35 research outputs found
Evaluation of Fat-free Mass Characteristics at Different Adiposity Levels: Impact of Weight Status Stratification Method
The method used to stratify weight status when evaluating fat-free mass (FFM) characteristics has primarily been based upon body mass index (BMI) and not body fat percent (BF%). As a result, it is unknown whether deviations in FFM characteristics are similar when stratifying weight status based upon BMI or BF%. Purpose: The purpose of this study was to evaluate FFM characteristics at different adiposity levels when stratifying weight status via BMI and BF%. Methods: 150 adults (50% males) participated in this study. 3-compartment (3C) model body composition was based upon body density (Db) via air displacement plethysmography (ADP) and total body water via bioimpedance analysis. FFM density (DFFM), residual (RFFM), and hydration (HFFM)were evaluated in all subjects. The Db obtained from a stand-alone assessment of ADP (2C-Db) and 3C model (3C-Db)were also compared between groups. Subjects were stratified based upon weight status (BMI and BF%). First, subjects were divided into a normal weight (NW-BMI), overweight (OW-BMI) or obese (OB-BMI) group, which were based upon BMI values of 18.5-24.99 kg/m2 (n=50), 25.0-29.99 kg/m2 (n=50), and ³ 30.0 kg/m2 (n=50), respectively. Next, subjects were divided into groups based upon BF% where normal weight BF% values (NW-BF%) for males and females were \u3c 25 and 35% (n=81), respectively, and obese BF% values (OB-BF%) were ³25 and 35% (n=69), respectively. Results: The DFFM ranged from 1.096 – 1.097 g/cm3 for all groups in both weight status stratification methods (all p \u3e 0.05). HFFM and RFFM were similar for all comparisons and ranged from 73.99 – 74.33% and 25.67 – 26.01%, respectively, for BMI groups and 74.02 – 74.26% and 25.74 – 25.98%, respectively, for BF% groups (all p \u3e 0.05). In contrast, the 3C-Db (1.050, 1.036, and 1.013 g/cm3) and 2C-Db (1.051, 1.036, and 1.014 g/cm3) were statistically significant for all comparisons between NW-BMI, OW-BMI, and OB-BMI respectively (all p \u3c 0.05). Furthermore, 3C-Db (1.051 and 1.011 g/cm3) and 2C-Db (1.052 and 1.012 g/cm3) were significantly different when comparing NW-BF% and OB-BF% (both p \u3c 0.05). CONCLUSIONS: Previous research has reported the FFM characteristics when stratifying weight status via BMI classification. As a result, it was unknown whether deviations in FFM characteristics existed when stratifying by BF%. Uniquely, the current study findings revealed that FFM characteristics are similar between groups regardless of the weight status stratification method (BMI or BF%)
Central Hemodynamics Measured During 5 Repetition Maximum Free Weight Resistance Exercise
International Journal of Exercise Science 11(2): 342-354, 2018. The PhysioFlowâ„¢ is a piece of equipment that uses bioimpedance cardiography to measure central hemodynamics. The purpose of this research was to explore the novel approach of monitoring central hemodynamics during free weight resistance exercise using bioimpedance cardiography throughout a 5 repetition maximum (5RM). Thirty participants ranging from beginner to advanced lifters (16 males and 14 females) completed a 5RM for back squat, seated push press, and bicep curl while connected to the PhysioFlowâ„¢ to assess the response of heart rate (HR), stroke volume (SV), cardiac output (Q), and ejection fraction (EF). Participants were cued for form and to breathe normally throughout the lifts. The PhysioFlowâ„¢ detected an increase in HR and Q for all lifts between rest and each repetition (p \u3c 0.05). There was also an increase in HR and Q from repetition 1 to repetition 5 for all lifts (p \u3c 0.05). No changes in EF or SV were detected between resting measurements and each repetition for all lifts (p \u3e 0.05) and no changes in EF or SV were detected when all repetitions were compared to each other for all lifts (p \u3e 0.05). In conclusion, the PhysioFlowâ„¢ was able to detect changes in HR and Q during dynamic free weight resistance exercise. This novel approach may provide a mechanism for monitoring central hemodynamics during free weight resistance training. However, more research needs to be conducted as the exercise protocol for this investigation did not allow for a comparison to a reference method
The Influence of Citrus urantium and Caffeine Complex versus Placebo on the Cardiac Autonomic Response: A Double Blind Crossover Design
Background: The purpose of this study was to examine the resting cardiac autonomic nervous system’s response to the ingestion of a complex containing Citrus aurantium + Caffeine (CA + C) and its influence on recovery following a high-intensity anaerobic exercise bout in habitual caffeine users. Methods: Ten physically active males (25.1 ± 3.9 years; weight 78.71 ± 9.53 kg; height 177.2 ± 4.6 cm; body fat 15.5 ± 3.13%) participated in this study, which consisted of two exhaustive exercise protocols in a randomized crossover design. On each visit the participants consumed either a CA + C (100 mg of CA and 100 mg of C) or placebo (dextrose) capsule. After consumption, participants were monitored throughout a 45-min ingestion period, then completed a repeated Wingate protocol, and were then monitored throughout a 45-min recovery period. Cardiac autonomic function (Heart Rate (HR) and Heart Rate Variability (HRV)) and plasma epinephrine (E) and norepinephrine(NE) were taken at four different time points; Ingestion period: baseline (I1), post-ingestion period (I2); Recovery period: immediately post-exercise (R1), post-recovery period (R2). Heart rate variability was assessed in 5-min increments. Results: A repeated measures ANOVA revealed significant time-dependent increases in HR, sympathetic relatedmarkers of HRV, and plasma E and NE at I2 only in the CA + C trial (p\u3c 0.05); however, no meaningful changes in parasympathetic markers of HRV were observed. Participants recovered in a similar time-dependent manner in all markers of HRV and catecholamines following the PLA and CA + C trials. Conclusion: The consumption of CA + C results in an increase of sympathetic activity during resting conditions without influencing parasympathetic activity. CA + C provides no influence over cardiac autonomic recovery
A Comparison of Anaerobic Power Tests using Cycle Ergometry and Non-motorized Treadmill Ergometry at Optimized Loads
International Journal of Exercise Science 16(4): 1293-1305, 2023. The purpose of this study was to compare performance markers derived from a 30-second maximal bout on a cycle ergometer (CE) and non-motorized treadmill (NMT) under optimized loads. Recreationally active participants (n = 40) volunteered for the study. Force-velocity tests on the CE and NMT were used to determine optimal resistance for peak power (PP) production. The remaining visits were randomized and counterbalanced, with a single 30-second maximal test on CE or NMT to assess PP, mean power (MP), fatigue index (FI), over the course of the 30-second test, and maximum heart rate (HRmax) and blood lactate (BLa-) taken 1-minute post. Results were that PP and MP were higher (P\u3c0.05) on CE compared to NMT for both sexes. FI did not differ among males (P=0.201) whereas females showed higher FI (P=0.002) on the CE. HRmax and BLa- were higher (P\u3c0.05) after NMT for both sexes. There was no difference for optimal braking force on NMT between males (16.65±4.49%BW) and females (14.30±3.10%BW) (P=0.061). CE optimal torque factor was higher for males (0.78±0.16 Nm/kg) compared to females (0.62±0.14 Nm/kg) (P=0.001). Overall, CE produced higher power output using optimized loads in recreationally active males and females, while NMT test resulted in a higher HRmax andBLa- concentration. These tests for anaerobic power, when performed with optimized loads, produced different results for several variables, therefore these modalities should not be considered interchangeable. Practitioners should consider which modality best mimics the activities of the person being tested when selecting a protocol
Carbohydrate Rinse Fails to Enhance Cycling Performance or Alter Metabolic and Autonomic Recovery in Recreational Cyclists
The purpose of the study was to examine the effects of carbohydrate (CHO) mouth rinsing on autonomic and metabolic recovery as well as cycling performance. Ten male recreational cyclists (age = 30 ± 6 years, VO2peak = 54.5 ± 8.1 mL·kg-1·min-1) completed a randomized, double-blind, placebo-controlled, crossover designed study. A CHO or a placebo (PLA) rinse was administered every 12.5% of a work to completion trial (75%Wmax). Heart rate variability (lnRMSSD), the respiratory exchange ratio, and plasma epinephrine, norepinephrine, insulin, glucose, free fatty acids (FFA), and lactate were measured pre- and post-exercise. The CHO rinse did not improve time to completion of the test trial (CHO: 4108 ± 307 s, PLA: 4176 ± 374 s, p = 0.545). Further, the CHO rinse did not impact autonomic recovery, as measured by lnRMSSD (p = 0.787) and epinephrine (p = 0.132). Metabolic biomarkers were also unaffected by the CHO rinse, with no differences observed in responses of FFA (p = 0.064), lactate (p = 0.302), glucose (p = 0.113) or insulin (p = 0.408). Therefore, the CHO mouth rinse does not reduce the acute sympathetic response following strenuous exercise and does not result in improvements in cycling time to completion
Level of agreement between objectively determined body composition and perceived body image in 6- To 8-year-old South African children- To Body Composition-Isotope Technique study
To assess the level of agreement between body size self-perception and actual body size determined by body mass index (BMI) z-score and body fatness measured by the deuterium dilution method (DDM) in South African children aged 6-8 years. A cross-sectional sample of 202 children (83 boys and 119 girls) aged 6-8 years from the Body Composition-Isotope Technique study (BC-IT) was taken. Subjective measures of body image (silhouettes) were compared with the objective measures of BMI z-score and body fatness measured by the DDM. The World Health Organization BMI z-scores were used to classify the children as underweight, normal, overweight, or obese. DDM-measured fatness was classified based on the McCarthy centile curves set at 2nd, 85th and 95th in conjunction with fatness cut-off points of 25% in boys and 30% in girls. Data were analyzed using SPSS v26. Of 202 children, 32.2%, 55.1%, 8.8%, and 2.4% perceived their body size as underweight, normal, overweight, and obese, respectively. Based on BMI z-score, 18.8%, 72.8%, 6.9%, and 1.5% were classified as underweight, normal, overweight, and obese, respectively. Body fatness measurement showed that 2.5%, 48.0%, 21.8%, and 29.7% were underweight, normal weight, overweight, and obese, respectively
An Investigation of the Differences between Perceived vs. Measured Body Composition, Social Physique Anxiety, and Overall Appearance Satisfaction among College Students
International Journal of Exercise Science 11(5): 957-967, 2018. The purpose of this study was to examine the differences between body composition, social physique anxiety (SPA) and appearance satisfaction among college students by sex and BMI. A secondary purpose was to assess levels of appearance satisfaction before and after body composition testing and discover any differences between perceived body fat percentage (BF%) and weight versus actual measurements.Participants included 212 college students (93 males, 119 females), 22.0 ± 2.2 years. They answered a demographic questionnaire, the Social Physique Anxiety Scale (SPAS), post-assessment questions, and underwent body composition testing via dual energy x-ray absorptiometry (DXA). There was a significant correlation between measured BF% and SPAS scores (r = 0.531, P\u3c 0.001). Males scored lower on the SPAS compared to females (25.3 ± 9.4 vs. 33.1 ± 9.1, P\u3c 0.001). The sample underestimated BF% with females underestimating by more than males, 5.7 ± 7.3% vs. 3.7 ± 5.4%, P= 0.036. There was no difference between perceived and measured weight for women (P= 0.500) however, males overestimated their weight (P= 0.004). There was a difference in appearance satisfaction pre and post body composition for females (pre = 4.4 ±1.7, post = 4.2 ±1.9, P= 0.026) but not for males (pre = 5.3 ±1.5, post = 5.0 ±1.8, P= 0.063). Overall, males had lower levels of SPA and higher levels of appearance satisfaction than females and knowledge of BF% negatively affected appearance satisfaction scores for females. Finally, both males and females underestimated BF% compared to DXA
An Investigation of the Relationship Between Body Composition, Social Physique Anxiety, and Exercise Motives: 2532 Board #55 June 3, 11: 00 AM - 12: 30 PM
PURPOSE: Investigate the relationship between body composition, exercise motivations, social physique anxiety (SPA), exercise confidence, and exercise stage of change (SOC) among adults across the age span. METHODS: 192 participants (males = 89, females = 103) completed a demographic questionnaire, the Stages of Change for Exercise—Short Form, Social Physique Anxiety Scale, Exercise Confidence Survey, and Exercise Motivations Inventory-2, and body composition via DEXA. RESULTS: One-way ANOVA revealed that males were more motivated by social recognition (p = 0.003), affiliation (p = 0.029), and competition (p \u3c 0.001); females were more motivated by weight management (p = 0.050) and appearance (p \u3c 0.001). Males also had lower SPA (28.20 ± 9.71 vs. 35.25 ± 10.87) (p \u3c 0.001), higher exercise confidence (24.91 ± 13.31 vs. 30.42 ± 17.32) (p = 0.016), and were more likely to be maintainers for SOC (p = 0.006). Age was correlated to weight management (r = 0.305, p \u3c 0.001), ill-health avoidance (r = 0.271, p \u3c 0.001), social recognition (r = -0.258, p \u3c 0.001), health pressures (r = 0.219, p = 0.002), nimbleness (r = 0.204, p = 0.004), challenge (r = -0.232, p = 0.001), and appearance (r = 0.172, p = 0.017). %BF was correlated to weight management (r = 0.495, p \u3c 0.001), enjoyment (r = -0.427, p \u3c 0.001), competition (r = -0.374, p \u3c 0.001), revitalization (r = -0.351, p \u3c 0.001), social recognition (r = -0.303, p \u3c 0.001), challenge (r = -0.280, p \u3c 0.001), stress management (r = -0.274, p = 0.001), affiliation (r = -0.159, p = 0.027), and ill-health avoidance (r = 0.153, p = 0.034). CONCLUSIONS: While exercise motivations changed and %BF increased with age, overall males had different exercise motivations, lower SPA, lower %BF, higher exercise confidence, and were more likely to be maintainers than females, regardless of age
A Comparison of Standing vs. Seated Cycle Ergometer Graded Exercise Test Protocols: 402 Board #239 June 1, 11: 00 AM - 12: 30 PM
PURPOSE: To investigate if allowing participants to stand at the end of a ramp protocol CE GXT would elicit a VO2 max closer to a TM GXT compared to remaining seated. METHODS: A sample of healthy low risk participants (male = 14, female = 9) aged 26.2 ± 7.1 y completed body composition testing, a TM GXT, a seated ramp CE GXT (seat-CE), and a seated-to-standing ramp CE GXT (stand-CE) over 3 visits. Participants could stand once they reached an RPE of 15 on the Borg scale. The order of these tests was randomized and completed within 2 weeks of the initial visit. RESULTS: For males, TM VO2 max (49.3 ± 7.2 mL/kg/min) was higher than seat-CE (44.6 ± 8.1 mL/kg/min) (p \u3c 0.001), and stand-CE (45.6 ± 8.8 mL/kg/min) (p \u3c 0.001), with a difference between seat-CE and stand-CE (p = 0.047). The average time spent standing during stand-CE in males was 100.4 ± 54.4 seconds. For females, TM VO2 max (43.0 ± 5.7 mL/kg/min) was higher than seat-CE (39.6 ± 4.1 mL/kg/min) (p = 0.024), and stand-CE (39.4 ± 5.0 mL/kg/min) (p = 0.005) with no difference between seat-CE and stand-CE (p = 0.880). The average time spent standing during stand-CE in females was 66.0 ± 31.1 seconds. CONCLUSIONS: Though there was not a significant difference between seat-CE and stand-CE VO2 max in females, there was a difference in males. The results of this investigation suggest that allowing participants to stand at the end of a CE GXT will not affect VO2 max values for a ramp protocol in females and may actually produce values closer to those from a TM GXT in males. Based on these data further investigation is warranted to determine if standing at the end of a ramp protocol significantly affects results for healthy males
Agreement Between 2 Segmental Bioimpedance Devices, BOD POD, and DXA in Obese Adults
This study examined the agreement between 2 segmental bioimpedance analysis (BIA) devices, air displacement plethysmography (BOD POD), and dual energy X-ray absorptiometry (DXA) for estimating body composition in obese adults. Fifty obese adults (25 men and 25 women; age = 34.20 ± 11.19 years; BMI = 36.14 ± 5.33 kg/m2) had their body fat percentage (BF%) and fat-free mass (FFM) evaluated with 2 segmental BIA devices (InBody 230 and InBody 720), BOD POD, and DXA (Lunar iDXA). Body composition via the BOD POD was determined using the Siri equation whereas manufacturer-based equations generated metrics (ie, BF% and FFM) for the InBody devices. The effect size of the mean differences for all BF% and FFM comparisons were trivial (Cohen\u27s d \u3c 0.20). The standard error of estimate (SEE), total error (TE), and 95% limits of agreement (LOAs) were low for both segmental BIA devices when compared to DXA (SEE \u3c 2.26% and 2.35 kg; TE \u3c 2.58% and 2.66 kg; 95% LOAs \u3c ± 4.94% and 4.86kg). The error for BOD POD was also low when compared to DXA (SEE = 2.39% and 2.57 kg; TE = 2.34% and 2.56 kg; 95% LOAs = 4.63% and 5.06 kg). Validity statistics were slightly higher, but considered acceptable, when comparing the segmental BIA devices against BOD POD (SEE \u3c 3.37% and 3.63 kg; TE \u3c 3.44% and 3.79 kg; 95% LOAs \u3c ± 6.62% and 7.19 kg). Lastly, the 2 segmental BIA devices produced nearly identical validity statistics when compared to each other. However, both BIA devices revealed proportional bias for BF% and FFM when compared to the BOD POD and DXA (all p \u3c 0.05). The current study\u27s findings indicate the InBody 230 is interchangeable with the InBody 720 in obese adults. Also, the trivial effect size, when compared against the BOD POD and DXA, suggest the InBody devices could be used for estimating group BF% and FFM. In contrast, the significant proportional bias demonstrates the BIA devices are not acceptable for individual estimates of body composition in an obese clinical population