Centre of mass kinematics of the hammer and thrower during different hammer-throwing drills utilised for training.

During elite-level hammer throws, the vertical displacement of the centre of mass (COM) of the thrower and hammer are approximately 180° out of phase (the hammer's COM is at its high point when the thrower's COM is at its low point, and vice versa) prior to the hammer's release. This out-of-phase coordination pattern contributes to the velocity of the hammer, which ultimately contributes to the distance thrown. Several drills are used to improve coordination between the thrower's and hammer's COM, but it is not currently known if the out-of-phase pattern is present during these drills. This study examined the relative phase between the COM of the hammer and thrower during two different rotational drills: The Double Hammer Head and Single Arm drills. Using a 12-camera motion analysis system, COM kinematics for both the hammer and thrower were examined for seven NCAA Division I throwers during the two drills. Contrary to their purported purpose, the phase angles between thrower's and hammer's COM were significantly different from 180° during both drills. Further research should be conducted to examine the mechanical factors of hammer throwing drills, as well as the effect such drills have when implemented within training programs.

Aquatic treadmill walking at three depths of water in people with traumatic brain injury.

OBJECTIVE: The purpose of this study was to analyse kinematic and spatiotemporal gait characteristics of aquatic treadmill walking among three different depths of water in individuals with traumatic brain injury. METHODS: A total of 13 individuals with traumatic brain injury participated in the study and completed walking trials at three different depths as follows: waist, chest, and neck level, which was adjusted by a movable floor pool. A self-selected comfortable walking speed at the waist level was used as a matched speed for all walking trials. Participants completed three aquatic treadmill walking trials under each of the three water depths. Each participant's gait was captured by a customized underwater motion analysis system and processed by a two-dimensional motion analysis software. RESULTS: The repeated measures analysis of variance showed significant differences in spatiotemporal and joint kinematic variables across three conditions: stance swing ratio (p = .023), peak hip flexion (p = .001), hip range of motion (p = .047), and peak ankle dorsiflexion (p = .000). Various water properties in conjunction with motor impairments might have contributed to alterations in gait kinematics. CONCLUSION: Our findings suggest that walking in neck-depth water may not be ideal for gait training as it appears to limit hip flexion and ankle dorsiflexion. It is recommended that waist to chest-depth water be used to provide an accommodating environment for aquatic gait rehabilitation.

The biomechanical investigation of the relationship between balance and muscular strength in people with chronic stroke: a pilot cross-sectional study.

BACKGROUND: Impaired balance and weak muscle strength are common deficits associated with stroke. Limited research has examined the relationship between balance and strength in people post-stroke. OBJECTIVE: To investigate the association between balance and muscular strength in people post-stroke. METHODS: A total of 11 people with chronic stroke, who were community dwelling and ambulatory, completed balance and strength assessments. A computerized dynamic posturography system was used for Limits of Stability (LOS) test, Sit-to-Stand (STS) test, and the Modified Clinical Test of Sensory Interaction on Balance (mCTSIB). Additionally, a computerized dynamometer was used to assess the isometric muscle strength of flexion/extension in the core (the trunk) and the leg (the hip, knee, and ankle). Pearson correlation analysis was used to investigate the relationship between balance and muscle strength measurements. RESULTS: Endpoint excursion (EPE) (r = .646; p < 0.032) and maximum excursion (MXE) (r = .613; p < 0.045) of LOS test were positively correlated with core and leg strength (C&L). Specifically, both EPE (r = -.792; p < 0.004) and MXE (r = -.623; p < 0.041) in backward direction had strong correlations with C&L. Core strength also showed a positive correlation with EPE of LOS test (r = .636; p < 0.035) while the composite leg strength did not. Lastly, STS and mCTSIB tests did not demonstrate significant associations with muscle strength. CONCLUSIONS: The results indicate that the C&L have a strong relationship with the ability to shift body weight in multiple directions, particularly backward, among people post-stroke. However, static balance and STS performance do not appear to be related to muscle strength.

The influence of water depth on kinematic and spatiotemporal gait parameters during aquatic treadmill walking.

The purpose of this study was to investigate kinematic and spatiotemporal variables of aquatic treadmill walking at three different water depths. A total of 15 healthy individuals completed three two-minute walking trials at three different water depths. The aquatic treadmill walking was conducted at waist-depth, chest-depth and neck-depth, while a customised 3-D underwater motion analysis system captured their walking. Each participant's self-selected walking speed at the waist level was used as a reference speed, which was applied to the remaining two test conditions. A repeated measures ANOVA showed statistically significant differences among the three walking conditions in stride length, cadence, peak hip extension, hip range of motion (ROM), peak ankle plantar flexion and ankle ROM (All p values < 0.05). The participants walked with increased stride length and decreased cadence during neck level as compared to waist and chest level. They also showed increased ankle ROM and decreased hip ROM as the water depth rose from waist and chest to the neck level. However, our study found no significant difference between waist and chest level water in all variables. Hydrodynamics, such as buoyancy and drag force, in response to changes in water depths, can affect gait patterns during aquatic treadmill walking.

Cardiorespiratory Responses to Pool Floor Walking in People Poststroke.

OBJECTIVE: To compare cardiorespiratory responses between pool floor walking and overground walking (OW) in people poststroke. DESIGN: Cross-sectional study. SETTING: University-based therapeutic exercise facility. PARTICIPANTS: Participants (N=28) were comprised of 14 community-dwelling individuals poststroke (5.57±3.57y poststroke) and 14 age- and sex-matched healthy adults (mean age, 58.00±15.51y; male/female ratio, 9:5). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: A telemetric metabolic system was used to collect cardiorespiratory variables, including oxygen consumption (V˙o2), energy expenditure (EE), and expired volume per unit time (V˙e), during 6-minute walking sessions in chest-depth water and on land at a matched speed, determined by average of maximum walking speed in water. RESULTS: Individuals poststroke elicited no significant differences in cardiorespiratory responses between pool floor walking and OW. However, healthy controls showed significant increases in mean V˙o2 values by 94%, EE values by 109%, and V˙e values by 94% (all P<.05) during pool floor walking compared with OW. A 2×2 mixed model analysis of variance revealed a significant group × condition interaction in V˙o2, in which the control group increased V˙o2 from OW to pool floor walking, whereas the stroke group did not. CONCLUSIONS: Our results indicate that people poststroke, unlike healthy adults, do not increase EE while walking in water compared with on land. Unlike stationary walking on an aquatic treadmill, forward locomotion during pool floor walking at faster speeds may have increased drag force, which requires greater EE from healthy adults. Without demanding excessive EE, walking in water may offer a naturally supportive environment for gait training in the early stages of rehabilitation.

Effects of Taekwondo intervention on balance in children with autism spectrum disorder.

The purpose of this study was to investigate the effects of an 8-week Taekwondo (TKD) intervention on balance in children with autism spec-trum disorder (ASD). A total of 14 children with ASD participated in this study. Eight children (eight males; mean age, 10.25±2.38 yr) completed TKD intervention (50 min/2 times/8 week), and six children received no intervention serving as controls (five males, one female; mean age, 10.00±2.83 yr). A computed posturography system with a long forceplate (NeuroCom Balance Master) was used to evaluate static (double and single leg stance with various test conditions) and functional balance (step-quick-turn). Balance was measured before and after the intervention. A mixed-model analysis of variance showed a significant group by time interaction in single leg stance balance. After the intervention, the TKD group displayed a greater improvement in single leg stance balance with eyes closed condition than the control group (P=0.046). Within-group analysis showed that the TKD group significantly improved single leg stance balance with eyes open condition (P=0.014). In addition, TKD group displayed trends of improvements in double leg stance balance with unstable surface under eyes closed condition (ES=0.83) and step-quick-turn (Cohen d [ES]=0.70). The control group did not show any significant changes in balance outcomes. In conclusion, TKD training can help children with ASD improve their balance. Children with ASD also showed a high rate of adherence (92%) to the TKD training. Our findings suggest that TKD can be a fun, feasible, and effective therapeutic option for balance improvement of children with ASD.

The Use of Cuff Weights for Aquatic Gait Training in People Post-Stroke with Hemiparesis.

BACKGROUND AND PURPOSE: This study aimed to examine how spatiotemporal and kinematic gait variables are influenced by the application of a cuff weight during aquatic walking in people post-stroke. The secondary purpose was to compare the differences in gait responses between the placements of cuff weights on the proximal (knee weight) and distal end (ankle weight) of the shank. METHODS: Twenty-one participants post-stroke with hemiparesis aged 66.3 ± 11.3 years participated in a cross-sectional comparative study. Participants completed two aquatic walking trials at their self-selected maximum walking speed across an 8-m walkway under each of the three conditions: 1) walking with a knee weight; 2) walking with an ankle weight; and 3) walking with no weight. Cuff weights were worn on the paretic leg of each participant. Gait speed, cadence, step width and joint kinematics of the hip, knee and ankle joints were recorded by a customized three-dimensional underwater motion analysis system. RESULTS: Mean aquatic walking speeds significantly increased with the use of cuff weights when compared to walking with no weight. Changes in gait variables were found in the non-paretic leg with the addition of weight, while no significant changes were found in the paretic leg. CONCLUSION: The results suggest that the use of additional weight can be helpful if the goal of gait training is to improve walking speed of people post-stroke during pool floor walking. However, it is interesting to note that changes in gait variables were not found in the paretic limb where favourable responses were expected to occur.

Post-exercise hypotensive responses following an acute bout of aquatic and overground treadmill walking in people post-stroke: a pilot study.

BACKGROUND: The purpose of this study is to investigate the effects of a single-bout of aquatic treadmill walking (ATW) and overground treadmill walking (OTW) on the magnitude and duration of post-exercise ambulatory blood pressure (BP) in people post-stroke. METHODS: Seven people post-stroke participated in a cross-sectional comparative study. BP was monitored for up to 9 hours after a 15-minute bout of ATW and OTW at approximately 70% of maximal oxygen consumption (VO2max), performed on separate days. Mean systolic and diastolic BP values were compared between both exercise conditions and a day without exercise (control). RESULTS: Three hours after OTW, mean SBP increased by 9% from pre-exercise baseline compared to a 3% decrease during the control day (P < 0.05). A similar trend was observed after the third hour of ATW (P = 0.06). However, ATW demonstrated a 3% overall decline in DBP after exercise compared to a 1% DBP increase of the control day (P < 0.05). Additionally, ATW showed a 6% reduction in mean systolic BP at the ninth hour post-exercise (P < 0.05) compared to baseline. CONCLUSION: Our results indicate people post-stroke can sustain sufficient walking intensities necessary to reduce BP following cardiovascular exercise. Also, these data suggest that ATW can elicit clinically meaningful reductions in DBP and night-time SBP. Thus, it is recommended for clinicians to consider ATW as a non-pharmaceutical means to regulate DBP and promote nighttime dipping of SBP in people post-stroke. However, caution is advised during the immediate hours after exercise, a period of possible BP inflation.

Comparison of energy expenditure between aquatic and overground treadmill walking in people post-stroke.

BACKGROUND AND PURPOSE: This study aimed to compare the cardiorespiratory responses between aquatic treadmill walking (ATW) and overground treadmill walking (OTW) in people with hemiparesis post-stroke. METHODS: Eight participants post-stroke aged 58.5 ± 11.4 years and eight healthy adult controls aged 56.1 ± 8.6 years participated in a cross-sectional comparative study. Participants completed three 8-minute walking sessions separated by at least 72-hour rest. On the first visit, participants identified their comfortable walking speed on an aquatic and overground treadmill. The second and third visit consisted of either ATW or OTW at a matched speed. Oxygen consumption (VO2), carbon dioxide production (VCO2 ), minute ventilation (VE) and energy expenditure (EE) were measured at rest and during walking in both exercise modes. RESULTS: Mean steady-state cardiorespiratory responses during ATW showed a significant decrease compared with OTW at a matched speed. During ATW, mean VO2 values decreased by 39% in the stroke group and 21% in the control group, mean VCO2 values decreased by 42% in the stroke group and 30% in the control group, and mean EE decreased by 40% in the stroke group and 25% in the control group. Mean steady-state VE values and resting cardiorespiratory response values showed no significant change between the two conditions. CONCLUSION: This study demonstrated a decreased metabolic cost when ATW at matched speeds to that of OTW. Reduced metabolic cost during ATW may allow for longer durations of treadmill-induced gait training compared with OTW for improved outcomes. This knowledge may aid clinicians when prescribing aquatic treadmill exercise for people post-stroke with goals of improving gait and functional mobility. However, decreased metabolic cost during ATW suggests that to improve cardiovascular fitness, ATW may not be a time-efficient method of cardiovascular exercise for healthy adults and people post-stroke.

The influence of applying additional weight to the affected leg on gait patterns during aquatic treadmill walking in people poststroke.

UNLABELLED: Jung T, Lee D, Charalambous C, Vrongistinos K. The influence of applying additional weight to the affected leg on gait patterns during aquatic treadmill walking in people poststroke. OBJECTIVE: To investigate how the application of additional weights to the affected leg influences gait patterns of people poststroke during aquatic treadmill walking. DESIGN: Comparative gait analysis. SETTING: University-based aquatic therapy center. PARTICIPANTS: Community-dwelling volunteers (n=22) with chronic hemiparesis caused by stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Spatiotemporal and kinematic gait parameters. RESULTS: The use of an ankle weight showed an increase in the stance phase percentage of gait cycle (3%, P=.015) when compared with no weight. However, the difference was not significant after a Bonferroni adjustment was applied for a more stringent statistical analysis. No significant differences were found in cadence and stride length. The use of an ankle weight showed a significant decrease of the peak hip flexion (7.9%, P=.001) of the affected limb as compared with no weight condition. This decrease was marked as the reduction of unwanted limb flotation because people poststroke typically show excessive hip flexion of the paretic leg in the late swing phase followed by fluctuating hip movements during aquatic treadmill walking. The frontal and transverse plane hip motions did not show any significant differences but displayed a trend of a decrease in the peak hip abduction during the swing phase with additional weights. The use of additional weight did not alter sagittal plane kinematics of the knee and ankle joints. CONCLUSIONS: The use of applied weight on the affected limb can reduce unwanted limb flotation on the paretic side during aquatic treadmill walking. It can also assist the stance stability by increasing the stance phase percentage closer to 60% of gait cycle. Both findings can contribute to the development of more efficient motor patterns in gait training for people poststroke. The use of a cuff weight does not seem to reduce the limb circumduction during aquatic treadmill walking.

The relationship between consistency of propulsive cycles and maximum angular velocity during wheelchair racing.

The purposes of this study were to examine the consistency of wheelchair athletes' upper-limb kinematics in consecutive propulsive cycles and to investigate the relationship between the maximum angular velocities of the upper arm and forearm and the consistency of the upper-limb kinematical pattern. Eleven elite international wheelchair racers propelled their own chairs on a roller while performing maximum speeds during wheelchair propulsion. A Qualisys motion analysis system was used to film the wheelchair propulsive cycles. Six reflective markers placed on the right shoulder, elbow, wrist joints, metacarpal, wheel axis, and wheel were automatically digitized. The deviations in cycle time, upper-arm and forearm angles, and angular velocities among these propulsive cycles were analyzed. The results demonstrated that in the consecutive cycles of wheelchair propulsion the increased maximum angular velocity may lead to increased variability in the upper-limb angular kinematics. It is speculated that this increased variability may be important for the distribution of load on different upper-extremity muscles to avoid the fatigue during wheelchair racing.