Racial/Ethnic Disparities in US Adolescents’ Dietary Quality and Its Modification by Weight-Related Factors and Physical Activity

There are well-known disparities in the prevalence of obesity across racial-ethnic groups, although the behavioral and psychological factors driving these disparities are less well understood. Therefore, the objectives of this study were: (1) to examine differences in dietary quality by race/ethnicity and weight-related variables [body mass index (BMI), weight loss attempt, and weight dissatisfaction] and physical activity (PA) using the Health Eating Index-2015 (HEI-2015); and (2) to investigate the interactions and independent associations of race/ethnicity, weight-related variables and PA on dietary quality. Data for adolescents aged 12–19 years (n = 3373) were abstracted from the 2007–2014 National Health and Nutrition and Examination Survey and analyzed using multiple PROC SURVEYREG, adjusting for demographics and accounting for complex sampling. Analyses determined that Hispanic males had better overall HEI-2015 scores than non-Hispanic whites (48.4 ± 0.5 vs. 45.7 ± 0.6, p = 0.003) or blacks (48.4 ± 0.5 vs. 45.5 ± 0.5, p \u3c 0.001). Hispanic females also had better dietary quality than non-Hispanic whites (50.2 ± 0.4 vs. 47.5 ± 0.5, p \u3c 0.001) and blacks (50.2 ± 0.4 vs. 47.1 ± 0.5, p \u3c 0.001). Meeting the PA recommendation modified racial/ethnic differences in dietary quality for females (p = 0.011) and this was primarily driven by the associations among non-Hispanic white females (ΔR2 = 2.6%, p = 0.0004). The study identified racial/ethnic and gender differences among adolescents in factors that may promote obesity. Results may be useful for obesity prevention efforts designed to reduce health disparities in adolescents

The Relationship between Arthritis and Muscular Strength in Older Women with Symptoms of Sarcopenia

Background: Sarcopenia classification is important for prevention or intervention of sarcopenia in the elderly. However, measures used for the current sarcopenia criteria, including muscular strength, could be impacted by forms of arthritis. Thus, it is crucial to understand the impact arthritis has on sarcopenia status. Objectives: The aim was to investigate if arthritis relates to sarcopenia classification via grip strength or single chair stand in older women. A secondary aim was to assess the relationship between grip strength and upper and lower body strength in those with arthritis. Design: A cross-sectional analysis. Setting and participants: Sixty-one community-dwelling older women (71.9±4.6 years) from Rhode Island. Measurements: Sarcopenia status was classified using established working definitions. Grip strength was measured using a hand grip dynamometer, chair stands were measured via a single chair stand test, and gait speed was assessed using a four-meter walk test. A segmental multifrequency bioelectrical impedance analysis assessed body composition and arthritis status was based on self-report. Upper and lower body muscular strength were measured using a chest press and leg press one repetition maximum. Results: No associations were observed between arthritis and sarcopenia status (p=0.36) nor arthritis and upper or lower body muscular strength and grip strength. Conclusions: The results of this study may indicate that arthritis is not associated with sarcopenia status but may affect other measures of muscular strength

Comparison of Current Sarcopenia Classification Criteria in Older New England Women

Objectives: To evaluate the prevalence of sarcopenia in a sample of older, sedentary women using criteria from the European Working Group on Sarcopenia in Older People (EWGSOP), the International Working Group (IWG), and the Foundation for the National Institutes of Health Sarcopenia Project (FNIHSP). Design: Cross-sectional analysis. Setting and Participants: Community-dwelling women (n = 61) aged 71.9 ± 4.6 years (mean±SD) with a BMI 27.3 ± 6.0 kg/m2 who by self-report were healthy and did not exercise were recruited and evaluated for sarcopenia. Measurements: Height, weight, grip strength, gait speed, and appendicular lean mass (via segmental multi-frequency bioelectrical impedance analysis: SMF-BIA) were measured. Prevalence was reported using descriptive statistics and a Fisher’s exact test was used to analyze the distribution frequency of sarcopenia classification by different criteria. Results: In this sample 14.8% met EWGSOP criteria, 6.6% met FNIHSP criteria, and 3.3% met IWG criteria. There was a borderline significant difference in distribution frequency between EWGSOP and IWG classification criteria (p=0.053). Conclusion: The variation in sarcopenia prevalence depending on the diagnostic criteria used is consistent with previous research and there are borderline significant differences between classification criteria in this population. These data suggest the need for additional examination to determine current cut points for ALM measured by SMF-BIA, as well as which established definition of sarcopenia is appropriate for this population

Ergogenic effects of betaine supplementation on strength and power performance

<p>Abstract</p> <p>Background</p> <p>We investigated the ergogenic effects of betaine (B) supplementation on strength and power performance.</p> <p>Methods</p> <p>Twelve men (mean ± SD age, 21 ± 3 yr; mass, 79.1 ± 10.7 kg) with a minimum of 3 months resistance training completed two 14-day experimental trials separated by a 14-day washout period, in a balanced, randomized, double-blind, repeated measures, crossover design. Prior to and following 14 days of twice daily B or placebo (P) supplementation, subjects completed two consecutive days (D1 and D2) of a standardized high intensity strength/power resistance exercise challenge (REC). Performance included bench, squat, and jump tests.</p> <p>Results</p> <p>Following 14-days of B supplementation, D1 and D2 bench throw power (1779 ± 90 and 1788 ± 34 W, respectively) and isometric bench press force (2922 ± 297 and 2503 ± 28 N, respectively) were increased (p < 0.05) during REC compared to pre-supplementation values (1534 ± 30 and 1498 ± 29 W, respectively; 2345 ± 64 and 2423 ± 84 N, respectively) and corresponding P values (1374 ± 128 and 1523 ± 39 W; 2175 ± 92 and 2128 ± 56 N, respectively). Compared to pre-supplementation, vertical jump power and isometric squat force increased (p < 0.05) on D1 and D2 following B supplementation. However, there were no differences in jump squat power or the number of bench press or squat repetitions.</p> <p>Conclusion</p> <p>B supplementation increased power, force and maintenance of these measures in selected performance measures, and these were more apparent in the smaller upper-body muscle groups.</p

Training Responses And Adaptations Of The Endocrine System

Umbilical cord stem cells would be a favorable alternative to embryonic stem cells for therapeutic applications. In this study, human multipotent progenitor cells (MLPCs) from umbilical cord were differentiated into oligodendrocytes by being exposed to a range of microenvironmental chemical and physical cues. Chemical cues were represented by a novel defined differentiation medium containing the neurotransmitter norepinephrine (NE). Under traditional two-dimensional conditions, the MLPCs differentiated into oligodendrocyte precursors but did not progress further. However, in a three-dimensional environment, the MLPCs differentiated into committed oligodendrocytes that expressed myelin basic protein. The apparent method of interaction of NE in stimulating the differentiation process was shown to occur through the adenergic pathway, while all prior differentiation methods have used other routes. This novel method of obtaining functional human oligodendrocytes from MLPCs would eliminate many of the difficulties associated with their differentiation from embryonic stem cells. © 2011 American Chemical Society

Effects of circadian rhythm on power, force, and hormonal response in young men

Circadian rhythms (CRs) persist in many physiological systems related to performance. The effects of circadian patterns on dynamic muscular power are minimal and conflicting. Furthermore, no study to date has investigated the effect of CR on bench press throws (BPTs) despite its popularity as a modality to increase muscular power. The purpose of this study was to examine the effects of circadian variations on muscular power output and hormonal changes in men. College aged men (n 7, age: 23.6 ± 1.3 years, height: 179.9 ± 5.4 cm, and body mass: 81.5 ± 19.7 kg.) were recruited for this repeated measures study. Testing occurred at 4 different times of day (04:00, 10:00, 16:00, and 22:00 hours). Testosterone (T) and cortisol (C) hand dynamometer strength (GS), heart rate (HR), mental readiness (MR), BPT and squat jumps (SJs), power (P), and force (F) were measured at each time point. Statistical significance was set at (p ≤ 0.05). There were no significant differences in HR, MR, and GS among all time points. There were no decrements in P or F in BPT or SJ among any time point (p ≥ 0.05). Testosterone and C decreased significantly throughout the day (p ≤ 0.05). Although P and F output differed at various percentages of 1 repetition maximum, they were not affected by circadian pattern, such that muscular performance was not impaired at any time point. Practical implications of these data indicate that high force and power exercises using BPT or SJ may be performed any time of day without detrimental decreases in acute performance

National Scouting Combine Scores as Performance Predictors in the National Football League

Vincent, LM, Blissmer, BJ, and Hatfield, DL. National Scouting Combine scores as performance predictors in the National Football League. J Strength Cond Res 33(1): 104-111, 2019 - The National Football League (NFL) hosts an annual scouting combine to evaluate the approximately 300 elite college football players who are most likely to be selected in the upcoming NFL draft. Given the public interest, player obligations, coaching staff commitments, and business aspects of the combine, several questions have arose in recent years concerning the applicability of combine scores to eventual draft NFL performance. The primary purpose of this study is to investigate the relationship between specified National Scouting Combine (NSC) scores and measures of performance by player position. A secondary aim was to determine whether correlated variables could predict player performance at the quarterback (QB), running back (RB), wide receiver (WR), defensive end (DE), defensive tackle (DT), and linebacker (LB) positions. Subjects in this study were combine participants between the years 2005-2010 who subsequently played in the NFL. The positional groups investigated were QBs (N = 44), RBs (N = 82), WRs (N = 116), LBs (N = 139), DEs (N = 59), and DTs (N = 72). Combine raw scores for 40-yd dash time, countermovement vertical jump (CMVJ) height, standing long jump (SLJ) distance, and pro-agility time were recorded. Measures of horizontal and vertical power were calculated for the 40-yd dash and CMVJ. Combine scores and on-field positional statistics for the first 4 years for QBs and 3 years of all other players\u27 careers were analyzed to investigate relationships. Significant correlations were shown between at least one combine measure and on-field success at every position. Hierarchal regression showed combine measures could predict between 4% and 62% of the variance for individual on-field variables. Quarterback rushing yards were significantly correlated with 40T, CMVJ, vertical jump power (VJP), vertical jump relative power (VJRP), and horizontal power (HP), and those factors accounted for 62.2% of the total variance. Horizontal power and VJP were predictive of QB rushing attempts (r2 = 0.370). At RB, 40T and SLJ combined were predictive of total rushing yards (r2 = 0.200), rushing attempts (r2 = 0.195), and yards per game (r2 = 0.197). Power variables were predictive of total tackles for DEs\u27 40HP (r2 = 0.096) and VJP (r2 = 0.018), accounting for a total of 21% of the variance. The current study suggests that combine tests are modest predictors of future performance. Should the NFL change the current NSC testing battery, the addition of horizontal and vertical power measurements, as well as position-specific skill tests are recommended

Training responses and adaptations of the endocrine system

Umbilical cord stem cells would be a favorable alternative to embryonic stem cells for therapeutic applications. In this study, human multipotent progenitor cells (MLPCs) from umbilical cord were differentiated into oligodendrocytes by being exposed to a range of microenvironmental chemical and physical cues. Chemical cues were represented by a novel defined differentiation medium containing the neurotransmitter norepinephrine (NE). Under traditional two-dimensional conditions, the MLPCs differentiated into oligodendrocyte precursors but did not progress further. However, in a three-dimensional environment, the MLPCs differentiated into committed oligodendrocytes that expressed myelin basic protein. The apparent method of interaction of NE in stimulating the differentiation process was shown to occur through the adenergic pathway, while all prior differentiation methods have used other routes. This novel method of obtaining functional human oligodendrocytes from MLPCs would eliminate many of the difficulties associated with their differentiation from embryonic stem cells. © 2011 American Chemical Society

The effect of caffeine ingestion on delayed onset muscle soreness

The beneficial effects of caffeine on aerobic activity and resistance training performance are well documented. However, less is known concerning caffeine\u27s potential role in reducing perception of pain and soreness during exercise. In addition, there is no information regarding the effects of caffeine on delayed onset muscle soreness (DOMS). The primary purpose of this study was to examine the effect of caffeine ingestion on muscle soreness, blood enzyme activity, and performance after a bout of elbow flexion/extension exercise. Nine low-caffeine-consuming males (body mass: 76.68 6 8.13 kg; height: 179.18 6 9.35 cm; age: 20 6 1 year) were randomly assigned to ingest either caffeine or placebo 1 hour before completing 4 sets of 10 bicep curls on a preacher bench, followed by a fifth set in which subjects completed as many repetitions as possible. Soreness and soreness on palpation intensity were measured using three 0-10 visual analog scales before exercise, and 24, 48, 72, 96, and 120 hours after exercise. After a washout period, subjects crossed over to the other treatment group. Caffeine ingestion resulted in significantly (p # 0.05) lower levels of soreness on day 2 and day 3 compared with placebo. Total repetitions in the final set of exercise increased with caffeine ingestion compared with placebo. This study demonstrates that caffeine ingestion immediately before an upper-body resistance training out enhances performance. A further beneficial effect of sustained caffeine ingestion in the days after the exercise bout is an attenuation of DOMS. This decreased perception of soreness in the days after a strenuous resistance training workout may allow individuals to increase the number of training sessions in a given time period. © 2013 National Strength and Conditioning Association

Thyroid hormones and commonly cited symptoms of overtraining in collegiate female endurance runners

Purpose: Overtraining syndrome (OTS) is reported in endurance sports. Thyroid hormones (TH) regulate metabolism, mood, and energy production, and may play a role in OTS of endurance athletes. The purpose of this study was to investigate relationships in TH and symptoms of OTS in track and field endurance runners (ER). Methods: Sixteen female track and field middle distance (MD; n = 9; age: 20.2 ± 1.5 years; ht: 167.86 ± 5.04 cm; body-mass: 57.97 ± 5.05 kg; VO2MAX: 53.62 ± 6.04 ml/kg/min) and long distance (LD; n = 7; age: 20.5 ± 1.5 years; ht: 162.48 ± 6.11 cm; body-mass: 56.15 ± 5.99 kg; VO2MAX: 61.94 ± 3.29 ml/kg/min) ER participated in this descriptive study (15-weeks). Thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4), were collected at pre-(PRE) and post-season (POST). A fatigue scale was administered weekly, and percent change (PΔ) in race time (season best vs. championship performance) was calculated. Wilcoxon-sign ranked tests and Spearman’s rho correlations were used to determine changes and relationships between TH and performance. Results: TSH, T3 and T4 did not change from PRE to POST. The percent change (PΔ) in T3 from PRE to POST was correlated with running performance at the end of the season (ρ = − 0.70, p = 0.036). Fatigue at week 12 correlated with running performance at the end of the season (ρ = − 0.74, p = 0.004). Conclusion: TH may be valuable in assessing the overall training state of ER. TH concentrations change too slowly to be a frequent marker of monitoring OTS, but are related to markers of decreased performance. Monitoring dietary intake, and fatigue may be predictive markers to assess OTS and training status of female ER