A proposed test to determine physical working capacity at pain intensity threshold (PWCPIT).

PURPOSE: This study aimed to establish a new threshold parameter called the physical working capacity at pain intensity threshold (PWCPIT) using a pain intensity scale and mathematical methods similar to those used to develop the physical working capacity at oxygen consumption threshold (PWCVO2) and physical working capacity at heart rate threshold (PWCHRT). The study had two objectives: (i) to examine the relationship between PWCPIT and traditional PWC measures and (ii) to explore the physiological mechanisms underlying the relationship between pain perception and capacity thresholds. METHODS: Fourteen male volunteers (age 21 ± 2 years, height 176 ± 6 cm, weight 76 ± 9 kg, VO2peak 37.8 ± 7.8 ml/kg/min-1) underwent an incremental exhaustion test and four 8-min randomly ordered work bouts on different days at 70-100% peak power output (119-320 W) to establish their PWCPIT, PWCHRT and PWCVO2. One-way repeated-measures ANOVA with Bonferroni post hoc tests and a zero-order correlation matrix were used to analyze these thresholds. RESULTS: PWCPIT significantly correlated with PWCHRT (r = 0.88, P < 0.001), PWCVO2 (r = 0.84, P < 0.001), and gas exchange threshold (GET) (r = 0.7, P = 0.006). CONCLUSION: The model for estimating PWCHRT and PWCVO2 can be applied to determine the PWCPIT. By examining how PWCPIT aligns with, differs from, or complements existing PWC threshold measures, researchers may provide a more comprehensive understanding of the factors that govern endurance performance.

SIRT1 induction in the skeletal muscle of male mice partially preserves limb muscle mass but not contractile force in response to androgen deprivation.

In males, the factors that decrease limb muscle mass and strength in response to androgen deprivation are largely unknown. Sirtuin1 (SIRT1) protein levels are lower in the limb muscle of male mice subjected to androgen deprivation. The present study aimed to assess whether SIRT1 induction preserved limb muscle mass and force production in response to androgen deprivation. Physically mature male mice containing an inducible muscle-specific SIRT1 transgene were subjected to a sham or castration surgery and compared to sham and castrated male mice where the SIRT1 transgene was not induced. SIRT1 induction partially preserved whole-body lean mass, tibialis anterior (TA) mass and triceps surae muscle mass in response to castration. Further analysis of the TA muscle showed that muscle-specific SIRT1 induction partially preserved limb muscle soluble protein content and fibre cross-sectional area. Unilateral AAV9-mediated SIRT1 induction in the TA muscle showed that SIRT1 partially preserved mass by acting directly in the muscle. Despite those positive outcomes to limb muscle morphology, muscle-specific SIRT1 induction did not preserve the force generating capacity of the TA or triceps surae muscles. Interestingly, SIRT1 induction in females did not alter limb muscle mass or limb muscle strength even though females have naturally low androgen levels. SIRT1 also did not alter the androgen-mediated increase in limb muscle mass or strength in females. In all, these data suggest that decreases in SIRT1 protein in the limb muscle of males may partially contribute to the loss of limb muscle mass in response to androgen deprivation. KEY POINTS: SIRT1 induction in skeletal muscle of male mice subjected to androgen deprivation partially preserved limb muscle mass and fibre cross-sectional area. SIRT1 induction in skeletal muscle of male mice subjected to androgen deprivation did not prevent preserve limb muscle force generating capacity. SIRT1 induction in skeletal muscle of females did not alter baseline limb muscle mass, nor did it affect the androgen-mediated increase in limb muscle mass.

Carbohydrate-Protein drink is effective for restoring endurance capacity in masters class athletes after a two-Hour recovery.

BACKGROUND: Carbohydrate (CHO) and carbohydrate-protein co-ingestion (CHO-P) have been shown to be equally effective for enhancing glycogen resynthesis and subsequent same-day performance when CHO intake is suboptimal (≤0.8 g/kg). Few studies have specifically examined the effect of isocaloric CHO vs CHO-P consumption on subsequent high-intensity aerobic performance with limited time to recover (≤2 hours) in masters class endurance athletes. METHODS: This was a randomized, double-blind between-subject design. Twenty-two male masters class endurance athletes (age 49.1 ± 6.9 years; height 175.8 ± 4.8 cm; body mass 80.7 ± 8.6 kg; body fat (%) 19.1 ± 5.8; VO2peak 48.6 ± 6.7 ml·kg·min-1) were assigned to consume one of three beverages during a 2-hour recovery period: Placebo (PLA; electrolytes and water), CHO (1.2 g/kg bm), or CHO-P (0.8 g/kg bm CHO + 0.4 g/kg bm PRO). All beverages were standardized to one liter (~32 oz.) of total fluid volume regardless of the treatment group. During Visit #1, participants completed graded exercise testing on a cycle ergometer to determine VO2peak and peak power output (PPO, watts). Visit #2 consisted of familiarization with the high-intensity protocol including 5 × 4 min intervals at 70-80% of PPO with 2 min of active recovery at 50 W, followed by a time to exhaustion (TTE) test at 90% PPO. During Visit#3, the same high-intensity interval protocol with TTE was conducted pre-and post-beverage consumption. RESULTS: A one-way ANCOVA indicated a significant difference among the group means for the posttest TTE (F2,18 = 6.702, p = .007, ƞ2 = .427) values after adjusting for the pretest differences. TTE performance in the second exercise bout improved for the CHO (295.48 ± 24.90) and CHO-P (255.08 ± 25.07 sec) groups. The water and electrolyte solution was not effective in restoring TTE performance in the PLA group (171.13 ± 23.71 sec). CONCLUSIONS: Both CHO and CHO-P effectively promoted an increase in TTE performance with limited time to recover in this sample of masters class endurance athletes. Water and electrolytes alone were not effective for restoring endurance capacity during the second bout of exhaustive exercise.

Development and test-retest reliability of the Combat Sports Post-Career Health Questionnaire (CSPCHQ).

The long-term impact of weight cycling on health status, eating habits, physical activity and the lifestyle of former combat sports athletes is still insufficiently explored. Therefore, a novel questionnaire in English, Portuguese, Spanish and Croatian language was constructed. To determine the reliability and the content/face validity, a total of 110 participants filled the questionnaire on two occasions. With the majority of intra-class correlation coefficient values above 0·75, the questionnaire items were shown to be very stable. Additionally, according to κ values, the questionnaire has fair test-retest reliability, with only one coefficient being labelled as poor (Q40 in ESP). All questionnaire sub-scales showed moderate to very good internal consistency when the overall sample was observed (α ranging from 0·605 to 0·802). Poor α values were found only in Godin-Shephard Leisure-Time Physical Activity Questionnaire for CRO and ESP samples. Wilcoxon's signed rank test showed significant differences only in the Mindful Eating Questionnaire sub-scale scores (overall: P = 0·002, effect size = -0·208 [moderate]; CRO: P = 0·005, effect size = 0·303 [moderate]). It can be concluded that the newly developed questionnaire had strong test-retest reliability. Further validity research in a larger sample of former combat sports athletes should be considered.

Effects of Interrupted Daily Routine Due to COVID-19 on Circadian Chronotype and Leisure Time Physical Activity.

Circadian chronotype is dependent on many factors including age, physical activity participation, eating and sleeping patterns, and typical schedule. Recently, the COVID-19 pandemic resulted in schedule changes for most individuals. Therefore, the purpose of this study is to examine whether sport participation influences circadian chronotype and physical activity and whether COVID-19 restrictions have impacted chronotype scores. Briefly, 128 physically active males (n = 62) and females (n = 66) between 18 and 55 years old (24.7 ± 7.1) completed a survey consisting of demographics information, the Morningness−Eveningness Questionnaire (MEQ), and the Godin Leisure Time Physical Activity Scale (LTPA). Participants were asked to answer relevant questions about their habits/preferences before and after COVID-19-related restrictions were implemented. MEQ scores categorized individuals into morning (MT), intermediate (IT), and evening (ET) chronotypes. Three-way (pre-COVID-19 chronotype x sport participation x time) repeated measures ANOVA was conducted to evaluate differences in MEQ and LTPA. A significant main effect of time was found for MEQ (p = 0.018) and LTPA (p = 0.002), indicating changes following COVID-19. A significant time x chronotype interaction was shown for MEQ (p < 0.001) with MT (p < 0.001), IT (p = 0.044), and ET (p = 0.044) individuals indicating chronotype-specific changes following COVID-19. LTPA was decreased and MEQ scores changed following COVID-19, with shifts toward IT scores.

Use of Tensiomyography in Evaluating Sex-Based Differences in Resistance-Trained Individuals After Plyometric and Isometric Midthigh Pull Postactivation Potentiation Protocols.

ABSTRACT: Herring, CH, Goldstein, ER, and Fukuda, DH. Use of tensiomyography in evaluating sex-based differences in resistance-trained individuals after plyometric and isometric midthigh pull postactivation potentiation protocols. J Strength Cond Res 35(6): 1527-1534, 2021-The purposes of this study were to determine if there are sex-based differences in muscular contractile properties as measured by tensiomyography (TMG) and to determine if plyometrics or the isometric midthigh pull are effective methods of eliciting postactivation potentiation (PAP). Thirty strong, resistance-trained men (n = 15) and women (n = 15) underwent 3 testing days consisting of a PAP or control protocol, and pre-TMG and post-TMG and performance testing. Contractile properties from TMG were assessed in the gastrocnemius medial head (GMH), gluteus maximus (GM), rectus femoris (RF), and biceps femoris (BF). Performance testing included countermovement jumps (CMJs) and 30-m sprints. A time × sex interaction was found for GM delay time with women primarily influencing changes (mean difference = 2.74 ms) rather than men (mean difference = 1.32 ms). Main effects for time revealed an increase in GMH velocity of contraction (+0.004 mm·ms-1) and reductions in GM contraction time (-2.85 ms), GM delay time (-2.03 ms), RF delay time (-0.65 ms), CMJs (-2.74 cm), and 30-m time (0.05 seconds). Main effects for sex revealed greater values in women for GM contraction time (+15.50 ms), GM delay time (+6.65 ms), RF delay time (+2.26 ms), BF contraction time (+8.44 ms), BF delay time (+4.07 ms), BF maximal displacement (+2.27 mm), and 30-m time (+0.67 seconds), and lower values in women for GM velocity of contraction (-0.039 mm·ms-1) and CMJs (-13.46 cm).These findings may help practitioners optimize performance through enhanced assessments for injury risk, targeting specific muscles for training, and by selecting proper CAs and rest periods when using PAP.

Dynamic post-activation potentiation protocol improves rowing performance in experienced female rowers.

Post-activation potentiation likely acutely improves power-based performance; however, few studies have demonstrated improved endurance performance. Forty collegiate female rowers performed isometric potentiating (ISO), dynamic potentiating (DYN) and control (CON) warm-up protocols on a rowing ergometer, followed by a three-minute all-out test to evaluate their total distance, peak power, mean power, critical power, anaerobic working capacity (W') and stroke rate. Fifteen-second splits were also analysed. ISO consisted of 5 × 5-second static muscle actions with the ergometer handle rendered immovable with a nylon strap, while DYN consisted of 2 × 10-second all-out rowing bouts, separated by a 2-minute rest interval. The participants were divided into high and low experience groups by median experience level (3.75 years) for statistical analysis. Significant differences (DYN > CON; p < 0.05) were found for distance (+5.6 m), mean power (+5.9 W) and W' (+1561.6 J) for more experienced rowers (n = 19) and no differences for less experienced rowers (n = 18). Mean power in DYN was significantly greater than CON and ISO in the 15-30, 30-45, 45-60 and 60-75 second intervals independent of experience level. These results suggest that DYN may benefit experienced female rowers and that these strategies might benefit a greater power output over shorter distances regardless of experience.

Alterations in energy system contribution following upper body sprint interval training.

PURPOSE: The primary purpose of this study was to examine the influence of different work-to-rest ratios on relative energy system utilization during short-term upper-body sprint interval training (SIT) protocols. METHODS: Forty-two recreationally trained men were randomized into one of three training groups [10 s work bouts with 2 min of rest (10:2, n = 11) or 4 min of rest (10:4, n = 11), or 30 s work bouts with 4 min of rest (30:4, n = 10)] or a control group (CON, n = 10). Participants underwent six training sessions over 2 weeks with 4-6 'all-out' sprints. Participants completed an upper body Wingate test (30 s 'all-out' using 0.05 kg kg-1 of the participant's body mass) pre- and post-intervention from which oxygen consumption and blood lactate were used to estimate oxidative, glycolytic, and adenosine triphosphate-phosphocreatine (ATP-PCr) energy system provisions. An analysis of covariance was performed on all testing measurements collected at post with the associated pre-values used as covariates. RESULTS: Relative energy contribution (p = 0.026) and energy expenditure (p = 0.019) of the ATP-PCr energy system were greater in 10:4 (49.9%; 62.1 kJ) compared to CON (43.1%; 47.2 kJ) post training. No significant differences were found between groups in glycolytic or oxidative energy contribution over a 30 s upper body Wingate test. CONCLUSION: SIT protocols with smaller work-to-rest ratios may enhance ATP-PCr utilization in a 30 s upper body Wingate over a 2-week intervention.

Anthropometric characteristics and physical performance of taekwondo athletes / Características antropométricas e desempenho físico de lutadores de taekwondo

Abstract The purpose of this investigation was to measure anthropometric and physical performance variables of TKD athletes from the city of Pelotas - RS. Forty-five athletes aged 16.4 ± 5.2 years and time of practice of 3.25 ± 3.6 years were evaluated. Athletes performed anthropometric evaluation and physical, general and specific performance tests. In the sum of seven skin folds, men presented lower values ??(106.1 ± 49.5 mm versus 143.4 ± 43.2 mm, p <0.002). Male seniors presented better performance in the vertical jump compared to beginners (42.3 ± 8.5cm versus 24.8 ± 10.1cm, p <0.03) and to women (22.1 ± 4.3cm, p <0.03). Graduated individuals perform higher number of arm pushups than beginners and women and more repetitions in the abdominal test. Male junior and senior athletes had higher isometric handgrip strength than females (48.3 ± 3.9 kgf and 38.1 ± 12.6 kgf versus 29 ± 5.6 kgf, p <0.001). Men covered longer distance in the yo-yo test than women (606.6 ± 233.8m versus 200 ± 113.1m, p <0.001). In the Wingate test, men produced greater peak and average relative power. No differences in flexibility were observed. In the single kick test, seniors kicked faster than less experienced athletes (200.6 ± 12.3m / s versus 258 ± 5.6m / s, p <0.001) and performed greater number of kicks in the 21s, 6 ± 2.1 reps versus 15.5 ± 0.7 reps, p <0.001). It was concluded that there are differences between male and female TKD athletes regarding anthropometric and motor characteristics, and that more experienced athletes exhibit greater general and specific physical fitness.

Resumo O objetivo desta investigação foi mensurar variáveis antropométricas e de desempenho físico de atletas de TKD da cidade de Pelotas - RS. Foram avaliados 45 atletas com idades 16,4±5,2 anos e tempo de prática de 3,25± 3,6 anos. Os atletas realizaram avaliação antropométrica, testes de desempenho físico, gerais e específicos. No somatório de sete dobras cutâneas, homens apresentam menores valores (106,1±49,5mm versus 143,4±43,2mm; p<0,002). Homens mais graduados apresentaram melhor desempenho no salto vertical que homens iniciantes (42,3±8,5cm versus 24,8±10,1cm; p<0,03) e que mulheres (22,1±4,3cm; p<0,03). Indivíduos graduados realizam maior número de flexões de cotovelo que iniciantes e mulheres e mais repetições no teste de abdominais. Atletas da categoria sênior e júnior masculino exibiram mais força isométrica de preensão manual que as mulheres (48,3±3,9kgf e 38,1±12,6kgf versus 29±5,6kgf; p<0,001). Homens percorreram maior distância no yo-yo test que mulheres (606,6±233,8m versus 200±113,1m; p<0,001). No teste de Wingate, homens produziram maior potência relativa máxima e média. Não foram observadas diferenças na flexibilidade. No teste de chute único, indivíduos mais graduados chutaram mais rápido do que os menos graduados (200,6±12,3m/s versus 258±5,6m/s; p<0,001) e executam maior número de chutes em 10s (21,6±2,1reps versus 15,5±0,7reps; p<0,001). Conclui-se que há diferenças entre homens e mulheres praticantes de TKD quanto a características antropométricas e motoras, e que atletas mais avançados exibem maior aptidão física geral e específica.

Resistance Exercise Selectively Mobilizes Monocyte Subsets: Role of Polyphenols.

PURPOSE: To examine the impact of polyphenol supplementation on the recruitment, mobilization, and activation of monocyte subsets after resistance exercise. METHODS: Thirty-eight recreationally active males (22.1 ± 3.1 yr; 173.9 ± 7.9 cm; 77.8 ± 14.5 kg) were assigned to 28 d of polyphenol blend (PPB) supplementation, placebo (PL), or control (CON). Blood samples were obtained before (PRE) postresistance exercise, immediately (IP) postresistance exercise, 1 h (1H) postresistance exercise, 5 h (5H) postresistance exercise, 24 h (24H) postresistance exercise, and 48 h (48H) postresistance exercise (PPB/PL) or rest (CON). Fine-needle biopsies were obtained from the vastus lateralis at PRE, 1H, 5H, and 48H. Circulating concentrations of macrophage chemoattractant protein-1 (MCP-1) and fractalkine, as well as intramuscular MCP-1 were analyzed via multiplex assay. Changes in the proportions and expression of CD11b on monocyte subsets were assessed via flow cytometry. RESULTS: Circulating MCP-1 increased in PPB and PL at IP with further increases at 5H. Intramuscular MCP-1 was increased at 1H, 5H, and 48H in all groups. Classical monocyte proportions were reduced in PPB and PL at IP, and increased at 1H. Nonclassical monocytes were increased in PPB and PL at IP, whereas intermediate monocytes were increased at IP, and reduced at 1H. Intermediate monocytes were increased in PPB at 24H and 48H. CD11b expression was reduced on PPB compared with PL and CON at PRE on intermediate and nonclassical monocytes. CONCLUSIONS: Resistance exercise may elicit selective mobilization of intermediate monocytes at 24H and 48H, which may be mediated by tissue damage. Additionally, polyphenol supplementation may suppress CD11b expression on monocyte subsets at rest.

Androgens induce growth of the limb skeletal muscles in a rapamycin-insensitive manner.

Signaling through the mechanistic target of rapamycin complex 1 (mTORC1) has been well defined as an androgen-sensitive transducer mediating skeletal muscle growth in vitro; however, this has yet to be tested in vivo. As such, male mice were subjected to either sham or castration surgery and allowed to recover for 7 wk to induce atrophy of skeletal muscle. Then, castrated mice were implanted with either a control pellet or a pellet that administered rapamycin (~2.5 mg·kg-1·day-1). Seven days postimplant, a subset of castrated mice with control pellets and all castrated mice with rapamycin pellets were given once weekly injections of nandrolone decanoate (ND) to induce muscle growth over a six-week period. Effective blockade of mTORC1 by rapamycin was noted in the skeletal muscle by the inability of insulin to induce phosphorylation of ribosomal S6 kinase 1 70 kDa (Thr389) and uncoordinated-like kinase 1 (Ser757). While castration reduced tibialis anterior (TA) mass, muscle fiber cross-sectional area, and total protein content, ND administration restored these measures to sham levels in a rapamycin-insensitive manner. Similar findings were also observed in the plantaris and soleus, suggesting this rapamycin-insensitive effect was not specific to the TA or fiber type. Androgen-mediated growth was not due to changes in translational capacity. Despite these findings in the limb skeletal muscle, rapamycin completely prevented the ND-mediated growth of the heart. In all, these data indicate that mTORC1 has a limited role in the androgen-mediated growth of the limb skeletal muscle; however, mTORC1 was necessary for androgen-mediated growth of heart muscle.

Polyphenol supplementation alters intramuscular apoptotic signaling following acute resistance exercise.

The purpose of this study was 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. Untrained males (n = 38, 21.8 ± 2.7 years, 173.4 ± 7.9 cm, 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 resistance exercise protocol comprised of the squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis preexercise (PRE), 1-h (1HR), 5-h (5HR), and 48-h (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). Changes in markers of muscle damage and intramuscular signaling were analyzed via separate repeated measures analysis of variance (ANOVA). Change in Bcl-2 phosphorylation at 1H was significantly greater in PL compared to CON (P = 0.001). BAD phosphorylation was significantly elevated at 5H in PL compared to PPB (P = 0.015) and CON (P = 0.006). The change in JNK phosphorylation was significantly greater in PPB (P = 0.009), and PL (P = 0.017) compared to CON at 1H, while the change for PL was elevated compared to CON at 5H (P = 0.002). A main effect was observed (P < 0.05) at 1H, 5H, and 48H for p53 and Caspase 8, with Caspase 3 and Caspase 9 elevated at 48H. These data indicate that chronic supplementation with PPB alters apoptotic signaling in skeletal muscle following acute muscle-damaging resistance exercise.

Tumor necrosis factor-alpha and soluble TNF-alpha receptor responses in young vs. middle-aged males following eccentric exercise.

BACKGROUND: Tumor necrosis factor-alpha (TNF-α) has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF-α is responsible for the age-related losses in muscle size and function. Also, due to the high clearance rate of TNF-α from circulation, analyzing the circulating levels of soluble TNF-α receptors 1 and 2 (STNFR1 and STNFR2) may provide a better indication of inflammatory events. The aim of this study was to examine changes in circulating concentrations of TNF-α, STNFR1, and STNFR2 following acute eccentric exercise in young (YA) and middle-aged (MA) men. METHODS AND MATERIALS: Nine YA (N=9, 21.8±2.2y, 179.5±4.9cm, 91.2±12.2kg, 21.8±4.3% body fat) and ten MA (N=10, 47.0±4.4y, 176.8±7.6cm; 96.0±21.5kg, 25.4±5.3% body fat) men completed an acute muscle damaging protocol (MDP). Blood samples were obtained at baseline (BL), immediately (IP), 30-minute (30P), 60-minute (60P), 120-minute (120P), 24-hour (24H), and 48-hour (48H) post-MDP. Lower body performance was assessed via isokinetic dynamometer at BL, IP, 120P, 24H, and 48H. RESULTS: YA displayed higher values of peak torque (p=0.023) and mean torque (p=0.036) at BL. No significant group differences were observed for markers of muscle damage or TNF-α. Plasma concentrations of TNF-α were unchanged following MDP. STNFR1 concentrations were significantly higher in the YA group compared to MA (p=0.036). Significant time effects were observed for STNFR1 (p<0.001) and STNFR2 (p=0.001). With both groups combined, serum STNFR1 was decreased at 30P (p=0.001), while STNFR2 was decreased at 30P (p=0.008), 60P (p=0.003), and 120P (p=0.002) relative to BL. CONCLUSIONS: The pro-inflammatory response to muscle damage does not appear to decline at middle age when individuals are recreationally trained. However, young men showed significantly higher serum STNFR1 concentrations than middle age men. This may suggest that natural inhibitors of TNF-α decline as early as middle age.

Impact of Polyphenol Supplementation on Acute and Chronic Response to Resistance Training.

Beyer, KS, Stout, JR, Fukuda, DH, Jajtner, AR, Townsend, JR, Church, DD, Wang, R, Riffe, JJ, Muddle, TWD, Herrlinger, KA, and Hoffman, JR. Impact of polyphenol supplementation on acute and chronic response to resistance training. J Strength Cond Res 31(11): 2945-2954, 2017-This study investigated the effect of a proprietary polyphenol blend (PPB) on acute and chronic adaptations to resistance exercise. Forty untrained men were assigned to control, PPB, or placebo. Participants in PPB or placebo groups completed a 4-week supplementation period (phase I), an acute high-volume exercise bout (phase II), and a 6-week resistance training program (phase III); whereas control completed only testing during phase II. Blood draws were completed during phases I and II. Maximal strength in squat, leg press, and leg extension were assessed before and after phase III. The exercise protocol during phase II consisted of squat, leg press, and leg extension exercises using 70% of the participant's strength. The resistance training program consisted of full-body exercises performed 3 d·wk. After phase I, PPB (1.56 ± 0.48 mM) had greater total antioxidant capacity than placebo (1.00 ± 0.90 mM). Changes in strength from phase III were similar between PPB and placebo. Polyphenol blend supplementation may be an effective strategy to increase antioxidant capacity without limiting strength gains from training.

Comparison of Two ß-Alanine Dosing Protocols on Muscle Carnosine Elevations.

OBJECTIVE: ß-alanine (BA) is a nonproteogenic amino acid that combines with histidine to form carnosine. The amount taken orally in individual doses, however, is limited due to symptoms of paresthesia that are associated with higher doses. The use of a sustained-release formulation has been reported to reduce the symptoms of paresthesia, suggesting that a greater daily dose may be possible. The purpose of the present study was to determine whether increasing the daily dose of BA can result in a similar increase in muscle carnosine in a reduced time. METHODS: Eighteen men and twelve women were randomized into either a placebo (PLC), 6-g BA (6G), or 12-g BA (12G) groups. PLC and 6G were supplemented for 4 weeks, while 12G was supplemented for 2 weeks. A resting blood draw and muscle biopsy were obtained prior to (PRE) and following (POST) supplementation. Plasma and muscle metabolites were measured by high-performance liquid chromatography. The loss in peak torque (ΔPT) was calculated from maximal isometric contractions before and after 250 isokinetic kicks at 180°·sec-1 PRE and POST. RESULTS: Both 12G (p = 0.026) and 6G (p = 0.004) increased muscle carnosine compared to PLC. Plasma histidine was decreased from PRE to POST in 12G compared to PLC (p = 0.002) and 6G (p = 0.001), but no group x time interaction (p = 0.662) was observed for muscle histidine. No differences were observed for any hematological measure (e.g., complete blood counts) or in symptoms of paresthesia among the groups. Although no interaction was noted in ΔPT, a trend (p = 0.073) was observed. CONCLUSION: Results of this investigation indicate that a BA supplementation protocol of 12 g/d-1, using a sustained-release formulation, can accelerate the increase in carnosine content in skeletal muscle while attenuating paresthesia.

Comparisons in the Recovery Response From Resistance Exercise Between Young and Middle-Aged Men.

Gordon, JA III, Hoffman, JR, Arroyo, E, Varanoske, AN, Coker, NA, Gepner, Y, Wells, AJ, Stout, JR, and Fukuda, DH. Comparisons in the recovery response from resistance exercise between young and middle-aged men. J Strength Cond Res 31(12): 3454-3462, 2017-The purpose of this study was to compare the effects of a bout of high-volume isokinetic resistance exercise protocol (HVP) on lower-body strength and markers of inflammation and muscle damage during recovery between young and middle-aged adult men. Nineteen recreationally trained men were classified as either a young adult (YA: 21.8 ± 2.0 years; 90.7 ± 11.6 kg) or a middle-aged adult (MA: 47.0 ± 4.4 years; 96.0 ± 21.5 kg) group. The HVP consisted of 8 sets of 10 repetitions, with 1 minute of rest between each set, performed on an isokinetic dynamometer at 60°·s. Maximal voluntary isometric contractions and isokinetic peak torque (PKT) and average torque (AVGT) (measured at 240° and 60°·s, respectively) were assessed at baseline (BL), immediately post (IP), 120 minutes, 24, and 48 hours after HVP. Blood was obtained at BL, IP, 30, 60, 120 minute, 24, and 48 hours after HVP to assess muscle damage and inflammation. All performance data were analyzed using repeated measures analysis of covariance, whereas all inflammatory and muscle damage markers were analyzed using a 2-way (time × group) repeated measures analysis of variance. Results revealed no between-group differences for PKT, AVGT, or rate of torque development at 200 ms (RTD200). No between-group differences in myoglobin, creatine kinase, C-reactive protein, or interleukin-6 were observed. Although BL differences in muscle performance were observed between YA and MA, no between-group differences were noted in performance recovery measures from high-volume isokinetic exercise in recreationally trained men. These results also indicate that the inflammatory and muscle damage response from high-volume isokinetic exercise is similar between recreationally trained, young, and middle-aged adult men.

Post-resistance exercise ingestion of milk protein attenuates plasma TNFα and TNFr1 expression on monocyte subpopulations.

Attenuating TNFα/TNFr1 signaling in monocytes has been proposed as a means of mitigating inflammation. The purpose of this study was to examine the effects of a milk protein supplement on TNFα and monocyte TNFr1 expression. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) ingested supplement (SUPP) or placebo (PL) immediately post-exercise in a randomized, cross-over design. Blood samples were obtained at baseline (BL), immediately (IP), 30-min (30P), 1-h (1H), 2-h (2H), and 5-h (5H) post-exercise to assess plasma concentrations of myoglobin; tumor necrosis factor-alpha (TNFα); and expression of tumor necrosis factor receptor 1 (TNFr1) on classical, intermediate, and non-classical monocytes. Magnitude-based inferences were used to provide inferences on the true effects of SUPP compared to PL. Plasma TNFα concentrations were "likely attenuated" (91.6% likelihood effect) from BL to 30P in the SUPP group compared with PL (d = 0.87; mean effect: 2.3 ± 2.4 pg mL-1). TNFr1 expressions on classical (75.9% likelihood effect) and intermediate (93.0% likelihood effect) monocytes were "likely attenuated" from BL to 2H in the SUPP group compared with PL (d = 0.67; mean effect: 510 ± 670 RFU, and d = 1.05; mean effect: 2500 ± 2300 RFU, respectively). TNFr1 expression on non-classical monocytes was "likely attenuated" (77.6% likelihood effect) from BL to 1H in the SUPP group compared with PL (d = 0.69; mean effect: 330 ± 430 RFU). Ingestion of a milk protein supplement immediately post-exercise appears to attenuate both plasma TNFα concentrations and TNFr1 expression on monocyte subpopulations in resistance-trained men.

Castration alters protein balance after high-frequency muscle contraction.

Resistance exercise increases muscle mass by shifting protein balance in favor of protein accretion. Androgens independently alter protein balance, but it is unknown whether androgens alter this measure after resistance exercise. To answer this, male mice were subjected to sham or castration surgery 7-8 wk before undergoing a bout of unilateral, high-frequency, electrically induced muscle contractions in the fasted or refed state. Puromycin was injected 30 min before euthanasia to measure protein synthesis. The tibialis anterior was analyzed 4 h postcontraction. In fasted mice, neither basal nor stimulated rates of protein synthesis were affected by castration despite lower phosphorylation of mechanistic target of rapamycin in complex 1 (mTORC1) substrates [p70S6K1 (Thr389) and 4E-BP1 (Ser65)]. Markers of autophagy (LC3 II/I ratio and p62 protein content) were elevated by castration, and these measures remained elevated above sham values after contractions. Furthermore, in fasted mice, the protein content of Regulated in Development and DNA Damage 1 (REDD1) was correlated with LC3 II/I in noncontracted muscle, whereas phosphorylation of uncoordinated like kinase 1 (ULK1) (Ser757) was correlated with LC3 II/I in the contracted muscle. When mice were refed before contractions, protein synthesis and mTORC1 signaling were not affected by castration in either the noncontracted or contracted muscle. Conversely, markers of autophagy remained elevated in the muscles of refed, castrated mice even after contractions. These data suggest the castration-mediated elevation in baseline autophagy reduces the absolute positive shift in protein balance after muscle contractions in the refed or fasted states. NEW & NOTEWORTHY: In the absence of androgens, markers of autophagy were elevated, and these could not be normalized by muscle contractions. In the fasted state, REDD1 was identified as a potential contributor to autophagy in noncontracted muscle, whereas phosphorylation of ULK1 may contribute to this process in the contracted muscle. In the refed state, markers of autophagy remain elevated in both noncontracted and contracted muscles, but the relationship with REDD1 and ULK1 (Ser757) no longer existed.

Monocyte Recruitment after High-Intensity and High-Volume Resistance Exercise.

UNLABELLED: The innate immune response is generally considered to have an important role in tissue remodeling after resistance exercise. PURPOSE: The purpose of this study was to compare changes in markers of monocyte recruitment after an acute bout of high-intensity (HVY) versus high-volume (VOL) lower-body resistance exercise. METHODS: Ten resistance-trained men (24.7 ± 3.4 yr, 90.1 ± 11.3 kg, 176.0 ± 4.9 cm) performed each protocol in a randomized, counterbalanced order. Blood samples were collected at baseline, immediately (IP), 30 min (30P), 1 h (1H), 2 h (2H), and 5 h (5H) postexercise. Plasma concentrations of monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor alpha (TNF-α), myoglobin, and cortisol were measured via assay. Tumor necrosis factor receptor 1 (TNFr1), macrophage-1 antigen (cluster of differentiation 11b [CD11b]), and C-C chemokine receptor 2 (CCR2) expression levels were measured using flow cytometry. TNFr1 and CD11b were assessed on CD14CD16 monocytes, whereas CCR2 was assessed on CD14 monocytes. RESULTS: Plasma myoglobin concentrations were significantly greater after HVY compared with VOL (P < 0.001). Changes in plasma TNF-α, MCP-1, and expression levels of CCR2 and CD11b were similar between HVY and VOL. When collapsed across groups, TNF-α was significantly increased at IP, 30P, 1H, and 2H (P values < 0.05), whereas MCP-1 was significantly elevated at all postexercise time points (P values < 0.05). CCR2 expression on CD14 monocytes was significantly lower at IP, 1H, 2H, and 5H (P values < 0.05). CD11b expression on CD14 CD16 was significantly greater at IP (P < 0.014) and 1H (P = 0.009). TNFr1 expression did not differ from baseline at any time point. Plasma cortisol concentrations did not seem to be related to receptor expression. CONCLUSIONS: Results indicate that both HVY and VOL protocols stimulate a robust proinflammatory response. However, no differences were noted between resistance exercise training paradigms.

A Microbiopsy Method for Immunohistological and Morphological Analysis: A Pilot Study.

INTRODUCTION: The fine aspiration microbiopsy is a relatively new biopsy technique, which allows muscle physiologists to sample skeletal muscle less invasively. However, the small sample size obtained is often deemed insufficient for certain analyses. The aim of the current study was to develop procedures for muscle fiber morphology and immunohistological analysis from a microbiopsy technique. METHODS: Microbiopsies of the vastus lateralis were taken with a 14-gauge microbiopsy needle from four healthy men on two separate occasions. The tissue was oriented in a cryomold, embedded in Tissue-Tek® then frozen in liquid nitrogen cooled isopentane. The muscle sections were stained with hematoxylin and eosin, laminin, MHCI, MHCIIa, and Pax7 for fiber number, mean fiber area, muscle fiber typing, and satellite cell observation. RESULTS: The mean ± SD (range) microbiopsy sample weight was 18.3 ± 2.9 mg (14-22 mg). The mean fiber number within the microbiopsy specimens was 150.4 ± 120.6 (64-366). All viable fibers were measured in each sample, and the mean fiber area was 4385.1 ± 1265.8 µm2 (977.0-10,132.93 µm2). There was no significant time difference (P = 0.69) in mean fiber area. DISCUSSION: Results suggest the potential use of a "minimally invasive" muscle biopsy technique for immunohistological and morphological analysis. This could provide clinicians and investigators additional data in future research. Further investigations are needed to determine the usefulness and potential limiting factors of this technique.