Stephen W. Hill

Altered kinetic strategy for the control of swing limb elevation over obstacles in unilateral below-knee amputee gait

Our goal was to document the kinetic strategies for obstacle avoidance in below-knee amputees. Kinematic data were collected as unilateral below-knee traumatic amputees stepped over obstacles of various heights in the walking path. Inverse dynamics were employed to calculate power profiles and work during the limb-elevation and limb-lowering phases. Limb elevation was achieved by employing a different strategy of intra-limb interaction for elevation of the prosthetic limb than for the sound limb, which was similar to that seen in healthy adult non-amputees. As obstacle height increased, prosthetic side knee flexion was increased by modulating the work done at the hip, and not the knee, as seen on the sound side. Although the strength of the muscles about the residual knee was preserved, the range of motion of that knee had previously been found to be somewhat limited. Perhaps more importantly, potential instability of the interface between the stump and the prosthetic socket, and associated discomfort at the stump could explain the altered limb-elevation strategy. Interestingly, the limb-lowering strategy seen in the sound limb and in non-amputees already features modulation of rotational and translational work at the hip, so an alternate strategy was not required. Thus, following a major insult to the sensory and neuromuscular system, the CNS is able to update the internal model of the locomotor apparatus as the individual uses the new limb in a variety of movements, and modify control strategies as appropriate.

Kinematic patterns of participants with a below-knee prosthesis stepping over obstacles of various heights during locomotion

Abstract The focus of this paper was to examine the lead limb preference and the kinematic patterns of the lead limb of participants with a unilateral below-knee prosthesis when stepping over obstacles of different heights. Firstly, ten unilateral below-knee amputees stepped over obstacles of three different heights placed in their walking path to determine if they had a lead limb preference. Five of the ten participants demonstrated a sound limb lead preference, two participants showed a prosthetic limb lead preference and three showed no preference at all. Seven of these participants subsequently stepped over obstacles of six different heights leading with their sound or prosthetic limb as observed in the first experiment, while whole body kinematic data were collected. Relative joint angles of the stance and swing limb were calculated when the swing limb was over the obstacle. Swing hip elevation and hip and knee flexion increased as functions of obstacle height. Stance limb hip flexion, knee flexion and (on the sound side) ankle plantarflexion increased slightly with increasing obstacle height, but stance limb hip elevation did not. Therefore, it appears that these stance limb modulations served to position the pelvis further back from the obstacle as obstacle height increased. The posterior shell of the prosthetic socket limited residual limb swing knee flexion, and the increased ankle dorsiflexion seen on the lead sound side was not present on the lead prosthetic side. These limitations were associated with increased swing prosthetic foot angle and increased stance ankle plantarflexion. These results provide insights into the adaptability of the locomotor system, and have implications for lower extremity prosthetic design and amputee rehabilitation.

A clinical study of the biomechanics of step descent using different treatment modalities for patellofemoral pain

INTRODUCTION In the previous study we have demonstrated that in healthy subjects significant changes in coronal and transverse plane mechanics can be produced by the application of a neutral patella taping technique and a patellar brace. Recently it has also been identified that patients with patellofemoral pain syndrome (PFPS) display alterations in gait in the coronal and transverse planes. OBJECTIVE This study investigated the effect of patellar bracing and taping on the three-dimensional mechanics of the knee of patellofemoral pain patients during a step descent task. METHOD Thirteen patients diagnosed with patellofemoral pain syndrome performed a slow step descent. This was conducted under three randomized conditions: (a) no intervention, (b) neutral patella taping, (c) patellofemoral bracing. A 20cm step was constructed to accommodate an AMTI force platform. Kinematic data were collected using a ten camera infra-red Oqus motion analysis system. Reflective markers were placed on the foot, shank and thigh using the Calibrated Anatomical System Technique (CAST). RESULTS The coronal plane knee range of motion was significantly reduced with taping (P=0.031) and bracing (P=0.005). The transverse plane showed a significant reduction in the knee range of motion with the brace compared to taping (P=0.032) and no treatment (P=0.046). CONCLUSION Patients suffering from patellofemoral pain syndrome demonstrated improved coronal plane and torsional control of the knee during slow step descent following the application of bracing and taping. This study further reinforces the view that coronal and transverse plane mechanics should not be overlooked when studying patellofemoral pain.

The biomechanics of step descent comparing an elasticated tubular bandage with neutral patellar taping in patellofemoral pain patients

Purpose: The purpose of this studywas to investigate disease specific and respiratory function measures that may influence physical activity levels and exercise capacity in people with Huntington’s disease. Relevance: Huntington’s disease (HD) is a neurodegenerative condition resulting in motor, cognitive and behavioural dysfunction. As with Parkinson’s disease and multiple sclerosis,physiotherapy management focuses on maintaining functional ability as long as possible. Ability to function and participate in activities of daily life will depend upon the pathophysiology of the condition as well as respiratory function. There is limited evidence concerning factors that influence physical activity levels and exercise capacity in people with HD. The results of this study will enable physiotherapists to use an evidence-based approach to the assessment and management of patients’ problems. Participants: Eighteen (7 female; mean (SD) age 51.2 (13.6) patients with HD were selected from a HD research and management clinic. Inclusion criteria were: symptomatic of HD;able to walk with or without assistance. Methods: A cross-sectional observational method was used. Descriptive data collected were: age; total functional capacity (TFC) from standardised questionnaire. Dependant variables measured were: physical activity level (MET-minutes/week)from International Physical Activity Questionnaire (IPAQ)short form; exercise capacity (meters) measured by six minute walk test (6 MWT). Independent variables measured were: Forced Vital Capacity in litres (FVC), a global measure of respiratory function measured following American Thoracic Society Guidelines; Unified Huntington’s Disease Rating Scale-Total Motor Score (UHDRS-TMS), a disease specific measure of motor function. Analysis: Data were analysed using Pearson’s correlations and where appropriate stepwise linear regression. Results: Descriptive data of all variables are as follows: mean (SD) TFC was 4.35 (2.4) (available range 0–14, higher scores indicate greater functional level); IPAQ median 328MET-minutes/week (low activity level); 6MWT mean (SD) was 191.95 meters (105.78); UHDRS-TMS mean (SD) 61.73 (12.02) (available range 0–120, higher scores indicating decreased motor function); FVC mean (SD) 2.19 L (1.00). FVC correlated with 6MWTand IPAQ (r = 0.44, 0.61 respectively); UHDRS correlated negatively with 6MWT and IPAQ (r =−0.63, r =−0.42 respectively). Linear regression results: UHDRS-TMS predicted 6MWT (R2 = 0.40, 6MWT= 536.1–5.6 (UHDRS-TMS), FVC was excluded; FVC predicted IPAQ (R2 = 0.37, IPAQ=−135.2 + 225.6 (FVC), UHDRS-TMS was excluded. Conclusions: In patients with HD, 6MWT is more influenced by UHDRS-TMS than respiratory function, however respiratory function predicted self-reported physical activity level. Slow gait due to motor function impairment may curtail 6MWTcompletion, while respiratory function may limit daily activities. Based on this study, it appears that the ability to function and participate in activities is multifactorial which requires consideration for physiotherapy management of people with neurodegenerative conditions. The results of this study are limited to patients who reported low activity levels and lowTFC scores; but are part of a larger study which will increase the power of the study. Implications: Ability to function and participate in activities is dependent on underlying disease process and respiratory function, and both elements should be considered when assessing and developing management strategies for people with neurodegenerative conditions.Purpose: To investigate the effects of three cueing devices (visual, auditory, and somatosensory) on movement and muscular control during gait initiation in people with Parkinson’s disease who experience freezing and to ascertain the acceptability of these cueing devices to novice users. Relevance: Over six million people worldwide are affected by Parkinson’s disease. It is estimated that thirty percent may experience freezing (an inability to produce effective steps) and have difficulty initiating gait, and maintaining gait whilst negotiating obstacles. This limits their capacity for physical activity and ability to participate in usual activities, and can result in social isolation. Various sensory cues have been shown to improve on-going gait in people with Parkinson’s Disease, but there is limited evidence on their effectiveness for people with gait initiation difficulties. Jiang and Norman (2006) found that transverse line visual cues improved gait initiation, while auditory cues had no effect. Dibble et al. (2004), using auditory and cutaneous cues during maximal speed gait initiation found an adverse effect on movement outcomes. Portable cueing devices are commercially available, however their influence in gait initiation and acceptability to users is currently unknown. InformaWPT2011, Research Report Abstracts eS773 tion on their effectiveness would enable physical therapists to provide better informed advice to potential purchasers. Participants: Twenty participants with idiopathic Parkinson’s disease and a history of freezing of gait (evaluated using item 14 of the Unified Parkinson’s Disease Rating Scale) were recruited; 14 males and 6 females, mean age 68 years and 11.5 years since diagnosis. Methods: An experimental trial of five randomised conditions: laser cane, sound metronome, vibrating metronome, walking stick and uncued. After using each cue participants’ opinions were obtained via a questionnaire. Motion data were collected using a 10 camera motion analysis system, force platforms and surface Electromyography. Analysis: Questionnaire responses from twelve participants who experienced freezing during testing were analysed using a Wilcoxon signed ranks test. Motion data from these participants were analysed using one-way ANOVA tests with post-hoc pair-wise comparisons to test for differences between conditions. Results: Significant differences were seen in step length, Centre of Mass and Centre of Pressure movement in the anterior/ posterior and medial/lateral directions between freezing and non-freezing episodes. The post hoc pair-wise comparisons showed significant improvements in the Centre of Mass and Centre of Pressure movement when using the laser cane and the walking stick and greater step length when using the laser cane. Participants rated the perceived effectiveness of the devices, theWilcoxon test showed a significant improvement in satisfaction when using the laser cane for both starting and maintaining walking (p < 0.05). Conclusions: The laser cane was overall the most effective cueing device for people with Parkinson’s disease and gait initiation difficulties in both user’s perception and efficacy tested in the gait laboratory. However the longer term effectiveness and acceptability of cueing devices at home and outdoors requires further investigation. Implications: This study would support the use of the laser cane as a relatively cheap intervention for people with Parkinson’s disease who experience spontaneous freezing.Purpose: This study investigated the effect of an elasticated tubular bandage and neutral patella taping on the threedimensional mechanics of the knee during slow step descent in a group of subjects suffering from Patellofemoral Pain Syndrome (PFPS). Relevance: A number of studies have demonstrated that subjects with patellofemoral pain syndrome have poor eccentric control at the knee. Most previous studies have focused on the use of taping, braces or neoprene knee sleeves; this is the first study to investigate the effect of the low cost alternative of an elasticated tubular bandage on eccentric control during step descent in a PFPS population. Participants: Ten subjects (4 men:6 women) with a diagnosis of patellofemoral pain syndrome referred to a Primary Care Musculoskeletal physiotherapy service (NHS Central Lancashire) for treatment were recruited (Mean: age = 28; Modified Functional Index Questionnaire score = 26; Visual Analogue Scale for Usual Pain in the past week = 29 mm). Inclusion criteria were; presence of traumatic or idiopathic peripatellar pain and pain provoked by deep squatting, kneeling, ascending or descending stairs; alone or in combination. Exclusion criteria; any history of knee surgery. Methods: Slow step descent was used to assess the control of the knee under three randomised conditions: (a) no intervention, (b) elasticated tubular bandage, and (c) neutral patella taping. Kinematic and kinetic data were collected using a ten camera Oqus (Qualisys) motion analysis system and two AMTI force platforms. The segments of the lower limbs were modelled in six-degrees of freedom and joint kinematics and moments were calculated at the knee. Post testing, subjects were asked to rank the test conditions in order of preference. Analysis: A repeated measures (RM) ANOVA was performed together with post hoc pairwise comparison for the coronal and transverse plane knee angles and moments about the knee, comparing the three randomised conditions. A further RMANOVA was conducted to investigate differences in the sagittal plane knee angular velocity in order to confirm that observed differences were not artefacts of descent velocity. Significance was set to P≤0.05. Results: The coronal plane knee range of motion was significantly reduced with taping (P = 0.032) and the tubular bandage (P = 0.006). No significant differences were seen in any other plane or for knee angular velocity or moments. Subjects ranking preference of the test conditionswas evenly split between the two interventions: neutral patella taping (N=5) and elasticated tubular bandage (N= 4); only one subject stated they would prefer to have nothing on their knee. Conclusions: The use of an elasticated tubular bandage and a neutral patella taping technique actually produced a measurable change in the control mechanism of the knee and resulted in subjects with PFPS demonstrating greater knee control and less pain during a step descent when compared to no intervention. The tubular bandage had the greatest mechanical effect, reducing movement in the coronal plane by 30% when compared to no intervention. Implications: An elasticated tubular bandage and neutral patellar taping may represent low cost, convenient interventions in the management of mild Patellofemoral Pain Syndrome.Purpose: Patients with juvenile idiopathic arthritis (JIA) are less physically active than healthy peers. Therefore we developed an internet-based intervention to improve physical activity (PA). The aim of the study was to examine the effectiveness of the program in improving PA. Relevance: Evidence is accumulating that PA is effective in the primary and secondary prevention of several chronic conditions. PA is also associated with a reduction in all-cause mortality. There is evidence that in youth aged 6-16 years, PA controls body weight, reduces blood pressure in hypertensive youth, improves aerobic capacity, muscular strength, endurance and skeletal health, reduces anxiety and depression and improves self concept. PA also has a positive effect on academic performance, concentration, memory and classroom behavior. For children with JIA and other chronic diseases it is recognized that they could take advantage of the same health benefits. Participants: All patients with JIA, registered in the University Medical Center Groningen, the Netherlands and aged 8-12 years, were selected for this study. Inclusion criteria were a diagnosis of JIA, a good comprehension of the Dutch language and the availability of a home-based computer with an internet connection. Methods: PA was determined by activity-related energy expenditure (AEE), PA level, time spent on moderate to vigorous PA and the number of days with 1 hour or more of moderate to vigorous PAand was assessed with a 7-day activity diary. Aerobic exercise capacity was assessed by means of a Bruce treadmill test and recorded as maximum endurance time. Disease activity was assessed by using the JIA core set. Adherence was electronically monitored. Analysis: Descriptive statistics were used for patients characteristics. The Kolmogorov-Smirnov test was used to test variables for normality of distribution. Paired samples t-test was used for within group differences. Results: Out of 59 patients 33 eligible patients were included and randomized in an intervention (n = 17, mean±SD age 10.6±1.5 years) and control waiting list group (n = 16, mean±SD age 10.8±1.4 years). All patients completed baseline and t = 1 testing. PA significantly improved in both groups. Maximum endurance time significantly improved in the intervention but not in the control group. In a subgroup analysis for patients with low PA (intervention n = 7 and control n = 5), PA improved in the intervention but not in the control group. The intervention was safe, feasible and showed a good adherence. Conclusions: An internet-based program for children with JIA, aged 8-12 years, directed at promoting PA in daily life, effectively improves PA in those patients with low PA levels. It can also improve endurance while it is safe, feasible and has a good adherence. Implications: PA in JIA can be improved through internet based interventions. Similar programs can be developed for other chronic conditions.Purpose: The specific objectives were to: 1) describe the level of pain intensity, disability, activity limitation, kinesiophobia and physical capacity in patients with predominantly peripherally m ...