Comparative analysis of BIA, IBC and DXA for determining body fat in American Football players.

BACKGROUND: Body composition is frequently measured by sports, fitness, and healthcare professionals. Dual-Energy X-ray Absorptiometry (DXA) analysis is a validated measurement of body composition and is considered a criterion or "gold-standard" measurement. However, due to long scan times, accessibility and cost, conducting DXA scans on larger athletes (i.e., football players) is difficult. Hence fitness professionals, notably strength and conditioning coaches, typically use other methods to measure body composition. The aim of this study was to assess the accuracy of the Bioelectrical Impedance Analysis (BIA) and Integrative Body Composition (IBC) techniques to DXA body fat percent (BF%) in collegiate American Football players. METHODS: Participants performed all three modes of body composition measurement: DXA, BIA (BIA-A [athlete]and BIA-NA [non-athlete modes]), and IBC, on the same day during early morning hours in a fasted state. RESULTS: The BF% measured via all methods significantly correlated with BF% measured via DXA (i.e., BIA-A [P<0.001, r=0.903], BIA-NA [P<0.001, r=0.891], and IBC [P<0.001, r=0.867]). However, values obtained via BIA-A (athlete) (P<0.001) and IBC (P<0.001) methods under predicted BF%. CONCLUSIONS: BIA and IBC can be used as an alternative to DXA for measuring BF% in American Football players. The BIA-A and IBC under predicted BF% compare to DXA, therefore, a correction formula can be utilized by coaches and athletes to predict BF% more accurately compared to IBC and BIA-A methods in American Football players.

Comparison of Myoelectric Activity During a Suspension-Based and Traditional Split Squat.

Miller, WM, Barnes, JT, Sofo, SS, and Wagganer, JD. Comparison of myoelectric activity during a suspension-based and traditional split squat. J Strength Cond Res 33(12): 3236-3241, 2019-Over several decades, traditional resistance training has incorporated body-mass suspension training (SPT), for example, Total-Body Resistance Exercise (TRX); however, very little research has been completed investigating the effects of lower body SPT. Therefore, the purpose of this study was to assess sex differences in myoelectric activity via electromyography while performing a stable (i.e., bench) traditional split squat (TSS) compared with suspension body-mass split squat (TRXSS). Nineteen recreationally active individuals (mean ± SD = men: n = 9; 21.4 ± 2.1 years; 177.2 ± 9.0 cm; 84.2 ± 8.8 kg; women: n = 10; 21.5 ± 1.6 years; 160.7 ± 8.5 cm; 59.1 ± 7.9 kg) participated in this investigation. Subjects performed 3 training sessions, 1 familiarization and 2 (one for each variation) split squat. The TRXSS was performed by placing the rear foot within the foot cradle of the strap, while the TSS required placement of the rear foot on a stable bench (40.64 cm). The TRXSS resulted in higher peak and average myoelectric activity overall, as well as greater gluteus maximus myoelectric activity. No gender or rectus femoris myoelectric activity differences were found. The increased myoelectric activity of the gluteus maximus during the TRXSS was most likely due to increased medial/lateral stabilization demands on the suspended leg. These findings provide insight into TRX as a useful exercise modality for recreationally active or rehabilitative purposes.

Traditional Versus Suspended Push-up Muscle Activation in Athletes and Sedentary Women.

Syed-Abdul, MM, Soni, DS, Miller, WM, Johnson, RJ, Barnes, JT, Pujol, TJ, and Wagganer, JD. Traditional versus suspended push-up muscle activation in athletes and sedentary women. J Strength Cond Res 32(7): 1816-1820, 2018-Many strength training programs incorporate push-up exercises, which primarily activate upper-body muscles. Past data support the fact that shoulder girdle muscles (i.e., triceps (T) and anterior deltoids [AD]) exhibit greater electromyography (EMG) activity when a push-up is performed on an unstable (i.e., suspended [SP]) vs. stable (i.e., traditional [TD]) surface (). Sixty-nine healthy female volunteers (soccer players [SO], n = 24; gymnasts [GY], n = 21; sedentary [SE], n = 24) performed three TD and three SP push-ups. Muscle activation, expressed as absolute integral (mV), was measured using EMG analysis. Significant increases in muscle activation were exhibited by GY (TD: p < 0.01 and SP: p < 0.001) and SO (TD: p < 0.05 and SP: p < 0.05) compared to SE for the T muscle. Only SO (p < 0.05) exhibited significantly higher muscle activation during the SP versus TD. For the AD, values were significantly higher for SO (TD: p < 0.001 and SP: p < 0.001) and GY (TD: p < 0.01 and SP: p < 0.01) compared to the SE group. In addition, significantly higher values were exhibited by SO compared with GY during TD push-ups (p < 0.01). Both the SO (p < 0.05) and GY (p < 0.05) group exhibited significantly higher values during SP versus TD push-ups. Finally, values were significantly higher for the AD compared to the T muscle only in the SO group during TD (p < 0.01) and SP (p < 0.05) push-ups. Data from this study for trained women (i.e., SO) are consistent with previous studies, whereas for untrained women (i.e., SE) the findings differed during TD and SP push-ups for both muscles. Differences were also observed between female SO and GY are unexplainable and therefore need further investigation.

A WORKLOAD SELECTION PROCEDURE FOR THE ÅSTRAND-RYHMING TEST FOR WOMEN.

UNLABELLED: The Åstrand-Ryhming Submaximal Bicycle Test is an accurate and widely used test to estimate maximal oxygen consumption. This test requires a participant to maintain a workload over a 6-min. PERIOD: The issue facing many employing this protocol is the identification of an appropriate workload for the cycling regimen. The present study is designed to identify a method for determining an appropriate workload for female participants. A prior study designed a workload selection procedure specifically for men; however, the selection procedure designed for women in this study was better able to elicit a final heart rate (average of minutes five and six) between 165-170 bpm compared to the original Åstrand-Ryhming procedure.

Effects of exercise accumulation on plasma lipids and lipoproteins.

Debate exists as to whether improvements in some cardiometabolic risk factors following exercise training result more from the last session of, or from an accumulation of, exercise sessions. This study was designed to compare the effect of a single exercise session with 3 consecutive days of exercise on triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C). Twelve young adult (aged 22.5±2.5 years), overweight (body mass index=29.7±4 kg·m(-2)), sedentary, black (n=5) and white (n=7) men (n=6) and women (n=6) completed, in random order, a single treadmill exercise session at 60% maximal oxygen uptake for 90 min (1EX), accumulated exercise sessions (same as for 1EX) for 3 consecutive days (3EX), and a control protocol (no exercise for 6 days). Plasma samples were collected from baseline through 24, 48, and 72 h postexercise. Significant treatment-by-time interactions (p<0.05) existed in HDL-C and LDL-C. Postexercise responses of HDL-C differed at 48 h (1EX: -3.6, 3EX: +3.7 mg·dL(-1)) and 72 h (1EX: -1.7, 3EX: +3.2 mg·dL(-1)). LDL-C responses differed at 48 h (1EX: -16, 3EX: +6 mg·dL(-1)). Although not statistically significant, TG concentrations decreased by 29% at 24 h after 3EX, compared with -7% after 1EX. An inverse relationship between baseline and postexercise reduction in TG was present with 3EX (r=-0.655; p<0.05). In conclusion, 3EX increased HDL-C and decreased TG more than 1EX, while the decrease in LDL-C after 1EX was suppressed. Blood lipid panel changes may be due to more accumulated effects over time rather than just a result of the most recent exercise session.

Validity of a portable computer-based ultrasound system for estimating adipose tissue in female gymnasts.

The aim of this investigation was to determine the validity of a portable ultrasound instrument for estimating adipose tissue (AT%) compared to dual-energy X-ray absorptiometry (DXA) in female collegiate gymnasts. Participants had their measurements taken in the following order: urine-specific gravity, body mass, height, ultrasound determined AT% (1-site and 3-site) and DXA determined AT%. The current pilot study found significant differences between estimates of AT% (P < 0·001). Pearson's correlations between DXA and 1-site and 3-site estimates were r = 0·786 and r = 0·753, respectively. The standard error of the estimate between DXA and 1-site and 3-site estimates was 3·6% and 3·9%, respectively. However, the average deviation of individual scores from the line of identity was 6·7% for the 1-site and 4·9% for the 3-site, when compared with the DXA estimate. The results of this preliminary study found that the portable ultrasound was not a valid estimate of AT% when compared with the DXA estimate in female collegiate gymnasts.

Validity and reliability of an ultrasound system for estimating adipose tissue.

When health professionals measure the fitness levels of clients, body composition is usually estimated. In field settings, body composition is commonly estimated with skinfolds or bioelectrical impedance analysis. Recently, a portable ultrasound device has been manufactured to estimate what percentage of body mass is composed of adipose tissue (AT%). A reported advantage of using ultrasound is that inter- and intrarater variations may be minimized when compared with the skinfold technique. Therefore, the purpose of this pilot study was twofold; 1) to determine the validity of a portable ultrasound device compared with skinfolds and 2) determine the reliability of the portable ultrasound device. Participants had their measurements taken in the following order: urine specific gravity, body mass, height, skinfolds and ultrasound determined. Participants had their urine specific gravity and ultrasound determined AT% estimates measured again 48 h later. The current pilot study found that the ultrasound was not a valid estimate of AT% when compared with the skinfold estimate (TE > 4%). In addition, the 1-site estimate from the ultrasound was more reliable than the 3-site estimate of AT%. These data are of importance to practitioners because it demonstrates that while the ultrasound is not a valid estimate compared with skinfolds, the 1-site estimate may be able to track changes in AT% over time, making the ultrasound an option for assessing changes in body composition.