Timothy David Blackmore

The effect of socks on vertical and anteroposterior ground reaction forces in walking and running

BACKGROUND Previous research suggests that socks may have the potential for injury protection through the absorption and/or redistribution of impact forces. However, there is limited research regarding the shock attenuation qualities of athletic socks in sporting populations and previously observed pressure reductions have not been quantified using a force plate. OBJECTIVE Firstly to identify the effect of specialist athletic socks on vertical and anteroposterior ground reaction forces (GRFs) during walking and running. Secondly, to compare GRFs between specialist socks, non-specialist socks and barefoot walking and running conditions. METHODS Following ethical approval participants (n=5) completed five walking (1.52-1.68 m s(-1)) and running (3.8-4.2 m s(-1)) trials, unshod, over a force plate. This was completed before and after a 5000 m run (3.2 m s(-1)) in their own trainers in three conditions; barefoot, non-specialist socks and specialist running socks. RESULTS Significant differences were identified between barefoot and specialist sock conditions for pre-intervention time to impact peak (F=3.110((2)), P=.05, r=.11) and maximum propulsive force (F=8.126((2)), P=.001, r=.25) when walking. Post hoc analysis identified an increase of .0016 s in time to impact peak when walking barefoot compared to the specialist sock condition (T=-7.402((4)), P=.002, r=.71). During walking the specialist sock also demonstrated a significant decrease of .075 BWs in maximum propulsive force when compared to the barefoot condition (T=-7.624((4)), P=.002, r=.79). Both significant effects diminished following the 5000 m run. CONCLUSION Findings suggest that the specialist running sock has limited effects on GRFs and therefore may be responsible for a limited degree of shock attenuation experienced during walking.

The high frequency component of the vertical ground reaction force is a valid surrogate measure of the impact peak

Identification of the impact peak (IP) from the vertical ground reaction force (vGRF) is required to calculate indices of impact loading during running. The IP, however, is not always clearly discernible. Previous researchers have estimated the timing of the IP using surrogate methods, the most common of which is a set time point of 13% stance (TPS). Information contained within the high frequency (HiF) component of the vGRF may also have a utility as a surrogate measure, but the validity of either approach is currently unknown. The purpose of this study is to evaluate the criterion validity for a newly proposed HiF method and the previously used TPS method against a criterion measure for a group of rear-foot striking runners. Fifty participants ran at a standardized speed (3.3 m·s(-1)) on an instrumented treadmill. Five consecutive stance phases were analyzed for the participants dominant limb. Bland-Altman was used to assess agreement between the criterion method and each surrogate method. Good agreement of the HiF and TPS methods with the criterion method indicate that both methods are likely to be valid surrogate approaches to estimate vGRF impact loading indices. For all impact loading indices, smaller bias and limits of agreement (LOA) were observed with the HiF method when compared to the TPS method. Therefore, it is concluded that the HiF method should be used in preference to the TPS method when it is available.

Imposed Faster and Slower Walking Speeds Influence Gait Stability Differently in Parkinson Fallers

OBJECTIVE To evaluate the effect of imposed faster and slower walking speeds on postural stability in people with Parkinson disease (PD). DESIGN Cross-sectional cohort study. SETTING General community. PARTICIPANTS Patients with PD (n=84; 51 with a falls history; 33 without) and age-matched controls (n=82) were invited to participate via neurology clinics and preexisting databases. Of those contacted, 99 did not respond (PD=36; controls=63) and 27 were not interested (PD=18; controls=9). After screening, a further 10 patients were excluded; 5 had deep brain stimulation surgery and 5 could not accommodate to the treadmill. The remaining patients (N=30) completed all assessments and were subdivided into PD fallers (n=10), PD nonfallers (n=10), and age-matched controls (n=10) based on falls history. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Three-dimensional accelerometers assessed head and trunk accelerations and allowed calculation of harmonic ratios and root mean square (RMS) accelerations to assess segment control and movement amplitude. RESULTS Symptom severity, balance confidence, and medical history were established before participants walked on a treadmill at 70%, 100%, and 130% of their preferred speed. Head and trunk control was lower for PD fallers than PD nonfallers and older adults. Significant interactions indicated head and trunk control increased with speed for PD nonfallers and older adults, but did not improve at faster speeds for PD fallers. Vertical head and trunk accelerations increased with walking speed for PD nonfallers and older adults, while the PD fallers demonstrated greater anteroposterior RMS accelerations compared with both other groups. CONCLUSIONS The results suggest that improved gait dynamics do not necessarily represent improved walking stability, and this must be respected when rehabilitating gait in patients with PD.

The cushioning properties of athletic socks: An impact testing perspective

BACKGROUND One of the aims of the sock/shoe unit is to reduce the severity of impact forces on the lower extremity although the injury prevention potential of the sock through the attenuation of impact force has yet to be established. This study aims to determine the effect of athletic socks and a sock/shoe unit on peak impact force, time to peak impact force and loading rate using an impact testing methodology. METHODS An impact testing system with a gravity driven vertical impact striker (8.5kg) fitted with a load cell (10,000Hz) which was released from 0.05m to impact the specimen on the vertical axis (impact velocity=0.99m·s(-1)) was used throughout the study. FINDINGS All socks reduced peak impact force by between 6% and 20% when compared to a no sock control condition. Furthermore, large significant correlation coefficients (r=.62 to .72) were observed between thickness and peak impact force, time to peak impact force and loading rate in the sock only condition. INTERPRETATION Athletic socks demonstrate cushioning properties under impact testing conditions.

Evidence of compensatory joint kinetics during stair ascent and descent in Parkinson’s disease

BACKGROUND Stair ambulation is a challenging activity of daily life that requires larger joint moments than walking. Stabilisation of the body and prevention of lower limb collapse during this task depends upon adequately-sized hip, knee and ankle extensor moments. However, people with Parkinsons disease (PD) often present with strength deficits that may impair their capacity to control the lower limbs and ultimately increase their falls risk. OBJECTIVE To investigate hip, knee and ankle joint moments during stair ascent and descent and determine the contribution of these joints to the bodys support in people with PD. METHODS Twelve PD patients and twelve age-matched controls performed stair ascent and descent trials. Data from an instrumented staircase and a three-dimensional motion analysis system were used to derive sagittal hip, knee and ankle moments. Support moment impulses were calculated by summing all extensor moment impulses and the relative contribution of each joint was calculated. RESULTS Linear mixed model analyses indicated that PD patients walked slower and had a reduced cadence relative to controls. Although support moment impulses were typically not different between groups during stair ascent or descent, a reduced contribution by the ankle joint required an increased knee joint contribution for the PD patients. CONCLUSIONS Despite having poorer knee extensor strength, people with PD rely more heavily on these muscles during stair walking. This adaptation could possibly be driven by the somewhat restricted mobility of this joint, which may provide these individuals with an increased sense of stability during these tasks.

Dynamic balance control during stair negotiation for older adults and people with Parkinson disease

It is well understood that stability during ambulation is reliant upon appropriate control of the trunk segment, but research shows that the rhythmicity of this segment is significantly reduced for people with Parkinsons disease (PD). Given the increased risk associated with stair ambulation, this study investigated whether people with PD demonstrate poorer trunk control during stair ambulation compared with age-matched controls. Trunk accelerations were recorded for twelve PD patients and age-matched controls during stair ascent and descent. Accelerations were used to derive measures of harmonic ratios and root mean square (RMS) acceleration to provide insight into the rhythmicity and amplitude of segmental motion. Compared with what is typically seen during level-ground walking, gait rhythmicity during stair negotiation was markedly reduced for older adults and people with PD. Furthermore, both groups exhibited significantly poorer trunk movements during stair descent compared to stair ascent, suggesting that both populations may face a greater risk of falling during this task. As stair negotiation is a common activity of daily life, the increased risk associated with this task should be considered when working with populations that have an increased risk of falling.

Validity of visual rating of the lower extremity against 3D kinematics in people with an ACL injury

FP01-177 Clinical outcomes after fixation, arthroplasty and resection for treatment of comminuted fracture radial head (Mason type III or IV): a systematic review and network meta-analysis Arirachakaran, Alisara*; Boonard, M.; Kanchanatawan, W.; Kongtharvonskul, J. Orthopedics Department, Police General Hospital, Bangkok, Thailand; Srinakarin Hospital, Khonkaen, Thailand; Orthopedics Department, Lerdsin general hospital, Bangkok, Thailand; Mahidol University, Bangkok, Thailand Objectives: Radial head fractures make up approximately 3% of all fractures and they are the most common elbow fracture in adults. The treatment for comminuted radial head fracture remains controversial. Currently, the most frequently used treatment for comminuted radial head fracture is fixation, resection or arthroplasty. Therefore, we conducted a systematic review and network meta-analysis to compare the post-operative outcomes among surgical treatment and identify which method is the best for comminuted radial head fractures Mason type III–IV. Methods: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies were identified from Medline and Scopus from inception to August 18th, 2017 that reported Mayo elbow performance score (MYPS) and postoperative complications of either treatment. A network meta-analysis was applied to assess treatment outcomes. Probability of being besttreatment was estimated using surface under the cumulative ranking curves (SUCRA). Results: Twelve comparative studies and one RCT (N = 526 patients) met the inclusion criteria. Intervention included ORIF (N = 210 patient), RHA (N = 227 patients) and RHR (N = 152 patients). A network-meta-analysis showed that MYPS of RHA was significantly higher when compared to ORIF and RHR, with the pooled mean MYPS of 7.28 (1.69, 12.86) and -7.32 (-13.21, -1.43) respectively. In terms of complications, RHA and RHR had lower risk with RRs of 0.61 (0.29, 1.31) and 0.54 (0.24, 1.25) when compared to ORIF. The SUCRA probabilities of RHA and RHR were in the first rank with 99.2% in MYPS and 60.6% in complications, respectively. Conclusions: The best surgical treatment option class that have the highest post-operative function scores is radial head arthroplasty followed by ORIF in treatment comminuted radial head fracture Mason type III–IV. While the lowest risk of having complications after surgery is radial head resection followed by radial head arthroplasty. This study suggest radial head arthroplasty and resection that have the first rank for both safety and efficacy outcome should be recommend for treatment comminuted radial head fracture Mason type III–IV. Further research with an increased sample size and a prospective randomized controlled trial study design are required to determine as to which surgical treatment options be the best should be done in the future. FP01-545 Lower amputation rate after fasciotomy by straight midline incision technique for a 22,900-volt electrical injury to the upper extremities Lee, B. H.* Kang-Dong Sacred Heart Hospital, Hallym University Medical School, Seoul, Korea, Republic of (South Korea) Objectives: The purpose of this study is to compare the major amputation rate following two different fasciotomy techniques, conventional versus straight midline, in patients with high-voltage arc burn injury by electric currents of 22,900 V to the upper extremities. Methods: A retrospective analysis of 230 patients (270 burned upper limbs) who underwent fasciotomy after high-voltage electrical injuries between 1996 and 2007 was performed. The patients were divided into two groups according to the fasciotomy method used. From 1996 to 2002, 158 patients (184 limbs) underwent conventional fasciotomy by Green’s volar-ulnar incision (conventional fasciotomy group). From 2003 to 2007, 72 patients (86 limbs) underwent fasciotomy using a straight midline curved incision (midline fasciotomy group). The patients were also divided into two groups based on whether the fasciotomy procedure was performed early or late. Patients who underwent fasciotomies\ 8 h after injury were classified as early, while those who underwent it[ 8 h after injury were classified as late. Major amputation rates were compared between two fasciotomy methods and analyzed following fasciotomy timing. The incidence of major amputation was numbered and compared between the two groups. Statistical significance was determined using Pearson’s chi-square analysis or Fisher’s exact test. Results: The midline fasciotomy group had a significantly lower major amputation rate (33.7%) than the conventional fasciotomy group (59.2%) (p\ 0.001). A subsequently decreased major amputation rate of 27.8% was observed in the early fasciotomy subgroup of the midline fasciotomy group (p = 0.025). Most cases treated with microsurgery consisted of the trans-positional or rotational local flap in the conventional fasciotomy group as the second most common approach (20%; 15/75 limbs). It was almost impossible to perform direct skin repair using a shoelace suture or gradual wiring due to the extensive areas of the open wounds. After confirmation of the vascular condition using angiography, microsurgery was done to revascularize and restore better function in the involved limbs in good condition. In the midline fasciotomy group, wound coverage was possible using free vascularized flap surgery with omental free flaps or latissimus dorsi muscle flaps etc. Direct skin repair using a shoelace suture or gradual wiring could be also used to cover open wounds in 12.3% (7/57 limbs) of cases. Conclusions: Early fasciotomy remarkably reduced the major amputation rate after high-voltage arc injury; in the setting of minimized vascular exposure after fasciotomy, a midline straight incision could ensure that various types of reconstructive microsurgical procedures and primary skin closures can be used to save limbs.