Physical determinants of Division 1 Collegiate basketball, Women’s National Basketball League and Women’s National Basketball Association athletes: with reference to lower body sidedness

In female basketball the assumed components of success include power, agility, and the proficiency at executing movements using each limb. However, the importance of these attributes in discriminating between playing levels in female basketball have yet to be determined. The purpose of this study was to compare lower body power, change of direction (COD) speed, agility, and lower-body sidedness between basketball athletes participating in Division 1 Collegiate basketball (United States), Women\u27s National Basketball League (WNBL) (Australia), and Women\u27s National Basketball Association (WNBA) (United States). Fifteen female athletes from each league (N = 45) completed a double and single leg counter-movement jump, static jump, drop jump, 5-0-5 COD Test, and an offensive and defensive Agility Test. One-way analysis of variance with post-hoc comparisons, were conducted to compare differences in physical characteristics (height, body mass, age) and performance outcomes (jump, COD, agility assessments) between playing levels. Separate dependent t-tests were performed to compare lower body sidedness (left vs. right lower-limbs) during the single-leg CMJ jumps (vertical jump height) and 5-0-5 COD test for each limb within each playing level. WNBA athletes displayed significantly greater lower body power (P = 0.01 - 0.03) compared to WNBL athletes, significantly faster COD speed (P = 0.02 - 0.03), and offensive and defensive agility performance (P = 0.02 - 0.03) compared to WNBL and Collegiate athletes. WNBL athletes also produced faster defensive agility performance compared to Collegiate athletes (P = 0.02). Further, WNBA and WNBL athletes exhibited reduced lower body sidedness compared to Collegiate athletes. These findings indicate the importance of lower body power, agility, and reduced lower body imbalances to execute more proficient on court movements, required to compete at higher playing levels. Copyright (C) 2017 by the National Strength & Conditioning Association

Acute effects of ingesting a commercial thermogenic drink on changes in energy expenditure and markers of lipolysis

Background: To determine the acute effects of ingesting a thermogenic drink (Celsius, Delray Beach, FL) (TD) on changes in metabolism and lipolysis. Methods: Healthy college-aged male (23.2 ± 4.0 y, 177.2 ± 6.1 cm, 81.7 ± 11.3 kg, 22.8 ± 7.3 % fat; n = 30) and female (23.4 ± 3.1 y, 165.6 ± 8.7 cm, 62.1 ± 9.9 kg, 28.3 ± 7.4 % fat; n = 30) participants were matched according to height and weight to consume 336 ml of the TD or a noncaloric, non-caffeinated placebo (PLA). After a 12 h fast, participants reported for pre-consumption measures of height, weight, heart rate, blood pressure, resting energy expenditure (REE), respiratory exchange ratio (RER), glycerol and free-fatty acid (FFA) concentrations. REE and RER were determined at 60, 120, and 180 min post-consumption. Serum glycerol and FFA concentrations were determined at 30, 60, 120 and 180 min post-consumption. Results: When compared to PLA, TD significantly increased REE at 60, 120 and 180 min (p < 0.05). FFA concentrations were significantly greater in TD compared to PLA at 30, 60, 120 and 180 min post-consumption (p < 0.05). No between-group differences were found in RER. Conclusion: Acute TD ingestion significantly increased REE, FFA and glycerol appearance. If sustained, these changes may help to promote weight loss and improve body composition; however, these findings are currently unknown as are the general safety and efficacy of prolonged consumption

Efficacy and safety of a popular thermogenic drink after 28 days of ingestion

Background: We have recently demonstrated that consuming a thermogenic drink (TD) acutely increases energy expenditure and serum markers of lipolysis in healthy, college-aged individuals. The purpose of this study was to determine if consuming TD over 28 days affects its acute thermogenic and lipolytic effects as well as body composition and clinical chemistry safety markers. Methods: Sixty healthy, males (mean ± SE; 23 ± 1 years, 177 ± 2 cm, 81.7 ± 2.1 kg, 22.8 ± 1.4% body fat; n = 30) and females (23 ± 1 years, 166 ± 2 cm, 62.1 ± 1.8 kg, 28.3 ± 1.4% body fat; n = 30) reported to the laboratory on day 0 (T1) for determination of body composition, resting energy expenditure (REE) as well as glycerol and free fatty acid (FFA) levels before and after ingesting either 336 ml of TD or a non-caloric, non-caffeinated placebo (PLA) drink. Following day 0, participants supplemented daily with 336 ml•day-1 of either TD or PLA and repeated identical testing procedures on day 28 (T2). Day 28 area under the curve (AUC) values were calculated for REE, FFA, and glycerol. Day 28 acute data and prolonged AUC comparisons between groups were analyzed using ANOVAs with repeated measures. Results: Percent body fat (p = 0.02) and fat mass (p = 0.01) decreased in the TD group compared to the PLA group after 28 days. Day 28 FFA AUC values (p = 0.048) were greater in the TD group compared to the PLA group. There was no significant difference in day 28 REE AUC values (p = 0.30) or glycerol AUC values (p = 0.21), although a significant increase in REE values in the PLA group may have confounded these findings. There were no differences between groups concerning blood and clinical safety markers. Conclusion: Within-group elevations in FFA and REE values in the TD group were still evident following a 28-day supplementation period which may contribute to the observed decrements in %BF. Further, prolonged TD supplementation did not alter the assessed clinical safety markers. Future studies should examine the synergistic and independent effects of the active ingredients in addition to effects of longer ingestion periods of TD ingestion with or without exercise at promoting and sustaining changes in body composition

The effects of age on skeletal muscle and the phosphocreatine energy system: can creatine supplementation help older adults

Creatine supplementation has been found to significantly increase muscle strength and hypertrophy in young adults (≤ 35 yr) particularly when consumed in conjunction with a resistance training regime. Literature examining the efficacy of creatine supplementation in older adults (55-82 yr) suggests creatine to promote muscle strength and hypertrophy to a greater extent than resistance training alone. The following is a review of literature reporting on the effects of creatine supplementation on intramuscular high energy phosphates, skeletal muscle morphology and quality of life in older adults. Results suggest creatine supplementation to be a safe, inexpensive and effective nutritional intervention, particularly when consumed in conjunction with a resistance training regime, for slowing the rate of muscle wasting that is associated with aging. Physicians should strongly consider advising older adults to supplement with creatine and to begin a resistance training regime in an effort to enhance skeletal muscle strength and hypertrophy, resulting in enhanced quality of life

Within Game and Between Gender Comparisons of Match Demands in Men’s and Women’s International Touch Rugby World Cup

Touch rugby is an intermittent, high-intensity, anaerobic team sport that is widely played internationally as the Federation of International Touch includes 47-member nations. PURPOSE: The present study quantified and compared the match demands of men’s and women’s international touch rugby players during the 2019 world cup. METHODS: Match demands (male: n=16; female: n=15) were assessed via 5Hz global positioning system devices. Separate linear mixed models and Cohen’s effect size comparisons were used to compare variables within matches (1st v 2nd half) for men’s and women’s only matches, while between gender comparisons were made for complete match demands. RESULTS: Within match comparisons revealed significant, small reductions in running distance (p = 0.003) and one-minute peak average speed (p = 0.019) for men’s matches in the second half compared to the first half. For women’s matches a significant, small reduction in running distance (p \u3c0.001) and a significant, small increase for walking distance (p \u3c0.001) was revealed during the second half compared to the first half. Significant, small to moderate differences were found between men’s and women’s matches for average speed (p = 0.006), running distance (p \u3c0.001), sprint distance (p \u3c0.001), and peak speed (p \u3c0.001). CONCLUSION: Findings show the physical demands of men’s touch rugby matches are more demanding than women’s matches. Results from our study suggest that gender specific conditioning programs should be implemented to ensure suitable preparation for international matches

Minimal nutrition intervention with high-protein/low-carbohydrate and low-fat, nutrient-dense food supplement improves body composition and exercise benefits in overweight adults: A randomized controlled trial

Background: Exercise and high-protein/reduced-carbohydrate and -fat diets have each been shown separately, or in combination with an energy-restricted diet to improve body composition and health in sedentary, overweight (BMI > 25) adults. The current study, instead, examined the physiological response to 10 weeks of combined aerobic and resistance exercise (EX) versus exercise + minimal nutrition intervention designed to alter the macronutrient profile, in the absence of energy restriction, using a commercially available high-protein/low-carbohydrate and low-fat, nutrient-dense food supplement (EXFS); versus control (CON). Methods: Thirty-eight previously sedentary, overweight subjects (female = 19; male = 19) were randomly assigned to either CON (n = 10), EX (n = 14) or EXFS (n = 14). EX and EXFS participated in supervised resistance and endurance training (2× and 3×/wk, respectively); EXFS consumed 1 shake/d (weeks 1 and 2) and 2 shakes/d (weeks 3–10). Results: EXFS significantly decreased total energy, carbohydrate and fat intake (-14.4%, -27.2% and -26.7%, respectively; p < 0.017), and increased protein and fiber intake (+52.1% and +21.2%, respectively; p < 0.017). EX and EXFS significantly decreased fat mass (-4.6% and -9.3%, respectively; p < 0.017), with a greater (p < 0.05) decrease in EXFS than EX and CON. Muscle mass increase only reached significance in EXFS (+2.3%; p < 0.017), which was greater (p < 0.05) than CON but not EX (+1.1%). Relative VO2max improved in both exercise groups (EX = +5.0% and EXFS = +7.9%; p < 0.017); however, only EXFS significantly improved absolute VO2max (+6.2%; p = 0.001). Time-to-exhaustion during treadmill testing increased in EX (+9.8%) but was significantly less (p < 0.05) than in EXFS (+21.2%). Total cholesterol and LDL decreased only in the EXFS (-12.0% and -13.3%, respectively; p < 0.017). Total cholesterol-to-HDL ratio, however, decreased significantly (p < 0.017) in both exercise groups. Conclusion: Absent energy restriction or other dietary controls, provision of a high-protein/low-carbohydrate and -fat, nutrient-dense food supplement significantly, 1) modified ad libitum macronutrient and energy intake (behavior effect), 2) improved physiological adaptations to exercise (metabolic advantage), and 3) reduced the variability of individual responses for fat mass, muscle mass and time-to-exhaustion – all three variables improving in 100% of EXFS subjects

Total body water estimations in healthy men and women using bioimpedance spectroscopy: a deuterium oxide comparison

<p>Abstract</p> <p>Background</p> <p>Total body water (TBW) estimations have been used to estimate body composition, particularly fat-free mass, to aid in nutritional interventions, and to monitor hydration status. In the past, bioimpedance spectroscopy (BIS) devices have been used to estimate TBW. Previous investigations have examined the validity of the XiTRON 4000B (XiTRON Technologies) BIS device for estimating TBW. Recently, a new BIS device (Imp™ SFB7) has become available, claiming greater precision when estimating TBW. The Imp™ SFB7 (SFB7) is based on similar BIS principles, while offering increased portability and a greater range of frequencies when compared to older devices, such as the XiTRON 4000B (4000B). The purpose of this study was to examine the validity of the SFB7 for estimating total body water in healthy college-age men and women compared to the 4000B and deuterium oxide (D₂O).</p> <p>Methods</p> <p>Twenty-eight Caucasian men and women (14 men, 14 women; 24 ± 4 yrs; 174.6 ± 8.7 cm; 72.80 ± 17.58 kg) had their TBW estimated by the SFB7, the 4000B, and D₂O.</p> <p>Results</p> <p>Both BIS devices produced similar standard error of estimate (<it>SEE</it>) and <it>r </it>values (SFB7, <it>SEE </it>= 2.12L, <it>r </it>= 0.98; 4000B, <it>SEE </it>= 2.99L, <it>r </it>= 0.96) when compared to D₂O, though a significant constant error (<it>CE</it>) was detected for the 4000B (2.26L, <it>p </it>≤ 0.025). The 4000B produced a larger total error (<it>TE</it>) and <it>CE </it>(<it>TE </it>= 3.81L, <it>CE </it>= 2.26L) when compared to the SFB7 (<it>TE </it>= 2.21L, <it>CE </it>= -0.09L). Additionally, the limits of agreement were larger for the 4000B (-3.88 to 8.39L) than the SFB7 (-4.50 to 4.31L). These results were consistent when sex was analyzed separately, though women produced lower <it>SEE </it>and <it>TE </it>values for both devices.</p> <p>Conclusion</p> <p>The 4000B and SFB7 are valid BIS devices when compared to D₂O to estimate TBW in college-age Caucasian men and women. Furthermore, the new SFB7 device displayed greater precision in comparison to the 4000B, which may decrease the error when estimating TBW on an individual basis.</p

Percent body fat estimations in college men using field and laboratory methods: A three-compartment model approach

Background: Methods used to estimate percent body fat can be classified as a laboratory or field technique. However, the validity of these methods compared to multiple-compartment models has not been fully established. The purpose of this study was to determine the validity of field and laboratory methods for estimating percent fat (%fat) in healthy college-age men compared to the Siri three-compartment model (3C). Methods: Thirty-one Caucasian men (22.5 ± 2.7 yrs; 175.6 ± 6.3 cm; 76.4 ± 10.3 kg) had their %fat estimated by bioelectrical impedance analysis (BIA) using the BodyGram™ computer program (BIA-AK) and population-specific equation (BIA-Lohman), near-infrared interactance (NIR) (Futrex® 6100/XL), four circumference-based military equations [Marine Corps (MC), Navy and Air Force (NAF), Army (A), and Friedl], air-displacement plethysmography (BP), and hydrostatic weighing (HW). Results: All circumference-based military equations (MC = 4.7% fat, NAF = 5.2% fat, A = 4.7% fat, Friedl = 4.7% fat) along with NIR (NIR = 5.1% fat) produced an unacceptable total error (TE). Both laboratory methods produced acceptable TE values (HW = 2.5% fat; BP = 2.7% fat). The BIA-AK, and BIA-Lohman field methods produced acceptable TE values (2.1% fat). A significant difference was observed for the MC and NAF equations compared to both the 3C model and HW (p < 0.006). Conclusion: Results indicate that the BP and HW are valid laboratory methods when compared to the 3C model to estimate %fat in college-age Caucasian men. When the use of a laboratory method is not feasible, BIA-AK, and BIA-Lohman are acceptable field methods to estimate %fat in this population

Tensile energy dissipation and mechanical properties of the knee meniscus: relationship with fiber orientation, tissue layer, and water content

Introduction: The knee meniscus distributes and dampens mechanical loads. It is composed of water (∼70%) and a porous fibrous matrix (∼30%) with a central core that is reinforced by circumferential collagen fibers enclosed by mesh-like superficial tibial and femoral layers. Daily loading activities produce mechanical tensile loads which are transferred through and dissipated by the meniscus. Therefore, the objective of this study was to measure how tensile mechanical properties and extent of energy dissipation vary by tension direction, meniscal layer, and water content.Methods: The central regions of porcine meniscal pairs (n = 8) were cut into tensile samples (4.7 mm length, 2.1 mm width, and 0.356 mm thickness) from core, femoral and tibial components. Core samples were prepared parallel (circumferential) and perpendicular (radial) to the fibers. Tensile testing consisted of frequency sweeps (0.01–1Hz) followed by quasi-static loading to failure. Dynamic testing yielded energy dissipation (ED), complex modulus (E*), and phase shift (δ) while quasi-static tests yielded Young’s Modulus (E), ultimate tensile strength (UTS), and strain at UTS (εUTS). To investigate how ED is influenced by the specific mechanical parameters, linear regressions were performed. Correlations between sample water content (φw) and mechanical properties were investigated. A total of 64 samples were evaluated.Results: Dynamic tests showed that increasing loading frequency significantly reduced ED (p &lt; 0.05). Circumferential samples had higher ED, E*, E, and UTS than radial ones (p &lt; 0.001). Stiffness was highly correlated with ED (R2 &gt; 0.75, p &lt; 0.01). No differences were found between superficial and circumferential core layers. ED, E*, E, and UTS trended negatively with φw (p &lt; 0.05).Discussion: Energy dissipation, stiffness, and strength are highly dependent on loading direction. A significant amount of energy dissipation may be associated with time-dependent reorganization of matrix fibers. This is the first study to analyze the tensile dynamic properties and energy dissipation of the meniscus surface layers. Results provide new insights on the mechanics and function of meniscal tissue

Inhibition of Myostatin Signaling through Notch Activation following Acute Resistance Exercise

Myostatin is a TGFb family member and negative regulator of muscle size. Due to the complexity of the molecular pathway between myostatin mRNA/protein and changes in transcription, it has been difficult to understand whether myostatin plays a role in resistance exercise-induced skeletal muscle hypertrophy. To circumvent this problem, we determined the expression of a unique myostatin target gene, Mighty, following resistance exercise. Mighty mRNA increased by 6 h (82.9624.21%) and remained high out to 48 h (56.5619.67%) after resistance exercise. Further examination of the soleus, plantaris and tibialis anterior muscles showed that the change in Mighty mRNA at 6 h correlated with the increase in muscle size associated with this protocol (R2 = 0.9996). The increase in Mighty mRNA occurred both independent of Smad2 phosphorylation and in spite of an increase in myostatin mRNA (341.86147.14% at 3 h). The myostatin inhibitor SKI remained unchanged. However, activated Notch, another potential inhibitor of TGFb signaling, increased immediately following resistance exercise (83611.2%) and stayed elevated out to 6 h (78616.6%). Electroportion of the Notch intracellular domain into the tibialis anterior resulted in an increase in Mighty mRNA (63613.4%) that was equivalent to the canonical Notch target HES-1 (94.467.32%). These data suggest that acute resistance exercise decreases myostatin signaling through the activation of the TGFb inhibitor Notch resulting in a decrease in myostatin transcriptional activity that correlates well with muscle hypertrophy