STUDY PROTOCOL Open Access Rocker-sole Footwear Versus .
Menz et al. BMC Musculoskeletal Disorders 2014, TUDY PROTOCOLOpen AccessRocker-sole footwear versus prefabricated footorthoses for the treatment of pain associatedwith first metatarsophalangeal joint osteoarthritis:study protocol for a randomised trialHylton B Menz1,2*, Pazit Levinger1,3, Jade M Tan1,2, Maria Auhl1,2, Edward Roddy4 and Shannon E Munteanu1,2AbstractBackground: Osteoarthritis affecting the first metatarsophalangeal joint of the foot is a common condition whichresults in pain, stiffness and impaired ambulation. Footwear modifications and foot orthoses are widely used inclinical practice to treat this condition, but their effectiveness has not been rigorously evaluated. This articledescribes the design of a randomised trial comparing the effectiveness of rocker-sole footwear and individualisedprefabricated foot orthoses in reducing pain associated with first metatarsophalangeal joint osteoarthritis.Methods: Eighty people with first metatarsophalangeal joint osteoarthritis will be randomly allocated to receiveeither a pair of rocker-sole shoes (MBT Matwa, Masai Barefoot Technology, Switzerland) or a pair of individualised,prefabricated foot orthoses (Vasyli Customs, Vasyli Medical , Queensland, Australia). At baseline, the biomechanicaleffects of the interventions will be examined using a wireless wearable sensor motion analysis system (LEGSys ,BioSensics, Boston, MA, USA) and an in-shoe plantar pressure system (Pedar , Novel GmbH, Munich, Germany). Theprimary outcome measure will be the pain subscale of the Foot Health Status Questionnaire (FHSQ), measured atbaseline and 4, 8 and 12 weeks. Secondary outcome measures will include the function, footwear and general foothealth subscales of the FHSQ, severity of pain and stiffness at the first metatarsophalangeal joint (measured using100 mm visual analog scales), global change in symptoms (using a 15-point Likert scale), health status (using theShort-Form-12 Version 2.0 questionnaire), use of rescue medication and co-interventions to relieve pain, thefrequency and type of self-reported adverse events and physical activity levels (using the Incidental and PlannedActivity Questionnaire). Data will be analysed using the intention to treat principle.Discussion: This study is the first randomised trial to compare the effectiveness of rocker-sole footwear and individualisedprefabricated foot orthoses in reducing pain associated with osteoarthritis of the first metatarsophalangeal joint,and only the third randomised trial ever conducted for this condition. The study has been pragmatically designedto ensure that the findings can be implemented into clinical practice if the interventions are found to be effective, andthe baseline biomechanical analysis will provide useful insights into their mechanism of action.Trial registration: Australian New Zealand Clinical Trials Registry: ACTRN12613001245785* Correspondence: h.menz@latrobe.edu.au1Lower Extremity and Gait Studies Program, Faculty of Health Sciences, LaTrobe University, Bundoora 3086, Victoria, Australia2Department of Podiatry, Faculty of Health Sciences, La Trobe University,Bundoora 3086, Victoria, AustraliaFull list of author information is available at the end of the article 2014 Menz et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, andreproduction in any medium, provided the original work is properly credited. The Creative Commons Public DomainDedication waiver ) applies to the data made available in this article,unless otherwise stated.
Menz et al. BMC Musculoskeletal Disorders 2014, ackgroundOsteoarthritis (OA) is the leading cause of chronic painand disability in Australia. In 2013, it was estimated that1.9 million people in Australia had OA, and that this figureis expected to increase to 3 million people by 2032 [1]. Although the knee is the most commonly affected lower limbregion, foot involvement is also common. The most commonly affected region of the foot is the first metatarsophalangeal joint (MTPJ), with radiographic changes evidentin 12 to 35% of people aged over 35 years [2]. Thepopulation prevalence of symptomatic radiographicfirst MTPJ OA (i.e. both radiographic changes and associated symptoms) in people aged over 50 years hasrecently been estimated as 7.8%, with a higher prevalence observed in women, older people, and those fromlower socio-economic classes [3].People with first MTPJ OA typically present withsymptoms of pain and stiffness in their big toe joint thatincrease with activity. Because the first MTPJ plays animportant role in the transfer of the body during thepropulsive phase of gait, people with first MTPJ OA willoften adopt an apropulsive walking pattern with a shortened step length and longer stance phase duration [4],accompanied by excessive knee and hip flexion or hipcircumduction to assist the transfer of the swing limb[5] and decreased loading of the first MTPJ [6]. In ourrecently completed comparison of 43 cases and 43 controls, we found that symptomatic first MTPJ OA was associated with a statistically significant reduction in allsubscales of the Foot Health Status Questionnaire andthe physical function and subscale of the Medical Outcomes Study Short Form 36 questionnaire [7]. Inaddition, Abhishek et al. have reported that great toepain is associated with lower scores on the health satisfaction and psychological domains of the World HealthOrganization Quality of Life questionnaire [8], and a recent population-based study found that 72% of peoplewith symptomatic first MTPJ OA report disabling symptoms [3].Many patients with first MTPJ OA seek surgical treatment for their condition. A clinical audit of 785 cases offoot surgery in Australia between July 1995 and June 1996revealed surgery for this condition to be the fourth mostcommon procedure performed [9]. Similarly, a populationbased study of 6,956 inpatients in Sweden [10] indicatedthat these procedures accounted for 15% of all foot andankle procedures. Our recent analysis of the Medicare Benefits Schedule database indicated that between 1997 and2006, over 46,000 private sector surgical procedures fortreatment of first MTPJ disorders (hallux valgus and halluxrigidus) were subsidised under Medicare, at a direct cost ofapproximately 2 M per year [11]. These costs, however,are an underestimate of the total economic impact of thecondition. The 2013 Deloitte Access Economics analysisPage 2 of 13indicated that treatment expenses for OA accounted foronly 17% of the total cost of the disease, the remainingcosts being attributed to burden of disease and productivitylosses [1].The aetiology of first MTPJ OA is not fully understood. Increased age, previous trauma, family historyand a flat foot are commonly reported as contributingfactors in the literature, but few studies have beenundertaken to examine this in detail [5]. There is, however, evidence that certain structural characteristics ofthe foot are more common in those with first MTPJ OAcompared to controls. Our recent systematic review concluded that people with first MTPJ OA were more likelyto exhibit a dorsiflexed first metatarsal relative to thesecond metatarsal, a plantarflexed forefoot on the rearfoot, reduced first MTPJ joint range of motion, a longerproximal phalanx, distal phalanx, medial and lateral sesamoids, and a wider first metatarsal and proximal phalanx [12]. Although temporal relationships cannot beinferred from such studies, it has been hypothesised thatas a result of this altered foot structure, the first metatarsalis less able to plantarflex during propulsion to allow theproximal phalanx to dorsally rotate on the first metatarsalhead, resulting in dorsal joint compression of the firstMTPJ. Over time, this process results in cartilage damage,exposure of subchondral bone, juxta-articular sclerosis,and the formation of a dorsal osteophyte [5].Conservative treatment of first MTPJ OA involves measures to obtain pain relief (including anti-inflammatorymedications and intra-articular injections), physical therapy to maintain range of motion, and footwear and footorthoses to modify foot function. Surgical managementmay involve removal of the dorsal exostosis, insertion of ajoint implant, or, in advanced cases, fusion of the firstMTPJ [13]. However, despite the high prevalence of firstMTPJ OA and its impact on quality of life, very few ofthese treatments have been rigorously evaluated. Furthermore, in patients with more advanced disease, postsurgical complications such as transfer lesions, forefootpain, malunion and interphalangeal OA are common [14].Our recent systematic review of interventions for firstMTPJ OA [15] revealed only one low quality randomisedtrial evaluating the effectiveness of two different physicaltherapy programs in 20 participants [16]. Following thepublication of this review, we completed a randomisedcontrolled trial which found that intra-articular viscosupplementation (hylan G-F20) was no more effectivethan a placebo (sterile saline) for this condition [17].Clearly, there is a need for additional well-designed trials into non-surgical interventions for the treatment offirst MTPJ OA.The pain associated with first MTPJ OA generally occurs during the propulsive phase of gait when the proximal phalanx is compressed against the dorsal osteophyte
Menz et al. BMC Musculoskeletal Disorders 2014, n the first metatarsal head. Therefore, ameliorating theneed for the first MTPJ to dorsiflex has the potential to reduce joint compression and alleviate pain when walking.Clinically, this can be achieved using a footwear modification known as a rocker-sole, in which the sole of the shoeis curved (at the forefoot, rearfoot, or both) [18]. The aimof this modification is to allow the body’s centre of massto “roll over” the base of support, reducing the need forfoot and ankle dorsiflexion and subsequently decreasingthe loads placed on the forefoot. Biomechanical studieshave confirmed this proposed mechanism, indicating thatrocker-sole shoes reduce sagittal plane motion of the forefoot [19] and ankle [19-22], reduce forefoot plantar pressures [22,23] and reduce first MTPJ dorsiflexion [24] whenwalking. Such a change in biomechanics may be therapeutically beneficial in those with first MTPJ OA by reducingcompression at the first MTPJ. Although no controlledstudies have been performed, uncontrolled reports suggestthat rocker-sole shoes are effective in the management offirst MTPJ pain, and may in some cases prevent the needfor surgery [14,25,26].In both clinical practice and research, the main barrierto the use of therapeutic footwear is concern regardingaesthetics, and indeed, adherence to therapeutic footwear in people with diabetes or rheumatoid arthritis hasbeen reported to be as low as 22% [27-29]. However, therecent popularity of so-called “physiological” or “toning”footwear, pioneered by the Swiss company Masai Barefoot Technology (MBT), has made the rocker-sole shoemore fashionable. It is therefore likely that acceptabilityand adherence to this intervention will be much greaterthan that associated with the relatively unattractive medicalgrade footwear that has been used for this purpose previously. Indeed, a recent trial of MBT shoes for knee OA reported a drop-out rate of only 2% over 12 weeks [30].In addition to rocker-sole shoes, first MTPJ OA isoften managed with prefabricated or customised footorthoses. Foot orthoses are thought to decrease painassociated with this condition by allowing the firstmetatarsal to achieve sufficient plantarflexion in preparation for propulsion, thereby minimising joint compression [31]. Although widely used and recommendedin clinical practice guidelines [32], evidence to supportthe effectiveness of this approach is limited to case reports [26,33,34] and one recent case series study, whichdemonstrated a clinically significant reduction in painover 24 weeks in 32 participants [35].Given the prevalence and impact of first MTPJ OA, thelack of evidence for existing interventions, and the preliminary biomechanical and anecdotal evidence supportingthe use of rocker-sole shoes and prefabricated foot orthoses, there is a need to conduct a rigorous randomisedtrial to evaluate which of these non-invasive treatments ismost effective.Page 3 of 13MethodsThe trial has been registered on the Australian NewZealand Clinical Trials Registry (ACTRN12613001245785).Ethical approvalThe La Trobe University Human Ethics Committee hasprovided ethical approval (number 13–003). All participants will provide written informed consent prior to enrolment. Ethical standards will adhere to the NationalHealth and Medical Research Council (NHMRC) NationalStatement [36] and the World Medical Association'sDeclaration of Helsinki [37]. Publications associatedwith the trial will be reported according to the ConsolidatedStandards of Reporting Trials (CONSORT) 2010 Statement [38,39].DesignThe study design is a parallel-group randomised trialwith 12 week follow-up (see Figure 1), comparing two interventions: commercially available rocker-sole footwear(MBT Matwa, Masai Barefoot Technology, Switzerland)versus prefabricated foot orthoses (Vasyli Customs, VasyliMedical , Queensland, Australia). The study has beendesigned using the principles described by Osteoarthritis Research Society International Clinical Trials TaskForce guidelines [40]. Permuted block randomisation withrandom block sizes, stratified by sex, will be undertakenusing an interactive voice response telephone service provided by the NHMRC Clinical Trials Centre at the University of Sydney, New South Wales, Australia to ensureallocation concealment. Participants will be informed thatthey will receive either the rocker-sole footwear or thefoot orthoses (i.e. they will not be blinded to their groupallocation). Due to the nature of the intervention, researchstaff administering the treatments cannot be blinded togroup allocation. However, follow-up assessment of outcome measures will be via self-completion questionnairesreturned by mail, and those entering outcome measuredata and conducting statistical analyses will be blinded.Participant recruitment, screening and eligibility criteriaTo be included in the study, participants must:(i) be aged at least 18 years;(ii) report having pain in the first MTPJ on most daysfor at least 12 weeks;(iii) report having pain rated at least 20 mm on a100 mm visual analogue scale (VAS);(iv) have less than 64 degrees of dorsiflexion range ofmotion of the first MTPJ [41];(v) have pain upon palpation of the dorsal aspect ofthe first MTPJ;(vi) be able to walk household distances ( 50 meters)without the aid of a walker, crutches or cane;
Menz et al. BMC Musculoskeletal Disorders 2014, age 4 of 13Figure 1 Trial profile.(vii) be willing to attend the Health Sciences Clinic atLa Trobe University (Melbourne, Victoria) on twooccasions and have their foot x-rayed;(viii) be willing to not receive additional interventions(such as physical therapy, foot orthoses, shoemodifications, intra-articular injections, or surgery) for the first MTPJ pain during the course ofthe study;(ix) be willing to discontinue taking all medications torelieve pain at their first MTPJ (analgesics and nonsteroidal anti-inflammatory medications [NSAIDs],except paracetamol up to 4 g/day) for at least 14 daysprior to the baseline assessment and during thestudy period. Participants who do take paracetamolfor first MTPJ pain need to discontinue its use atleast 24 hours prior to the baseline assessment andfollow-up assessments at 4, 8 and 12 weeks.Exclusion criteria for participants in this study will be:(i) pregnancy;(ii) previous surgery on the first MTPJ;(iii) significant deformity of the first MTPJ includinghallux valgus (grade of 3 or 4 scored using theManchester Scale) [42,43];(iv) presence of one or more conditions within the footor ankle, in the opinion of the investigators, couldconfound pain and functional assessments of thefirst MTPJ, such as metatarsalgia, plantar fasciitis,pre-dislocation syndrome, Achilles tendinopathy,degenerative joint disease (other than the firstMTPJ);(v) presence of any systemic inflammatory condition,such as inflammatory arthritis, rheumatoidarthritis, ankylosing spondylitis, psoriatic arthritis,
Menz et al. BMC Musculoskeletal Disorders 2014, eactive arthritis, septic arthritis, acute pseudogout,gout or any other connective tissue disease;(vi) any medical condition that, in the opinion of theinvestigators, makes the participant unsuitable forinclusion (e.g., severe progressive chronic disease,malignancy, clinically important pain in a part ofthe musculoskeletal system other than the firstMTPJ, or fibromyalgia);(vii) cognitive impairment (defined as a score of 7 on theShort Portable Mental Status Questionnaire) [44];(viii) intra-articular injections into the first MTPJ in theprevious 6 months;(ix) currently wearing contoured foot orthoses(although flat insoles will be permitted);(x) currently wearing specialised footwear (footwearthat has been custom-made or ‘prescribed’ by ahealth-care practitioner);(xi) currently wearing shoes that would not be able toaccommodate a foot orthosis, or;(xii) older people with a history of recurrent falls(defined as 2 or more falls in the previous12 months), as there is some evidence that rockersole shoes may have short-term detrimental effects on balance [45].Participants will be recruited by advertisements placedin local newspapers, magazines, and social media, byposters placed in healthcare facilities, senior citizens’centres, retirement villages and mail-out advertisementsto health care practitioners in Melbourne. Although therecruitment strategy will focus on older people (due totheir increased prevalence of OA), our inclusion criteriaare not restricted to those aged over 65 years, as in ourrecently completed RCT of visco-supplementation forfirst MTPJ OA [17], the age range of participants withfirst MTPJ pain and radiographically confirmed firstMTPJ OA was 22 to 81 years, with a mean age of54 years, indicating that the condition is also prevalentin younger and middle-aged people.Rocker-sole footwear groupThe rocker-sole footwear group will be provided with apair of appropriately-sized rocker-sole shoes (MBT Matwa, Masai Barefoot Technology, Switzerland). Thisshoe is characterised by a rounded sole in the anteroposterior direction and a soft cushioned heel. Across thefull size range, the radius of curvature of the MBT is onaverage 33 cm overall, 18 cm at the forefoot, 43 cm atthe midfoot, and 11 cm at the heel [46]. See Figure 2.Page 5 of 13Figure 2 MBT Matwa footwear.modified using a similar approach to that described byWelsh et al. [35]. All orthoses will be full-length, butmodified by adding a first ray cut-out and trimming thedistal edge to the level of the 2nd to 5th toe sulci. In participants with pronated feet, full length 4-degree medial(varus) wedges (Formthotics, Foot Science International,Christchurch, New Zealand) will be applied to the underside of the foot orthoses (see section on the Foot PostureIndex below). Those who do not have pronated feet willhave open cell polyurethane foam applied to the plantaraspect of the rearfoot. See Figure 3.Baseline assessmentsDemographic factors, major medical conditions, healthrelated quality of life and anthropometricsDemographic factors (such as age, sex, education and income), major medical conditions and number of medications currently prescribed, will be obtained via a structuredquestionnaire. Height and weight will be measured using astadiometer and digital scales, respectively, and body massindex will be calculated as weight (kg)/height (m)2. Inaddition, two questionnaires will be included at baselineas potential predictors of treatment outcome: the PainCatastrophizing Scale, a questionnaire containing 13 itemsreflecting elevated negative cognitive responses to pain[47], and relevant questions from the Monitor OrthopaedicShoes questionnaire [48], which assesses participants’ expectations of footwear-related interventions. Footwear willalso be assessed using selected items from the FootwearAssessment Tool [49].Clinical assessment of first MTPJ OA featuresThe following clinical observations will be used to characterise the clinical features of first MTPJ OA in thesample. The reliability of these observations has been reported in detail previously (kappa values from 0.41 to1.00 [41]).Prefabricated foot orthoses groupThe prefabricated foot orthoses group will receive a pairof foot orthoses (Vasyli Customs – medium density,Vasyli Medical, Queensland, Australia) that will be(i) dorsal exostosis: the presence of a definite dorsalbony exostosis will be determined via visualobservation of the first MTPJ;
Menz et al. BMC Musculoskeletal Disorders 2014, age 6 of 13Figure 3 Prefabricated foot orthoses to be used in the trial. Top: plantar surface of left foot orthosis. Bottom: dorsal surface of right foot orthosis.(ii) effusion: a palpable joint effusion around thedorsal, dorso-medial and dorso-lateral regionswill be determined using manual palpation. Aneffusion will be classified as present if the area iscompressible and displacement of fluid noted;(iii) pain during motion: the examiner will grasp theproximal phalanx of the hallux and dorsiflex thedigit until movement is no longer possible. Thisprocess will be repeated 5 times with a positive testresult concluded if end range of motion producespain in at least 2 of the test trials;(iv) hard end-feel: the examiner will grasp the proximalphalanx and dorsiflex the hallux until movement isno longer possible. A positive test result will bedocumented if a hard osseous end-feel is determinedas opposed to a gradual end-feel of joint motion [50];(v) crepitus during dorsiflexion: the examiner will applya compressive force while moving the joint throughits full range of dorsiflexion motion. This processwill be repeated 5 times with a positive test resultdocumented if a grating or cracking sensationoccurs during at least 2 of the test trials [51];(vi) first MTPJ dorsiflexion range of motion: the passive,non-weightbearing, dorsiflexion range of motion ofthe first MTPJ will be measured in accordance to theprocedure described by Hopson et al. [52]. The firstmetatarsal and proximal phalanx of the hallux willinitially be bisected in the sagittal plane. Adorsiflexion force will be applied to the hallux untilend range of motion is reached, allowing the first rayto maximally plantarflex. The angle between thetwo lines will then be measured via a hand held goniometer. This measurement technique has beenshown to be highly reliable in people with first MTPJpain (intra-class correlation coefficient of 0.95 [41]).The assessment will be performed twice and theaverage score will be documented.Foot Posture Index (FPI)To help determine the amount of rearfoot control to beadded to the orthoses in the prefabricated foot orthosesgroup, the FPI will be documented. The FPI is a validand reliable clinical assessment tool [53] which consistsof six specific criteria: talar head palpation, supralateraland infralateral malleolar curvature, calcaneal frontalplane position, prominence in the region of the talonavicular joint, medial arch height and abduction and adduction of the forefoot on the rearfoot. Each FPI criterion isscored on a 5-point scale (range, 2 to 2). The sixscores obtained are then summated to give an overallscore of foot posture. The summated score has the potential to range from 12 (highly supinated) to 12 (highlypronated). The normal FPI (defined as 1 standard deviation from the mean) has been reported to be 1 to 7[54]. Therefore, participants who score greater than 7 willbe deemed to have pronated foot posture, and will havefull length medial wedges applied to the plantar aspect ofthe foot orthoses. The magnitude of the wedge angulation
Menz et al. BMC Musculoskeletal Disorders 2014, ill be increased until there is a reduction in the FPI scoreof at least 2 points [35]. Those with an FPI score less than7 will have open cell polyurethane foam applied to theplantar aspect of the rearfoot.Three-dimensional foot scanningThe FotoScan 3D foot scanner (Precision 3D Ltd, Westonsuper-mare, UK) will be used to obtain fully weight bearingscans of both feet. Participants will be instructed to standrelaxed with their feet approximately shoulder width apartand their hands clasped lightly in front of them or gentlyresting on the support rail if required. The FotoScan 3D device uses a fixed system of cameras and projectors to obtaindigital images of the foot, which are then automaticallyconverted to 3D models. According to the manufacturer,the scans obtained with this system are accurate to withinless than half a millimetre.Radiographic assessment of OAThe presence of radiographic OA will not be an inclusion criterion, as in clinical practice, footwear interventions are often provided on the basis of clinical findingswithout confirmation of radiographic changes. However,to document the radiographic severity of OA, weightbearing dorso-plantar and lateral radiographic projections will be obtained from the most symptomatic foot(or in the case of equivalent bilateral symptoms, theright foot), with the participant standing in a relaxed bipedal stance position. All x-rays will be taken by thesame medical imaging department using a ShimadzuUD150LRII 50 kw/30 kHz Generator and 0.6/1.2P18DE-80S high speed x-ray tube from a ceiling suspended tube mount. AGFA MD40 CR digital phosphorplates in a 24 cm 30 cm cassette will be used. The tubewill be angled 90 degrees and centred at the base of thethird metatarsal, with the film focus distance set at100 cm. All radiographs will be examined by HBM, SEMand JMT, to determine the presence of OA, using aradiographic atlas of foot OA developed by our group[55,56]. The reliability of assessments using this atlashave been reported in detail previously (kappa valuesgreater than 0.76 [55]).Treatment preference and credibility/expectationIn open randomised trials of musculoskeletal disorders, ithas been demonstrated that participants who are allocatedto their preferred treatment achieve better outcomes thanthose who do not receive their preferred treatment, despite the randomisation process resulting in equivalentbaseline outcome measure scores [57]. To address thisissue, participants will be asked if they have a preferencefor either treatment (documented as rocker-sole shoes,prefabricated foot orthoses or no preference), althoughtheir response will not influence their randomised groupPage 7 of 13allocation [58]. This approach conserves all the advantagesof a fully randomised design but enables the interactionbetween preference and outcomes to be quantified [59]. Arelated issue is treatment credibility (participants’ beliefsabout the logic underpinning the intervention) and treatment expectancy (participants’ perceptions of how muchthey may benefit) [60]. To quantify this, the Credibility/Expectancy Questionnaire (CEQ) [61] will be administered after randomisation. The CEQ consists of six items:three related to credibility and three related to expectancy.For each item, participants will be asked to rate the credibility of the treatment and their expectations on a 9-pointLikert scale. High scores on the scale indicate that the participant considers the treatment to be credible and expectsthe treatment to be effective. The CEQ has been shown tohave good internal consistency and test-retest reliability[61], and has recently been used to assess the credibility ofsham dry needling [62] and sham foot orthoses [63] usedin clinical trials.Biomechanical evaluationBecause the proposed mechanism of action of therocker-sole shoes is a change in biomechanical functionof the lower limb, two approaches will be used to evaluate their effects at the baseline appointment. First,spatio-temporal parameters and three-dimensional motion of the thigh and lower leg during gait will be recorded using a wireless, wearable sensor motion analysissystem (LEGSys , Biosensics, Boston, MA, USA). Thissystem consists of accelerometers and gyroscopes attachedwith Velcro straps to each lower leg and thigh. Themethod for calculation of the spatio-temporal parametersof gait is described in detail elsewhere [64]. To summarise,the gait phases are determined from the precise events ofheel-strike (initial foot contact) until toe-off (terminal footcontact). These events are extracted from gyroscopes attached to each shank through a local minimal peak detection scheme. Based on each participant’s height and usinga biomechanical model, spatial parameters (i.e. stridelength and stride velocity) and kinematics (knee and hip)are estimated by integration of the angular rate of rotationof the thigh and shank relative to the waist sensor. Gaitanalysis with this system has been validated in healthycontrols [64], older people [65], and patients with hiposteoarthritis [66]. After a familiarisation period, participants will complete 4 walking trials for each footwear condition over an 8 metre distance. To exclude the effect ofacceleration and deceleration steps, only the middle foursteps from each trial will be included for analysis. An average recording will be determined from the 16 steps (4steps from 4 trials) for each condition. Second, plantarpressures (specifically, peak pressure under the hallux, firs
footwear, pioneered by the Swiss company Masai Bare-foot Technology (MBT), has made the rocker-sole shoe more fashionable. It is therefore likely that acceptability and adherence to this intervention will be much greater than that associated with the relatively unattractive medical grade footwear that has been used for this purpose previ-ously.
viewed from the front of the engine. The cylinders are numbered from the front end of the engine. The engine firing order is 1-5-3-6-2-4. Each cylinder has three rocker levers. The rocker lever nearest to the center of the housing is the intake lever. Exhaust rocker lever (1) Injector rocker lever (2) Intake rocker lever (3)
arm to open and close the valve. To determine the load that would be seen by the rocker arm we found the spring rate that would be forcing against the rocker arm. With the spring constant k, a cam profile that gave us the maximum lift of the valve and the seat pressure of the valve, we were able to deter
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Specialty Wiring and Instructional Guide for: This guide provides instructions, rocker switch wiring diagrams and information for multiple carling V-series rocker switches with 10 terminals, and two independent lights. Use this guide when you want an ON-OFF-ON rocker switch to provide power to two loads when in the UP position, and only one of .
continuously, and this is a DOUBLE-ROCKER mechanism. (a) Link 1 xed: CRANK-ROCKER. (b) Link 2 xed: DRAG-LINK. (c) Link 3 xed: CRANK-ROCKER. (d) Link 4 xed: DOUBLE-ROCKER. Figure 2: The four inversions of Problem 2. ME 314 Chapter 1 HW August 29, 2011 Problem 1.4. I constructed the ADAMS mo
suspension is similar to Rocky 1. The auxiliary rocker can rotate around the hinge on the main rocker and The left and right main rocker arm can realize the differential movement around the differential mechanism so that the six wheels always touch the ground at the same time. In addition, t
EGP Exterior Gateway Protocol OSPF Open Shortest Path First Protocol IE-IRGP Enhanced Interior Gateway Routing Protocol VRRP Virtual Router Redundancy Protocol PIM-DM Protocol Independent Multicast-Dense Mode PIM-SM Protocol Independent Multicast-Sparse Mode IGRP Interior Gateway Routing Protocol RIPng for IPv6 IPv6 Routing Information Protocol PGM
A rocker arm is a valve train component in internal combustion engines. As a rocker arm is acted on by a camshaft lobe, it pushes open . reduced at the point of contact with the valve stem by a roller cam follower. A similar arrangement transfers the motion via another
