High-intensity eccentric exercise is known to cause skeletal muscle damage and microstructural changes to muscle tissue with an associated inflammatory response. Previous research demonstrates increased pro-inflammatory cytokine and prostaglandin concentrations are linked with perceived muscle soreness. The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), commonly found in fish oil supplements, exhibit anti-inflammatory properties that have been reported to attenuate the overall perception of muscle soreness. PURPOSE: To investigate the dose-response effect of fish oil (FO) supplementation on the magnitude and time-course of post-eccentric resistance exercise muscle soreness. METHODS: Thirty-two, college-aged, resistance-trained males (n = 16; 23.8 ± 2.7 years, 81.5 ± 9.9 kg, 175.7 ± 4.5 cm, 16.3 ± 3.6 %) and females (n = 16; 23.4 ± 3.1 years, 61.7 ± 7.2 kg, 170.4 ± 6.2 cm, 23.6 ± 5.0 %) completed a double-blind placebo controlled 7-week supplementation period of either: 2.0, 4.0, or 6.0 g·d-1 FO or placebo (PL). Subsequently, participants completed a muscle damaging resistance exercise protocol (10 sets of 8 four-second eccentric squats at 70% one-repetition maximum and 5 sets of 20 split-squat jumps). Perceived muscle soreness (PS; 0–10 cm scale) was measured pre-exercise (PRE), immediately post (IP), as well as 1, 2, 4, 24, 48, and 72 hours (h) post-exercise. RESULTS: Repeated measures analysis of variance revealed a group x time interaction for PS (p < 0.001), where compared to PL, lower PS scores were observed at IP for 6 g·d-1 (mean difference: 4.0 cm, p = 0.024), at 1h for 6 g·d-1 (mean difference: 2.74 cm, p = 0.046), at 24h for 4 g·d-1 (mean difference: 2.38 cm, p = 0.023), and 6 g·d-1 (mean difference: 3.45 cm, p < 0.001), at 48h for 6 g·d-1 (mean difference: 4.45 cm, p < 0.001), and at 72h for 6 g·d-1 (mean difference: 3.0 cm, p = 0.003). Other group differences were variable by time point. CONCLUSIONS: These data indicate that supplementation with 6 g·d-1 of FO is effective at attenuating PS following damaging eccentric resistance exercise for up to 72h. Supported by the International Society of Sports Nutrition and MusclePharm Grant
Background and Purpose: Rate of force development (RFD) is influential, and possibly more influential than other muscular performance parameters, for mobility in older adults. However, only a few studies have investigated this matter, and this has not been examined for the plantar flexors (PFs). The purpose of this study was to examine the contribution of PF RFD and other common tests of muscular performance to Up-and-Go (UG) performance and walking speed (WS) in older adults. Methods: Twenty-six (19 females) healthy, community-dwelling older adults (73.7 ± 4.9 years) were recruited from a senior citizen center for this observational study. Handgrip strength, UG performance, as well as preferred and maximal WS were obtained. Time taken to complete 5-chair rises and the number of chair rises completed in 30 seconds were recorded. Rate of force development of the PFs was obtained during a rapid, bilateral calf raise performed on a force plate. Hierarchical multiple linear regression was used to identify significant predictors, after adjusting for physical activity level and body mass index, of mobility (ie, UG, preferred and maximal WS). Results and Discussion: No muscular performance variables correlated with preferred WS. Rate of force development (adjusted R 2 = 0.356; P = .008) and handgrip strength (adjusted R 2 = 0.293; P = .026) were the only predictors of maximal WS and accounted for a 21.7% and 16.1% change in R 2 , respectively, after accounting for physical activity level and body mass index. Rate of force development was the only predictor of UG performance (adjusted R 2 = 0.212; P = .006) and accounted for a 29.2% change in R 2 after adjustment variables were applied. Conclusions: Compared to common assessments of muscular performance, such as handgrip strength and chair rise performance, PF RFD was a greater predictor of mobility in older adults. These findings, in conjunction with recent reports, indicate that the assessment of RFD likely complements strength testing, thereby enabling a more robust assessment of functional decline in older adults.
Osteoporosis causes bone fragility, increasing the risk of fractures. Evidence suggests a strong correlation between obesity and fracture risk. Physical training is known to enhance bone resistance and protect from fracture; however, its osteogenic effect in the presence of obesity remains unknown.We sought to evaluate the influence of exercise training on bone health indices in individuals with obesity.This systematic literature search was conducted using common electronic databases from inception - December 2019. The following key terms (and synonyms searched for by the MeSH database) were included and combined using the operators "AND," "OR," "NOT": [("body mass index" OR obesity OR obese OR overweight OR fat mass) AND ("bone mineral density" OR "bone mineral content" OR "peak bone mass" OR "mechanical loading" OR "Osteoporosis" OR "bone geometry" OR "bone resistance") AND ("exercise training" OR "physical training" OR "strength training," OR "resistance training" OR "aerobic training" OR "combined training")].After screening, 10 studies (889 initial records) were included in the final analysis (8 different countries, 263 participants). Two studies investigated males, six females, and two, both sexes. The training duration was at least eight weeks with 2-3 sessions/week. Physical training displayed a significant trivial impact on the whole body (WB) BMD (0.13 SMD; 95% CI [0.00, 0.26], p = 0.046). Subgroup analyses indicated a significant small increase in the WB BMD (0.27 SMD; 95% CI [0.00, 0.53], p = 0.048) in the endurance training group, a non-significant trivial increase in the WB BMD (0.11 SMD; 95% CI [-0.06, 0.29], p = 0.203) in the resistance group, and a non-significant trivial increase in the WB BMD (0.03 SMD; 95% CI [-0.26, 0.32], p = 0.86) in the combined training group. In addition, a significant small decrease was found in the weight of trained subjects (-0.24 SMD; 95% CI [-0.42, -0.05], p = 0.011).Physical training has little to no effect on the WB BMD in subjects with overweight/obesity. Currently, insufficient evidence to advocate for any specific type of exercise for enhancing bone health exists for overweight/obese individuals. Investigations examining the impact of varying types of physical exercise on WB BMD of obese individuals are needed.
Methylliberine (Dynamine; DYM) and theacrine (Teacrine; TCR) are purine alkaloids. Previous research on TCR reported increases in feelings of energy, focus, and concentration, and decreases in fatigue. Currently, there are no published human safety data on DYM. PURPOSE: The purpose of this study was to examine the effect of four weeks of DYM supplementation with and without TCR on blood biomarkers. METHODS: One-hundred twenty-five men (n = 60) and women (n = 65) were assigned to one of five groups: low dose DYM (100 mg), high dose DYM (150 mg), low dose DYM with TCR (100 mg + 50 mg), high dose DYM with TCR (150 mg + 25 mg) , and 125 mg maltodextrin. Participants visited the laboratory fasted on two occasions (week 0 and week 4), separated by four weeks of supplementation, for a blood draw. Blood was analyzed by an independent third-party (i.e. LabCorp). RESULTS: Three-way repeated measures analyses of variance were performed for all blood biomarkers. Group × sex × time interactions (p < 0.05) with post-hoc analyses revealed differences for mean corpuscular hemoglobin (MCH) concentration with MCH being higher in men consuming the placebo than women consuming low dose DYM (p = 0.028) and high dose DYM with TCR (p = 0.011) at week 4. Group × time interactions (p < 0.05) revealed differences for platelets, blood urea nitrogen, total globulins, alanine transaminase, total proteins, triglycerides, and high-density lipoproteins. However, post-hoc analyses showed specific increases for blood urea nitrogen in groups consuming low dose DYM with TCR compared to low dose DYM participants, and an increase in high-density lipoproteins in the group consuming high dose DYM. Significant main effects for time were observed. Specifically, increases in mean corpuscular volume, MCH, basophils, absolute eosinophils, creatinine, and high-density lipoproteins from week 0 to week 4, while decreases in glomerular filtration rate, chloride, carbon dioxide, bilirubin, and alanine transaminase were seen. CONCLUSIONS: While small changes were found in some biomarkers, in all cases values remained within normal clinical limits. This suggests that DYM alone or in combination with TCR consumed at the dosages used in this study does not appear to negatively impact blood biomarkers associated with health. Compound Solutions, Inc. grant
Proteases are enzymes which aid in the hydrolysis of proteins. Previous work has demonstrated protease supplementation may enhance recovery after high-intensity exercise by decreasing muscle damage and inflammation. While the mechanisms involved are not fully understood, it has been suggested that protease supplementation may alter the endocrine response to exercise, promoting a more favorable recovery state. PURPOSE: To determine if protease supplementation immediately after an exercise session influences circulating testosterone, cortisol, insulin, insulin-like growth factor-1 (IGF-1), and growth hormone (GH) concentrations. METHODS: Ten resistance trained males (24.1±4.1yr, 69.6±6.8 kg 179±8.6 cm) completed 3 acute lower-body resistance exercise sessions consisting of 4 sets of leg press and leg extension in a randomized, crossover fashion. Each exercise was performed at 75% of participant’s previously determined one repetition maximum, for 8-10 repetitions, with 90 seconds of rest between sets. Following the exercise session, participants consumed one of 3 treatments (W: 26g whey; PW: 26g whey + 250mg of a protease enzyme blend; PL: non-caloric control). Blood draws were obtained at baseline (BL), immediately-post (IP), 1-hour (1H) and 3-hours post-exercise (3H) and analyzed for testosterone, cortisol, insulin, IGF-1, and GH. Data for each hormone were analyzed with a 2-way repeated measures analysis of variance (ANOVA), while area under the curve (AUC) values were analyzed with a one-way ANOVA. RESULTS: Significant main effects for time (p<0.05) were observed for all hormones. There was a significant decrease in testosterone at IP (p=0.007), 1H (p<0.001), and 3H (p<0.001). There was a significant decrease in cortisol at all time points (p<0.001) compared to BL. There were significant increases in insulin, IGF-1, and growth hormone at all time points (p<0.001) following exercise. Additionally, no interaction for any hormone concentrations or AUC values were seen between treatments in this study. CONCLUSION: There were no differential effects of W or PW on the post-exercise endocrine response compared to PL. Therefore, neither protease nor protein supplementation appear to alter endocrine response to resistance exercise in trained males. Supported by Deerland Enzymes, Kennesaw, GA
Few studies have concurrently examined multiple rapid neuromuscular characteristics of the plantar flexors (PFs) in middle-aged (MM) and older (OM) males. Further, it is important to determine the association between these measures and physical function. PURPOSE:To compare rapid neuromuscular parameters of the PFs in MM and OM, and examine correlates of physical functioning. METHODS:Twenty-nine healthy, MM (n=14; 45.3±2.6 yrs) and OM (n=15; 65.3±3.2 yrs) performed fast, isotonic (IT) contractions with a load of 0.5 Nm and slow, isokinetic (IK; 60°·s-1) concentric contractions of the PFs using a dynamometer. Participants were instructed to push with the ball of their foot “as hard and fast as possible” prior to each contraction. Peak velocity (PV), rate of velocity development (RVDIT), and rate of electromyography rise (RER) were obtained from IT trials. During the IK trials, time to peak torque (TPT) and rate of velocity development (RVDIK) were acquired. RVD was obtained from the linear slope of the velocity-time curve (Δvelocity/Δtime)as the highest rolling 20 ms value. RER of the medial gastrocnemius was derived from the linear slope of the normalized electromyography signal as the highest rolling 50 ms value. Maximal walking velocity (MWV) and time to complete 5 chair rises (5CR) were also recorded. Group comparisons were made with independent samples t-tests, while Pearson correlation coefficients were calculated to examine select relationships. RESULTS:RVDITwas lower (MM=5202.83±510.23 vs. OM=4630.29±854.23°·s-2; p=0.037), and 5CR time greater (16%; p=0.022) in OM.RER was only correlated (r=0.431; p=0.026) with RVDIT. Only PV (r=0.396; p=0.033) and RVDIT(r=0.480;p=0.008) were correlated with MWV, while only TPT was correlated with 5CR time (r=0.451; p=0.014). CONCLUSIONS:Our findings suggest that rapid neuromuscular measures may be differentially influenced by age, and only particular parameters are associated with physical function.
Based on a comprehensive review and critical analysis of the literature regarding the nutritional concerns of female athletes, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Female athletes have unique and unpredictable hormone profiles, which influence their physiology and nutritional needs across their lifespan. To understand how perturbations in these hormones affect the individual, we recommend that female athletes of reproductive age should track their hormonal status (natural, hormone driven) against training and recovery to determine their individual patterns and needs and peri and post-menopausal athletes should track against training and recovery metrics to determine the individuals’ unique patterns. 2. The primary nutritional consideration for all athletes, and in particular, female athletes, should be achieving adequate energy intake to meet their energy requirements and to achieve an optimal energy availability (EA); with a focus on the timing of meals in relation to exercise to improve training adaptations, performance, and athlete health. 3. Significant sex differences and sex hormone influences on carbohydrate and lipid metabolism are apparent, therefore we recommend first ensuring athletes meet their carbohydrate needs across all phases of the menstrual cycle. Secondly, tailoring carbohydrate intake to hormonal status with an emphasis on greater carbohydrate intake and availability during the active pill weeks of oral contraceptive users and during the luteal phase of the menstrual cycle where there is a greater effect of sex hormone suppression on gluconogenesis output during exercise. 4. Based upon the limited research available, we recommend that pre-menopausal, eumenorrheic, and oral contraceptives using female athletes should aim to consume a source of high-quality protein as close to beginning and/or after completion of exercise as possible to reduce exercise-induced amino acid oxidative losses and initiate muscle protein remodeling and repair at a dose of 0.32–0.38 g·kg−1. For eumenorrheic women, ingestion during the luteal phase should aim for the upper end of the range due to the catabolic actions of progesterone and greater need for amino acids. 5. Close to the beginning and/or after completion of exercise, peri- and post-menopausal athletes should aim for a bolus of high EAA-containing (~10 g) intact protein sources or supplements to overcome anabolic resistance. 6. Daily protein intake should fall within the mid- to upper ranges of current sport nutrition guidelines (1.4–2.2 g·kg−1·day−1) for women at all stages of menstrual function (pre-, peri-, post-menopausal, and contraceptive users) with protein doses evenly distributed, every 3-4 h, across the day. Eumenorrheic athletes in the luteal phase and peri/post-menopausal athletes, regardless of sport, should aim for the upper end of the range. 7. Female sex hormones affect fluid dynamics and electrolyte handling. A greater predisposition to hyponatremia occurs in times of elevated progesterone, and in menopausal women, who are slower to excrete water. Additionally, females have less absolute and relative fluid available to lose via sweating than males, making the physiological consequences of fluid loss more severe, particularly in the luteal phase. 8. Evidence for sex-specific supplementation is lacking due to the paucity of female-specific research and any differential effects in females. Caffeine, iron, and creatine have the most evidence for use in females. Both iron and creatine are highly efficacious for female athletes. Creatine supplementation of 3 to 5 g per day is recommended for the mechanistic support of creatine supplementation with regard to muscle protein kinetics, growth factors, satellite cells, myogenic transcription factors, glycogen and calcium regulation, oxidative stress, and inflammation. Post-menopausal females benefit from bone health, mental health, and skeletal muscle size and function when consuming higher doses of creatine (0.3 g·kg−1·d−1). 9. To foster and promote high-quality research investigations involving female athletes, researchers are first encouraged to stop excluding females unless the primary endpoints are directly influenced by sex-specific mechanisms. In all investigative scenarios, researchers across the globe are encouraged to inquire and report upon more detailed information surrounding the athlete’s hormonal status, including menstrual status (days since menses, length of period, duration of cycle, etc.) and/or hormonal contraceptive details and/or menopausal status.