Assessment of dental student posture in two seating conditions using RULA methodology – a pilot study A dental stool with chest support reduces lower back muscle activation Passive rotary dynamic sitting at the workplace by office-workers with lumbar pain: a randomized multicenter study. A wheelchair cushion designed to redistribute sites of sitting pressure. Neuromuscular electrical stimulation and an ottoman-type seat effectively improve popliteal venous flow in a sitting position. The relationship between pressure ulcer incidence and buttock-seat cushion interface pressure in at-risk elderly wheelchair users. Reducing risk of falling in older people discharged from hospital: a randomized controlled trial comparing seated exercises, weight-bearing exercises, and social visits. Effects of seated whole-body vibration on postural control of the trunk during unstable seated balance.
Objectives To assess dental students ' posture on two different seats in order to determine if one seat predisposes to a difference in working posture . Design A between-subject experimental design was selected . Setting The study was undertaken at the University of Birmingham School of Dentistry in 2006 . Subjects ( material s ) and methods Sixty second year dental students at the University of Birmingham who were attending their fi rst classes in the phantom head laboratory were r and omly selected and allocated to two different seats ( 30 Bambach Saddle Seats and 30 conventional seats ) . Students were trained in the use of the seats . After ten weeks , the students were observed , photographs were taken by the research er and these were assessed using Rapid Upper Limb Assessment ( RULA ) . Main outcome measures The posture of the students was assessed using the RULA . Each student was given a risk score . A Mann Whitney test was used for statistical analysis . Results The results indicated that the students using the conventional seat recorded signifi cantly higher risk scores ( p < 0.05 ) when compared with the students using Bambach Saddle Seat , suggesting an improvement in posture when using the Bambach Saddle Seat . Conclusion RULA has identifi ed that dental students using a Bambach Saddle Seat were able to maintain an acceptable working posture during simulated dental treatment and this seating may reduce the development of work-related musculoskeletal disorders Activation of back musculature during work tasks leads to fatigue and potential injury . This is especially prevalent in dentists who perform much of their work from a seated position . We examined the use of an ergonomic dental stool with mid-sternum chest support for reducing lower back muscle activation . Electromyography of lower back extensors was assessed from 30 dental students for 20 s during three conditions in r and om order : ( a ) sitting upright at 90 ° of hip flexion on a st and ard stool , ( b ) leaning forward at 80 ° of hip flexion on a st and ard stool , and ( c ) leaning forward at 80 ° of hip flexion while sitting on an ergonomic stool . Muscular activity of the back extensors was reduced when using the ergonomic stool compared to the st and ard stool , by 33–50 % ( p < 0.01 ) . This suggests a potential musculoskeletal benefit with use of a dental stool with mid-sternum chest support BACKGROUND CONTEXT It is generally recognized that long periods of sitting can either cause or aggravate lumbar pain . A new , ergonomically design ed chair has a fixed backrest and a motor-driven seat with a horizontal rotary movement in alternating left-right cycles . PURPOSE The objective of this study is to prove superiority of the new technique of passive rotary dynamic sitting for subjects working in a sedentary occupation and suffering from lumbar pain . STUDY DESIGN / SETTING A r and omized , double-blind , multicenter , two-armed study was performed using a parallel group design . PATIENT SAMPLE 280 persons suffering from lumbar pain were matched pairwise and r and omized en bloc . OUTCOME MEASURES The first and second primary endpoints target criteria were the vali date d German version of the Oswestry Disability Index ( ODI ) and the number of days of absence from work ( DA ) attributable to lumbar pain , each based on a blinded 2-year follow-up observation after r and omization of the subjects . METHODS After inclusion in the study anonymization , the prob and s were r and omized to receive either an office chair with a motor-driven seat performing a horizontal rotary movement or a chair of the same design without the rotary seat movement . Before delivery of the chairs , 23 prob and s ( 8.2 % ) withdrew their consent to inclusion in the study without stating reasons . From 12 of the remaining matching partners , 23 new pairs were created at r and om , and the study commenced with 124 pairs . RESULTS A further 27 prob and s ( 9.6 % ) were lost to follow-up during the period up to the final consultation . This made it possible to observe the primary endpoint in 82.5 % of the prob and s. The median ODI in both groups was 53 ( 95 % confidence interval for median difference:-1.5 to 0.5 ; p=.59 ) . Median DA in both groups was 0 ( 95 % confidence interval for median difference:-infinity-+infinity ; p=1.00 ) . CONCLUSIONS Under the test conditions used in this study , passive rotary dynamic sitting was not superior to sitting in a high- quality , ergonomically design ed chair not equipped with a micro-rotation function in patients suffering from lumbar pain OBJECTIVES Despite the diversity of wheelchair cushions currently in clinical use , pressure on bony prominences continues to be a major problem for wheelchair-bound patients , and the incidence of pressure ulcers remains high . No static surface has been reported to reduce resting pressure under the ischial tuberosities to below that of capillary pressure , which may well be the threshold for inducing tissue damage . An entirely new form of seating was design ed to decrease absolute pressure using a prosthetic fitting technique analogous to a below-the-knee prosthesis . DESIGN A repeated measures r and omized design was used to test differences between the experimental ( TCS ) and three other st and ard cushions . SETTING A Veterans Medical Center outpatient service . PATIENTS Wheelchair-bound volunteer subjects , n = 47 , were selected who weighed more than 60 kg . MAIN OUTCOME MEASURES Pressures were measured by a st and ard air pressure pad and also by a computer-linked array of pressure transducers . The grid was st and ardized and used to generate topographic maps for each site over time . These data were used to measure the seating interface pressures . RESULTS There was a significant main effect of cushion over site , F = 131 for left ischial tuberosity . Pressure were lowest while patients sat on the experimental seat and differences were significant at all time points . Using 1psi as presumed capillary pressure , frequency of success at achieving this pressure threshold was greatest for the experimental seat , p < .001 . This difference persisted throughout the 30 minutes of testing . CONCLUSIONS A computerized pressure grid was developed that allowed evaluation of anatomically localized pressures . The prosthetically design ed TCS displays lower seating pressures than any other cushion tested . Consistent and sustained pressures were below the postulated threshold for tissue damage The aim of this study was to examine the effects of the sitting posture on the lower limb venous flow and to explore the beneficial effects of  neuromuscular electrical stimulation ( NMES )  and an ottoman-type seat on the venous flow . Healthy adult volunteers without a history of lower limb surgery or thromboembolism were recruited , and the flow velocity , cross-sectional area , and flow volume of the popliteal vein were measured using Doppler ultrasound . A posture change from the prone position to the sitting position on the ottoman-type seat decreased the flow velocity and increased the cross-sectional area of the popliteal vein , and the flow volume was not altered over 120 min . The flow velocity was further decreased , and the cross-sectional area was further increased by subjects sitting on a regular driving seat when compared with the values obtained with an ottoman-type seat . The popliteal flow velocity in the NMES leg was significantly higher than in the non-NMES leg throughout the 120-min testing in the sitting position , but no difference in the cross-sectional area was found between the NMES and the non-NMES legs . Thus lower limb venous stasis elicited by the sitting posture was improved by the ottoman-type seat and NMES OBJECTIVE To investigate the relation between pressure ulcer incidence and buttock-wheelchair seat cushion interface pressure measurements . DESIGN Secondary analysis of data from a r and omized clinical trial . SETTING Skilled nursing facility . PATIENTS Thirty-two elderly patients ( age , > or = 65 yr ) , with Braden score < or = 18 and Braden mobility and activity subscale score < or = 5 , who used wheelchairs > or = 6 hr/d , were free of existing sitting-induced pressure ulcers , and weighed < or = 250 lb . INTERVENTIONS Generic foam seat cushion or pressure-reducing seat cushion . MAIN OUTCOME MEASURES The incidence of sitting-induced pressure ulcers over a 1- to 12-month period was compared with pressure measured between patients ' buttocks and wheelchair seat cushions . A flexible pad with a 15 x 15 pressure sensor array was used to measure interface pressure . RESULTS Interface pressure measured on wheelchair seat cushions was higher ( p < or = .01 for both peak pressure and average of highest 4 pressures ) for patients who developed sitting-acquired pressure ulcers compared with those patients who did not . CONCLUSIONS Results indicated that higher interface pressure measurements are associated with a higher incidence of sitting-acquired pressure ulcers for high-risk elderly people who use wheelchairs OBJECTIVE To compare the efficacy of seated exercises and weight-bearing ( WB ) exercises with social visits on fall risk factors  in older people recently discharged from hospital . DESIGN Twelve-week r and omized , controlled trial . SETTING Home-based exercises . PARTICIPANTS Subjects ( N=180 ) aged 65 and older , recently discharged from hospital . INTERVENTIONS Seated exercises ( n=60 ) , WB exercises ( n=60 ) , and social visits ( n=60 ) . MAIN OUTCOME MEASURES Primary outcome factors were Physiological Profile Assessment ( PPA ) fall risk score , and balance while st and ing ( Coordinated Stability and Maximal Balance Range tests ) . Secondary outcomes included the component parts of the PPA and other physical and psychosocial measures . RESULTS Subjects were tested at baseline and at completion of the intervention period . After 12 weeks of interventions , subjects in the WB exercise group had significantly better performance than the social visit group on the following : PPA score ( P=.048 ) , Coordinated Stability ( P<.001 ) , Maximal Balance Range ( P=.019 ) ; body sway on floor with eyes closed ( P=.017 ) ; and finger-press reaction time ( P=.007 ) tests . The seated exercise group performed better than the social visit group in PPA score ( P=.019 ) but for no other outcome factor . The seated exercise group had the highest rate of musculoskeletal soreness . CONCLUSIONS In older people recently discharged from the hospital , both exercise programs reduced fall risk score in older people . The WB exercises led to additional beneficial impacts for controlled leaning , reaction time , and caused less musculoskeletal soreness than the seated exercises BACKGROUND Low back disorders and their prevention is of great importance for companies and their employees . Whole-body vibration is thought to be a risk factor for low back disorders , but the neuromuscular , biomechanical , and /or physiological mechanisms responsible for this increased risk are unclear . The purpose of this study was to measure the acute effect of seated whole-body vibration on the postural control of the trunk during unstable seated balance . METHODS Twenty-one healthy subjects ( age : 23 years ( SD 4 years ) ) were tested on a wobble chair design ed to measure trunk postural control . Measurements of kinematic variance and non-linear stability control were based on seat angle before and after 30 min of seated whole-body vibration ( b and width=2 - 20 Hz , root-mean-squared amplitude=1.15m/s(2 ) ) . FINDINGS All measures of kinematic variance of unstable seated balance increased ( P<0.05 ) after vibration including : ellipse area ( 35.5 % ) , root-mean-squared radial lean angle ( 17.9 % ) , and path length ( 12.2 % ) . Measures of non-linear stability control also increased ( P<0.05 ) including Lyapunov exponent ( 8.78 % ) , stability diffusion analysis ( 1.95 % ) , and Hurst rescaled range analysis ( 5.2 % ) . INTERPRETATION Whole-body vibration impaired postural control of the trunk as evidence d by the increase in kinematic variance and non-linear stability control measures during unstable sitting . These findings imply an impairment in spinal stability and a mechanism by which vibration may increase low back injury risk . Future work should investigate the effects of whole-body vibration on the anatomical and neuromuscular components that contribute to spinal stability
The two eligible studies for this review provide moderate evidence that saddle seats provided lower ergonomic risk than conventional seats in the examined population of dental students
OBJECTIVE This study aim ed to verify whether the saddle seat provides lower ergonomic risk than conventional seats in dentistry .