共查询到20条相似文献,搜索用时 15 毫秒
1.
Influence of training on the response of androgen plasma concentrations to exercise in swimmers 总被引:1,自引:0,他引:1
M. Bonifazi E. Bela G. Carli L. Lodi G. Martelli B. Zhu C. Lupo 《European journal of applied physiology》1995,70(2):109-114
In eight top-level male endurance swimmers the aerobic performance and the response to exercise of total testosterone (T), free testosterone (fT), sex hormone binding globulin (SHBG), non-SHBG-bound testosterone (NST) and cortisol (C) were evaluated during a training season. The swimmers participated in three test sessions which occurred 6, 12 and 24 weeks after the beginning of the season. During each session, after a standard warm-up, the swimmers performed a set of 15 × 200-m freestyle, with a 20-s rest between repetitions, at a predetermined individual speed. Three blood samples were collected: before warm-up, at the end of the set, and after 1 h of recovery. A few days before each session, the individual swimming velocity associated with a 4 mmol · l–1 blood lactate concentration (4) was assessed as a standard of aerobic performance. The values of 4 were lower in the second session than in the third one. The concentrations of C, which increased after the exercise, showed the highest values in the second session. The values of T and the T: SHBG ratio increased after the exercise but returned to their initial concentrations during the recovery period. The values of fT and NST increased after the exercise in the first and third sessions. In the initial two sessions, when the aerobic performance was still low, the concentrations of NST decreased to below the initial values after recovery. In session III, when the adaptation to the training workload was complete, NST returned to resting concentrations after recovery. The results would suggest that stressful stimuli produced by an increase in training volume may induce changes in androgen metabolism during exercise. In this respect, NST would appear to be a better index of metabolic response than T, T/SHBG and fT. 相似文献
2.
Hormonal responses to three training protocols in rowing 总被引:5,自引:0,他引:5
Kokalas N Tsalis G Tsigilis N Mougios V 《European journal of applied physiology》2004,92(1-2):128-132
The aim of this study was to examine the acute responses of serum growth hormone, testosterone, and cortisol to three training protocols in rowing. Six young rowers, members of the national team, carried out three frequently used protocols in rowing, i.e., an endurance, a moderate interval, and a resistance protocol, on separate days in a counterbalanced design. Blood samples were collected before, immediately after, and 4 h after exercise for the determination of growth hormone, testosterone, cortisol, and creatine kinase. All three protocols caused marked increases in growth hormone, the most spectacular being that immediately after the endurance protocol. The change in testosterone concentration immediately after the endurance protocol was significantly higher than the changes after the other two protocols. Cortisol concentration was significantly higher immediately after the endurance protocol than after the other two protocols, but remained relatively low in all cases, suggesting that these protocols did not considerably promote catabolism in muscle tissue. Based on these data, endurance training caused greater responses of the three hormones studied compared to interval or resistance training. In fact, resistance training (at intensities above 85% of 1RM) did not cause any significant changes in the three hormones. We therefore propose that evaluation of training programmes designed for elite athletes should include measurements of hormonal changes in order to ascertain that the programmes do cause the expected adaptations. 相似文献
3.
The hormonal responses of nine male, strength athletes to strength exercise were examined. The athletes performed one moderate-
and one high-intensity strength exercise workout. In the high-intensity workout, the load was 100% of each subject's three-repetition
maximum (3-RM) for squats and front squats, and 100% of each subject's six-repetition maximum (6-RM) for leg extensions. In
the moderate-intensity workout, the load was 70% of the high-intensity protocol. Rest periods between sets were 4–6 min for
both workouts. Blood samples were taken before, 30 min into, and every 15 min for the 1st h after exercise, and then 3, 7,
11, 22 and 33 h after exercise, thus allowing examination of both the acute and prolonged hormonal responses. Blood samples
were analyzed for testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, adrenocorticotrophic
hormone (ACTH), growth hormone (GH), insulin-like growth factor (IGF-1), insulin, sex hormone binding globulin, creatine kinase,
total protein, glucose and lactate. The acute responses of testosterone and cortisol were greater during the high-intensity
protocol as compared to the moderate-intensity protocol. The cortisol response was associated with an increase in ACTH concentration.
LH and FSH showed no response to either protocol. Acute GH responses were not different between protocols. There were great
inter-individual differences in acute GH responses to both protocols. There were no significant differences between protocols
with regard to prolonged responses for any hormone. In both trials, IGF-1 concentrations were significantly lower at 0800 hours
the morning after exercise as compared to concentrations found at 0800 hours the morning before exercise. The mechanisms responsible
for reducing IGF-1 concentration in these trials are unclear, and it is not known if this reduction observed 22 hours after
exercise is of physiological significance.
Accepted: 13 December 1999 相似文献
4.
Two groups of elite male swimmers were studied using a similar protocol during the winter training seasons of two consecutive
years. In the first season (September 1997–January 1998), eight male swimmers (age 19–25 years) of the Italian National Team
participated, after 12 weeks of increased training volume, in a preparatory national competition (PWC) and then, after a further
6 weeks of specific training, in the World Championships (WC, both competitions in a 50-m pool), which represented the main
competition at the end of the 18-week-long winter season. In the second season (September 1998–December 1998), a group of
ten high-level male swimmers (18–22 years) participated, after 8 weeks of increased training volume, in a preparatory national
competition (PIC) and then, after a further 6 weeks of specific training, in the Italian Championships (IC, both competitions
in a 25-m pool), the main competition at the end of the 14-week-long winter season. A tapering period lasting 1–3 weeks was
observed before the main competition in both seasons. All swimmers were competing at distances of up to 400 m; two of them
participated in the study in both seasons. The swimming velocities and post-competition blood lactate concentrations were
higher in the main competitions than in the preparatory competitions in both seasons. Pre-competition plasma cortisol (CORT)
concentrations were higher than the initial values at the beginning of the season, reaching maximal values at the preparatory
competitions and then decreasing before the main competitions in both seasons. The percentage increase in individual swimming
velocity from the preparatory to the main competition was positively correlated with the corresponding increase in post-competition
blood lactate (r=0.63, P=0.046) in the 1997 season (WC), and negatively correlated with the corresponding decrease in pre-competition CORT concentration
(r=−0.66, P=0.019) in the 1998 season (IC). Our results indicate that a decrease in pre-competition CORT could be a prerequisite for
an improvement in swimming performance.
Accepted: 9 March 2000 相似文献
5.
Henning Budde Sascha Pietrassyk-Kendziorra Sebastian Bohm Claudia Voelcker-Rehage 《Neuroscience letters》2010
Little is known about the influence of physical and cognitive stress on the concentration of steroid hormones (SHs) in a school setting. Forty high school students from the 9th grade were randomly assigned to two intervention groups: physical and cognitive stress. Saliva collection took place before (pre-test) and after (post-test) 12 min of high intensity exercise in a defined heart rate (HR) interval (70–85% HR max; n = 19) and cognitive testing (Letter Digit Span and d2-test, n = 21), respectively. Saliva was analyzed for testosterone (T) and cortisol (C). Results indicated a significant increase of T and C due to a physical but not cognitive stressor. Thus, only the physical stressor was capable of activating the hypothalamic–pituitary–adrenal (HPA) and the hypothalamic–pituitary–gonadal (HPG) axis. 相似文献
6.
R. C. Hickson J. M. Hagberg R. K. Conlee D. A. Jones A. A. Ehsani W. W. Winder Ph.D. 《European journal of applied physiology》1979,41(3):211-219
Summary The effects of 9 weeks of training on responses of plasma hormones to swimming were studied in eight competitive swimmers who had not trained for several months. Two types of swimming tests were used: (1) 200 yd, a high intensity, exhausting type of exercise in which maximal effort was required both before and after training, and (2) 1000 yd, a pace type of exercise in which subjects swam as fast as possible prior to training and at the same rate after training. Plasma levels of glucagon increased and of insulin decreased during 1000 yd of swimming, but were not altered by 200 yd of swimming. No training effects were apparent in responses of plasma insulin and glucagon to these short-term, high intensity exercise tests. During the 1000 yd swim, plasma adrenaline was 0.8 ng/ml before vs. 0.1 ng/ml after training. Plasma noradrenaline response decreased from 3.4 to 1.2 ng/ml as a result of training. In the 200 yd swim, adrenaline, but not noradrenaline, was lower after training.R. C. Hickson and R. K. Conlee were postdoctoral research trainees supported by NIH Training Grant AM-05341.J. M. Hagberg was a postdoctoral research trainee supported by NIH Training Grant HL-07081. 相似文献
7.
Patrick Pelayo Iñigo Mujika Michel Sidney Jean-Claude Chatard 《European journal of applied physiology》1996,74(1-2):107-113
The purpose of this study was to relate measurements of blood lactate concentration, performance during a maximal anaerobic lactic test (MANLT) and training loads during a 23-week swimming season. Six elite 200-m freestyle male swimmers [mean age 19.5 (SD 1.6) years, height 184 (SD 5) cm and body mass 77.7 (SD 9.0) kg], participated in the study. The MANLT consisted of four all-out 50-m swims interspersed with 10-s recovery periods. Blood lactate concentrations were determined at 3 and 12-min post-exercise and were performed on weeks 2, 6,10,14,18 and 21. Swimmers participated in 200-m freestyle competitions on weeks 1, 7,13 and 23 (national championships). During weeks 1–10, training mostly involved aerobic exercise, while during weeks, 11–23, it involved anaerobic exercise. At 3-min and 12-min post-MANLT lactate concentrations varied throughout the season [range from 14.9 (SD 1.2) to 18.7 (SD 1.0) mmol·l–1] but demonstrated non-systematic variations. In contrast, the percentage of mean blood lactate decrease (% [La-]recovery) between min 3 and min 12 of the passive recovery post-MANLT increased from week 2 to 10 with aerobic training and decreased from week 10 to 21 with anaerobic training. The MANLT performance improved continuously throughout the season, while competition performance improved during the first three competitions but declined in the final championships, coinciding with the lowest % [La-]recovery and signs of overtraining, such as bad temper and increased sleeping heart rate. The results of this study indicated that % [La-]recovery could be an efficient marker for monitoring the impact of aerobic and anaerobic training and avoiding overtraining in elite 200-m swimmers. 相似文献
8.
Volek JS Ratamess NA Rubin MR Gómez AL French DN McGuigan MM Scheett TP Sharman MJ Häkkinen K Kraemer WJ 《European journal of applied physiology》2004,91(5-6):628-637
To determine the effects of creatine supplementation during short-term resistance training overreaching on performance, body composition, and resting hormone concentrations, 17 men were randomly assigned to supplement with 0.3 g/kg per day of creatine monohydrate (CrM: n=9) or placebo (P: n=8) while performing resistance exercise (5 days/week for 4 weeks) followed by a 2-week taper phase. Maximal squat and bench press and explosive power in the bench press were reduced during the initial weeks of training in P but not CrM. Explosive power in the bench press, body mass, and lean body mass (LBM) in the legs were augmented to a greater extent in CrM (P0.05) by the end of the 6-week period. A tendency for greater 1-RM squat improvement (P=0.09) was also observed in CrM. Total testosterone (TT) and the free androgen index (TT/SHBG) decreased in CrM and P, reaching a nadir at week 3, whereas sex hormone binding globulin (SHBG) responded in an opposite direction. Cortisol significantly increased after week 1 in CrM (+29%), and returned to baseline at week 2. Insulin was significantly depressed at week 1 (–24%) and drifted back toward baseline during weeks 2–4. Growth hormone and IGF-I levels were not affected. Therefore, some measures of muscular performance and body composition are enhanced to a greater extent following the rebound phase of short-term resistance training overreaching with creatine supplementation and these changes are not related to changes in circulating hormone concentrations obtained in the resting, postabsorptive state. In addition, creatine supplementation appears to be effective for maintaining muscular performance during the initial phase of high-volume resistance training overreaching that otherwise results in small performance decrements. 相似文献
9.
Summary To analyse the relative significance of exercise intensity and duration as well as of performance capacity, hormone changes were recorded in 16 male rowers in two experiments separated by a year. The test exercises consisted of 7-min (at the supramaximal intensity) and 40-min rowing (at the level of the anaerobic threshold) on a rowing apparatus. In addition, somatotropin and cortisol responses were estimated in rowing for 8 × 2000 m in 14 rowers of national class. All three tests caused significant increases in somatotropin and cortisol concentrations in the blood. Follitropin concentrations were elevated in the 7-min exercise test in the second experiment and in the 40-min exercise test in both experiments. Lutropin and progesterone concentrations increased during the more prolonged exercise in the first experiment. No common change was found in testosterone concentrations. Cortisol and somatotropin responses to the 40-min rowing test at anaerobic threshold were more pronounced than to the 7-min exercise test at supramaximal intensity. When the rowers achieved a national class level of performance (the second experiment) the hormone responses to 7-min supramaximal exercise were increased. During the 8 × 2000-m rowing test cortisol but not somatotropin concentration increased to an extremely high level in the rowers of national class. It is concluded that in strenuous exercise cortisol and somatotropin responses were triggered by the exercise intensity threshold. The exact magnitude of the response would seem to have depended on additional stimuli caused by exercise duration and on possibility of mobilizing hormone reserves. 相似文献
10.
The adrenocortical and gonadal responses of 14 male monkeys were evaluated during four experimental conditions in order to evaluate the influence of social interactions on endocrine responsiveness. Plasma hormone levels were determined during the establishment of social relations, after 60-min exposures to a novel environment, after 60-min exposures to a snake, and 60 min after ACTH administration. Both adrenal and gonadal secretion changed significantly during the first day after social relations were established, although only dominant males showed increases in testosterone, whereas cortisol levels rose in all subjects. Increases in cortisol, but not testosterone, were also observed following exposure to novelty or a snake. The presence of a social partner reduced signs of behavioral disturbance during these test conditions, although the adrenal responses were equivalent or greater than when tested alone. This finding qualifies earlier research which indicated that social support was beneficial for reducing stress when squirrel monkeys were tested in larger groups in their home environment. 相似文献
11.
Grant O. McCaulley Jeffrey M. McBride Prue Cormie Matthew B. Hudson James L. Nuzzo John C. Quindry N. Travis Triplett 《European journal of applied physiology》2009,105(5):695-704
The purpose of the current study was to determine the acute neuroendocrine response to hypertrophy (H), strength (S), and
power (P) type resistance exercise (RE) equated for total volume. Ten male subjects completed three RE protocols and a rest
day (R) using a randomized cross-over design. The protocols included (1) H: 4 sets of 10 repetitions in the squat at 75% of
1RM (90 s rest periods); (2) S: 11 sets of three repetitions at 90% of 1RM (5 min rest periods); and (3) P: 8 sets of 6 repetitions
of jump squats at 0% of 1RM (3 min rest periods). Total testosterone (T), cortisol (C), and sex hormone binding globulin (SHBG)
were determined prior to (PRE), immediately post (IP), 60 min post, 24 h post, and 48 h post exercise bout. Peak force, rate
of force development, and muscle activity from the vastus medialis (VM) and biceps femoris (BF) were determined during a maximal
isometric squat test. A unique pattern of response was observed in T, C, and SHBG for each RE protocol. The percent change
in T, C, and SHBG from PRE to IP was significantly (p ≤ 0.05) greater in comparison to the R condition only after the H protocol. The percent of baseline muscle activity of the
VM at IP was significantly greater following the H compared to the S protocol. These data indicate that significant acute
increases in hormone concentrations are limited to H type protocols independent of the volume of work competed. In addition,
it appears the H protocol also elicits a unique pattern of muscle activity as well. RE protocols of varying intensity and
rest periods elicit strikingly different acute neuroendocrine responses which indicate a unique physiological stimulus. 相似文献
12.
Kraemer RR Acevedo EO Synovitz LB Hebert EP Gimpel T Castracane VD 《European journal of applied physiology》2001,86(1):85-91
The purpose of the study was to investigate the responses of leptin and steroid hormones to maximal exercise in adolescent
female runners over a competitive season. Seven adolescent female distance runners completed three testing trials during weeks
1, 4 and 7 of their high-school track season. Blood samples were collected before and after a discontinuous graded exercise
test to exhaustion (GXT) for each trial. Tests were administered during the subjects' normal training time (3:30 p.m.–5:00 p.m.).
Compared to week 1, peak O2 uptake rose significantly during the season and was 10% and 7% higher at weeks 4 and 7, respectively. Levels of dehydroepiandrosterone
(DHEA), dehydroepiandrosterone sulfate (DHEAS), cortisol, testosterone, and leptin increased significantly in response to
the graded exercise tests. Testosterone levels were also changed over the course of the study. Resting testosterone levels
and testosterone responses to exercise in weeks 4 and 7 were both higher than in week 1. Resting concentrations and acute
increases of the other hormones were not changed over the season. It appears, therefore, that DHEA, DHEAS, cortisol, testosterone
and leptin concentrations increase in response to running in adolescent female runners. Data also suggest that training and/or
maturation increases resting testosterone concentrations and testosterone responses to running in adolescent female runners
during a training season.
Electronic Publication 相似文献
13.
Hormonal responses to whole-body vibration in men 总被引:7,自引:0,他引:7
Bosco C Iacovelli M Tsarpela O Cardinale M Bonifazi M Tihanyi J Viru M De Lorenzo A Viru A 《European journal of applied physiology》2000,81(6):449-454
The aim of this study was to evaluate the acute responses of blood hormone concentrations and neuromuscular performance following
whole-body vibration (WBV) treatment. Fourteen male subjects [mean (SD) age 25 (4.6) years] were exposed to vertical sinusoidal
WBV, 10 times for 60 s, with 60 s rest between the vibration sets (a rest period lasting 6 min was allowed after 5 vibration
sets). Neuromuscular performance tests consisting of counter-movement jumps and maximal dynamic leg presses on a slide machine,
performed with an extra load of 160% of the subjects body mass, and with both legs were administered before and immediately
after the WBV treatment. The average velocity, acceleration, average force, and power were calculated and the root mean square
electromyogram (EMGrms) were recorded from the vastus lateralis and rectus femoris muscles simultaneously during the leg-press
measurement. Blood samples were also collected, and plasma concentrations of testosterone (T), growth hormone (GH) and cortisol
(C) were measured. The results showed a significant increase in the plasma concentration of T and GH, whereas C levels decreased.
An increase in the mechanical power output of the leg extensor muscles was observed together with a reduction in EMGrms activity.
Neuromuscular efficiency improved, as indicated by the decrease in the ratio between EMGrms and power. Jumping performance,
which was measured using the counter-movement jump test, was also enhanced. Thus, it can be argued that the biological mechanism
produced by vibration is similar to the effect produced by explosive power training (jumping and bouncing). The enhancement
of explosive power could have been induced by an increase in the synchronisation activity of the motor units, and/or improved
co-ordination of the synergistic muscles and increased inhibition of the antagonists. These results suggest that WBV treatment
leads to acute responses of hormonal profile and neuromuscular performance. It is therefore likely that the effect of WBV
treatment elicited a biological adaptation that is connected to a neural potentiation effect, similar to those reported to
occur following resistance and explosive power training. In conclusion, it is suggested that WBV influences proprioceptive
feedback mechanisms and specific neural components, leading to an improvement of neuromuscular performance. Moreover, since
the hormonal responses, characterised by an increase in T and GH concentration and a decrease in C concentration, and the
increase in neuromuscular effectiveness were simultaneous but independent, it is speculated that the two phenomena might have
common underlying mechanisms.
Accepted: 8 September 1999 相似文献
14.
Peter R. J. Reaburn Laurel Traeger Mackinnon 《European journal of applied physiology》1990,61(3-4):246-250
Summary The purpose of this study was to determine the effect of age on three blood lactate parameters following maximal sprint swimming. The parameters examined were maximal blood lactate concentration, time to reach maximal blood lactate concentration, and half recovery time to baseline lactate concentration. These parameters were examined in 16 male competitive masters swimmers (n=4 for each age group: 25–35, 36–45, 46–55, and 56 plus years) during both passive and active recovery following a maximal 100 m freestyle sprint. Passive recovery consisted of 60 min sitting in a comfortable chair and active recovery consisted of a 20-min swim at a self-selected pace. Capillary blood samples were obtained every 2 min up to 10 min of recovery then at regular intervals to the end of the recovery period. Curves of blood lactate concentration against time were drawn and the three parameters determined for each condition for each subject. There were no significant differences between age groups in any of the lactate parameters examined. A significant difference (P<0.05) was noted in each of the parameters between active and passive recovery over all age groups. As expected, active recovery produced lower maximal blood lactate concentrations, lower time to maximal blood lactate values, and lower half recovery times. These data suggest that intensive swimming training may prevent or delay the decline with age in the physiological factors affecting blood lactate values following a maximal sprint swim. Older sprint swimmers appeared to be capable of producing and removing lactic acid at the same rate as younger swimmers. These data suggest that the age-related decline in swim-sprint performance may be due to factors other than changes in anaerobic glycolytic capacity. 相似文献
15.
Wells GD Plyley M Thomas S Goodman L Duffin J 《European journal of applied physiology》2005,94(5-6):527-540
The efficiency of the respiratory system presents significant limitations on the bodys ability to perform exercise due to the effects of the increased work of breathing, respiratory muscle fatigue, and dyspnoea. Respiratory muscle training is an intervention that may be able to address these limitations, but the impact of respiratory muscle training on exercise performance remains controversial. Therefore, in this study we evaluated the effects of a 12-week (10 sessions week–1) concurrent inspiratory and expiratory muscle training (CRMT) program in 34 adolescent competitive swimmers. The CRMT program consisted of 6 weeks during which the experimental group (E, n=17) performed CRMT and the sham group (S, n=17) performed sham CRMT, followed by 6 weeks when the E and S groups performed CRMT of differing intensities. CRMT training resulted in a significant improvement in forced inspiratory volume in 1 s (FIV1.0) (P=0.050) and forced expiratory volume in 1 s (FEV1.0) (P=0.045) in the E group, which exceeded the S groups results. Significant improvements in pulmonary function, breathing power, and chemoreflex ventilation threshold were observed in both groups, and there was a trend toward an improvement in swimming critical speed after 12 weeks of training (P=0.08). We concluded that although swim training results in attenuation of the ventilatory response to hypercapnia and in improvements in pulmonary function and sustainable breathing power, supplemental respiratory muscle training has no additional effect except on dynamic pulmonary function variables. 相似文献
16.
Van de Velde A De Mey K Maenhout A Calders P Cools AM 《Journal of Athletic Training》2011,46(2):160-7; discussion 168-9
Context:
Swimming requires well-balanced scapular-muscle performance. An additional strength-training program for the shoulders is pursued by swimmers, but whether these muscle-training programs need to be generic or specific for endurance or strength is unknown.Objective:
To evaluate isokinetic scapular-muscle performance in a population of adolescent swimmers and to compare the results of training programs designed for strength or muscle endurance.Design:
Controlled laboratory study.Setting:
University human research laboratory.Patients or Other Participants:
Eighteen adolescent swimmers.Intervention(s):
Each participant pursued a 12-week scapular-training program designed to improve either muscle strength or muscle endurance.Main Outcome Measure(s):
Bilateral peak force, fatigue index, and protraction/retraction strength ratios before and after the scapular-training program.Results:
Scapular protraction/retraction ratios were slightly higher than 1 (dominant side = 1.08, nondominant side = 1.25, P = .006). Side-to-side differences in retraction strength were apparent both before and after the training program (P = .03 and P = .05, respectively). After the training program, maximal protraction (P < .05) and retraction (P < .01) strength improved on the nondominant side. Peak force and fatigue index were not different between the training groups. The fatigue indexes for protraction on both sides (P < .05) and retraction on the nondominant side (P = .009) were higher after the training program.Conclusions:
We describe the scapular-muscle characteristics of a group of adolescent swimmers. Both muscle-strength and muscle-endurance programs improved absolute muscle strength. Neither of the strength programs had a positive effect on scapular-muscle endurance. Our results may be valuable for coaches and physiotherapists when they are designing exercise programs for swimmers. 相似文献17.
K. Collomp S. Ahmaidi J. C. Chatard M. Audran Ch. Préfaut 《European journal of applied physiology》1992,64(4):377-380
Summary The influence of specific training on benefits from caffeine (Caf) ingestion was examined during a sprint test in a group of highly trained swimmers (T) and compared with the response of a group of untrained occasional swimmers (UT). Seven T and seven UT subjects swam freestyle two randomly assigned 2 × 100 m distances, at maximal speed and separated by 20 min of passive recovery, once after Caf (250 mg) and once after placebo (Pla) ingestion. Anaerobic capacity was assessed by the mean velocity (meters per second) during each 100 m and blood was sampled from the fingertip just before and 1, 3, 5, 7, and 9 min after each 100 m for resting and maximal blood lactate concentration ([1a–]b, max) determination. The [[1a–]b, max was significantly enhanced by Caf in both T and UT subjects (P<0.01). However, only T subjects exhibited significant improvement in their swimming velocity (P<0.01) after Caf or any significant impairment during the second 100 m. In light of these results, it appears that specific training is necessary to benefit from the metabolic adaptations induced by Caf during supramaximal exercise requiring a high anaerobic capacity. 相似文献
18.
Kazushige Goto Naokata Ishii Tomohiro Kizuka Robert R. Kraemer Yuzo Honda Kaoru Takamatsu 《European journal of applied physiology》2009,106(5):731-739
We examined hormonal responses to slow movement exercise involving concentric (CON) and eccentric (ECC) actions. Nine men
performed knee extension exercises: (1) low-intensity exercise with slow CON contractions (5-1; 5 s for CON and 1 s for ECC);
(2) low-intensity exercise with slow ECC contractions (1-5; 1 s for CON and 5 s for ECC); (3) low-intensity exercise with
slow CON and ECC contractions (3-3; 3 s for each contraction); and (4) high-intensity exercise at normal velocity (1-1; 1 s
for each contraction). Lactate concentration was significantly higher after the 5-1 than after the 1-5 (P < 0.05). Slow movement exercises significantly raised the concentrations of plasma epinephrine, serum growth hormone, and
free testosterone (P < 0.05). Serum growth hormone concentration increased to a greater extent after the three slow movement trials compared with
the normal movement trial (1-1). However, serum cortisol concentration was significantly higher after the 5-1 than after the
1-5 and 1-1 (P < 0.05). Average throughout the exercise session (divided by the time to complete exercise session) was significantly higher in the 1-1 (P < 0.05), with no significant difference among the slow movement trials. In conclusion, low-intensity exercises with slow
movement acutely increased anabolic hormone concentrations regardless of the time to complete CON and ECC actions. In contrast,
low-intensity exercise with slower ECC action stimulated smaller changes in lactate and cortisol compared with low-intensity
exercise with slower CON action. 相似文献
19.
Blair T. Crewther Tim Lowe Robert P. Weatherby Nicholas Gill 《European journal of applied physiology》2009,105(6):919-927
This study examined the effect of cycle sprints as a potentiating stimulus for power and strength adaptation in semi-elite
athletes. Eighteen rugby players were assigned into training groups that completed either a 40-s cycle sprint (TSPRINT) or rested (TCONTROL) before each workout (n = 6–8) of a 4-week programme. Squat jump (SJ) peak power (PP) and mean power (MP), and box squat (BS) one repetition maximum
(1RM) strength were assessed every workout. Saliva was collected across each workout and assayed for testosterone (Sal-T)
and cortisol (Sal-C). The TSPRINT and TCONTROL groups both showed significant improvements in SJ PP (8.2 ± 2.9 vs. 11.9 ± 3.6%), SJ MP (11.8 ± 2.6 vs. 18.6 ± 4.8%) and
BS 1RM (20.5 ± 2.6 vs. 23.2 ± 1.3%), respectively. However, there were no group differences in training adaptation, workout
performance or the workout hormonal responses. As a combined group (all players), significant relationships were demonstrated
between resting Sal-T and/or Sal-C concentrations and absolute SJ power (r = 0.20–0.30) and BS strength (r = 0.36–0.44) across all workouts. For individual players, the respective relationships with SJ power (r = 0.22–0.42) and BS strength (r = 0.41–0.49) were, on average, found to be stronger. In conclusion, leg workouts performed with or without prior cycle sprints
can produce similar power and strength improvements in semi-elite rugby players. Resting salivary hormone concentrations appear
important for workout performance, especially for individuals, thereby potentially moderating training adaptation. 相似文献