Effects of different HIIT protocols on exercise performance, metabolic adaptation, and fat loss in middle-aged and older adults with overweight.

Introduction: There is evidence that aging and obesity are associated with increased oxidative stress and chronic inflammation. High-intensity interval training (HIIT) may be superior to moderate-intensity continuous training (MICT) in anti-inflammatory and anti-obesity benefits. Therefore, the objective of this study is to determine which HIIT prescriptions will be more effective in reducing fat accumulation, inflammation, and improving metabolic adaptation and exercise performance in middle-aged and older overweight adults. Methods: Thirty-six middle-aged with overweight adults were divided into one of three groups: 1. L-HIIT group: the long-interval HIIT group (4 × 4 min Exercise/4 min Rest), 2. M-HIIT group: the medium-interval HIIT group (8 × 2 min Exercise/2 min Rest), 3. Control group: no exercise training intervention. All groups underwent the training stage for eight weeks (three sessions per week), followed by a detraining stage of four weeks in order to investigate the effects induced by different HIIT interventions on inflammation, metabolic adaptation, anti-fatigue and exercise performance, and fat loss Results: There was a significant physiological response in the change rate of heart rate (HR) after an acute L-HIIT session compared with an acute M-HIIT session (ΔHR: ↑49.66±16.09% vs ↑33.22±14.37%, p=0.02); furthermore, systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased significantly following a single L-HIIT session. After an eight-week training stage, the L-HIIT and M-HIIT groups exhibited a significant increase in aerobic capacity (ΔVO2peak), with values of +27.93±16.79% (p<0.001) and +18.39±8.12% (p<0.001), respectively, in comparison to the control group. Furthermore, in the L-HIIT group, the anaerobic power of relative mean power (RMP) exhibited a significant increase (p=0.019). However, following a four-week detraining stage, the adiponectin concentration remained 1.78 times higher in the L-HIIT group than in the control group (p=0.033). The results of blood sugar, blood lipids, body composition, and inflammatory markers did not indicate any improved it did not indicate any improvements from the two different HIIT protocols. Conclusions: The results indicate that an eight-week L-HIIT or M-HIIT intervention (three sessions per week, 32 minutes per session) may be an effective approach for improving aerobic capacity. It can be posited that L-HIIT may be a more advantageous mode than M-HIIT for enhancing anaerobic power, adipokine levels, and improving blood pressure in an aged and overweight population due to the induced physiological responses.

Effects of Resveratrol on Muscle Inflammation, Energy Utilisation, and Exercise Performance in an Eccentric Contraction Exercise Mouse Model.

Eccentric contraction can easily cause muscle damage and an inflammatory response, which reduces the efficiency of muscle contraction. Resveratrol causes anti-inflammatory effects in muscles, accelerates muscle repair, and promotes exercise performance after contusion recovery. However, whether resveratrol provides the same benefits for sports injuries caused by eccentric contraction is unknown. Thus, we explored the effects of resveratrol on inflammation and energy metabolism. In this study, mice were divided into four groups: a control group, an exercise group (EX), an exercise with low-dose resveratrol group (EX + RES25), and an exercise with high-dose resveratrol group (EX + RES150). The results of an exhaustion test showed that the time before exhaustion of the EX + RES150 group was greater than that of the EX group. Tumour necrosis factor-α (Tnfα) mRNA expression was lower in the EX + RES150 group than in the EX group. The energy utilisation of the EX + RES150 group was greater than that of the EX + RES25 group in different muscles. High-dose resveratrol intervention decreased Tnfα mRNA expression and enhanced the mRNA expressions of sirtuin 1, glucose transporter 4, AMP-activated protein kinase α1, and AMP-activated protein kinase α2 in muscles. These results revealed that high-dose resveratrol supplementation can reduce inflammation and oxidation and improve energy utilisation during short-duration high-intensity exercise.

Effects of Acute Aquatic High-Intensity Intermittent Exercise on Blood Pressure and Arterial Stiffness in Postmenopausal Women with Different ACE Genotypes.

The present study investigated the effects of acute aquatic high-intensity intermittent jumping (HIIJ) on blood pressure (BP) and arterial stiffness in postmenopausal women with different angiotensin-converting enzyme genotypes (ACE). We recruited 12 postmenopausal women carrying the ACE deletion/deletion (DD) genotype and 61 carrying the insertion/insertion or insertion/deletion (II/ID) genotype. The participants performed 12 trials of 30 s, 75% heart rate reserve (HRR) jumping, and 60 s, 50% HRR recovery, and 3 trials of 40 s upper limb resistance exercises were performed as fast as possible. The heart rate (HR) and BP were measured before exercise, immediately, 10 min, and 45 min after exercise. The brachial-ankle pulse wave velocity (baPWV) was measured before and after exercise. The systolic blood pressure (SBP) of the DD genotype increased more significantly than those with the II/ID genotype post-exercise (30.8 ± 4.48 vs. 20.4 ± 2.00 mmHg, p = 0.038). The left and right sides of baPWV increased significantly after exercise (1444.8 ± 29.54 vs. 1473.4 ± 32.36 cm/s, p = 0.020; 1442.1 ± 30.34 vs. 1472.0 ± 33.09, p = 0.011), and there was no significant difference between the two groups. The HIIJ increased baPWV. The postmenopausal women with the DD genotype have a higher SBP increased post-exercise than those with II/ID genotype. These findings suggest that the aquatic exercise program has better effects in decreasing blood pressure in postmenopausal women with the II/ID genotype. Those with the DD genotype should pay attention to the risk of increasing blood pressure after aquatic HIIJ exercise.

Development and Validation of 3 Min Incremental Step-In-Place Test for Predicting Maximal Oxygen Uptake in Home Settings: A Submaximal Exercise Study to Assess Cardiorespiratory Fitness.

The purpose of this research was to develop the 3 min incremental step-in-place (3MISP) test for predicting maximal oxygen uptake (V.O2max). A total of 205 adults (20-64 years) completed the 3MISP and V.O2max tests. Using age, gender, body composition (BC) including percent body fat (PBF) or body mass index (BMI), and with or without heart rate (HR) at the beginning of exercise (HR0) or difference between HR at the third minute during the exercise and the first minute post exercise (ΔHR3 - HR4) in the 3MISP test, six V.O2max prediction models were derived from multiple linear regression. Age (r = -0.239), gender (r = 0.430), BMI (r = -0.191), PBF (r = -0.706), HR0 (r = -0.516), and ΔHR3 - HR4 (r = 0.563) were significantly correlated to V.O2max. Among the six V.O2max prediction models, the PBF model∆HR3 - HR4 has the highest accuracy. The simplest models with age, gender, and PBF/BMI explained 54.5% of the V.O2max in the PBF modelBC and 39.8% of that in the BMI modelBC. The addition of HR0 and ∆HR3 - HR4 increases the variance of V.O2max explained by the PBF and BMI models∆HR3 - HR4 by 17.98% and 45.23%, respectively, while standard errors of estimate decrease by 10.73% and 15.61%. These data demonstrate that the models established using 3MISP-HR data can enhance the accuracy of V.O2max prediction.

Protective and Recovery Effects of Resveratrol Supplementation on Exercise Performance and Muscle Damage following Acute Plyometric Exercise.

Plyometric exercise (PE) is an effective training method to increase muscle mass and strength. However, excessive or inappropriate conditions might cause exercise-induced muscle damage (EIMD). Resveratrol (RES) is a natural polyphenol plant antitoxin, which improves exercise performance, and exhibits anti-oxidation, anti-inflammatory, and anti-cancer effects. Therefore, this study investigated the effect of RES supplementation on the recovery of muscle damage, inflammation, soreness, muscle power, and anaerobic performance following plyometric-exercise-induced muscle damage (PEIMD). The present study was a double-blind, placebo-controlled research trial. Thirty-six young, untrained males were enrolled into the placebo (n = 12), RES-500 (500 mg RES/day, n = 12), or RES-1000 (1000 mg RES/day, n = 12) group by a jumping height-counterbalanced grouping design. At baseline, to pre-PEIMD, supplements were pre-loaded 7 days before they conducted PEIMD, and the exercise performance, delayed-onset muscle soreness (DOMS) and muscle damage biomarkers were measured over the experimental period at baseline, pre-PEIMD, and post-PEIMD at 2, 24, 48, and 72 h. As a result, we found that, at 72 h post-EIMD, the force peak (FP) and rate of force development (RFD) of the counter movement jump (CMJ) in RES groups showed no significant difference compared to that at baseline but was significantly greater than the placebo group. In the Wingate anaerobic test (WAnT), supplementation in the RES group had a better recovery effect on the relative peak power (RPP), relative mean power (RMP) and fatigue index (FI) (p < 0.05), especially in the high-dose group. For the detection of muscle pain after PEIMD, the RES supplement group was significantly better than the placebo group (p < 0.05). In addition, for muscle damage indexes, such as creatine kinase (CK) and lactate dehydrogenase (LDH), after PEIMD, supplementation with RES could significantly reduce and accelerate recovery (p < 0.05). In addition, the blood biochemical indicators of blood count, liver function, and kidney function showed that RES will not cause adverse risks to the human body. Our results suggest that replenishing RES in advance could effectively reduce muscle pain, increase exercise performance, and decrease muscle damage indicators caused by PEIMD, and the recovery was faster. Therefore, plyometric exercises combined with suitable RES supplementation could be an effective candidate for controlling muscle damage, improving physical adaption, and recovering anaerobic capacity.

Predicting maximal oxygen uptake from a 3-minute progressive knee-ups and step test.

BACKGROUND: Cardiorespiratory fitness assessment is crucial for diagnosing health risks and assessing interventions. Direct measurement of maximum oxygen uptake (V̇O2 max) yields more objective and accurate results, but it is practical only in a laboratory setting. We therefore investigated whether a 3-min progressive knee-up and step (3MPKS) test can be used to estimate peak oxygen uptake in these settings. METHOD: The data of 166 healthy adult participants were analyzed. We conducted a V̇O2 max test and a subsequent 3MPKS exercise test, in a balanced order, a week later. In a multivariate regression model, sex; age; relative V̇O2 max; body mass index (BMI); body fat percentage (BF); resting heart rate (HR0); and heart rates at the beginning as well as at the first, second, third, and fourth minutes (denoted by HR0, HR1, HR2, HR3, and HR4, respectively) during a step test were used as predictors. Moreover, R2 and standard error of estimate (SEE) were used to evaluate the accuracy of various body composition models in predicting V̇O2max. RESULTS: The predicted and actual V̇O2 max values were significantly correlated (BF% model: R2 = 0.624, SEE = 4.982; BMI model: R2 = 0.567, SEE = 5.153). The BF% model yielded more accurate predictions, and the model predictors were sex, age, BF%, HR0, ΔHR3-HR0, and ΔHR3-HR4. CONCLUSION: In our study, involving Taiwanese adults, we constructed and verified a model to predict V̇O2 max, which indicates cardiorespiratory fitness. This model had the predictors sex, age, body composition, and heart rate changes during a step test. Our 3MPKS test has the potential to be widely used in epidemiological research to measure V̇O2 max and other health-related parameters.

The Effect of Kefir Supplementation on Improving Human Endurance Exercise Performance and Antifatigue.

Kefir is an acidic, carbonated, and fermented dairy product produced by fermenting milk with kefir grains. The Lactobacillus species constitutes an important part of kefir grains. In a previous animal study, kefir effectively improved exercise performance and had anti-fatigue effects. The purpose of this research was to explore the benefits of applying kefir to improve exercise performance, reduce fatigue, and improve physiological adaptability in humans. The test used a double-blind crossover design and supplementation for 28 days. Sixteen 20-30 year-old subjects were divided into two groups in a balanced order according to each individual's initial maximal oxygen uptake and were assigned to receive a placebo (equal flavor, equal calories, 20 g/day) or SYNKEFIR™ (20 g/day) every morning. After the intervention, there were 28 days of wash-out, during which time the subjects did not receive further interventions. After supplementation with SYNKEFIR™, the exercise time to exhaustion was significantly greater than that before ingestion (p = 0.0001) and higher than that in the Placebo group by 1.29-fold (p = 0.0004). In addition, compared with the Placebo group, the SYNKEFIR™ administration group had significantly lower lactate levels in the exercise and recovery (p < 0.05). However, no significant difference was observed in the changes in the gut microbiota. Although no significant changes in body composition were found, SYNKEFIR™ did not cause adverse reactions or harm to the participants' bodies. In summary, 28 days of supplementation with SYNKEFIR™ significantly improved exercise performance, reduced the production of lactic acid after exercise, and accelerated recovery while also not causing any adverse reactions.

Land vs. water HIIE effects on muscle oxygenation and physiological parameter responses in postmenopausal women.

Muscle oxygenation (MO) status is the dynamic balance between O2 utilization and O2 delivery. Low-impact high-intensity interval exercise MO responses in the exercise and recovery stage are still unclear. We compared the differences in MO and physiological parameters between high-intensity interval water-based exercise (WHIIE) and high-intensity interval land bike ergonomic exercise (LBEHIIE) in postmenopausal women. Eleven postmenopausal women completed WHIIE or LBEHIIE in counter-balanced order. Eight sets were performed and each exercise set included high intensity with 80% heart rate reserve (HRR) in 30 s and dynamic recovery with 50% HRR in 90 s. Muscle tissue oxygen saturation index (TSI), total hemoglobin (tHb), oxy-hemoglobin (O2Hb), and deoxy-hemoglobin (HHb) were recorded. Blood lactate, heart rate and rating of perceived exertion (RPE) were measured at pre and post-exercise. Under similar exercise intensity, RPE in WHIIE was lower than that in LBEHIIE. The heart rate in WHIIE was lower than that in LBEHIIE at 1 and 2 min post-exercise. During the dynamic recovery, TSI, tHb, and O2Hb in water were higher than on land. A negative correlation was found between the change in TSI and lactate concentration (r = - 0.664). WHIIE produced greater muscle oxygenation during dynamic recovery. Muscle TSI% was inversely related to blood lactate concentration during exercise in water.

The Association between Physical Fitness Performance and Abdominal Obesity Risk among Taiwanese Adults: A Cross-Sectional Study.

The present study aims to investigate the associations between physical fitness performance and abdominal obesity risk among Taiwanese adults. We conducted a cross-sectional study and reviewed the data derived from the National Physical Fitness Survey in Taiwan (HPFSIT). Data from a total of 62,486 respondents aged 23-64 years were collected in this study. The participants completed a standardized structural questionnaire and a series of anthropometric characteristics (body mass index and waist-to-hip ratio) and physical fitness (3-min step tests, 1-min sit-up tests, and sit-and-reach tests) assessments. Waist circumference was used to define abdominal obesity status. A multiple logistic regression analysis was conducted. Our results presented almost entirely significant associations (except for women) on the 3-min step test. Moreover, the results suggest that muscular strength, endurance, and flexibility may be effective predictors of abdominal obesity among men and women, whereas cardiorespiratory fitness predicted abdominal obesity only in men. According to the results of this study, the fitness-abdominal obesity associations are minor based on a mixed population analysis. However, dose-response relationships have been observed. The present study provides a new perspective by using different types of fitness performance to predict abdominal obesity.

Protective Effects of Resveratrol Supplementation on Contusion Induced Muscle Injury.

Muscle injuries frequently occur in contact sports events. The current treatment options for soft tissue injuries remain suboptimal and often result in delayed or incomplete recovery of damaged muscles. Resveratrol (RES) is a phenolic phytochemical, well-known for its antioxidant and anti-inflammatory properties. The purpose of this study is to evaluate the potential beneficial effects of RES supplementation on inflammation and regeneration in skeletal muscle after a contusion injury, in comparison to a conventional treatment of nonsteroidal anti-inflammatory drugs (NSAID). After one week of acclimation, forty eight -week-old male ICR mice were randomly divided into the five groups (n=8 per group): 1) normal control (NC), 2) mass-drop injury without any treatment (mass-drop injury, MDI), 3) post-injury NSAID treatment (MDI+ 10mg/kg NSAID), 4) post-injury RES supplementation (MDI+ 25mg/kg/day RES) and 5) post-injury treatment with RES and NSAID (MDI + resveratrol+ NSAID). After muscle contusion injury of the left gastrocnemius muscle, RES or NSAID were orally administered post-injury once a day for 7 days. Results showed that the MDI group had significantly higher serum uric acid (UA), CREA (creatinine), LDH (lactic dehydrogenase) and creatine kinase (CK) than the normal control group. Treatment with resveratrol reduced muscle damage as evidenced by the significantly decreased serum levels of UA, CREA, LDH and CK after contusion-induced muscle injuries in mice. In addition, RES and RES + NSAID groups promoted muscle satellite cell regeneration with increase in desmin protein after injury. Our results suggest that resveratrol combined with NSAID potentially improve muscle recovery and may be a potential candidate for further development as an effective clinical treatment for muscle repair.

The Synergistic Effects of Resveratrol combined with Resistant Training on Exercise Performance and Physiological Adaption.

The comprehensive studies done on resveratrol (RES) support that this polyphenol has multiple bioactivities and is widely accepted for dietary supplementation. Furthermore, regular exercise is known to have benefits on health and is considered as a form of preventive medicine. Although the vast majority of prior studies emphasize the efficacy of aerobic exercise in promoting physiological adaptions, other types of exercise, such as resistance exercise and high-intensity interval training (HIIT), may achieve similar or different physiological outcomes. Few studies have looked into the effectiveness of a combinational, synergistic approach to exercise using a weight-loading ladder climbing animal platform. In this study, ICR mice were allocated randomly to the RES and training groups using a two-way ANOVA (RES × Training) design. Exercise capacities, including grip strength, aerobic performance, and anaerobic performance, were assessed and the physiological adaptions were evaluated using fatigue-associated indexes that were implemented immediately after the exercise intervention. In addition, glycogen levels, muscular characteristics, and safety issues, including body composition, histopathology, and biochemistry, were further elucidated. Synergistic effects were observed on grip strength, anaerobic capacities, and exercise lactate, with significant interaction effects. Moreover, the training or RES may have contributed significantly to elevating aerobic capacity, tissue glycogen, and muscle hypertrophy. Toxic and other deleterious effects were also considered to evaluate the safety of the intervention. Resistance exercise in combination with resveratrol supplementation may be applied in the general population to achieve better physiological benefits, promote overall health, and promote participation in regular physical activities.

Effect of Lactobacillus Plantarum TWK10 on Improving Endurance Performance in Humans.

Microbiota is currently an important issue in disease and health and many studies have revealed it to play an important role in physiological homeostasis and health promotion. Lactobacillus plantarum (L. plantarum), isolated from Taiwan pickled vegetables, is a well-known probiotic microorganism. In a recent animal study, it was shown that supplementation of mice with L. plantarum TWK10 (TWK10) could increase muscle mass, improve exercise performance and exert anti-fatigue effects. In order to examine the ergogenic effect of TWK10 supplementation on endurance performance in humans, we conducted a human double-blind placebo-controlled clinical study. A total of sixteen adult subjects over 20 years of age were recruited and randomly allocated to the placebo or TWK10 group (n = 8 each). The TWK10 group received 6 weeks of supplementation. Physiological assessments were conducted by exhaustive treadmill exercise measurements and related biochemical indexes. After 6 weeks of supplementation, levels of lactic acid, blood ammonia, blood glucose, free fatty acid (FFA) and creatine kinase (CK) were evaluated during exhaustive exercise. We were able to show that the TWK10 group had significantly higher endurance performance and glucose content in a maximal treadmill running test compared to the placebo group (P < 0.05), suggesting that TWK10 supplementation may be beneficial to energy harvest. Taken together, our results suggest that TWK10 has the potential to be an aerobic exercise supplement for physiological adaptation or an ergogenic supplement with health benefits for amateur runners.

Low Second-To-Fourth Digit Ratio Has High Explosive Power? A Prepubertal Study.

Hsu, CC, Fong, TH, Chang, HM, Su, B, Chi, CP, Kan, NW, and Hsu, MC. Low second-to-fourth digit ratio has high explosive power? A prepubertal study. J Strength Cond Res 32(7): 2091-2095, 2018-A recent study reported that lower limb explosive power had no correlation with the index finger: ring finger (2D:4D) ratio. However, many studies hypothesized that a lower 2D:4D ratio (reflecting a relative higher testosterone exposure) predicts higher physical fitness. The aim of this study was to replicate the study of explosive power and the 2D:4D ratio in a sample of Taiwanese children. A total of 541 Taiwanese prepubertal children (257 girls and 284 boys aged 9-10 years) participated in this study. This study analyzed the relationship between the 2D:4D ratio and explosive power. Explosive power of the lower limbs was assessed using the standing long jump (SLJ) test. The lengths of the second and fourth fingers of the right hand were measured to calculate the 2D:4D ratio. The SLJ length was correlated with the 2D:4D ratios (r = -0.144, p = 0.015) in boys. After controlling for age and the body mass index, this correlation remained significant (r = -0.134, p = 0.024). For girls, 2D:4D ratios were not significantly correlated with SLJ scores. These results indicate that the SLJ distance was negatively correlated with the 2D:4D ratio in boys, but not in girls. These findings might suggest that prenatal testosterone exposure is negatively correlated with the explosive power in men, but not in women.

Whey Protein Improves Marathon-Induced Injury and Exercise Performance in Elite Track Runners.

Whey protein has been widely applied to athletes and the fitness field for muscle growth and performance improvement. Limited studies focused on the beneficial effects of whey on aerobic exercise according to biochemical assessments. In the current study, 12 elite male track runners were randomly assigned to whey and maltodextrin groups for 5 weeks' supplementation. The aim of this study was to investigate the effect of whey protein on physiological adaptions and exercise performance. During this period, three time points (pre-, post-, and end-test) were used to evaluate related biochemical parameters, body composition, and performance. The post-test was set 1 day after a marathon for injury status evaluation and the end-test was also assessed after 1-week recovery from endurance test. The results showed that the whey group exhibited significantly lower aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatine kinase indicators after the marathon (post-test), as well as at the end-test (p<0.016). The endurance performance in twelve-minute walk/run was also significantly elevated (p<0.012) possibly due to an increase in the muscle mass and amelioration of exercise injuries. In the current study, we demonstrated that whey protein can also be used for aerobic exercise for better physiological adaptation, in addition to resistance training. Whey protein could be also a potential nutrient supplement with a variety of benefits for amateur runners.

Benefits of different intensity of aerobic exercise in modulating body composition among obese young adults: a pilot randomized controlled trial.

BACKGROUND: The aim of present study was to compare the effects of different aerobic exercise intensities and energy expenditures on the body composition of sedentary obese college students in Taiwan. METHODS: Forty-eight obese participants [body mass index (BMI) ≥ 27 kg/m2, age 18-26 years] were randomized into four equal groups (n = 12): light-intensity training group (LITG), 40%-50% heart rate reserve (HRR); middle-intensity training group (MITG), 50%-70% HRR; high-intensity training group (HITG), 70%-80% HRR; and control group (CG). The aerobic exercise training program was conducted for 60 min per day on a treadmill 3 days per week for 12 weeks. All participant anthropometric data, blood biochemical parameters, and health-related physical fitness components were measured at baseline and after 12 weeks. RESULTS: At baseline, the anthropometric indices did not differ significantly among the four groups (p > 0.05). After 12-week exercise intervention, the HITG and MITG had significantly more changes in body weight, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) than the LITG. The changes in BMI and body fat percentage differed among all four groups (p < 0.05). CONCLUSIONS: A 12-week high-intensity exercise intervention with high energy expenditure can considerably reduce body weight, body fat, WC, WHR, and WHtR, whereas a light-intensity exercise intervention can significantly reduce body weight and body fat. TRIAL REGISTRATION: Current Controlled Trials TPECTR09831410900 , registered on 24th Dec 2009.

Ratings of Perceived Exertion and Physiological Parameters of Muscle Metabolism in Postmenopausal Women.

We compared responses from postmenopausal women living a sedentary lifestyle ( n = 15; Mean age= 59; SD = 4.2) to a single bout of water- or land-based exercise with respect to ratings of perceived exertion (RPE), lactate concentration, and muscle oxygen saturation. Each participant was randomly assigned to a single water- or land-based 50-minute bout of combined aerobic and resistance exercise. Blood samples were collected to detect pre- and post-exercise lactate concentration. Total hemoglobin, deoxidized hemoglobin, and the percentage change in the total oxygen saturation index (TSI%) of the rectus femoris were detected by means of near-infrared spectroscopy. We found similar RPE at various stages of land- and water-based exercise, and a similar change in lactate concentration in these environments (in water: 4.35 ± 1.49 mol/L; on land: 3.62 ± 1.18 mol/L). However, the reduction in HHb response was less pronounced after water-based exercise, and TSI% increased on land but decreased in water, with the magnitude of this change much higher on land. For similar RPE and lactate concentration, the oxygen saturation in the exercising muscles decreased in water, suggesting higher oxygen consumption in water than on land.

Neuromuscular Activity and Muscular Oxygenation Through Different Movement Cadences During In-water and On-land Knee Extension Exercise.

Chien, K-Y, Kan, N-W, Liao, Y-H, Lin, Y-L, Lin, C-L, and Chen, W-C. Neuromuscular activity and muscular oxygenation through different movement cadences during in-water and on-land knee extension exercise. J Strength Cond Res 31(3): 750-757, 2017-The purpose of this study was to determine the influence of various knee extension exercise cadences on neuromuscular activation and hemodynamic properties of the quadriceps muscle in water and on land. Seventeen young women participated in this study, and the subjects were randomly allocated to perform loaded knee extension exercises in water and on land at 4 different cadences of 30, 50, 70, and 90 b·min. Heart rate (HR), blood flow (BF), total saturation index (TSI) of oxygen, electromyography (EMG) for the extent of muscular activity, and rate of perceived exertion (RPE) were measured. Response values of HR, BF, TSI, and RPE at each cadence were obtained by subtracting the resting values from the indicator values measured at the respective cadences. We observed that BF, EMG, and RPE in water at 90 b·min were comparable with those on land. The HR and TSI changes were higher in water compared with on land (p = 0.004 and p = 0.013, respectively). In conclusion, we demonstrate that the neuromuscular activity when performing knee extension exercises at 90 b·min in water was comparable with that on land. However, exercising in water at the same cadence evoked higher TSI responses and greater cardiovascular challenges. A knee extension exercise at 90 b·min is the recommended operating speed of rehabilitation in water.

Effects of Resveratrol Supplementation and Exercise Training on Exercise Performance in Middle-Aged Mice.

Resveratrol (RES) has antioxidative, anti-inflammatory, anticancer, antidiabetic, antiasthmatic, antalgic, and anti-fatigue activities. Exercise training (ET) improves frailty resulting from aging. This study evaluated the effects of a combination of RES supplementation and ET on the exercise performance of aged mice. C57BL/6J mice (16 months old) were randomly divided into four groups: an older control group (OC group), supplementation with RES group (RES group), ET group (ET group), and a combination of ET and RES supplementation group (ET+RES group). Other 10-week-old mice were used as a young control group (Y-Ctrl group). In this study, exercise performance was evaluated using forelimb grip strength and exhaustive swimming time, as well as levels of plasma lactate, ammonia, glucose, and creatine kinase after an acute swimming exercise. Our results showed that the forelimb grip strength of mice in the ET+RES group was significantly higher than those in the OC, RES, and ET groups (by 1.3-, 1.2-, and 1.1-fold, respectively, p < 0.05), and exhibited no difference with the Y-Ctrl group. The endurance swimming test showed that swimming times of the ET and ET+RES groups were significantly longer than those of the OC and RES groups. Moreover, plasma lactate and ammonia levels of the ET + RES group after acute swimming exercise were significantly lower compared to the OC group (p < 0.05). Thus, it was suggested that by combining RES supplementation with ET for 4 weeks, the muscle strength and endurance performance of aged mice were significantly improved compared to the single intervention with either RES or ET alone. This combination might help shorten the extent of deterioration accompanying the aging process.

Effect of whole-body vibration training on body composition, exercise performance and biochemical responses in middle-aged mice.

AIMS: Whole-body vibration (WBV) is a well-known light-resistance exercise by automatic adaptations to rapid and repeated oscillations from a vibrating platform, which is also a simple and convenient exercise for older adults. However, the potential benefits of WBV on aging-associated changes in body composition, exercise performance, and fatigue are currently unclear. The objective of the study is to investigate the beneficial effects of WBV training on body composition, exercise performance, and physical fatigue-related and biochemical responses in middle-aged mice. METHODS: In total, 24 male C57BL/6 mice aged 15 months old were randomly divided into 3 groups (n=8 per group): sedentary control (SC), relatively low-frequency WBV (5.6 Hz, 2 mm, 0.13 g) (LV), and relatively high-frequency WBV (13 Hz, 2 mm, 0.68 g) (HV). Mice in the LV and HV groups were placed inside a vibration platform and vibrated at different frequencies and fixed amplitude (2 mm) for 15 min, 5 days/week for 4 weeks. Exercise performance, core temperature and anti-fatigue function were evaluated by forelimb grip strength and levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after a 15-min swimming exercise, as were changes in body composition and biochemical variables at the end of the experiment. RESULTS: Relative muscle and brown adipose tissue weight (%) was significantly higher for the HV than SC mice, but relative liver weight (%) was lower. On trend analysis, WBV increased grip strength, aerobic endurance and core temperature in mice. As well, serum lactate, ammonia and CK levels were dose-dependently decreased with vibration frequency after the swimming test. Fasting serum levels of albumin and total protein were increased and serum levels of alkaline phosphatase and creatinine decreased dose-dependently with vibration frequency. Moreover, WBV training improved the age-related abnormal morphology of skeletal muscle, liver and kidney tissues. Therefore, it could improve exercise performance and ameliorate fatigue and prevent senescence-associated biochemical and pathological alterations in middle-aged mice. CONCLUSIONS: WBV training may be an effective intervention for health promotion in the aging population. The detailed molecular mechanism of how WBV training regulates anti-aging activity warrants further functional studies.

Hypolipidemic effects and safety of Lactobacillus reuteri 263 in a hamster model of hyperlipidemia.

We aimed to verify the beneficial effects of probiotic strain Lactobacillus reuteri 263 (Lr263) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups: normal (n = 8), standard diet (control), and experimental (n = 32), a HCD. After a two-week induction followed by a six-week supplementation with Lr263, the 32 hyperlipidemic hamsters were divided into four groups (n = 8 per group) to receive vehicle or Lr263 by oral gavage at 2.1, 4.2, or 10.5 × 10(9) cells/kg/day for 6 weeks, designated the HCD, 1X, 2X and 5X groups, respectively. The efficacy and safety of Lr263 supplementation were evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG) cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. Lr263 supplementation dose dependently increased serum HDL-C level and decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. In addition, Lr263 supplementation had few subchronic toxic effects. Lr263 could be a potential agent with a hypolipidemic pharmacological effect.