Effects of balance and resistance training in children, adolescents, and seniors

Background and aims

Over the last few decades, demographic change has affected the German population in terms of a decreasing proportion of young people and an increasing proportion of elderly people. Both age groups have deficits in motor performance in common, either due to maturation and secular declines (children and adolescents) or due to biologic aging (seniors). As a consequence, deficits in postural control and muscle strength can be observed in children, adolescents, and seniors. Given these functional limitations, it is not surprising that risk of falling and, thus, medical care is particularly high in these age groups. Therefore, the objectives of this work were to investigate whether resistance or balance training have an effect on intrinsic fall risk factors (i.e., deficits in balance and strength) in children, adolescents, and seniors.

Methods

Healthy prepubertal, adolescent, and elderly subjects participated in a series of longitudinal studies. Muscle strength of the lower extremities was assessed by means of an isokinetic device and/or force plates. Postural control was determined during quiet and perturbed stance on a balance platform, during unperturbed multitask walking on a pressure sensitive walkway, as well as during perturbed walking on a treadmill. In addition, activity of lower extremity muscles was recorded.

Results

Balance training significantly improved postural sway, the ability to compensate for stance and gait perturbations, and strength performance of the lower extremities in adolescents, and seniors, however not in prepubertal children. Resistance training significantly enhanced strength performance, but not performance in biomechanic tests assessing postural control in adolescents and seniors.

Conclusion

The investigated effects of balance and resistance training on postural control and strength together with data from epidemiologic studies imply that the combination of balance and resistance training is best suited for fall prevention, because it effectively counteracts a large number of intrinsic fall risk factors.     

Field and laboratory correlates of performance in competitive cross-country mountain bikers

We designed a laboratory test with variable fixed intensities to simulate cross-country mountain biking and compared this to more commonly used laboratory tests and mountain bike performance. Eight competitive male mountain bikers participated in a cross-country race and subsequently did six performance tests: an individual outdoor time trial on the same course as the race and five laboratory tests. The laboratory tests were as follows: an incremental cycle test to fatigue to determine peak power output; a 26-min variable fixed-intensity protocol using an electronically braked ergometer followed immediately by a 1-km time trial using the cyclist's own bike on an electronically braked roller ergometer; two 52-min variable fixed-intensity protocols each followed by a 1-km time trial; and a 1-km time trial done on its own. Outdoor competition time and outdoor time trial time correlated significantly (r = 0.79, P < 0.05). Both outdoor tests correlated better with peak power output relative to body mass (both r = -0.83, P < 0.05) than absolute peak power output (outdoor competition: r = -0.65; outdoor time trial: r = -0.66; non-significant). Outdoor performance times did not correlate with the laboratory tests. We conclude that cross-country mountain biking is similar to uphill or hilly road cycling. Further research is required to design sport-specific tests to determine the remaining unexplained variance in performance.     

Noise-enhanced dynamic single leg balance in subjects with functional ankle instability

BackgroundStochastic resonance stimulation (SRS) transmits subsensory electrical Gaussian white noise into the body to enhance sensorimotor function. This therapy has improved static single leg balance in subjects with functional ankle instability. However, the effect of this stimulation on dynamic single leg balance is not known. Improvements in dynamic single leg balance with SRS may have implications for enhancing functional rehabilitation for ankle instability. Thus, the purpose of this study was to determine the effects of SRS on dynamic single leg balance in subjects with functional ankle instability.MethodsThis study was an experimental research design and data were collected in a sports medicine research laboratory. Twelve subjects with functional ankle instability (69 ± 15 kg; 173 ± 10 cm; 21 ± 2 years) reported a history of ankle sprains and instability at the ankle with physical activity. A single leg jump-landing test was used to assess dynamic balance. Subjects were required to jump between 50% and 55% of the maximal vertical jump height, land on a single leg atop a force plate, and stabilize as quickly as possible. Jump-landing tests were performed with and without SRS. Three trials were performed for each treatment condition (SRS and control). A randomized block design was used to determine test order. Anterior/posterior and medial/lateral time-to-stabilization were computed to assess dynamic balance. Lesser time indicated better stability. One-tailed paired samples t tests were used for analysis (α ≤ 0.05).ResultsSRS improved anterior/posterior time-to-stabilization (stochastic resonance = 1.32 ± 0.31 s, control = 1.74 ± 0.80 s, p = 0.03), but did not enhance medial/lateral time-to-stabilization (stochastic resonance = 1.95 ± 0.40 s, control = 1.92 ± 0.48 s, p = 0.07).ConclusionClinicians might use SRS to facilitate balance improvements with sagittal plane dynamic single leg balance exercises that patients may not be able to perform otherwise.     

论竞技网球运动体能特征

体能作为竞技能力结构中重要一环在学术界已经有广泛共识,在为了获取比赛胜利的竞技体育中的重要性可见一斑。竞技网球运动要求多种体能素质,这些体能素质集成了多种主要的变量,然而,这些重要变量的特征还未能适当的定义。尽管一般力量和柔韧性训练已经被认为对运动成绩和伤病的预防有积极的作用,但是网球运动体能的特征并不完善,甚至比较落后。本文通过对网球项目特征的相关研究,揭示了网球专项的体能特征。为网球运动训练更加合理化、科学化、构建科学的训练体系提供参考。     

过度训练综合症的预防、诊断和治疗

成功的训练不仅涉及到过负荷,同时必须避免大量过负荷练习与不充分恢复相结合。运动员可经历短期运动成绩下降。这一功能性过量训练在恢复后,可提高运动成绩。当训练和恢复之间平衡被破坏,可发生非功能性的过量训练(NFOR)。区分NFOR和过度训练综合症非常困难(OTS),取决于临床结果和排除诊断。诊断OTS的关键词是"延长性的不良适应",以及生物、神经生化和激素调节上的机制。普遍认为OTS症状比NFOR严重,如疲劳、成绩下降、情绪障碍。尽管目前没有单一的标志物可检测OTS,定期监测运动成绩、生理、生化、免疫和心理上的指标可能是最好的策略:发现不能够应对训练应激的运动员。     

How performance analysis of elite long jumping can inform representative training design through identification of key constraints on competitive behaviours

Abstract

Analysing performance in competitive environments enables identification of key constraints which shape behaviours, supporting designs of more representative training and learning environments. In this study, competitive performance of 244 elite level jumpers (male and female) was analysed to identify the impact of candidate individual, environmental and task constraints on performance outcomes. Findings suggested that key constraints shaping behaviours in long jumping were related to: individuals (e.g. particularly intended performance goals of athletes and their impact on future jump performance); performance environments (e.g. strength and direction of wind) and tasks (e.g. requirement for front foot to be behind foul line at take-off board to avoid a foul jump). Results revealed the interconnectedness of competitive performance, highlighting that each jump should not be viewed as a behaviour in isolation, but rather as part of a complex system of connected performance events which contribute to achievement of competitive outcomes. These findings highlight the potential nature of the contribution of performance analysis in competitive performance contexts. They suggest how practitioners could design better training tasks, based on key ecological constraints of competition, to provide athletes with opportunities to explore and exploit functional intentions and movement solutions high in contextual specificity.     

The role of preparatory heart rate deceleration on balance beam performance

Preparatory heart rate deceleration occurs in tasks with an external focus of attention and is often assumed to facilitate balance performance. However, its effects upon sport-related complex balance movements have not been studied. Heart rate patterns during the preparation period of an acrobatic element (flic-flac) on the balance beam were studied in 14 female gymnasts (M age 13.2 years). A significant heart rate deceleration was found in attempts with a fall in the consecutive acrobatic element, but not in attempts without a fall. These data suggest that preparatory heart rate deceleration may be detrimental to the performance of complex movements on the balance beam.     

Strength,power, and postural control in seniors: Considerations for functional adaptations and for fall prevention

Abstract

The ageing neuromuscular system is affected by structural and functional changes that lead to a general slowing down of neuromuscular performance and an increased risk of falling. As a consequence, the process of ageing results in a reduced ability to develop maximal and explosive force, as well as in deficits in static and dynamic postural control. A decrease in the number and size of type II fibres in particular accounts for the age-related decline in muscle mass (sarcopaenia) and strength performance. Multiple denervation and re-innervation processes of muscle fibres seem to be responsible for the reduced number of muscle fibres. Recently, it has been suggested that it is not the decline in motoneurons that accounts for the loss in number of muscle fibres but the disturbed potential of fibre regeneration and re-innervation. Furthermore, an age-related reduction in the number of satellite cells has also been associated with sarcopaenia. The ability to compensate for platform and gait perturbations deteriorates with ageing as reflected in longer onset latencies and inefficient postural responses. All sites within the somatosensory system are affected by ageing and therefore contribute to postural instability. However, morphological changes of muscle spindles appear primarily to be responsible for the impaired ability to compensate for balance threats in old age. Given these neuromuscular limitations in old age, it is important to apply adequate training interventions that delay or even reverse the onset of these constraints. Strength training has the potential to enhance maximal as well as explosive force production capacity. This is accomplished by neural factors, including an improved recruitment pattern, discharge rate, and synchronization of motor units. Furthermore, an increase in number of satellite cells most likely accounts for training-induced muscle hypertrophy. Recent studies have investigated the impact of balance training in old age on the ability to develop maximal and explosive force. In addition, the effects of balance training on reflex activity during gait perturbations were also examined. Increases in maximal and explosive force production capacity and an improved ability to compensate for gait perturbations were observed. It is evident from the literature that researchers are increasingly studying the effects of more specifically designed training programmes on performance in populations of older adults. Thus, in the near future, strength training could be replaced by high-velocity forms of power training and balance training by perturbation-based training programmes. It is hypothesized that this new approach is more efficient in terms of fall prevention than the traditional approach.     

提高射击运动员重大比赛中发挥能力相关问题探讨

在总结和分析多年对射击运动员科技攻关与服务成果的基础上,对运动员在重大比赛中如何提高自身的比赛能力、充分发挥训练水平的相关问题进行探讨,以帮助教练员、运动员和科研人员提高赛前训练的针对性。射击运动员动作简单明快的先进技术、合理有效的专项体能训练、系统的机能监控与合理的营养调控、中枢神经兴奋性的适度维持、以及技术、心理和生理机能的有机平衡等条件是运动员比赛中正常发挥或超水平发挥的基础和关键。     

Field and laboratory correlates of performance in competitive cross-country mountain bikers

Abstract

We designed a laboratory test with variable fixed intensities to simulate cross-country mountain biking and compared this to more commonly used laboratory tests and mountain bike performance. Eight competitive male mountain bikers participated in a cross-country race and subsequently did six performance tests: an individual outdoor time trial on the same course as the race and five laboratory tests. The laboratory tests were as follows: an incremental cycle test to fatigue to determine peak power output; a 26-min variable fixed-intensity protocol using an electronically braked ergometer followed immediately by a 1-km time trial using the cyclist's own bike on an electronically braked roller ergometer; two 52-min variable fixed-intensity protocols each followed by a 1-km time trial; and a 1-km time trial done on its own. Outdoor competition time and outdoor time trial time correlated significantly (r = 0.79, P < 0.05). Both outdoor tests correlated better with peak power output relative to body mass (both r = ?0.83, P < 0.05) than absolute peak power output (outdoor competition: r = ?0.65; outdoor time trial: r = ?0.66; non-significant). Outdoor performance times did not correlate with the laboratory tests. We conclude that cross-country mountain biking is similar to uphill or hilly road cycling. Further research is required to design sport-specific tests to determine the remaining unexplained variance in performance.     

对跆拳道运动中平衡能力的作用及训练手段的研究

跆拳道运动专顶平衡能力是指在跆拳道运动中,运动员为了提高击打效果,在即使身体处于不稳定的状态下,仍能迅速、准确、协调的控制身体姿势并完成击打动作或躲闪防守动作的能力。它是发展和完善运动技术,提高跆拳道运动员协调能力及比赛成绩的基础能力。本论文通过对平衡能力的作用及训练手段的研究,希望能使教练员和运动员更加重视平衡能力的训练,同时对有效指导教练员科学的训练起到一定的促进作用。     

The Interaction of Functional and Dysfunctional Emotions During Balance Beam Performance

The interaction between functional and dysfunctional emotions, as one of the major tenets of the Individual Zones of Optimal Functioning (IZOF) model (Hanin, 2000), was studied in a sport specific setting. Fourteen female gymnasts performed three attempts of a compulsory balance beam routine at three different heights. Heart rate and self-report of functional and dysfunctional emotions were measured during each routine. These data revealed the effectiveness of inducting emotions by manipulating height. Also, performance decreased on the most challenging condition, (i.e., the first attempt on the highest height). Moderated hierarchical regression analysis revealed a significant interaction between functional and dysfunctional emotions only when the dysfunctional emotion level was low.     

The Relationship Between Physical Activity and Thermal Protective Clothing on Functional Balance in Firefighters

We investigated the relationship between baseline physical training and the use of firefighting thermal protective clothing (TPC) with breathing apparatus on functional balance. Twenty-three male firefighters performed a functional balance test under four gear/clothing conditions. Participants were divided into groups by physical training status, and task performance was analyzed. There was an effect of equipment and training status on performance with the group reporting both aerobic and resistance training performing better than the group reporting no physical training. In conclusion, firefighters walk more slowly as a strategy to maintain balance when wearing TPC, which may be suboptimal given the emergent nature of fire suppression. This result was most prominent in the group reporting no physical training.     

浅析平衡能力对三级跳远专项能力的提高

本文采用文献资料、数据分析等方法对三级跳远的平衡能力重要性进行分析研究。结论:越是技术好成绩优异的运动员,身体躯干越稳定,使水平速度能更好的保持到最后,为创造好成绩奠定基础;要想更好的将身体素质转化到专项技术,需要空中很好的专项技术动作平衡能力,这种维持身体姿势,做出高难度专项动作的能力是三级跳远运动员必备的基本能力;三级跳远运动员躯干的前倾角度和侧倾角度对于运动员的成绩有重要影响。建议:有针对性的将训练手段往专项技术转换,能更准确有效的提高运动员专项能力的提高,进而促进专项成绩的提高;根据运动生物力学规律和运动解剖学,重点增强专项技术用力频繁的主要肌肉群,尤其是增加躯干核心肌肉群的练习;适当的静力性练习可以很好的发展运动员某个区域的绝对力量和力量耐力,但是要掌握好量和强度。     

Technical and tactical skills related to performance levels in tennis: A systematic review

The aim of this systematic review is to provide an overview of outcome measures and instruments identified in the literature for examining technical and tactical skills in tennis related to performance levels. Such instruments can be used to identify talent or the specific skill development training needs of particular players. Searches for this review were conducted using the PubMed, Web of Science, and PsycInfo databases. Out of 733 publications identified through these searches, 40 articles were considered relevant and included in this study. They were divided into three categories: (1) technical skills, (2) tactical skills and (3) integrated technical and tactical skills. There was strong evidence that technical skills (ball velocity and to a lesser extent ball accuracy) and tactical skills (decision making, anticipation, tactical knowledge and visual search strategies) differed among players according to their performance levels. However, integrated measurement of these skills is required, because winning a point largely hinges on a tactical decision to perform a particular stroke (i.e., technical execution). Therefore, future research should focus on examining the relationship between these skills and tennis performance and on the development of integrated methods for measuring these skills.     

Comment on a Preliminary Comparison of Front and Back Squat Exercises (Russell & Phillips, 1989)

Abstract

Perception of affordances research in children with developmental disabilities has only examined well practiced skills. Ten toddlers with Down syndrome and 10 with typical development walked across a GAITRite mat, with and without an obstacle. We coded the toddlers' behaviors after 1 and 3 months of walking experience when they encountered the obstacle (avoid, crawl, error, and walk successfully) and calculated gait parameters (step length, width, and velocity). Both groups actively explored their affordances. Despite similar decreases in step length and velocity when approaching the obstacle, toddlers with Down syndrome were more likely to select successful but conservative crawling strategies that minimized balance requirements and reduced risk of falling. Group differences were due to risk management rather than difficulty perceiving affordances.     

Sternal Precautions: Is It Time for Change? Precautions versus Restrictions – A Review of Literature and Recommendations for Revision

The processes that occur with normal sternal healing and potential complications related to median sternotomy are of particular interest to physical therapists. The premise of patients following sternal precautions (SP) or specific activity restrictions is the belief that avoiding certain movements will reduce risk of sternal complications. However, current research has identified that many patients remain functionally impaired long after cardiothoracic surgery. It is possible that some SP may contribute to such functional impairments. Currently, SP have several limitations including that they: (1) have no universally accepted definition, (2) are often based on anecdotal/expert opinion or at best supported by indirect evidence, (3) are mostly applied uniformly for all patients without regard to individual differences, and (4) may be overly restrictive and therefore impede ideal recovery. The purpose of this article is to present an overview of current research and commentary on median sternotomy procedures and activity restrictions. We propose that the optimal degree and duration of SP should be based on an individual patient''s characteristics (eg, risk factors, comorbidities, previous activity level) that would enable physical activity to be targeted to particular limitations rather than restricting specific functional tasks and physical activity. Such patient-specific SP focusing on function may be more likely to facilitate recovery after median sternotomy and less likely to impede it.Key Words: median sternotomy, sternal precautions, physical therapy, exercise protocols     

Evaluation and Opportunities in Overtraining Approaches

Overtraining (OT) as a sports phenomenon can be caused by stressors on various levels (physical, emotional, psychological, and social) and evokes responses on these levels. This study evaluated research and new opportunities in the field of OT by introducing an integrated multidisciplinary approach, based on the single and multistressors approach. The single stressor approach focuses on the training load-recovery imbalance, which results in a stagnating performance, excluding the etiology by nonsport-related factors. The multistressors approach includes all factors as relevant in the etiology of a stagnating performance. In future studies on OT, an integrative approach should not only highlight changes in training regimes and specific responses to training stressors but also focus on the role of training-related recovery, the impact of stressors, and personality factors influencing stress appraisal. This will provide a better insight into the etiology and consequences of OT, necessary for prevention and treatment in sport practice, and enhance the focus on adequate recovery (good sleep, sufficient rest periods) and athletes' stress-related responses.     

The interaction of functional and dysfunctional emotions during balance beam performance

The interaction between functional and dysfunctional emotions, as one of the major tenets of the individual zones of optimal functioning (IZOF) model (Hanin, 2000), was studied in a sport specific setting. Fourteen female gymnasts performed three attempts of a compulsory balance beam routine at three different heights. Heart rate and self-report of functional and dysfunctional emotions were measured during each routine. These data revealed the effectiveness of inducting emotions by manipulating height. Also, performance decreased on the most challenging condition, (i.e., the first attempt on the highest height). Moderated hierarchical regression analysis revealed a significant interaction between functional and dysfunctional emotions only when the dysfunctional emotion level was low.     

Self-regulation in endurance sports: theory,research, and practice

ABSTRACT

There is considerable research interest in psychological aspects of endurance performance. Until recently, research typically lacked a theoretical underpinning, and contemporary research is particularly informed by the psychobiological model of endurance performance. In this critical review, we propose that psychological theories relating to self-regulation, particularly self-efficacy theory and the process model of emotion regulation, could shed more light on how endurance performance is determined and lead to additional understanding of how psychological interventions can be used. We argue that people encounter fewer stressors in most experimental studies than are encountered before and during real-life events. In addition, we argue that most research conducted to date has focused on the forethought and performance phases of self-regulation, rather than the self-reflection phase, and research has not considered the cyclical nature of self-regulation. We also argue that if research participants are not endurance athletes, then their motivation may not be self-determined, and self-regulatory learning may not take place. Recommendations are given for future research, and evidence-based guidance is offered on enhancing performance and improving the quality of experience for endurance athletes.