The biphasic activity of autophagy and heat shock protein response in peripheral blood mononuclear cells following acute resistance exercise in resistance-trained males.

PURPOSE: Autophagy and heat shock protein (HSP) response are proteostatic systems involved in the acute and adaptive responses to exercise. These systems may upregulate sequentially following cellular stress including acute exercise, however, currently few data exist in humans. This study investigated the autophagic and HSP responses to acute intense lower body resistance exercise in peripheral blood mononuclear cells (PBMCs) with and without branched-chain amino acids (BCAA) supplementation. METHODS: Twenty resistance-trained males (22.3 ± 1.5 yr; 175.4 ± .7 cm; 86.4 ± 15.6 kg) performed a bout of intense lower body resistance exercise and markers of autophagy and HSP70 were measured immediately post- (IPE) and 2, 4, 24, 48, and 72 h post-exercise. Prior to resistance exercise, 10 subjects were randomly assigned to BCAA supplementation of 0.22 g/kg/d for 5 days pre-exercise and up to 72 h following exercise while the other 10 subjects consumed a placebo (PLCB). RESULTS: There were no difference in autophagy markers or HSP70 expression between BCAA and PLCB groups. LC3II protein expression was significantly lower 2 and 4 h post-exercise compared to pre-exercise. LC3II: I ratio was not different at any time point compared to pre-exercise. Protein expression of p62 was lower IPE, 2, and 4 h post-exercise and elevated 24 h post-exercise. HSP70 expression was elevated 48 and 72 h post-exercise. CONCLUSIONS: Autophagy and HSP70 are upregulated in PBMCs following intense resistance exercise with autophagy increasing initially post-exercise and HSP response in the latter period. Moreover, BCAA supplementation did not affect this response.

Effects of an external pneumatic compression device vs static compression garment on peripheral circulation and markers of sports performance and recovery.

PURPOSE: To identify the effects of a single 30 min partial lower leg external pneumatic compression (EPC) treatment compared to a static compression (SC) garment or a no treatment control (CTL) on markers of recovery and performance following a muscle damaging protocol. METHODS: Thirty healthy, active males (23 ± 3 years; 180.2 ± 9.0 cm; 81.6 ± 11.3 kg) performed 100 drop jumps from a 0.6 m box followed by a randomized, single 30 min treatment of either a partial lower leg EPC device worn below the knee and above the ankle (110 mmHg), SC garment (20-30 mmHg) covering the foot and calf just below the knee, or no treatment CTL, and then returned 24 and 48 h later. Participants were assessed for measures of muscle soreness, fatigue, hemodynamics, blood lactate, muscle thickness, circumferences, and performance assessments. RESULTS: The drop jump protocol significantly increased muscle soreness (p < 0.001), fatigue (p < 0.001), blood flow (p < 0.001), hemoglobin (p < 0.001), and muscle oxygen saturation (SMO2; p < 0.001). Countermovement jump and squat jump testing completed after treatment with either EPC, SC, or CTL revealed no differences for jump height between any condition. However, EPC treatment maintained consistent braking force and propulsive power measures across all timepoints for countermovement jump testing. EPC and SC treatment also led to better maintenance of squat jump performance for average relative propulsive force and power variables at 24 and 48 h compared to CTL. CONCLUSIONS: A single 30 min partial leg EPC treatment may lead to more consistent jump performance following a damaging bout of exercise.

Changes in Energy Expenditure, Dietary Intake, and Energy Availability Across an Entire Collegiate Women's Basketball Season.

ABSTRACT: Zanders, BR, Currier, BS, Harty, PS, Zabriskie, HA, Smith, CR, Stecker, RA, Richmond, SR, Jagim, AR, and Kerksick, CM. Changes in energy expenditure, dietary intake, and energy availability across an entire collegiate women's basketball season. J Strength Cond Res 35(3): 804-810, 2021-The purpose of this study was to identify changes in energy expenditure and dietary intake across an entire women's basketball season. On 5 different occasions across the competitive season, female collegiate basketball players (19.8 ± 1.3 years, 173.9 ± 13.6 cm, 74.6 ± 9.1 kg, 27.1 ± 3.2% fat, 53.9 ± 6.4 ml·kg-1·min-1, n = 13) were outfitted with heart rate and activity monitors over 4 consecutive days and completed 4-day food and fluid records to assess changes in energy expenditure and dietary status. Dual-energy x-ray absorptiometry was used to assess baseline body composition and resting energy expenditure (REE) was measured before and after the season. Data were analyzed using 1-factor repeated-measures analysis of variance. Total daily energy expenditure (TDEE, p = 0.059) and physical activity levels (TDEE/REE, p = 0.060) both tended to decrease throughout the season. Energy balance was negative at all time points throughout the season. Absolute and normalized daily protein intake at the end of the season was significantly (p < 0.05) lower than at the beginning of the season. Carbohydrate (3.7 ± 0.4 g·kg-1·d-1) and protein (1.17 ± 0.16 g·kg-1·d-1) intakes were lower than commonly recommended values based on previously published guidelines. These findings suggest that greater education and interventions for collegiate athletes and coaches regarding dietary intake and energy expenditure are warranted.

Position-Specific Body Composition Values in Female Collegiate Rugby Union Athletes.

ABSTRACT: Harty, PS, Zabriskie, HA, Stecker, RA, Currier, BS, Moon, JM, Richmond, SR, Jagim, AR, and Kerksick, CM. Position-specific body composition values in female collegiate rugby union athletes. J Strength Cond Res 35(11): 3158-3163, 2021-Rugby union is a full-contact, intermittent team sport. Anthropometric characteristics of rugby union athletes have been shown to influence suitability for a given position and affect performance. However, little anthropometric data exist in female rugby union athletes. Thus, the purpose of this study was to report position-specific anthropometric, body composition, and bone density values in female collegiate rugby union athletes and to identify between-position differences in these variables. This investigation was a cross-sectional study involving 101 female collegiate rugby union athletes, categorized as forwards and backs as well as by position (props, hookers, locks, flankers, number 8 forwards, halfback, fly-half, centers, wings, and fullbacks). Anthropometric characteristics of all athletes were measured, and body composition was assessed via dual-energy x-ray absorptiometry. Outcome variables included age, height, body mass, BMI, body fat percentage, fat mass (FM), FM index, fat-free mass (FFM), FFM index, lean soft tissue, bone mineral content, bone mineral area, and bone mineral density. Anthropometric and body composition differences between forwards and backs were identified via independent t-tests and Mann-Whitney U tests, depending on normality of the variable. Between-position differences were assessed using one-way analysis of variances (ANOVAs) with Tukey post-hoc comparisons or Welch's ANOVA with Dunnett's T3 post-hoc test. Significant differences (p < 0.014) were identified between forwards and backs for every anthropometric variable, with forwards displaying greater height (167.7 ± 7.2 cm), body mass (81.5 ± 15.1 kg), and body fat percentage (28.2 ± 6.1%) relative to backs (164.5 ± 5.1 cm; 64.5 ± 7.7 kg; 21.9 ± 3.7%). Likewise, significant differences were identified for every anthropometric variable between several positions (p < 0.01). Significant (p < 0.05) interposition differences were identified within the subgroup of forwards, but not within the subgroup of backs. The present investigation is the first to report position-specific anthropometric and body composition data in female collegiate rugby union athletes. The results of this study can be used by rugby union coaches for recruiting and personnel decisions, to determine a player's suitability for a given position, and to further inform training and nutritional interventions in this population.

Upper and lower thresholds of fat-free mass index in a large cohort of female collegiate athletes.

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.

Sex Differences in Resting Metabolic Rate Among Athletes.

Jagim, AR, Camic, CL, Askow, A, Luedke, J, Erickson, J, Kerksick, CM, Jones, MT, and Oliver, JM. Sex differences in resting metabolic rate among athletes. J Strength Cond Res 33(11): 3008-3014, 2019-The purpose of this study was to compare differences in resting metabolic rate (RMR) between sexes in Division III National Collegiate Athletic Association (NCAA) collegiate athletes and to identify predictors of RMR. Sixty-eight male (M) (age: 20.1 ± 1.5 years; height: 181.8 ± 5.9 cm; body mass (BM): 93.7 ± 16.3 kg; and body fat%: 16.3 ± 8.6%) and 48 female (F) athletes (age: 19.4 ± 1.3 years; height: 166.5 ± 6.0 cm; BM: 63.4 ± 12.7 kg; and body fat%: 21.5 ± 6.3%) participated in a single day of testing, which included determination of RMR using indirect calorimetry and air displacement plethysmography to measure fat mass and fat-free mass (FFM). An independent-samples t-test was used to compare differences in body composition and RMR between sexes, and regression analysis was used to identify predictors of RMR. Men had a significantly higher absolute RMR (M: 2,481 ± 209 vs. F: 1,553 ± 193 kcals·d; p < 0.001), but when adjusted for BM (M: 25.6 ± 8.3 vs. F: 25.9 ± 2.5 kcals·kg BM per day; p = 0.82) and FFM (M: 31.1 ± 10.6 vs. F: 33.6 ± 3.8 kcals·kg FFM per day; p = 0.12), these differences became nonsignificant. Regression analysis indicated that BM in both men (ß = 0.73) and women (ß = 0.88) was the strongest predictor of RMR. The results of the current study indicate minimal differences in RMR between sexes among athletic populations when adjusted for BM and FFM. In the current group of athletes, BM seems to account for the largest variability in RMR.

Fat-Free Mass Index in a Diverse Sample of Male Collegiate Athletes.

Currier, BS, Harty, PS, Zabriskie, HA, Stecker, RA, Moon, JM, Jagim, AR, and Kerksick, CM. Fat-free mass index in a diverse sample of male collegiate athletes. J Strength Cond Res 33(6): 1474-1479, 2019-Fat-free mass index (FFMI) is a body composition metric that has been used to assess relative muscularity in athletes. Fat-free mass index is calculated by dividing FFM by height squared, although further height corrections through linear regression may be needed in taller individuals. This study reported height-adjusted FFMI (FFMIAdj) data in 209 male collegiate athletes from 10 sports (baseball, cross country, football, golf, ice hockey, weightlifting, rugby, swimming, track and field, and water polo) and the FFMIAdj natural upper limit for sports with sufficient sample size. The body composition of all subjects (mean ± SD; age: 20.7 ± 1.9 years, height: 182.9 ± 6.7 cm, body mass: 90.8 ± 16.8 kg, and percent body fat: 15.6 ± 5.3) was measured using dual-energy x-ray absorptiometry. Linear regression was used to adjust for height, and the FFMIAdj natural upper limit was determined by calculating the 97.5th percentile of all values. One-way analyses of variance with Games-Howell post hoc comparisons were used to determine between-sport differences. A paired-samples t-test revealed a significant difference (p < 0.001) between unadjusted and adjusted mean FFMI values. The overall mean FFMIAdj was 22.8 ± 2.8 kg·m. Significant between-sport differences (p < 0.001) in FFMIAdj were identified. Average FFMIAdj was highest in football athletes (24.28 ± 2.39 kg·m) and lowest in water polo athletes (20.68 ± 3.56 kg·m). The FFMIAdj upper limit was calculated for all athletes (28.32 kg·m), rugby (29.1 kg·m), and baseball (25.5 kg·m). This study reported FFMIAdj values in a diverse cohort of male collegiate athletes, providing data for the first time in several sports. These values can be used to guide nutritional and exercise interventions, predict athletic performance, and provide coaches with standardized information regarding the potential for further FFM accretion in male athletes.

Determining a Resting Metabolic Rate Prediction Equation for Collegiate Female Athletes.

Watson, AD, Zabriskie, HA, Witherbee, KE, Sulavik, A, Gieske, BT, and Kerksick, CM. Determining a resting metabolic rate prediction equation for collegiate female athletes. J Strength Cond Res 33(9): 2426-2432, 2019-A lack of evidence exists regarding the accuracy of common resting metabolic rate (RMR) prediction equations in athletic female populations. The purpose of this research was to measure RMR in a large cohort of NCAA Division II female athletes and use regression techniques to develop new prediction equations. Sixty-six female athletes from 11 different sports completed this protocol, which included skinfold measurements followed by an RMR assessment using indirect calorimetry. The average RMR was 1,466 ± 150 kcal·d. Many between-sport differences in body composition were identified, with gymnastics athletes having the lowest body fat percentage (p < 0.05) and basketball athletes having the greatest absolute fat-free mass (p < 0.05). Resting metabolic rate was moderately correlated (p < 0.05) with height (r = 0.52), total mass (r = 0.59), and fat-free mass (r = 0.54). Two equations were developed, both of which were more accurate for this population than other RMR prediction equations. One of the new equations, which used height and body mass as covariates (equation 1), was slightly more accurate than the equation using body composition parameters (equation 2). The new equations were cross-validated using a randomly selected subset (n = 22) of the original sample. The subset did not show statistically different results from the remainder of the sample (n = 44) between equation 1 (p = 0.083) and equation 2 (p = 0.22). Equation 1, which had more easily measurable parameters, exhibited heightened accuracy, which has important implications for implementation among athletes, coaches, and athletic support staff.

Effect of Carbohydrate, Caffeine, and Carbohydrate + Caffeine Mouth Rinsing on Intermittent Running Performance in Collegiate Male Lacrosse Athletes.

Dolan, P, Witherbee, KE, Peterson, KM, and Kerksick, CM. Effect of carbohydrate, caffeine, and carbohydrate + caffeine mouth rinsing on intermittent running performance in collegiate male lacrosse athletes. J Strength Cond Res 31(9): 2473-2479, 2017-Recently, an interest has developed in the potential to rinse the oral cavity with key nutrients to impact various types of exercise and presumably sporting performance. Although multiple studies examining carbohydrate mouth rinsing have been completed, conflicting evidence surrounding caffeine mouth rinsing persists, and no research has explored its ability to impact high-intensity, intermittent running performance. This study investigated the independent and synergistic ability of carbohydrate and caffeine mouth rinsing to improve intermittent running performance. The Yo-Yo Intermittent Recovery Test-Level 1 (Yo-Yo Level 1) was completed in 10 collegiate (National Collegiate Athletic Association [NCAA] Division II) male lacrosse players after a 10-second mouth rinse with a solution of either carbohydrate (CHO), caffeine (CAF), carbohydrate + caffeine (CHO + CAF), placebo (H2O), or a no rinse control (CON). No significant improvements in Yo-Yo IRT-1 performance were found (p > 0.05). Perceptual indications of effort (i.e., rating of their perceived exertion [RPE]) were significantly lower (p ≤ 0.05) in CHO and CHO + CAF when compared with CON after speed level 11. Interestingly, RPE levels were nonsignificantly lower in all but one level of the Yo-Yo Level 1 for CHO in comparison with other groups. Carbohydrate and caffeine mouth rinsing seems to exert no impact on running performance before maximal intermittent running in a group of male collegiate lacrosse players.

The Effects of Eccentric Contraction Duration on Muscle Strength, Power Production, Vertical Jump, and Soreness.

Mike, JN, Cole, N, Herrera, C, VanDusseldorp, T, Kravitz, L, and Kerksick, CM. The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. J Strength Cond Res 31(3): 773-786, 2017-Previous research has investigated the effects of either eccentric-only training or comparing eccentric and concentric exercise on changes related to strength and power expression, but no research to date has investigated the impact of altering the duration of either the concentric or the eccentric component on these parameters. Therefore, the purpose of this study was to assess the duration of eccentric (i.e., 2-second, 4-second vs. 6-second) muscle contractions and their effect on muscle strength, power production, vertical jump, and soreness using a plate-loaded barbell Smith squat exercise. Thirty college-aged men (23 ± 3.5 years, 178 ± 6.8 cm, 82 ± 12 kg, and 11.6 ± 5.1% fat) with 3.0 ± 1.0 years of resistance training experience and training frequency of 4.3 ± 0.9 days per week were randomized and assigned to 1 of 3 eccentric training groups that incorporated different patterns of contraction. For every repetition, all 3 groups used 2-second concentric contractions and paused for 1 second between the concentric and eccentric phases. The control group (2S) used 2-second eccentric contractions, whereas the 4S group performed 4-second eccentric contractions and the 6S group performed 6-second eccentric contractions. All repetitions were completed using the barbell Smith squat exercise. All participants completed a 4-week training protocol that required them to complete 2 workouts per week using their prescribed contraction routine for 4 sets of 6 repetitions at an intensity of 80-85% one repetition maximum (1RM). For all performance data, significant group × time (G × T) interaction effects were found for average power production across all 3 sets of a squat jump protocol (p = 0.04) while vertical jump did not reach significance but there was a trend toward a difference (G × T, p = 0.07). No other significant (p > 0.05) G × T interaction effects were found for the performance variables. All groups showed significant main effects for time in 1RM (p < 0.001), vertical jump (p = 0.004), peak power (p < 0.001), and average power (p < 0.001). Peak velocity data indicated that the 6S group experienced a significant reduction in peak velocity during the squat jump protocol as a result of the 4-week training program (p = 0.03). Soreness data revealed significant increases across time in all groups at both week 0 and week 4. Paired sample t-tests revealed greater differences in soreness values across time in the 2S group. The results provide further evidence that resistance training with eccentrically dominated movement patterns can be an effective method to acutely increase maximal strength and power expression in trained college age men. Furthermore, longer eccentric contractions may negatively impact explosive movements such as the vertical jump, whereas shorter eccentric contractions may instigate greater amounts of soreness. These are important considerations for the strength and conditioning professional to more fully understand that expressions of strength and power through eccentric training and varying durations of eccentric activity can have a significant impact for populations ranging from athletes desiring peak performance.

Carbohydrate intake and resistance-based exercise: are current recommendations reflective of actual need?

Substantial research has been completed examining the impact of carbohydrate (CHO) intake on endurance exercise, whereas its role in resistance-based exercise performance, adaptation and cell signalling has yet to be fully characterised. This empirical shortcoming has precluded the ability to establish specific CHO recommendations for resistance exercise. This results in recommendations largely stemming from findings based on endurance exercise and/or anecdotal evidence despite the distinct energetic demands and molecular responses mediating adaptation from endurance- and resistance-based exercise. Moreover, the topic of CHO and exercise has become one of polarising nature with divergent views - some substantiated, others lacking evidence. Current literature suggests a moderately high daily CHO intake (3-7 g/kg per d) for resistance training, which is thought to prevent glycogen depletion and facilitate performance and adaptation. However, contemporary investigation, along with an emerging understanding of the molecular underpinnings of resistance exercise adaptation, may suggest that such an intake may not be necessary. In addition to the low likelihood of true glycogen depletion occurring in response to resistance exercise, a diet restrictive in CHO may not be detrimental to acute resistance exercise performance or the cellular signalling activity responsible for adaptation, even when muscle glycogen stores are reduced. Current evidence suggests that signalling of the mammalian target of rapamycin complex 1, the key regulatory kinase for gene translation (protein synthesis), is unaffected by CHO restriction or low muscular glycogen concentrations. Such findings may call into question the current view and subsequent recommendations of CHO intake with regard to resistance-based exercise.

Intramuscular phosphagen status and the relationship to muscle performance across the age spectrum.

PURPOSE: To examine age-related differences in intramuscular concentrations of adenosine triphosphate (ATP), free creatine (FCr), phosphocreatine (PCr) and total creatine (TCr) and if these differences were related to muscle performance. METHODS: Forty-two healthy, non-sedentary, males between 20 and 76 years provided muscle samples to determine [ATP], [FCr], [PCr], and [TCr]. Maximal strength and endurance were assessed and correlated with intramuscular variables. RESULTS: Intramuscular [ATP] decreased by 13.5% (p = 0.013) in the older cohort (18.0 ± 0.6 mmol/kg dry wt) vs. the young cohort (20.8 ± 0.9 mmol/kg dry wt) and was significantly correlated to age (r = -0.38, p = 0.008). No other differences were observed between age groups for intramuscular [PCr], [FCr], [TCr], or [PCr]:[TCr] (p > 0.05). The older cohort consumed significantly less (p < 0.05) dietary protein when compared to the young cohort. Bivariate correlations were found for intramuscular [ATP] and lower body 1RM (r = 0.24, p = 0.066), leg press volume and free creatine (r = 0.325, p = 0.036) and leg press repetitions and free creatine (r = 0.373, p = 0.015). Partial correlations controlling for age eliminated the relationship between [ATP] and 1RM while intramuscular free creatine and leg press repetitions remained significant (p < 0.05) and leg press volume approached significance (p = 0.095). CONCLUSION: These results expand upon previous observations indicative of age-related reductions in intramuscular [ATP] and dietary protein intake. The lack of change in other intramuscular PCr system markers are suggestive of dysfunctions at the mitochondrial level while the impact of neuromuscular changes, lean mass cross-sectional area and differences in physical activity are also important.

Impact of creatine on muscle performance and phosphagen stores after immobilization.

PURPOSE: This study investigated the effect of creatine (CR) supplementation during cast-immobilization to preserve skeletal muscle total work, power and intramuscular phosphocreatine (PCr) kinetics during dynamic exercise. METHODS: Twenty-five active individuals (24 ± 4 years,) performed wrist flexion exercise within a 1.9 Tesla superconducting magnet before and after 1 week of cast-immobilization. An incremental protocol to fatigue and two constant load (CL1 and CL2) exercise bouts were performed. While casted, participants consumed either 20 g day(-1) of CR or a placebo (PLA). (31)P magnetic resonance spectroscopy was used to quantify in vivo intramuscular PCr levels. RESULTS: No significant group × time interaction effects were found for work or power throughout all exercise bouts. Total work was significantly reduced over time in both groups (p = 0.049) during the incremental exercise bout. Work production in CL1 tended (p = 0.073) to attenuate in the CR group, compared to PLA. No changes were observed in CL2. Baseline PCr significantly decreased with casting in PLA (PRE: 26.6 ± 6.3 vs. POST: 22.5 ± 5.6 mM kg(-1) wet muscle, p = 0.003). No change (p = 0.31) was observed in the CR group. Changes in work production were significantly correlated with changes in resting PCr in CR (r = -0.63, p = 0.021) but not PLA (r = -0.36, p = 0.26) group. CONCLUSIONS: Results suggest decreases in short-term endurance may be due to alternations of PCr status and/or metabolism. More research is needed to fully determine the efficacy of CR supplementation during short-term immobilization.

How can bioinformatics and toxicogenomics assist the next generation of research on physical exercise and athletic performance.

The past 2-3 decades have seen an explosion in analytical areas related to "omic" technologies. These advancements have reached a point where their application can be and are being used as a part of exercise physiology and sport performance research. Such advancements have drastically enabled researchers to analyze extremely large groups of data that can provide amounts of information never before made available. Although these "omic" technologies offer exciting possibilities, the analytical costs and time required to complete the statistical approaches are substantial. The areas of exercise physiology and sport performance continue to witness an exponential growth of published studies using any combination of these techniques. Because more investigators within these traditionally applied science disciplines use these approaches, the need for efficient, thoughtful, and accurate extraction of information from electronic databases is paramount. As before, these disciplines can learn much from other disciplines who have already developed software and technologies to rapidly enhance the quality of results received when searching for key information. In addition, further development and interest in areas such as toxicogenomics could aid in the development and identification of more accurate testing programs for illicit drugs, performance enhancing drugs abused in sport, and better therapeutic outcomes from prescribed drug use. This review is intended to offer a discussion related to how bioinformatics approaches may assist the new generation of "omic" research in areas related to exercise physiology and toxicogenomics. Consequently, more focus will be placed on popular tools that are already available for analyzing such complex data and highlighting additional strategies and considerations that can further aid in developing new tools and data management approaches to assist future research in this field. It is our contention that introducing more scientists to how this type of work can complement existing experimental approaches within exercise physiology and sport performance will foster additional discussion and stimulate new research in these areas.

Factors that contribute to and account for strength and work capacity in a large cohort of recreationally trained adult healthy men with high- and low-strength levels.

The factors that best account for differences in strength across all types of exercise, body types, and training histories are not well understood. The purpose of this study was to assess the effects of strength level and body composition on upper- and lower-body work capacity in adult men. From a cohort of 295 adult men (25.6 ± 7.5 years, 178 ± 8 cm, 85.2 ± 15 kg), low-strength (LS, n = 72) and high-strength (HS, n = 66) samples were selected based on 1 repetition maximum (1RM) bench press (BP) and leg strength (LP) values. Work capacity for each exercise was determined from the product of repetition weight (80% 1RM) and maximum repetitions-to-fatigue (RTF). Body composition was measured using dual-energy x-ray absorptiometry. The HS group was significantly greater than the LS group in total body mass and fat-free mass but not in age, height, fat mass, or %fat. Low-strength and HS groups were not significantly different (p > 0.05) in RTF for either BP (8.7 ± 3.1 vs. 8.3 ± 1.9 reps, respectively) or LP (15.6 ± 7.6 vs. 17.0 ± 6.3 reps, respectively), making the ratio of RTF for BP vs. LP nonsignificant (LS = 2.0 ± 1.0; HS = 2.2 ± 0.9). The HS group produced significantly greater (p < 0.001) absolute and relative work capacities for both BP and LP compared with the LS group. Repetitions-to-fatigue had a greater influence on BP (r2 = 0.74) and LP (r2 = 0.85) work capacities in the LS group than did RepWt (r2 = 0.07 and 0.28, respectively). In the HS group, RTF (r2 = 0.79) had a greater influence than RepWt (r2 = 0.10) on BP work capacity, whereas the 2 components were more similar for LP work capacity (r2 = 0.64 and 0.47, respectively). When evaluated at the same %1RM, muscular endurance is similar across divergent strength levels meaning that work capacity (load × reps) will be greater for HS individuals. Controlling for the influence of body composition variables (e.g., fat or fat-free mass) does not eliminate the difference in work capacity between strength groups suggesting that other factors are accounting for strength expression. Prescribing repetitions against a fixed relative load is largely dependent on exercise type and must be considered by strength and conditioning professionals.

It's Dead! Can Postbiotics Really Help Performance and Recovery? A Systematic Review.

In recent years, postbiotics have increased in popularity, but the potential relevancy of postbiotics for augmenting exercise performance, recovery, and health is underexplored. A systematic literature search of Google Scholar and PubMed databases was performed with the main objective being to identify and summarize the current body of scientific literature on postbiotic supplementation and outcomes related to exercise performance and recovery. Inclusion criteria for this systematic review consisted of peer-reviewed, randomized, double-blind, and placebo-controlled trials, with a population including healthy men or women >18 years of age. Studies required the incorporation of a postbiotic supplementation regimen and an outcome linked to exercise. Search terms included paraprobiotics, Tyndallized probiotics, ghost biotics, heat-killed probiotics, inactivated probiotics, nonviable probiotics, exercise, exercise performance, and recovery. Only investigations written in English were considered. Nine peer-reviewed manuscripts and two published abstracts from conference proceedings were included and reviewed. Supplementation periods ranged from 13 days to 12 weeks. A total of 477 subjects participated in the studies (n = 16-105/study) with reported results spanning a variety of exercise outcomes including exercise performance, recovery of lost strength, body composition, perceptual fatigue and soreness, daily logs of physical conditions, changes in mood states, and biomarkers associated with muscle damage, inflammation, immune modulation, and oxidative stress. Early evidence has provided some indication that postbiotic supplementation may help to support mood, reduce fatigue, and increase the readiness of athletes across several weeks of exercise training. However, more research is needed to further understand how postbiotics may augment health, resiliency, performance, and recovery. Future investigations should include longer supplementation periods spanning a wider variety of competitive athletes and exercising populations.

Differences in perceived energy and macronutrient requirements across divisions in NCAA athletes.

BACKGROUND: Sports nutrition is an impactful component to sports performance. The purpose of the current study was to investigate the sports nutrition knowledge of National Collegiate Athletic Association collegiate athletes and assess self-reported perceived requirements for energy and macronutrient intake. A secondary aim was to evaluate the awareness of physical and emotional perceptions associated with mindful eating. METHODS: Participants included NCAA Division I (DI, n = 45), II (DII, n = 31), and III (DIII, n = 47) athletes. Athletes completed a validated questionnaire designed to assess sports nutrition knowledge and were asked questions about their perceived dietary energy and macronutrient requirements. Daily energy intake values were calculated using a recommended relative energy intake value of 40, 50, and 60 kcal/kg/day for low, moderate, and high activity levels, respectively. Carbohydrate recommendations were calculated using 4, 6, and 8 g/kg/day, protein recommendations were calculated using relative intakes of 1.4, 1.6, and 1.8 g/kg/day, and fat recommendations were calculated from a relative percentage of total predicted daily energy requirements, equating to 15, 25, and 30% of daily energy. Additionally, athletes completed a questionnaire to assess mindfulness regarding eating habits. RESULTS: Overall, athletes answered 45.5 ± 13.5% of questions correctly on the nutrition questionnaire with significant differences observed between male (48.6 ± 13.6%) and female athletes (43.6 ± 13.2%; p = 0.044), as well as significant differences observed between DI athlete scores (38.8 ± 14.1%) and DII athletes (47.7 ± 11.4%; p = 0.002), and DI athletes and DIII athletes (51.71 ± 11.83%; p = <0.001). All athletes significantly (p < 0.001) underestimated daily energy intake requirements (female, 2,112 ± 575 kcal/day; male, 3,283 ± 538 kcal/day). The mindfulness eating habits total score was significantly higher in male athletes (65.1 ± 6.5) compared to female athletes (60.9 ± 9.5; p = 0.009). CONCLUSIONS: Division I, II, and III collegiate athletes have poor sports nutrition knowledge, with Division I athletes having exhibited lower scores compared to Division II and III athletes on the sports nutrition knowledge questionnaire. Athletes from all levels of collegiate sports underestimated their energy and macronutrient requirements. Differences in mindful eating habits among female and male athletes were also evident.

Milk or Kefir, in Comparison to Water, Do Not Enhance Running Time-Trial Performance in Endurance Master Athletes.

This study compared flavored kefir (KFR) and flavored milk (MLK) as a recovery drink in endurance master athletes. Using a randomized, placebo-controlled, non-blinded crossover design, 11 males and females completed three testing visits whilst acutely ingesting either KFR, MLK, or water as a placebo (PLA). KFR supplementation occurred for 14 days before the KFR-testing day, followed by a 3-week washout period. Testing visits consisted of an exhausting-exercise (EE) bout, a 4-h rest period where additional carbohydrate feeding was provided, and a treadmill 5 km time trial (TT). The Gastrointestinal Symptom Rating Scale (GSRS) survey was assessed at four timepoints. Blood was collected at baseline and after the TT and was analyzed for I-FABP levels. No significant difference (PLA: 33:39.1 ± 6:29.0 min, KFR: 33:41.1 ± 5:44.4 min, and MLK: 33:36.2 ± 6:40.5 min, p = 0.99) was found between the groups in TT performance. The KFR GSRS total score was significantly lower than the PLA after EE (p = 0.005). No differences in I-FABP were observed between conditions. In conclusion, acute KFR supplementation did not impact TT performance or I-FABP levels but may have reduced subjective GI symptoms surrounding exercise when compared to MLK or PLA.