Slackline Training (Balancing Over Narrow Nylon Ribbons) and Balance Performance: A Meta-Analytical Review. Sports Med. 2017;47:1075-1086. [PMID: 27704483 DOI: 10.1007/s40279-016-0631-9]

Slackline training for Paralympic alpine sit skiers: Development of human-device multi-joint coordination

PURPOSE

Para-alpine sit skiers face unique challenges in balance control due to their disabilities and the use of sit skis. This study assessed their multi-joint coordination before and after slackline training.

METHODS

Nine alpine sit skiers (6 M/3 F; 27 ± 8 years; height: 168.3 ± 6.0 cm; body mass: 55.4 ± 6.9 kg) with different disabilities (LW10-LW12) volunteered for the experiment. All subjects performed slackline training for 5 weeks (20 sessions). Joint kinematics were captured by vision-based markerless motion analysis. Root mean square (RMS) amplitude, mean velocity and mean power frequency (MPF) were evaluated.

RESULTS

After training, performance improved significantly with an increase in balance time (1041%, p = 0.002), and a decrease in joint angular velocities and RMS amplitude of the sit ski foot (p < 0.05). Joint synergies were developed through in- or anti-phase movements between joint pairs, particularly involving the hip joints (continuous relative phase angles ~0° or 180°, p < 0.001). Multi-joint coordination shifted from large-RMS amplitude of elbows to low-MPF large-RMS amplitude of the hip and shoulders (p < 0.05), with a significant increase of hip weighting (77.61%, p = 0.031) in the principal component analysis. The coordination was maintained with the change of slackline tension (p < 0.05). Athletes with severe trunk disabilities (LW10) had shorter balance time and poorer coordination than athletes with full trunk functions (LW12).

CONCLUSIONS

Our findings showed the development of joint coordination involving better control of the hip and sit skis during the challenging slackline training task.

Practice walking on a treadmill-mounted balance beam modifies beam walking sacral movement and alters performance in other balance tasks

The goals of this study were to determine if a single 30-minute session of practice walking on a treadmill mounted balance beam: 1) altered sacral marker movement kinematics during beam walking, and 2) affected measures of balance during treadmill walking and standing balance. Two groups of young, healthy human subjects practiced walking on a treadmill mounted balance beam for thirty minutes. One group trained with intermittent visual occlusions and the other group trained with unperturbed vision. We hypothesized that the subjects would show changes in sacrum movement kinematics after training and that there would be group differences due to larger improvements in beam walking performance by the visual occlusions group. We also investigated if there was any balance transfer from training on the beam to treadmill walking (margin of stability) and to standing static balance (center of pressure excursion). We found significant differences in sacral marker maximal velocity after training for both groups, but no significant differences between the two groups from training. There was limited evidence of balance transfer from beam-walking practice to gait margin of stability for treadmill walking and for single leg standing balance, but not for tandem stance balance. The number of step-offs while walking on a narrow beam had the largest change with training (partial η2 = 0.7), in accord with task specificity. Other balance metrics indicative of transfer had lower effect sizes (partial η2<0.5). Given the limited transfer across balance training tasks, future work should examine how intermittent visual occlusions during multi-task training improve real world functional outcomes.

Effects of stochastic resonance whole-body vibration on sensorimotor function in elderly individuals-A systematic review

Introduction

Due to demographic changes, falls are increasingly becoming a focus of health care. It is known that within six months after a fall, two thirds of fallers will fall again. Therefore, therapeutic procedures to improve balance that are simple and can be performed in a short time are needed. Stochastic resonance whole-body vibration (SR-WBV) may be such a procedure.

Method

An electronic search to assess the effectiveness of SR-WBV on balance in the elderly was conducted using databases that included CINAHL Cochrane, PEDro, and PubMed. Included studies were assessed using the Collaboration Risk of Bias Tool by two independent reviewers.

Results

Nine studies showing moderate methodological quality were included. Treatment parameters were heterogeneous. Vibration frequency ranged from 1 to 12 Hz. Six studies found statistically significant improvements of balance from baseline to post measurement after SR-WBV interventions. One article found clinical relevance of the improvement in total time of the "Expanded Time to Get Up and Go Test".

Discussion

Physiological adaptations after balance training are specific and may explain some of the observed heterogeneity. Two out of nine studies assessed reactive balance and both indicated statistically significant improvements after SR-WBV. Therefore, SR-WBV represents a reactive balance training.

Physical activity does not impact mediolateral margin of stability across a range of postural-perturbing conditions in young adults

BACKGROUND

The maintenance of stability during walking is critical for successful locomotion. While targeted balance training can improve stability, it is unclear how simply meeting recommended physical activity guidelines may impact dynamic stability in healthy young adults.

RESEARCH QUESTION

Examining the differences in the mediolateral margin of stability (ML-MOS) and the variability of the ML-MOS in physically active and inactive young adults across a range of stability-challenging walking tasks METHOD: Twenty-one physically active and twenty inactive young adults completed four experimental walking conditions: (1) Overground Walking, (2) Tandem Walking, (3) Beam Walking, and (4) Stepping-Stones. The ML-MOS and coefficient of variation of the ML-MOS were calculated at each heel strike while participants walked at their preferred walking speed. A two-way mixed-effects ANOVA was conducted to examine the effects of group and condition and their interaction on ML-MOS and ML-MOS variability RESULTS: Neither the ML-MOS nor the variability of the ML-MOS was significantly different between physically active and physically inactive young adults during any experimental walking conditions. A significant main effect of the experimental walking condition was observed, with the ML-MOS decreasing from overground walking to the tandem and beam walking conditions. The ML-MOS also became more variable in the tandem, beam, and stepping-stones conditions than in overground gait.

SIGNIFICANCE

Physical activity status did not influence frontal plane dynamic balance in healthy young adults, even in stability-challenging environments. Conditions that constrain step width, such as tandem and beam walking, are adequate for challenging frontal plane dynamic balance and indicate that trunk kinematics may be adjusted when step width is constrained.

Effects of a Short-Term Slackline Training Program on Energy Expenditure and Balance in Healthy Young Adults: A Preliminary Report of a Randomized Controlled Trial

The development of technology and a fast-paced lifestyle has caused a significant decrease in physical activity, especially among young people. These worrying trends can be countered by the use of attractive forms of physical recreation, including the increasingly popular slackline. The aim of this study was to evaluate energy expenditure during slackline training and to analyze changes in dynamic and static balance parameters after supervised slackline training sessions. The study enrolled 28 healthy volunteers (14 men and 14 women aged 21−25) who were randomly divided into two groups: experimental and passive control. The energy expenditure level was the primary outcome and was assessed using the SenseWear Armband. Each participant underwent an initial and final balance assessment using two selected protocols on the Balance Master platform. The intervention lasted 5 days, with 15 min of supervised training per day. The average energy expenditure expressed in MET was 6.0 (±0.7) MET per training session. An analysis of the results regarding static and dynamic balance showed that the group participating in slackline training significantly improved stability on foam surfaces with their eyes open (p < 0.003), as well as tandem walk speeds (p < 0.05), both with small effect sizes. The results suggested that slackline training has the potential to produce significant positive effects on general health statuses following the World Health Organization’s (WHO) recommendations on physical activity. The significant improvement in task-specific balance suggests that slackline training could become an important element of the prevention and rehabilitation of many injuries.

Learning a new balance task: the influence of prior motor practice on training adaptations

Prior motor experience is thought to aid in the acquisition of new skills. However, studies have shown that balance training does not promote learning of a subsequent balance task. These results stand in contrast to the learning-to-learn paradigm, which is well described for other tasks. We therefore tested if a coordinative affinity between tasks is needed to achieve a learning-to-learn for balance control.Three groups trained different motor tasks during training phase1 (coordination ladder (COOR); bipedal wobble board (2WB); single-leg wobble board (1WB)). During training phase2, all groups trained a tiltboard balance task. Task-specific and transfer effects were evaluated for phase1. A potential learning-to-learn effect was evaluated by comparing the acquisition rates from phase2 for the tiltboard task that was used for training and testing.The results indicate task-specific adaptations after phase1 for 1WB. In contrast, 2WB showed similar improvements than 1WB and COOR (effect sizes: -0.31 to -0.38) when tested on the wobble board with bipedal stance indicating no task-specific improvement for 2WB. For phase2, the linear regression analysis showed larger adaptations for 1WB and 2WB when compared to COOR. This effect implies some uncertainty due to overlapping confidence intervals.Task-specific adaptations after phase1 were found for 1WB but not 2WB. It is discussed that the difficulty of the training task could explain these contrasting results. During phase2, larger adaptations were found for both groups that trained balance tasks during phase1. Thus, despite some uncertainty, prior balance training appears to promote adaptations of a subsequently learned balance task.

Slacklining: A narrative review on the origins, neuromechanical models and therapeutic use

Slacklining, the neuromechanical action of balance retention on a tightened band, is achieved through self-learned strategies combining dynamic stability with optimal energy expenditure. Published slacklining literature is recent and limited, including for neuromechanical control strategy models. This paper explores slacklining's definitions and origins to provide background that facilitates understanding its evolution and progressive incorporation into both prehabilitation and rehabilitation. Existing explanatory slacklining models are considered, their application to balance and stability, and knowledge-gaps highlighted. Current slacklining models predominantly derive from human quiet-standing and frontal plane movement on stable surfaces. These provide a multi-tiered context of the unique and complex neuro-motoric requirements for slacklining's multiple applications, but are not sufficiently comprehensive. This consequently leaves an incomplete understanding of how slacklining is achieved, in relation to multi-directional instability and complex multi-dimensional human movement and behavior. This paper highlights the knowledge-gaps and sets a foundation for the required explanatory control mechanisms that evolve and expand a more detailed model of multi-dimensional slacklining and human functional movement. Such a model facilitates a more complete understanding of existing performance and rehabilitation applications that opens the potential for future applications into broader areas of movement in diverse fields including prostheses, automation and machine-learning related to movement phenotypes.

Slacklining as therapy to address non-specific low back pain in the presence of multifidus arthrogenic muscle inhibition

Low back pain (LBP) represents the most prevalent, problematic and painful of musculoskeletal conditions that affects both the individual and society with health and economic concerns. LBP is a heterogeneous condition with multiple diagnoses and causes. In the absence of consensus definitions, partly because of terminology inconsistency, it is further referred to as non-specific LBP (NSLBP). In NSLBP patients, the lumbar multifidus (MF), a key stabilizing muscle, has a depleted role due to recognized myocellular lipid infiltration and wasting, with the potential primary cause hypothesized as arthrogenic muscle inhibition (AMI). This link between AMI and NSLBP continues to gain increasing recognition. To date there is no 'gold standard' or consensus treatment to alleviate symptoms and disability due to NSLBP, though the advocated interventions are numerous, with marked variations in costs and levels of supportive evidence. However, there is consensus that NSLBP management be cost-effective, self-administered, educational, exercise-based, and use multi-modal and multi-disciplinary approaches. An adjuvant therapy fulfilling these consensus criteria is 'slacklining', within an overall rehabilitation program. Slacklining, the neuromechanical action of balance retention on a tightened band, induces strategic indirect-involuntary therapeutic muscle activation exercise incorporating spinal motor control. Though several models have been proposed, understanding slacklining's neuro-motor mechanism of action remains incomplete. Slacklining has demonstrated clinical effects to overcome AMI in peripheral joints, particularly the knee, and is reported in clinical case-studies as showing promising results in reducing NSLBP related to MF deficiency induced through AMI (MF-AMI). Therefore, this paper aims to: rationalize why and how adjuvant, slacklining therapeutic exercise may positively affect patients with NSLBP, due to MF-AMI induced depletion of spinal stabilization; considers current understandings and interventions for NSLBP, including the contributing role of MF-AMI; and details the reasons why slacklining could be considered as a potential adjuvant intervention for NSLBP through its indirect-involuntary action. This action is hypothesized to occur through an over-ride or inhibition of central down-regulatory induced muscle insufficiency, present due to AMI. This subsequently allows neuroplasticity, normal neuro-motor sequencing and muscle re-activation, which facilitates innate advantageous spinal stabilization. This in-turn addresses and reduces NSLBP, its concurrent symptoms and functional disability. This process is hypothesized to occur through four neuro-physiological processing pathways: finite neural delay; movement-control phenotypes; inhibition of action and the innate primordial imperative; and accentuated corticospinal drive. Further research is recommended to investigate these hypotheses and the effect of slacklining as an adjuvant therapy in cohort and control studies of NSLBP populations.

Slacklining: An explanatory multi-dimensional model considering classical mechanics, biopsychosocial health and time

This paper aims to overcome slacklining's limited formulated explanatory models. Slacklining is an activity with increasing recreational use, but also has progressive adoption into prehabilitation and rehabilitation. Slacklining is achieved through self-learned strategies that optimize energy expenditure without conceding dynamic stability, during the neuromechanical action of balance retention on a tightened band. Evolved from rope-walking or 'Funambulus', slacklining has an extensive history, yet limited and only recent published research, particularly for clinical interventions and in-depth hypothesized multi-dimensional models describing the neuromechanical control strategies. These 'knowledge-gaps' can be overcome by providing an, explanatory model, that evolves and progresses existing standards, and explains the broader circumstances of slacklining's use. This model details the individual's capacity to employ control strategies that achieve stability, functional movement and progressive technical ability. The model considers contributing entities derived from: Self-learned control of movement patterns; subjected to classical mechanical forces governed by Newton's physical laws; influenced by biopsychosocial health factors; and within time's multi-faceted perspectives, including as a quantified unit and as a spatial and cortical experience. Consequently, specific patient and situational uses may be initiated within the framework of evidence based medicine that ensures a multi-tiered context of slacklining applications in movement, balance and stability. Further research is required to investigate and mathematically define this proposed model and potentially enable an improved understanding of human functional movement. This will include its application in other diverse constructed and mechanical applications in varied environments, automation levels, robotics, mechatronics and artificial-intelligence factors, including machine learning related to movement phenotypes and applications.

Task-Related Hemodynamic Response Alterations During Slacklining: An fNIRS Study in Advanced Slackliners

The ability to maintain balance is based on various processes of motor control in complex neural networks of subcortical and cortical brain structures. However, knowledge on brain processing during the execution of whole-body balance tasks is still limited. In the present study, we investigated brain activity during slacklining, a task with a high demand on balance capabilities, which is frequently used as supplementary training in various sports disciplines as well as for lower extremity prevention and rehabilitation purposes in clinical settings. We assessed hemodynamic response alterations in sensorimotor brain areas using functional near-infrared spectroscopy (fNIRS) during standing (ST) and walking (WA) on a slackline in 16 advanced slackliners. We expected to observe task-related differences between both conditions as well as associations between cortical activity and slacklining experience. While our results revealed hemodynamic response alterations in sensorimotor brain regions such as primary motor cortex (M1), premotor cortex (PMC), and supplementary motor cortex (SMA) during both conditions, we did not observe differential effects between ST and WA nor associations between cortical activity and slacklining experience. In summary, these findings provide novel insights into brain processing during a whole-body balance task and its relation to balance expertise. As maintaining balance is considered an important prerequisite in daily life and crucial in the context of prevention and rehabilitation, future studies should extend these findings by quantifying brain processing during task execution on a whole-brain level.

Balance training monitoring and individual response during unstable vs. stable balance Exergaming in elderly adults: Findings from a randomized controlled trial

OBJECTIVE

Exercise-based fall prevention programs mainly refer to multimodal and challenging balance exercises. Individual load monitoring and interpretations are crucial to enable adequate adaptation responses on the individual level. Thus, assessing internal responses to external stimuli throughout an intervention period need to be adequately addressed. The aim of this secondary analysis of a 3-armed randomized controlled trial was to analyze internal and external loads of unstable vs. stable balance Exergame training in healthy seniors. We intended to elucidate whether differences of external and internal load criteria occur over the intervention period.

METHODS

A total of 51 healthy seniors (females: n = 34; males: n = 17; age: 69 ± 6 years; BMI: 27 ± 5) were allocated to either volitional stepping (VOL), volitional stepping under unstable conditions (VOL + US) or an inactive control group (CON). VOL and VOL + US completed 8 weeks of Exergame based step training (three weekly sessions, 45 min each) using the Dividat Senso device. Twelve different balance Exergames were used, consisting of virtual reality like video games. The original nonswinging, stable platform was employed for VOL, whereas VOL + US used an adapted Senso mounted on a swinging Posturomed Rack. The instability level was increased for VOL + US only every second week. External (game scores) and internal (perceived efforts, using the rated perceived exertion scale (RPE)) load measures were individually recorded for every session. Statistical analysis was carried out using linear mixed-effects modelling.

RESULTS

Although VOL + US completed similar games at identical training volumes under unstable conditions, the achieved game scores did not significantly differ between both training groups (p = 0.71). Both intervention groups notably improved their game scores over the 8 training weeks (p < 0.01). A significant time x group interaction effect was observed for perceived effort (p < 0.01), serving as an internal load measure. Subsequent post-hoc testing revealed significant greater perceived exertion values in each of the first 7 weeks (p < 0.05) in VOL + US compared to VOL. No between-group differences were found for RPE in week 8. Whereas RPE values in VOL + US decreased over time (week 1: 4.6 ± 1.9; week 8: 3.1 ± 1.6), VOL indicated similar RPE values for all weeks (week 1: 3.1 ± 1.3; week 8: 2.9 ± 1.4). A detailed analysis of all twelve games revealed that differences in perceived exertion depend on the game content: in 75% of the involved games the RPE level was significantly higher in VOL + US compared to VOL (p < 0.05).

CONCLUSION

Monitoring internal and external loads on individual level are paramount for gaining adequate training adaptations. Our results indicate that between-group differences in perceived efforts a) can funnel over time, b) depend on game content and c) do not necessarily affect overall scoring. Future studies should individually employ and monitor measures of perceived efforts to guarantee an adequate challenge to the balance system within exercise-based fall prevention programs.

Balance abilities of junior ice hockey players

BACKGROUND

Postural control is required during various fast-paced and offensive ice hockey actions, and therefore seems to be an important component in ice hockey performance.

METHODS

Data were collected from two ice hockey teams with differing performance levels. The higher-performance team consisted of 26 players (with ages of 16.3±0.9 y, heights of 178.26±6.71 cm, and weights of 74.3±9.6 kg). The lower-performance team consisted of 19 players (with ages of 16.2±1.8 y, heights of 176.11±9.81 cm, and weights of 68.7±13.9 kg). Each participant performed six unilateral stances under static conditions on a balance pad placed on a force platform and five bilateral stances under dynamic conditions using a wobble board placed on the force platform.

RESULTS

The higher-level players performed better in the unilateral static stance task in both the anterior-posterior direction and the medial-lateral direction (with a P value of P<0.001), and total velocity (P=0.001). The higher-level players also performed better in both the anterior-posterior and medial-lateral directions, and total velocity (with P value of P<0.001), in the bilateral dynamic stance task and therefore performed significantly better than the lower-level players.

CONCLUSIONS

Hockey players who possess a highly developed postural control strategy have a superior ability to compensate for unexpected postural disturbances and collisions, and thus possess a strong competitive advantage. Therefore, testing the balance abilities of hockey players under static and dynamic conditions may be useful for evaluating their competitive performance levels.

Which Effects on Neuroanatomy and Path-Integration Survive? Results of a Randomized Controlled Study on Intensive Balance Training

Balancing is a complex task requiring the integration of visual, somatosensory and vestibular inputs. The vestibular system is linked to the hippocampus, a brain structure crucial for spatial orientation. Here we tested the immediate and sustained effects of a one-month-long slackline training program on balancing and orientation abilities as well as on brain volumes in young adults without any prior experience in that skill. On the corrected level, we could not find any interaction effects for brain volumes, but the effect sizes were small to medium. A subsequent within-training-group analysis revealed volumetric increments within the somatosensory cortex and decrements within posterior insula, cerebellum and putamen remained stable over time. No significant interaction effects were observed on the clinical balance and the spatial orientation task two months after the training period (follow-up). We interpret these findings as a shift away from processes crucial for automatized motor output towards processes related to voluntarily controlled movements. The decrease in insular volume in the training group we propose to result from multisensory interaction of the vestibular with the visual and somatosensory systems. The discrepancy between sustained effects in the brain of the training group on the one hand and transient benefits in function on the other may indicate that for the latter to be retained a longer-term practice is required.

Six weeks of balance or power training induce no generalizable improvements in balance performance in healthy young adults

Background

Training programs for fall prevention often fail to induce large general effects. To improve the efficacy of fall prevention programs, it is crucial to determine which type of training is most effective in inducing generalizable effects, i.e., improvements in untrained situations. Two likely candidates are balance and resistance training. Here, we assessed whether either varied balance training or a training program aiming to increase leg power would improve performance and acquisition rate of a novel balance task.

Methods

Forty-two healthy recreationally active subjects (16 females, age 24 ± 3y) were assigned to a control group, a varied practice balance group or a loaded squat and plyometrics power group, training for 6 weeks (twice per week, 40 min per session). Before and after the training, we measured peak power in countermovement jumps and balance performance in two different untrained balance tasks (10 trials pre and 50 trials post-training).

Results

After training, the performance and the acquisition rate in the two untrained tasks were similar for all groups (no group x time interaction), i.e., no generalization of learning effect was induced by either form of training. Peak power in the countermovement jump did not change significantly in any of the groups.

Conclusions

Neither a six-week power training nor a varied balance training improved performance or acquisition of an untrained balance task. This underpins the task-specificity principle of training and emphasizes the need for studies that assess the mechanisms of transfer and generalization, thus helping to find more effective intervention programs for fall prevention.

Cortical, subcortical and spinal neural correlates of slackline training-induced balance performance improvements

Humans develop posture and balance control during childhood. Interestingly, adults can also learn to master new complex balance tasks, but the underlying neural mechanisms are not fully understood yet. Here, we combined broad scale brain connectivity fMRI at rest and spinal excitability measurements during movement. Six weeks of slackline training improved the capability to walk on a slackline which was paralleled by functional connectivity changes in brain regions associated with posture and balance control and by task-specific changes of spinal excitability. Importantly, the performance of trainees was not better than control participants in a different, untrained balance task. In conclusion, slackline training induced large-scale neuroplasticity which solely transferred into highly task specific performance improvements.

Individually tailored whole-body vibration training to reduce symptoms of chemotherapy-induced peripheral neuropathy: study protocol of a randomised controlled trial-VANISH

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is a prevalent and clinically meaningful side effect of cancer treatment. CIPN is induced by neurotoxic agents, causing severe sensory and/or motor deficits, resulting in disability and poor recovery, reducing patients' quality of life and limiting medical therapy. To date, effective treatment options are lacking. Whole-body vibration (WBV) training can attenuate motor and sensory deficits. We are conducting a two-armed, multicentre, assessor-blinded, randomised controlled trial, to investigate the effects of WBV on relevant symptoms of CIPN and determine the training characteristics.

METHODS AND ANALYSIS

In this ongoing study, 44 patients who have completed therapy in the past 3 months, with a neurologically confirmed CIPN are assessed before and after a 12-week intervention and follow-up. The intervention group receives WBV twice a week. Exercises are individually tailored according to the initially determined optimal neuromuscular response. The control group receives care as usual.Primary endpoint is the patient reported reduction of CIPN-related symptoms (Functional Assessment of Cancer Therapy/Gynaecology Oncology Group-Neurotoxicity). Secondary endpoints are compound muscle action potentials, distal motor latency, conduction velocity, F-waves from the tibial and peroneal nerve, antidromic sensory nerve conduction studies of the sural nerve, normalised electromyographic activity, peripheral deep sensitivity, proprioception, balance, pain, the feasibility of training settings, quality of life and the level of physical activity.

AIM, ETHICS AND DISSEMINATION

The study was approved by both responsible ethics committees. (1) Our results may contribute to a better understanding of the effects of WBV on motor and sensory functions and (2) may provide information whether WBV at the most effective setting, is feasible for neuropathic patients. (3) Our results may also contribute to improve supportive care in oncology, thereby enhancing quality of life and enabling the optimal medical therapy. All results will be published in international peer-reviewed journals as well as a manual for clinical practice.

TRIAL REGISTRATION NUMBER

NCT03032718.

Brain Gray Matter Volume Is Modulated by Visual Input and Overall Learning Success but Not by Time Spent on Learning a Complex Balancing Task

To better understand the process of neuroplasticity, this study assesses brain changes observed by voxel-based morphometry (VBM) in response to two different learning conditions. Twenty-two young, healthy subjects learned slacklining, a complex balancing task, with either their eyes open (EO, n = 11) or their eyes closed (EC, n = 11). The learning took place three times per week for four weeks, with learning periods of 1 hour, providing a total of 12 hours of learning. The scanning and testing protocols were applied at three time-points: (1) immediately before learning (baseline), (2) immediately afterwards (post-test), and (3) two months afterwards (follow-up). The EO group performed better on the task-specific test. Significant group*time interaction effects were found in sensory-motor areas at the post-test, with increases in the EO group only. The results suggest that VBM-observed brain changes in response to learning a complex balancing task vary depending on the learning success and the availability of visual input, and not solely on the amount of time spent on learning. These findings should be taken into account by future studies using similar methodologies.

Three months of slackline training elicit only task-specific improvements in balance performance

Slackline training is a challenging and motivating type of balance training, with potential usefulness for fall prevention and balance rehabilitation. However, short-term slackline training seems to elicit mostly task-specific performance improvements, reducing its potential for general fall prevention programs. It was tested whether a longer duration slackline training (three months, 2 sessions per week) would induce a transfer to untrained tasks. Balance performance was tested pre and post slackline training on the slackline used during the training, on a slackline with different slack, and in 5 different non-trained static and dynamic balance tasks (N training = 12, N control = 14). After the training, the training group increased their performance more than the control group in both of the slackline tasks, i.e. walking on the slackline (time × group interaction with p < 0.001 for both tasks). However, no differences between groups were found for the 5 non-trained balance tasks, only a main effect of time for four of them. The long-term slackline training elicited large task-specific performance improvements but no transfer to other non-trained balance tasks. The extensive slackline training that clearly enhanced slackline performance did not improve the capability to keep balance in other tasks and thus cannot be recommended as a general fall prevention program. The significant test-retest effect seen in most of the tested tasks emphasizes the need of a control group to adequately interpret changes in performance following balance training.

Tai Chi for older adults with chronic multisite pain: a randomized controlled pilot study

BACKGROUND

Chronic pain is associated with poorer cognition and mobility, and fall risk in older adults.

AIMS

To investigate the feasibility of a randomized controlled trial of mind-body exercise (Tai Chi) versus light physical exercise in older adults with multisite pain.

METHODS

Adults aged ≥ 65 years with multisite pain who reported falling in the past year or current use of an assistive device were recruited from Boston area communities. Participants were randomized to either a Tai Chi or a light physical exercise program, offered twice weekly for 12 weeks. The primary outcomes were feasibility and acceptability. Secondary outcomes included pain characteristics, cognition, physical function, gait mobility, fear of falling, and fall rate.

RESULTS

Of 176 adults screened, 85 were eligible, and 54 consented and enrolled (average age 75 ± 8 years; 96.30% white; 75.93% female). The dropout rate was 18% for Tai Chi and 12% for light physical exercise. For those completing the study, exercise class attendance rate was 76% for Tai Chi and 82% for light physical exercise. There were no significant group differences in most secondary outcomes. Tai Chi significantly lowered pain severity (4.58 ± 1.73 to 3.73 ± 1.79, p < 0.01) and pain interference (4.20 ± 2.53 to 3.16 ± 2.28, p < 0.05), reduced fear of falling (90.82 ± 9.59 to 96.84 ± 10.67, p < 0.05), and improved several single-task and dual-task gait variables, while light physical exercise did not change these measures.

DISCUSSION AND CONCLUSIONS

This study demonstrated the feasibility and acceptability of conducting a larger randomized controlled trial in older adults with multisite pain. Study findings and challenges encountered will inform future research.

Short-term slackline training improves task-specific but not general balance in female handball players

Slackline training has been shown to improve balance and neuromuscular performance. However, recent studies suggested that balance is task-specific, implying that transferability of balance skills is limited and might depend on the similarity of the tasks. This study therefore investigated if short-term slackline training could improve performance in balance tasks that are either more or less similar to the trained slackline task. Furthermore, we assessed potential transfer effects to other neuromuscular performance tests. 25 female handball players (23.7 ± 3.9 years) participated in our study and were matched to either a slackline training (SLT; n = 14) or a control group (CON; n = 11). The intervention comprised 12 sessions with overall 120 minutes of slackline training using single and double slacklines. Slackline standing time and measures of dynamic and static balance were assessed before and after the intervention, as well as power and sprint-related performance parameters. Two-way repeated-measures ANOVA found a significant group × time interaction for slackline standing time, indicating larger training effects for SLT. For the remaining dynamic and static balance tests, no significant interactions were found. With regard to neuromuscular performance, there was a significant group × time interaction only in change of direction. In essence, the study showed that slackline training induced task-specific balance improvements without affecting general balance. This adds further evidence to the task-specificity principle of balance, although the specificity of the sample as well as the briefness of the intervention should be taken into account when generalizing our findings. Nonetheless, this study contains practical implications for team sports interventions and future balance training studies, highlighting the importance of selecting appropriate balance exercises to yield rapid and the desired training outcomes.

Additional Intra- or Inter-session Balance Tasks Do Not Interfere With the Learning of a Novel Balance Task

Background: It has been shown that balance training induces task-specific performance improvements with very limited transfer to untrained tasks. Thus, regarding fall prevention, one strategy is to practice as many tasks as possible to be prepared for a multitude of situations with increased fall risk. However, it is not clear whether the learning of several different balance tasks interfere with each other. A positive influence could be possible via the contextual interference (CI) effect, a negative influence could be induced by the disruption of motor memory during consolidation or retrieval.

Methods: In two 3-week training experiments, we tested: (1) whether adding an additional balance task in the same training session would influence the learning of a balance task [first task: one-leg stance on a tilt-board (TB), six sessions, 15 × 20 s per session; additional task: one-leg stance on a slack line (SL), same amount of additional training]; (2) whether performing a different balance task (SL) in between training sessions of the first task (TB) would influence the learning of the first task. Twenty-six healthy subjects participated in the first experiment, 40 in the second experiment. In both experiments the participants were divided into three groups, TB only, TB and SL, and control. Before and after the training period, performance during the TB task (3 × 20 s) was recorded with a Vicon motion capturing system to assess the time in equilibrium.

Results: Analyses of variance revealed that neither the additional intra-session balance task in experiment 1 nor the inter-session task in experiment 2 had a significant effect on balance performance improvement in the first task (no significant group × time interaction effect for the training groups, p = 0.83 and p = 0.82, respectively, only main effects of time).

Conclusion: We could not find that additional intra- or intersession balance tasks interfere with the learning of a balance task, neither impairing it nor having a significant positive effect. This can also be interpreted as further evidence for the specificity of balance training effects, as different balance tasks do not seem to elicit interacting adaptations.

How to Construct, Conduct and Analyze an Exercise Training Study?

Randomized controlled trials (RCTs) can be regarded as gold standard in investigating dose-response and causal relationships in exercise science. Recommendations for exercise training routines and efficacy analyses of certain training regimen require valid data derived from robust RCTs. Moreover, meta-analyses rely on RCTs and both RCTs and meta-analyses are considered the highest level of scientific evidence. Beyond general study design a variety of methodological aspects and notable pitfalls has to be considered. Therefore, exercise training studies should be carefully constructed focusing on the consistency of the whole design "package" from an explicit hypothesis or research question over study design and methodology to data analysis and interpretation. The present scoping review covers all main aspects of planning, conducting, and analyzing exercise based RCTs. We aim to focus on relevant aspects regarding study design, statistical power, training planning and documentation as well as traditional and recent statistical approaches. We intend to provide a comprehensive hands-on paper for conceptualizing future exercise training studies and hope to stimulate and encourage researchers to conduct sound and valid RCTs in the field of exercise training.

Effects of traditional balance and slackline training on physical performance and perceived enjoyment in young soccer players

The aim of this study was to evaluate the effects of 12-week balance and slackline training programs on physical performance and perceived enjoyment scale in young soccer players. Forty-one preadolescent soccer players were assigned to two experimental groups performing traditional balance (BLT) or slackline training (SLT), and a control group. Pre-post assessment encompassed Balance Error Scoring System (BESS), Star Excursion Balance test (SEBT), sprint with 90° turns (S90), and countermovement jump (CMJ). The rate of perceived enjoyment scale (PACES) was applied at the end of the experimental period. SLT and BLT improved similarly in BESS, SEBT and S90. No changes were detected in the CMJ. Regarding PACES score, SLT presented significantly higher values than BLT. Young athletes may benefit from a motivating training approach, thus, a designed program based on slackline drills should be preferable to improve physical performance in terms of balance and change of direction ability in preadolescent soccer players.

Motor learning of a dynamic balance task: Influence of lower limb power and prior balance practice

OBJECTIVES

We wanted to verify if the "learning to learn" effect observed in the learning of visuomotor tasks is also present when learning a balance task, i.e., whether the learning rate of a balance task is improved by prior practice of similar balance tasks.

DESIGN

Single centre, parallel group, controlled training study.

METHODS

32 young healthy participants were divided into a control and a training group. The training group's practice consisted of 90 trials of three balance tasks. Forty-eight hours after the training, we recorded performance during the acquisition (90 trials) of a novel balance task in both groups, and 24h thereafter we measured its retention (10 trials).

RESULTS

Mixed models statistical analysis showed that the learning rate of both the acquisition and the retention phase was not influenced by the 90 prior practice trials performed by the training group. However, participants with high lower limb power had a higher balance performance than participants with low power, which can be partly explained by the higher learning rate observed during the acquisition phase for participants with high power.

CONCLUSIONS

Contrary to visuomotor or perceptual tasks, we did not find a "learning to learn" effect for balance tasks. The correlation between learning rate and lower limb power suggests that motor learning of dynamic balance tasks may depend on the physical capability to execute the correct movement. Thus, a prior strength and conditioning program with emphasis on lower limb power should be considered when designing a balance training, especially in fall prevention.

Changes in balance coordination and transfer to an unlearned balance task after slackline training: a self-organizing map analysis

How humans maintain balance and change postural control due to age, injury, immobility or training is one of the basic questions in motor control. One of the problems in understanding postural control is the large set of degrees of freedom in the human motor system. Therefore, a self-organizing map (SOM), a type of artificial neural network, was used in the present study to extract and visualize information about high-dimensional balance strategies before and after a 6-week slackline training intervention. Thirteen subjects performed a flamingo and slackline balance task before and after the training while full body kinematics were measured. Range of motion, velocity and frequency of the center of mass and joint angles from the pelvis, trunk and lower leg (45 variables) were calculated and subsequently analyzed with an SOM. Subjects increased their standing time significantly on the flamingo (average +2.93 s, Cohen's d = 1.04) and slackline (+9.55 s, d = 3.28) tasks, but the effect size was more than three times larger in the slackline. The SOM analysis, followed by a k-means clustering and marginal homogeneity test, showed that the balance coordination pattern was significantly different between pre- and post-test for the slackline task only (χ ² = 82.247; p < 0.001). The shift in balance coordination on the slackline could be characterized by an increase in range of motion and a decrease in velocity and frequency in nearly all degrees of freedom simultaneously. The observation of low transfer of coordination strategies to the flamingo task adds further evidence for the task-specificity principle of balance training, meaning that slackline training alone will be insufficient to increase postural control in other challenging situations.

Could Slackline Training Complement the FIFA 11+ Programme Regarding Training of Neuromuscular Control?

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.

Traditional balance and slackline training are associated with task-specific adaptations as assessed with sensorimotor tests

The purpose of this study was to measure alterations in sensorimotor skills and balance resulting from slackline training and conventional balance training. Forty-three physically fit subjects were randomized into three groups. Two groups practiced three times a week for 15 minutes, including at least once supervised session, on the slackline or perform conventional balance training for 6 weeks. The control group was not allowed to perform any balance training. Before and after the intervention, the subjects underwent sensorimotor and strength tests. The results of our intra-class correlation analysis showed that the stability parameters from the multifunctional training device (MFT, 0.7), the height during the countermovement jump (CMJ, 0.95) and the maximum force (0.88) during leg press showed excellent reliability. A post hoc comparison indicated a larger effect of conventional training (almost 11% reduction in MFT stability) compared with slackline training in group-wide comparisons of the pre- to the post-training measurements. The factor analysis showed that stability and sensorimotor assessment using MFT were correlated, as were height during CMJ and maximal force during leg press, which represented dynamic strength. Because CMJ had the highest intra-class correlation value, it was chosen over maximum force from leg press. For these reasons, only two out of nine measured parameters, namely MFT stability and CMJ, were analysed across groups. The only observed difference between the two groups was MFT stability (slackline - 1.5%, conventional - 13%), whereas the improvement of CMJ was the same (slackline + 3%, conventional + 3%). It can be concluded that slacklining is partly complementary to conventional sensorimotor training.

Improvements in Orientation and Balancing Abilities in Response to One Month of Intensive Slackline-Training. A Randomized Controlled Feasibility Study

Background: Slackline-training has been shown to improve mainly task-specific balancing skills. Non-task specific effects were assessed for tandem stance and preferred one-leg stance on stable and perturbed force platforms with open eyes. It is unclear whether transfer effects exist for other balancing conditions and which component of the balancing ability is affected. Also, it is not known whether slackline-training can improve non-visual-dependent spatial orientation abilities, a function mainly supported by the hippocampus.

Objective: To assess the effect of one-month of slackline-training on different components of balancing ability and its transfer effects on non-visual-dependent spatial orientation abilities.

Materials and Methods: Fifty subjects aged 18–30 were randomly assigned to the training group (T) (n = 25, 23.2 ± 2.5 years; 12 females) and the control group (C) (n = 25, 24.4 ± 2.8 years; 11 females). Professional instructors taught the intervention group to slackline over four consecutive weeks with three 60-min-trainings in each week. Data acquisition was performed (within 2 days) by blinded investigators at the baseline and after the training. Main outcomes Improvement in the score of a 30-item clinical balance test (CBT) developed at our institute (max. score = 90 points) and in the average error distance (in centimeters) in an orientation test (OT), a triangle completion task with walking and wheelchair conditions for 60°, 90°, and 120°.

Results: Training group performed significantly better on the closed-eyes conditions of the CBT (1.6 points, 95% CI: 0.6 to 2.6 points vs. 0.1 points, 95% CI: –1 to 1.1 points; p = 0.011, ηp2 = 0.128) and in the wheelchair (vestibular) condition of the OT (21 cm, 95% CI: 8–34 cm vs. 1 cm, 95% CI: –14–16 cm; p = 0.049, ηp2 = 0.013).

Conclusion: Our results indicate that one month of intensive slackline training is a novel approach for enhancing clinically relevant balancing abilities in conditions with closed eyes as well as for improving the vestibular-dependent spatial orientation capability; both of the benefits are likely caused by positive influence of slackline-training on the vestibular system function.