Substantiating Appropriate Motion Capture Techniques for the Assessment of Nordic Walking Gait and Posture in Older Adults

Nordic walking (NW) has become a safe and simple form of exercise in recent years, and in studying this gait pattern, various data collection techniques ...

University of Ottawa

Primary total hip arthroplasty leads to better functional capacities but a general weakness of abductor muscles often persists. A larger head component may improve the postural balance in the medial-lateral direction. The aims of this study are (1) to compare postural stability in patients after total hip and surface replacement arthroplasties and (2) to evaluate the effect of the biomechanical reconstruction on postural stability.

Postural balance during quiet standing in patients with total hip arthroplasty and surface replacement arthroplasty.

To compare gait patterns in patients with total hip arthroplasty (THA) and surface hip arthroplasty.

Gait patterns after total hip arthroplasty and surface replacement arthroplasty.

Better functional outcome is believed by some to occur after hip resurfacing (HR) than conventional 28-mm total hip arthroplasty (THA) in young and active patients with hip osteoarthritis. However, the postulated superior outcome of HR over THA may simply be the result of a bias in patient selection or the use of a larger femoral head. We therefore asked whether HR would demonstrate superior functional outcome when compared with a THA with a large-diameter femoral head in a randomized, double-blind study. Gait speed and postural balance evaluations, functional tests, and clinical data were analyzed preoperatively and at 3, 6, and 12 months after surgery. Gait speed was used as the primary outcome measure. Forty-eight patients were randomized in the study and a third group of 14 healthy subjects served as controls. The gait speed and postural balance evaluations, the performance at most functional tests, and clinical scores were similar in HR and large-head THA groups at each followup period. The operated patients reached most control group values at 3 months postoperatively. By these measures, HR did not provide better clinical function over large-head THA.

The John Charnley Award: The functional outcome of hip resurfacing and large-head THA is the same: a randomized, double-blind study.

To compare postural balance between patients who have had either a large diameter head total hip arthroplasty or surface replacement arthroplasty.

Postural balance during quiet standing in patients with total hip arthroplasty with large diameter femoral head and surface replacement arthroplasty.

Overweight (OW) and obesity (OB) are often associated with low levels of physical activity. Physical activity is recommended to reduce excess body weight, prevent body weight regain, and decrease the subsequent risks of developing metabolic and orthopedic conditions. However, the impact of OW and OB on motor function and daily living activities must be taken into account. OW and OB are associated with musculoskeletal structure changes, decreased mobility, modification of the gait pattern, and changes in the absolute and relative energy expenditures for a given activity. While changes in the gait pattern have been reported at the ankle, knee, and hip, modifications at the knee level might be the most challenging for articular integrity. This review of the literature combines concepts and aims to provide insights into the prescription of physical activity for this population. Topics covered include the repercussions of OW and OB on biomechanical and physiological responses associated with the musculoskeletal system and daily physical activity. Special attention is given to the effect of OW and OB in youth during postural (standing) and various locomotor (walking, running, and cycling) activities.

Physical activity and obesity: biomechanical and physiological key concepts.

Freezing of gait (FOG) in Parkinson's disease (PD) is challenging to measure. We asked whether a repetitive stepping in place (SIP) task on force plates could identify freezing episodes (FEs) in PD subjects, self-classified as "freezers", using the validated FOG questionnaire (FOG-Q) and whether a computerized algorithm could provide automatic detection of FEs during SIP. Thirty PD subjects and nine age-matched controls completed the SIP task. PD subjects were assessed using the Unified Parkinson's Disease Rating motor Scale (UPDRS-III) and the FOG-Q. The identification of "freezers" using the SIP task correlated with the FOG-Q (r=0.80, P<0.001). The specificity and sensitivity of identifying freezers using the SIP task reached 93% and 87%. The number and duration of FEs detected by the algorithm correlated with visual inspection (r=0.97, r=0.998, P<0.001). Freezers had larger SIP asymmetry compared to controls (P=0.02) and non-freezers (P=0.03) as well as larger arhythmicity (P=0.003 and P<0.001, respectively). UPDRS subscores were higher in freezers compared to non-freezers (P<0.05). These results suggest that the SIP task is a useful tool to detect freezing in PD and is correlated with FOG-Q. SIP cycle asymmetry and stride time variability were worse in freezers, similar to that shown in FOG studies. Detection of the number and duration of FEs using a computerized algorithm correlated with independent visual inspection of records.

Repetitive stepping in place identifies and measures freezing episodes in subjects with Parkinson's disease.

Objective. To compare center of mass (COM) compensation in the frontal and sagittal plane during gait in patients with large diameter head total hip arthroplasty (LDH-THA) and hip resurfacing (HR). Design. Observational study. Setting. Outpatient biomechanical laboratory. Participants. Two groups of 12 patients with LDH-THA and HR recruited from a larger randomized study and 11 healthy controls. Interventions. Not applicable. Main Outcome Measures. To compare the distance between the hip prosthetic joint center (HPJC) and the COM. The ratio (R(HPJC-COM)) and the variability (CV(HPJC-COM)) were compared between groups. Hip flexor, abductor, and adductor muscle strength was also correlated between groups while radiographic measurements were correlated with the outcome measures. Results. In the frontal plane, HR shows less variability than healthy controls at push-off and toe-off and R(HPJC-COM) is correlated with the muscle strength ratios (FR(ABD)) at heel contact, maximal weight acceptance, and mid stance. In the sagittal plane, LDH-THA has a higher R(HPJC-COM) than healthy controls at push-off, and CV(HPJC-COM) is significantly correlated with FR(FLEX). Conclusions. One year after surgery, both groups of patients, LDH-THA and HR, demonstrate minor compensations at some specific instant of the gait cycle, in both frontal and sagittal planes. However, their locomotion pattern is similar to the healthy controls.

Center of Mass Compensation during Gait in Hip Arthroplasty Patients: Comparison between Large Diameter Head Total Hip Arthroplasty and Hip Resurfacing.

To assess the effect of disease severity, dopaminergic medication (med) and STN-DBS on postural stability in Parkinson's disease (PD).

Effect of medication and STN-DBS on postural control in subjects with Parkinson's disease.

Freezing of gait (FOG) is associated with gait asymmetry and arrhythmicity, cognitive impairment in Parkinson's disease (PD). However, the role of postural instability (PI) in and the effect of dopaminergic medication (meds) on FOG are unclear. We investigated the effect of meds on FOG using a validated metric, Stepping in Place (SIP) and the relationship between PI and FOG.

The effect of medication and the role of postural instability in different components of freezing of gait (FOG).

Postural control in the medial-lateral (ML) direction is of particular interest regarding the assessment of changes in postural control, as it is highly related to the risk of falling.

Older adults prioritize postural stability in the anterior-posterior direction to regain balance following volitional lateral step.

To determine the effect of age on stepping performance and to compare the cognitive demand required to regulate repetitive stepping between older and younger adults while performing a stepping in place task (SIP). Fourteen younger (25.4 ± 6.5) and 15 older adults (71.0 ± 9.0) participated in this study. They performed a seated category fluency task and Stroop test, followed by a 60 s SIP task. Following this, both the cognitive and motor tasks were performed simultaneously. We assessed cognitive performance, SIP cycle duration, asymmetry, and arrhythmicity. Compared to younger adults, older adults had larger SIP arrhythmicity both as a single task and when combined with the Category (p < 0.001) and Stroop (p < 0.01) tasks. Older adults also had larger arrhythmicity when dual tasking compared to SIP alone (p < 0.001). Older adults showed greater SIP asymmetry when combined with Category (p = 0.006) and Stroop (p = 0.06) tasks. Finally, they had lower cognitive performance than younger adults in both single and dual tasks (p < 0.01). Age and type of cognitive task performed with the motor task affected different components of stepping. While SIP arrhythmicity was larger for all conditions in older compared to younger adults, cycle duration was not different, and asymmetry tended to be larger during SIP when paired with a verbal fluency task. SIP does not require a high level of control for dynamic stability, therefore demonstrating that higher-level executive function is necessary for the regulation of stepping activity independently of the regulation of postural balance. Furthermore, older adults may lack the cognitive resources needed to adequately regulate stepping activity while performing a cognitive task relying on the executive function.

Executive function is necessary for the regulation of the stepping activity when stepping in place in older adults.

To assess the effects of voluntarily reducing postural sway on postural control and to determine the attention level needed to do so in healthy adults (n=16, 65.9±9.7) and persons with PD (n=25, 65.8±9.5years). Tasks: quiet and still standing conditions with and without a category task. Cognitive performance, center of pressure (CoP) displacement variability (RMSCoP) and velocity (VCoP) were assessed in the anterior-posterior (AP) and medial-lateral (ML) directions. Controls showed larger RMSCoP (AP) and VCoP (AP and ML) during still versus quiet standing (p<0.01), while the PD group demonstrated no changes. In the PD group, RMSCoP and VCoP (ML) increased in still standing when performed with the cognitive task (p<0.05). In both groups, cognitive responses decreased in still standing (p<0.05). In PD, attempting to reduce postural sway did not affect postural control under single task conditions, however ML CoP variability and velocity did increase as a dual task. In older adults, increased displacement and velocity in both AP and ML directions was observed during single, but not dual task conditions. Therefore standing still might not be an adequate postural strategy as it increases the attentional demand and affects motor performance, putting persons with PD at greater risk for falls.

Effort to reduce postural sway affects both cognitive and motor performances in individuals with Parkinson's disease.

The aim of this study was to investigate the impact of an 8-week Nordic walking (NW) intervention on older adult gait patterns and postural alignment. Twelve healthy older adults aged 60-80 years (8 female, 4 male) participated, all performing two 6 minute walk tests (1 with poles (WP), 1 without poles (NP)) and six 5m walk trials (3 WP, 3 NP) at pre- and post-testing. Gait and postural variables were compared between poling conditions (i.e. WP to NP) as well as prior to and following the intervention. Following training, pole use resulted in various gait changes including: longer stride, faster gait, and increased power generation at the hip (H3) and power absorption at the knee (K1 and K4). We conclude that an initial 8-week training period is necessary for novice NW in order to perfect technique and to restore gait to a more natural, normal pattern following training.

Julie Nantel

School of Human Kinetics,
Faculty of Health Sciences,
School of Human Kinetics, Faculty of Health Sciences

University of Ottawa

Substantiating Appropriate Motion Capture Techniques for the Assessment of Nordic Walking Gait and Posture in Older Adults

Julie Nantel

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University of Ottawa

Substantiating Appropriate Motion Capture Techniques for the Assessment of Nordic Walking Gait and Posture in Older Adults

School of Human Kinetics,
Faculty of Health Sciences,
School of Human Kinetics, Faculty of Health Sciences