Perceived cognitive fatigue has only marginal effects on static balance control in healthy young adults.

We examined the influence of perceived cognitive fatigue on static balance control in healthy young adults to gain greater clarity about this issue than provided in previous research. Based on the prevailing assumption in pertinent literature, we hypothesized that the influence of cognitive fatigue on balance control depends on the attentional effort required by the balance tasks being performed. To test this hypothesis, 44 young adults (24 women and 20 men) were alternately assigned to either the experimental group that was cognitively fatigued (using the 16-min TloadDback-task with individualized settings) or the control group (who watched a documentary). Before and after the intervention, the participants performed six balance tasks that differed in (attentional) control requirements, while recording the center of pressure (COP). From these time series, sway variability, mean speed, and sample entropy were calculated and analyzed statistically. Additionally, perceived cognitive fatigue was assessed using VAS scales. Statistical analyses confirmed that the balance tasks differed in control characteristics and that cognitive fatigue was elevated in the experimental group, but not in the control group. Nevertheless, no significant main effects of cognitive fatigue were found on any of the COP measures of interest, except for some non-robust interaction effects related primarily to sample entropy. These results suggest that, in young adults, postural control in static balance tasks is largely automatic and unaffected by task-induced state fatigue.

Influence of Target Width and Distance on Postural Adjustments in a Fencing Lunge.

The aim of this study was to examine whether target width and target distance influence the planning phase of a fencing lunge (early and anticipatory postural adjustments) as well as the execution phase of a fencing lunge. Eight elite female fencers participated in the study. The displacement of the center of foot pressure, muscle activity of the tibialis anterior, and kinematics of center of mass were recorded using force plates. The results show that target width and distance have no effect on early and anticipatory postural adjustments as well as the acceleration and velocity of the center of mass at the moment of foot-off. However, a greater target distance was associated with a greater max center of mass acceleration and velocity, and larger target width resulted in a greater max center of mass acceleration during lunging (p < 0.05). We suppose that the effect of task parameters on preparing a fencing lunge may be mitigated due to the specific technique adopted by expert fencers and the ballistic nature of a fencing lunge.

The influence of walking speed and effects of signal processing methods on the level of human gait regularity during treadmill walking.

BACKGROUND: In recent years the use of sample entropy (SampEn) to evaluate the complexity of the locomotor system in human gait data has gained in popularity. However, it has been suggested that SampEn is sensitive to various input parameters and signal preprocessing methods. This study quantified the effects of different temporal and spatial normalization approaches and various lengths of the template vector (m) on SampEn calculations. The discriminatory ability of SampEn was studied by comparing two walking conditions. METHODS: Twenty-three participants (seven males, 55.7 ± 8.5 years, 165.7 ± 7.9 cm, 80.5 ± 16.7 kg) walked on a treadmill with preferred (Vpref) and maximum (Vmax) speed. Data were segmented and resampled (SEGM), resampled and spatially normalized (NORM), resampled and detrended (ZERO). RESULTS: For vertical ground reaction force (vGRF) and center of pressure in anterio-posterior direction (COPap), in both walking conditions, SampEn was generally sensitive to the vector length and not to the data processing, except for COPap in ZERO, m = 2, 4. For the COPml SampEn behaved oppositely, it was sensitive to preprocessing method and not to the m length. The regularity of COPap and vGRF in all processed signals increased in Vmax condition. For the COPml only two signals, WHOLE and ZERO, revealed increased complexity caused by more demanding walking conditions. CONCLUSIONS: SampEn was able to discriminate between different walking conditions in all analyzed variables, but not in all signals. Depending on evaluated variable, SampEn was susceptible in different way for the m level and processing method. Hence, these should be checked and selected for each variable independently. For future studies evaluating influence of walking velocity on COP and vGRF regularity during treadmill walking it is advised to use raw time series. Furthermore, to maintain template vector which represents biological relevance it is advised to detect highest frequencies present in analyzed signals and evaluate minimal time interval which can reflect change caused by response of a neuromuscular system. During evaluating treadmill walking measured with 100 Hz sampling frequency it is recommended to adopt m from 6 to 10, when average stride time is up to about 1 s.

Effect of Whole-Body Vibration Training on Selected Intrinsic Risk Factors in Women Aged 60+ at Fall Risk: A Randomized Controlled Trial.

The aim of the study was to determine whether Whole Body Vibration Training (WBVT) affects intrinsic risk factors for falls in women aged 60+ at fall risk. DESIGN: Randomized controlled clinical trial. Blinding was applied to the persons in charge of evaluating the intervention's clinical results and statistical analysis. METHODS: Forty-two women over 60 years old were randomly assigned to an experimental group (EG-12-week WBVT; n = 22) and a control group (CG-no additional physical activities; n = 20). Fear of falling was measured by the FES-I questionnaire, gait and dynamic balance using the Time-Up and Go test (TUG), aerobic endurance with the 6-Minute Walk Test (6MWT), and the functional strength of the lower body muscles with the 30-s Chair Stand Test (30SCST) at baseline and post-intervention. Additionally assayed were participants' blood concentrations of interleukin-6 (IL-6). RESULTS: The 12-week WBVT improves gait and balance (TUG, p = 0.009), exercise tolerance (6MWT, p = 0.001), and functional strength (30SCST; p = 0.027) but does not reduce the intensity of fear of falling (FES-I, p = 0.655) and the IL-6 serum concentration (p = 0.377). CONCLUSIONS: WBVT affects selected fall risk factors in women aged 60+ at fall risk.

The effect of a light finger touch on the signal complexity during quiet standing.

The purpose of the study was to investigate the influence of additional tactile information (light fingertip touch) on the postural sway and regularity of center-of-pressure (COP) fluctuations. Thirty-two young, healthy participants performed a quiet standing task (30 s) on a force platform with and without light fingertip touch. COP time-series were analyzed using standard postural sway measures (range, root mean square error, velocity), COP regularity was measured with Sample entropy. Participants demonstrated significantly smaller postural sway with a light touch, but only in the anteroposterior direction. The amount of sway with additional tactile information in the sagittal plane reached the level of sway in the frontal plane without this information. Similarly, COP fluctuations were more irregular during light touch condition only in the anteroposterior direction, as evidenced by significantly higher Sample entropy. Furthermore, COP regularity decreased in the sagittal plane and reached level in the frontal plane without light touch. These results suggest that postural sway is mostly controlled in the sagittal plane and that in the mediolateral direction the control is mostly automated. In conclusion, our results support the notion that the light touch provides additional information which enhances postural stabilization. Our results expand the relation between COP regularity and the attention invested in posture in the touch domain and prove that light touch, as an attentional demanding task, leads to increased COP irregularity. Nonlinear measures of signal regularity (i.e., SampEn) provide surplus insight into human postural control and can be used as an additional useful tool to traditional balance measures.

Biomechanical measures of balance after balance-based exergaming training dedicated for patients with Parkinson's disease.

INTRODUCTION: Although previous studies have contributed to our understanding of the effects of implementing the virtual reality as a rehabilitation tool in patients with Parkinson's disease (PD), additional research is needed to examine the effects of applying balance-based exergaming training on quantitative biomechanical measures of balance. RESEARCH QUESTION: To investigate the effects of balance-based conventional and exergaming training on posture parameters. METHODS: The study involved 24 patients with PD (Hoehn and Yahr stages II-III).Participants underwent twelve training sessions during the 4-week training period. The experimental group (n=12) was trained with a custom-made exergaming balance based training system, the control group (n=12) underwent a conventional balance training. All objective outcomes were measured before intervention and the day after completion of training program. Postural stability was assessed using the quiet standing test, dynamic balance was assessed using limits of stability (LOS) and functional balance (FBT) tests. RESULTS: After training, participants in both groups showed significantly better results in static balance performance. However, only exergaming training significantly improved LOS performance (higher values of Range of forward lean (p = 0.039, dz = 0.67) and leaning rate (p=0.007, dz=0.96). Also FBT test improved significantly only in experimental group (decrease in time to target hit (p=0.02, dz=0.76) and significant increase of average COP velocity (p=0.008, dz=0.93). CONCLUSION: This study found that exergaming training created for patients with PD enhanced static and dynamic balance whereas conventional balance training improved static balance. Posturography is sensitive enough to reveal differential effects of training for both groups. These findings support the inclusion of our exergaming training in the exercise program for participants with PD.

The Effects of Exergaming Training on Balance in Healthy Elderly Women-A Pilot Study.

Our aim was to observe, through objective testing using an assessment module incorporated in a new exergaming system, whether elderly people's static and functional balance is improved by a balance exergaming training program based on movements performed in everyday life. Thirteen healthy elderly women participated in 12 sessions of balance-based exergaming training (three times a week, 30 min per session). All objective outcomes, the quiet standing test, functional balance test (FBT), and limit of stability (LOS) test, were measured on three occasions: before intervention, after six training sessions, and after the completion of the four-week program. The results showed a significant improvement in LOS performance after the intervention. In FBT, participants exhibited a significant decrease (p < 0.01; Kendall's W = 0.5) in the average time to target hit after six trainings. The average center of pressure velocity increased after six and 12 sessions, however did not reach significance (p = 0.053); nevertheless the size of the effect was large (ηp2 = 0.22). The parameters of the quiet standing test were not significantly affected by the training. The results support the need for more definite and objective studies assessing exergaming for balance in elderly.

Fall-related measures in elderly individuals and Parkinson's disease subjects.

Falls pose a serious problem in elderly and clinical populations. Most often, they lead to a loss of mobility and independence. They might also be an indirect cause of death. The aim of this study was to determine an objective predictor of the fear of falling and falls in elderly subjects (ESs) and Parkinson's disease (PD) subjects. Thirty-two ESs were examined in this study, of whom sixteen were diagnosed with PD. The testing procedures comprised force plate measurements (limit of stability test-LOS test) and clinical tests (Berg Balance Scale, Functional Reach Test, Timed Up and Go test, Tinetti test). The Falls Efficacy Scale International (FES-I) was used to evaluate the fear of falling. The range of the maximum forward lean was normalized to the length from the ankle joint to the head of the first metatarsal bone and was named the functional forward stability indicator (FFSI). The FFSI, derived from the LOS test, allowed us to demonstrate the real deficit in functional stability and individual safety margins. Moreover, the FFSI was highly correlated with the FES-I score and almost all clinical test results in elderly subjects (r>0,6; p<0.05). In PD subjects, the FFSI was poorly correlated with the fear of falling, the BBS score and the FR distance; however, a high correlation with the Tinetii test (r>0,6, p<0.05) was noted. The PD subjects presented a different balance strategy when close to their stability limits, which was also reflected in the lower values of sample entropy (t = (-2.40); p<0.05; d = 0.87). The FFSI might be a good predictor of the fear of falling in the group of elderly people. Additionally, the FFSI allows us to show real balance deficits both in PD subjects and in their healthy peers without the need for a reference group and norms. In conclusion, it is postulated that the popular clinical assessments of postural balance in PD subjects should be accompanied by reliable posturography measurements.

Plantar pressure distribution and spatiotemporal gait parameters after the radial shock wave therapy in patients with chronic plantar fasciitis.

Radial shock wave therapy (RSWT) has been recommended as an appropriate, safe and effective method in the treatment of chronic plantar fasciitis (PF). The main purpose of this study was to examine how RSWT affects gait parameters. This study included 23 patients with unilateral, chronic PF. RSWT were administered in 5 interventions, during a consecutive 3-week period. Objective kinetic (force distribution under the forefoot, midfoot, rearfoot) and spatiotemporal parameters (cadence, step length, stance phase duration) during treadmill walking at, preferred" speed were evaluated on. 4 sessions: before therapy, immediately after (primary endpoint), 3 and 6 weeks after therapy. The mean reduction in the reported pain when taking first steps in the morning from baseline to the primary endpoint, 3- and 6-weeks post procedure was 42.7%, 50.1% and 66.9% respectively. Similar reduction was seen in the reported pain during walking. After the therapy during gait at the preferred speed patients had a significantly higher force beneath the rearfoot and forefoot of both limbs. Force beneath the midfoot was not significantly affected by treatment. The step length in both limbs increased by 3.3-3.6 cm after RSWT. After the therapy stance phase duration in symptomatic foot was longer by 7% and it slightly decreased until POST-6wk. Similar changes were seen in an asymptomatic limb. The spatiotemporal and kinetic results indicate that RSWT therapy induces changes in patient's gait structure and alter regional loading in the affected foot.

Standards of Virtual Reality Application in Balance Training Programs in Clinical Practice: A Systematic Review.

OBJECTIVE: To determine the effect of virtual reality (VR) games on improving balance in different groups of neurological patients with a particular focus on the study quality and to determine the gold standard in VR training in these groups. MATERIALS AND METHODS: A systematic review of controlled trials published between January 2009 and December 2017 was conducted. The PubMed, SCOPUS, SPORTDiscus, and Medline databases were searched. Studies involved patients with stroke or Parkinson's disease or children with cerebral palsy. The Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality of the included studies. RESULTS: A total of 20 studies met the inclusion criteria. The PEDro scores ranged from 4 to 8 points. Analysis of the rehabilitation programs revealed a very large discrepancy in the planned volume of exercises in different subgroups of patients. CONCLUSIONS: Overall, the comparison of VR interventions between conventional rehabilitation and no intervention exhibited significantly better results. However, these results should be interpreted with great caution due to the large diversity of the systems, games, and training volume used in the VR therapy. In all included studies, only several articles included objective methods to assess the effect of VR. In addition, most of the articles showed a high risk of bias, such as a lack of randomization and blinding or a small sample size. That is why further well-designed randomized control trials are required to evaluate the influence of VR on balance in different groups of neurological patients.

Effects of 8-Week Complex Balance Training in Young Alpine Skiers: A Pilot Study.

OBJECTIVES: The purpose of this study was to determine the effects of an 8-week complex balance training program on dynamic balance in skiers according to the new balance training protocol. DESIGN: Intervention study, comprising 8 weeks of core stability, plyometric, balance, and stretching exercises. PARTICIPANTS: Ten young skiers volunteered to take part in this study (average age, height, and body mass were 16,44 +/- 1,07 years, 172,76+/-8,84 cm, and 67,4 11,44 kg, respectively (mean +/- SD)). MAIN OUTCOME MEASURES: Subjects' dynamic balance performance was assessed and retested after training completion with the use of dynamic balance measurement within the Optojump Next System. RESULTS: The results of 8-week complex balance training showed significant improvements for jump height (H) and flight time (FT) for the left leg and jumping area in both legs. CONCLUSION: The complex balance training program improved parameters of dynamic stability in young skiers and led to decreased asymmetry between lower extremities.

A posturographic procedure assessing balance disorders in Parkinson's disease: a systematic review.

Postural instability is common in Parkinson's disease (PD), often contributing to falls, injuries, and reduced mobility. In the clinical setting, balance disorder is commonly diagnosed using clinical tests and balance scales, but it is suggested that the most sensitive measurement is the force platform. The aim of this systematic review was to summarize the methods and various posturographic procedures used to assess the body balance and gait in PD. A systematic review was conducted of papers published from 2000 to 2017. Databases searched were PubMed and EBSCO. Studies must have involved patients with PD, used force platform or motion analysis system as a measurement tool, and described posturographic procedure. The Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality of the included studies. A total of 32 studies met the inclusion criteria. The PEDro scores ranged from 5 to 7 points. The analysis of the objective methods assessing balance disorders revealed a large discrepancy in the duration and procedures of measurements. The number of repetitions of each trial fluctuated between 1 and 8, and the duration of a single trial ranged from 10 to 60 seconds. Overall, there are many scales and tests used to assess the balance disorders and disabilities of people with PD. Although in many included studies the authors have used posturography as a method to evaluate the postural instability of PD patients, the results are contradictory. To solve this issue, it is indicated to establish a "gold standard" of procedures of measures of balance.

Balance Training Programs in Athletes - a Systematic Review.

It has become almost routine practice to incorporate balance exercises into training programs for athletes from different sports. However, the type of training that is most efficient remains unclear, as well as the frequency, intensity and duration of the exercise that would be most beneficial have not yet been determined. The following review is based on papers that were found through computerized searches of PubMed and SportDiscus from 2000 to 2016. Articles related to balance training, testing, and injury prevention in young healthy athletes were considered. Based on a Boolean search strategy the independent researchers performed a literature review. A total of 2395 articles were evaluated, yet only 50 studies met the inclusion criteria. In most of the reviewed articles, balance training has proven to be an effective tool for the improvement of postural control. It is difficult to establish one model of training that would be appropriate for each sport discipline, including its characteristics and demands. The main aim of this review was to identify a training protocol based on most commonly used interventions that led to improvements in balance. Our choice was specifically established on the assessment of the effects of balance training on postural control and injury prevention as well as balance training methods. The analyses including papers in which training protocols demonstrated positive effects on balance performance suggest that an efficient training protocol should last for 8 weeks, with a frequency of two training sessions per week, and a single training session of 45 min. This standard was established based on 36 reviewed studies.