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1.
Abstract

The purpose of this study was to observe the effects of a submaximal isometric training program on estimation capacity at 25, 50, and 75% of maximal contraction in isometric action and at two angular velocities. The second purpose was to study the variability of isometric action. To achieve these purposes, participants carried out an isokinetic extension movement of the dominant lower limb during six test sessions and nine training sessions. Following the training program, estimation capacity in the different actions did not improve. However, an improvement in performance was observed with a reduction in the variability of submaximal isometric actions. The proprioceptors activated in isometric action seemed to adapt to the training program itself, which would promote better adaptation by a greater solicitation of internal feedback.  相似文献   

2.
Abstract

The purpose of this study was twofold: to determine which exercise program was most effective in producing a static strength gain and to determine the relationship between static strength and speed of movement. Seventy-two eighth grade girls were divided into two experimental groups one using an isometric exercise program, the other using an isotonic program. A control group played lead-up games during the experimental period. Strength and speed of the arm and shoulder girdle were both measured by three tests. Prior to training, correlations indicated a rather high relationship between static strength, and speed of a dominant arm movement. Following training there was little relationship between static strength, and speed of a specific arm movement. The results of the training program indicated an increase in mean performance in all three groups with the isotonic group being superior.  相似文献   

3.
Abstract

The purpose of the study was to investigate the effect of a 2-min. isometric exercise training program on force and fatigue in a skeletal muscle. The subjects (N=60) were divided into two equal groups, control and experimental. The control group was tested twice, once at the beginning of the experiment and again after 20 days. The subjects in the experimental group were tested before embarked on a 20-day period of isometric training. held the tension for 2 min. in the morning and again in the afternoon. Periodic tests were on the 5th, 10th, 15th, and 20th days. Large gains of initial strength were recorded on the 5th day. Isometric training continued beyond five days produced no significant gains in initial strength althoughe was a significant increase in isometric endurance. Isometric exercise continued longer than 15 days resulted in a significant decrease in initial strength and isometric endurance.  相似文献   

4.
Abstract

This study was made to determine the influence of five selected motive-incentive conditions upon the effectiveness of a 6-week isometric training program for the development of strength in the elbow flexor muscle group. Data were obtained from an initial test, from each training session, and from a final test. The mean gains in best strength scores from the initial to the final test were statistically significant (p = .05) for all five motive-incentive groups. No significant differences (p = .05) were found between the mean of the scores for the five motive inventive groups obtained during the first training session, during the last training session, from the final test, and from the cumulative scores for the 12 training sessions.  相似文献   

5.
The neural mechanisms explaining strength increase following mental training by motor imagery (MI) are not clearly understood. While gains are mostly attributed to cortical reorganization, the sub-cortical adaptations have never been investigated. The present study investigated the effects of MI training on muscle force capacity and the related spinal and supraspinal mechanisms. Eighteen young healthy participants (mean age: 22.5?±?2.6) took part in the experiment. They were distributed into two groups: a control group (n?=?9) and an MI training group (n?=?9). The MI group performed seven consecutive sessions (one per day) of imagined maximal isometric plantar flexion (4 blocks of 25 trials per session). The control group did not engage in any physical or mental training. Both groups were tested for the isometric maximal plantar flexion torque (MVC) and the rate of torque development (RTD) before and after the training session. In addition, soleus and medial gastrocnemius spinal and supraspinal adaptations were assessed through the recording of H-reflexes and V-waves, with electrical stimulations of the posterior tibial nerve evoked at rest and during MVC, respectively. After one week, only the MI training group increased both plantar flexion MVC and RTD. The enhancement of muscle torque capacity was accompanied by significant increase of electromyographic activity and V-wave during MVC and of H-reflex at rest. The increased cortical descending neural drive and the excitability of spinal networks at rest could explain the greater RTD and MVC after one week of MI training.  相似文献   

6.
文章以山西省优秀青少年蹦床运动员为研究对象,运用文献资料法、问卷调查法、专家访谈法、现场观察法、数理统计法等研究方法,对山西省青少年蹦床技术训练赛前强化期中的负荷量与负荷强度进行了研究,进而为山西省青少年蹦床技术训练提供有价值的理论参考。研究结果表明：（1）山西省青少年蹦床运动员竞赛期训练内容主要分为单个动作、组合动作、分段动作与成套动作。（2）评价负荷量度的指标包括负荷量与负荷强度,负荷量以单个动作训练的次数、动作组合练习的次数、分段练习的次数以及成套动作练习的次数表示,强度以动作的难度值表示。（3）赛前强化期抠动作质量,以组合动作练习为主,加大了第二套分段动作的数量,主要提高动作的稳定性,负荷量适中,平均周负荷量为1200次;强度较大,以组合与分段动作难度为主。主要以单个与成套动作循环训练法、成套动作分段训练法与超长成套动作训练法为主。（4）甲2组运动员自选套以两周团身,转体动作多为180度,乙组运动员自选套以单周背弹或腹弹动作,很难完成两周动作。  相似文献   

7.
Abstract

Seven untrained, nonathletic women 19–42 years of age participated in a daily five-minute rope skipping program during a four-week period. As a result of this training program, there was a significant improvement in physical work capacity as judged by pulse response to a standardized submaximal work load, or by the estimated maximal oxygen uptake based upon the pulse response to submaximal ergometer work according to the Åstrand nomogram. It is suggested that rope skipping can be adopted as a simple method of improving the physical work capacity of a large segment of our population.  相似文献   

8.
The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 +/- 6.1 years (mean +/- s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2-3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 +/- 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption (VO2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55-75 years.  相似文献   

9.
Seven elite male cross-country skiers trained for 3 weeks at an altitude of 1900 m. Haemoglobin concentration ([Hb]), haematocrit (Hct) (obtained from venous blood), maximal oxygen uptake (VO2 max) and energy expenditure during a standard submaximal workload were measured before and after training at altitude, and 1 year later while training at sea level (control). Both [Hb] and Hct increased significantly, and the skiers with the lowest initial [Hb] and Hct experienced the largest increases during training at altitude. The increase in blood lactate (BLa) concentration (using haemolysed capillary blood) during a standard submaximal exercise test was significantly lower after training at altitude than before it or 1 year later (control). A significant correlation was found between the magnitude of increase in [Hb] and Hct and the difference in the lactate response to the standard submaximal workload pre- and post-altitude training. Although VO2 max remained unchanged, lower BLa concentration during the submaximal test probably reflects an improved ability to exercise at higher submaximal workloads shortly after training at altitude compared with pre-altitude training. It is suggested that subjects with low initial [Hb] and Hct improve their aerobic performance capacity most during altitude training.  相似文献   

10.
Abstract

Male university students (N = 54) engaged in an 8-week training program with sessions held three times per week. Each session consisted of one “all-out” bout of right elbow flexion on an arm lever ergometer against a resistance of 11.03 lbs. at a work rate of 40 repetitions per minute. Following the training phase of the study, the subjects were randomly assigned to three experimental groups and ceased training for either 8, 10, or 12 weeks. At the conclusion of the inactivity period, each subject retrained until his peak performance of the training program had been equaled or exceeded. The analysis of data revealed that no difference existed among the groups: (a) at the beginning of the training program, (b) at the termination of the training program, (c) following the various inactivity periods, and (d) in the number of sessions needed to retrain to the peak performance attained during the training period. The within-group analysis indicated that each group had experienced: (a) significant muscular endurance development during the training period, (b) significant loss of endurance during the period of inactivity, and (c) significant retention of the newly acquired endurance over the inactivity period. Peak performance during the retraining phase was achieved in approximately one-fourth the number of training sessions initially required to attain the same level during the developmental phase.  相似文献   

11.
The purpose of the present investigation was to compare the content of 8 weeks of training in young endurance-trained male and female runners and study the potential impact of this training content on performance. Fourteen men and 11 women performed two criterion exercises until exhaustion on an outdoor track before and after the 8-week training period. The first test was a graded exercise to determine maximal aerobic velocity (Mav), the velocity at the lactate concentration threshold (v-Tlac), and the velocity at delta 50 (v delta50: the velocity halfway between Mav and v-Tlac). The second test was a constant run at v delta50 to determine the time to exhaustion at this velocity (tlimv delta50). Training logs were used to monitor the self-directed training sessions. The results showed that the women had a lower training volume but trained at higher exercise velocities than the men. However they presented similar values as the men for expected temporary performance capacity and did not improve their performance (Mav and tlimv delta50) over the 8-week period. After the training period, only v-Tlac (absolute and relative values) was slightly but significantly increased by training. These results could be due to the fact that both men and women did not train more than 10% of the total distance run at exercise velocities equal to or higher than their Mav and did not increase their training load during the 8-week training period. We suggest that changes in training content during the season, such as severe (long-duration or high-intensity) training sessions, may have improved their performance capacity.  相似文献   

12.
The purpose of the present investigation was to compare the content of 8 weeks of training in young endurance-trained male and female runners and study the potential impact of this training content on performance. Fourteen men and 11 women performed two criterion exercises until exhaustion on an outdoor track before and after the 8-week training period. The first test was a graded exercise to determine maximal aerobic velocity (Mav), the velocity at the lactate concentration threshold (v-Tlac), and the velocity at delta 50 (vΔ50: the velocity halfway between Mav and v-Tlac). The second test was a constant run at vΔ50 to determine the time to exhaustion at this velocity (tlimvΔ50). Training logs were used to monitor the self-directed training sessions. The results showed that the women had a lower training volume but trained at higher exercise velocities than the men. However, they presented similar values as the men for expected temporary performance capacity and did not improve their performance (Mav and tlimvΔ50) over the 8-week period. After the training period, only v-Tlac (absolute and relative values) was slightly but significantly increased by training. These results could be due to the fact that both men and women did not train more than 10% of the total distance run at exercise velocities equal to or higher than their Mav and did not increase their training load during the 8-week training period. We suggest that changes in training content during the season, such as severe (long-duration or high-intensity) training sessions, may have improved their performance capacity.  相似文献   

13.
BackgroundHigh-intensity interval training (HIIT) induces similar or even superior adaptations compared to continuous endurance training. Indeed, just 6 HIIT sessions over 2 weeks significantly improves maximal oxygen uptake (VO2max), submaximal exercise fat oxidation, and endurance performance. Whether even faster adaptations can be achieved with HIIT is not known. Thus, we aimed to determine whether 2 sessions of HIIT per day, separated by 3 h, every other day for 5 days (double HIIT (HIIT-D), n = 15) could increase VO2max, submaximal exercise fat oxidation, and endurance capacity as effectively as 6 sessions of HIIT over 2 weeks (single HIIT (HIIT-S), n = 13).MethodsEach training session consisted of 10 × 60 s of cycling at 100% of VO2max interspersed with 75 s of low-intensity cycling at 60 watt (W). Pre- and post-training assessments included VO2max, time to exhaustion at ∼80% of VO2max, and 60-min cycling trials at ∼67% of VO2max.ResultsSimilar increases (p < 0.05) in VO2max (HIIT-D: 7.7% vs. HIIT-S: 6.0%, p > 0.05) and endurance capacity (HIIT-D: 80.1% vs. HIIT-S: 79.2%, p > 0.05) were observed. Submaximal exercise carbohydrate oxidation was reduced in the 2 groups after exercise training (HIIT-D: 9.2%, p = 0.014 vs. HIIT-S: 18.8%, p = 0.012) while submaximal exercise fat oxidation was significantly increased in HIIT-D (15.5%, p = 0.048) but not in HIIT-S (9.3%, p = 0.290).ConclusionSix HIIT sessions over 5 days was as effective in increasing VO2max and endurance capacity and was more effective in improving submaximal exercise fat oxidation than 6 HIIT sessions over 2 weeks.  相似文献   

14.
The purpose of this study was to examine the effects of a 10 week contrast training (CT) programme (isometric + plyometric) on jumping, sprinting abilities and agility performance in prepubertal basketball players. Fifty-eight children from a basketball academy (age: 8.72 ± 0.97 years; body mass index: 17.22 ± 2.48 kg/m2) successfully completed the study. Participants were randomly assigned to experimental groups (EG, n = 30) and control groups (CG, n = 28). The CT programme was included in the experimental group’s training sessions – twice a week – as part of their usual weekly training regime. This programme included 3 exercises: 1 isometric and 2 plyometric. Jumping, sprinting and agility performance were assessed before and after the training programme. Significant differences were found in posttest between EG and CG in sprint and T-test: EG showed better results than CG. Furthermore, there were significant differences in posttest-pretest between EG and CG in squat jump, countermovement jump, drop jump, sprint and T-test with the EG showing better results than CG. The CT programme led to increases in vertical jump, sprint and agility levels, so that the authors suggest that prepubertal children exhibit high muscular strength trainability.  相似文献   

15.
The purpose of this study was to investigate the effects of using an internal versus external focus of attention during resistance training on muscular adaptations. Thirty untrained college-aged men were randomly assigned to an internal focus group (INTERNAL) that focused on contracting the target muscle during training (n?=?15) or an external focus group (EXTERNAL) that focused on the outcome of the lift (n?=?15). Training for both routines consisted of 3 weekly sessions performed on non-consecutive days for 8 weeks. Subjects performed 4 sets of 8–12 repetitions per exercise. Changes in strength were assessed by six repetition maximum in the biceps curl and isometric maximal voluntary contraction in knee extension and elbow flexion. Changes in muscle thickness for the elbow flexors and quadriceps were assessed by ultrasound. Results show significantly greater increases in elbow flexor thickness in INTERNAL versus EXTERNAL (12.4% vs. 6.9%, respectively); similar changes were noted in quadriceps thickness. Isometric elbow flexion strength was greater for INTERNAL while isometric knee extension strength was greater for EXTERNAL, although neither reached statistical significance. The findings lend support to the use of a mind–muscle connection to enhance muscle hypertrophy.  相似文献   

16.
Abstract

The purpose of this study was to characterize changes and variability in test performance of swimmers within and between seasons over their elite competitive career. Forty elite swimmers (24 male, 16 female) performed a 7×200-m incremental swimming step test several times each 6-month season (10±5 tests, spanning 0.5–6.0?y). Mixed linear modeling provided estimates of percent change in the mean and individual responses (within-athlete variation as a coefficient of variation) for measures based on submaximal performance (fixed 4-mM lactate), maximal performance (the seventh step) and lean mass (from skinfolds and body mass). Submaximal and maximal swim speed increased within each season from pre to taper phase by ～2.2% for females and ～1.5% for males (95% confidence limits ±1.0%), with variable contributions from stroke rate and stroke length. Most of the gains in speed were lost in the off-season, leaving a net average annual improvement of ～1.0% for females and ～0.6% for males (±1.0%). For submaximal and maximal speed, individual variation between phases was ±2.2% and the typical measurement error was ±0.80%. Step test and anthropometric measures can be used to confidently monitor progressions in swimmers in an elite training program within and between seasons.  相似文献   

17.
Attaching elastic tubes (ETs) to resistance training machines can affect the exercise load profile. The purpose of this study was to assess the training effects of added ETs, which were strategically attached to provide additional loads only during the deceleration phase of the knee extension exercise. Twenty-two healthy participants, assigned to either an experimental group (with ETs) or a control group (without ETs), participated in a 12-week strength-training program using a knee extension exercise machine. The acceleration effects were quantified and a method of attaching the ETs to the knee extension machine was developed. The effects of the added ETs were analysed by testing dynamic and isometric maximum contractions at four knee flexion angles (10°, 30°, 50°, and 80°). Analyses of covariance with the initial values as the covariate were used to examine the ET effects. A greater increase in isometric maximum strength was found in the experimental group than in the control group at knee flexion angles of 10° [effect size (ES) = 2.25] and 30° (ES = 1.18). No significant difference in the dynamic maximum strength was found between the groups. The use of ETs increased strength at smaller knee flexion angles with quadriceps that were relatively short.  相似文献   

18.
Abstract

The research was undertaken to determine if an increase in the duration of a sustained voluntary isometric contraction is more closely related to changes in cardiovascular endurance or changes in strength. Subjects (N = 24) were tested before and after a training program to determine their endurance (oxygen consumption) and strength. The training program consisted of one daily sustained voluntary isometric contraction of the left forearm flexors at a prescribed percentage of the subject's maximum isometric strength. When the mean duration of contractions for each group showed a significant increase, training ceased.

The groups which trained with contractions of 50, 75, and 100 percent of a maximum voluntary contraction showed significant increases in strength, but not in endurance. The group which trained with a 25 percent contraction increased significantly in endurance, but not in strength. The increased duration of contractions at percentages greater than or equal to 50 percent of a maximum voluntary contraction appeared to be due to increased strength. Hence, measuring cardiovascular endurance by the duration of a sustained voluntary isometric contraction at percentages greater than 25 percent seems unjustified.  相似文献   

19.
Abstract

The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 ± 6.1 years (mean ± s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2 – 3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 ± 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption ([Vdot]O2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55 – 75 years.  相似文献   

20.
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