Autophagic Signaling and Proteolytic Enzyme Activity in Cardiac and Skeletal Muscle of Spontaneously Hypertensive Rats following Chronic Aerobic Exercise

Hypertension is a cardiovascular disease associated with deleterious effects in skeletal and cardiac muscle. Autophagy is a degradative process essential to muscle health. Acute exercise can alter autophagic signaling. Therefore, we aimed to characterize the effects of chronic endurance exercise on autophagy in skeletal and cardiac muscle of normotensive and hypertensive rats. Male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were assigned to a sedentary condition or 6 weeks of treadmill running. White gastrocnemius (WG) of hypertensive rats had higher (p<0.05) caspase-3 and proteasome activity, as well as elevated calpain activity. In addition, skeletal muscle of hypertensive animals had elevated (p<0.05) ATG7 and LC3I protein, LAMP2 mRNA, and cathepsin activity, indicative of enhanced autophagic signaling. Interestingly, chronic exercise training increased (p<0.05) Beclin-1, LC3, and p62 mRNA as well as proteasome activity, but reduced (p<0.05) Beclin-1 and ATG7 protein, as well as decreased (p<0.05) caspase-3, calpain, and cathepsin activity. Left ventricle (LV) of hypertensive rats had reduced (p<0.05) AMPKα and LC3II protein, as well as elevated (p<0.05) p-AKT, p-p70S6K, LC3I and p62 protein, which collectively suggest reduced autophagic signaling. Exercise training had little effect on autophagy-related signaling factors in LV; however, exercise training increased (p<0.05) proteasome activity but reduced (p<0.05) caspase-3 and calpain activity. Our results suggest that autophagic signaling is altered in skeletal and cardiac muscle of hypertensive animals. Regular aerobic exercise can effectively alter the proteolytic environment in both cardiac and skeletal muscle, as well as influence several autophagy-related factors in skeletal muscle of normotensive and hypertensive rats.     

Serum levels of appetite-regulating hormones and pro-inflammatory cytokines are ameliorated by a CLA diet and endurance exercise in rats fed a high-fat diet

[Purpose]

This study examined whether conjugated linoleic acid (CLA) supplementation and endurance exercise affect appetite-regulating hormones and pro-inflammatory cytokines in rats.

[Methods]

Seven-week-old male Sprague-Dawley rats were divided randomly into the high-fat diet sedentary group (HS, n=8), the 1.0% CLA supplemented high-fat diet sedentary group (CS, n=8), and the 1.0% CLA supplemented high-fat diet exercise group (CE, n=8). Rats in the CE group swam 60 min/day, 5 days/week for 4 weeks.

[Results]

Leptin and insulin levels in the CS and CE groups were significantly lower than those in the HS group (p<0.001), whereas leptin (p<0.01) and insulin (p<0.05) levels decreased significantly in the CE compared to those in the CS group. Interleukin (IL)-1β (p<0.001) and IL-6 (p<0.01) levels in the CS and CE groups decreased significantly compared to those in the HS group. Leptin (IL-1β: r=0.835, p<0.001), IL-6 (r=0.607, p<0.05), insulin (IL-1β: r=0.797, p<0.01), and IL-6 (r=0.827, p<0.01) levels were positively related with pro-inflammatory cytokine levels.

[Conclusion]

Endurance exercise may play an important role during CLA supplementation of rats on a high-fat diet.     

Saffron (Crocus Sativus L.), Combined with Endurance Exercise,Synergistically Enhances BDNF,Serotonin, and NT-3 in Wistar Rats

Background:Evidence indicates that combined approaches based on exercise and nutrition benefit neural development. We aimed to determine the effect of saffron and endurance training on hippocampus neurogenic factors, neurotrophin-3 gene expression in soleus muscle, and short-term memory in Wistar rats.Methods:The study analyzed four groups of ten rats each: control, exercise, saffron, and saffron plus exercise. The rats in the exercise groups were trained on a rodent motor-driven treadmill. All rats were gavage daily with either saffron extract (40 mg/kg) or water. After eight weeks of intervention all rats were evaluated using the novel object recognition (NOR) test. Blood and tissue samples were collected to measure proteins and neurotrophin-3 gene expression.Results:Rats that received saffron treatment combined with exercise had significantly greater brain-derived neurotrophic factor (BDNF) and serotonin in hippocampus compared to the control and saffron-only-treated rats (p< 0.05). Neurotrophin-3 mRNA in soleus muscle was higher in the saffron plus exercise group than rats in the other three groups (p< 0.05). Hippocampus 5-hydroxyindolacetic acid and short-term memory were significantly greater in all the intervention groups than in the control group (p< 0.05).Conclusion:Saffron, combined with endurance exercise, synergistically increased hippocampus BDNF, serotonin, and muscular neurotrophin-3 mRNA in Wistar rats.Key Words: Endurance Exercise, Memory, Hippocampus, Saffron, Neurotransmitter     

The effects of a single bout pilates exercise on mRNA expression of bone metabolic cytokines in osteopenia women

[Purpose]

The purpose of this study was to examine the effect of a single bout pilates exercise on mRNA expression of bone metabolic cytokines in elderly osteopenia women.

[Methods]

We selected 11 people of elderly osteopenia women and loaded a single bout pilates exercise about RPE 10-14 level. The blood samples were collected before, immediately after and 60 minute after pilates exercise, then examined calcium metabolic markers in serum and extracted peripheral blood mononuclear cell (PBMC) from whole blood and confirmed mRNA expression of bone metabolic cytokines from PBMC. To clarify the changes during exercise, we designed repeated measure ANOVA as the control group to perform blood sampling without exercise.

[Results]

As a result, serum P showed significant interaction effect between group and time (p<.001), the pilates exercise group decreased about 9% at immediately after exercise and 13% during recovery after exercise (p<.05), while the control group showed a tendency to increase. Serum CK also showed a significant interaction between group and time (p<.05), the pilates group significantly increased at immediately after exercise and during recovery after exercise (p<.05) but the control group didn’t have changes. TNF-α and IL-6 mRNA expression in PBMC was significantly increased in the pilates group (p<.01, p<.05), although INF-γ mRNA expression didn’t show statistically significant difference, it tended to increase in the pilates group (NS).

[Conclusion]

These results suggested that a single bout pilates exercise of elderly osteopenia women cause hypophosphatemia with temporary muscle damage, and it leading high turnover bone metabolic state with to activate both of bone formation and bone resorption.     

The effect of exercise training and water extract from propolis intake on the antioxidant enzymes activity of skeletal muscle and liver in rat

[Purpose]

In this study, the authors have intended to investigate the effects that the exercise training and the intake of the water extract from propolis have on the activity of antioxidant enzymes.

[Methods]

For this purpose, the exercise training (70% VO₂max treadmill running exercise for 60min)of 5 times per week for six weeks and the intake (50mg/kg/day) of the water extract from propolis were performed by separating the experimental animals (SD rats, n=32) into CON(n=8) group, CON+Ex(n=8), PA(n=8), and PA+Ex(n=8).

[Results]

As a result, the following conclusions were obtained: The concentration of the blood glucose and insulin of the CON+Ex group and PA+Ex group which are the exercise parallel group were significantly decreased in comparison with the control group, whereas if comparing the glycogen concentration in skeletal muscle and liver tissue between the exercise parallel group and the CON group, the former showed significantly high value in comparison with the latter (p < .05). In the case of the activity of the antioxidant enzyme in the skeletal muscle and the liver tissue, the activities of SOD, GPX and CAT in the gastrocnemius muscle tissue of the experimental animals showed significantly high value in PA+Ex group in comparison with other experimental groups (p < .05). In addition, the SOD activity in the liver tissue showed that only PA+Ex group was significantly increased, whereas GDX activity showed significantly higher value in CON+Ex group and PA group than CON group (p < .05). However, the activity of CAT in the liver tissue showed that there is no difference between the experimental groups. As a result that measured the concentration of MDA in order to evaluate the damage level of the tissue by oxygen free radicals, the difference between the groups in the liver tissue was not shown, while it was shown that only PA+Ex group in the skeletal muscle tissue was significantly decreased in comparison with other experimental groups (p < .05).

[Conclusion]

Taken together the above findings, it is considered that the parallel treatment of the exercise training and the water extract from propolis can not only increase the use of glycogen of the skeletal muscle and liver tissue, but also it can give the effect to suppress the creation of active oxygen by inducing the activity of the antioxidant enzyme in the body, and in the future, the possibility as the exercise supplements and the antioxidant of the water-soluble propolis are expected.     

The effect of exercise on expression of myokine and angiogenesis mRNA in skeletal muscle of high fat diet induced obese rat

[Purpose]

The purpose of this study was to investigate the effect of regular treadmill exercise on the mRNA expressions of myokines and angiogenesis factors in the skeletal muscle of obese rats.

[Methods]

Thirty two male Sprague-Dawley rats (4weeks old) were divided into the CO (control) and HF (high fat diet) groups. Obesity was induced in the HF group by consumption of 45% high-fat diet for 15 weeks. These groups were further subdivided into training groups (COT and HFT); the training groups conducted moderate intensity treadmill training for 8 weeks. Soleus muscles were excised and analyzed by real-time quantitative PCR.

[Results]

mRNA expression of myokines, such as PGC-1α, IL-6, and IL-15, in the COT and HFT groups (which conducted regular exercise), were higher as compared with the CO and HF groups (p < 0.05). Also, the levels in the HF group were significantly lower when compared with CO group (p < 0.05). Expression of angiogenesis mRNA, namely mTOR, VEGF, and FLT1, were significantly lower in the HF group, as compared to the CO group (p < 0.05). In addition, COT group had a higher expression of mTORC1, mTORC2, VEGF and FLT mRNA, than the CO group (p < 0.05); the HFT group also had higher expressions of mTOR, VEGF and FLT1 mRNA than the HF group (p < 0.05).

[Conclusion]

These results indicate that mRNA expression of myokines was increased through the activity of muscle contraction, and it also promoted the mRNA expression of angiogenesis due to activation of mTOR. Thus, we conclude that not only under normal health conditions, but in obesity and excess nutritional circumstances also, regular exercise seems to act positively on the glycemic control and insulin sensitivity through the angiogenesis signaling pathway.     

Effect of BCAA intake during endurance exercises on fatigue substances,muscle damage substances,and energy metabolism substances

The increase rate of utilization of branched-chain amino acids (BCAA) by muscle is reduced to its plasma concentration during prolonged exercise leading to glycogen. BCAA supplementation would reduce the serum activities of intramuscular enzymes associated with muscle damage. To examine the effects of BCAA administration on fatigue substances (serotonin, ammonia and lactate), muscle damage substances (CK and LDH) and energy metabolism substances (FFA and glucose) after endurance exercise. Subjects (n = 26, college-aged males) were randomly divided into an experimental (n = 13, EXP) and a placebo (n = 13, CON) group. Subjects both EXP and CON performed a bout of cycle training (70% VO₂max intensity) to exhaustion. Subject in the EXP were administrated BCAA (78ml/kg·w) prior to the bout of cycle exercise. Fatigue substances, muscle damage substances and energy metabolism substances were measured before ingesting BCAAs and placebos, 10 min before exercise, 30 min into exercise, immediately after exercise, and 30 min after exercise. Data were analyzed by two-way repeated measure ANCOVA, correlation and statistical significance was set at p < 0.05. The following results were obtained from this study; 1. In the change of fatigue substances : Serotonin in the EXP tended to decreased at the 10 min before exercise, 30 min into exercise, post exercise, and recovery 30 min. Serotonin in the CON was significantly greater than the EXP at the10 min before exercise and recovery 30. Ammonia in the EXP was increased at the 10 min before exercise, 30 min into exercise, and post exercise, but significantly decreased at the recovery 30min (p < 0.05). Ammonia in the CON was significantly lower than the EXP at the 10 min before exercise, 30 min into exercise, and post exercise (p < 0.05). Lactate in the EXP was significantly increased at the 30 min into exercise and significantly decreased at the post exercise and recovery 30 min. Lactate in the CON was significantly lower than the EXP at the post exercise (p < 0.05). 2. In the change of muscle damage substances : CK in the EXP was decreased at the 10 min before exercise and increased at the 30 min into exercise and then decreased at the post exercise and recovery 30 min. CK in the CON was greater than the EXP. LDH in the EXP was decreased at the 10 min before exercise and increased at the 30 min into exercise and then decreased at the post exercise and recovery 30 min. LDH in the CON was higher than the EXP. 3. In the change of energy metabolism substances :Glucose in the EXP tended to decrease at the 10 min before exercise, 30 min into exercise, post exercise and recovery 30 min. Glucose in the CON was significantly greater than the EXP at the recovery 30 min (p < .05). FFA in both EXP and CON was increased at the post exercise and recovery 30 min. % increase for FFA in the EXP was greater than the CON at the post exercise and recovery 30 min. 4. The relationship of the fatigue substances, muscle damage substances and energy metabolism substances after endurance exercise indicated strongly a positive relationship between LDH and ammonia and a negative relationship between LDH and FFA in the EXP. Also, there were a strong negative relationship between glucose and FFA and a positive relationship between glucose and serotonin in the EXP. There was a strong positive relationship between CK and LDH and a strong negative relationship between FFA and glucose in the CON. These results indicate that supplementary BCAA decreased serum concentrations of the intramuscular enzymes as CK and LDH following exhaustive exercise. This observation suggests that BCAA supplementation may reduce the muscle damage associated with endurance exercise.     

The acute muscular response following a novel form of pulsed direct current stimulation (Neubie) or traditional resistance exercise

Objectives:To examine changes in muscle thickness (MT), soreness (SOR), and isometric torque (ISO) following exercise with pulsed direct current (Neubie) or traditional high-load (TRAD) exercise.Methods:Thirty-two participants had SOR, MT, and ISO measured before, immediately after, and 24 and 48h following TRAD and Neubie. Rating of perceived exertion (RPE) and discomfort were also measured. Results are displayed as means(SD).Results:For MT, there was a condition x time interaction (p<0.001). For Neubie, MT increased pre [3.7(0.7)cm] to post [3.9(0.8) cm, p<0.001] and remained elevated at 24h. For TRAD, MT increased pre [3.7(0.6)cm] to post [4.0 (0.7)cm, p<0.001] and remained up to 48h. Greater values were observed for TRAD post-exercise. For ISO, both conditions decreased up to 48h. TRAD demonstrated a greater change post exercise (p<0.001). For SOR, both conditions increased up to 48h. Neubie demonstrated greater SOR at 48h (p=0.007). RPE was higher for all sets in TRAD [Mean across sets=16.0(1.9) vs. 13.5(2), p<0.001]. Discomfort was higher in all sets for Neubie [Mean across sets=5.8(1.5)vs. 4.5(2.0), p<0.05].Conclusions:Both conditions showed increased SOR, and decreased ISO for up to 48h, with MT increased for up to 24h. MT remained elevated in TRAD at 48h. Neubie training might be effective for individuals who are looking to experience lower RPE responses during exercise.     

Effects of branched-chain amino acid supplement on knee peak torque and indicators of muscle damage following isokinetic exercise-induced delayed onset muscle soreness

[Purpose] This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplement on delayed onset muscle soreness (DOMS) by analyzing the maximum muscle strength and indicators of muscle damage.[Methods] Twelve men with majors in physical education were assigned to the BCAA group and placebo group in a double-blinded design, and repeated measurements were conducted. DOMS was induced with an isokinetic exercise. Following BCAA administration, the changes in the knee extension peak torque, flexion peak torque, aspartate aminotransferase (AST), creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were analyzed. The maximum knee muscle strength was measured at the baseline (pre-D0) following BCAA administration for 5 days before exercise (-D5, -4D, -3D, -2D, -1D). In contrast, the post-treatment measurements (D3) were recorded after BCAA administration for 3 days (post-D0, D1, D2). Blood samples were obtained before (pre-D0), immediately after (post-D0), 24 h (D1), 48 h (D2), and 72 h (D3) after the exercise to analyze the indicators of muscle strength. BCAA was administered twice daily for 8 days (5 days and 3 days before inducing DOMS and during the experimental period, respectively).[Results] There was no difference in the flexion peak torque between the groups. However, the BCAA group showed a significantly higher extension peak torque at D3 (second isokinetic exercise), compared to the placebo group (p<.05). There was no difference in AST changes between the groups. Nonetheless, the CK and LDH were significantly reduced in the BCAA group, compared to the placebo group. There was no correlation between the extension peak torque and flexion peak torque. However, the CK and LDH increased proportionately in DOMS. Moreover, their concentrations significantly increased with a decreasing peak torque (p<.01).[Conclusion] An exercise-induced DOMS results in a decrease in the peak torque and a proportional increase in the CK and LDH concentrations. Moreover, the administration of BCAA inhibits the reduction of the extension peak torque and elevation of CK and LDH concentrations. Therefore, BCAA might be administered as a supplement to maintain the muscle strength and prevent muscle damage during vigorous exercises that may induce DOMS in sports settings.     

Differential effects of low-magnitude high-frequency vibration on reloading hind-limb soleus and gastrocnemius medialis muscles in 28-day tail-suspended rats

Objectives:Low-magnitude high-frequency vibration (LMHFV) was reported beneficial to muscle contractile functions in clinical and preclinical studies. This study aims to investigate the effects of LMHFV on myofibers, myogenic cells and functional properties of disused soleus (Sol) and gastrocnemius medialis (GM) during reloading.Methods:Sprague Dawley rats were hind-limb unloaded for 28 days and assigned to reloading control (Ctrl) or LMHFV group (Vib). Sol and GM of both groups were harvested for fiber typing, proliferating myogenic cell counting and in vitro functional assessment.Results:Myogenic cells proliferation was promoted by LMHFV in both Sol and GM (p<0.001 and p<0.05 respectively). Force generating capacity was not much affected (Vib=Ctrl, p>0.05) but fast-fiber favorable changes in fiber type switching (more type IIA but lower type I in Vib; p<0.05 and 0.01 respectively) and fiber hypertrophy (type I, Vib<Ctrl; p<0.01) were observed mainly in GM.Conclusion:LMHFV was not detrimental to reloading muscles but the outcomes were muscle dependent. The unique fiber type composition and anatomical differences between Sol and GM might render the differential muscle responses to LMHFV. Further investigations on myofibers type specific responses to different LMHFV regimes and myogenic cell interaction with associated myofiber were proposed.     

Effects of combined hip exercise and passive stretching on muscle stiffness,pain perception and painrelated disability,and physical function in older adults with low back pain

[Purpose] This study aimed to examine the effects of combined hip exercise and passive stretching as a novel treatment method for low back pain (LBP) in older adults.[Methods] Altogether, 20 Koreans with LBP aged 60–79 years (67.3 ± 5.92 years) were randomly assigned to undertake combined exercise (CE; n = 10) or lumbar stabilization exercise (LSE; n = 10). All participants performed their respective exercise program for 25–30 min with an OMNI scale of 6–8 for 8 weeks, three times a week. Body composition, muscle stiffness, pain-visual analog scale (P-VAS), Oswestry disability index, and physical function were evaluated before and after the exercise intervention.[Results] The CE group demonstrated greater improvements in lean body mass (η² = 0.402, p = 0.003) and percent body fat (η² = 0.222, p = 0.036) than the LSE group. Both groups demonstrated significant improvements in muscle stiffness, P-VAS scores, and Oswestry disability index scores, although no significant differences were observed between the interventions. All physical function parameters demonstrated a significant improvement in both groups, and the CE group demonstrated greater improvement in the YMCA sit-and-reach (η² = 0.338, p = 0.007) and straight leg raise tests (η² = 0.283, p = 0.016) than the LSE group.[Conclusion] CE is comparable to LSE as an effective and successful exercise intervention that reduces muscle stiffness and P-VAS scores. Moreover, CE is more effective than LSE in enhancing the physical function of older adults with LBP.     

Human Muscle Protein Synthetic Responses during Weight-Bearing and Non-Weight-Bearing Exercise: A Comparative Study of Exercise Modes and Recovery Nutrition

Effects of conventional endurance (CE) exercise and essential amino acid (EAA) supplementation on protein turnover are well described. Protein turnover responses to weighted endurance exercise (i.e., load carriage, LC) and EAA may differ from CE, because the mechanical forces and contractile properties of LC and CE likely differ. This study examined muscle protein synthesis (MPS) and whole-body protein turnover in response to LC and CE, with and without EAA supplementation, using stable isotope amino acid tracer infusions. Forty adults (mean ± SD, 22 ± 4 y, 80 ± 10 kg, VO_2peak 4.0 ± 0.5 L∙min^-1) were randomly assigned to perform 90 min, absolute intensity-matched (2.2 ± 0.1 VO₂ L∙m^-1) LC (performed on a treadmill wearing a vest equal to 30% of individual body mass, mean ± SD load carried 24 ± 3 kg) or CE (cycle ergometry performed at the same absolute VO₂ as LC) exercise, during which EAA (10 g EAA, 3.6 g leucine) or control (CON, non-nutritive) drinks were consumed. Mixed-muscle and myofibrillar MPS were higher during exercise for LC than CE (mode main effect, P < 0.05), independent of dietary treatment. EAA enhanced mixed-muscle and sarcoplasmic MPS during exercise, regardless of mode (drink main effect, P < 0.05). Mixed-muscle and sarcoplasmic MPS were higher in recovery for LC than CE (mode main effect, P < 0.05). No other differences or interactions (mode x drink) were observed. However, EAA attenuated whole-body protein breakdown, increased amino acid oxidation, and enhanced net protein balance in recovery compared to CON, regardless of exercise mode (P < 0.05). These data show that, although whole-body protein turnover responses to absolute VO₂-matched LC and CE are the same, LC elicited a greater muscle protein synthetic response than CE.     

Effect of energy drink dose on exercise capacity,heart rate recovery and heart rate variability after high-intensity exercise

[Purpose]

The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink.

[Methods]

The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO₂max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO₂max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO₂max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min.

[Results]

Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05).

[Conclusion]

In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg^-1 ingestion of energy drink might be positive effect to increase exercise performance capacity without side-effect in cardiovascular disease.     

Effects of endurance exercise training on muscle glycogen accumulation in humans.

The purpose of this investigation was to determine whether endurance exercise training increases the ability of human skeletal muscle to accumulate glycogen after exercise. Subjects (4 women and 2 men, 31 +/- 8 yr old) performed high-intensity stationary cycling 3 days/wk and continuous running 3 days/wk for 10 wk. Muscle glycogen concentration was measured after a glycogen-depleting exercise bout before and after endurance training. Muscle glycogen accumulation rate from 15 min to 6 h after exercise was twofold higher (P < 0.05) in the trained than in the untrained state: 10.5 +/- 0.2 and 4.5 +/- 1.3 mmol. kg wet wt(-1). h(-1), respectively. Muscle glycogen concentration was higher (P < 0.05) in the trained than in the untrained state at 15 min, 6 h, and 48 h after exercise. Muscle GLUT-4 content after exercise was twofold higher (P < 0.05) in the trained than in the untrained state (10.7 +/- 1.2 and 4.7 +/- 0.7 optical density units, respectively) and was correlated with muscle glycogen concentration 6 h after exercise (r = 0.64, P < 0.05). Total glycogen synthase activity and the percentage of glycogen synthase I were not significantly different before and after training at 15 min, 6 h, and 48 h after exercise. We conclude that endurance exercise training enhances the capacity of human skeletal muscle to accumulate glycogen after glycogen-depleting exercise.     

Plyometric training effects on physical fitness and muscle damage in high school baseball players

[Purpose]The objective of this study was to investigate the effects of plyometric training on physical fitness and muscle damage in high school baseball players.[Methods]The participants in the study included 21 high school baseball players who are healthy and well-training. The participants were randomly allocated to the plyometric training (n=11) and control (n=10) groups. The plyometric training was applied 3 times a week for a total of 8 weeks and the control group took part in only regular baseball skills training without plyometric training. For physical fitness, measures included maximal strength (left and right hand-grip strength), muscle endurance (sit-up), agility (side-step), power (standing long jump), and balance (left and right Rhomberg test). For muscle damage, creatine kinase (CK) and lactate dehydrogenase (LDH) levels were measured.[Results]The results showed a significant interaction effect between time and groups in left hand-grip strength (P = 0.022), side-step (P = 0.004), and standing long jump (P < 0.001) after the 8-week plyometric training, with greater improvement in the plyometric training group than the control group. On the other hand, there was no significant interaction effect between time and groups in right hand-grip strength, situp, left and right Rhomberg test, CK level, and LDH level (P > 0.05).[Conclusion]In conclusion, 8-week plyometric training had a positive effect on improving physical fitness, such as maximal strength, agility, and power, in high school baseball players without causing additional muscle damage.     

CHANGE IN BLOOD GELSOLIN CONCENTRATION IN RESPONSE TO PHYSICAL EXERCISE

Plasma gelsolin (pGSN) produced by muscle is an abundant protein of extracellular fluids capable of severing actin filaments and eliminating actin from the circulation. Additionally, pGSN modulates the cellular effects of some bioactive lipids. In this study we test the hypothesis that hormonal and metabolic adaptations to exercise are associated with changes in gelsolin concentration in blood. Plasma samples were collected from twenty healthy males recruited from untrained (UT, n=10) and endurance trained (ET, n=10) groups that performed 30-60 minutes of exercise on a cycloergometer at a workload corresponding to 70% of VO₂max. Gelsolin concentration was determined by quantitative Western blot analysis with an anti-human gelsolin antibody. The gelsolin concentration in UT and ET subjects before starting exercise ranged from 104 to 330 and 163 to 337 µg · ml^-1 respectively. After 30 minutes of exercise we observed a significant decrease of plasma gelsolin in the UT group (p<0.05) while the gelsolin concentration in the ET group rose on average from 244 to 271 µg · ml^-1. However, this increase did not reach statistical significance. Endurance training might increase the ability of muscle tissue to express plasma gelsolin as part of an adaptive mechanism.     

Endurance training reduces the contraction-induced interleukin-6 mRNA expression in human skeletal muscle

Contracting skeletal muscle expresses large amounts of IL-6. Because 1) IL-6 mRNA expression in contracting skeletal muscle is enhanced by low muscle glycogen content, and 2) IL-6 increases lipolysis and oxidation of fatty acids, we hypothesized that regular exercise training, associated with increased levels of resting muscle glycogen and enhanced capacity to oxidize fatty acids, would lead to a less-pronounced increase of skeletal muscle IL-6 mRNA in response to acute exercise. Thus, before and after 10 wk of knee extensor endurance training, skeletal muscle IL-6 mRNA expression was determined in young healthy men (n = 7) in response to 3 h of dynamic knee extensor exercise, using the same relative workload. Maximal power output, time to exhaustion during submaximal exercise, resting muscle glycogen content, and citrate synthase and 3-hydroxyacyl-CoA dehydrogenase enzyme activity were all significantly enhanced by training. IL-6 mRNA expression in resting skeletal muscle did not change in response to training. However, although absolute workload during acute exercise was 44% higher (P < 0.05) after the training period, skeletal muscle IL-6 mRNA content increased 76-fold (P < 0.05) in response to exercise before the training period, but only 8-fold (P < 0.05, relative to rest and pretraining) in response to exercise after training. Furthermore, the exercise-induced increase of plasma IL-6 (P < 0.05, pre- and posttraining) was not higher after training despite higher absolute work intensity. In conclusion, the magnitude of the exercise-induced IL-6 mRNA expression in contracting human skeletal muscle was markedly reduced by 10 wk of training.     

Improved Inflammatory Balance of Human Skeletal Muscle during Exercise after Supplementations of the Ginseng-Based Steroid Rg1

The purpose of the study was to determine the effect of ginseng-based steroid Rg1 on TNF-alpha and IL-10 gene expression in human skeletal muscle against exercise challenge, as well as on its ergogenic outcomes. Randomized double-blind placebo-controlled crossover trials were performed, separated by a 4-week washout. Healthy young men were randomized into two groups and received capsule containing either 5 mg of Rg1 or Placebo one night and one hour before exercise. Muscle biopsies were conducted at baseline, immediately and 3 h after a standardized 60-min cycle ergometer exercise. While treatment differences in glycogen depletion rate of biopsied quadriceps muscle during exercise did not reach statistical significance, Rg1 supplementations enhanced post-exercise glycogen replenishment and increased citrate synthase activity in the skeletal muscle 3 h after exercise, concurrent with improved meal tolerance during recovery (P<0.05). Rg1 suppressed the exercise-induced increases in thiobarbituric acids reactive substance (TBARS) and reversed the increased TNF-alpha and decreased IL-10 mRNA of quadriceps muscle against the exercise challenge. PGC-1 alpha and GLUT4 mRNAs of exercised muscle were not affected by Rg1. Maximal aerobic capacity (VO_2max) was not changed by Rg1. However, cycling time to exhaustion at 80% VO_2max increased significantly by ~20% (P<0.05). Conclusion: Our result suggests that Rg1 is an ergogenic component of ginseng, which can minimize unwanted lipid peroxidation of exercised human skeletal muscle, and attenuate pro-inflammatory shift under exercise challenge.     

Antioxidant and antiapoptotic effects of pine needle powder ingestion and endurance training in high cholesterol-fed rats

[Purpose]

Pine needle is a kind of medicinal plant ingested traditionally for a variety of purposes. Therefore, we examined the antioxidant and antiapoptotic capacities of pine needle ingestion in high cholesterol-fed and endurance exercise-trained rats.

[Methods]

Animals were divided into six groups as; CON: normal diet control group; EX: normal diet and exercise training group; HC: high cholesterol diet group; HCE: high cholesterol diet and exercise training group; HCP: high cholesterol and pine needle group; HCPE: high-cholesterol and pine needle diet with exercise training group, respectively. Each group consisted of seven Sprague-Dawley male rats. The swim-training groups, EX, HCE, and HCPE swam in the swim pool 60 min/d and 5 d/week for 5 weeks. During the rearing periods, freeze-dried pine needle powder mix with 5% of the high cholesterol diet was supplied to the HCP and HCPE groups. Gastrocnemius muscle was used as the skeletal muscle. Malondialdehyde (MDA), Mn-containing superoxide dismutase (Mn-SOD), Cu, Zn containing superoxide dismutase (Cu,Zn-SOD), and glutathione peroxidase (GPx) were analyzed for their antioxidant capacities. Finally, p53, Bcl-2 (B-cell lymphoma 2), caspase-3 protein expression was analyzed to determine antiapoptotic ability.

[Results]

MDA showed low content in HCPE compared to the HC. Mn-SOD, Cu,Zn-SOD, and GPx protein expression was significantly increased by pine needle ingestion and/or exercise training. In addition, suppression of p53 protein expression resulted in Bcl-2 increase followed by caspase-3 decrease with/without pine needle ingestion and exercise training.

[Conclusion]

When exercise training in addition to pine needle powder ingestion may be a helpful nutritional regimen to athletes and exercisers.