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1.
Abstract

We investigated balance in 33 competitive dancers (17 females, 16 males) and 22 controls (17 females, 5 males) (age 16–27 years) on a force plate in two conditions: single task (quiet stance) and dual task (with a concurrent mental task). Balance was evaluated using centre-of-pressure shift (sway) variability, mean speed, frequency, and sample entropy. The effect of the dual task in the medio-lateral plane was comparable in both groups, decreasing sway variability (P < 0.05) and increasing mean speed (P < 0.001), frequency, and sample entropy (P < 0.001), showing that the participants effectively increased the level of automaticity. In the antero-posterior plane, the dual task also increased sway frequency and sample entropy (P < 0.01) in dancers without affecting their standing performance. In contrast, postural control in non-dancers was vulnerable to reduced cognitive investment, which adversely interfered with baseline performance. There were very high correlations between sway sample entropy and frequency in each group, plane, and task (r = 0.92–0.98, P < 0.001), indicating that both parameters may measure the same characteristic of postural control and that higher sway frequency may play an important role in protecting stability in dual tasking. The postural control of dancers and non-dancers appears to be similar, although dancing seems to facilitate the increased level of automatic control in the antero-posterior plane.  相似文献   

2.
The influence of a 12-week-proprioceptive training on functional ankle stability was investigated in young speed skaters. Twenty-eight speed skaters were randomly divided into an intervention (n = 14) and into a control group (n = 14). A 15-min circle training was performed 5 times per week over a 12-week period. Measurements were taken prior to the training, after 6 and 12 weeks of training. Kinaesthesia was evaluated with the Isomed2000 in all movements of the ankle joint. Dynamic balance was tested with the Biodex Stability System at the stable level 8 and at the unstable level 2, measuring the overall stability index, the anterior/posterior and the medial/lateral scores. Static single-leg stance was evaluated using the Kistler force platform. Kinaesthesia of the intervention group improved significantly for plantarflexion of the right foot (P = 0.001) after 12 weeks. Dynamic balance showed significant differences in the intervention group after 12 weeks in comparison with the first measurement for each foot in the overall stability index, the anterior/posterior and the medial/lateral scores (P ≤ 0.017, respectively) at the unstable level 2. Functional ankle stability improved in terms of dynamic balance after 12 weeks of proprioceptive training. Therefore, inclusion of proprioceptive exercises in the daily training programme is recommended for young speed skaters.  相似文献   

3.
Abstract

The aim of the present study was to determine whether changing stance width would result in a corresponding change in postural and/or pistol stability. Twelve national-standard male air pistol shooters performed 10 shots each at five stance widths (30 cm, 45 cm, 60 cm, 75 cm, and 90 cm). Postural stability was determined by measuring centre-of-pressure changes with a dual force-platform system. Shooting mechanics measures were determined by a NOPTEL ST-2000 optoelectronic training system. Medial-lateral centre-of-pressure excursion (F 4,44 = 7.17, P < 0.001, effect size = 0.99) and speed (F 4,44 = 77.03, P < 0.001, effect size = 3.88) were reduced as stance width decreased. Centre of gravity fine (the percentage of time held within an area the size of the ten-ring) improved during narrower stance widths (F 4,32 = 12.49, P < 0.001, effect size = 0.71). Our findings suggest that stance width affects postural and pistol stability in national-standard air pistol athletes. Moreover, the current method of suggesting a wider stance to improve shooting performance should be reconsidered and perhaps air-pistol shooters should use a 30-cm stance width to improve postural stability and shooting performance.  相似文献   

4.
The purpose of the study was to investigate the effects of two weeks of self-control strength training on maximum cardiovascular exercise performance. Forty-one participants completed a cognitive self-control depletion task (Stroop task) followed by a maximal graded cycling test and were randomized to training (maximal endurance contractions of spring handgrip trainers, twice daily) or no-treatment control groups. At follow-up (2 weeks), half of each group completed either a time-matched or trial-matched Stroop task followed by another maximal graded cycling test. Results showed a significant 2-way (training X time) interaction (P < 0.001), and a trend for the 3-way (training X time X cognitive task) interaction (P = 0.07). Decomposition of the interactions revealed that across sessions cycling performance increased in both training groups, did not change in the trial-matched cognitive task control group, and declined in the time-matched control group. We conclude that isometric handgrip training leads to self-control strength adaptations that enhance maximal cardiovascular exercise performance or tolerance of exercise at maximal levels of effort.  相似文献   

5.
Cognition is important in many sports, for example, making split-second-decisions under pressure, or memorising complex movement sequences. The dual-task (DT) paradigm is an ecologically valid approach for the assessment of cognitive function in conjunction with motor demands. This study aimed to determine the impact of impaired intelligence on DT performance. The motor task required balancing on one leg on a beam, and the cognitive task was a multiple-object-tracking (MOT) task assessing dynamic visual-search capacity. The sample included 206 well-trained athletes with and without intellectual impairment (II), matched for sport, age and training volume (140 males, 66 females, M age = 23.2 ± 4.1 years, M training experience = 12.3 ± 5.7 years). In the single-task condition, II-athletes showed reduced balance control (F = 55.9, P < .001, η2 = .23) and reduced MOT (F = 86.3, P < .001, η2 = .32) compared to the control group. A mixed-model ANCOVA revealed significant differences in DT performance for the balance and the MOT task between both groups. The DT costs were significantly larger for the II-athletes (?8.28% versus ?1.34% for MOT and ?33.13% versus ?12.89% for balance). The assessment of MOT in a DT paradigm provided insight in how impaired intelligence constrains the ability of II-athletes to successfully perform at the highest levels in the complex and dynamical sport-environment.  相似文献   

6.
The aim of this investigation is to assess the effectiveness of a 6-week balance training (BT) protocol, integrated in regular training sessions, on postural sway of young female volleyball players (n = 26, age 13.0 ± 0.2 years) divided into two groups (intervention and control; 13 per group). Trials were performed for bipedal and unipedal stance conditions before and after the BT protocol, using a pressure platform to collect center-of-pressure (COP) time series that were processed to calculate sway area, COP path length, and maximum displacement range in anteroposterior and mediolateral directions. The intervention group exhibited smaller sway areas in eyes closed conditions (intervention = 42.76 mm2, control = 67.60 mm2; p < 0.05) and Romberg quotients (intervention = 1.11 mm, control = 1.82 mm) in bipedal stance, while all the other parameters were unaffected. BT also reduced sway area (intervention = 122.70 mm2, control = 187.18 mm2) and anteroposterior COP displacements (intervention = 20.18 mm, control = 22.38 mm) of the non-dominant limb for single-leg stance. No significant change was found for the dominant limb. Although it is possible to hypothesize a beneficial effect of BT on young athletes, further investigations are required to clarify its actual effect on balance performance with respect to normal volleyball training.  相似文献   

7.
This study investigated the influence of external load training (ELT) on static and dynamic balance. Nineteen females stratified into two groups (ELT = 9, control = 10) completed three testing sessions over 6 weeks. The ELT group wore weighted vests (WV) of ~8% body mass for 32 h/week during daily living and three training sessions/week for 3 weeks. Following completion of ELT, a 3 week detraining (DET) phase was completed. Bilateral and unilateral static balance were assessed with eyes open and closed. Dynamic balance was assessed using the star excursion balance test (SEBT). Static and dynamic balance variables were analysed using a 2 (group) x 3 (time) between participants repeated measures ANOVA (p < 0.05). Results revealed significant reductions in average centre of pressure (COP) velocity in the control group on the non-dominant limb with eyes closed, and significantly greater reach distances in the ELT group on the SEBT for the posteromedial and medial directions on the dominant limb (p < 0.05). These findings suggest the ELT group did not significantly improve their balance in comparison to the control group. However, future research should further examine this unique, supplemental training method and the impact on balance performance.  相似文献   

8.
This study analysed the effects of bilateral and non-dominant practice on novice practitioners’ lateral preference for judo skills in a combat context (i.e., randori). Thirty sports sciences students (22 men and 8 women; mean age 19 ± 1 years) with right hand, foot, and counterclockwise rotation preferences were divided into 3 groups: bilateral (BG; n = 8), non-dominant (NDG; n = 11), and control (CG; n = 11). Participants received 8 weeks of training at a rate of 3 days per week. The NDG was trained to perform judo skills exclusive with their non-dominant side, while the BG performed every task symmetrically. Before and after training, participants were recorded during two 3-min randoris to obtain the percentage of their engagement in dominant side actions. Pretest percentages were 73.1 ± 19.9%, 77.8 ± 18.8%, and 68.9 ± 27.2% for BG, NDG, and CG, respectively. Post-test values were 75.0 ± 15.6%, 23.3 ± 27.9%, and 72.2.9 ± 20.4%, respectively. Significant differences were observed between NDG and each of the other groups after the training. Changes from pretest were only significant for NDG (P = 0.003). These results suggest that lateral preference among novice judo practitioners during randori can be modulated by the type of practice.  相似文献   

9.
Combining dynamic postural control assessments and cognitive tasks may give clinicians a more accurate indication of postural control under sport-like conditions compared to single-task assessments. We examined postural control, cognitive and squatting performance of healthy individuals during static and dynamic postural control assessments in single- and dual-task paradigms. Thirty participants (female = 22, male = 8; age = 20.8 ± 1.6 years, height = 157.9 ± 13.0 cm, mass = 67.8 ± 20.6 kg) completed single-leg stance and single-leg squat assessments on a force plate individually (single-task) and concurrently (dual-task) with two cognitive assessments, a modified Stroop test and the Brooks Spatial Memory Test. Outcomes included centre of pressure speed, 95% confidence ellipse, squat depth and speed and cognitive test measures (percentage of correct answers and reaction time). Postural control performance varied between postural control assessments and testing paradigms. Participants did not squat as deep and squatted slower (P < 0.001) during dual-task paradigms (≤12.69 ± 3.4 cm squat depth, ≤16.20 ± 4.6 cm · s?1 squat speed) compared to single-task paradigms (14.57 ± 3.6 cm squat depth, 19.65 ± 5.5 cm · s?1 squat speed). The percentage of correct answers did not change across testing conditions, but Stroop reaction time (725.81 ± 59.2 ms; F2,58 = 7.725, P = 0.001) was slowest during single-leg squats compared to baseline (691.64 ± 80.1 ms; P = 0.038) and single-task paradigms (681.33 ± 51.5 ms; P < 0.001). Dynamic dual-task assessments may be more challenging to the postural control system and may better represent postural control performance during dynamic activities.  相似文献   

10.
The purpose of this study was to examine the effect of a 12-week resistance training programme on fat-free mass (FFM), muscle cross-sectional area, muscular strength and muscle quality in women who underwent Roux-en-Y gastric bypass surgery. Participants were 16 women (mean age = 44.9 ± 10.2 years) from bariatric surgical groups who were randomly assigned into either a control or an intervention group. Air displacement plethysmography measured FFM and magnetic resonance imaging measured quadriceps muscle cross-sectional area and whole thigh muscle cross-sectional area. Muscular strength and quality was assessed using an estimated 1-Repetition Maximum assessment. All measurements were collected twice, at baseline and at a 12-week follow-up. There were significantly greater improvements in leg press strength (mean differences = 55.4%, P < 0.001, Cohen’s d = 2.4), leg extension strength (mean differences = 18.0%, P = 0.014, Cohen’s d = 0.86) and leg press muscle quality (mean differences = 54.5%, P < 0.001, Cohen’s d = 1.9) in the intervention group compared to the control group following the resistance training programme. The resistance training intervention significantly improved muscular strength and quality; however, it did not illicit changes in FFM or muscle cross-sectional area in women who underwent Roux-en-Y gastric bypass surgery.  相似文献   

11.
The aim of this study was to examine lower limb joint kinetics during the block and first stance phases in athletic sprinting. Ten male sprinters (100 m PB, 10.50 ± 0.27 s) performed maximal sprint starts from blocks. External force (1000 Hz) and three-dimensional kinematics (250 Hz) were recorded in both the block (utilising instrumented starting blocks) and subsequent first stance phases. Ankle, knee and hip resultant joint moment, power and work were calculated at the rear and front leg during the block phase and during first stance using inverse dynamics. Significantly (P < 0.05) greater peak moment, power and work were evident at the knee joint in the front block and during stance compared with the rear block. Ankle joint kinetic data significantly increased during stance compared with the front and rear block. The hip joint dominated leg extensor energy generation in the block phase (rear leg, 61 ± 10%; front leg, 64 ± 8%) but significantly reduced during stance (32 ± 9%), where the ankle contributed most (42 ± 6%). The current study provides novel insight into sprint start biomechanics and the contribution of the lower limb joints towards leg extensor energy generation.  相似文献   

12.
The current study compared changes in neuromuscular control between slackline training and the stabilization training elements of the FIFA 11+ programme. Twenty-five students in 2 groups performed a 12-unit training programme. The slackline training group (n?=?13) exclusively trained with a slackline. The stabilization training group (n?=?12) practised exercises as described in the second part of the FIFA 11+ programme. Improvements in balance were assessed using three tests for dynamic, quasi-static, and perturbed postural control: the star excursion balance test (SEBT), the closed-eye single-leg stance, and the MFT S3-Check. Both groups significantly improved the stability and sensorimotor index of the MFT S3-Check (p?<?.001), their range on the SEBT (p?<?.001), and the duration of closed-eye single-leg stance (p?<?.001). The group?×?training interaction was significant for the MFT S3-Check (stability index: p?=?.042; sensorimotor index: p?=?.004) and the SEBT (dominant leg: p?=?.003; averaged both legs: p?=?.016), with the slackline training group showing a larger training effect than the stabilization training group. The results of the present study suggest that slackline training offers similar – or better – improvements in neuromuscular control as the FIFA 11+ warm-up programme. If compliance with the FIFA 11+ programme is declining, then slacklining might offer an alternative approach to reach the training goals of improved sensorimotor control.  相似文献   

13.
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14.
目的:从生物力学角度探究声音反馈训练(teaching with acoustical guidance,TAGteachTM)和传统训练方法对高尔夫初学者击球效果和挥杆动作的影响。方法:21名无高尔夫训练基础的大学生受试者随机分为声音反馈训练组(clicker training group,CG,n=11)和传统训练组(traditional training group,TG,n=10),由一名韩国职业高尔夫教练员进行5周的高尔夫挥杆动作教学训练,使用7号铁杆。训练后,对受试进行挥杆动作生物力学测试,对比两组受试者的击球效果和挥杆动作。结果:5周声音反馈训练后,CG杆速、球速、杆面角度、击球距离等击球表现指标显著优于TG(P<0.01)。挥杆动作方面,CG从上杆阶段到随挥初期挥杆时间显著小于TG(P<0.05),骨盆转动速度显著大于TG(P<0.05);CG骨盆转动角度和COM-COP倾角的标准化角加速度变化率显著小于TG(P<0.05)。结论:声音反馈是一种有效的训练辅助手段,可提升高尔夫初学者的挥杆练习效果。  相似文献   

15.
The aim of this study was to assess the effect of a unilateral anterior cruciate ligament reconstruction (ACLR) on maximum voluntary contraction (MVC) and explosive strength of both the involved limb and the uninvolved limb. Nineteen male athletes completed a standard isometric testing protocol 4 months post-ACLR, while 16 healthy participants served as a control group (CG). The explosive strength of the knee extensors and flexors was assessed as RFD obtained from the slope of the force–time curves over various time intervals. Both muscle groups of the involved limb had significantly lower MVC compared to the uninvolved. The involved limb also had significantly lower RFD in the late phase of contraction (140–250 ms) for both knee extensors and flexors (P < 0.05). There was no difference in MVC between the uninvolved limb and the CG. However, RFD of the uninvolved limb was lower compared to CG for both knee extensors (0–180 ms; P < 0.01) and flexors (0–150 ms; P < 0.05). ACLR leads to lower MVC and explosive strength of the involved limb. As a consequence of potential crossover (presumably neural-mediated) effects, explosive strength deficits could be bilateral, particularly in the early phase of the contraction (<100 ms).  相似文献   

16.
This study aimed to establish the reliability of a novel netball task using a single-leg horizontal jump (SLHJ). Twenty-five females 18–39 years performed SLHJs for maximal displacement and ground-reaction forces. Participants completed two trials for each leg on two occasions separated by 6 weeks of pre-season netball training. Paired sample t tests highlighted no significant differences within trials for either limb. Significant (p ≤ .05) changes are reported for displacement, and dominant and nondominant X and Y forces, after 6-week netball training. SLHJ displacement showed excellent within-session reliability at baseline for dominant (intraclass correlation coefficient (ICC(2,1)) = 0.922, 95% confidence interval (CI) 0.826–0.966) and nondominant (ICC(2,1) = 0.925; 95% CI 0.832–0.967) landings. At 6 weeks, within-session reliability remained excellent for dominant (ICC(2,1) = 0.967, 95% CI 0.926–0.985) and nondominant ICC 0.968 (95% CI 0.929–0.986) landings. The reliability of the single-leg horizontal jump task for netball remained strong after 6 weeks of netball training.  相似文献   

17.
Purpose: This study aimed to investigate the effects of water-based aerobic training on the lipid profile and lipoprotein lipase (LPL) levels in premenopausal women with dyslipidemia. Method: Forty women were randomly assigned to: aquatic training (WA; n = 20) or a control group (CG; n = 20). The WA group underwent 12 weeks of water-based interval aerobic training twice a week at intensities ranging from 9 to 15 on the Borg Scale of Perceived Exertion. Total cholesterol (TC), triglycerides (TG), high- (HDL) and low- (LDL) density lipoprotein, TC/HDL ratio, LPL levels, and peak oxygen consumption (VO2peak) were evaluated before and after 12 weeks in both groups. Results: The WA group elicited decreases in TC (9%; effect size [ES] = 0.69; 95% CI [0.05, 1.33]), LDL (16%; ES = 0.78; 95% CI [0.13, 1.42]), and the TC/HDL ratio (17%; ES = 1.13; 95% CI [0.46, 1.79]), as well as increases in VO2peak (10%; ES = 0.64; 95% CI [0.002, 1.27]) and HDL (10%; ES = 0.28; 95% CI [?0.35. 0.90]), without significant changes in TG (ES = 0.16; 95% CI [?0.46, 1.79]) and LPL (ES = 0.36; 95% CI [?0.27, 0.98]) levels. In the CG, no statistically significant changes in any of these variables were found (TC, ES = 0.19, 95% CI [?0.43, 0.82]; LDL, ES = 0.22, 95% CI [?0.40, 0.85]; HDL, ES = 0.05, 95% CI [?0.57, 0.67]; TG, ES = 0.09, 95% CI [?0.53, 0.71]; TC/HDL ratio, ES = 0.20, 95% CI [?0.42, 0.82]; LPL, ES = 0.02, 95% CI [?0.60, 0.64]; VO2peak, ES = 0.20, 95% CI [?0.42, 0.82]). Conclusion: Water-based interval aerobic training positively affected the lipid profile in premenopausal dyslipidemic women.  相似文献   

18.
This study compared the functional and neural effects of two strength training programmes differing in set configuration. Thirteen participants performed 10 sessions, over a period of 5 weeks, of unilateral leg extensions with different set configurations but with identical work-to-rest ratios for each limb: a traditional configuration (4 sets of 8 repetitions, 10RM load, 3-min pause between sets) and an inter-repetition rest configuration (32 repetitions, 10RM load, 17.4 s of rest between each repetition). Mean propulsive velocity of the traditional sessions was lower than for inter-repetition rest sessions (0.48 ± 0.06 vs. 0.54 ± 0.06 m · s?1; P < 0.001), while perceived exertion was higher (8.3 ± 0.9 and 6.56 ± 1.6 for traditional training and IRT; P = 0.002). One repetition maximum (RM), work with 10RM load, maximum mean propulsive power, maximum voluntary contraction and time to failure with 50% of maximum isometric force improved similarly in both legs (time effect, P < 0.001; effect size range, 0.451–1.190). Time and set configuration did not show significant main effects or interactions for cortical adaptations (motor-evoked potentials, short-interval intracortical inhibition, intracortical facilitation). There were no significant correlations between changes in cortical and peripheral neural adaptations and strength improvement. In conclusion, inter-repetition rest configuration was as effective as traditional training in improving muscle performance.  相似文献   

19.
运用摄影测量法和Novel Pedar-X足底压力测试系统采集了16名太极拳练习者在太极拳运动和正常步行中足底压力和运动影像信息,并对两种运动方式的单脚支撑姿势持续时间指标进行对比分析。研究表明:与正常步行相比,在太极拳运动中单脚支撑姿势总的持续时间所占比例(标准化值)较少(P<0.05);单次单脚支撑姿势平均持续时间较长(P<0.01);认为太极拳运动可以提高人体单脚平衡能力。另外还发现太极拳运动和正常步行中地面反作用力都在不断变化;太极拳运动中地面反作用力小于其正常步行值。  相似文献   

20.
Abstract

The effect of altering the rest period on adaptations to high-repetition resistance training is not well known. Eighteen active females were matched according to leg strength and repeated-sprint ability and randomly allocated to one of two groups. One group performed resistance training with 20-s rest intervals between sets, while the other group employed 80-s rest intervals between sets. Both groups performed the same total training volume and load. Each group trained 3 days a week for 5 weeks [15- to 20-repetition maximum (RM), 2 – 5 sets]. Repeated-sprint ability (5×6-s maximal cycle sprints), 3-RM leg press strength, and anthropometry were determined before and after each training programme. There was a greater improvement in repeated-sprint ability after training with 20-s rest intervals (12.5%) than after training with 80-s rest intervals (5.4%) (P = 0.030). In contrast, there were greater improvements in strength after training with 80-s rest intervals (45.9%) than after training with 20-s rest intervals (19.6%) (P = 0.010). There were no changes in anthropometry for either group following training. These results suggest that when training volume and load are matched, despite a smaller increase in strength, 5 weeks of training with short rest periods results in greater improvements in repeated-sprint ability than the same training with long rest periods.  相似文献   

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