Influence of cognitive and motor tasks using smartphone during gait: EMG and gait performance analysis – Dual-task study

Previous studies reported changes in spatiotemporal gait parameters during dual-task performance while walking using a smartphone compared to walking without a smartphone. However, studies that assess muscle activity while walking and simultaneously performing smartphone tasks are scarce. So, this study aimed to assess the effects of motor and cognitive tasks using a smartphone while simultaneously performing gait on muscle activity and gait spatiotemporal parameters in healthy young adults. Thirty young adults (22.83 ± 3.92 years) performed five tasks: walking without a smartphone (single-task, ST); typing on a smartphone keyboard in a sitting position (secondary motor single-task); performing a cognitive task on a smartphone in a sitting position (cognitive single-task); walking while typing on a smartphone keyboard (motor dual-task, mot-DT) and walking while performing a cognitive task on a smartphone (cognitive dual-task, cog-DT). Gait speed, stride length, stride width and cycle time were collected using an optical motion capture system coupled with two force plates. Muscle activity was recorded using surface electromyographic signals from bilateral biceps femoris, rectus femoris, tibialis anterior, gastrocnemius medialis, gastrocnemius lateralis, gluteus maximus and lumbar erector spinae. Results showed a decrease in stride length and gait speed from the single-task to cog-DT and mot-DT (p < 0.05). On the other hand, muscle activity increased in most muscles analyzed from single- to dual-task conditions (p < 0.05). In conclusion, performing a cognitive or motor task using a smartphone while walking promote a decline in spatiotemporal gait parameters performance and change muscle activity pattern compared to normal walking.     

Contributions of trunk muscles to anticipatory postural control in children with and without developmental coordination disorder

Current evidence suggests that movement quality is impacted by postural adjustments made in advance of planned movement. The trunk inevitably plays a key role in these adjustments, by creating a stable foundation for limb movement. The purpose of this study was to examine anticipatory trunk muscle activity during functional tasks in children with and without developmental coordination disorder (DCD). Eleven children with DCD (age 7 to 14 years) and 11 age-matched, typically-developing children performed three tasks: kicking a ball, climbing stairs, and single leg balance. Surface electromyography (EMG) was used to examine the neuromuscular activity of bilateral transversus abdominis/internal oblique, external oblique and L3/4 erector spinae, as well as the right tibialis anterior and rectus femoris muscles. Onset latencies for each muscle were calculated relative to the onset of rectus femoris activity. In comparison to the children with DCD, the typically-developing children demonstrated earlier onsets for right tibialis anterior, bilateral external oblique, and right transversus abdominis/internal oblique muscles. These results suggest that anticipatory postural adjustments may be associated with movement problems in children with DCD, and that timing of both proximal and distal muscles should be considered when designing intervention programs for children with DCD.     

Smaller muscle mass is associated with increase in EMG–EMG coherence of the leg muscle during unipedal stance in elderly adults

Age-induced decline in the ability to perform daily activities is associated with a deterioration of physical parameters. Changes occur in neuromuscular system with age; however, the relationship between these changes and physical parameters has not been fully elucidated. Therefore, in this study, we aimed to determine the relationship between neuromuscular system evaluated using a coherence analysis of the leg muscles and physical parameters in community-dwelling healthy elderly adults. The participants were required to stand still in bipedal and unipedal stances on a force plate. Then, electromyography (EMG) was recorded from the tibialis anterior (TA) and medial and lateral gastrocnemius (MG/LG) muscles, and intermuscular coherence was calculated between the following pairs: TA and MG (TA–MG), TA and LG (TA–LG), and MG and LG (MG–LG). Furthermore, gait speed, unipedal stance time, and muscle mass were measured. EMG–EMG coherence for the MG–LG pair was significantly greater in the unipedal stance task than in the bipedal one (p = .001). Multiple linear regression analysis revealed that the muscle mass of the leg was negatively correlated with the change in the β-band coherence for the MG–LG pair from bipedal to unipedal stance (R² = 0.067, standard β = −0.345, p = .044). As the β-band coherence could reflect the corticospinal activity, the increased β-band coherence may be a compensation for the smaller muscle mass, or alternatively may be a sign of changes in the nervous system resulting in the loss of muscle mass.     

Influence of wearing an unstable shoe construction on compensatory control of posture

This study investigated the influence of wearing unstable shoe construction (WUS) on compensatory postural adjustments (CPA) associated with external perturbations. Thirty-two subjects stood on a force platform resisting an anterior-posterior horizontal force applied to a pelvic belt via a cable, which was suddenly released. They stood under two conditions: barefoot and WUS. The electromyographic (EMG) activity of gastrocnemius medialis, tibialis anterior, rectus femoris, biceps femoris, rectus abdominis, and erector spinae muscles and the center of pressure (CoP) displacement were acquired to study CPA. The EMG signal was used to assess individual muscle activity and latency, antagonist co-activation and reciprocal activation at joint and muscle group levels. Compared to barefoot, WUS led to: (1) increased gastrocnemius medialis activity, (2) increased total agonist activity, (3) decreased antagonist co-activation at the ankle joint and muscle group levels, (4) increased reciprocal activation at the ankle joint and muscle group levels, and (5) decrease in all muscle latencies. No differences were observed in CoP displacement between conditions. These findings demonstrate that WUS led to a reorganization of the postural control system associated to improved performance of some components of postural control responses.     

Functioning of peripheral Ia pathways in leg muscles of newly walking toddlers

Monosynaptic and polysynaptic spinal level reflexes in the leg muscles of infants show significant dispersion across muscles, high variability, and no change in response patterns over the first 10 months. Here we tested the hypothesized relation between early walking experience and the tuning of these responses in three primary gait muscles of participants in four subgroups: cruisers (n = 7) and toddlers with one (n = 5), two (n = 5), or three (n = 5) months of walking experience. Reflex responses in multiple Ia pathways – tendon reflex (T-reflex), vibration-induced inhibition of the T-reflex (VIM-T-reflex), and tonic vibration-induced reflex (VIR), were elicited by mechanical stimuli applied to the distal tendons of the quadriceps, gastrocnemius-soleus, and tibialis anterior of both legs. Walking skill was assessed via a GAITRite mat. Generally, walking experience seemed to be related to slowly emerging improvements and, depending on muscle tested and pathway, progress was quite varied. Amplitude and latency of reflex responses were more clearly impacted by age or leg length while the ratio or distribution pattern of reflex response among antagonist pairs of muscles was impacted by walking experience and skill. As walking experience increased, the ratio of reflex responses tended to increase for the stimulated and decrease for the antagonist reflex loops with distribution of the pattern shifting gradually toward a single type of reflex response in all tested muscles. The very slow tuning of these reflexes may underlie the many missteps and falls reported to occur during early walking and suggest that subsequent studies should continue to follow the developmental trajectory through the first year of walking experience.     

Impact of lumbar spine posture on thoracic spine motion and muscle activation patterns

Complex motion during standing is typical in daily living and requires movement of both the thoracic and lumbar spine; however, the effects of lumbar spine posture on thoracic spine motion patterns remain unclear. Thirteen males moved to six positions involving different lumbar (neutral and flexed) and thoracic (flexed and twisted) posture combinations. The thoracic spine was partitioned into three segments and the range of motion from each posture was calculated. Electromyographical data were collected from eight muscles bilaterally. Results showed that with a flexed lumbar spine, the lower-thoracic region had 14.83° and 15.61° more flexion than the upper- and mid-thoracic regions, respectively. A flexed lumbar spine significantly reduced the mid-thoracic axial twist angle by 5.21° compared to maximum twist in the mid-thoracic region. Functional differences emerged across muscles, as low back musculature was greatest in maintaining flexed lumbar postures, while thoracic erector spinae and abdominals showed bilateral differences with greater activations to the ipsilateral side. Combined postures have been previously identified as potential injury modulators and bilateral muscle patterns can have an effect on loading pathways. Overall, changes in thoracic motion were modified by lumbar spine posture, highlighting the importance of considering a multi-segmented approach when analyzing trunk motion.     

Motivational,volitional and multiple goal predictors of walking in people with type 2 diabetes

BackgroundType 2 diabetes is a major public health problem. Effective diabetes self-management involves people engaging in multiple health behaviours, including physical activity. Walking is an effective, accessible and inexpensive form of physical activity, yet many people with Type 2 diabetes do not meet recommended levels. The present study aimed to: 1) identify demographic, motivational and volitional factors predictive of walking in people with Type 2 diabetes mellitus, and 2) test whether accounting for the perceived impact of other goal pursuits (goal facilitation and goal conflict) improved the prediction of walking.MethodsA theory-based cross-sectional study using the Health Action Process Approach was conducted in adults with Type 2 diabetes across Scotland. Assuming a 50% response rate 1000 questionnaires were mailed to achieve the target sample size (N = 500). Demographic information was collected, and intentional (outcome expectations, social support, risk perceptions), motivational (intention, self-efficacy), volitional (action planning, action control) and multiple goal (goal conflict, goal facilitation) factors were assessed as predictors of physical activity in general and walking specifically.ResultsThe final sample comprised 411 respondents. The majority (60%) were non-adherent to physical activity recommendations. Of 411 respondents, 356 provided walking data. Body Mass Index and age were the only demographic and anthropometric factors predictive of walking (overall R² = 0.04). When motivational factors were added, intention and self-efficacy added to the prediction (overall R² = 0.07). When volitional factors were added, only action control was predictive of walking (overall R² = 0.08). Finally, goal facilitation explained an additional 7% variance in walking when added to the model (final overall R² = 0.15).ConclusionThere was low adherence with physical activity recommendations in general and walking in particular. When testing predictors of motivational, volitional and competing goal constructs together, action control and goal facilitation emerged as predictors of walking. Future research should consider how walking can be embedded synergistically alongside other goal pursuits and how action control may help to ensure that they are pursued.     

Deep and superficial cervical muscles respond differently to unstable motor skill tasks

Biomechanical modelling and physiological studies suggest that various spinal muscle layers differ in their contribution to spine movement and stiffness. This study aimed to investigate the activation of deep and superficial muscles in stable and unstable task conditions. Nine healthy participants performed a task of controlling a metal ball on a plate fixed to the head in seated position. In unstable tasks, visual feedback was provided by mirrors to move the ball to the centre of the plate by small head movements and maintain the position for 3 s. Task difficulty was adjusted in a stepwise progression of difficulty using five surfaces with materials of decreasing resistance. In the stable condition, the ball was fixed to the plate's centre. EMG was recorded with surface (sternocleidomastoid, anterior scalenes, upper trapezius) and fine-wire electrodes (rectus capitis posterior major, obliquus inferior, multifidus, semispinalis cervicis, splenius capitis). The outcome variable was root mean square (RMS) EMG during the part of the task when the ball was maintained in the centre position. Results revealed greater cervical muscle activity in the unstable than stable conditions (p < 0.001, η_p² = 0.746). Control of deep and superficial cervical muscles differed (p = 0.003, η_p² = 0.354). Deep cervical muscle activity was greater with unstable tasks, but did not differ with task difficulty. In contrast, superficial cervical muscle activity increased in a stepwise manner with increasing challenge. These results support the notion that the central nervous system uses different strategies for control of deep versus superficial muscle layers of the cervical spine in association with instability.     

EMG and kinematics analysis of the trunk and lower extremity during the sit-to-stand task while wearing shoes with different heel heights in healthy young women

This study investigated the EMG characteristics and the kinematics of the trunk and lower extremity during the sit-to-stand (STS) task while wearing 1-, 4-, and 8-cm high-heeled shoes. We examined differences in the EMG data of the internal oblique, erector spinae, medial hamstring, and rectus femoris muscles during the STS task. The motion of the hip joint during an STS task was measured with a NorAngle Electrogoniometer System. Twelve young healthy women were recruited to this study. EMG characteristics and the hip joint angle were recorded during the performance of an STS task by subjects wearing high-heeled shoes of three different heel heights. The muscle onset time and EMG activity during this task were analyzed. In 8-cm high-heeled shoes, the onset time for the erector spinae muscle was significantly delayed, and the onset latency for the medial hamstring and the rectus femoris was significantly decreased. There was increased activity in the erector spinae and rectus femoris muscle during this task when wearing 8-cm high-heeled shoes. The initial hip flexion angle at the start point of the STS task did not differ among the 1-, 4-, and 8-cm heel-height conditions, but the trunk flexion angle, corresponding to the displacement between the peak hip flexion and initial hip flexion, was significantly larger in the 8-cm heel-height condition than in the 1- and 4-cm heel-height conditions. The findings suggest that excessive heel height has the potential to induce muscle imbalance during the STS task.     

Muscle coordination patterns in regulation of medial gastrocnemius activation during walking

The ankle plantar flexion in the late stance phase is referred to as the ankle push-off. When the ankle push-off force is enhanced, compensatory adjustments occur in the adjacent phases. The muscle control that achieves these compensatory movements remains unknown, although they are expected to be coordinately regulated across multiple muscles and phases. Muscle synergy is used as a quantification technique for muscle coordination, and this analysis enables the comparison of synchronized activity between multiple muscles. Therefore, this study aimed to elucidate the tuning of muscle synergies in muscle activation adjustment of push-off. It is hypothesized that muscle activation adjustment of push-off is performed in the muscle synergy related to ankle push-off and in the muscle synergy that activates during the adjacent push-off phase. Eleven healthy men participated, and participants manipulated the activity of the medial gastrocnemius during walking through visual feedback. Two conditions were compared as experimental conditions: increasing the muscle activity to 1.6 times that during normal walking (High) and matching it with that during normal walking (Normal). Twelve muscle activities in the trunk and lower limb and kinematic data were recorded. Muscle synergies were extracted by the non-negative matrix factorization. No significant difference was observed in the number of synergies (High: 3.5 ± 0.8, Normal: 3.7 ± 0.9, p = 0.21) and muscle synergy activation timing and duration between the High and Normal conditions (p > 0.27). However, significant differences were observed in the peak muscle activity during the late stance phase of the rectus femoris (RF), biceps femoris (BF) between conditions (RF at High: 0.32 ± 0.21, RF at Normal: 0.45 ± 0.17, p = 0.02; BF at High: 0.16 ± 0.01, BF at Normal: 0.08 ± 0.06 p = 0.02). Although the quantification of force exertion has not been conducted, the modulation of RF and BF activation could have occurred due to the attempts to help knee flexion. Muscle synergies during normal walking are therefore maintained, and slight adjustments in the amplitude of muscle activity occurred for each muscle.     

Slipping during side-step cutting: Anticipatory effects and familiarization

The aim of the present study was to verify whether the expectation of perturbations while performing side-step cutting manoeuvres influences lower limb EMG activity, heel kinematics and ground reaction forces. Eighteen healthy men performed two sets of 90° side-step cutting manoeuvres. In the first set, 10 unperturbed trials (Base) were performed while stepping over a moveable force platform. In the second set, subjects were informed about the random possibility of perturbations to balance throughout 32 trials, of which eight were perturbed (Pert, 10 cm translation triggered at initial contact), and the others were “catch” trials (Catch). Center of mass velocity (CoM_VEL), heel acceleration (H_AC), ground reaction forces (GRF) and surface electromyography (EMG) from lower limb and trunk muscles were recorded for each trial. Surface EMG was analyzed prior to initial contact (PRE), during load acceptance (LA) and propulsion (PRP) periods of the stance phase. In addition, hamstrings-quadriceps co-contraction ratios (CCR) were calculated for these time-windows. The results showed no changes in CoM_VEL, H_AC, peak GRF and surface EMG PRE among conditions. However, during LA, there were increases in tibialis anterior EMG (30–50%) concomitant to reduced EMG for quadriceps muscles, gluteus and rectus abdominis for Catch and Pert conditions (15–40%). In addition, quadriceps EMG was still reduced during PRP (p < .05). Consequently, CCR was greater for Catch and Pert in comparison to Base (p < .05). These results suggest that there is modulation of muscle activity towards anticipating potential instability in the lower limb joints and assure safety to complete the task.     

Effect of psychostimulant medications on static balance performance in adults with attention deficit hyperactivity disorder: Within-subjects repeated-measure study

ObjectiveThis study examined the effect of psychostimulant medications nPS) on balance and functional motor performance in adults with attention-deficit/hyperactivity disorder (ADHD).MethodsParticipants completed two sessions (off-medication and on-medication) in a within-subjects repeated-measure study design. There was a minimum of seven days between the two sessions. During both sessions, participants stood for 30 s per condition on a force platform. The conditions were: feet-apart with 1) eyes-open and 2) eyes-closed; feet-together with 3) eyes-open and 4) eyes-closed. Participants performed three trials of timed up and go (TUG) and lateral step-up test (LSUT) during both sessions. Outcome measures were sway area (SA [cm²]), average sway velocity (SV [cm/s]), TUG average time (s), and average number of LSUT repetitions. Data were analyzed using multivariate repeated measures analysis of variance and paired t-tests for examining PS effects on balance (SA and SV) and functional motor performance (TUG and LSUT), respectively.ResultsThe sample included 45 adults (35 females; mean age = 28.4 ± 6.3 years). The repeated-measures MANOVA indicated that PS was associated with better SA [F(1,44) = 9.6; p = 0.003;η_p² = 0.18] but not with SV [F(1,44) = 1.0; p = 0.319;η_p² = 0.02]. PS was associated with significantly better SA with decreasing base-of-support [F(1,44) = 9.9; p = 0.003;η_p² = 0.18]. Additionally, PS use was associated with better TUG [t(1,44) = 2.65; p = 0.014;Cohen's d = 0.39] but not LSUT performances [t(1,44) = −0.68; p = 0.499;Cohen's d = −0.10].ConclusionsPS was associated with better SA and TUG in adults with ADHD. Further studies are needed to investigate the effects of PS on balance performance using rigorous designs in this population.ImpactHealthcare providers should screen for PS status and balance when treating adults with ADHD to enhance safe motor performance.     

Detecting motorcycle rider local physical fatigue and discomfort using surface electromyography and seat interface pressure

Whilst motorcycling is an activity of pleasure in most parts of the world, in India it is a regular mode of commuting. Incidence of fatigue is substantially higher among motorcycle riders than drivers of other modes of transport. The objective of this study was to detect physical fatigue due to motorcycle riding for an hour using surface electromyography (sEMG) and seat interface pressure. Twenty healthy male participants performed 60 min of motorcycle riding in a low traffic density environment. Muscle activity was recorded bilaterally from extensor carpi radialis (ECR), biceps brachii (BB), trapezius medial (TM), sternocleldomastoid (S) latissimus dorsi (LD) and erector spinae (ES) muscle groups. Interface seat pressure distribution was monitored using a pressure mapping system. Results showed that participants have significant (p < 0.05) physical fatigue in TM, LD and ES muscle groups during 60 min of motorcycle riding. Seat pressure distribution was found to be non-uniform during the course of motorcycling. Results suggest that the impact on local physical fatigue and seat discomfort are probably due to static seating demand and prolonged sitting posture balance required to ride the motorcycle for an hour.     

Measures of postural control and mobility during dual-tasking as candidate markers of instability in Huntington's disease

BackgroundIndividuals with Huntington's disease (HD) have impairments in performing dual-tasks, however, there is limited information about the effects of changing postural and cognitive demands as well as which measures are best suited as markers of underlying motor-cognitive interference.MethodsForty-three individuals with HD and 15 healthy controls (HC) completed single tasks of walking (Timed Up & Go (TUG), 7 m walk), standing (feet together, feet apart and foam surface) and seated cognitive performance (Stroop, Symbol Digit Modalities Test (SDMT), Delis-Kaplan Executive Function System (DKEFS) Sorting test) and dual cognitive-motor tasks while standing (+ Stroop) and walking (+ DKEFS, TUG cognitive). APDM Opal sensors recorded measures of postural sway and time to complete motor tasks.ResultsIndividuals with HD had a greater increase in standing postural sway compared to HC from single to dual-tasks and with changes to support surface. Both groups demonstrated a decrease in gait performance during the TUG cognitive, however, this difference was greater in people with HD compared to HC. While those with HD showed a greater dual-task motor cost compared to HC, both groups behaved similarly as condition complexity increased.ConclusionsStanding postural sway is a more sensitive marker of instability than change in standard gait speed, particularly under dual-task conditions. The more complex TUG cognitive is a sensitive measure of walking dual-task performance. The results of this study provide insights about the nature of motor-cognitive impairments in HD and provide support for a distinction between static and dynamic postural control mechanisms during performance of dual-tasks.     

Bilateral asymmetry of running gait in competitive,recreational and novice runners at different speeds

The mechanisms and underlying causes of bilateral asymmetry among healthy runners of different levels remain unclear. This cross-sectional laboratory study aimed to investigate the effects of running speed and running experience or competitive level on bilateral symmetry during running. Eleven competitive runners, 9 recreational runners and 11 novice runners were recruited in this study. They ran on an instrumented treadmill for 3 min at each of 5 fixed speeds (8, 9, 10, 11 and 12 km/h) in a randomized order. Bilateral asymmetry was evaluated and quantified using symmetry index (SI) of temporal and kinetic parameters. Overall, SI ranged between 0.8% for stride time and 21.4% for vertical average loading rate. Significant speed effects were observed on SI of flight time (p = .012), which was significantly higher at 8 km/h than that of the other 4 speeds (p = .023, 0.005, 0.023 and 0.028, respectively). Group-by-speed interactions were detected on SI in time to peak vertical ground reaction force (p = .032) and vertical average loading rate (p = .002). The competitive runners presented linear reduction in the SI with increasing speed from 8 to 12 km/h (R² > 0.94); for the recreational runners, SI changed nonlinearly and presented a roughly U-shaped trend across speeds (R² > 0.88); and for the novice runners, changes of SI across speed were inconsistent and dependent on parameters of interest (R² > 0.64). Bilateral asymmetry was affected by both running speed and runners' running experience or competitive level. The competitive runners were found to run with a more symmetrical manner with a greater running speed, the recreational runners demonstrated the most symmetrical pattern at the critical speed, whereas the novice runners showed inconsistent trends.     

The pendular mechanism does not determine the optimal speed of loaded walking on gradients

The pendular mechanism does not act as a primary mechanism in uphill walking due to the monotonic behavior of the mechanical energies of the center of mass. Nevertheless, recent evidence shows that there is an important minimization of energy expenditure by the pendular mechanism during walking on uphill gradients. In this study, we analyzed the optimum speed (OPT) of loaded human walking and the pendulum-like determining variables (Recovery R, Instantaneous pendular re-conversion R_int, and Congruity percentage %Cong). Ten young men walked on a treadmill at five different speeds and at three different treadmill incline gradients (0, +7 and +15%), with and without a load carried in their backpacks. We used indirect calorimetry and 3D motion analysis, and all of the data were analyzed by computational algorithms. R_int increased at higher speeds and decreased with increasing gradient. R and %Cong decreased with increasing gradient and increased with speed, independent of load. Thus, energy conversion by the pendular mechanism during walking on a 15% gradient is supported, and although this mechanism can explain the maintenance of OPT at low walking speeds, the pendular mechanism does not fully explain the energy minimization at higher speeds.     

How does normal variability in trunk flexion affect lower limb muscle activity during walking?

A large proportion of the mass of the body is contained within the trunk segment. Therefore, small changes in the inclination of this segment have the potential to influence the direction of the ground reaction force and alter lower limb joint moments and muscle activation patterns during walking. The aim of this study was to investigate if variability in sagittal trunk inclination in healthy participants is associated with differences in lower limb biomechanics. Gait analysis data was collected on 41 healthy participants during walking. Two groups were defined based on habitual trunk flexion angle during normal walking, a forward lean group (n = 18) and a backward lean group (n = 17). Lower limb moments, muscle activation patterns and co-contraction levels were compared between the two groups using independent t-tests. The forward lean group walked with 5° more trunk flexion than the backward lean group. This difference was associated with a larger peak hip moment (effect size = 0.7) and higher activation of the lateral gastrocnemius (effect size =0.6) and the biceps femoris (effect size =0.7) muscles. The forward lean group also exhibited greater co-contraction in late stance (effect size =0.7). This is the first study to demonstrate that small differences in trunk flexion are associated with pronounced alterations in the activation of the lateral knee flexor muscles. This is important because people with knee osteoarthritis have been observed to walk with increased trunk flexion. It is possible that increased sagittal trunk inclination may be associated with elevated joint loads in people with knee osteoarthritis.     

The predictive relationships between advanced dynamic balance and physical activity/quality of life in Parkinson's disease

Gait and balance problems commonly occur in Parkinson's disease (PD). However, balance tasks with only one performance objective (e.g., sit-to-stand) may not be sufficient, compared to dual motor tasks (e.g., carrying a tray while walking), to be applied to the assessments and interventions which are designed to promote PD patients' balance functioning, physical activity (PA) and health-related quality of life (HQoL). The aim of this study, therefore, was to determine whether advanced dynamic balance, measured by a demanding motor-motor dual task, is a significant predictor of PA/HQoL in older adults with and without PD. Participants with (n = 22) and without (n = 23) PD were assessed using the Berg Balance Scale (BBS), the single leg hop and stick series task (SLHS), the Physical Activity Scale for the Elderly (PASE), and the Parkinson's Disease Questionnaire–39 (PDQ39). We calculated the R² change, namely the incremental validity, between the multiple regression models before and after adding the scores on the BBS/SLHS. While controlling for biological and socioeconomic covariates, competence in the SLHS task provided moderate and large levels of incremental validity to PA (ΔR² = 0.08, Cohen's f² = 0.25, p = .035) and HQoL (ΔR² = 0.13, Cohen's f² = 0.65, p < .001), respectively. In particular for participants with PD, the SLHS explained significantly more variance in HQoL in relation to psychosocial functioning (ΔR² = 0.25, Cohen's f² = 0.42, p = .028) compared to the BBS (p = .296). Assessing advanced dynamic balance by means of a highly demanding dual-task paradigm was not only strongly associated with PA but also covered a wider spectrum of HQoL components. This approach is recommended for use in evaluations and interventions carried out in clinical and research settings in order to promote healthy living.     

Are there common walking gait characteristics in patients diagnosed with late-onset Pompe disease?

Late-onset Pompe disease (LOPD) is a rare disease, defined as a progressive accumulation of lysosomal glycogen resulting in muscle weakness and respiratory problems. Anecdotally, individuals often have difficulties walking, yet, there is no three-dimensional data supporting these claims. We aimed to assess walking patterns in individuals with LOPD and compare with healthy individuals. Kinematic, kinetic and spatiotemporal data were compared during walking at a self-selected speed between individuals with LOPD (n = 12) and healthy controls (n = 12). Gait profile scores and movement analysis profiles were also determined to indicate gait quality. In comparison with healthy individuals, the LOPD group demonstrated greater thoracic sway (96%), hip adduction angles (56%) and pelvic range of motion (77%) and reduced hip extensor moments (36%). Greater group variance for the LOPD group were also observed. Individuals with LOPD had a slower (15%) walking speed and reduced cadence (7%). Gait profile scores were 37% greater in the LOPD group compared to the healthy group. Proximal muscular weakness associated with LOPD disease is likely to have resulted in a myopathic gait pattern, slower selected walking speeds and deviations in gait patterns. Although individuals with LOPD presented with some common characteristics, greater variability in gait patterns is likely to be a result of wide variability in phenotype spectrum observed with LOPD. This is the first study to examine walking in individuals with LOPD using instrumented gait analysis and provides an understanding of LOPD on walking function which can help orientate physiotherapy treatment for individuals with LOPD.     

Sex differences in the impact of state and trait fatigue on gait variability

Conditions requiring greater attention or cognitive control, such as fatigue, lead to changes in the motor performance of a task. Perceived fatigue refers to subjective feelings of fatigue, can be expressed as a state variable or trait characteristic and is influenced by demographic factors, such as sex. The purpose of this study was to determine how sex interacts with state and trait physical fatigue (PF) and mental fatigue (MF) to influence gait variability. METHODS: 123 healthy adults (77 female, 46 male), aged 18–36 years, completed the Mental and Physical State and Trait Energy and Fatigue Scale. Using a median split for each fatigue variable, participants were placed into “low” or “high” fatigue categories. Gait variability was defined as the asymmetry of lateral step variability (ALSV) and coefficient of variation (CV) of gait speed, stride length and double limb (DL) support during overground walking. RESULTS: Males with low state PF had greater ALSV than females with low state PF (p = 0.05, η²_p = 0.07) and males with high state PF (p = 0.007, η²_p = 0.15). Females with high trait MF had greater CV of gait speed than females with low trait mental fatigue (p = 0.02, η²_p = 0.08). Males with low trait MF had greater CV of gait speed (p = 0.01, η²_p = 0.10) and stride length (p = 0.002, η²_p = 0.17) than females with low trait MF. CV of DL support did not vary based on fatigue level or sex (p ≥ 0.11). CONCLUSIONS: There are sex-specific differences in the impact of state PF on asymmetry of lateral step variability and trait MF on the variability of gait speed and stride length.