共查询到20条相似文献，搜索用时 31 毫秒
1.
The length-tension relationship of muscle contraction is well documented in adults. However, research on this relationship in children has been limited. The aim of this study was to compare differences in the torque-joint angle relationship of the quadriceps muscle in children and adults. Eight boys aged 8-10 years and eight men aged 20-26 years performed two maximal voluntary isometric contractions at six knee joint angles (20 degrees, 40 degrees, 60 degrees, 80 degrees, 90 degrees, 100 degrees). The mean of the two trials was used as the performance measure. Both groups demonstrated an expected increase in relative torque as the joint angle increased (P< 0.05). The men produced significantly greater relative torque at 20 degrees, 40 degrees and 60 degrees knee flexion (P < 0.05). The percentage of maximal torque at these angles for the men and boys respectively were: 35.2+/-4.3 vs 15.2+/-12%, 63.6+/-9.1 vs 51.8+/-16.8% and 93.6+/-6.5 vs 84.4+/-14.4%. There were no group differences at 80 degrees or 90 degrees. Peak torque was attained at 80 degrees in men, but decreased significantly (P< 0.05) at 90 degrees and 100 degrees. For boys, peak torque was attained at joint angles of 80 degrees and 90 degrees. The reduction in peak torque at 100 degrees was not statistically significant, but the relative torque at this angle was lower in men than in boys (77.9+/-13.7 vs 87.1+/-10.4%; P< 0.05). In conclusion, the relationship between torque and joint angle appears to be affected by age. 相似文献
2.
Portus MR Rosemond CD Rath DA 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):215-230
This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean +/- SD; age = 27.8 +/- 3.9 years) while performing in test, tour and one day international matches. Thirty-one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3 degrees, max = 22 degrees, mean +/- SD = 9 +/- 5 degrees), which by strict definition in the 2000 laws of cricket made them illegal. Five deliveries from three bowlers exhibited hyperextension of the bowling elbow (19 +/- 5 degrees). When assessed against an arbitrary threshold of 15 degrees for elbow straightening, ball speeds for deliveries above this threshold (39.5 +/- 2.0 m/s) were significantly faster (effect size = 1.4; p = 0.006) than deliveries below it (37.1 +/- 1.4 m/s). When grouped by delivery length, the bouncers and short deliveries recorded more elbow straightening (12 +/- 6.6 degrees) than the good length deliveries (9 +/- 4.4 degrees) and the full deliveries (8 +/- 5.7 degrees), although these were not statistically significant differences. The results of this study support the implementation of a tolerance threshold for assessing the legality of fast bowling actions. Further research is recommended into in-match kinematic modelling, laboratory based assessments of illegal bowling actions, perceptual aspects of bowling actions and remedial methods to reduce elbow straightening in bowling actions. 相似文献
3.
Orienteering is a sport in which it is common for most participants to be aged over 40 years, but research into the demands of the sport has focused almost exclusively on elite participants aged 21-35 years. The aim of the present study was to examine the heart rate responses of older male orienteers. Thirty-nine competitive male orienteers were divided into three groups: group 1 (international competitive standard, n = 11, age 21-67 years), group 2 (national competitive standard, n = 15, age 24-66 years) and group 3 (club competitive standard, n = 13, age 23-60 years). Each participant had his heart rate monitored during two orienteering races of contrasting technical difficulty. The results were analysed using analysis of covariance, with age as a covariate, and Pearson product-moment correlation coefficients to determine whether age was related to the observed heart rate responses. The groups did not differ in their peak (175 +/- 12 beats x min(-1), P = 0.643) or mean (159 +/- 13 beats x min(-1), P = 0.171) heart rates during the races. There was a decline of 6 beats x min(-1) x decade(-1) (P = 0.001) for peak heart rate and 5 beats x min(-1) x decade(-1) (P < 0.001) for mean heart rate. Mean heart rates were 86 +/- 6% of the participants' maximal heart rates and were not associated with age. The orienteers in group 1 displayed a lower (P < 0.005) within-race standard deviation in heart rate (6 +/- 2 beats x min(-1)) than those in groups 2 and 3 (10 +/- 3 and 10 +/- 4 beats x min(-1), respectively). In conclusion, the mean heart rates indicated that all three groups of orienteers ran at a relative high intensity and the international competitive standard orienteers displayed a less variable heart rate, which may have been related to fewer instances of slowing down to relocate and being able to navigate while running at relatively high speeds. 相似文献
4.
The thermoregulatory responses of upper-body trained athletes were examined at rest, during prolonged arm crank exercise and recovery in cool (21.5 +/- 0.9 degrees C, 43.9 +/- 10.1% relative humidity; mean +/- s) and warm (31.5 +/- 0.6 degrees C, 48.9 +/- 8.4% relative humidity) conditions. Aural temperature increased from rest by 0.7 +/- 0.7 degrees C (P< 0.05) during exercise in cool conditions and by 1.6 +/- 0.7 degrees C during exercise in warm conditions (P< 0.05). During exercise in cool conditions, calf skin temperature decreased (1.5 +/- 1.3 degrees C), whereas an increase was observed during exercise in warm conditions (3.0 +/- 1.7 degrees C). Lower-body skin temperatures tended to increase by greater amounts than upper-body skin temperatures during exercise in warm conditions. No differences were observed in blood lactate, heart rate or respiratory exchange ratio responses between conditions. Perceived exertion at 45 min of exercise was greater than that reported at 5 min of exercise during the cool trial (P< 0.05), whereas during exercise in the warm trial the rating of perceived exertion increased from initial values by 30 min (P < 0.05). Heat storage, body mass losses and fluid consumption were greater during exercise in warm conditions (7.06 +/- 2.25 J x g(-1) x degrees C(-1), 1.3 +/- 0.5 kg and 1,038 +/- 356 ml, respectively) than in cool conditions (1.35 +/- 0.23 J x g(-1) x degrees C(-1), 0.8 +/- 0.2 kg and 530 +/- 284 ml, respectively; P < 0.05). The results of this study indicate that the increasing thermal strain with constant thermal stress in warm conditions is due to heat storage within the lower body. These results may aid in understanding thermoregulatory control mechanisms of populations with a thermoregulatory dysfunction, such as those with spinal cord injuries. 相似文献
5.
Montgomery PG Pyne DB Hopkins WG Dorman JC Cook K Minahan CL 《Journal of sports sciences》2008,26(11):1135-1145
To evaluate the effectiveness of recovery strategies on physical performance during a 3-day tournament style basketball competition, 29 male players (mean age 19.1 years, s= 2.1; height 1.84 m, s= 0.34; body mass 88.5 kg, s= 14.7) were assigned to one of three treatment groups: carbohydrate+stretching (7.7 g kg(-1) day(-1), s= 1.7; 'n = 9), cold water immersion (11 degrees C, 5 x 1; n = 10) or full leg compression garments (18 mmHg, approximately 18 h; n = 10). Effects of the recovery strategies on pre-post tournament performance tests were expressed as the mean change (% +/- standard deviation of the change score). Changes and differences were standardized for accumulated game time, assessed against the smallest worthwhile change for each test, and reported qualitatively. Accumulated fatigue was evident over the tournament with small to moderate impairments in performance tests. Sprint and agility performance decreased by 0.7% (s = 1.3) and 2.0% (s = 1.9) respectively. Vertical jump decreased substantially after the first day for all treatments, and remained suppressed post-tournament. Cold water immersion was substantially better in maintaining 20-m acceleration with only a 0.5% (s = 1.4) reduction in 20-m time after 3 days compared with a 3.2% (s = 1.6) reduction for compression. Cold water immersion (-1.4%, s = 1.7) and compression (-1.5%, s = 1.7) showed similar substantial benefits in maintaining line-drill performance over the tournament, whereas carbohydrate+stretching elicited a 0.4% (s =1.8) reduction. Sit-and-reach flexibility decreased for all groups, although cold water immersion resulted in the smallest reduction in flexibility. Basketball tournament play elicited small to moderate impairments in physical test performance. In conclusion, cold water immersion appears to promote better restoration of physical performance measures than carbohydrate + stretching routines and compression garments. 相似文献
6.
In this article, we examined the antidepressant influence of an 8-week-long aerobic exercise intervention in which two training parameters were manipulated: exercise frequency and group environment. Twenty-three individuals with elevated symptoms of depression were recruited in a sport and fitness facility and agreed to participate in this 8-week study. They were randomly assigned to three groups: (a) low-frequency exercise (control) (n = 7), (b) high-frequency exercise (n = 8), and (c) high-frequency exercise + group-based intervention (n = 8). Participants completed the Beck Depression Inventory (BDI-II) at study entry, and at 4 and 8 weeks subsequently. The results showed that those in the high-frequency aerobic exercise experimental groups reported lower depression scores than those in the low-frequency (control) group at 4 weeks (13.2 +/- 7.3 and 11.7 +/- 3.1 vs. 22.4 +/- 7.5) and 8 weeks (10.9 +/- 8.1 and 9.6 +/- 2.5 vs. 20.7 +/- 6.3). However, alleviation in depressive symptoms was not found to be greater in those participants who received a group-based intervention. 相似文献
7.
Alegre LM Jiménez F Gonzalo-Orden JM Martín-Acero R Aguado X 《Journal of sports sciences》2006,24(5):501-508
The aims of this study were to assess changes in muscle architecture, isometric and dynamic strength of the leg extensor muscles, resulting from dynamic resistance training, and the relationships between strength and muscle architecture variables. The participants (n = 30) were randomly assigned to one of two groups. The training group (n = 16; age 21.8 +/- 2.3 years, body mass 74.8 +/- 9.2 kg, height 1.75 +/- 0.08 m) performed dynamic resistance training for 13 weeks. The control group (n = 14; age 19.9 +/- 1.5 years, body mass 74.0 +/- 8.5 kg, height 1.76 +/- 0.05 m) did not perform any resistance training. Maximal dynamic and isometric strength were tested in both groups, before and after the training period. The members of the training group used the free-weight squat lift (90 degrees ) as their training exercise. The concentric phase of the squat was performed explosively. Skeletal muscle architecture of the vastus lateralis was visualized using ultrasonography. At the end of the study, significant increases in vastus lateralis muscle thickness (+6.9%, P < 0.001), fascicle length (+10.3%, P < 0.05), one-repetition maximum (+8.2%, P < 0.05), rate of force development (+23.8%, P < 0.05) and average force produced in the first 500 ms (+11.7%, P < 0.05) were seen only in the training group. Adaptations to the muscle architecture in the training group limited the loss of fibre force, and improved the capacity for developing higher velocities of contraction. The architectural changes in the training group were similar to those seen in studies where high-speed training was performed. In conclusion, dynamic resistance training with light loads leads to increases in muscle thickness and fascicle length, which might be related to a more efficient transmission of fibre force to the tendon. 相似文献
8.
减量训练对大鼠骨骼肌最大等长收缩力的影响 总被引：1，自引：0，他引：1
为探讨减量训练对骨骼肌最大等长收缩力的影响.将成年S.D雄性大鼠随机分为2组,正常对照组（NC,16只）和快速力量训练组（PT,Power training,36只）.快速力量训练6周后,PT组又分为训练对照组（PTC,12只）、减量训练1组（PTT1,12只）和减量训练2组（PTT2,12只）.PTC组继续进行原训练,PTT1组和PTT2组进行6周减量训练.最后测定大鼠右侧后腿腓肠肌最大等长收缩力相对值（F/m）,观察减量训练对其的影响.结果表明,80%强度的减量训练后最大等长收缩力相对值呈先下降后回升直至超量恢复的趋势;50%强度的减量训练后相对值呈持续下降趋势,没有再回升.适当的减量训练可以巩固和加强训练效果;减量过多则会导致训练效果丧失,出现减量后的不良影响. 相似文献
9.
We estimated age at menarche in a cross-sectional sample of 159 competitive figure skaters aged 11-22 years. The sample represented three standards (test stream, pre-elite, elite) and three disciplines (free skaters, pair skaters, dancers). The status quo (yes/no) and retrospective methods were used. Estimated age at menarche based on probit analysis of the status quo data was 14.2 +/- 0.5 years, with 95% confidence intervals of 13.2 to 15.2 years. Mean recalled age at menarche for 67 skaters aged 16 years or over was 13.6 +/- 1.2 years. Comparisons of skaters by standard and discipline were limited to skaters > or = 16 years. Menarche was, on average, significantly later (P < 0.01) in elite (n = 36; 14.0 +/- 1.4 years) than in test stream (n = 15; 12.9 +/- 0.8 years) skaters. Age at menarche in pre-elite skaters (n = 16; 13.5 +/- 0.9 years) did not differ significantly from the other two groups. By discipline, menarche was, on average, significantly later (P < 0.01) in pair skaters (n = 12; 14.5 +/- 1.3 years) than in both free skaters (n = 38; 13.4 +/- 1.0 years) and dancers (n = 17; 13.4 +/- 1.4 years). Early maturing girls (menarche < 12.0 years; n = 2) were not represented in this sample of competitive figure skaters. Mean recalled age at menarche of mothers of skaters (n = 84) was 13.7 +/- 1.3 years and the mother-daughter correlation (n = 56 pairs) was 0.45 (P < 0.01). Later maturation was thus characteristic of competitive figure skaters, particularly in elite and more specialized pair skaters, and there was a significant familial resemblance. 相似文献
10.
In this study, we examined the effects of upper-body pre-cooling before intermittent sprinting exercise in a moderate environment. Seven male and three female trained cyclists (age 26.8+/-5.5 years, body mass 68.5+/-9.5 kg, height 1.76+/-0.13 m, V O2peak 59.0+/-11.4 mL. kg(-1). min(-1); mean+/-s) performed 30 min of cycling at 50% V O2peak interspersed with a 10-s Wingate cycling sprint test at 5 min intervals. The exercise was performed in a room controlled at 22 degrees C and 40% relative humidity. In the control session, the participants rested for 30 min before exercise. In the pre-cooling session, the participants wore the upper segment of a liquid conditioning garment circulating 5 degrees C coolant until rectal temperature decreased by 0.5 degrees C. Rectal temperature at the start of exercise was significantly lower in the pre-cooling (36.5+/-0.3 degrees C) than in the control condition (37.0+/-0.5 degrees C), but this difference was reduced to a non-significant 0.4 degrees C throughout exercise. Mean skin temperature was significantly lower in the pre-cooling (30.7+/-2.3 degrees C) than in the control condition (32.5+/-1.6 degrees C) throughout exercise. Heart rate during submaximal exercise was similar between the two conditions, although peak heart rate after the Wingate sprints was significantly lower in the pre-cooling condition. With pre-cooling, mean peak power (909+/-161 W) and mean overall power output (797+/-154 W) were similar to those in the control condition (peak 921+/-163 W, mean 806+/-156 W), with no differences in the subjective ratings of perceived exertion. These results suggest that upper-body pre-cooling does not provide any benefit to intermittent sprinting exercise in a moderate environment. 相似文献
11.
The effects of training with overweight and underweight cricket balls on fast-bowling speed and accuracy were investigated in senior club cricket bowlers randomly assigned to either a traditional (n = 9) or modified-implement training (n = 7) group. Both groups performed bowling training three times a week for 10 weeks. The traditional training group bowled only regulation cricket balls (156 g), whereas the modified-implement training group bowled a combination of overweight (161-181 g), underweight (151-131 g) and regulation cricket balls. A radar gun measured the speed of 18 consecutive deliveries for each bowler before, during and after the training period. Video recordings of the deliveries were also analysed to determine bowling accuracy in terms of first-bounce distance from the stumps. Bowling speed, which was initially 108 +/- 5 km h(-1) (mean +/- standard deviation), increased in the modified-implement training group by 4.0 km x h(-1) and in the traditional training group by 1.3 km x h(-1) (difference, 2.7 km x h(-1); 90% confidence limits, 1.2 to 4.2 km x h(-1)). For a minimum worthwhile change of 5 km x h(-1), the chances that the true effect on bowling speed was practically beneficial/trivial/harmful were 1.0/99/< 0.1%. For bowling accuracy, the chances were 1/48/51%. This modified-implement training programme is not a useful training strategy for club cricketers. 相似文献
12.
To determine gender differences, positional differences, and patterns of change in the performance of the basketball line-drill test, 93 male (mean age 16.8 years, s = 1.1) and 95 female (mean age 16.5 years, s = 1.0) basketball players undertook 516 line-drill tests over a 5-year period. Log-transformed performance times were analysed using a mixed model that included quadratic within-participant fixed effects for time in the season and time in the programme. Changes and differences were standardized for interpretation of magnitudes. Mean performance times were 28.0 s (s = 1.3) for males and 30.4 s (s = 1.3) for females. The mean pattern of change in performance within a season differed substantially between the sexes and playing positions: male guards and female centres showed moderate to very large improvements mid-season of 1.1% and 3.5% respectively (90% confidence limits +/-2.1% and +/-3.0%), while female guards and male forwards showed large to very large decrements of -1.6% (+/-2.6%) and -2.4% (+/-2.0%). Over 3 years, males improved performance across all three playing positions by 1.4% (+/-1.3%) and females by 2.9% (+/-1.4%). Males improved performance by 0.2% (+/-0.5%) per year, whereas the performance of females deteriorated by 0.6% (+/-0.4%) per year. The differing patterns of performance change presumably reflect variations in training and competition loads, with short-term fluctuations in performance being managed to promote longer-term improvements. 相似文献
13.
The aim of this study was to determine whether 3 weeks of intermittent normobaric hypoxic exposure at rest was able to elicit changes that would benefit multi-sport athletes. Twenty-two multi-sport athletes of mixed ability were exposed to either a normobaric hypoxic gas (intermittent hypoxic training group) or a placebo gas containing normal room air (placebo group). The participants breathed the gas mixtures in 5-min intervals interspersed with 5-min recovery periods of normal room air for a total of 90 min per day, 5 days per week, over a 3-week period. The oxygen in the hypoxic gas decreased from 13% in week 1 to 10% by week 3. The training and placebo groups underwent a total of four performance tests, including a familiarization and baseline trial before the intervention, followed by trials at 2 and 17 days after the intervention. Time to complete the 3-km run decreased by 1.7%[95% confidence interval (CI) = -0.6 - 3.9%] 2 days after, and by 2.3% (CI = 0.25 - 4.4%) 17 days after, the last hypoxic episode in the training relative to the placebo group. Substantial changes in the training relative to the placebo group also included increased reticulocyte count 2 days (23.5%; CI =-1.9 to 44.9%) and 12 days (14.6%; CI = -7.1 to 36.4%) post-exposure. The effect of intermittent hypoxic training on 3-km performance found in this study is likely to be beneficial, which suggests non-elite multi-sport athletes should expect such training to enhance performance. 相似文献
14.
The purpose of the present study was to re-examine the relationship between deep body temperature and relative exercise intensity, during running rather than cycling (Saltin and Hermansen, 1966). Twenty male competitive and recreational distance runners, aged 22 + 0.9 years (mean +/- sx), were selected to form two groups, one with high maximal oxygen uptake (VO2max) values (72.8 +/- 0.8 ml x kg(-1) x min(-1)) and the other with moderate values (59.4 +/- 0.7 ml x kg(-1) x min(-1)). The participants completed two 60 min constant-paced treadmill runs at a common speed (absolute intensity) of 10.5 km x h(-1) and at a relative exercise intensity at a speed equivalent to 65% of VO2max. During the relative exercise intensity trial, no differences were found in rectal temperature, skin temperature or heart rate between groups. However, when running at the common speed, differences were identified in rectal temperature. At 60 min, rectal temperature was 37.70 +/- 0.19 degrees C and 38.19 +/- 0.11 degrees C for the high and moderate VO2max groups, respectively (P < 0.05). Sweat lost was significantly higher in the moderate VO2max group (moderate: 1.05 +/- 0.06 kg x h(-1); high: 0.82 +/- 0.08 kg x h(-1); P < 0.05). Heart rates were also different between groups over the first 20 min during the common speed trial (P < 0.05). The results of the present study support the findings of Saltin and Hermansen (1966), in that the set-point at which temperature is maintained is related to the relative exercise intensity. 相似文献
15.
Delayed-onset muscle soreness refers to the skeletal muscle pain that is experienced following eccentric exercise. The aim of the present study was to examine the physiological effects of physical activity with or without ibuprofen on delayed onset muscle soreness. Forty-four non-athletic male volunteers (age 24.3 +/- 2.4 years) were randomly assigned to one of four groups: physical activity (n = 11), ibuprofen (n = 11), physical activity and ibuprofen (combination, n = 11), or control (n = 11). The physical activity programme comprised 5 min of walking and jogging, 10 min of static stretching of the hands and shoulder girdle, and 5 min of concentric movements with sub-maximal contractions. The total amount of ibuprofen consumed by a single individual was 2800 mg; this was taken from 1 h before the eccentric actions up to 48 h after it. Delayed onset muscle soreness was induced by performing 70 eccentric contractions of the biceps muscle of the non-dominant side on a modified arm curl machine. Perceived muscle soreness, maximal eccentric contraction, creatine kinase enzyme activity and elbow range of motion were assessed 1 h before and 1, 24 and 48 h after the eccentric actions. The results indicated that, after the eccentric actions, soreness increased (P < 0.001) across time in all groups, with the highest values being recorded at 24 h. At 24 and 48 h, greater soreness (P < 0.001) was observed in the control group than in the physical activity and combination groups. After the eccentric actions, creatine kinase increased and was elevated (P < 0.001) compared with baseline in all groups, with values returning to baseline in the physical activity and combination groups by 48 h. However, creatine kinase in the control and ibuprofen groups was still significantly higher than at baseline after 48 h. Creatine kinase was higher (P < 0.001) in the control group than in physical activity and combination groups at 24 and 48 h. There was also a reduction (P < 0.001) in elbow range of motion across time. This reduction in elbow range of motion was greater (P < 0.001) in the control and ibuprofen groups than in the physical activity and combination groups at 1, 24 and 48 h. The reduction in maximum eccentric contraction was greater (P < 0.001) in the control and ibuprofen groups than in the physical activity group at 24 and 48 h and the combination group at 48 h. In conclusion, the results add to our understanding of the effects of physical activity and the combination of physical activity and ibuprofen in reducing the severity of muscle soreness induced by eccentric exercise. Physical activity conducted before eccentric exercise alleviates muscle soreness. Our results indicate that physical activity with or without ibuprofen helps to prevent delayed-onset muscle soreness. 相似文献
16.
Maximal-intensity isometric and dynamic exercise performance after eccentric muscle actions 总被引：3，自引：2，他引：1
A well-documented observation after eccentric exercise is a reduction in maximal voluntary force. However, little is known about the ability to maintain maximal isometric force or generate and maintain dynamic peak power. These aspects of muscle function were studied in seven participants (5 males, 2 females). Knee extensor isometric strength and rate of fatigue were assessed by a sustained 60 s maximal voluntary contraction at 80 degrees and 40 degrees knee flexion, corresponding to an optimal and a shortened muscle length, respectively. Dynamic peak power and rate of fatigue were assessed during a 30 s Wingate cycle test. Plasma creatine kinase was measured from a fingertip blood sample. These variables were measured before, 1 h after and 1, 2, 3 and 7 days after 100 repetitions of the eccentric phase of the barbell squat exercise (10 sets x 10 reps at 80% concentric one-repetition maximum). Eccentric exercise resulted in elevations in creatine kinase activity above baseline (274+/-109 U x l(-1); mean +/- s(x)) after 1 h (506+/-116 U x l(-1), P < 0.05) and 1 day (808+/-117 U x l(-1), P < 0.05). Isometric strength was reduced (P < 0.05) for 7 days (35% at 1 h, 5% at day 7) and the rate of fatigue was lower (P < 0.05) for 3 days at 80 degrees and for 1 day at 40 degrees. Wingate peak power was reduced to a lesser extent (P < 0.05) than isometric strength at 1 h (13%) and, although the time course of recovery was equal, the two variables differed in their pattern of recovery. Eccentrically exercised muscle was characterized by an inability to generate high force and power, but an improved ability to maintain force and power. Such functional outcomes are consistent with the proposition that type II fibres are selectively recruited or damaged during eccentric exercise. 相似文献
17.
Kwak YS 《Journal of sports sciences》2006,24(9):973-978
The purpose of this study was to analyse the effect of regular exercise on spleen and peritoneal exudate reactive oxygen species (ROS) and lymphocyte proliferation by splenocytes. Twenty-four female BALB/c mice were randomly divided into trained (n = 12) and untrained (n = 12) groups. These two groups were further divided into mice that were studied at rest (trained/rest, n = 5; untrained/rest, n = 6) and immediately after a 2 h acute bout of exercise (trained/exercise, n = 6; untrained/exercise, n = 6). The animals were bred in the animal facility of the Yonsei University College of Medicine, where they were housed in a temperature- (22 - 24 degrees Celsius) and humidity- (50 - 60%) controlled environment, with a 12 h photoperiod, and provided with food and water ad libitum. The trained mice underwent 10 weeks of endurance swimming training (5 days per week) in water at 26 - 29 degrees Celsius for 60 min. Changes in body mass, proliferative activity and the production of reactive oxygen species from spleen lymphocytes and peritoneal exudate cells were determined. The splenic lymphocytes of the trained mice had much greater proliferative activity than those of the untrained mice (P < 0.05). Trained mice had lower ROS production in splenic lymphocytes and peritoneal exudate cells than untrained mice. In both groups, there was substantial inhibition of proliferative activity stimulated with medium, concanavalin A and lipopolysaccharide following the acute bout of exercise. This may have been caused by excessive ROS production following the acute exercise session. 相似文献
18.
目的:观察"脑舒合剂"对大鼠过度运动后大脑单胺类神经递质的影响.为中药制剂消除运动性中枢疲劳提供实验依据.方法:将雄性SD大鼠40只(体重230±20克),随机分为:空白对照组(C组)、负重游泳组(O组)、负重游泳加低剂量组(低药组n=10,生药10g/kg)和负重游泳加高剂量组(高药组n=10,生药30g/kg).每天C组和0组灌等量蒸馏水,低药组和高药组灌服"脑舒合剂".除C组外,其余三个组递增负荷游泳至第八周.结果:经过8周大负荷游泳后,O组大鼠大脑皮质的去甲肾上腺素(NE)阳性表达水平显著性降低,低药组和高药组无显著性变化;O组大鼠大脑皮质的五羟色胺(5一HT)阳性表达水平显著性升高,低药组和高药组无显著性变化.结论:"脑舒合剂"有助于维持大脑皮质的NE水平,抑制5-HT水平升高,使大脑皮质的兴奋与抑制过程处于相对平衡状态,对过度运动后的大脑功能有良性作用. 相似文献
19.
Effects of concurrent training on interleukin-6, tumour necrosis factor-alpha and C-reactive protein in middle-aged men 总被引：1，自引：1，他引：0
Libardi CA Souza GV Gáspari AF Dos Santos CF Leite ST Dias R Frollini AB Brunelli DT Cavaglieri CR Madruga VA Chacon-Mikahil MP 《Journal of sports sciences》2011,29(14):1573-1581
The purpose of this study was to evaluate the effects of moderate- to high-intensity resistance and concurrent training on inflammatory biomarkers and functional capacity in sedentary middle-aged healthy men. Participants were selected on a random basis for resistance training (n = 12), concurrent training (n = 11) and a control group (n = 13). They performed three weekly sessions for 16 weeks (resistance training: 10 exercises with 3 × 8-10 repetition maximum; concurrent training: 6 exercises with 3 × 8-10 repetition maximum, followed by 30 minutes of walking or running at 55-85% [Vdot]O(2peak)). Maximal strength was tested in bench press and leg press. The peak oxygen uptake ([Vdot]O(2peak)) was measured by an incremental exercise test. Tumour necrosis factor-α, interleukin-6 and C-reactive protein were determined. The upper- and lower-body maximal strength increase for both resistance (+42.52%; +20.9%, respectively) and concurrent training (+28.35%; +21.5%, respectively) groups (P = 0.0001).[Vdot]O(2peak) increased in concurrent training when comparing pre- and post-training (P = 0.0001; +15.6%). No differences were found in tumour necrosis factor-α and interleukin-6 for both groups after the exercise. C-reactive protein increased in resistance training (P = 0.004). These findings demonstrated that 16 weeks of moderate- to high-intensity training could improve functional capacity, but did not decrease inflammatory biomarkers in middle-aged men. 相似文献
20.
《Research quarterly for exercise and sport》2012,83(4):641-650
ABSTRACTA quick, well-timed pelvic-floor muscle contraction during physical effort is recommended for active women to prevent urine leakage. Purpose: We address two research questions: how well do future female exercise professionals contract the pelvic-floor muscles, and whether the biofeedback session is necessary to train them to contract pelvic-floor muscles? Method: Participants were 84 nulliparous future exercise professionals (age 23 ± 3 years, mean ± SD), randomly allocated into biofeedback (n = 27), usual-advice (n = 26), and control (no advice, n = 21) groups. Contraction of pelvic-floor muscles on a 4-point scale (1 = incorrect through 4 = correct) was assessed in all groups by surface electromyography (sEMG) with a vaginal probe before and after 6 weeks of intervention. Results: In pretest, almost one in five participants (17%) could not activate the pelvic floor and less than half of them (45%) presented correct technique. The technique score for the three groups was 3.1 ± 1.1 (mean ± SD). After training, both intervention groups presented better technique score by 0.6 (90% confidence limits ± 0.5) relative to the control group, and two-thirds (65%) of the intervention groups presented the correct technique. Conclusions: Future exercise professionals displayed poor skills in contracting pelvic-floor muscles. Both training interventions (with and without biofeedback) were effective for this study group. 相似文献