The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty four elite level female hockey players performed each technique while standing on a ground mounted force platform, all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two significantly distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The mediolateral arm swing produced 37% greater frontal plane and 33% lesser sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques however the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more consistent with the direction of lower limb propulsion, perhaps resulting in a greater contribution to high velocity skating. Based on the findings from the present study ice hockey skaters should perform the mediolateral arm swing to maximize the effective GRFs produced with each stride.

The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty four elite level female hockey players performed each technique while standing on a ground mounted force platform, all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two significantly distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The mediolateral arm swing produced 37% greater frontal plane and 33% lesser sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques however the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more consistent with the direction of lower limb propulsion, perhaps resulting in a greater contribution to high velocity skating. Based on the findings from the present study ice hockey skaters should perform the mediolateral arm swing to maximize the effective GRFs produced with each stride.

Introduction: Idiopathic Parkinson’s Disease is a multisystem neurodegenerative disease that is characterized by asymmetric impairment in regions of the midbrain, forebrain, and brainstem. Of the known neurodegenerative diseases, Parkinson’s is the second most commonly diagnosed worldwide with a global prevalence expected to reach 9 million individuals by 2030. As fall rates range between 35-68% annually, falling during walking is amongst the primary concerns for this demographic. Interestingly, despite the close association between loss of arm swing (due to Parkinson’s Disease) and future falls, evidence to-date has not examined the effect different arm swing conditions have on walking stability during unperturbed and perturbed (cognitive and mechanical) conditions. Dynamic stability research in this demographic is further limited in that evidence examining differences between the least and most affected leg is sparse. Research Objectives: To examine the differences between natural arm swing (unrestricted) and when arm swing was physical restricted (restricted) in people with Parkinson’s Disease. The effect of arm swing was assessed when people with Parkinson’s Disease walked in steady-state, dual-task, destabilizing terrains as well as in response to slips. Additionally, this thesis examined differences between the least and most affected sides, during the aforementioned conditions, that stem from the asymmetric progression in Parkinson’s Disease. Methods: Twenty individuals with Parkinson’s Disease were recruited for this research. Individuals walked on a CAREN-Extended System with unrestricted (natural) and restricted (absent) arm swing. Arm conditions were combined with steady-state walking, walking while performing a secondary dual-task, walking on minor destabilizing environments (hilly, rocky and mediolateral translational), and in response to slips for the heel-strikes of the perturbed (slipped) leg and recovery (contralateral) leg. The minor destabilizing terrains were assessed separately to steady-state walking for the arm swing condition resulting in three types of analyses (arms-rocky, arms-rolling hills, and arms-mediolateral). Data were processed in Vicon, Visual 3D, and OpenSim before being exported to Matlab to calculate dynamic stability (Margin of Stability, Harmonic Ratios and Coefficient of Variation), average spatiotemporal parameters, as well as trunk linear and angular velocities. Statistical analyses were conducted in SPSS with a significance level set a priori at (p<0.05). Results: During unperturbed walking with the restricted arm swing condition, compared to unrestricted, average trunk angular velocity increased in the transverse plane while instantaneous linear velocity at heel-strike decreased in the sagittal plane. Further, on the least affected leg, the Margin of Stability increased, average step length decreased, and coefficient of variation for step length increased. Contrastingly, step time coefficient of variation increased in the most affected leg. In the presence of the dual-task, average angular velocity in the frontal plane increased, average step time decreased (most affected leg), and step width coefficient of variation increased (bilaterally). Compared to unrestricted arm swing, restricted arm swing reduced average step length (arm-rolling hills) and time (arm-rocky), and increased COV step time (arm-rolling hills). The arm-rolling hills analysis revealed that the most affected leg had a shorter step length than the least affected. The destabilizing surface effects revealed that during the arm-rolling hills and arm-rocky analyses step time decreased, step width increased, and the COV for step time, length and width increased. No main effects occurred for the arm-mediolateral analysis. Additionally, when comparing the arm swing conditions in response to a slip, the restricted arm swing condition, compared to unrestricted, caused a faster step time during the slipped step. Compared to the most affected leg, the least affected had a wider step width during the slipped step. During the recovery step, the least affected leg had a larger anteroposterior Margin of Stability and longer step time than the most affected. Conclusion: The findings revealed that when people with Parkinson’s Disease walk without arm swing, trunk rotational velocity increases which internally perturbs gait. This destabilization elicited unique responses from dynamic stability metrics that were specific to the terrain encountered. Since Parkinson’s Disease primarily affects movement timing, the results suggest that loss of arm swing is particularly perturbing to foot placement timing while changes in spatial foot placement reflect compensation to maintain an existing level of global dynamic stability and symmetry. Additionally, the evidence indicates that the independent behavior of the least and most affected leg respond uniquely to loss of arm swing. However, as people with Parkinson’s Disease adjust the least affected leg’s foot placement to mirror the contralateral leg, functional interlimb differences may only be revealed when individuals encounter perturbations.

Movement problems related to Parkinson’s disease (PD) have been shown to have a profound effect on functional independence and reported quality of life. Within the constellation of movement signs of PD (tremor, muscle rigidity, bradykinesia/hypokinesia, and postural instability), impaired arm swing is often the earliest-recognized symptom. It is also a strong independent predictor of greater fall risk and morbidity/mortality risk. Early treatment for movement problems such as impaired arm swing is associated with the greatest improvement in these impairments. However, movement problems often coincide with impaired processing of sensory information, leaving many people with PD with inadequate awareness of their posture and limb position. Thus, PD-related gait deficits are difficult for people to correct by themselves. External cueing techniques (such as visual cues in the environment or auditory cues for pacing and rhythm) have shown promise in improving parameters such as gait speed, s / Kinesiology

Mulheres submetidas à mastectomia, apresentam assimetrias posturais, assim como alterações na cinemática do movimento do ombro e tronco. O objetivo deste estudo foi avaliar o equilíbrio estático bem como a marcha em mulheres submetidas à cirurgia de mastectomia unilateral. Para tanto, foram analisadas 42 mulheres, divididas em dois grupos: mulheres submetidas à mastectomia unilateral (GM), com idade média de 53,77±7,24 anos, e mulheres sem a doença como controle (GC), com idade média de 54,70±6,31 anos. As análises do equilíbrio estático e da marcha foram efetuadas com sistema Vicon System (VICON-MX-T40S, Oxford, Inglaterra). Foi avaliado o equilíbrio estático com olhos abertos e olhos fechados, com e sem o uso da prótese mamária externa, por meio da área e do deslocamento do centro de massa projetado no chão, assim como o ângulo da coluna. Na marcha, foram avaliados os parâmetros espaço-temporal com e sem o uso da prótese mamária externa, e a oscilação dos membros superiores e do tronco. Foi aplicado o teste de normalidade de Shapiro-Wilk, diante de uma distribuição normal e relacionada, aplicou-se o teste T relacionado, e para amostras independentes, teste T independente, em distribuição não paramétrica, foi aplicado Wilcoxon para variáveis relacionadas e Mann-Whitney, para variáveis independentes. Foi fixado o nível crítico de 5% (p<0,05), o processamento dos dados efetuado pelo software SPSS, versão 17.0. A análise do equilíbrio estático apontou aumento significativo na área e no deslocamento do centro de massa projetado no chão, e deslocamento médio-lateral do ângulo da coluna. Na marcha, houve piora dos parâmetros espaço-temporal e menor oscilção do membro superior homolateral à cirurgia para movimentos de flexão/extensão e abdução/adução, o tronco apresentou menor oscilação médio-lateral. A prótese parece não ter influenciado no equilíbrio e na marcha. Os resultados sugerem que a mastectomia unilateral pode afetar o equilíbrio e a marcha. / Women undergoing mastectomy, have postural asymmetries as well as changes in the kinematics of the movement of the shoulder and spine. The objective of this study was to evaluate static balance and gait in women undergoing unilateral mastectomy surgery. Therefore, 42 women were analyzed, divided into two groups: women who underwent unilateral mastectomy (GM) with a mean age of 53.77 ± 7.24 years, and women without the disease as control (GC) with a mean age of 54.70 ± 6.31 years. Analyses of static equilibrium and gait was performed with Vicon System (MX-T40S-VICON, Oxford, England). We evaluated the static balance with eyes open and eyes closed, with and without the use of external breast prosthesis through the area and the center of mass displacement designed on the floor, as well as the angle of the spine. On the gait were evaluated spatiotemporal parameters with and without the use of external breast prosthesis and the oscillation of the upper limbs and trunk during walking. The functionality of the upper limbs was measured by the DASH questionnaire, and the level of physical activity by IPAQ. We used the Shapiro-Wilk normality test, before a normal and related distribution, we applied the related t test for independent samples and, independent t test, in non-parametric distribution, Wilcoxon was applied to related variables and Mann Whitney test for independent variables was set the critical level of 5% (p <0.05), the processing of data carried out by SPSS software, version 17.0. The static equilibrium analysis indicated a significant increase in the area and the center of mass offset projected on the ground and the medial-lateral displacement of the spine angle. On the march, there was worsening of spatiotemporal parameters and lower swing in arm ipsilateral to surgery for flexion/extension and abduction/adduction, trunk shows less medial-lateral oscillation. The prosthesis seems to have no influence on balance and gait. The results suggest that unilateral mastectomy can affect the balance and gait.

Mulheres submetidas à mastectomia, apresentam assimetrias posturais, assim como alterações na cinemática do movimento do ombro e tronco. O objetivo deste estudo foi avaliar o equilíbrio estático bem como a marcha em mulheres submetidas à cirurgia de mastectomia unilateral. Para tanto, foram analisadas 42 mulheres, divididas em dois grupos: mulheres submetidas à mastectomia unilateral (GM), com idade média de 53,77±7,24 anos, e mulheres sem a doença como controle (GC), com idade média de 54,70±6,31 anos. As análises do equilíbrio estático e da marcha foram efetuadas com sistema Vicon System (VICON-MX-T40S, Oxford, Inglaterra). Foi avaliado o equilíbrio estático com olhos abertos e olhos fechados, com e sem o uso da prótese mamária externa, por meio da área e do deslocamento do centro de massa projetado no chão, assim como o ângulo da coluna. Na marcha, foram avaliados os parâmetros espaço-temporal com e sem o uso da prótese mamária externa, e a oscilação dos membros superiores e do tronco. Foi aplicado o teste de normalidade de Shapiro-Wilk, diante de uma distribuição normal e relacionada, aplicou-se o teste T relacionado, e para amostras independentes, teste T independente, em distribuição não paramétrica, foi aplicado Wilcoxon para variáveis relacionadas e Mann-Whitney, para variáveis independentes. Foi fixado o nível crítico de 5% (p<0,05), o processamento dos dados efetuado pelo software SPSS, versão 17.0. A análise do equilíbrio estático apontou aumento significativo na área e no deslocamento do centro de massa projetado no chão, e deslocamento médio-lateral do ângulo da coluna. Na marcha, houve piora dos parâmetros espaço-temporal e menor oscilção do membro superior homolateral à cirurgia para movimentos de flexão/extensão e abdução/adução, o tronco apresentou menor oscilação médio-lateral. A prótese parece não ter influenciado no equilíbrio e na marcha. Os resultados sugerem que a mastectomia unilateral pode afetar o equilíbrio e a marcha. / Women undergoing mastectomy, have postural asymmetries as well as changes in the kinematics of the movement of the shoulder and spine. The objective of this study was to evaluate static balance and gait in women undergoing unilateral mastectomy surgery. Therefore, 42 women were analyzed, divided into two groups: women who underwent unilateral mastectomy (GM) with a mean age of 53.77 ± 7.24 years, and women without the disease as control (GC) with a mean age of 54.70 ± 6.31 years. Analyses of static equilibrium and gait was performed with Vicon System (MX-T40S-VICON, Oxford, England). We evaluated the static balance with eyes open and eyes closed, with and without the use of external breast prosthesis through the area and the center of mass displacement designed on the floor, as well as the angle of the spine. On the gait were evaluated spatiotemporal parameters with and without the use of external breast prosthesis and the oscillation of the upper limbs and trunk during walking. The functionality of the upper limbs was measured by the DASH questionnaire, and the level of physical activity by IPAQ. We used the Shapiro-Wilk normality test, before a normal and related distribution, we applied the related t test for independent samples and, independent t test, in non-parametric distribution, Wilcoxon was applied to related variables and Mann Whitney test for independent variables was set the critical level of 5% (p <0.05), the processing of data carried out by SPSS software, version 17.0. The static equilibrium analysis indicated a significant increase in the area and the center of mass offset projected on the ground and the medial-lateral displacement of the spine angle. On the march, there was worsening of spatiotemporal parameters and lower swing in arm ipsilateral to surgery for flexion/extension and abduction/adduction, trunk shows less medial-lateral oscillation. The prosthesis seems to have no influence on balance and gait. The results suggest that unilateral mastectomy can affect the balance and gait.

There are millions of fall-related injuries worldwide requiring medical attention on a yearly basis. These falls place a financial burden on the healthcare system. These falls can occur in the event of disruption in the postural control system and/or a loss of balance while walking. Previously, most gait studies have focused on the assessment of the lower extremities while neglecting the contribution of arm swing as it was believed to be a passive motion. However, it has been shown that there is an active component to arm swing. Moreover, these arm movements have been shown to affect the motion of the center of mass when walking. Therefore, arm swing could mitigate the destabilizing effects of perturbations caused by challenging surfaces. Additionally, no studies have examined the effect of arm swing when walking on a rocky surface. This type of surface causes perturbations in the anteroposterior and mediolateral directions simultaneously, leading to uneven center of mass displacement and spatiotemporal modifications. Hence, the present study assessed the effect of normal arm swing, held arm swing and active arm swing on postural control and dynamic stability when walking on regular and rocky surface. We hypothesized that active arm swing will have a negative impact on postural control and gait dynamics on a regular surface, while rocky surface walking will decrease stability and increase spatiotemporal variability. Additionally, we expect active arm swing to attenuate the negative effects of the rocky surface. Fifteen healthy young adults from the University of Ottawa community (mean age 23.4 ± 2.8 years) were recruited to participate in this study. They were asked to walk using three different arm conditions (normal, held and active arm swing) on the dual-belt CAREN-Extended System (Motek Medical, Amsterdam, NL) on simulated regular and rocky surface. This last is generated using the “Rumble” module (maximum range of ±2 cm at 0.6 Hz vertically, ±1° at 1 Hz pitch, and ±1° at 1.2 Hz roll). Mean, standard deviation and maximal values of trunk linear and angular velocity were calculated in all three planes. Moreover, step length, time and width mean and coefficient of variation as well as margin of stability mean and standard deviation were calculated. A mixed linear model was performed to compare the effects of the arm swing motions and surface types. The arm and surface conditions were set as fixed effects, while the walking speed was set as a covariate. Active arm swing increased trunk linear and angular velocity variability and peak values compared to normal and held arm conditions. Active arm swing also increased participants’ step length and step time, as well as the variability of margin of stability. Similarly, rocky surface walking increased trunk kinematics variability and peak values compared to regular surface walking. Furthermore, rocky surface increased the average step width while reducing the average step time. The spatiotemporal adaptations show the use of “cautious” gait to mitigate the destabilizing effects of both the active arm swing and rocky surface walking and, ultimately, maintain stability.

Introduction: Asymmetric gait is prevalent among older adults as well as in people with gait pathologies (e.g., Parkinson’s disease, following a stroke) and has been linked to a higher risk of falls. While a certain level of gait asymmetry is present in healthy young adults, the simulation of larger asymmetry in this population provides information about efficient strategies to regulate dynamic stability. Research investigating gait asymmetry has described spatiotemporal and kinematic strategies. However, limited information is available regarding changes in gait kinetics. Research objectives: This thesis aims to determine the gait control strategies utilized by young adults to regulate simulated gait asymmetry combined with different arm movement amplitude. We hypothesized that the hip joint would be the most affected by different arm swing conditions and asymmetric gait. We also hypothesized that asymmetric gait and active arm swing would lead to increased variability in the lower-limb movements. Methods: Fifteen healthy young adults (23.4±2.8 years, 7 Females) walked with three arm swing conditions (held, normal, and active) during symmetric and asymmetric walking conditions. The CAREN-extended System (Motek Medical, Amsterdam, NL) was used for data collection. Outcome measures included step length and width mean and variability (meanSD), vertical ground reaction forces, and lower-limb joint moment impulse mean and variability (meanSD) in the sagittal and frontal planes. Results: When comparing arm swing conditions, the active arm swing led to an increase in step width variability, vertical ground reaction forces, hip and knee variability in the sagittal plane, ankle abduction moment for the fast leg, as well as in knee variability in the frontal plane. As for gait symmetry, the asymmetric condition led to increased step width for the fast and slow legs and increased vertical ground reaction forces for the slow leg. The asymmetric condition further prompted adjustments in the frontal and sagittal planes, particularly at the ankle and hip joints during the braking phase, and in the knee joint during the propulsion phase phases when compared to the symmetric walking condition. Conclusion: Findings suggest that participants increased hip activity to control the effect of arm motion on the trunk to minimize adaptations in the lower-limb joints. The asymmetry condition demonstrated that participants searched for flexible lower-limb strategies aimed at minimizing bilateral differences between the fast and slow legs during asymmetric walking.