The Scottish national LifeCurve™ survey: costs of functional decline, opportunities to achieve early intervention to support well-being in later life, and meaningfulness of the LifeCurve™.

OBJECTIVES: The aim of the Scottish AHP LifeCurve™ survey was to gather a snapshot of where people are on their LifeCurve™ when receiving allied health professions (AHP) services and to understand the cost consequence of intervening 'late' in the ageing trajectory. The objectives were to promote discussion around preventing functional decline, support innovation in service delivery, and facilitate broader engagement with individuals, communities, and wider environments for improving health and well-being in later life. In addition, subsequent learning could help address the increasing resource gap between the demand and capacity across health and social care. STUDY DESIGN: The survey was paper-based in the form of a printed booklet, which contained the 15 activities of daily living (ADL) and instrumental ADL (IADL) which comprise the LifeCurve™ with additional lifestyle questions and information about the member of staff and service the participant was seen in, including their Community Health Index (CHI) number. The survey questions and booklet layout were tested over a five-month period with AHPs and people receiving AHP services. Liaison with national health literacy colleagues and lead speech and language therapists ensured that the survey material was accessible to a wide range of people. In addition, the survey could be made available in alternative formats, on request. METHODS: Agreement to undertake the national survey was obtained in November 2016 by all AHP directors and associate directors who appointed communication support leads in their area who would support implementation at all stages at a local level. All materials relating to the survey were published on a dedicated area of a community of practice to support awareness and training during the preimplementation phase. AHPs working in adult services were asked to complete a survey with a minimum of two people they would 'typically' see in their service during a two-week period in May 2017, with the exclusion of people who were too unwell to participate, children and young people under 16 years, and adults with incapacity and without a guardianship arrangement in place. Approval was gained from the Public Benefit Privacy Panel to link the survey data to participants' health service usage using their CHI number. Completed forms were returned to the University of Strathclyde for entry into an encrypted electronic database using a double data entry process and were allocated a unique identifier. The unique identifier and CHI numbers were sent to Information Services Division (ISD), and then, the CHI numbers were deleted from the encrypted database. ISD sent the linked health data to the Scottish Government Analytical Services Division, which thus produced a full encrypted and anonymised database. RESULTS: The data explain what stages on the LifeCurve™ AHPs are intervening, and the matched data provide associated healthcare costs at each stage. Due to poor or missing data in the AHP/Service section, only 60% (n = 8261) of the total completed surveys were able to be matched with health service usage records. These data show that whilst AHPs are seeing people at each of the 15 ADL/IADL stages on the LifeCurve™, interventions fell into three groups where 25% of people where seen at the 'precurve' stage, 13% of people at 'mid-curve' (stage number five), and 39% of people at 'late-curve' (stages 10 to 13). The healthcare cost usage of these participants increased the further along the LifeCurve™ a person moves, with an average annual cost of £2700 at 'precurve' rising to £12,330 at 'late-curve' in 2016-2017. The results indicate that different services and professions are represented at each of these three points. So, for example, as might be expected, outpatient (especially musculoskeletal) services were seen more often at the 'precurve' stage, and in-patient and community rehabilitation, services were seen more often at the 'late-curve' stages; diagnostic radiographers and orthoptists saw people at the 'early-curve' stages, dieticians and podiatrists saw people at the 'mid-curve' stage, whilst physiotherapists, speech and language therapists, and occupational therapists saw people at the 'late-curve' stages. Data analysis showed this pattern is different for people receiving mental health services and, so, their data were removed and will be analysed and reported separately. CONCLUSIONS: It is clear from the results that healthcare costs increased as participants moved down LifeCurve™ stages, that is, as their levels of functional decline increase. It is also clear that AHPs are intervening late in a person's functional decline with associated limitations on changing their ageing trajectory. The cost consequence of this is significant - moving someone from 'late- to mid-curve' could save £3200 per person per annum. However, those AHPs typically associated with reabling approaches and rehabilitation, which have greatest potential to change ageing trajectories, were not represented at the 'mid-curve' stage (e.g., physiotherapists, occupational therapists). Therefore, we must find places to have conversations with people to inform them that functional decline is malleable and not inevitable purely by virtue of chronological age and provide education and support to prevent or reverse functional decline and collaborate around strategic planning and commissioning to offer different options that support an optimum LifeCurve™.

The Past and Future of Clinical Biomechanics: Time to deliver on the legacy of pioneers such as Professor John P. Paul (1927-2013).

This editorial pays tribute to the work of Professor John P. Paul and his team at the University of Strathclyde in the 1960s and '70s, and subsequently by the Strathclyde Rehabilitation Engineering Group, as featured in the journal Medical Engineering & Physics. It also includes a consideration of the nature of full biomechanical analysis of movement and how it can be mathematically modelled and physically recorded, the different approaches taken by Paul's and Winter's groups, respectively, and what a full biomechanical model should include in the future. The article also attempts to signpost the reader to future developments in the field, and how the techniques pioneered by Paul in the 1960s may influence Clinical Biomechanics and Rehabilitation in the years to come.

Gait stability in response to platform, belt, and sensory perturbations in young and older adults.

Perturbation-based gait assessment has been used to quantify gait stability in older adults. However, knowledge on which perturbation type is most suitable to identify poor gait stability is lacking. We evaluated the effects of ipsi- and contra-lateral sway, belt acceleration and deceleration, and visual and auditory perturbations on medio-lateral (ML) and anterior-posterior (AP) margins of stability (MoS) in young and older adults. We aimed to evaluate (1) which perturbation type disturbed the gait pattern substantially, (2) how participants recovered, and (3) whether recovery responses could discriminate between young and older adults. Nine young (25.1 ± 3.4 years) and nine older (70.1 ± 7.6 years) adults walked on the CAREN Extended (Motek BV, The Netherlands). The perturbation effect was quantified by deviation in MoS over six post-perturbation steps compared to baseline walking. Contra-lateral sway and deceleration perturbations resulted in the largest ML (1.9-4 times larger than other types) and AP (1.6-5.6 times larger than other types) perturbation effects, respectively. After both perturbation types, participants increased MoS by taking wider, shorter, and faster steps. No differences between young and older adults were found. We suggest to evaluate the potential of using contra-lateral sway and deceleration perturbations for fall risk identification by including both healthy and frail older adults. Graphical abstract Margins of stability during steady state (left) and perturbed (right) gait to quantify reactive gait stability in response to various perturbation types in young and older adults.

Measuring movement fluency during the sit-to-walk task.

BACKGROUND: Restoring movement fluency is a key focus for physical rehabilitation; it's measurement, however, lacks objectivity. The purpose of this study was to find whether measurable movement fluency variables differed between groups of adults with different movement abilities whilst performing the sit-to-walk (STW) movement. The movement fluency variables were: (1) hesitation during movement (reduction in forward velocity of the centre of mass; CoM), (2) coordination (percentage of temporal overlap of joint rotations) and (3) smoothness (number of inflections in the CoM jerk signal). METHODS: Kinematic data previously collected for another study were extracted for three groups: older adults (n=18), older adults at risk of falling (OARF, n=18), and younger adults (n=20). Each subject performed the STW movement freely while a motion analysis system tracked 11 body segments. The fluency variables were derived from the processed kinematic data and tested for group variation using analysis of variance. FINDINGS: All three variables showed statistically significant differences among the groups. Hesitation (F=15.11, p<0.001) was greatest in the OARF 47.5% (SD 18.0), compared to older adults 30.3% (SD 15.9) and younger adults 20.8% (SD 11.4). Co-ordination (F=44.88, p<0.001) was lowest for the OARF (6.93%, SD 10.99) compared to both the young (31.21%, SD 5.48) and old (26.24%, SD 5.84). Smoothness (F=35.96, p<0.001) was best in the younger adults, 18.3 (SD 5.2) inflections, compared to the old, 42.5 (SD 11.5) and OARF, 44.25 (SD 7.29). INTERPRETATION: Hesitation, co-ordination and smoothness may be valid indicators of movement fluency in adults, with important consequences for research and clinical practice.

A purpose-built dynamometer to objectively measure static and dynamic knee torque.

This paper reports the development of a purpose-built knee dynamometer (PBKD) to evaluate passive range of motion (ROM) and isometric muscle strength measurements of the knee. The PBKD uses a TorqSense rotary torque transducer and objectively measures isometric knee muscle strength in a valid and reliable manner and passive resistance to motion through range. The device and all associated instrumentation underwent dynamic and static calibration to ensure consistent and accurate measurements were obtained in terms of knee joint angular position, passive torque measures, and isometric torque measures. Eleven healthy male participants performed a knee flexion and extension task designed to evaluate knee function. The validation of the PBKD entailed measuring the consistency of measurement and accuracy of measurement. Accuracy of the PBKD was determined by comparing peak isometric muscle strength measurements against a KIN-COM machine. No significant differences were observed both passively and isometrically between cycles and between trials. This device can have widespread applications within the rehabilitation and clinical environment and could be used as a functional outcome measuring tool to distinguish pathological from non-pathological knees. The presented preliminary results indicate that reliable and accurate measurements of knee ROM and muscle strength can be obtained.

Visualisation of biomechanical data to assist therapeutic rehabilitation.

PURPOSE: The biomechanics community have to date had limited success in communicating complex biomechanical data and analyses outside of their field. The authors have created an innovative prototype software tool to visualise objective dynamic movement data captured from older adults undertaking activities of daily living (ADLs). Evaluation of this tool has shown it to be a successful way of communicating the complexity of older adult mobility data in an accessible manner for non-biomechanical specialists and lay audiences(1,2). METHODS: A software tool was developed, which generates a 3D animated human 'stick figure', on which the biomechanical demands of ADLs are represented visually at the joints as a percentage of each individual's maximum capability using a continuous colour gradient from green at 0%, amber at 50%, through to red at 100% (Figure 1). The tool was evaluated using a qualitative methodology of interviews and focus groups, where older adults and professionals viewed a series of visualisations of dynamic movement data(3). RESULTS AND DISCUSSION: Analysis of focus group discussions facilitated by the visualizations revealed new kinds of dialogues about biomechanical issues. The method of visualising and presenting the data clearly enabled people without training in biomechanics, both professionals and lay older people, to access and interpret the biomechanical information, based on their background, knowledge of a field or their personal experience. Further, the common visual medium enabled the sharing of different insights without recourse to specialist terminology or knowledge. New kinds of dialogues occurred in focus groups between older people and professionals about their experiences, based on real understanding of where the mobility problems were occurring. New dialogues also emerged between professionals from a range of different disciplines, crucial for different aspects of the care, wellbeing or design of the built environment for older people. Neither of these would have been possible using current conventions of presenting biomechanical data. The visualisations also appear to allow a deeper understanding of the issues within professions, both in healthcare and in design. These findings have led to new research with five discrete yet complementary studies covering a range of clinical applications of this method for: i) mobility and exercise advice for the healthy older adult; ii) falls prevention; iii) rehabilitation of total knee replacement; iv) to enhance early mobilisation of acute stroke patients and v) to enhance biomechanical diagnosis and fitting of ankle foot orthoses (AFO) in late stage stroke.

Between-day repeatability of knee kinematics during functional tasks recorded using flexible electrogoniometry.

The objective of this study was to assess the between-day repeatability of knee kinematics during activities of daily living recorded by electrogoniometry. One rater assessed the peak knee angles and knee excursion of 15 subjects during 13 activities twice with an average of 22 days (range 5-31) between the two assessments. The 15 subjects included four patients one year after total knee replacement (TKR) surgery, five patients before TKR surgery and six age-matched controls. Intra-class correlation coefficients and Bland and Altman coefficient of repeatability were derived to analyse the results. Only the most affected leg of the patients and the right leg of the controls were used for analysis. Different measures of repeatability showed different results. Intra-class correlation coefficients were higher than 0.75 for peak values of all functions except sitting down and rising from a standard chair. However, coefficients of repeatability ranged from 5.6 degrees for the loading response in level walking to 39.8 degrees for stepping out of a bath. Both of these values are higher than clinically significant changes seen after total knee surgery. It was concluded that for a single assessment on individual patients, the functional knee motion as performed in this study did not have sufficient repeatability. However, if the measurements are used to assess the average changes before and after surgery in a group of patients, the assessment of knee motion during activities such as level walking, and slope and stair ascending and descending were found to be sufficiently repeatable.

A prospective randomised double-blind study of functional outcome and range of flexion following total knee replacement with the NexGen standard and high flexion components.

Modifications in the design of knee replacements have been proposed in order to maximise flexion. We performed a prospective double-blind randomised controlled trial to compare the functional outcome, including maximum knee flexion, in patients receiving either a standard or a high flexion version of the NexGen legacy posterior stabilised total knee replacement. A total of 56 patients, half of whom received each design, were assessed pre-operatively and at one year after operation using knee scores and analysis of range of movement using electrogoniometry. For both implant designs there was a significant improvement in the function component of the knee scores (p < 0.001) and the maximum range of flexion when walking on the level, ascending and descending a slope or stairs (all p < 0.001), squatting (p = 0.020) and stepping into a bath (p = 0.024). There was no significant difference in outcome, including the maximum knee flexion, between patients receiving the standard and high flexion designs of this implant.

An electromyographical study to investigate the effects of patellar taping on the vastus medialis/vastus lateralis ratio in asymptomatic participants.

It is commonly theorised that patellofemoral pain syndrome (PFPS) is caused by maltracking due to vastus medialis (VM) weakness relative to the vastus lateralis (VL). Despite this being a controversial theory, patellar taping is a commonly used technique that purports to correct this muscle imbalance by increasing the VM/VL ratio. The effects of different forms of taping on vasti muscle activity are still not known. The objective of this study was to investigate the effects of three different types of patellar taping on the VM/VL ratio in asymptomatic university students. Each participant performed a set of four single-legged squats under four separate taping conditions: A) medial, B) lateral, C) neutral, and D) no-tape. The condition sequence was randomised. The main outcome measure was the normalised VM/VL ratio, assessed by using surface electromyography. Secondary outcome measures were the normalised EMG activity of the VM and the VL. A convenience sample of 24 (17 females) students (22 +/- 10 years, M +/- SD) completed this study. The lateral taping condition produced small but significantly greater VM/VL ratios than the medial (p = 0.007) and neutral (p = 0.007) but not the no-tape (p = 0.123) condition. There were no significant differences between the medial, neutral, and no-tape conditions. These results question whether patellar taping can impart a clinically significant effect on the VM/VL ratio. The results of this study cannot be directly extrapolated to a patient population, and further research in the PFPS population is required before clinical recommendations can be made.

The effect of total knee arthroplasty on joint movement during functional activities and joint range of motion with particular regard to higher flexion users.

PURPOSE: To evaluate active and functional knee excursion of patients before and after total knee arthroplasty (TKA) and to determine whether TKA restores quality of life related to functional activities of daily living. METHODS: Electrogoniometry was used to measure the functional movement of the knee during 11 activities of daily living in 50 patients who underwent TKA. These data were compared with the patient's active range of motion and quality-of-life scores. RESULTS: A cut-off point existed between loss and gain in flexion at between 90 and 95 degrees of preoperative active flexion. Two thirds of patients had preoperative flexion of more than 90 degrees, 83% of them had reduced flexion postoperatively. The remaining one third had preoperative flexion of 90 degrees or less, 85% of them had improved flexion postoperatively. A similar pattern of loss and gain occurred for functional movement of the knee. Reduced functional range was associated with significantly reduced physical quality of life compared with age-matched healthy subjects. CONCLUSION: Although TKA offers excellent pain relief and contributes to the overall well-being of the patient, these results suggest that it also leads to a reduced range of active and functional motion in the majority of patients. This is associated with a lower-than-normal physical quality of life. The design of implants and rehabilitation programmes should be reconsidered so that better range of motion and quality of life can be achieved for patients.

Male infertility: risk factors in Mongolian men.

AIM: To determine the most common risk factors of male infertility in Mongolian men attending an infertility clinic. METHODS: A prospective, case-control study was conducted in which 430 men were enrolled. All the men had sought their first infertility evaluation between 1998-2002 in the State Research Center on Maternal Child Health, Ulaanbaatar, Mongolia. They were divided into two groups depending on the results of their semen analysis: 191 with abnormal semen and 239 with normal semen profile. Univariate and multivariate analyses were performed to determine any association between risk factors and semen abnormality. RESULTS: Logistic regression analysis demonstrated that the testicular volume, a history of sexually transmitted infections (STI), epididymitis and testicular damage all have statistically significant associations with semen abnormality, when controlled for multiple risk factors. Adjusted odds ratios of 3.4 for mumps orchitis, 2.3 for other orchitis and 3.9 for testicular injury were found. Gonorrhoea, the most commonly reported STIs in this study, gave an adjusted odds ratio of 1.0 for having one or more sperm abnormality. An adjusted odds ratio for subjects with a history of other STIs was 2.7. However, as a predictor of azoospermia, STIs had very high odds ratio, being 5.6 in patients with gonorrhoea and 7.6 in patients with other STIs. CONCLUSION: A history of pathology involving testicular damage appeared to have the strongest impact on male infertility in Mongolia. STIs have less impact on semen quality except when complicated by orchitis, epididymitis and vasal obstruction.

Assessment of menstrual blood loss in Belgian users of the frameless copper-releasing IUD with copper surface area of 200 mm2 and users of a copper-levonorgestrel-releasing intrauterine system.

OBJECTIVE: This study was conducted to evaluate the effect of a miniaturized frameless copper IUD (GyneFix 200 small) and a copper-levonorgestrel (GynePlant) intrauterine system (IUS) on the amount of menstrual blood loss (MBL). METHODS: In 60 Belgian women using GyneFix 200 and 21 using GynePlant, MBL was assessed with the visual assessment technique. RESULTS: MBL scores in GyneFix 200 users did not change from baseline during the mean observation period of 31 months. In GynePlant users, mean MBL scores decreased by at least 50% in all but one user. CONCLUSION: The impact of copper IUDs on MBL can be minimized by reducing the surface area of the foreign body. Reduction of MBL, without causing amenorrhea, can be obtained by adding levonorgestrel.

Assessment of menstrual blood loss in women with ideopathic menorrhagia using the frameless levonorgestrel-releasing intrauterine system.

OBJECTIVE: This study was conducted to evaluate the effect of a "low-dose" levonorgestrel (LNG)-releasing intrauterine system (IUS) on the amount of menstrual blood loss (MBL) in women with ideopathic menorrhagia. METHODS: Menstrual blood loss was assessed with the visual assessment technique in 12 Belgian FibroPlant-LNG users with menorrhagia. In addition, ferritin levels were measured. RESULTS: The median MBL, evaluated by the visual scoring technique, decreased by more than 90%. The ferritin levels increased significantly during treatment with the levonorgestrel system. CONCLUSION: This study confirms previous MBL studies conducted with the FibroPlant-LNG IUS demonstrating the efficacy of the LNG-IUS to significantly reduce the amount of MBL in women with menorrhagia. The strong endometrial suppression is the principal mechanism explaining the effect on MBL. The therapeutic effect of this contraceptive method is highly desirable, particularly in women with heavy bleeding or anemia, as other treatment modalities are less effective, more costly, more invasive or inaccessible. The simple design characteristics and anchoring system account for minimizing the occurrence of complaints of pain and expulsion.

Assessment of menstrual blood loss in Brazilian users of the frameless copper-releasing IUD with copper surface area of 330 mm2 and the frameless levonorgestrel-releasing intrauterine system.

OBJECTIVE: This study was conducted to evaluate the effect of two types of IUDs on the amount of menstrual blood loss (MBL): the frameless copper-releasing intrauterine device (IUD) with copper surface area of 330 mm2 (GyneFix; Contrel Research, Ghent, Belgium) and the frameless levonorgestrel (LNG)-releasing intrauterine system (IUS) releasing 14 microg per day (FibroPlant-LNG; Contrel Research). Heavy and abnormal MBL is the main reason for discontinuation of intrauterine devices. METHODS: In 20 Brazilian women using GyneFix 330 and 32 using FibroPlant-LNG, respectively, MBL was measured by the quantitative alkaline hematin technique. In addition, ferritin levels were measured in GyneFix 330 and FibroPlant-LNG users. RESULTS: MBL with GyneFix 330, measured over a 24-month period, increased but was less when compared with TCu380A. Ferritin levels with GyneFix 330 were not affected in contrast with TCu380A. In FibroPlant-LNG users, mean MBL decreased by about 90% and ferritin levels increased significantly. CONCLUSIONS: The authors confirm earlier reports that, especially for women with low body iron stores and heavy menstrual bleeding, there is an order of preference for IUD use to minimize MBL. The choice should first be a progestin-releasing IUS, then a copper IUD, which has the least effect on menstrual bleeding, such as the frameless GyneFix IUD.

The use of colposcopy in assessing vaginal irritation in research.

Since the early 1990s, colposcopy of the vagina and cervix has been used in the development of vaginal products in order to detect epithelial changes that may increase the likelihood of HIV or acquisition of other sexually transmitted diseases. As part of a continued effort to examine and define the role of colposcopy in a research setting, the Contraceptive Research and Development Program (CONRAD) and the International Working Group on Microbicides (IWGM), in association with the United Nations Program for AIDS (UNAIDS) sponsored a conference entitled, 'The Use of Colposcopy in Assessing Vaginal Irritation in Research', held in Washington, DC in January 1999. This is a report of that conference. The World Health Organization's colposcopy procedure and nomenclature, published in 1995, were reviewed and changes were recommended. The revised procedure involves colposcopic examination of the external genitalia, naked eye examination of the cervix, fornices, and vaginal walls, followed by lavage and colposcopic examination of those areas, and sampling as appropriate for microscopic examination. Revised nomenclature replaces the terms used for findings with descriptions of what is actually seen. Digital video imaging and testing for inflammatory markers may be adjuncts to colposcopy and should be further studied. Other areas requiring additional research include the natural history of colposcopic changes, factors other than product use that may affect colposcopic findings, the clinical significance of findings, and the procedure which best assesses these findings.

Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life?

The knee joint kinematics of a group (n=20) of elderly normal subjects (mean age=67 years) were investigated using flexible electrogoniometry. The flexion-extension angle of the knee was recorded during a range of functional activities performed as part of a circuit in and around the hospital. The functions analysed including gait, walking on slopes, stair negotiation, the use of standard and low chairs and a bath. The data were used to produce the pattern of joint angulation against the percentage of the cycle for each individual conducting each activity. Further the maximum and minimum knee joint angles and the excursion of the joint during the cycle were identified. The results indicate gait and slopes require less than 90 degrees of knee flexion, stairs and chairs 90-120 degrees of flexion and a bath approximately 135 degrees of flexion. The data suggests that 110 degrees of flexion would seem a suitable goal for the rehabilitation of motion in the knee. It is concluded that flexible electrogoniometry is a suitable and practical method for evaluating knee motion during a range of functional activities.

What is balance?

Balance is a term frequently used by health professionals working in a wide variety of clinical specialities. There is no universally accepted definition of human balance, or related terms. This article identifies mechanical definitions of balance and introduces clinical definitions of balance and postural control. Postural control is defined as the act of maintaining, achieving or restoring a state of balance during any posture or activity. Postural control strategies may be either predictive or reactive, and may involve either a fixed-support or a change-in-support response. Clinical tests of balance assess different components of balance ability. Health professionals should select clinical assessments based on a sound knowledge and understanding of the classification of balance and postural control strategies.

A new system for the measurement of displacements of the human body with widespread applications in human movement studies.

This paper reports the development, construction and use of a new system for the measurement of linear kinematics in one, two or three dimensions. The system uses a series of rotary shaft encoders and inelastic tensioned strings to measure the linear displacement of key anatomical points in space. The system is simple, inexpensive, portable, accurate and flexible. It is therefore suitable for inclusion in a variety of motion analysis studies. Details of the construction, calibration and interfacing of the device to an IBM PC computer are given as is a full mathematical description of the appropriate measurement theory for one, two and three dimensions. Examples of the results obtained from the device during gait, running, rising to stand, sitting down and pointing with the upper limb are given. Finally it is proposed that, provided the constraints of the system are considered, this method has the potential to measure a variety of functional human movements simply and inexpensively and may therefore be a valuable addition to the methods available to the motion scientist.

Chlamydial urethral infection in male students in Chiang Mai: a screening test of urine deposits by enzyme immunoassay (EIA).

Adolescent males are considered to be an important genital chlamydial reservoir. However, there has been little information on urethral chlamydial infection in Thai adolescent males. About one fourth of males who are genital chlamydial reservoirs are asymptomatic. An appropriate means of defining the extent of chlamydial infection in adolescent males would be a non-invasive screening survey, instead of the conventional method of a deep swab cell culture, which is painful. The objectives of this study were to estimate the prevalence and to determine what factors should indicate the use of a screening test for urethral chlamydial infection in adolescent males residing in Chiang Mai. Chlamydial urethritis was detected by examining urine deposits for chlamydial antigen by enzyme immunoassay (EIA).

Development of a low-cost video vector for the display of ground reaction forces during gait.

Video vector systems offer a simple and valuable tool suitable for evaluating and analysing the biomechanics of human motion. These systems are capable of widespread applications in education, clinical evaluation and research. However, the literature indicated that current video vector systems are expensive and not widely available. The work presented in this study indicates an alternative method of constructing a video vector system which is inexpensive and relatively simple to build. The system uses a VGA to video adaptor to convert computer-generated graphics of the ground reaction force into a video formet. This picture can then be overlaid on to a video picture of the moving subject using a video mixer. By careful positioning of the camera and suitable perspective drawing of the computer image a true representation of the relationship between the force vector and the subject can be produced. The system has been found to be reliable, versatile and robust and has been used for a variety of motion analysis tasks. It is hoped that the work contained in this paper will encourage others to construct their own video vector systems using similar commercially available components and hence benefit from the considerable advantages that such a system can offer. This paper describes the design and construction of a simple, inexpensive video vector system which has been shown to be a useful biomechanical technique with widespread applications in the educational, clinical and research environments.