion per se does not alter body water distribution as estimated via BIS. This information is valuable in assessing body composition using BIS in athletes who show variable glycogen status during training and recovery.
... Recently, there has been an increased interest in examining the effects of acute dietary manipulations on measures of body composition utilizing dual x-ray absorptiometry (DXA) and bioelectrical impedance assessment (BIA) [8][9][10] . Glycogen and creatine are both associated with changes in hydration status and fluid retention in various body compartments 8,11,12 . ...
... Recently, there has been an increased interest in examining the effects of acute dietary manipulations on measures of body composition utilizing dual x-ray absorptiometry (DXA) and bioelectrical impedance assessment (BIA) [8][9][10] . Glycogen and creatine are both associated with changes in hydration status and fluid retention in various body compartments 8,11,12 . Using standardized carbohydrate (CHO) or creatine loading protocols it is apparent that acute dietary strategies can artificially increase estimates of lean total mass and reduce estimated fat mass 13,14 . ...
... Five days of Cr loading has previously been shown to significantly increase intramuscular Cr concentrations in young healthy adults 19 . Over the course of the five days participants consumed four doses of 5 g of creatine monohydrate (Optimum Nutrition, Aurora, Illinois) spaced out throughout the day 8,14 . Each individual dose (5g) was weighed and provided to the participant in separate bags to be mixed with 10oz of water for ingestion 13,14 . ...
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Introduction: This pilot study examined the effects of carbohydrate loading (CHO) and oral creatine monohydrate loading (Cr) on ultrasound measurements of the lower limbs. Methods: Twelve recreationally-active males (25.5 ± 6.2 y, 81.5 ± 9.6 kg, 180.9 ± 8.8 cm) completed baseline (BL) bioelectrical impedance analysis (BIA) and muscle ultrasound imaging of the rectus femoris (RF) and the vastus lateralis (VL). Following baseline measurements, participants completed one day of CHO loading (10g CHO/kg), and five days of Cr loading (20g/day). Following each treatment, participants reported to the lab after an overnight fast for BIA and ultrasound testing in which muscle thickness (MT), cross-sectional area (CSA) and echo intensity (EI) were assessed on the RF and VL. A repeated measures analyses of variance were used for each variable to assess differences between dietary conditions. Results: Significant main effects (p<0.05) were observed for RF and VL MT, RF CSA. RF MT increased from BL-Cr (p<0.00, +6.85%) and CHO-Cr (p=0.002, +4.59%). VL MT increased from BL-Cr (p=0.008, +6.46%) and CHO-Cr (p=0.006, +3.71%). RF CSA increased between CHO-Cr (p=0.034, +3.58%). No significant differences were seen for EI. Conclusions: These data show that acute dietary manipulations may influence muscular ultrasound measurements of MT and CSA.
... In 2014, we became aware of the newly launched MuscleSound ® tool and realised both its potential to enhance our work as sports nutrition practitioners and applied researchers, and the opportunity to test its reliability and validity as an additional arm within a pre-existing project investigating interactions between manipulations of muscle glycogen and creatine content [28]. Although the main aim of the study was to investigate the effect of creatine and glycogen loading on cycling performance, we embedded a research arm to investigate artefacts in the measurement of lean mass by dual energy X-ray absorptiometry due to changes in muscle water content associated with changes in muscle creatine, glycogen, and water content [29]. We invited the MuscleSound ® group to use this opportunity to further test their technology in scenarios that are very common in sports, but outside the conditions under which their own validation studies were conducted [4,5]. ...
... It is well documented that rapid creatine supplementation protocols are associated with an increase (~1 kg) in body mass that is largely attributed to a gain in body water [44][45][46]. Results from the larger study from which the Bone MuscleSound ® data were collected included a 6% increase in muscle creatine concentrations and a 22% increase in muscle glycogen when their respective loading protocols were undertaken according to best practice principles [29]. The corresponding changes in total body water and intracel-lular water, measured via BIS, were 1.3% and 1.4% (creatine loaded), and 2.3% and 2.2% (glycogen loaded), respectively [29]. ...
... Results from the larger study from which the Bone MuscleSound ® data were collected included a 6% increase in muscle creatine concentrations and a 22% increase in muscle glycogen when their respective loading protocols were undertaken according to best practice principles [29]. The corresponding changes in total body water and intracel-lular water, measured via BIS, were 1.3% and 1.4% (creatine loaded), and 2.3% and 2.2% (glycogen loaded), respectively [29]. It is possible, therefore, that changes in muscle creatine, and its associated effect on muscle water, contributed to failure of the MuscleSound ® to accurately track the changes in muscle glycogen stores. ...
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Researchers and practitioners in sports nutrition would greatly benefit from a rapid, portable, and non-invasive technique to measure muscle glycogen, both in the laboratory and field. This explains the interest in MuscleSound®, the first commercial system to use high-frequency ultrasound technology and image analysis from patented cloud-based software to estimate muscle glycogen content from the echogenicity of the ultrasound image. This technique is based largely on muscle water content, which is presumed to act as a proxy for glycogen. Despite the promise of early validation studies, newer studies from independent groups reported discrepant results, with MuscleSound® scores failing to correlate with the glycogen content of biopsy-derived mixed muscle samples or to show the expected changes in muscle glycogen associated with various diet and exercise strategies. The explanation of issues related to the site of assessment do not account for these discrepancies, and there are substantial problems with the premise that the ratio of glycogen to water in the muscle is constant. Although further studies investigating this technique are warranted, current evidence that MuscleSound® technology can provide valid and actionable information around muscle glycogen stores is at best equivocal.
... However, the resultant muscle glycogen levels after glycogen loading is highly variable [31], perhaps due to the complexity underlying intramuscular glycogen storage [25]. Similarly, while it is clear that glycogen loading can increase intracellular water content [31], muscle thickness [15], and lean body mass (LBM) estimates [32], the relative extent of intracellular hydration in grams of water per gram of glycogen may vary so greatly that it is not statistically correlated with glycogen content [30]. ...
... Creatine supplementation has also been shown to aid in glycogen synthesis and supercompensation [132]. Additionally, consuming CHO with creatine increases creatine loading [133], which increases cellular hydration as noted above [32,129]. Finally, muscle creatine levels decline very slowly after loading [134], so creatine intake after peak week glycogen loading is not needed except perhaps in small amounts to potentially accelerate last minute, competition day carbohydrate delivery into skeletal muscle. ...
... Creatine supplementation has been shown to aid in glycogen synthesis and supercompensation [132]. Additionally, consuming CHO with creatine increases creatine loading [133], which increases intracellular hydration [32,129]. In conjunction with creatine, carbohydrate powders (e.g. ...
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Bodybuilding is a competitive endeavor where a combination of muscle size, symmetry, “conditioning” (low body fat levels), and stage presentation are judged. Success in bodybuilding requires that competitors achieve their peak physique during the day of competition. To this end, competitors have been reported to employ various peaking interventions during the final days leading to competition. Commonly reported peaking strategies include altering exercise and nutritional regimens, including manipulation of macronutrient, water, and electrolyte intake, as well as consumption of various dietary supplements. The primary goals for these interventions are to maximize muscle glycogen content, minimize subcutaneous water, and reduce the risk abdominal bloating to bring about a more aesthetically pleasing physique. Unfortunately, there is a dearth of evidence to support the commonly reported practices employed by bodybuilders during peak week. Hence, the purpose of this article is to critically review the current literature as to the scientific support for pre-contest peaking protocols most commonly employed by bodybuilders and provide evidence-based recommendations as safe and effective strategies on the topic.
... The second phase consisted of a carbohydrate load coupled with an increase in water and dietary salt. After depleting skeletal muscle glycogen, previous evidence suggests that a supercompensation effect is achievable where the muscle can store greater amounts of glycogen [36,37], thus, leading to greater intracellular fluid [14], muscle thickness [5,11], and lean body mass estimates [37]. From three days out to one day out, carbohydrate intake was increased to 7.9 g/kg per day, water was increased by~49% to~116 mL/kg, and sodium intake via added salt was increased by~33%. ...
... The second phase consisted of a carbohydrate load coupled with an increase in water and dietary salt. After depleting skeletal muscle glycogen, previous evidence suggests that a supercompensation effect is achievable where the muscle can store greater amounts of glycogen [36,37], thus, leading to greater intracellular fluid [14], muscle thickness [5,11], and lean body mass estimates [37]. From three days out to one day out, carbohydrate intake was increased to 7.9 g/kg per day, water was increased by~49% to~116 mL/kg, and sodium intake via added salt was increased by~33%. ...
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Background: The purpose of this case study was to implement an evidence-based dietary approach to peaking for a bodybuilding competition and monitor its impact on body composition, muscle thickness (MT), intra-to-extra-cellular fluid shifts, subcutaneous thickness (ST), and hydration status. Secondarily, to document any adverse events of this peak week approach in a small, controlled setting. Methods Dietary practices were recorded, and laboratory testing was conducted throughout peak week, including competition morning. Assessments included: dual-energy X-ray absorptiometry (DEXA) for body composition, B-mode ultrasound for MT and ST, bioimpedance spectroscopy (BIS) for total body water (TBW)/intracellular water (ICW)/extracellular water (ECW), and raw BIS data (i.e., resistance, reactance, and phase angle), urine specific gravity (USG) for hydration status, and subjective fullness. Sequential dietary manipulations were made (i.e., CHO depletion/fat loading, CHO/water loading, and a refinement phase) with specific physiological goals. This was reflected in changes observed across all assessments throughout the peak week. Results: From the carbohydrate-depleted state (three days out) to competition day, we observed increases in lean body mass, MT, TBW (primarily ICW), and subjective fullness. Kendall's Tau B revealed a strong relationship between carbohydrate intake and ∑MT (τ = 0.733, p = 0.056). Additionally, novel ST data demonstrated a 10% reduction for the summation of all seven sites, with some drastic changes in specific regions (e.g., -43% for triceps ST) from three days out to competition day. Conclusions: These data suggest that the prototypical goals of bodybuilders' peak week (i.e., increasing muscle fullness, decreasing subcutaneous thickness) to enhance their aesthetics/muscularity presented can be achieved with a drug-free protocol involving dietary manipulations.
... Furthermore, although one case study reported that body composition assessments were conducted in the fasted state (40), the others either did not report standardization procedures or used suboptimal standardization procedures before assessment (e.g., a 4-hour fast as opposed to overnight) (19,39). Multiple research groups have recently demonstrated the importance of adequate preassessment controls before body composition evaluation (4,53), and these control measures may be especially critical in case studies, which derive all information from a single subject. ...
... A recent investigation indicated that multifrequency impedance techniques may be able to detect increases in ICW in response to carbohydrate loading (46), and we observed an increase in ICW that exceeded the MD when comparing values from 3 days before 5 days after each competition. This is in agreement with previous reports that acute bolstering of muscular glycogen content can increase TBW and FFM estimates (4,53). Furthermore, the increase in reported energy intake and measured RQ after competition supports the contention that the increased FFM immediately after contest could have been due to carbohydrate stores and water. ...
Article
Tinsley, GM, Trexler, ET, Smith-Ryan, AE, Paoli, A, Graybeal, AJ, Campbell, BI, and Schoenfeld, BJ. Changes in body composition and neuromuscular performance through preparation, two competitions, and a recovery period in an experienced female physique athlete. J Strength Cond Res XX(X): 000-000, 2018-This prospective case study evaluated an experienced female figure competitor during contest preparation, 2 competitions, and a recovery period. Twelve laboratory sessions were conducted over 8 months. At each visit, body composition was assessed by 4-compartment model, resting metabolic rate (RMR) by indirect calorimetry, and neuromuscular performance by peak force and rate of force development (RFD) on a mechanized squat device. Caloric intake ranged from 965 to 1,610 kcal·d (16.1-24.8 kcal·kg·BM; 18.2-31.1 kcal·kg·FFM), with varying macronutrient intakes (CHO: 0.3-4.8 g·kg; PRO: 1.7-3.0 g·kg; and FAT: 0.2-0.5 g·kg). Body fat was reduced from 20.3 to 12.2% before the first competition and declined to 11.6% before the second competition. Fat-free mass increased by 2.1% before the first competition and peaked at 4.6% above baseline in the recovery period. Resting metabolic rate decreased from 1,345 kcal·d at baseline to a low value of 1,119 kcal·d between competitions. By the end of recovery, RMR increased to 1,435 kcal·d. Concentric and eccentric peak forces declined by up to 19% before the first competition, experienced perturbations in the inter-competition and recovery periods, and remained 5-8% below baseline at study termination. Similarly, RFD decreased by up to 57% before the first competition, was partially recovered, but remained 39% lower than baseline at study termination. Despite favorable body composition changes, neuromuscular performance was impaired during and after the competitive season in an experienced female physique competitor.
... LSC quantifies precision based on 2 consecutive scans, thus identifying the technical error inbuilt into a specific piece of equipment for a given population (7). However, in practice, longitudinal measures are taken weeks or months apart, and despite following recommended best practice protocols (9), some level of day-to-day biological variation will be present in variables such as hydration status and muscle solute content, both of which impact results (10,11). It is unclear what influence these factors have on body composition LSC calculations. ...
... The regressions between measures of bone mineral content for same-day (top; R 2 = 1.00) and consecutive-day (bottom; R 2 = 0.99) precision. relevant in resistance-trained individuals who have the potential for larger fluctuations in hydration status and intramuscular solutes such as creatine and glycogen over a short time frame (11,23). Our consecutive-day testing resulted in wider precision errors for FM (CV: 1.8% vs 2.9%, LSC: 5.1% vs 8.0%) and LM (CV: 0.3% vs 1.1%, LSC: 0.9% vs 3.2%), indicating small amounts of biological variation despite use of best practice protocols (9), and instructions to the participants to eat normally and not exercise between consecutive-day scans. ...
Article
The application of dual-energy X-ray absorptiometry (DXA) in sport science settings is gaining popularity due to its ability to assess body composition. The International Society for Clinical Densitometry (ISCD) recommends application of the least significant change (LSC) to interpret meaningful and true change. This is calculated from same-day consecutive scans, thus accounting for technical error. However, this approach does not capture biological variation, which is pertinent when interpreting longitudinal measurements, and could be captured from consecutive-day scans. The aims of this study were to investigate the impact short-term biological variation has on LSC measures, and establish if there is a difference in precision based on gender in a resistance-trained population. Twenty-one resistance-trained athletes (age: 30.6 ± 8.2 yr; stature: 174.2 ± 7.2 cm; mass: 74.3 ± 11.6 kg) with at least 12 mo consistent resistance training experience, underwent 2 consecutive DXA scans on 1 d of testing, and a third scan the day before or after. ISCD-recommended techniques were used to calculate same-day and consecutive-day precision error and LSC values. There was high association between whole body (R² = 0.98–1.00) and regional measures (R² = 0.95–0.99) for same-day (R² = 0.98–1.00), and consecutive-day (R² = 0.95–0.98) measurements. The consecutive-day precision error, in comparison to same-day precision error, was significantly different (p < 0.05), and almost twice as large for fat mass (1261 g vs 660 g), and over 3 times as large for lean mass (2083 g vs 617 g), yet still remained within the ISCD minimum acceptable limits for DXA precision error. No whole body differences in precision error were observed based on gender. When tracking changes in body composition, the use of precision error and LSC values calculated from consecutive-day analysis is advocated, given this takes into account both technical error and biological variation, thus providing a more accurate indication of true and meaningful change.
... The DXA measurements used for subsequent calculations were carried out in one center in the morning, 2 hr after a standardized 350-kcal breakfast, 1 day before the start, and within 7-10 days after the completion of the protocol. This time period was chosen to avoid misinterpretation due to acute changes in tissue glycogen and hydration resulting from the protocol (Bone et al., 2017). ...
... Our study, leading to a substantial reduction of fat mass with only a small reduction in lean mass thus achieves similar results on a shorter term, despite differences in the nutritional intervention and exercise setting. During DXA measurement, correct positioning of the subjects was double-checked, and errors due to dehydration and incomplete glycogen repletion (Bone et al., 2017) were avoided by measuring body weight and composition within 7-10 days after the intervention. Although short-term repeat DXA scans showed low coefficients of variation and good reproducibility for whole body mass, lean mass, and fat mass (Moreira et al., 2018), small precision errors known to occur in relation to obesity (Knapp et al., 2015) may have been encountered in a percentage (15%) of participants with BMIs of over 30 kg/m 2 . ...
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Adaptation, and Nutrition (EULEAN) Fasting enhances the beneficial metabolic outcomes of exercise; however, it is unknown whether body composition is favorably modified on the short term. A baseline-follow-up study was carried out to assess the effect of an established protocol involving short-term combined exercise with fasting on body composition. One hundred seven recreationally exercising males underwent a 10-day intervention across 15 fitness centers in the Netherlands involving a 3-day gradual decrease of food intake, a 3-day period with extremely low caloric intake, and a gradual 4-day increase to initial caloric intake, with daily 30-min submaximal cycling. Using dual-energy X-ray absorptiometry analysis, all subjects substantially lost total body mass (−3.9 ± 1.9 kg; p < .001) and fat mass (−3.3 ± 1.3 kg; p < .001). Average lean mass was lost (−0.6 ± 1.5 kg; p < .001), but lean mass as a percentage of total body mass was not reduced. The authors observed a loss of −3.9 ± 1.9% android fat over total fat mass (p < .001), a loss of −2.2 ± 1.9% gynoid over total fat mass (p < .001), and reduced android/gynoid ratios (−0.05 ± 0.1; p < .001). Analyzing 15 preselected single-nucleotide polymorphisms in 13 metabolism-related genes revealed trending associations for thyroid state-related single-nucleotide polymorphisms rs225014 (deiodinase 2) and rs35767 (insulin-like growth factor1), and rs1053049 (PPARD). delli Paoli, van de Laarschot, Zillikens, and de Lange contributed equally to the work. delli Paoli, Senese, Lanni, and de Lange are with the
... A limitation of the study was that dietary intake and water balance (and thus energy balance) were not measured on the day prior to RMR measurement (Toomey, McCormack, & Jakeman, 2017). Fuel or glycogen fluctuations may impact body composition assessment ( Bone et al., 2017). Athletes were sched- uled after non or low-training days; and within this study a minimum of 10 hours, but typically 12-14 hours after training was allocated for the RMR measurement in line with evidence of 2 hours of abstention from moderate aerobic exercise (Grade II -fair) and 14 hours for vigorous exercise (Grade III -limited) as advised for non-athletes (Compher et al., 2006) though there is conjecture on the time frame required for RMR to normalise after different training types. ...
... Notably, training may substantially influence RMR in trained individuals and trained individuals' RMR returns more rapidly to baseline after physical activity (Short & Sedlock, 1997). While creatine monohydrate supplementation may have a trivial impact on body composition assessment in similar populations ( Bone et al., 2017), in this study it was not supported and/or prescribed by the athletes' programme. In addition, participants could listen to quiet music to alleviate boredom. ...
Article
Optimising dietary energy intake is essential for effective sports nutrition practice in rugby athletes. Effective dietary energy prescription requires careful consideration of athletes’ daily energy expenditure with the accurate prediction of resting metabolic rate (RMR) important due to its influence on total energy expenditure and in turn, energy balance. This study aimed to (a) measure rugby athletes RMR and (b) report the change in RMR in developing elite rugby players over a rugby preseason subsequent to changes in body composition and (c) explore the accurate prediction of RMR in rugby athletes. Eighteen developing elite rugby union athletes (age 20.2 ± 1.7 years, body mass 101.2 ± 14.5 kg, stature 184.0 ± 8.4 cm) had RMR (indirect calorimetry) and body composition (dual energy x-ray absorptiometry) measured at the start and end of a rugby preseason ∼14 weeks later. There was no statistically significant difference in RMR over the preseason period (baseline 2389 ± 263 kcal·day⁻¹ post 2373 ± 270 kcal·day⁻¹) despite a significant increase in lean mass of +2.0 ± 1.6 kg (P < 0.01) and non-significant loss of fat mass. The change in RMR was non-significant and non-meaningful; thus, this study contradicts the commonly held anecdotal perception that an increase in skeletal muscle mass will result in a significant increase in metabolic rate and daily energy needs. Conventional prediction equations generally under-estimated rugby athletes’ measured RMR, and may be problematic for identifying low energy availability, and thus updated population-specific prediction equations may be warranted to inform practice.
... Nonetheless, the physical maturity of young jockeys can differ significantly between study cohorts, and lower LMI values emphasise this in apprentice (15.3 kg m −2 ) and conditional (16.4 kg m −2 ) jockeys [13]. Furthermore, DXA assessment of LM in jockeys requires careful pre-scan presentation as results are affected by acute changes in hydration and glycogen status [40,51]. Thus, where strict measurement protocols are impractical caution is advised when interpreting results as lifestyle factors frequently experienced by jockeys such as rapid weight loss using food and fluid restriction could increase the variability of accurate LM results [40,51]. ...
... Furthermore, DXA assessment of LM in jockeys requires careful pre-scan presentation as results are affected by acute changes in hydration and glycogen status [40,51]. Thus, where strict measurement protocols are impractical caution is advised when interpreting results as lifestyle factors frequently experienced by jockeys such as rapid weight loss using food and fluid restriction could increase the variability of accurate LM results [40,51]. ...
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Jockeys are unlike other weight-making athletes as the sport of horse racing requires strict weight management to meet the racing stipulations, protracted working hours and an extended racing season with limited downtime. Several studies have reported on the body composition and bone status of male and female professional and retired jockeys, yet the variety of assessment techniques, lack of standardised testing protocols and classification inconsistency make interpretation and comparison between studies problematic. This review aimed to appraise the existing body composition and bone health evidence in jockeys and evaluate the assessment methods and classification criteria used. Dual-energy X-ray absorptiometry (DXA) has been used most frequently in jockey research to assess body composition and bone status, while various generic skinfold equations have been used to predict body fat percentage. Evidence indicates flat jockeys are now taller and heavier than the data reported in earlier studies. Absolute fat mass has steadily increased in male jockeys in the last decade. The bone status of male jockeys remains a concern as constant low bone density (BMD) is evident in a large percentage of young and experienced professional jockeys. Due to limited studies and variations in assessment methods, further research is required to investigate bone turnover markers in male and female jockeys. A standardised testing protocol using internationally recognised assessment guidelines is critical for the accurate interpretation and evaluation of body composition and bone health measurements. Furthermore, establishing jockey-specific BMD and bone turnover reference ranges should be considered using existing and future data.
... Laboratory based TEM and CV for this system is 42 kcal·day -1 and <2%, respectively. Application of measurement and subsequent analyses were conducted according to the recommendations of Bone and colleagues (18) and predicted RMR (RMR pred ) was calculated via the Cunningham equation (19). RMR ratio was established by the division of RMR meas and RMR pred , where a values of <0.90 were classified to define instances of potential energy deficiency (20). ...
Article
Purpose: To evaluate the effects of low energy availability (EA) on health and performance indices associated with the Male Athlete Triad and Relative Energy Deficiency in Sports (RED-S) models. Methods: Over an 8 week period, a male combat sport athlete adhered to a phased body mass (BM) loss plan consisting of 7 weeks energy intake (EI) equating to resting metabolic rate (RMR) (1700 kcal·day) (Phase 1), 5 days of reduced EI (1200-300 kcal·day) prior to weigh-in (Phase 2) and one week of ad libitum EI post-competition (Phase 3). EA fluctuated day by day due to variations in exercise energy expenditure. Regular assessments of body composition, RMR, cardiac function, cardiorespiratory capacity, strength & power, psychological state and blood clinical chemistry for endocrine, bone turnover, hydration, electrolyte, renal, liver and lipid profiles were performed. Results: BM was reduced over the 8 week period by 13.5% (72.5 to 62.7 kg). No consequences of Male Athlete Triad or RED-S were evident during phase 1, where mean daily EA equated to 20 kcal·kg·FFM·day (range: 7 to 31 kcal·kg·FFM·day) and BM and fat mass (FM) losses were 6.5 and 4.4 kg, respectively. However, consequences did present in phase 2 when mean daily EA was consistently <10 kcal·kg·FFM·day, as evidenced by alterations to endocrine hormones (e.g. testosterone: <5 nmol.L) and reduced RMR (-257 kcal·day). Conclusion: Data demonstrate that 7 weeks of daily fluctuations in EA equating to a mean value of 20 kcal·kg·FFM·day permits reductions of BM and FM without perturbations to physiological systems associated with the Male Athlete Triad and RED-S. In contrast, a subsequent period of 5 consecutive days of EA <10 kcal·kg·FFM·day induced consequences of Male Athlete Triad and RED-S.
... Assuming a 1:3 molar ratio of glycogen: water (wt/vol) the authors suggested the initial reduction could account for ~0.37 kg of body mass. This estimate is markedly lower than the ~1.6-2.0 kg losses from a 4-day verylow carbohydrate diet (Kreitzman et al., 1992) and evidence that glycogen loading from a depleted state increases body mass by ~3.4% (Bone et al., 2017). The latter changes may reflect the changes in MMA, where athletes typically utilise a low-carbohydrate diet during RWL and have high-carbohydrate intakes during RWG (Coswig et al., 2018;Matthews & Nicholas, 2017). ...
Article
Combat sport athletes typically engage in a process called making-weight, characterised by rapid weight loss (RWL) and subsequent rapid weight gain (RWG) in the days preceding competition. These practices differ across each sport, but no systematic comparison of the size of the changes in body mass exists. The aim was to determine the magnitude of RWL and RWG in combat sport athletes preparing for competition. The review protocol was preregistered with PROSPERO [CRD42017055279]. In eligible studies, athletes prepared habitually with a RWL period ≤7 days preceding competition. An electronic search of EBSCOhost (CINAHL Plus, MEDLINE, SPORTDiscus) and PubMed Central was performed to July 2018. Sixteen full-text studies (total 4432 participants, 156 female, 4276 male) were included, providing data from five combat sports (boxing, judo, mixed martial arts (MMA), taekwondo and wrestling). Three studies reported RWL and fourteen studies reported RWG. Duration permitted for RWG ranged 3-32 hours. The largest changes in body mass occurred in two separate MMA cohorts (RWL 7.4 ± 1.1kg [~10%], RWG 7.4 ± 2.8kg [11.7 ± 4.7%]). The magnitude of RWG appears to be influenced by the type of sport, competition structure, and recovery duration permitted. A cause for concern is the lack of objective data quantifying the magnitude of RWL. There is insufficient evidence to substantiate the use of RWG as a proxy for RWL, and little data are available in females. By engaging in RWG, athletes are able to exploit rules to compete up to three weight categories higher than at the official weigh-in.
... Examples of methods based on the 2C model include hydrodensitometry (underwater weighing), air displacement plethysmography (ADP or BOD POD®), skinfold thickness, and bioelectrical impedance analysis (BIA). Dual energy X-ray absorptiometry (DXA) is based on a 3C model that measures bone mineral content, LM, and FM, but it is still subject to confounding from inter-assessment differences in hydration, glycogen, and muscle creatine levels, which can be significant in athletic populations with distinct exercise and recovery cycles [7,8]. ...
Article
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Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of diet types (macronutrient composition; eating styles) and their influence on body composition. The ISSN has concluded the following. 1) There is a multitude of diet types and eating styles, whereby numerous subtypes fall under each major dietary archetype. 2) All body composition assessment methods have strengths and limitations. 3) Diets primarily focused on fat loss are driven by a sustained caloric deficit. The higher the baseline body fat level, the more aggressively the caloric deficit may be imposed. Slower rates of weight loss can better preserve lean mass (LM) in leaner subjects. 4) Diets focused primarily on accruing LM are driven by a sustained caloric surplus to facilitate anabolic processes and support increasing resistance-training demands. The composition and magnitude of the surplus, as well as training status of the subjects can influence the nature of the gains. 5) A wide range of dietary approaches (low-fat to low-carbohydrate/ketogenic, and all points between) can be similarly effective for improving body composition. 6) Increasing dietary protein to levels significantly beyond current recommendations for athletic populations may result in improved body composition. Higher protein intakes (2.3–3.1 g/kg FFM) may be required to maximize muscle retention in lean, resistance-trained subjects under hypocaloric conditions. Emerging research on very high protein intakes (>3 g/kg) has demonstrated that the known thermic, satiating, and LM-preserving effects of dietary protein might be amplified in resistance-training subjects. 7) The collective body of intermittent caloric restriction research demonstrates no significant advantage over daily caloric restriction for improving body composition. 8) The long-term success of a diet depends upon compliance and suppression or circumvention of mitigating factors such as adaptive thermogenesis. 9) There is a paucity of research on women and older populations, as well as a wide range of untapped permutations of feeding frequency and macronutrient distribution at various energetic balances combined with training. Behavioral and lifestyle modification strategies are still poorly researched areas of weight management.
... Several recent studies have highlighted the potential impact of acute dietary alterations on body composition estimates produced by DXA [5,6]. However, there have been no examinations of the impact of pre-assessment dietary composition on estimates of VAT produced by DXA. ...
Article
Dual-energy x-ray absorptiometry (DXA) is viewed as a superior method of body composition assessment, but whole-body DXA scans are impacted by variation in pre-assessment activities, such as eating and drinking. DXA software now allows for estimation of visceral adipose tissue (VAT), which has been implicated in a number of diseases. It is unknown to what extent food and fluid intake affect VAT estimates. Purpose: To determine the effects of acute high-carbohydrate (HC) and very low-carbohydrate (VLC) diets on DXA estimates of VAT. Methods: Male and female adults completed two one-day dietary conditions in random order: a VLC diet (1 – 1.5 g CHO/kg) and a HC diet (9 g CHO/kg). The diets were isocaloric to each other, and all food items were provided to participants. DXA scans were conducted in the morning after an overnight fast and in the afternoon soon after the third standardized meal. VAT volume, mass, and area were obtained, and paired samples t-tests were performed to compare the changes in VAT measures between diets. Results: Fifteen males (age 22 ± 3, BF% 21 ± 5%) and eighteen females (age 21 ± 2, BF% 31 ± 5%) were included in the analysis. The change in VAT volume between the fasted and fed visits was different between diets (HC: +1.6%; VLC: -9.2%, p= 0.047). There were also trends for differences in VAT mass (p= 0.089) and area (p= 0.096) changes between diets. Conclusions: Within a single day, VAT estimates are differentially affected by isocaloric HC and VLC diets, with VLC consumption leading to reductions in VAT estimates. The content of the diet on the day of a DXA scan can affect estimates of VAT, which could spuriously influence the categorization of an individual’s health risk by DXA VAT estimates. Standardization of food intake prior to scans, preferably in the form of an overnight fast, should be employed to eliminate this important source of error.
... Accordingly, this technique is not suitable for pregnant women and, although safe, is not always accepted by parents for use in young children. A study in male cyclists showed that changes in muscle concentrations of glycogen and/or creatine resulted in erroneous readings of increased lean body mass by DXA as muscle hydration was altered [29]. ...
Purpose of review: The current article reviews the most innovative and precise, available methods for quantification of in-vivo human body composition. Recent findings: Body composition measurement methods are continuously being perfected. Ongoing efforts involve multisegmental and multifrequency bioelectrical impedance analysis, quantitative magnetic resonance for total body water, fat, and lean tissue measurements, imaging to further define ectopic fat depots. Available techniques allow for the measurement of fat, fat-free mass, bone mineral content, total body water, extracellular water, total adipose tissue and its subdepots (visceral, subcutaneous, and intermuscular), skeletal muscle, select organs, and ectopic fat depots. Summary: There is an ongoing need for methods that yield information on metabolic and biological functions. Based on the wide range of measurable properties, analytical methods and known body composition models, clinicians, and scientists can quantify a number of body components and with longitudinal assessment, can track changes in health and disease with implications for understanding efficacy of nutritional and clinical interventions, diagnosis, prevention, and treatment in clinical settings. With the greater need to understand precursors of health risk beginning prior to conception, a gap exists in appropriate in-vivo measurement methods with application beginning during gestation, that is, fetal development.
... While performing body composition assessment after an overnight fast is a valid recommendation, a need for increased standardization of pre-assessment activities has recently been advocated (Hangartner, Warner, Braillon, Jankowski, & Shepherd, 2013). In support of this recommendation, recent evidence has indicated that, even after an overnight fast, the pre-assessment diet may impact DXA body composition estimates (Bone et al., 2017). In particular, the carbohydrate content of the diet may be an influencing factor, with the lean soft tissue compartment most affected (Tinsley, Morales, Forsse, & Grandjean, 2017). ...
Article
Two research groups recently produced equations for estimation of body volume from dual-energy x-ray absorptiometry (DXA) scans. These body volume estimates can be used for body composition evaluation in modified 4-compartment models. In the present analysis, the reliability of body volume calculations, as well as their usage in 4-compartment models, was explored while employing precise scheduling of assessments and dietary standardization. Forty-eight recreationally active males and females completed two pairs of identical assessments, which included a DXA scan and single-frequency bioelectrical impedance analysis. Each assessment within a pair was separated by 24 hours, during which participants were provided a standardized diet. Body volume and 4-compartment equations were applied to the data, and metrics of reliability and agreement were calculated for body volume and 4-compartment components. While both body volume equations demonstrated excellent reliability individually, substantial disagreement between equations was present when utilized in 4-compartment equations. The magnitude of this disagreement was 4.3 kg for lean mass and fat mass and 6.9% for body fat percentage. At present, the large discrepancies in body composition components when using existing body volume equations preclude their interchangeability and demonstrate the need for continued exploration of the utility of body volume estimates.
... Compared to anthropometry, DXA is more expensive, requires bulky equipment, takes longer time to do, and requires more trained personnel. DXA estimates of muscle mass are sensitive to acute changes in muscle water content, such as seen with changes in muscle glycogen or creatinine due to feeding or dehydration[46]. A strength of the present study is that participants were recruited at three separate hospitals. ...
Article
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Background Sarcopenia is prevalent in older persons and is a risk factor for falls, fractures, and mortality. The aim of this study was to determine a) the feasibility of determining sarcopenia in patients with acute hip fracture, b) the prevalence of sarcopenia and c) associations of sarcopenia with nutritional status and comorbidities. Methods A multicenter cross-sectional study on sarcopenia in male and female patients with acute hip fracture. Participants were previously ambulatory and living in the community. Sarcopenia was assessed postoperatively with muscle mass estimated by anthropometry using triceps skinfold, arm circumference, height, weight and sex. Grip strength was measured by Jamar dynamometer and pre-fracture mobility was by self-report using the New Mobility Score. Results Out of 282 patients, 202 were assessed for sarcopenia of whom 74 (37%) were diagnosed as sarcopenic. Sarcopenia was associated with age, odds ratio (OR) 1.4 per 5 years, 95% confidence interval (CI) [1.1, 1.8], ASA Physical Status Classification System score, OR 2.3 per point, 95% CI [1.3, 4.3] and number of medications at discharge, OR 1.2 per medication, 95% CI [1.0, 1.3] and inversely associated with BMI, OR 0.8, 95% CI [0.7, 0.9] and serum albumin, OR 0.9, 95% CI [0.8,1.0]. Conclusions Thirty-seven percent of assessed subjects were diagnosed with sarcopenia. Our data demonstrates that the prevalence of sarcopenia is associated with older age, malnutrition and comorbidities. Determining sarcopenia at the bedside was feasible in postoperative hip fracture patients by using grip strength, estimation of muscle mass by anthropometry and self-reported mobility.
... Determining whether body mass loss is derived from decrease in fat mass, glycogen mass, or retained fluid is difficult. Dual x-ray absorptiometry estimation of lean body mass is greatly skewed by hydration status (23) and carbohydrate intake (24). Body composition assessment from BIA (used by Zajac et al. (7), Klement et al. (22) and the current study) is even further distorted as outcomes are determined by water-dependent electrical current conduction resistance. ...
Article
Purpose: This study examined the effects of a 3-week ad libitum high fat (~70% of calories), low carbohydrate (<50 g/day) diet (LCHF) on markers of endurance performance in middle-aged, recreationally competitive male runners. Methods: All subjects (n = 8) following their normal HC diet had anthropometric measures assessed and completed 5, 10-min running bouts at multiple individual race paces in the heat while physiological, metabolic variables and perceptual responses were recorded. After 20-min of rest, participants completed a 5-km time trial (5TT) on a road course. Subjects then consumed a LCHF diet for 3 weeks and returned for repeat testing. Results: Body mass and 7-site skinfold thickness sum decreased by approximately 2.5 kg (p < 0.01) and 13 mm (p < 0.05) after LCHF. Rectal temperature was higher after the first 10-min of exercise (37.7 ± 0.3 °C vs. 37.3 ± 0.2 °C) in the HC diet but did not differ at any other time with LCHF. Heart rate and perceptual measures did not display any consistent differences between treatments excluding thirst sensation for LCHF. Respiratory exchange ratio and carbohydrate oxidation declined significantly while fat oxidation increased after LCHF for every pace (p < 0.01). There was no significant difference (p = 0.25) in 5TT performance, but LCHF (23.45 ± 2.25 min) displayed a trend of improved performance versus HC (23.92 ± 2.57 min). Conclusion: Improved body composition and fat oxidation from LCHF potentially negate expected performance decrement from reduced carbohydrate utilization late in exercise for non-elite runners. An acute decrease in training capacity is expected; however, if performance improvement is not exhibited after 3 weeks, diet cessation is suggested for negative responders.
... Several recent studies have highlighted the potential impact of acute dietary alterations on body composition estimates produced by DXA [5,6]. However, there have been no examinations of the impact of pre-assessment dietary composition on estimates of VAT produced by DXA. ...
Article
Full-text available
We examined the reproducibility of dual-energy x-ray absorptiometry (DXA) visceral adipose tissue (VAT) estimates as well as the impact of pre-assessment diet. In a counterbalanced design, 41 adults received 6 DXA scans, while consuming standardized high- and low-carbohydrate (LC) diets. The impact of pre-assessment diet was examined via repeated-measures analysis of variance and reproducibility of VAT estimates was evaluated by technical error of measurement (TEM) and s.e. of a single determination (SESD). VAT area, mass and volume were acutely decreased by ~ 6.5% after the LC diet (P ≤ 0.001), but not the high-carbohydrate diet (P > 0.3). Differences persisted after an overnight fast. TEMs for VAT area, mass and volume were < 5 cm2, ≤ 0.2 kg and < 25 cm3. SESDs for all VAT variables were ≤ 5.5%. In conclusion, DXA VAT estimates exhibit good reproducibility in controlled conditions, but may be impacted by pre-assessment diet.
... Pre-scan preparation should also be consistent, with athletes presenting in a rested (and thus presumably glycogen replete), overnight fasted state and voiding the bladder prior to scanning in minimal clothing [64]. Detailed guidance on prior training and diet should also be provided to facilitate athletes presenting in a glycogen replete, euhydrated state, and consideration should also be given to understanding supplement use such as with creatine monohydrate [65]. ...
Article
Dual energy X-ray absorptiometry (DXA) is a medical imaging device which has become the method of choice for the measurement of body composition in athletes. The objectives of this review were to evaluate published longitudinal DXA body composition studies in athletic populations for interpretation of 'meaningful' change, and to propose a best practice measurement protocol. An online search of PubMed and CINAHL via EBSCO Host and Web of Science enabled the identification of studies published until November 2016. Those which met the inclusion criteria were reviewed independently by two authors according to their methodological quality and interpretation of body composition change. Twenty-five studies published between 1996 and November 2016 were reviewed (male athletes: 13, female athletes: 3, mixed: 9) and sample sizes ranged from n = 1 to 212. The same number of eligible studies were published between 2013 - 2016, as over the 16 years prior (1996 - 2012). Seven did not include precision error, and fewer than half provided athlete-specific precision error. There were shortfalls in the sample sizes on which precision estimates were based and inconsistencies in the level of pre-scan standardisation, with some reporting full standardisation protocols and others reporting only single (e.g. overnight fast) or no control measures. There is a need for standardised practice and reporting in athletic populations for the longitudinal measurement of body composition using DXA. Based on this review and that of others, plus the official position of the International Society for Clinical Densitometry, our recommendations and protocol are proposed as a guide to support best practice.
... Technical factors such as discrepancies in machine software/hardware (Toombs et al. 2012), subject positioning (Nana et al. 2012) or technician expertise (Hume and Marfell-Jones 2008) affect precision, whereas biological factors influenced by subject presentation play an important role (Bunt et al. 1989;Dixon et al. 2009;Kerr et al. 2017;Nana et al. 2012). Exercise, plus food and fluid intake prior to assessment Heiss et al. 2009;Dixon et al. 2009;Gallagher et al. 1998;Rouillier et al. 2015), core body temperature fluctuations (Fields et al. 2004) as well as muscle creatine and glycogen changes (Bone et al. 2016) are known to impact results. Arriving for assessment without controlling for these variables is referred to as non-standardised presentation. ...
Article
Full-text available
Purpose: High precision body composition assessment methods accurately monitor physique traits in athletes. The acute impact of subject presentation (ad libitum food and fluid intake plus physical activity) on body composition estimation using field and laboratory methods has been quantified, but the impact on interpretation of longitudinal change is unknown. This study evaluated the impact of athlete presentation (standardised versus non-standardised) on interpretation of change in physique traits over time. Thirty athletic males (31.2 ± 7.5 years; 182.2 ± 6.5 cm; 91.7 ± 10.3 kg; 27.6 ± 2.6 kg/m2) underwent two testing sessions on 1 day including surface anthropometry, dual-energy X-ray absorptiometry (DXA), bioelectrical impedance spectroscopy (BIS) and air displacement plethysmography (via the BOD POD), with combinations of these used to establish three-compartment (3C) and four-compartment (4C) models. Methods: Tests were conducted after an overnight fast (BASEam) and ~ 7 h later after ad libitum food/fluid and physical activity (BASEpm). This procedure was repeated 6 months later (POSTam and POSTpm). Magnitude of changes in the mean was assessed by standardisation. Results: After 6 months of self-selected training and diet, standardised presentation testing (BASEam to POSTam) identified trivial changes from the smallest worthwhile effect (SWE) in fat-free mass (FFM) and fat mass (FM) for all methods except for BIS (FM) where there was a large change (7.2%) from the SWE. Non-standardised follow-up testing (BASEam to POSTpm) showed trivial changes from the SWE except for small changes in FFM (BOD POD) of 1.1%, and in FM (3C and 4C models) of 6.4 and 3.5%. Large changes from the SWE were found in FFM (BIS, 3C and 4C models) of 2.2, 1.8 and 1.8% and in FM (BIS) of 6.4%. Non-standardised presentation testing (BASEpm to POSTpm) identified trivial changes from the SWE in FFM except for BIS which was small (1.1%). A moderate change from the SWE was found for BOD POD (3.3%) and large for BIS (9.4%) in FM estimations. Conclusions: Changes in body composition utilising non-standardised presentation were more substantial and often in the opposite direction to those identified using standardised presentation, causing misinterpretation of change in physique traits. Standardised presentation prior to body composition assessment for athletic populations should be advocated to enhance interpretation of true change.
... Additionally, the participants' diets were controlled and sufficient energy and protein intake were assured. No differences regarding dietary intake were detected, which is in our view important, since a glycogen increase from a higher carbohydrate intake might have confounded the body composition results (Bone et al., 2017;Rouillier, David-Riel, Brazeau, St-Pierre, & Karelis, 2015). We accounted for variation in TBW throughout the intervention, with no significant changes being detected. ...
... Recently, there has been increased awareness that, although DXA is useful for body composition assessment, it is not impervious to biological error induced by variation in subject presentation. Acute food and fluid intake, as well as manipulation of muscle glycogen and creatine stores, can artificially influence body composition estimates, particularly lean mass (Bone et al., 2017;Nana et al., 2012;Rouillier et al., 2015;Tinsley et al., 2017). Due to the confounding influence of the bone arrangement and organ mass in the trunk region and the likelihood that much of gastrointestinal content will appear as LST, it is theoretically appealing to remove this region for nonfasted body composition assessments. ...
... Dual-energy X-ray absorptiometry has been shown to overestimate BF% by 3.7% and produces rather large 95% limits of agreement (66.3%) when compared with a more advanced 5-compartment model (20). Moreover, there are potential issues with creatine/glycogen loading, hydration status, differences in hardware and software, weight limits, and errors in pixels containing bone (3,31). Therefore, future research should seek to determine the validity of MF-BIA to track changes in body composition after an RT program when using a more accepted criterion multicompartment model. ...
Article
Schoenfeld, BJ, Nickerson, BS, Wilborn, CD, Urbina, SL, Hayward, SB, Krieger, J, Aragon, AA, and Tinsley, G. Comparison of multifrequency bioelectrical impedance vs. dual-energy x-ray absorptiometry for assessing body composition changes after participation in a 10-week resistance training program. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to assess the ability of multifrequency bioelectrical impedance analysis (MF-BIA) to determine alterations in total and segmental body composition across a 10-week resistance training (RT) program in comparison with the criterion reference dual-energy X-ray absorptiometry (DXA). Twenty-one young male volunteers (mean ± SD; age = 22.9 ± 3.0 years; height = 175.5 ± 5.9 cm; body mass = 82.9 ± 13.6 kg; body mass index = 26.9 ± 3.6) performed an RT program that included exercises for all major muscle groups. Body composition was assessed using both methods before and after the intervention; change scores were determined by subtracting pre-test values from post-test values for percent body fat ([INCREMENT]%BF), fat mass ([INCREMENT]FM), and fat-free mass ([INCREMENT]FFM). Mean changes were not significantly different when comparing MF-BIA with DXA for [INCREMENT]%BF (-1.05 vs. -1.28%), [INCREMENT]FM (-1.13 vs. -1.19 kg), and FFM (0.10 vs. 0.37 kg, respectively). Both methods showed strong agreement for [INCREMENT]%BF (r = 0.75; standard error of the estimate [SEE] = 1.15%), [INCREMENT]FM (r = 0.84; SEE 1.0 kg), and [INCREMENT]FFM (r = 0.71; SEE of 1.5 kg). The 2 methods were poor predictors of each other in regards to changes in segmental measurements. Our data indicate that MF-BIA is an acceptable alternative for tracking changes in FM and FFM during a combined diet and exercise program in young, athletic men, but segmental lean mass measurements must be interpreted with circumspection.
... In addition, USG was measured to indicate hydration status. No significant differences and trivial to small effect sizes were observed in USG which suggests that (Bone et al. 2017) and acute reductions in blood volume (Georgiou et al. 1997). Previous research has shown that elevated oestrogen encourages retention of extracellular fluid in the vascular space, while elevated levels of both oestrogen and progesterone generally encourage retention of fluid within the interstitial space (Stachenfeld and Taylor 2004). ...
Article
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Purpose This study aimed to investigate the effect of fluctuating female hormones during the menstrual cycle (MC) and oral contraceptive (OC) cycle on different measures of body composition. Methods Twenty-two women with a natural MC and thirty women currently taking combined monophasic OC were assessed over three phases of the menstrual or oral contraceptive cycle. Body weight, skinfolds, bioelectric impedance analysis (BIA), ultrasound, dual-energy X-ray absorptiometry (DXA), and peripheral quantitative computed tomography (pQCT) measurements were performed to assess body composition. Urine specific gravity (USG) was measured as an indication of hydration, and serum oestradiol and progesterone were measured to confirm cycle phases. Results Five participants with a natural MC were excluded based on the hormone analysis. For the remaining participants, no significant changes over the MC and OC cycle were found for body weight, USG, skinfolds, BIA, ultrasound and pQCT measures. However, DXA body fat percentage and fat mass were lower in the late follicular phase compared to the mid-luteal phase of the MC, while for the OC cycle, DXA body fat percentage was higher and lean mass lower in the early hormone phase compared with the late hormone phase. Conclusion Our findings suggest that assessment of body fat percentage through BIA and skinfolds may be performed without considering the MC or OC cycle. Body adiposity assessment via DXA, however, may be affected by female hormone fluctuations and therefore, it may be advisable to perform repeat testing using DXA during the same phase of the MC or OC cycle.
... Recently, there has been increased awareness that, although DXA is useful for body composition assessment, it is not impervious to biological error induced by variation in subject presentation. Acute food and fluid intake, as well as manipulation of muscle glycogen and creatine stores, can artificially influence body composition estimates, particularly lean mass (Bone et al., 2017;Nana et al., 2012;Rouillier et al., 2015;Tinsley et al., 2017). Due to the confounding influence of the bone arrangement and organ mass in the trunk region and the likelihood that much of gastrointestinal content will appear as LST, it is theoretically appealing to remove this region for nonfasted body composition assessments. ...
Article
Implementation of an overnight fast is a pervasive recommendation prior to body composition assessment, but this is not always feasible. Previous research has indicated that, for dual-energy x-ray absorptiometry (DXA) scans, the trunk region may be particularly susceptible to biological error induced by food and fluid intake. This analysis explored the potential utility of excluding the trunk region from non-fasted DXA scans. Recreationally active adults were assessed by DXA after an overnight fast and again after consumption of standardized high-carbohydrate (HC) and low-carbohydrate (LC) diets. The effects of food consumption on total and appendicular lean soft tissue (LST; ALST) and ALST-derived skeletal muscle mass (SMM) were evaluated via analysis of variance, and metrics of reliability were calculated. In both conditions, constant error of non-fasted assessments was slightly lower when the trunk was excluded (ALST and SMM: 0.7 - 1.2%; LST: 1.5%). However, in both conditions, the total error (TE), SEE and limits of agreement (LOA) were higher for ALST and SMM (TE: 2.4 to 3.0%; SEE: 2.2 to 2.8%; LOA: 4.5 to 5.6%) than LST (TE: 2.1%; SEE: 1.3 to 1.4%; LOA: 2.5 to 2.8%) when expressed relative to mean values. The added technical error due to demarcation of body regions for ALST and SMM appears to outweigh the removal of biological error due to exclusion of the trunk. Although elimination of the trunk region is theoretically appealing for non-fasted DXA assessments, it is apparently an inferior method as compared to utilizing whole-body LST.
... The induction of dehydration or rehydration is another factor affecting measurements of lean tissue mass in active or trained populations. 24,25 These findings highlight the importance of considering TBW itself, or other factors likely to affect hydration status, when using DXA in research and practice. ...
Article
Background: The reliability of dual energy X-ray absorptiometry (DXA) to assess body composition is influenced by factors like hydration status. Hence, any factor affecting total body water (TBW) content, such as menstrual shifts in sex hormones, might influence DXA estimates of lean soft tissue (LST) and fat mass (FM). To address this possibility, interrelationships between menstrual fluctuations in sex hormones, LST and FM were examined in a premenopausal female. Methods: The participant was monitored over 40 consecutive days for LST, FM and TBW by bioelectrical impedance. Daily capillary blood samples were taken to track 17β-estradiol, progesterone, and luteinizing hormone (LH). Using a graphical vector autoregression model, variable interrelationships were tested in a contemporaneous network (same measurement window) and temporal network (next measurement window). Results: In the contemporaneous network, LST was related to TBW (r = 0.42) and FM (r = -0.34). The temporal network uncovered directional connections of TBW (r = 0.14), FM (r = -0.59) and LST (r = -0.50) on progesterone concentration. Hormonal interrelationships also emerged in the temporal network, whereby LH (r = 0.24) and 17β-estradiol (r = 0.13) were related to progesterone, and each hormone was related (r = 0.50-0.69) to itself. Conclusions: The menstrual profiling of a premenopausal female revealed interrelationships between body composition and water content, but sex hormone fluctuations did not correlate with TBW, FM and LST on the same day or following day in the hypothesized direction. The temporal between- and within-hormone linkages reflect those natural feedback loops that control hormone secretion.
... While we acknowledge that, for the newly licensed group, we only have access to the height and weight data, using the average for the group (165 cm and 51.9 kg, respectively) and calculating the body mass index at the current minimum weight of 46.6 kg with claim (3.2 kg), this would result in a body mass index of 17.1, which is at the very low end of the underweight scale. Additionally, although current DXA recommendations suggest that athletes present fasted and euhydrated (Nana et al., 2015), we acknowledge that many jockeys were dehydrated when scanned, which could have affected the accuracy of the DXA scans (Bone et al., 2017). ...
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Flat jockeys in Great Britain (GB) are classified as apprentices if they are aged less than 26 years and/or have ridden less than 95 winners. To gain experience, apprentices are allocated a weight allowance of up to 7 lb (3.2 kg). Given that there is no off-season in GB flat horseracing, jockeys are required to maintain their racing weight all year round. In light of recent work determining that current apprentices are considerably heavier than previous generations and that smaller increases have been made in the minimum weight, the aim of this study was to assess if the minimum weight in GB was achievable. To make the minimum weight (50.8 kg) with the maximal weight allowance requires a body mass of ∼46.6 kg while maintaining a fat mass >2.5 kg (the lowest fat mass previously reported in weight-restricted males). Thirty-two male apprentice jockeys were assessed for body composition using dual-energy X-ray absorptiometry. The mean ( SD ) total mass and fat mass were 56 (2.9) kg and 7.2 (1.8) kg, respectively. Given that the lowest theoretical body mass for this group was 51.2 (2.3) kg, only one of 32 jockeys was deemed feasible to achieve the minimum weight with their current weight allowance and maintaining fat mass >2.5 kg. Furthermore, urine osmolality of 780 (260) mOsmol/L was seen, with 22 (out of 32) jockeys classed as dehydrated (>700 mOsmols/L), indicating that body mass would be higher when euhydrated. Additionally, we observed that within new apprentice jockeys licensed during this study ( N = 41), only one jockey was able to achieve the minimum weight. To facilitate the goal of achieving race weight with minimal disruptions to well-being, the authors’ data suggest that the minimum weight for GB apprentices should be raised.
... It was attributed to the increase of muscle glycogen concentration, which is observed after a carbohydrate load, while it is estimated that glycogen is bound to water at a range of up to 400% of its mass [57]. It is confirmed by general results indicating the effect of glycogen loading on the total body water content measured for athletes [58] and resulting improvement of obtained sport results [59]. ...
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Background and objectives: Some publications indicate the possibility of the influence of meal nutritional value on results of bioelectrical impedance, and of the relation between the long-term carbohydrate intake and body composition. The aim of the presented study was to evaluate the influence of long-term intake of carbohydrates on body composition results assessed using the bioelectrical impedance of Caucasian young women with normal body mass, who were in the follicular phase of their menstrual cycle. Materials and Methods: Body composition was assessed in 100 women (18–30 years), according to strict rules, to minimize the influence of disturbing factors and by using two types of bioelectrical impedance device of the same operator to eliminate the influence of measurement (BIA 101/SC and BIA 101/ASE by Akern Srl, Firenze, Italy with the Bodygram 1.31 software and its equations by Akern Srl, Firenze, Italy). The analysis included validation of reproducibility of body composition assessment (fat, fat-free, body cell and muscle mass, water, extracellular water, and intracellular water content), and comparison of body composition for groups characterized by carbohydrate content <50% (n = 55) and >50% of the energy value of the diet (n = 45). Results: Analysis conducted using Bland–Altman method, analysis of correlation, analysis of quartile distribution, and weighted κ statistic revealed a positively validated reproducibility, but extracellular water associations were the weakest. Depending on the device, participants characterized by higher carbohydrate intake had significantly higher intracellular water content (p = 0.0448), or close to significantly higher (p = 0.0851) than those characterized by lower carbohydrate intake, whose extracellular water content was close to significantly lower (p = 0.0638) or did not differ. Conclusions: The long-term, moderately reduced, carbohydrate intake may cause the shift of intracellular water to the extracellular space and, as a result, influence the body composition results.
... In our study, although the majority of changes in LBM, as assessed by DXA, occurred by week 6, the increase in VL MT increased at a steady rate over the 12 weeks. The more rapid increase in LBM for the first six weeks may reflect physiological changes in addition to muscle growth resulting from training, such as increased muscle glycogen storage [50], and its associated water storage [51], and consequently LBM readings through DXA [52] and potentially ultrasound readings [53]. Although the change in VL thickness did not quite reach statistical significance (p = 0.08), the change observed in the present study was close to that reported in other studies at similar locations [35,54,55]. ...
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There are conflicting reports regarding the efficacy of plant versus animal-derived protein to support muscle and strength development with resistance training. The purpose of this study was to determine whether soy and whey protein supplements matched for leucine would comparably support strength increases and muscle growth following 12 weeks of resistance training. Sixty-one untrained young men (n = 19) and women (n = 42) (18–35 year) enrolled in this study, and 48 completed the trial (17 men, 31 women). All participants engaged in supervised resistance training 3×/week and consumed 19 grams of whey protein isolate or 26 grams of soy protein isolate, both containing 2 g (grams) of leucine. Multi-level modeling indicated that total body mass (0.68 kg; 95% CI: 0.08, 1.29 kg; p < 0.001), lean body mass (1.54 kg; 95% CI: 0.94, 2.15 kg; p < 0.001), and peak torque of leg extensors (40.27 Nm; 95% CI: 28.98, 51.57 Nm, p < 0.001) and flexors (20.44 Nm; 95% CI: 12.10, 28.79 Nm; p < 0.001) increased in both groups. Vastus lateralis muscle thickness tended to increase, but this did not reach statistical significance (0.12 cm; 95% CI: −0.01, 0.26 cm; p = 0.08). No differences between groups were observed (p > 0.05). These data indicate that increases in lean mass and strength in untrained participants are comparable when strength training and supplementing with soy or whey matched for leucine.
... Additionally, the participants' diets were controlled and sufficient energy and protein intake were assured. No differences regarding dietary intake were detected, which is in our view important, since a glycogen increase from a higher carbohydrate intake might have confounded the body composition results (Bone et al., 2017;Rouillier, David-Riel, Brazeau, St-Pierre, & Karelis, 2015). We accounted for variation in TBW throughout the intervention, with no significant changes being detected. ...
Article
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 < 0.05). No statistically significant between-group or group-by-time interactions were observed. Supplementation with HMB (FA and Ca) or α-HICA failed to enhance body composition to a greater extent than placebo. We do not recommend these leucine metabolites for improving body composition changes with RET in young adult resistance trained men.
... Indeed, during weeks 7-28, FFM increased in the lower limbs (1.0 and 1.0 kg in the injured and non-injured limb, respectively) and trunk (0.7 kg), collectively contributing to an increase in whole body FFM of 2.9 kg (though it is acknowledged that this may also be in due part to glycogen storage associated with increased daily CHO intakes, Bone et al., 2017). During this time, whole body fat mass also increased by 0.7 kg. ...
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Maintaining muscle mass and function during rehabilitation from anterior cruciate ligament injury is complicated by the challenge of accurately prescribing daily energy intakes aligned to energy expenditure. Accordingly, we present a 38-week case study characterizing whole body and regional rates of muscle atrophy and hypertrophy (as inferred by assessments of fat-free mass from dual-energy X-ray absorptiometry) in a professional male soccer player from the English Premier League. In addition, in Week 6, we also quantified energy intake (via the remote food photographic method) and energy expenditure using the doubly labeled water method. Mean daily energy intake (CHO: 1.9-3.2, protein: 1.7-3.3, and fat: 1.4-2.7 g/kg) and energy expenditure were 2,765 ± 474 and 3,178 kcal/day, respectively. In accordance with an apparent energy deficit, total body mass decreased by 1.9 kg during Weeks 1-6 where fat-free mass loss in the injured and noninjured limb was 0.9 and 0.6 kg, respectively, yet, trunk fat-free mass increased by 0.7 kg. In Weeks 7-28, the athlete was advised to increase daily CHO intake (4-6 g/kg) to facilitate an increased daily energy intake. Throughout this period, total body mass increased by 3.6 kg (attributable to a 2.9 and 0.7 kg increase in fat free and fat mass, respectively). Our data suggest it may be advantageous to avoid excessive reductions in energy intake during the initial 6-8 weeks post anterior cruciate ligament surgery so as to limit muscle atrophy.
... However, the reference values reported by the present investigation may not be applicable to other DXA devices, as differences in hardware, software, and correction factors may reduce the agreement between the estimates of body composition from different systems (Hull et al., 2009). Similarly, factors such as variation in FFM density (Prior et al., 2001), creatine or carbohydrate loading (Bone et al., 2017), and pre-testing dietary intake (Rouillier, David-Riel, Brazeau, St-Pierre, & Karelis, 2015) can affect body composition estimates. ...
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Fat-free mass index (FFMI) is a height-adjusted metric of fat-free mass which has been suggested as a useful method of body composition assessment in athletic populations. The purpose of this study was to determine sport-specific FFMI values and the natural upper threshold of FFMI in female athletes. 372 female collegiate athletes (Mean±SD; 20.03±1.55 years, 167.55±7.50 cm, 69.46±13.04 kg, 24.18±5.48% bodyfat) underwent body composition assessment via dual-energy x-ray absorptiometry. FFMI was adjusted to height via linear regression and sport-specific reference values were determined. Between-sport differences were identified using one-way ANOVA with Tukey post-hoc tests. Average FFMI was 18.82±2.08 kg/m²; height-adjusted values were not significantly different (p<0.05) than unadjusted values. FFMI in rugby athletes (20.09±2.23 kg/m²) was found to be significantly higher (p<0.05) than in gymnastics (18.62±1.12 kg/m²), ice hockey (17.96±1.04 kg/m²), lacrosse (18.58±1.84 kg/m²), swim & dive (18.16±1.67 kg/m²), and volleyball (18.04±1.13 kg/m²). FFMI in cross country (16.56±1.14 kg/m²) and synchronized swimming (17.27±1.47 kg/m²) was significantly lower (p<0.05) than in Olympic weightlifting (19.69±1.98 kg/m²), wrestling (19.15±2.47 kg/m²), and rugby. The upper threshold for FFMI in female athletes (97.5th percentile) was 23.90 kg/m². These results can be used to guide personnel decisions and assist with long-term body composition, training, and nutritional goals.
... Methodological issues associated with the quantification of key outcome measures such as energy intake, energy expenditure and body composition are also very relevant when attempting to interpret the literature. For example, an increase in dietary carbohydrate intake to facilitate a positive energy balance will acutely increase muscle metabolites and associated water content, significantly influencing estimates of body composition via dual energy x-ray absorptiometry (163), and other commonly used techniques, including air displacement plethysmography and bioimpedance analysis (164), while acute resistance exercise induced water retention can influence magnetic resonance imaging estimates of muscle cross-sectional area for at least 52 h (165). Given such physique assessment nuances, concurrent review of associated functional capacity adaptations would appear pertinent for future investigations. ...
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Resistance training is commonly prescribed to enhance strength/power qualities and is achieved via improved neuromuscular recruitment, fiber type transition, and/ or skeletal muscle hypertrophy. The rate and amount of muscle hypertrophy associated with resistance training is influenced by a wide array of variables including the training program, plus training experience, gender, genetic predisposition, and nutritional status of the individual. Various dietary interventions have been proposed to influence muscle hypertrophy, including manipulation of protein intake, specific supplement prescription, and creation of an energy surplus. While recent research has provided significant insight into optimization of dietary protein intake and application of evidence based supplements, the specific energy surplus required to facilitate muscle hypertrophy is unknown. However, there is clear evidence of an anabolic stimulus possible from an energy surplus, even independent of resistance training. Common textbook recommendations are often based solely on the assumed energy stored within the tissue being assimilated. Unfortunately, such guidance likely fails to account for other energetically expensive processes associated with muscle hypertrophy, the acute metabolic adjustments that occur in response to an energy surplus, or individual nuances like training experience and energy status of the individual. Given the ambiguous nature of these calculations, it is not surprising to see broad ranging guidance on energy needs. These estimates have never been validated in a resistance training population to confirm the “sweet spot” for an energy surplus that facilitates optimal rates of muscle gain relative to fat mass. This review not only addresses the influence of an energy surplus on resistance training outcomes, but also explores other pertinent issues, including “how much should energy intake be increased,” “where should this extra energy come from,” and “when should this extra energy be consumed.” Several gaps in the literature are identified, with the hope this will stimulate further research interest in this area. Having a broader appreciation of these issues will assist practitioners in the establishment of dietary strategies that facilitate resistance training adaptations while also addressing other important nutrition related issues such as optimization of fuelling and recovery goals. Practical issues like the management of satiety when attempting to increase energy intake are also addressed.
... Carbohydrate restriction from a VLCD results in rapid mobilisation of glycogen from liver and muscle tissue and also dynamic shifts of intra-cellular and extracellular water from this tissue marked by substantial diuresis [49,50]. This is a confounding factor which may inadvertently overstate the reduction in LBM by approximately 1 kg [51][52][53]. As a result, previous research highlights the need to analyse body composition with combined information from DXA and bioelectrical impedance analysis (BIA) to correctly define these LBM changes [50,52,54]. ...
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Background Fatty liver in obese patients increases the technical difficulty of bariatric surgery. Pre-operative weight loss with a very-low-calorie diet (VLCD) is commonly used to facilitate surgery. Few studies have quantified the systemic effect of rapid pre-operative weight loss on body composition. The objective of this study is to evaluate body composition changes in bariatric surgery patients undergoing a VLCD. Methods Body composition assessments were performed between August 2017 and January 2019 using dual-energy X-ray absorptiometry immediately before and after a 2-week VLCD at St Vincent’s Hospital Melbourne. Data collected prospectively pre- and post-VLCD included total body weight, excess body weight, body mass index (BMI), lean body mass (LBM), fat mass (FM) and bone mineral content (BMC). The pre- and post-operative results were compared. Results Forty-four patients completed both the 2-week VLCD and body composition assessments. Following a 2-week VLCD, patients lost a mean of 4.5 kg (range − 0.3 to 9.5) in a total body weight and 8.8% (range − 0.9 to 17.1) of excess body weight, with a mean reduction in body mass index of 1.6 kg/m² (range − 0.2 to 3.1). Loss of LBM was 2.8 kg and was significantly greater than loss of FM, 1.7 kg (p < 0.05). BMC changes were insignificant. Conclusion A VLCD is an effective tool for pre-operative weight reduction. In this cohort, a large amount of the total weight loss was attributed to a loss of lean body mass. The impact of significant lean body mass loss and its relationship to short- and long-term health outcomes warrants further assessment.
... Previous research has observed DXAderived losses in fat-free soft tissue mass across a 14-day sleep restriction period, although the magnitude of this effect was likely enhanced by the calorie-restricted diet employed (Nedeltcheva et al., 2010). Nevertheless, the current intervention duration was likely too short to detect changes in lean mass with DXA (given the variability of the measure; Bone et al. (2017)) and future investigations of similar durations should consider incorporating direct measures of muscle mass (i.e., with MRI or CSA).Whilst our data reports a significantly lower rate of MyoPS (~19%) with sleep restriction, it is unclear with the current study design how this compares to baseline rates of MyoPS. As such, future studies may incorporate a baseline measurement into the study as a comparison measurement. ...
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Key points: Sleep restriction has previously been associated with the loss of muscle mass in both human and animal models. The rate of myofibrillar protein synthesis (MyoPS) is a key variable in regulating skeletal muscle mass and can be increased by performing high-intensity interval exercise (HIIE), but the effect of sleep restriction on MyoPS is unknown. In this study, we demonstrate that participants undergoing a sleep restriction protocol (5 nights, with 4 h time in bed each night) had lower rates of skeletal muscle MyoPS; however, rates of MyoPS were maintained at control levels by performing HIIE during this period. Our data suggest that the lower rates of MyoPS in the sleep restriction group may contribute to the detrimental effects of sleep loss on muscle mass and that HIIE may be used as an intervention to counteract these effects. Abstract: The aim of this study was to investigate the effect of sleep restriction, with or without high-intensity interval exercise (HIIE), on the potential mechanisms underpinning previously-reported sleep-loss-induced reductions to muscle mass. Twenty-four healthy, young men underwent a protocol consisting of two nights of controlled baseline sleep and a five-night intervention period. Participants were allocated into one of three parallel groups, matched for age, V̇O2peak , BMI, and habitual sleep duration; a normal sleep group (NS, 8 h time in bed (TIB) each night), a sleep restriction group (SR, 4 h TIB each night), and a sleep restriction and exercise group (SR+EX, 4 h TIB each night, with three sessions of HIIE). Deuterium Oxide (D2 O) was ingested prior to commencing the study, and muscle biopsies obtained pre- and post-intervention were used to assess myofibrillar protein synthesis (MyoPS) and molecular markers of protein synthesis and degradation signalling pathways. MyoPS was lower in the SR group (FSR %/day ± SD, 1.24 ± 0.21), compared to both the NS (1.53 ± 0.09) and SR+EX groups (1.61 ± 0.14), (P < 0.05). However, there were no changes in the purported regulators of protein synthesis (i.e., p-AKTser473 and p-mTORser2448 ) and degradation (i.e., Foxo1/3 mRNA and LC3 protein) in any group. These data suggest that MyoPS is acutely reduced by sleep restriction, but that MyoPS can be maintained by performing HIIE. These findings may explain the sleep-loss-induced reductions in muscle mass previously reported, and highlight the potential therapeutic benefit of HIIE to maintain myofibrillar remodelling in this context. This article is protected by copyright. All rights reserved.
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Introduction/Background Few investigations have sought to explain discrepancies between dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) body composition estimates. The purpose of this analysis was to explore physiological and anthropometric predictors of discrepancies between DXA and BIA total and segmental body composition estimates. Methodology Assessments via DXA (GE® Lunar Prodigy) and single-frequency BIA (RJL Systems® Quantum V) were performed in 179 adults (103 F, 76 M, age: 33.6 ± 15.3 y; BMI: 24.9 ± 4.3 kg/m²). Potential predictor variables for differences between DXA and BIA total and segmental fat mass (FM) and lean soft tissue (LST) estimates were obtained from demographics and laboratory techniques, including DXA, BIA, bioimpedance spectroscopy, air displacement plethysmography, and 3-dimensional optical scanning. To determine meaningful predictors, Bayesian robust regression models were fit using a t-distribution and regularized hierarchical shrinkage “horseshoe” prior. Standardized model coefficients (β) were generated, and leave-one-out cross validation (LOO) was used to assess model predictive performance. Results LST hydration (i.e., total body water:LST) was a predictor of discrepancies in all FM and LST variables (|β|:0.20-0.82). Additionally, extracellular fluid percentage was a predictor for nearly all outcomes (|β|:0.19-0.40). Height influenced the agreement between whole-body estimates (|β|:0.74-0.77), while the mass, length, and composition of body segments were predictors for segmental LST estimates (|β|:0.23-3.04). Predictors of segmental FM errors were less consistent. Select sex-, race-, or age-based differences between methods were observed. The accuracy of whole-body models was superior to segmental models (LOO-adjusted R² of 0.83-0.85 for FMTOTAL and LSTTOTAL vs. 0.20-0.76 for segmental estimates). For segmental models, predictive performance decreased in the order of: appendicular lean soft tissue, LSTLEGS, LSTTRUNK and FMLEGS, FMARMS, FMTRUNK, and LSTARMS. Conclusions These findings indicate the importance of LST hydration, extracellular fluid content, and height for explaining discrepancies between DXA and BIA body composition estimates. These general findings and quantitative interpretation based on the presented data allow for a better understanding of sources of error between two popular segmental body composition techniques and facilitate interpretation of estimates from these technologies.
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In this study, we compare the effects of isocaloric high (HIGH: 2 g.kg‐1.d‐1, n = 19) and low protein diet (LOW: 1 g.kg‐1.d‐1, n = 19) on changes in body composition, muscle strength, and endocrine variables in response to a 10‐day military field exercise with energy deficit, followed by seven days of recovery. Body composition (DXA), one repetition maximum (1RM) bench and leg press, counter movement jump height (CMJ) and blood variables were assessed before and after the exercise. Performance and blood variables were reassessed after seven days of recovery. The 10‐day exercise resulted in, severe energy deficit in both LOW and HIGH (‐4373 ± 1250, ‐4271 ± 1075 kcal.d‐1), and led to decreased body mass (‐6.1%, ‐5.2%), fat mass (‐40.5%, ‐33.4%), 1RM bench press (‐9.5%, ‐9.7%), 1RM leg press (‐7.8%, ‐8.3%) and CMJ (‐14.7%, ‐14.6%), with no differences between groups. No change was seen for fat free mass. In both groups, the exercise led to a switch towards a catabolic physiological milieu, evident as reduced levels of anabolic hormones (testosterone, IGF‐1) and increased levels of cortisol (more pronounced in HIGH, p<0.05). Both groups also displayed substantial increases in creatine kinase. After seven days of recovery, most variables had returned to close‐to pre‐exercise levels, except for CMJ, which remained at reduced levels. In conclusion, increased protein intake during 10‐day of military field exercise with severe energy deficiency did not mitigate loss of body mass or impairment of physical performance.
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Rugby League is a team sport requiring players to experience large impact collisions, thus requiring high amounts of muscle mass. Many players (academy and senior) strive to increase muscle mass during the pre-season, however, quantification of changes during this period have not been thoroughly investigated. We therefore assessed changes in body-composition using Dual X-Ray Absorptiometry (DXA) in eleven academy players over three successive pre-seasons and ninety-three senior players from four different European Super League clubs prior to, and at the end of, a pre-season training period. There was no meaningful change in lean mass of the academy players during any of the pre-season periods (year 1 = 72.3 ± 7.1 to 73.2 ± 7.2 kg; ES 0.05, year 2 = 74.4 ± 6.9 to 75.5 ± 6.9 kg; ES 0.07, year 3 = 75.9 ± 6.7 to 76.8 ± 6.6 kg; ES 0.06) with small changes only occurring over the three-year study period (72.3 to 75.9 kg; ES = 0.22). Senior players showed trivial changes in all characteristics during the pre-season period (total mass = 95.1 to 95.0 kg; ES -0.01, lean mass = 74.6 to 75.1 kg; ES 0.07, fat mass = 13.6 to 12.9 kg; ES -0.17, body fat percentage = 14.8 to 14.1%; ES -0.19). These data suggest that academy players need time to develop towards profiles congruent with senior players. Moreover, once players reach senior level, body-composition changes are trivial during the pre-season and therefore teams may need to individualise training for players striving to gain muscle mass by reducing other training loads.
Article
Lytle, JR, Stanelle, ST, Kravits, DM, Ellsworth, RL, Martin, SE, Green, JS, and Crouse, SF. Effects of an acute strength and conditioning training session on dual-energy x-ray absorptiometry results. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to determine whether an athletic strength and conditioning (S&C) session will alter body composition estimates of a dual-energy x-ray absorptiometry (DXA) scan. Twenty-two strength-trained individuals (15 men, 7 women, 24 ± 2 years, 174.2 ± 8.5 cm, 83.5 ± 15.0 kg) volunteered to participate in the study. Each subject underwent 2 DXA scans, before and after completion of the S&C session, which consisted of upper- and lower-body resistance exercises and interval running. Subjects consumed a free-living meal before the first scan, after which only ad libitum water intake was consumed until completing the second scan. Results were analyzed through sex by time repeated-measures analysis of variance. If no interaction effect was observed, results were next analyzed through correlated t-test (α = 0.05). Significant sex by time interactions were observed for arm total and lean mass, as well as a significant main effect of time showing a decrease in arm lean mass after the S&C session. Values before and after the S&C session that resulted in significant differences via correlated t-test are displayed in Table 1. Results revealed a significant decrease in total mass, arm and leg percent fat, and trunk lean mass, and an increase in leg lean mass.
Chapter
Dual energy X-ray absorptiometry is used for the assessment of physique traits of athletes. Given the use of X-rays and thus exposure to radiation, specific training by a suitably accredited national organisation is required before dual energy X-ray absorptiometry can be operated, and consideration of the cumulative X-ray dose for athletes needs to be considered. Standardisation of subject presentation (euhydrated and glycogen replete, overnight fasted and in minimal clothing) and positioning on the scanning bed (centrally aligned in a standard position using custom-made positioning aids) and manipulation of the automatic segmentation of regional areas of the scan results are necessary. The International Society for Clinical Densitometry has established good clinical practice guidelines relating to the acquisition and analysis of dual energy X-ray absorptiometry data.
Chapter
Physique traits are one of an array of variables known to influence performance of athletes across a wide range of sports. The routine monitoring of physique traits has become common practice amongst athletic populations, affording an opportunity to objectively assess the impact of training and diet and subsequently adjust these variables to optimise adaptations. An array of techniques is available to assess the physique traits of athletes. When selecting the most appropriate technique, a range of factors should be considered, including technical (safety, validity, precision and accuracy of measurement) and practical issues (availability, financial implications, portability, invasiveness, time effectiveness and technical expertise necessary), including the ability of the technique to accommodate the unique physique traits of athletes. Guidelines to assist with facilitating standardisation of athlete presentation prior to assessments are provided, with application to the majority of physique assessment techniques commonly applied amongst athletic populations such as dual-energy X-ray absorptiometry, air displacement plethysmography (i.e. Bod Pod) and bioelectrical impedance analysis. The exception may be surface anthropometry given results are minimally impacted by athlete presentation.
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Whilst the assessment of body composition is routine practice in sport, there remains considerable debate on the best tools available, with the chosen technique often based upon convenience rather than understanding the method and its limitations. The aim of this manuscript was threefold: 1) provide an overview of the common methodologies used within sport to measure body composi-tion, specifically hydro-densitometry, air displacement plethysmography, bioelectrical imped-ance analysis and spectroscopy, ultra-sound, three dimensional scanning, dual-energy x-ray ab-sorptiometry (DXA) and skinfold thickness; 2) compare the efficacy of what are widely believed to be the most accurate (DXA) and practical (skinfold thickness) assessment tools and 3) provide a framework to help select the most appropriate assessment in applied sports practice including insights from the authors’ experiences working in elite sport. Traditionally, skinfold thickness has been the most popular method of body composition but in recent years the use of DXA has in-creased, with a wide held belief that it is the criterion standard. When bone mineral content needs to be assessed, and/or when it is necessary to take limb specific estimations of fat and fat free mass, then DXA appears to be the preferred method; although it is crucial to be aware of the logis-tical constraints required to produce reliable data, including controlling food intake, prior exer-cise and hydration status. However, given the need for simplicity and after considering the evi-dence across all assessment methods, skinfolds appear to be the least affected by day-to-day var-iability, leading to the conclusion ‘come back skinfolds, all is forgiven’.
Article
Objectives To investigate the impact of acute food and fluid intake or hydration status on the standardised brightness-mode ultrasound measurement of subcutaneous adipose tissue thickness. Design Thirty active adults (female n = 10) participated in a randomised cross over study Methods Participants completed three body composition assessment sessions via standardised brightness-mode ultrasound and Dual-energy X-ray absorptiometry. Participants were assessed under standardised presentation during ‘food only’ and ‘food plus water’ sessions at baseline and reassessed after their allotted intake. ‘Hypohydration plus water’ was undertaken in a hypohydrated state at baseline and reassessed after water intake. Results The sum of eight subcutaneous adipose tissue thickness was lower when measured after ‘food only’ or ‘food plus water’ compared to baseline (-0.1 – -0.9 mm; p < 0.01). However, these changes were less than the 95% confidence interval of the technical error of measurement of the investigator. Body mass, Dual-energy X-ray absorptiometry total and trunk mass, lean mass and trunk lean mass estimates increased (p < 0.01) following ‘food only’ or “food plus water’, and decreased with hypohydration (p < 0.01). Total and regional fat mass estimates were not impacted. Conclusions The sum of eight subcutaneous adipose tissue thickness measured via standardised brightness-mode ultrasound was unaffected by acute food and fluid consumption or hydration status changes. Comparatively, these interventions altered Dual-energy x-ray absorptiometry body composition estimates, especially that of lean mass components. Standardised brightness-mode ultrasound can therefore be used to monitor changes in fat patterning when standardised client presentation is not practically achievable.
Article
Background Physical and psychological stress alter gut-brain axis activity, potentially causing intestinal barrier dysfunction that may, in turn, induce cognitive and mood impairments through exacerbated inflammation and blood brain barrier (BBB) permeability. These interactions are commonly studied in animals or artificial laboratory environments. However, military survival training provides an alternative and unique human model for studying the impacts of severe physical and psychological stress on the gut-brain axis in a realistic environment. Purpose To determine changes in intestinal barrier and BBB permeability during stressful military survival training and identify relationships between those changes and markers of stress, inflammation, cognitive performance, and mood state. Materials and Methods Seventy-one male U.S. Marines (25.2±2.6 years) were studied during Survival, Evasion, Resistance, and Escape (SERE) training. Measurements were conducted on day 2 of the 10-day classroom phase of training (PRE), following completion of the 7.5-day field-based simulation phase of the training (POST), and following a 27-day recovery period (REC). Fat-free mass (FFM) was measured to assess the overall physiologic impact of the training. Biomarkers of intestinal permeability (liposaccharide-binding protein [LBP]) and BBB permeability (S100 calcium-binding protein B [S100B]), stress (cortisol, dehydroepiandrosterone sulfate [DHEA-S] epinephrine, norepinephrine) and inflammation (interleukin-6 [IL-6], high-sensitivity C-reactive protein [hsCRP]) were measured in blood. Cognitive performance was assessed by psychomotor vigilance (PVT) and grammatical reasoning (GR) tests, and mood state by the Profile of Mood States (total mood disturbance; TMD), General Anxiety Disorder-7 (GAD-7), and Patient Health (PHQ-9) questionnaires. Results FFM, psychomotor vigilance, and LBP decreased from PRE to POST, while TMD, anxiety, and depression scores, and S100B, DHEA-S, IL-6, norepinephrine, and epinephrine concentrations all increased (all p≤0.01). Increases in DHEA-S were associated with decreases in body mass (p=0.015). Decreases in FFM were associated with decreases in LBP concentrations (p=0.015), and both decreases in FFM and LBP were associated with increases in TMD and depression scores (all p<0.05) but not with changes in cognitive performance. Conversely, increases in S100B concentrations were associated with decreases in psychomotor vigilance (p<0.05) but not with changes in mood state or LBP concentrations. Conclusions Evidence of increased intestinal permeability was not observed in this military survival training-based model of severe physical and psychological stress. However, increased BBB permeability was associated with stress and cognitive decline, while FFM loss was associated with mood disturbance, suggesting that distinct mechanisms may contribute to decrements in cognitive performance and mood state during the severe physical and psychological stress experienced during military survival training.
Article
Negative energy balance during military operations can be severe and result in significant reductions in fat-free mass (FFM). Consuming supplemental high-quality protein following such military operations may accelerate restoration of FFM. Body composition (dual-energy x-ray absorptiometry) and whole-body protein turnover (single-pool (15)N-alanine method) were determined before (PRE) and after 7 d (POST) of severe negative energy balance during military training in 63 male US Marines (mean±SD, 25±3 y, 84±9 kg). After POST measures were collected, volunteers were randomized to receive higher-protein (HIGH: 1103 kcal/d, 133 g protein/d), moderate protein (MOD: 974 kcal/d, 84 g protein/d), or carbohydrate-based low protein control (CON: 1042 kcal/d, 7 g protein/d) supplements, in addition to a self-selected, ad libitum diet, for the 27 d intervention (REFED). Measurements were repeated POST-REFED. POST total body mass (TBM, -5.8±1.0 kg, -7.0%), FFM (-3.1±1.6 kg, -4.7%), and net protein balance (-1.7±1.1 g protein/kg/d) were lower and proteolysis (1.1±1.9 g protein/kg/d) was higher compared to PRE (P<0.05). Self-selected, ad libitum dietary intake during REFED was similar between groups (3507 ± 730 kcal/d, 2.0±0.5 g protein/kg/d). However, diets differed by protein intake due to supplementation (CON: 2.0±0.4, MOD: 3.2±0.7, HIGH: 3.5±0.7 g/kg/d; P<0.05) but not total energy (4498±725 kcal/d). All volunteers, independent of group assignment, achieved positive net protein balance (0.4±1.0 g protein/kg/d) and gained TBM (5.9±1.7 kg, 7.8%) and FFM (3.6±1.8 kg, 5.7%) POST-REFED compared to POST (P<0.05). Supplementing ad libitum, energy-adequate, higher-protein diets with additional protein may not be necessary to restore FFM after short-term severe negative energy balance.
Article
It is usually stated that glycogen is stored in human muscle bound to water in a proportion of 1:3 g. We investigated this proportion in biopsy samples during recovery from prolonged exercise. On two occasions, nine aerobically trained subjects ([Formula: see text] = 54.4 ± 1.05 mL kg(-1) min(-1); mean ± SD) dehydrated 4.6 ± 0.2 % by cycling 150 min at 65 % [Formula: see text] in a hot-dry environment (33 ± 4 °C). One hour after exercise subjects ingested 250 g of carbohydrates in 400 mL of water (REHLOW) or the same syrup plus water to match fluid losses (i.e., 3170 ± 190 mL; REHFULL). Muscle biopsies were obtained before, 1 and 4 h after exercise. In both trials muscle water decreased from pre-exercise similarly by 13 ± 6 % and muscle glycogen by 44 ± 10 % (P < 0.05). After recovery, glycogen levels were similar in both trials (79 ± 15 and 87 ± 18 g kg(-1) dry muscle; P = 0.20) while muscle water content was higher in REHFULL than in REHLOW (3814 ± 222 vs. 3459 ± 324 g kg(-1) dm, respectively; P < 0.05; ES = 1.06). Despite the insufficient water provided during REHLOW, per each gram of glycogen, 3 g of water was stored in muscle (recovery ratio 1:3) while during REHFULL this ratio was higher (1:17). Our findings agree with the long held notion that each gram of glycogen is stored in human muscle with at least 3 g of water. Higher ratios are possible (e.g., during REHFULL) likely due to water storage not bound to glycogen.
Article
19 subjects performed prolonged heavy arm and leg exercise after which they had a protein and fat diet for three days. Thereafter they switched to a carbohydrate enriched diet during a 4-day period. The measurements were performed on the 3rd day and then repeated on the 7th day. The glycogen concentration in the thigh and the arm muscles was 4.5 and 2.6 g/kg wet muscle on the 3rd day and increased with the carbohydrate enriched diet to 19.9 and 16.9 g/kg wet muscle, respectively. Body weight increased 2.4 kg during this period of 4 days. The total body water increased 2.2 1 which is assumed to be caused by the glycogen storage in the muscles and the liver. The amount of glycogen stored was calculated to be at least 500 g, which means that 3—4 g of water is bound with each gram of glycogen.