On the role of ageing and musculoskeletal pain on dynamic balance in manual workers

The purpose of this study was to explore the interacting effects of age and musculoskeletal pain on balance in manual workers. Ninety male manual workers aged 51–72 yr were recruited and stratified according to lower extremity musculoskeletal pain intensity (pain/no pain) and work status (working/retired). The five-repetition sit-to-stand (STS) test was used to assess lower extremity function including completion time, stand time, sit time and dynamic rate of force development both in the upwards (RFD_up) and downwards moving phase (RFD_down). Dynamic balance was expressed as the range, velocity, standard deviation (SD), maximum Lyapunov Exponent and sample entropy of centre of pressure displacement in the anterior-posterior and medial-lateral direction, as well as free moment during the STS test. Except for higher age, no marked differences were seen between working and retired participants. Both age and musculoskeletal pain were negatively associated with motor function. Age × pain interactions showed that completion time, stand time, RFD_up and RFD_down were negatively associated with age for participants without pain, but positively for those with pain. Similar findings were seen for dynamic balance. These findings indicate that the effects of lower extremity musculoskeletal pain on lower extremity function and dynamic balance are age dependent.     

The influence of adipose tissue location on postural control

A growing body of evidence suggests, that excessive body weight is inseparably connected with postural instability. In none of previous studies, body weight distribution has been considered as a factor, which may affect results of a static posturography. The purpose of the present study is to quantify some center of foot pressure (COP) characteristics in 40 obese women with android type of obesity (waist-to-hip ratio - WHR ≥ 0.85, BMI: 37.5 ± 5.4) and 40 obese women with gynoid type of obesity (WHR < 0.85, BMI: 36.9 ± 5.1). Variables of postural sway were acquired while subjects were standing quietly on a force plate with eyes open and closed. Both in the sagittal and frontal plane sway range, average velocity, and maximal velocity of COP were calculated. Moreover, the total average velocity and total maximal velocity of the COP displacement were computed.Women with abdominal obesity showed a larger sway range in the anterior-posterior plane with eyes open (p < 0.0282) and eyes closed conditions (p < 0.0115) and a greater maximal COP velocity to compare with subjects with gynoidal obese type (p < 0.0112) with eyes closed condition.The postural stability in obese women from the biomechanical point of view is strongly dependent on body distribution. Women with the abdominal obesity type may be exposed to a greater risk of postural instability as compare to women with gynoid fat distribution.     

Intraobserver reliability of posturography in patients with vestibular neuritis

The aim of the study was to establish the intraobserver reliability of a posturographic method in patients (n?=?34) with vestibular neuritis. Intraclass correlation coefficients (relative reliability) for all parameters and test positions (ALL_mean) ranged from 0.71 (95% CI: 0.41–0.85) to 0.92 (95% CI: 0.84–0.96). Absolute reliability (coefficient of variation) ranged between 3.1% (95% CI: 2.60–8.67) and 42.3% (95% CI: 40.7–74.5). Reliability of single test positions is much lower. The posturographic system showed good relative and satisfactory absolute intraobserver reliability for ALL_mean.     

Effects of five days of bed rest with intermittent centrifugation on neurovestibular function

Objectives:

We tested whether intermittent short-radius centrifugation was effective for mitigating alteration in balance and gait following bed rest.

Methods:

Ten male subjects were exposed to 5 days of 6° head-down tilt bed rest with: (a) no countermeasure; (b) daily 1-g centrifugation for a continuous 30-min period; and (c) daily 1-g centrifugation for six periods of 5 min. During and after the bed rest, subjects were asked to scale the severity of neurovestibular symptoms that followed centrifugation or 80º head-up tilt. Following the bed rest, equilibrium scores were derived from anterior-posterior sway while standing on a foam pad with the eyes open or closed while making pitch head movements, and gait was evaluated by grading subjects’ performance during various locomotion tasks.

Results:

At the beginning of bed rest, one single 30-min period of centrifugation induced more severe neurovestibular symptoms than six periods of 5-min centrifugation. After bed rest, although equilibrium scores and gait performance were not significantly altered, subjects felt less neurovestibular dysfunction with orthostatic stress when centrifugation was used.

Conclusion:

Centrifugation was effective at reducing the severity of neurovestibular symptoms after bed rest, but this decrease was not different between one or multiple daily sessions.     

Balance study in asymptomatic subjects: Determination of significant variables and reference patterns to improve clinical application

Postural control is essential when carrying out everyday activities and its possible disorders have a very significant impact on personal autonomy. To provide the means to accurately measure postural control in the clinical environment, this study checks and discusses the suitability of procedures for a new balance assessment system with a stabilometric platform (MoveHuman-Dyna © UZ-IDERGO), which meets the criteria of clinical stabilometric standardisation established by the International Society for Posture and Gait Research (ISPGR) at the Bologna meeting (2009). The study was applied to a sample of 30 healthy volunteers (12 women, 18 men) aged between 18 and 30 years. A total of six balance tests were performed: four variations of the Romberg test, one test for a study of the limits of stability (LoS) and one test for rhythmic weight shift (RWS). Analysis of the results confirms that the variables assessed yielded similar values to other studies, the consistency of values between tests was checked, and preliminary reference values were obtained for asymptomatic subjects. We propose the following variables as the most significant for balance diagnosis: CoP mean speed, RMS, Range of CoP displacement and area. As a result of the study, the system is considered of interest in the medical/legal and forensic settings to assess the balance control and degree of collaboration during the tests.     

Wearing shoes increasing dorsiflexion improves short-term but not long-term balance control in young healthy adults

Wearing sport shoes inducing ankle dorsiflexion has been shown to alter the biomechanical specificities of the stretched muscles. The possible effect over the short and long term upon the sensorial capacities induced by such stretching has not been addressed yet. Fourteen healthy individuals were involved to assess the proprioceptive repercussion and their effects upon postural control strategies. Postural control and proprioceptive assessment were measured twice: when receiving sport shoes inducing ankle dorsiflexion and 18 days later. Proprioceptive effects were assessed using an ad-hoc device through which the seated and blindfolded subjects were required to reposition their feet in a starting position after the ankles were passively displaced to dorsiflexed and plantarflexed positions. Center-of-gravity horizontal displacements (CG_v), estimated from center-of-pressure (CP) displacements, and CP–CG_v displacements were measured through a force platform during upright quiet stance maintenance. The initial session was recorded with the subjects barefoot and wearing the shoes with a set of chocks with 0° (horizontal) and −5° (dorsiflexion) tilting angles. The second session included only barefoot performance in horizontal and dorsiflexion conditions. Dorsiflexion had no immediate effect on the postural control strategies along the anteroposterior axis. In contrast, barefoot or wearing shoes, stability was increased along the mediolateral axis during the dorsiflexion conditions. No ankle proprioceptive or postural change was observed after wearing the shoes for 18 days. Wearing dorsiflexion sport shoes induces short-term effects probably by inducing a backward tilt of the pelvis. A muscular adaptation likely prevents this effect from being prolonged.     

Bridging the gap between temporomandibular disorders,static balance impairment and cervicogenic dizziness: Posturographic and clinical outcomes

Several studies have investigated the possible influence of temporomandibular disorders (TMD) on body posture and whether cervical spine disorders, such as cervicogenic dizziness (CGD) could play an additional role in affecting static balance. The purpose of this study was to analyze static postural behavior by means of static posturography, in patients affected by either TMD or CGD alone or by both conditions, and to compare findings with a group of healthy subjects. Significant changes in posturographic parameters were found among the three groups of patients and when compared with controls. When the three study groups were compared to each other, subjects affected by a combination of TMD and CGD showed worse postural performances with respect to subjects affected by CGD or TMD alone. Correlations with self-perceived dizziness, anxiety, depression and jaw functionality, investigated by means of validated questionnaires, were found among all patient groups. These results provide new evidences for the presence of static balance alterations in patients suffering from TMD with and without associated cervical spine impairment, by using a reliable diagnostic technique. Further studies are needed in order to identify any causal relation between these two disorders.     

生理节律与日常活动对人体疲劳程度的影响

目的:研究生理节律和日常活动分别对人体疲劳程度的影响大小。方法:选取某校7名大学生志愿者,在军训期间对每日军训科目严格限制条件下进行该实验,以闪光临界融合频率、心率变异性、反应时、静态姿势图TLX-NASA量表评分作为指标,对每天分别在训练前和训练后疲劳程度的大小进行测量,以这些指标描述训练前后的疲劳程度。结果:反应时降低(0.60±0.09)、反应正确率提高(0.97±0.03);闪光临界光融合频率升高(40.84±2.14);心率变异性TP(3076.60±382.08)降低、心率变异性SDNN(55.28±16.85)降低;静态姿势图晃动减少,中低频率段(0.15±0.01)、前后方向重心变位(7.92±0.63),TLX-NASA量表评分降低(30.47±10.23)。以上差异均具有统计学意义(P<0.05)。结论:生理节律相对于日常活动对机体的疲劳状态有更大的影响。