• Compensatory Arm Reactions in Individuals with Parkinson’s Disease

      Weaver, Tyler; Applied Health Sciences Program (Brock University, 2013-01-14)
      This study examined how perturbation-evoked compensatory arm reactions in individuals with Parkinson’s disease (PD) are influenced by explicit verbal instruction. Ten individuals with PD and 15 older adults without PD responded to surface translations with or without specific instruction to reach for and grasp the handrail. Electromyographic (EMG) and kinematic recordings were taken from the reaching arm. Results showed that individuals with and without PD benefitted similarly from explicit instruction. Explicit instruction resulted in earlier (p=0.005) and larger (p<0.001) medial deltoid EMG responses in comparison to no specific instructions. Compensatory arm reactions also occurred with a higher peak medio-lateral wrist velocity (p<0.001) and higher peak shoulder abduction angular velocity (p<0.001) with explicit instruction. Explicit instruction positively influenced compensatory arm reactions in individuals with and without PD. Future research is needed to determine whether the benefits of instruction persist over time and translate to a loss of balance in real life.
    • The Development of a Novel Pitching Assessment Tool

      Birfer, Richard; Applied Health Sciences Program
      Posture based ergonomic assessment tools are widely used to evaluate posture and injury risk for many workplace/occupational tasks. To date, there is no validated equivalent that can be used to assess the posture of a pitcher during baseball pitching. Therefore, the purpose of this study was to develop an inexpensive tool which can allow for the rapid assessment of a pitcher’s posture at lead foot strike, and establish the inter- and intra- rater reliability of the tool. For this study, 11 participants threw 30 pitches (15 fastballs, 15 curveballs) off an indoor pitching. Full body 3D kinematics were measured using reflective markers attached to anatomical landmarks and rigid bodies attached to body segments using a 10-camera Vicon Motion Capture system along with two high-speed video cameras (rear and side view) to record each pitch during the experimental trials. The kinematic data was analyzed, after which the highest velocity fastball of each of the 11 pitchers was selected for further analysis. A Pitching Mechanics Tool was designed to evaluate 16 different parameters at lead foot strike. Each of the 16 parameters had posture ranges or categories established based on scientific literature. Six evaluators with at least five years of experience working with adult pitchers completed the Pitching Mechanics Tool. Findings showed moderate to good levels of repeatability across multiple sessions as well as across multiple evaluators. Additionally, PMT results suggested that 2D qualitative analysis is a viable alternative to 3D motion capture.
    • The Effect of Blade Alignment on Kinetic and Kinematic Characteristics During the Execution of Goaltender-Specific Movement Patterns

      Dunne, Colin; Applied Health Sciences Program
      The goaltender skate traditionally consists of the boot, cowling, and blade runner. The cowling protects the foot and positions the blade on the boot. Innovations in boot design and material properties have deemed the cowling redundant, presenting the opportunity to manipulate skate blade alignment and potentially reveal a performance advantage. The purpose of the study was to investigate the effect of blade alignment on select kinetic and kinematic variables during the execution of two goaltender-specific movement patterns; Butterfly Drop to Recovery, Lateral Butterfly Slide to Recovery. A male goaltender (n = 1) with professional hockey experience completed an A-B-A, quasi-experimental design across three days investigating four blade alignment conditions. Blade alignment conditions were defined by the blade holder type and positioning on the boot [alignment neutral cowling (ANC), alignment neutral (AN), alignment lateral (AL), and alignment medial (AM)]. Five trials were executed per blade alignment condition for both movements (n=30 trials per day, n=90 trials overall). All trials were executed in a controlled laboratory environment on synthetic ice (xHockeyProductsTM). Kinetic measures included; in-skate peak plantar pressure [PPP(psi)], time to peak plantar pressure [TPP(s)] collected with in-skate LogRTM insoles (Orpyx® Medical Technologies Inc.). Kinematic measures included; butterfly drop velocity [BDV(m/s)], left leg recovery velocity [LLRV(m/s)], right leg recovery velocity [RLRV(m/s)], lateral butterfly slide velocity [LBSV(m/s)], butterfly width [BW(m)] collected with 3D motion capture (ViconTM). Results revealed no significant differences in nineteen of twenty kinetic and kinematic analyses between the two neutral alignment conditions (ANC, AN) defined by different holder types. True Hockey blade holders were retrofit with slots to facilitate the blade alignments. Results revealed significantly higher Butterfly Drop PPP on the AM compared to AN, and higher Left and Right Leg Recovery PPP on AM compared to AL and AN during the Butterfly Drop to Recovery. Results also revealed significantly higher BDV on AM compared to AL and AN during the Butterfly Drop to Recovery, and higher BDV on AM compared to AN during the Lateral Butterfly Slide to Recovery. Study outcomes provide insight into the contribution of manipulating blade alignment to positively impact the execution of goaltender-specific movement patterns.
    • Kinematics and Muscle Activity of the Upper Extremity While Performing Cleaning Tasks

      Pipher, Zachary; Applied Health Sciences Program
      In Canada, occupations including janitors, caretakers, and building superintendents are the fourth most prevalent occupational group among men in the labour force, while cleaners are the 10th most prevalent occupational group among women (Statistics Canada, 2008). Cleaning tasks, typically labor-intensive, are characterized by a combination of static muscle loads (mainly involving bending and twisting of the back) and repetitive movements of the arms and hands requiring high physical exertion. Tasks such as lifting, mopping, and vacuuming often involve awkward postures with both dynamic and static muscular activities. These types of prolonged static and repetitive muscle activities cause muscle fatigue and may lead to musculoskeletal disorders. Therefore, the purpose of this study was to examine the effects of custodial cleaning tasks on upper extremity muscle activity and to assess changes in kinematics throughout the duration of a shift. Ten custodians employed at Brock University performed six cleaning tasks during two different sessions (pre-shift and post-shift). Kinematics of the upper extremity were collected, and muscle activity was recorded from 8 upper extremity muscles. Our results showed no significant changes in mean joint angles or joint range of motion pre-shift to post-shift. However, significant changes were observed in mean and peak EMG amplitudes as a result of time. Higher muscle activity was observed in the upper trapezius and FDS while lower muscle activity was found in the anterior deltoid, posterior deltoid, and EDC post-shift compared to pre-shift. This suggests that custodians use different muscular strategies to maintain task performance over the duration of a work shift. This may imply they are experiencing fatigue due to insufficient rest. This work acts as a stepping-stone into future investigations of custodial work and the adaptations over time.