This study aimed to determine the influence of acute resistance exercise (RE) and biological sex on subjective gastrointestinal (GI) symptoms, GI epithelial damage, and GI permeability in resistance-trained males and females.Thirty resistance-trained men ( n = 15) and women ( n = 15) completed an RE bout and a nonexercise control (CON) session in a randomized counterbalanced design. The RE protocol used a load of 70% one-repetition maximum for 4 sets of 10 repetitions with a 90-s rest period length between sets and a 120-s rest period between exercises (squat, seated shoulder press, deadlift, bent-over row, and leg press). Blood samples were collected before exercise (PRE), immediately postexercise (IP), and 15-, 30-, and 60-min postexercise. Participants completed GI symptom questionnaires to assess subjective GI symptoms PRE, IP, and 60-min postexercise. Blood samples were assayed to quantify small intestine damage (I-FABP) and GI permeability (lactulose-rhamnose [L/R] ratio). Data were analyzed via separate repeated-measures ANOVA, and area under the curve (AUC) analyses were completed via one-way ANOVA.Participants reported greater GI symptoms in RE at IP compared with CON ( P < 0.001) with 70% of participants reporting at least one GI symptom with no differences between sexes. Nausea was the most reported GI symptom (63.3%), followed by vomiting (33.3%). I-FABP and L/R ratio did not exhibit differential responses between conditions. However, L/R ratio AUC was greater in males after RE than male CON ( P = 0.002) and both conditions for females ( P < 0.05). Furthermore, I-FABP AUC in the male RE condition was greater than both female conditions ( P < 0.05).Resistance-trained individuals experience GI distress after RE, with males incurring the greatest increases in markers of GI damage and permeability.
The purpose of this study was to examine the effect of the L-Alanyl-L-Glutamine dipeptide (AG) on cognitive function and reaction time (RT) following endurance exercise. Twelve male endurance athletes (23.5 ± 3.7 y; 175.5 ± 5.4 cm; 70.7 ± 7.6 kg) performed four trials, each consisting of running on a treadmill at 70% of VO2max for 1h, then at 90% of VO2max until exhaustion. One trial consisted of no hydration (DHY), another required ingestion of only a sports electrolyte drink (ED) and two trials required ingestion of a low dose (LD; 300 mg·500 ml(-1)) and high dose (HD) of AG (1 g·500ml(-1)) added to the ED. Cognitive function and reaction tests were administered pre- and post-exercise. Magnitude based inferences were used to analyze ∆ cognitive function and ∆ reaction test data. Results indicated that DHY had a possible negative effect on number of hits in a 60-sec reaction test compared to LD and HD, while ED appeared to have a negative effect compared to HD. Analysis of lower body quickness indicated that LD and HD were likely improved in comparison to DHY. Performance on the serial subtraction test appeared to be possibly better in ED than DHY, while other comparisons between groups regarding cognitive function were unclear. In conclusion, rehydrating with AG during submaximal exercise may maintain or enhance subsequent RT in upper and lower body activities compared to DHY. These same effects were not apparent when participants consumed ED.
Muscle architecture is a determinant for sprinting speed and jumping power, which may be related to anaerobic sports performance. In the present investigation, the relationships between peak (PVJP) and mean (MVJP) vertical jump power, 30m maximal sprinting speed (30M), and muscle architecture were examined in 28 college-aged, recreationally-active men (n = 14; 24.3 ± 2.2y; 89.1 ± 9.3kg; 1.80 ± 0.07 m) and women (n = 14; 21.5 ± 1.7y; 65.2 ± 12.4kg; 1.63 ± 0.08 m). Ultrasound measures of muscle thickness (MT), pennation angle (PNG), cross-sectional area (CSA), and echo intensity (ECHO) were collected from the rectus femoris (RF) and vastus lateralis (VL) of both legs; fascicle length (FL) was estimated from MT and PNG. Men possessed lower ECHO, greater muscle size (MT & CSA), were faster, and were more powerful (PVJP & MVJP) than women. Stepwise regression indicated that muscle size and quality influenced speed and power in men. In women, vastus lateralis asymmetry negatively affected PVJP (MT: r = -0.73; FL: r = -0.60) and MVJP (MT: r = -0.76; FL: r = -0.64), while asymmetrical ECHO (VL) and FL (RF) positively influenced MVJP (r = 0.55) and 30M (r = 0.57), respectively. Thigh muscle architecture appears to influence jumping power and sprinting speed, though the effect may vary by gender in recreationally-active adults. Appropriate assessment of these ultrasound variables in men and women prior to training may provide a more specific exercise prescription. Key pointsThe manner in which thigh muscle architecture affects jumping power and sprinting speed varies by gender.In men, performance is influenced by the magnitude of muscle size and architecture.In women, asymmetrical muscle size and architectural asymmetry significantly influence performance.To develop effective and precise exercise prescription for the improvement of jumping power and/or sprinting speed, muscle architecture assessment prior to the onset of a training program is advised.
BACKGROUND: Physiological adaptation consequent to resistance training is thought to be specific to training intensity and training volume. However, studies comparing high intensity and high training protocols on muscle strength and growth in experienced, resistance trained (RT) men are limited. PURPOSE: Compare high volume versus high intensity training on changes in lean body mass, bone mineral content (BMC), bone area (BA), and bone mineral density (BMD) in the upper body. In addition, changes in upper body strength and power were also examined in RT men. METHODS: Following a 2-wk preparatory phase, 29 RT men completed pre-testing (PRE) measures of skeletal and muscular mass via dual energy X-ray absorptiometry to determine BMC, BA, BMD, and lean arm mass (LAM). Peak (PP) and mean (MP) power were determined by a linear force transducer attached to the barbell during one repetition maximum (1RM) assessment of the bench press (BP), as well as during a single repetition at a resistance corresponding to 40, 60, 80% of the participant’s BP 1RM. Participants were then randomly selected to complete either a high volume, low intensity (HV, n = 14, 4 x 10-12RM, 1min rest) or a high intensity, low volume (HI, n = 15, 4 x 3-5RM, 3min rest) whole body resistance training program. Participants completed post-testing following 8-wks (4 d · wk-1) of training. Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences among the groups. RESULTS: The ANCOVA indicated significant differences for POST BP 1RM (p=0.013, [[Unsupported Character - Symbol Font η]][[Unsupported Character - Symbol Font 2]]=0.214), LAM (p=0.036, [[Unsupported Character - Symbol Font η]][[Unsupported Character - Symbol Font 2]]=0.158), and BMC (p=0.035, [[Unsupported Character - Symbol Font η]][[Unsupported Character - Symbol Font 2]]=0.160). The group means (± standard error) for the adjusted POST variables were HI 121.76 ± 2.25 vs HV 113.11 ± 2.33kg for 1RM BP, HI 10.2 ± 0.11 vs HV 9.84 ± 0.12kg for LAM, and HI 548.56 ± 4.10 vs HV 535.40 ± 4.25g for BMC. No other group differences were observed between the two RT protocols. CONCLUSIONS: The results of the study indicate that during an 8-wk training program in RT men that the HI RT protocol may provide a greater stimulus to bone and muscle tissue adaptation than HV. However, no preferential increase in peak or mean power between the two protocols were observed.
PURPOSE: To examine the monocyte subset response to resistance exercise and supplementation with an aqueous proprietary polyphenol blend (PPB) sourced from Camellia sinensis. METHODS: Untrained men (n=38, 22.1 ± 3.1 yrs; 174.0 ± 7.9 cm; 77.8 ± 14.5 kg) were randomized to: PPB (n=13), placebo (PL; n=15) or control (CON; n=10). PPB and PL supplemented for 28 days prior to an acute bout of resistance exercise, consisting of 10 repetitions at 70% of 1-RM for the squat (6 sets), leg press (4 sets) and leg extension (4 sets). Blood was drawn pre (PR), immediately (IP), 1 (1H), 5 (5H), 24 (24H) and 48 (48H) hours post exercise (PPB/PL), or rest (CON). Biopsies were obtained from the vastus lateralis at PR, 1H, 5H and 48H. Plasma and intramuscular monocyte chemoattractant protein-1 (MCP-1) was assessed by multiplex assay. Relative percent of classical (CLAS; CD14++/CD16-), intermediate (INT; CD14++/CD16+) and nonclassical (NC; CD14+/CD16+) monocytes were assessed via flow cytometry. Repeated measures ANOVA were applied, and non-normally distributed data were LN transformed. RESULTS: A group x time interaction was observed for circulating MCP-1 (p = 0.005), which was greater at 5H in PPB (502.0 ± 154.2 pg[BULLET OPERATOR]ml-1; p = 0.001) and PL (416.8 ± 109.9 pg[BULLET OPERATOR]ml-1; p = 0.012) than CON (307.3 ± 142.6 pg[BULLET OPERATOR]ml-1). A time effect was observed for intramuscular MCP-1 content (p < 0.001), with elevations observed (PR: 9.6 ± 5.0 pg[BULLET OPERATOR]mg-1; p < 0.001) at 1H (374.2 ± 388.8 pg[BULLET OPERATOR]ml-1), 5H (595.7 ± 528.6 pg[BULLET OPERATOR]ml-1) and 48H (217.0 ± 189.1 pg[BULLET OPERATOR]ml-1). Interactions were observed for CLAS, INT and NC (p < 0.001) populations. At IP, CLAS was reduced in PPB (86.2 ± 7.6%; p = 0.008) and PL (85.9 ± 5.1%; p = 0.003) versus CON (93.8 ± 4.3%). At 1H, PPB (96.3 ± 2.0%; p = 0.002) and PL (95.3 ± 4.0%; p = 0.006) was greater than CON (90.8 ± 4.3%). INT were greater at IP in PPB (4.9 ± 2.3%; p = 0.034) and PL (6.0 ± 2.0; p = 0.001) than CON (2.9 ± 1.8%) and reduced at 1H in PPB (1.6 ± 1.0%; p = 0.003) and PL (2.0 ± 1.2%; p = 0.008) versus CON (3.4 ± 1.6%). PPB was greater than CON at 24H (6.7 ± 2.9%; 4.0 ± 0.9%; p = 0.016) and 48H (7.9 ± 3.4%; 4.1 ± 1.6%; p = 0.007). NC was greater at IP in PPB (8.9 ± 6.9%; p = 0.020) and PL (8.1 ± 4.0%; p = 0.028) than CON (3.4 ± 3.2%). CONCLUSIONS: Exercise resulted in increased MCP-1 and the mobilization of specific monocyte subsets. Supplementation with PPB may augment the monocyte response. Funded by Kemin Foods, L.C.
During the competitive soccer season, women's intercollegiate matches are typically played on Friday evenings and Sunday afternoons. The efficacy of a 42-h recovery period is not well understood. This investigation was conducted to determine performance differences between Friday and Sunday matches during a competitive season.Ten NCAA Division I female soccer players (20.5±1.0 y, 166.6±5.1 cm, 61.1±5.8 kg) were monitored with 10-Hz GPS devices across 8 weekends with matches played on Friday evenings and Sunday afternoons. The players were outside backs, midfielders, and forwards. All players had to participate in a minimum of 45 min/match to be included in the study. Average minutes played, total distance covered, total distance of high-intensity running (HIR) (defined as running at a velocity equal to or exceeding 3.61 m/s for longer than 1 s), the number of HIR efforts, and the number of sprints were calculated for each match. Data for Friday vs Sunday matches were averaged and then compared using dependent t tests.No differences were seen in minutes played, distance rate, or number of sprints between Friday and Sunday matches. A significant (P=.017) decrease in rate of HIR between Friday (25.37±7.22 m/min) and Sunday matches (22.90±5.70 m/min) was seen. In addition, there was a trend toward a difference (P=.073) in the number of efforts of HIR between Friday (138.41±36.43) and Sunday (126.92±31.31).NCAA Division I female soccer players cover less distance of HIR in games played less than 48 h after another game. This could be due to various factors such as dehydration, glycogen depletion, or muscle damage.
Abstract Resistance training may differentially affect morphological adaptations along the length of uni-articular and bi-articular muscles. The purpose of this study was to compare changes in muscle morphology along the length of the rectus femoris (RF) and vastus lateralis (VL) in response to resistance training. Following a 2-wk preparatory phase, 15 resistance-trained men (24.0 ± 3.0 y, 90.0 ± 13.8 kg, 174.9 ± 20.7 cm) completed pre-training (PRE) assessments of muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity in the RF and VL at 30, 50, and 70% of each muscle’s length; fascicle length (FL) was estimated from respective measurements of MT and PA within each muscle and region. Participants then began a high intensity, low volume (4 × 3 − 5 repetitions, 3min rest) lower-body resistance training program, and repeated all PRE-assessments after 8 weeks (2 d · wk −1 ) of training (POST). Although three-way (muscle [RF, VL] × region [30, 50, 70%] × time [PRE, POST]) repeated measures analysis of variance did not reveal significant interactions for any assessment of morphology, significant simple (muscle × time) effects were observed for CSA (p = 0.002) and FL (p = 0.016). Specifically, average CSA changes favored the VL (2.96 ± 0.69 cm 2 , pp < 0.001) over the RF (0.59 ± 0.20 cm 2 , p = 0.011), while significant decreases in average FL were noted for the RF (–1.03 ± 0.30 cm, p = 0.004) but not the VL (–0.05 ± 0.36 cm, p = 0.901). No other significant differences were observed. The findings of this study demonstrate the occurrence of non-homogenous adaptations in RF and VL muscle size and architecture following 8 weeks of high-intensity resistance training in resistance-trained men. However, training does not appear to influence region-specific adaptations in either muscle.
Recently, there is growing usage of prebiotics and probiotics as dietary supplements due to their purported health benefits. AG1® (AG1) is a novel foundational nutrition supplement which contains vitamins, minerals, phytonutrients, wholefood concentrates, adaptogens, and functional mushrooms. AG1 could be classified as a synbiotic because it contains traditional and non-traditional prebiotics (e.g., inulin and phytonutrients) as well as lactic-acid-producing probiotics. The purpose of this study was to employ the Simulator of Human Intestinal Microbial Ecosystem (SHIME®) model, which measures various aspects of gastrointestinal fermentation, to investigate the synbiotic effects of AG1. The SHIME experiment quantified gas production, changes in pH, and byproducts of carbohydrate and protein fermentation at baseline, 1, 24, and 48 h following the administration of AG1 or a blank control. The results indicated that AG1 significantly increased (p < 0.05; 41.9% increase) the production of total short-chain fatty acids (SCFAs) including acetate (p = 0.001; 49.0% increase) and propionate (p < 0.001; 70.8% increase). Regarding non-carbohydrate fermentation byproducts, AG1 produced a small but significant increase in ammonium production (p = 0.02; 5.1% increase) but did not promote significant branched-chain SCFA production. These data suggest fermentation occurred in a transplanted human colonic microbiota and these processes were enhanced by the AG1 nutritional supplement. Ultimately, AG1 showed preclinical evidence as a synbiotic given the significant increases in total SCFA production, acetate, propionate, and other metabolic byproducts of fermentation.
Research has demonstrated an increase in free radical production, oxidative stress, and apoptotic signaling following resistance exercise. Thus, identifying dietary strategies to prevent or attenuate exercise-induced cellular stress and apoptotic activity are of interest. PURPOSE: To examine the effects of 28-days of supplementation with an aqueous proprietary polyphenol blend (PPB) sourced from Camellia sinensis on intramuscular apoptotic signaling following an acute lower-body resistance exercise protocol and subsequent recovery. METHODS: Untrained males (n=38, 21.8 ± 2.7 y, 1.7 ± 0.1 m, 77.6 ± 14.6 kg) were randomized to PPB (n = 14), placebo (PL; n = 14) or control (CON; n = 10). Participants completed a lower-body muscle-damaging resistance exercise protocol comprised of 10 repetitions at 70% of 1-RM for the squat (6 sets), leg press (4 sets) and leg extension (4 sets), with 90 seconds of rest between sets. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1HR), 5-hour (5HR), and 48-hours (48HR) post-resistance exercise. Apoptotic signaling pathways were quantified using multiplex signaling assay kits to quantify total proteins (Caspase 3, 8, 9) and markers of phosphorylation status (JNK, FADD, p53, BAD, Bcl-2). Change scores from PRE were calculated for each group (PBB, PL, CON) and analyzed by magnitude based inferences to compare the effects of each condition on intramuscular signaling following resistance exercise. The precision of the magnitude inference was set at 90% confidence limits using the p value corresponding to the t-statistic. RESULTS: Magnitude based inferences indicated a “likely” decrease in total Caspase 3 and “possibly” decreased total Caspase 9 in PPB compared to PL from PRE-5H. JNK phosphorylation was “likely” decreased from PRE-5H in PPB compared to PL. BAD was “very likely” decreased from PRE-5H in PPB when compared to PL and Bcl-2 was “likely” decreased from PRE-1H and PRE-5H in PPB compared to PL. Phosphorylation of p53 was “likely increased” in PPB compared to PL from PRE-1H and PRE-48H. CONCLUSION: These data indicate that chronic supplementation with PPB may attenuate or delay indices of apoptosis in skeletal muscle following an acute muscle-damaging resistance exercise. Supported by Kemin Foods L.C.
