The use of a dual-task paradigm to identify superior sensory organisation ability in rhythmic gymnasts

Previous study has showed superior sensory organisation ability in rhythmic gymnasts, but mostly in longitudinal data. With a cross-sectional design, this study used a dual-task paradigm to examine the above phenomenon. Fifteen female rhythmic gymnasts (15.0 ± 1.8 yr.) and matched peers (15.1 ± 2.1 yr.) were recruited. The Sensory Organization Test (SOT) was administered with a concurrent lower-demand (serial subtraction of three, serving as the baseline) or higher-demand (serial subtraction of seven, serving as the dual-task) arithmetic task. The results showed no main effect of group, but a group by level of arithmetic task (P = 0.001) interaction effect on SOT equilibrium score. The higher-demand task facilitated balance performance in the gymnasts, but it impeded performance in the controls, with the differences more pronounced in challenging SOT conditions. With the higher-demand task, the gymnasts adopted a sensory strategy with a higher visual ratio but a smaller somatosensory ratio compared to the controls. Better visual utilisation of sensory organisation ability was apparent in gymnasts, but only when the SOT test was performed with a higher-demand secondary task. We have demonstrated the efficacy of using the dual-task paradigm to identify the superior sensory organisation ability of adolescent rhythmic gymnasts.     

体操运动员平衡控制的感觉相互作用

本研究采用动静态平衡仪对20名体操运动员进行姿势平衡中的感觉相互作用的评估。结果发现:在不同的试验条件下,三个感觉系统对维持平衡的作用不同,体操运动员在维持平衡的过程中前庭功能和视觉都起主要作用;平衡中枢对感觉信息具有复杂的整合调节作用;运动员所应用的感觉信息和取得平衡的策略有较大的个体差异。结论:体操运动员在进行平衡能力的专项练习时,应重视视觉和前庭功能的训练。     

The influence of a hurdle target point on the kinematics of the handspring vault approach run during training

ABSTRACT

The aim of this study was to investigate if a visible target for the hurdle take-off would influence the onset of visual regulation and hurdle kinematics during the approach run. Ten elite male gymnasts (age 23.4 ± 4.9 years, height 1.68 ± 0.06 m, mass 63.3 ± 6.2 kg) performed six handspring vaults with a full approach run under two controlled conditions: (a) with a 5-cm white tape on the runway marking the last touchdown of the approach run and the commencement of the hurdle (tape condition—T) and (b) under the standard vaulting regulations (non-tape condition—NT). Spatiotemporal data of the approach run and the hurdle were collected by four stationary and one panning cameras (sampling rate 300 fps). Eight out of 10 gymnasts commenced regulation earlier under T than under NT. Under T condition, horizontal velocity (Vx _to = 9.06 ± 0.41 m/s) and vertical velocity (V _to = 9.35 ± 0.37 m/s) was significantly faster than under NT condition (Vx _to = 8.85 ± 0.49 m/s; V _to = 9.11 ± 0.47 m/s). Introducing a target for the hurdle facilitates an early onset of step regulation and significantly improves the kinematics of the hurdle.     

Relationship of performance on the sensory organization test to landing characteristics

Jump landing tasks have been used to assess landing characteristics and require significant sensorimotor feedback to maintain functional joint stability (FJS) throughout the task. Postural stability (PS) also requires significant sensorimotor feedback and control and would seemingly involve similar sensory feedback pathways. However, previous literature clarifying the relationship between these two processes, maintaining FJS and PS, is limited. 80 Special Tactics Operators. PS was assessed using the Sensory Organization Test (SOT). SOT variables included: Composite, Somatosensory, Visual, Vestibular, and Preference scores. Landing characteristics were assessed using motion analysis during a double-legged (DLSJ) and single-legged (SLSJ) stop jump task. Pearson’s correlation coefficients were calculated to assess the relationship between SOT scores and landing characteristics (α < .05). For the DLSJ, significant correlations were found between: Composite and peak posterior ground reaction forces (?.257), Vestibular and peak knee abduction moment (?.237), and Preference and initial contact hip flexion (?.297), peak hip flexion (?.249). For the SLSJ, significant correlations were found between: Somatosensory and peak vertical ground reaction forces (?.246); Preference and initial contact hip flexion (?.295), peak hip flexion (?.262). The results indicate that the SOT may not be a sensitive enough tool to assess sensorimotor control in a healthy, athletic population.     

Visual and postural control of an arbitrary posture: The handstand

Abstract

The aim of this study was to increase our understanding of postural regulation by analysing an arbitrary posture – the handstand. We assessed the relative influence of peripheral vision and central visual anchoring on the postural balance of gymnasts in the inverted-stand posture. Displacements of the centre of pressure, the angles between the body segments, and the gymnast's height in the handstand were analysed. Postural regulation in the handstand appeared to be organized according to a system similar to that in erect posture, with three articular levels suggesting the existence of a typical organization of human posture. Moreover, both intra-modal (central and peripheral vision) and inter-modal sensory systems (vision and other balance systems) contributed to the postural regulation. The results are interpreted in terms of an ecological approach to posture in which postural regulation can be considered as an emergent phenomenon.     

Centre of pressure correlates with pyramid performance in acrobatic gymnastics

Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance.     

Kinematic adaptations in sprint acceleration performances without and with the constraint of holding a field hockey stick

The aim of this study was to investigate the technique adaptations made when performing sprint-based tasks without (free condition) and with (constrained condition) the constraints of carrying a field hockey stick. Three free and three constrained maximal sprint accelerations were performed by 18 experienced university male field hockey players (age = 20 ± 1 years, body mass = 73.3 ± 7.1 kg, and stature = 1.78 ± 0.05 m). An automatic motion analysis system tracked sagittal plane active marker locations (200 Hz). M sprint velocity during the 18–22 m (free: 8.03 ± 0.43 m/s; constrained: 7.93 ± 0.36 m/s) interval was significantly (p = 0.03) different between free and constrained conditions. While the M stride length and stride frequency was similar between free and constrained conditions in the 2–13 m capture volume, the free condition elicited a 0.10 m/s faster (p = 0.03) stride velocity. Further significant differences were found between free and constrained kinematic profiles (p ≤ 0.05) for the hip angular velocity at touchdown during the 2–12 m interval of the sprints and in the overall sprint technique coordination between free and constrained conditions. Performance and technique adaptations indicated that sprint-training protocols for field sports should integrate specific equipment constraints to ensure explicit replication of the mechanical demands of the skills underpinning superior performance.     

The effect of heavy resistance exercise on repeated sprint performance in youth athletes

This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.     

Modelling training response in elite female gymnasts and optimal strategies of overload training and taper

Abstract

The aim of the study is the modelling of training responses with a variable dose-response model in a sport discipline that requires highly complex coordination. We propose a method to optimise the training programme plan using the potential maximal performance gain associated with overload and tapering periods. Data from five female elite gymnasts were collected over a 3-month training period. The relationship between training amounts and performance was then assessed with a non-linear model. The optimal magnitude of training load reduction and its duration were investigated with and without an overload period using simulation procedures based on individual responses to training. The correlation between actual and modelled performances was significant (R ² = 0.81 ± 0.02, P < 0.01). The standard error was 2.7%. Simulations revealed that taper preceded by an overload period allows a higher performance to be achieved compared to an absence of overload period (106.3 ± 0.3% vs. 105.1 ± 0.3%). With respect to the pre-taper load, the model predicts that optimal load reductions during taper were 48.4 ± 0.7% and 42.5 ± 1.0% for overloading and non-overloading strategies, respectively. Moreover, optimal durations of the taper period were 34 ± 0.5 days and 22 ± 0.5 days for overloading and non-overloading strategies, respectively. In conclusion, the study showed that the variable dose-response model describes precisely the training response in gymnasts.     

Balance and proprioception responses to FIFA 11+ in amateur futsal players: Short and long-term effects

ABSTRACT

Background: The FIFA 11+ has shown positive effects on balance and proprioception parameters in football players. As there have been very few research studies involving futsal, we examined the short and long term effects of the FIFA 11+ on static and dynamic balance, as well as proprioception in male amateur futsal players.

Methods: Seventy-one male futsal players were randomized to two groups (FIFA 11+: n = 37, age: 27.33 ± 4.33 years; Control: n = 34, age: 25.55 ± 4.65 years). Intervention lasted 10 weeks, 2 sessions per week, succeeded by a 10-week follow-up period. For balance testing, we assessed the single-legged postural sway with a force platform (static balance) and the Y balance test (dynamic balance). Proprioception was assessed with active joint position sense testing.

Results: Complete pre-post intervention and follow-up tests were available for 61 players. The FIFA 11+ group showed higher training exposure and lower body mass index and body weight. After adjustment for baseline differences, no significant differences between groups were observed in the pre-post changes for centre of pressure measures, Y-balance and proprioception parameters both at short and long-term.

Conclusions: Performing FIFA 11+ for 10 weeks did not improve static and dynamic balance as well as proprioception in amateur futsal players.     

A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties

It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (M ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional (3D) trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60–67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties.     

The appropriateness of training exposures for match-play preparation in adolescent schoolboy and academy rugby union players

The aim of this study was to compare the physical and movement demands between training and match-play in schoolboy and academy adolescent rugby union (RU) players. Sixty-one adolescent male RU players (mean ± SD; age 17.0 ± 0.7 years) were recruited from four teams representing school and regional academy standards. Players were categorised into four groups based on playing standard and position: schoolboy forwards (n = 15), schoolboy backs (n = 15), academy forwards (n = 16) and academy backs (n = 15). Global positioning system and accelerometry measures were obtained from training and match-play to assess within-group differences between conditions. Maximum data were analysed from 79 match files across 8 matches (1.3 ± 0.5 matches per participant) and 152 training files across 15 training sessions (2.5 ± 0.5 training sessions per participant). Schoolboy forwards were underprepared for low-intensity activities experienced during match-play, with schoolboy backs underprepared for all movement demands. Academy forwards were exposed to similar physical demands in training to matches, with academy backs similar to or exceeding values for all measured variables. Schoolboy players were underprepared for many key, position-specific aspects of match-play, which could place them at greater risk of injury and hinder performance, unlike academy players who were better prepared.     

The effects of a high-intensity free-weight back-squat exercise protocol on postural stability in resistance-trained males

The purpose of this study was to investigate the effects of a high-intensity free-weight back-squat exercise on postural stability characteristics in resistance-trained males. Eighteen college-aged (mean ± SD: age = 22.9 ± 2.9 years; height = 175.8 ± 6.4 cm; mass = 86.3 ± 9.3 kg), resistance-trained males performed postural stability testing before and after completing five sets of eight repetitions of back-squat exercises at 80% of one-repetition maximum. A commercial balance testing device was used to assess sway index at pre- and at 0, 5, 10, 15 and 20 min post-exercise. Each balance assessment consisted of four, 20-s static stance conditions: eyes-open firm surface, eyes-closed firm surface, eyes-open soft surface and eyes-closed soft surface. Sway index was greater (P = 0.001–0.020) at Post 0 than at all other time points. No differences (P > 0.05) were observed between any other time phases. Sway index was greater (P < 0.001) for eyes-closed soft surface than all other conditions. These findings revealed sway index for all conditions significantly increased following completion of the back-squat; however, sway index recovered within 5 min of exercise. Higher sway index values as a result of neuromuscular fatigue induced by a back-squat exercise may have performance and injury risk consequences to subsequent activities that rely on postural stability. However, these findings suggest balance impairments may recover in ~5 min following high-intensity lower body resistance exercise.     

The addition of whey protein to a carbohydrate–electrolyte drink does not influence post-exercise rehydration

The addition of whey protein to a carbohydrate–electrolyte drink has been shown to enhance post-exercise rehydration when a volume below that recommended for full fluid balance restoration is provided. We investigated if this held true when volumes sufficient to restore fluid balance were consumed and if differences might be explained by changes in plasma albumin content. Sixteen participants lost ~1.9% of their pre-exercise body mass by cycling in the heat and rehydrated with 150% of body mass lost with either a 60 g · L^?1 carbohydrate drink (CHO) or a 60 g · L^?1 carbohydrate, 20 g · L^?1 whey protein isolate drink (CHO-P). Urine and blood samples were collected pre-exercise, post-exercise, post-rehydration and every hour for 4 h post-rehydration. There was no difference between trials for total urine production (CHO 1057 ± 319 mL; CHO-P 970 ± 334 mL; P = 0.209), drink retention (CHO 51 ± 12%; CHO-P 55 ± 15%; P = 0.195) or net fluid balance (CHO ?393 ± 272 mL; CHO-P ?307 ± 331 mL; P = 0.284). Plasma albumin content relative to pre-exercise was increased from 2 to 4 h during CHO-P only. These results demonstrate that the addition of whey protein isolate to a carbohydrate–electrolyte drink neither enhances nor inhibits rehydration. Therefore, where post-exercise protein ingestion might benefit recovery, this can be consumed without effecting rehydration.     

Knee joint position sense of roller hockey players: a comparative study

This study aimed to compare knee joint position sense of roller hockey players with an age-matched group of non-athletes. Forty-three male participants voluntarily participated in this cross-sectional study: 21 roller hockey players (mean age: 23.2 ± 4.2 years old, mean weight: 81.8 ± 9.8 kg, mean height: 180.5 ± 4.1 cm) and 22 age-matched non-athletes (mean age: 23.7 ± 3.9 years old, mean weight: 85.0 ± 6.2 kg, mean height: 181.5 ± 5.0 cm). Knee joint position sense of the dominant limb was evaluated using a technique of open-kinetic chain and active knee positioning. Joint position sense was reported using absolute, relative and variable angular errors. The main results indicated that the group of roller hockey players showed significantly lower absolute (2.4 ± 1.2º vs. 6.5 ± 3.2º, p ≤ 0.001) and relative (1.7 ± 2.1º vs. 5.8 ± 4.4º, p ≤ 0.001) angular errors in comparison with the non-athletes group. In conclusion, the results from this present study suggest that proprioceptive acuity, assessed by measuring joint position sense, is increased in roller hockey players. The enhanced proprioception of the roller hockey players could contribute to injury prevention and improved performance during sporting activities.     

Control of locomotion in expert gymnasts in the absence of vision

The main aim of this study was to determine how gymnasts are affected by the removal of vision when executing simple moves. A secondary aim was to establish whether crucial sensory cues exist for blindfolded gymnasts. Eight expert gymnasts were asked to maintain a straight displacement during three types of blindfolded locomotion: walking, steering a wheelchair and verbally ordering a second person pushing their wheelchair. In the first two conditions,active displacement made proprioceptive cues available to update the body trajectory. In the last condition, however, proprioceptive cues were greatly reduced, since the gymnasts displaced passively. The performance of the gymnasts was compared to that of eight experts in other non-gymnastic sports (control group). The results showed that the participants veered in all conditions. However, except in the verbal condition, the gymnasts departed less from linearity than the controls. We conclude that: (1) even for a simple motor task, gymnasts' performance is altered by eliminating vision; (2) compared with other sportsmen and women, gymnasts are better able to deal with the absence of vision when proprioceptive cues are available. These findings suggest two possible explanations: (1) gymnasts are more able to ‘pick up' crucial information and (2) a gymnast's proprioceptive system is more sensitive.     

Coordination as a function of skill level in the gymnastics longswing

The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination.     

The influence of 2 weeks of low-volume high-intensity interval training on health outcomes in adolescent boys

Abstract

The present study aimed to establish whether 2 weeks of high-intensity interval training would have a beneficial effect on aerobic fitness, fat oxidation, blood pressure and body mass index (BMI) in healthy adolescent boys. Ten adolescent boys (15.1 ± 0.3 years, 1.3 ± 0.2 years post-estimated peak height velocity) completed six sessions of Wingate-style high-intensity interval training over a 2-week period. The first session consisted of four sprints with training progressed to seven sprints in the final session. High-intensity interval training had a beneficial effect on maximal O₂ uptake (mean change, ±90% confidence intervals: 0.19 L · min^?1, ±0.19, respectively), on the O₂ uptake at the gas exchange threshold (0.09 L · min^?1, ±0.13) and on the O₂ cost of sub-maximal exercise (–0.04 L · min^?1, ±0.04). A beneficial effect on the contribution of lipid (0.06 g · min^?1, ±0.06) and carbohydrate (–0.23 g · min^?1, ±0.14) oxidation was observed during sub-maximal exercise, but not for the maximal rate of fat oxidation (0.04 g · min^?1, ±0.08). Systolic blood pressure (1 mmHg, ±4) and BMI (0.1 kg · m², ±0.1) were not altered following training. These data demonstrate that meaningful changes in health outcomes are possible in healthy adolescent boys after just six sessions of high-intensity interval training over a 2-week period.     

艺术体操运动员上肢本体感觉能力分析

运用艺术体操圈器械对不同训练程度者及不同级别的运动员进行测试,发现有训练者与无训练者之间的抛接控制能力有着明显的差异;不同训练水平的运动员对于抛接控制能力也具有一定的差异性,训练水平越高,准确性越高;本体感觉能力具有个体差异性,其既受后天运动训练的影响作用,也受到个人先天因素的作用制约;艺术体操运动员上肢本体感觉能力的强弱,可以作为艺术体操运动员的选材与能力评定的参考指标。为今后选拔和训练艺术体操运动员提供科学准确的参考依据。