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SUMMARY: Obesity is commonly associated with chronic tissue inflammation and skeletal muscle dysfunction. The study aimed to investigate the effects of High-Intensity Interval training (HIIT) on myokines and endoplasmic reticulum (ER) stress of diet- induced obese (DIO) mice. Three-month-old C57BL/6 male mice were fed a control (C) diet (n=20) or a high-fat (HF) diet (n=20) for 16 weeks. Then, half of the groups underwent HIIT (treadmill running) for an additional four weeks. HIIT increased calf muscles' contribution to BW (+24 %) and reduced weight gain in HF/HIIT than in HF (-120 %). Intramuscular fat accumulation was observed in HF and HF/ HIIT. Peak velocity was higher in HF/HIIT compared to HF (+26 %). Plasma insulin did not change, but glycemia was lower in HF/HIIT than in HF (-30 %). Fndc5 (+418 %) and Irisin (+72 %) were higher in HF/HIIT than in HF. Muscle Fgf21 was higher in HF/HIIT compared to HF (+30 %). In addition, NfKb (-53 %) and Tnfa (-63 %) were lower in HF/HIIT than in HF. However, Il1b (-86 %), Il6 (- 48 %), Il7 (-76 %), and Il15 (-21 %) were lower in HF/HIIT than in HF. Finally, HIIT reduced ER stress in HF/HIIT compared to HF: Atf4, -61 %; Chop, -61 %; Gadd45, -95 %. In conclusion, HIIT leads to weight loss and avoids muscle depletion. HIIT improves blood glucose, Irisin-Fndc5, and peak velocity. In addition, HIIT mitigates muscle inflammation and ER stress.
La obesidad es asociada comúnmente con inflamación tisular crónica y disfunción del músculo esquelético. El estudio tuvo como objetivo investigar los efectos del entrenamiento de intervalos de alta intensidad (HIIT) en las mioquinas y el estrés del retículo endoplásmico (ER) de ratones obesos inducidos por dieta (DIO). Se alimentó a ratones macho C57BL/6 de tres meses de edad con una dieta control (C) (n=20) o una dieta rica en grasas (HF) (n=20) durante 16 semanas. Luego, la mitad de los grupos se sometieron a HIIT (carrera en una trotadora) durante cuatro semanas más. HIIT aumentó la contribución de los músculos de la pantorrilla al BW (+24 %) y redujo el aumento de peso en HF/HIIT en HF (-120 %). Se observó acumulación de grasa intramuscular en HF y HF/HIIT. La velocidad máxima fue mayor en HF/HIIT en comparación con HF (+26 %). La insulina plasmática no cambió, pero la glucemia fue menor en HF/HIIT que en HF (-30 %). Fndc5 (+418 %) e Irisin (+72 %) fueron mayores en HF/HIIT que en HF. El Fgf21 muscular fue mayor en HF/ HIIT en comparación con HF (+30 %). Además, NfKb (-53 %) y Tnfa (-63 %) fueron menores en HF/HIIT que en HF. Sin embar- go, Il1b (-86 %), Il6 (-48 %), Il7 (-76 %) e Il15 (-21 %) fueron más bajos en HF/HIIT que en HF. Finalmente, HIIT redujo el estrés de RE en HF/HIIT en comparación con HF: Atf4, -61 %; Picar, - 61 %; Gadd45, -95 %. En conclusión, HIIT conduce a la pérdida de peso y evita el agotamiento muscular. HIIT mejora la glucosa en sangre, Irisin-Fndc5 y la velocidad máxima. Además, HIIT mitiga la inflamación muscular y el estrés ER.
Subject(s)
Animals , Male , Mice , Cytokines/physiology , Muscle, Skeletal/physiology , Endoplasmic Reticulum Stress/physiology , High-Intensity Interval Training , Obesity , Gene Expression , Inflammation , Mice, Inbred C57BL , Molecular BiologyABSTRACT
The consumption of alcoholic beverages influences carbohydrate and lipid metabolism, although it is not yet clear whether metabolism during physical exercise at different intensities is also affected. This was the objective of the present study. Eight young and healthy volunteers performed a treadmill test to identify the running speed corresponding to a lactate concentration of 4 mM (S4mM). At least 48 h later, they were subjected to two experimental trials (non-alcohol or alcohol) in which they performed two 1-km running sessions at the following intensities: 1) S4mM; 2) 15% above S4mM. In both trials, blood lactate, triglycerides, and glucose concentrations were measured before and after exercise. The acute alcohol intake increased triglycerides, but not lactate concentration under resting conditions. Interestingly, alcohol intake enhanced the exercise-induced increase in lactate concentration at the two intensities: S4mM (non-alcohol: 4.2±0.3 mM vs alcohol: 4.8±0.9 mM; P=0.003) and 15% above S4mM trial (P=0.004). When volunteers ingested alcohol, triglycerides concentration remained increased after treadmill running (e.g., at S4mM - at rest; non-alcohol: 0.2±0.5 mM vs alcohol: 1.3±1.3 mM; P=0.048). In contrast, glucose concentration was not modified by either alcohol intake, exercise, or their combination. We concluded that an acute alcohol intake changed lactate and lipid metabolism without affecting blood glucose concentration. In addition, the increase in lactate concentration caused by alcohol was specifically observed when individuals exercised, whereas augmented triglycerides concentration was already observed before exercise and was sustained thereafter.
Subject(s)
Humans , Male , Adult , Young Adult , Physical Endurance/drug effects , Blood Glucose/metabolism , Alcohol Drinking/blood , Lactic Acid/blood , Ethanol/metabolism , Alcoholic Beverages/analysis , Physical Endurance/physiology , Triglycerides/blood , Blood Glucose/analysis , Exercise Test , Athletic Performance/physiologyABSTRACT
Objective To observe the effect of wheel running and treadmill running on the cognitive functioning of rats after the extraction of a molar.Methods Thirty-two Sprague-Dawley rats were randomly divided into a control group (group C,n =8),a molar extraction group (ML group,n =8),a wheel running pretreatment group (W-ML group,n=8) and a treadmill running pretreatment group (T-ML group,n =8).The rats in the T-ML and W-ML groups practiced wheel running and treadmill running for 1 week,then they and the rats in the ML group received molar extraction surgery.One week later,a passive avoidance test was used to evaluate the cognitive functioning of all of the rats.Results No significant differences were found in the groups' average latency I times,but the average latency II time of the ML group was significantly shorter.There was no significant difference in the average latency II times of the T-ML and W-ML groups.Conclusion Either wheel running or treadmill running can promote learning and memory after molar loss by oral surgery,at least in rats.
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Objective To observe the alteration of capillary density and apelin/APJ expression in soleus muscles of high-fat diet rats.Methods Male 5-week-old Sprague-Dawley rats were randomly divided into a control group and a high-fat diet group.After 12 weeks of high-fat diet,16 rats were se lected and randomly divided into a sedentary group and a treadmill running group.The exercise rats underwent 60-minute treadmill running at 26 m/min 5 days a week for 10 weeks.The body weight,body fat and blood lipid level were measured for all rats.The protein expression of Soleus CD31 and apelin was determined using immunohistochemical staining,soleus apelin content was determined using the radioimmunoassay,and the mRNA expression of apelin/APJ was detected using real-time PCR.Results Compared with the control group,significant increase was observed in the body weight,body fat and the level of total triglyceride,total cholesterol and low density lipoprotein cholesterin,but significant decrease was found in the high density lipoprotein cholesterin in the high-fat diet group.There were no significant differences in the capillary density and mRNA levels of apelin/APJ between the two groups.Compared with the sedentary high-fat diet group,significant improvement was observed in the body weight and blood lipid level of the treadmill running group.Moreover,significant increase was also observed in the capillary density,the expression of apelin/APJ mRNA,as well as that of apelin protein in the treadmill running group (P＜0.05).Conclusion The treadmill running can significantly increase capillary density of obese rats,as it may activate the expression of Apelin/APJ.
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Objective To observe the effect of treadmill running on skeletal muscle lipid deposition,and the expression of vascular endothelial growth factor-B(VEGFB)and its receptor in soleus muscles of high-fat diet mice.Methods Thirty-two 5-week-old C57BL/6 male mice were randomly divided into a control group(n=8)and a high-fat diet group(n=24),and fed with normal and high-fat diet respectively.Eight weeks later,16 obesity mice were selected from the latter group and randomly divided into a sedentary group(n=8)and a treadmill running group(n=8).The running group underwent treadmill running at 25 m/min for an hour every day,five days a week for 8 weeks,while the other two groups did not do any exercises.The weight was measured before the mice were killed.The soleus lipid deposition level was determined using oil red O staining,The expression of VEGFR1 and Neuropilin-1(NRP1)was determined using the immunohistochemical staining,while the mRNA expression of VEGFB,VEG-FR1,NRP1 and peroxisome proliferator-activated receptor-γcoactivator-1α (PGC-1α) was detected using the real-time PCR.Results Compared with the control group,a significant increase was observed in the weight and the soleus lipid deposition of the high-fat diet group,while there were no significant differences in the expression of VEGFB,NRP1,VEGFR1 and PGC-1α.mRNA between the two groups.Compared with the sedentary obese mice,significant decrease in the body weight and soleus lipid deposition,significant increase in VEGFR1 mRNA expression,but no significant changes in the expression of VEGFB,NRP1 and PGC-1α mRNA were observed in the treadmill-running obese mice.Conclusion The treadmill running has no effect on the VEGFR1 expression in soleus of obese mice,but significantly up-regulates the expression of its receptors.It indicates that the treadmill running can lower the intramyocellular lipid deposition as it can strengthen the VEGFB/VEGFR1 in soleus muscles.
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Objective To investigate the effect of treadmill running with different intensities on type Ⅱ collagen (Col2) of knee joint articular cartilages in rats.Methods A total of 48 adult Sprague-Dawley rats were randomly divided into a control (C) group,a low-intensity exercise (L) group,a moderate-intensity exercise (M)group and a high-intensity exercise (H) group,each of 12.Rats in three exercises groups were regularly trained on treadmill at low,moderate,and high intensities respectively.Eight weeks later,all the animals were sacrificed.The right tibial plateau samples were collected to observe collagen fibers under polarizing light microscopy,and the collagen Ⅱ content were examined using immunohistochemistry.The mRNA expression of biglycan (BGN),fibromodulin (FMOD) and Col2 was tested using the quantitative real-time reverse transcription-polymerase chain reaction.Results Compared with group C,collagen fibers in group L and M exhibited almost the same organization,whereas,alteration in organization and shape of collagen fibers was found in group H.Significantly lower content of type Ⅱ collagen was found in group H than that in group C.In comparison with group C,group L had significantly higher gene expression of Col2,whereas group H had significantly higher BGN mRNA expression.Conclusion Low-or moderate-intensity treadmill running appears to have beneficial effect on articular cartilages to maintain its integrity.Highintensity exercises induce lower content and disorder of type Ⅱ collagen in articular cartilages,but the self-healing of cartilage may still exist.
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Objective To explore the effect of treadmill running at different intensities on three-dimensional structure of rat subchondral bones.Methods A total of 24 female Wistar rats were randomly assigned into a sedentary (SED) group,a low-intensity running (LIR) group,a medium-intensity running (MIR) group,or a high-intensity running (HIR) group,each of 6.Rats in LIR,MIR and HIR groups underwent treadmill running exercises with respective protocol,while rats in SED group serve as controls.Eight weeks later,all animals were sacrificed and their proximal end of tibia was examined using Micro-CT.Results Compared with SED group,in HIR group the subchondral plate became thicker with higher BMD and lower porosity,while trabecular bone became more and denser with higher BMD and a more plate-like architecture.LIR and MIR failed to result in considerable changes in the microstructure.Conclusion Treadmill running has an intensity-dependent effect on the three-dimensional structures of subchondral bones.High-intensity running can evoke significant structural changes in subchondral bones.
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Objective To investigate the effect of treadmill running pretreatment on the expression of CyclinA and CyclinE protein in hippocampus of rats after global cerebral ischemia and reperfusion.Meth-ods 60 healthy male wister rats were randomly divided into control group, model group and experiment group.Global cerebral ischemia reperfusion model was generated by improved four-vessel occlusion as de-scribed according to the description of Pulsinelli's method.Rats in the experiment group were performed treadmill running for 2 weeks before injury.The water maze test was performed at 24 h and 48 h respectively after injury to determine the spatial memory ability of rats.Morphological changes of hippocampus were ob-served by HE staining ( hematoxylin-eosin staining) at 3 h,6 h,24 h,48 h after injury and the expression of CyclinA and CyclinE were detected by immunohistochemical staining.Results Compared with control group,the survival rate of neurons in the model group was significantly decreased at each time point.Morris water maze test showed that the escaping latency of rats in the model group was significantly prolonged( 24 h (24.35±3.99)s,48 h(33.08±5.85)s),and the frequency of crossing the platform was decreased(24 h(6.80 ±0.79),48 h(4.00±0.67)).The expression of CyclinA was increased significantly in the model group ((8.40±0.52)/high view,(11.70±1.06)/high view,(15.50±0.53)/high view,(22.40±0.52)/high view) as well as the expression of CyclinE((20.30±0.48)/high view,(15.20±0.63)/high view,(10.00± 0.82)/high view,(7.70±0.68)/high view) (P<0.05).Compared with model group,the survival rate of neurons in the model group was significantly increased at each time point.Morris water maze test showed that the escaping latency of rats in the experiment group was significantly shorten(24 h(13.21±2.73) s,48 h (24.20±4.66)s),and the frequency of crossing the platform was increased(24 h(9.70±0.95),48 h(6.30± 1.16)).The expression of CyclinA was significantly increased in the model group((10.60±0.84)/high view),(16.70± 0.68)/high view),(24.50±0.53)/high view),(36.20±1.40)/high view) as well as the expression of CyclinE((31.60 ±0.70)/high view),(24.50±0.70)/high view),(16.80±0.63)/high view),(9.10±0.74)/high view) (P<0.05).Con-clusion The treadmill running pretreatment improves the function of spatial memory after global cerebral ischemia and reperfusion,potenlially mediated by regulating the expression for cell cycle proteins,which have a protective effect on cerebral brain tissue.
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There is evidence that brain temperature (Tbrain) provides a more sensitive index than other core body temperatures in determining physical performance. However, no study has addressed whether the association between performance and increases in Tbrain in a temperate environment is dependent upon exercise intensity, and this was the primary aim of the present study. Adult male Wistar rats were subjected to constant exercise at three different speeds (18, 21, and 24 m/min) until the onset of volitional fatigue. Tbrain was continuously measured by a thermistor inserted through a brain guide cannula. Exercise induced a speed-dependent increase in Tbrain, with the fastest speed associated with a higher rate of Tbrain increase. Rats subjected to constant exercise had similar Tbrain values at the time of fatigue, although a pronounced individual variability was observed (38.7-41.7°C). There were negative correlations between the rate of Tbrain increase and performance for all speeds that were studied. These results indicate that performance during constant exercise is negatively associated with the increase in Tbrain, particularly with its rate of increase. We then investigated how an incremental-speed protocol affected the association between the increase in Tbrain and performance. At volitional fatigue, Tbrain was lower during incremental exercise compared with the Tbrain resulting from constant exercise (39.3±0.3 vs 40.3±0.1°C; P<0.05), and no association between the rate of Tbrain increase and performance was observed. These findings suggest that the influence of Tbrain on performance under temperate conditions is dependent on exercise protocol.
Subject(s)
Animals , Male , Body Temperature/physiology , Brain/physiology , Environment, Controlled , Fatigue/physiopathology , Physical Conditioning, Animal/physiology , Physical Exertion/physiology , Body Temperature Regulation/physiology , Brain/anatomy & histology , Exercise Test , Physical Conditioning, Animal/methods , Rats, Wistar , Statistics as Topic , Volition/physiologyABSTRACT
Objective To observe the effect of transcutanous electrical acupoint stimulation(TEAS)on the exercise ability of rats.Methods After stereotaxis surgery,twenty male adult SD rats wera randomly divided into control group (n=10)and TEAS group(n=10).Two days after surgery.the rats were trained to adapt the treadmill mnning and TEAS(continuous wave,2Hz,5mA)was applied to right Zusanli (ST 36) for 30min,once a day for 6 days.Basic microdialysis samples of extracellular serotonin(5-HT)in rats'dorsal raphe nucleus(DRN)were collected 7 days after surgery.During experiment,rats were running on treadmill (10m/min for 10min,then gradually increased to 24m/min for 1 hour,0% grade).Microdialysis samples were collected continuously until 5 hours after treadmill running.The frequency of brush-stimulation during the running was recorded.Meanwhile,plasma amino acid content was examined 5 hours after exercise.Results The frequencies of brush-stimulation during the treadmill running in control group and TEAS group were 2.04+0.46 and 0.40+0.080 times per minute,respectively (P0.05).However,plasma free-TRP(f-TRP)content,f-TRP/T-TRP ratio and f-TRP/BCAA ratio decreased significantly(P<0.05) in TEAS group as compared with the control group.Extracellular 5-HT levels in DRN in control group soon after exercise were higher than their base levels(P<0.05),and decreased in sequential two hours,and then increased significantly 3 hours and 4 hours after exercise as compared with that 2 hours after exercise(P<0.05).There was a slow decline in the levels of extracellular 5-HT in TEAS group at each time-point after exercise,and significant lower than that in control group within 5 hours after exercise(P<0.05).Conclusion TEAS atZusanli(ST36)can effectively improve exercised ability by reducing peripheral free-TRP level and transporting TRP into the brain,and thus decreasing the synthesis of 5-HT in the brain.
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To investigate the effects of exercise on femoral regional bone mineral density and osteocyte micromorphology in young ovariectomized (OVX) rats, animals were divided into an ovariectomized group (OVX group), an ovariectomized + exercise group (OVX + exercise group), and a sham surgery group (SHAM group). Femoral bone mineral density was significantly lower in the OVX and OVX + exercise groups than in the SHAM group. A large difference in bone mineral density in the distal femoral epiphysis was observed between the OVX and OVX + exercise groups. In the OVX group, bone lacunae showed less immunostaining for DMP-1(dentin matrix protein-1) and osteocyte processes were fewer than in the SHAM group. In the OVX + exercise group, osteocyte processes were thicker (0.44 to 0.66 μm) than in the OVX group (0.22 to 0.26 μm). These results indicate that exercise induced structural changes in the femur, including formation of osteocyte processes and strengthening of the communication network between osteocytes.
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O objetivo deste estudo foi avaliar o efeito da alteração ambiental no nível de cortisol salivar e concentração de lactato sanguíneo de atletas de Handebol durante a corrida em esteira. Dezoito atletas participaram de quatro triagens experimentais de corrida em esteira com duração de 20 minutos a 70% de velocidade de pico. Os atletas foram orientados para correr: Na Linha de base, durante 20 min.; na segunda triagem experimental durante 10 minutos, sendo que no 10º minuto receberam a instrução para correr durante mais 10 minutos (fragmentada); na terceira triagem experimental durante 10 minutos e no 10º minuto foram informados que deveriam correr mais 20 minutos (superestimada); na quarta triagem experimental os atletas não receberam informação sobre a duração da corrida (indefinida). Durante as triagens experimentais foram avaliados: freqüência cardíaca, cortisol salivar e lactato sanguíneo. A ANOVA two-way foi usada para verificar diferençasestatisticamente significativas (p<0,05). Foram verificadas diferenças estatisticamente significativas para as triagens experimentais fragmentada e superestimada no nível de cortisol salivar (nmol/l) ao 11º minuto (11,59±1,92, *p=0,042) e (10,60±1,48, *p=0,046), e para a concentração de lactato sanguíneo (mM) no pós-teste (17,28±1,82) e (17,19±1,01), respectivamente. Os resultados sugerem que o efeito do ambiente é uma interferência importante na resposta metabólica durante o exercício físico.
The aim this study to evaluate the effect of environmental alteration in salivary cortisol levels and blood lactate concentration during treadmill running in handball athletes. Eighteen athletes participated in four treadmill running experimental trials with duration of 20 minutes at 70% of peak speed. The athletes were instructed to run: At baseline, for 20 min; at second experimental trial for 10 minutes, being that at the 10th minute they received the instruction to run for more 10 minutes (fragmented); at the third experimental trial for 10 minutes and at the 10th minute they were informed that they should run more 20 minutes (overestimated); at the fourth experimental trial the athletes did not receive information about the duration of the race (undefined). During the experimental trials were evaluated: affect, subjective perception of effort, heart frequency and cortisol levels. The two-way ANOVA were used to verify statistically significant differences (p<0,05). Differences statistically significant 4were verified at fragmented and overestimated trials the salivary cortisol level (nmol / l) for 11th (11.59±1.92, *p=0.042) and (10.60±1,48, *p=0046), and the blood lactate concentration (mM) in the post-test (17.28 ± 1.82) and (17.19 ± 1.01), respectively. The results suggest that the effect of the environment is an important interference in the metabolic response during exercise. Key-words: Treadmill running, Cortisol, Lactate.
Subject(s)
Humans , Male , Female , Athletes , Hydrocortisone , Lactic Acid , Metabolism , Running , Exercise , JoggingABSTRACT
This study investigated how different treadmill running periods effected bone mechanical strength in ovariectomized mice. Eighty female ICR mice aged 12-weeks-old were used. All mice were divided into 8 groups (<i>n</i>=10) randomly, and had either a sham-operation (<i>n</i>=10) or an ovariectomy (<i>n</i>=70). The SHAM group and one OVX group (NR) were used as non-running control groups, with the remainder comprising the treadmill running groups : the LA (8 m/min), MA (16 m/min), and HA (24 m/min) groups which ran for 12 weeks, and the LB (8 m/min), MB (16 m/min), HB (24 m/min) groups which ran for 6 weeks for 25 min on 5 days/week. After this experiment, maximum loads for the femur and tibia were measured by three-pointed bending test, and the bone mechanical strength of the bones was calculated. Also, the dry bone weight and ash content of the bones were measured. Maximum femur and tibia load and bone mechanical strength were affected by running speed and term significantly. Maximum load and bone mechanical strength of tibia were shown as an interaction. Bone mechanical strength in all running groups was higher than that in the NR group, significantly. This study suggested that treadmill running prevented a reduction of bone mechanical strength, and that treadmill running was most effective in the LA and MA groups (running at low and medium speed and for a long period).
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The purpose of this study was to investigate the effects of regular treadmill running on GLUT4 protein of skeletal muscle in STZ-diabetic rats. I used 19 male Sprague-Dawley rats weighing 140 to 160 grams. Rats were randomly assigned into normal, diabetes(DM) and DE(DE) groups. The exercise was loaded with treadmill running for 5 days per week during 4 weeks. All experimental procedures were carried out following overnight fasting 48 hours after last exercise. Gain(gm) in body weight in DM rats(82+/-2.4) was lowered compared to normal rats(109+/-2.8), and decreased by exercise. Plasma glucose concentration(mg/dl) in DM rats was 143+/-3.1 which is higher than that of normal group of 103+/-6.4. The concentration of DE group was lower than that of DM rats. Plasma insulin concentration(micronU/ml) of DM and DE rats was significantly lowerd compared to normal rats. There was no difference of plasma concentrations of FFA and HDL cholesterol among noraml, DM and DE groups. Plasma triglyceride concentration(mg/dl) was significantly highered in DM group compared to those of DM group, the concentration of DE group was lower. Glycogen concentration(mg/gm wet weight) of the plantaris muscle in DM and DE groups was significantly reduced compared to normal group. Glucose transporter 4(GLUT4) protein of soleus was analyzed by Western blot. In DM group, the GLUT4 protein level was markdly decreased compared to normal group, but the level was recovered to the level of normal group by 4 weeks treadmill running. In conclusion, the insulin resistance induced by STZ administration was partially improved by 4 weeks physical training in rats.
Subject(s)
Animals , Humans , Male , Rats , Blood Glucose , Blotting, Western , Body Weight , Cholesterol, HDL , Fasting , Glucose Transport Proteins, Facilitative , Glucose Transporter Type 4 , Glycogen , Insulin , Insulin Resistance , Muscle, Skeletal , Plasma , Rats, Sprague-Dawley , Running , TriglyceridesABSTRACT
The influence of daily physical exercise on oxygen utilizing capacity of working muscle investigated by means of measureing lactate threshold (LT) during progressive treadmill running from the comparison between soccer group (S group: N=12, 11.9±0.1 years of age) and control group (C group ; N=14, 11.8±0.1 years of age) . LT<SUB>1</SUB> was determined as the point where blood lactate concentration (La) increased from rest level, and LT<SUB>2</SUB> was determined by the gradient, La/VO<SUB>2</SUB>. body weight<SUP>-1</SUP> (2 mM/10 ml. kg<SUP>-1</SUP>, min<SUP>-1</SUP>) .<BR>LT<SUB>1</SUB> and LT<SUB>2</SUB> in S group were significantly higher than those in C group expressed with absolute and relative values of VO<SUB>2</SUB> (1. min<SUP>-1</SUP>, ml. kg<SUP>-1</SUP>. min<SUP>-1</SUP>, % VO<SUB>2</SUB>max) . No significant differences in La, ventilation responses, and heart rate at the point of LT<SUB>1</SUB> and LT<SUB>2</SUB> were observed between S and C group, La showed slight decrease and was kept at lower level in S group with increase of VO<SUB>2</SUB>, compared with C group. On the contrary, La in C group began to increase at lower level of VO<SUB>2</SUB>. From our previous longitudinal study of LT in non-athletic children, we observed that LT shifted to lower level with growth. It was sugesed that La curve of S group, such shift had not occurred. Differences of these patterns in VO<SUB>2</SUB> and La between athletic children and non-athletic children were similar to those observed in adults athletes and non-athletes.<BR>In conclusion it was supposed that sufficient daily physical training in 10-12 year of age might increase oxygen utilizing capacity of leg working muscle during running exercise.