Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking

AimCentral arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT.MethodsGait speed was measured using a motion capture system in 56 women (30–80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7′s. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery.ResultsThe percent change in gait speed was larger for MT than DT (14.1 ± 11.2 vs. 8.7 ± 9.6%, p < 0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85 ± 0.43 vs. 1.47 ± 0.42, p = 0.02) and resistance (0.75 ± 0.07 vs. 0.68 ± 0.07, p = 0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences.ConclusionElevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.     

Sleep quality is associated with walking under dual-task,but not single-task performance

ObjectivesThe objective of this study was to assess the relationship between sleep behavior and gait performance under single-task (ST) and dual-task (DT) walking conditions in community- dwelling older adults.MethodsWalking under ST and DT conditions was evaluated in 34 community-dwelling older adults, 64.7% women, mean age 71.5 (SD ± 5.8). Gait-speed and gait-variability data were collected using the OPAL wearable sensors of the Mobility Lab. Sleep behavior (sleep efficiency [SE] and sleep latency [SL]) was assessed using actigraphy, over 5 consecutive nights.ResultsLower SE was associated with decreased gait speed and increased stride-length variability during DT (rs = 0.35; p = 0.04; rs = −0.36; p = 0.03, respectively), whereas longer SL was associated with increased stride-length variability during DT (rs = 0.38; p = .03). After controlling for age and cognition, SE accounted for 24% and 33% of the variability in stride length and stride time. No associations were found between sleep and gait measures under ST walking.ConclusionsLower SE is associated with decreased gait speed and increased gait variability under DT conditions that are indicative of an increased risk for falls in older adults. Our findings support clinical recommendations to incorporate the evaluation of sleep quality in the context of risk assessment for falls.     

Cognitive-motor interference in multiple sclerosis: What happens when the gait speed is fixed?

During the last decade, numerous studies have confirmed a coupling between walking performance and cognition in people with multiple sclerosis (PwMS). Our aim was to provide new insights into a walking-cognitive dual-task (DT) in PwMS. We tested the DT phenomenon by controlling the walking speed using an instrumented treadmill. Thirty PwMS (20 women) with a mean age 40.1 (SD = 12.0) participated in the study. Twenty-one healthy subjects served as controls. Each subject completed a sequence of tests: a) Normal walking (ST) − the participant walked on the instrumented treadmill at a comfortable walking speed for 1 min; b) Cognitive evaluation (ST) − subjects performed two cognitive tests while seated; c) DT cognitive tests performed while walking on the treadmill at the identical speed performed during normal walking. Outcome measures were spatio-temporal parameters of gait (mean and variability), the Word List Generation Test (WLG) and the Serial-3 Subtraction Test. MS participants significantly decreased their cadence while increasing their stride length during the DT condition compared to the ST condition. Non-significant differences were observed for the WLG and Serial-3 Subtraction Cognitive Tests between the ST condition and the DT condition in both the MS and healthy groups. In terms of gait variability parameters, MS subjects demonstrated a 2 to 3-fold greater gait variability compared to the healthy controls. Non-significant differences in gait variability parameters were observed between the ST and DT conditions in both the MS and control groups. This study provides new insights into the DT phenomenon in the MS population.     

Tandem gait test performance in healthy,physically active adults: Clinical implications for concussion evaluation

ObjectivesTo identify factors affecting performance on the tandem gait test in healthy, physically active adults.DesignCross-sectional.MethodsParticipants completed the tandem gait test according to Sport Concussion Assessment Tool 3 (SCAT3) guidelines. Dependent variables included time for best trial (initial 3 m, turn, final 3 m and total) and whether the trial was “pass” or “fail”. Independent variables included sex, concussion history, foot length, height and total number of trials.Results55% (35/64) of participants passed the first trial of the tandem gait test; 19% (12/64) had a best time <14 s. Sex and concussion history did not affect performance (p > 0.05). There were no differences in turn times for those with and without a history of concussion (t = 0.26, p = 0.80). The number of trials was not significantly correlated with best time (þ = ?0.04, p = 0.74). There were low (þ = ?0.31) to negligible (þ < 0.30) correlations between foot length, height and all portions of the test. There was more variability in times for the turn (COV = 27%) than during the straight portions (COV = 18%).ConclusionsCurrent recommendations for the tandem gait test led to a high false-positive rate in healthy, physically active adults. Sex, concussion history, number of trials and foot length had little to no influence on scores on the test. Turning times were more variable than times on the straight portions of the test. Clinicians may use these results as a guideline when interpreting performance on the tandem gait test in healthy physically active adults.     

Different cognitive functions discriminate gait performance in younger and older women: A pilot study

AimCognitive dysfunction is associated with slower gait speed in older women, but whether cognitive function affects gait performance earlier in life has yet to be investigated. Thus, the objective of this study was to test the hypothesis that cognitive function will discriminate gait performance in healthy younger women.MethodsFast-pace and dual-task gait speed were measured in 30 young to middle-aged (30–45 y) and 26 older (61–80 y) women without mild cognitive impairment. Visuoperceptual ability, working memory, executive function, and learning ability were assessed using neuropsychological tests. Within each age group, women were divided by the median into lower and higher cognitive function groups to compare gait performance.ResultsYounger women with higher visuoperceptual ability had faster fast-pace (2.25 ± 0.30 vs. 1.98 ± 0.18 m/s, p ≤ 0.01) and dual-task gait speed (2.02 ± 0.27 vs. 1.69 ± 0.25 m/s, p ≤ 0.01) than women with lower visuoperceptual ability. The difference in dual-task gait speed remained significant (p = 0.02) after adjusting for age, years of education, and other covariates. Dividing younger women based on other cognitive domains showed no difference in gait performance. In contrast, working memory and executive function discriminated dual-task gait speed (p < 0.05) in older women after adjusting for age and education.ConclusionTo our knowledge, this is the first study to show that poorer cognitive function even at a relatively young age can negatively impact mobility. Different cognitive functions discriminated gait performance based on age, highlighting a possible influence of aging in the relationship between cognitive function and mobility in women.     

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age = 15.0 ± 2.1 years, 7.5 ± 3.0 days post-injury) and 51 controls (51% female, mean age = 14.4 ± 2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0 ± 18.0) and males (27.8 ± 18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (−19.7% ± 10.0% vs. −11.3% ± 9.2%, p = 0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13 ± 0.11 m vs. 1.26 ± 0.11 m, p = 0.001; males: 1.14 ± 0.14 m vs. 1.22 ± 0.15 m, p = 0.04) and dual-task gait (females: 0.99 ± 0.10 m vs. 1.10 ± 0.11 m, p = 0.001; males: 1.00 ± 0.13 m vs. 1.08 ± 0.14 m, p = 0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.     

Cardiovascular responses to heat acclimatisation in athletes with spinal cord injury

ObjectivesTo determine the effect of heat acclimatisation (HA) training on blood profile and resting cardiac function in elite athletes with spinal cord injury (SCI).DesignQuasi-experimental.MethodsEleven athletes (10 m, 1f) with SCI (C5-T3) completed a five-day isothermic HA protocol whereby gastrointestinal temperature (Tc) was elevated to and maintained at ∼38.5 degrees Celsius (°C) via intermittent exercise for sixty minutes each day. Blood samples were collected pre- and post-HA to determine changes in plasma volume (PV). Doppler ultrasound of the left-ventricular outflow tract and 2-d speckle tracking echocardiography were performed in a subset of athletes (n = 5) to determine changes in indices of resting left-ventricular function and mechanics, respectively.ResultsTen athletes were successfully able to raise and maintain Tc to 38.5 °C. There was a non-significant increase in PV with HA training (ΔPV%: 3.0 ± 5.4%, p = 0.086). Following HA, resting HR decreased (63 ± 4 pre-HA vs. 58 ± 5 bpm post-HA, p = 0.020), velocity time integral (21.4 ± 2.7 vs. 23.7 ± 3.0 cm, p = 0.045) and stroke volume increased (64.8 ± 7.6 vs. 70.2 ± 10.5 mL, p = 0.055).ConclusionsOur findings suggest a short-term HA protocol in athletes with SCI is safe and may induce beneficial changes in indices of resting left-ventricular function — however results are highly individualized. Future studies on HA in athletes with SCI should focus on determining mechanisms of adaptation and performance outcomes.     

Gait Profile Score in multiple sclerosis patients with low disability

BackgroundGait abnormalities are subtle in multiple sclerosis (MS) patients with low disability and need to be better determined. As a biomechanical approach, the Gait Profile Score (GPS) is used to assess gait quality by combining nine gait kinematic variables in one single value. This study aims i) to establish if the GPS can detect gait impairments and ii) to compare GPS with discrete spatiotemporal and kinematic parameters in low-disabled MS patients.MethodThirty-four relapsing-remitting MS patients with an Expanded Disability Status Scale (EDSS) score ≤2 (mean age 36.32 ± 8.72 years; 12 men, 22 women; mean EDSS 1.19 ± 0.8) and twenty-two healthy controls (mean age 36.85 ± 7.87 years; 6 men, 16 women) matched for age, weight, height, body mass index and gender underwent an instrumented gait analysis.ResultsNo significant difference in GPS values and in spatiotemporal parameters was found between patients and controls. However patients showed a significant alteration at the ankle and pelvis level.ConclusionGPS fails to identify gait abnormalities in low-disabled MS patients, although kinematic analysis revealed subtle gait alterations. Future studies should investigate other methods to assess gait impairments with a gait score in low-disabled MS patients.     

Is there an athlete’s artery? A comparison of brachial and femoral artery structure and function in male strength,power and endurance athletes

ObjectivesExercise places physiological demands upon the cardiovascular system, subsequently leading to adaptations in structure and function. Different exercise modalities (endurance, strength and power) lead to distinct hemodynamic demands and, possibly, different patterns of adaptation. Our aim was to assess and compare brachial and femoral artery function and structure in elite level athletes engaged in endurance, strength and power sports.Designcross sectional comparison.Methods30 male elite athletes (runners n = 10, powerlifters n = 11, weightlifters n = 9) and 23 healthy controls were recruited. Brachial and femoral arterial diameters were assessed using ultrasound. Arterial function (brachial and femoral arteries) was determined using the flow mediated dilation (FMD) technique and body composition using body mass index (BMI) and body surface area (BSA).ResultsWeightlifters had significantly larger brachial arterial diameters compared to controls (4.39 ± 0.34 vs 3.86 ± 0.42 mm, p < 0.01). As weightlifter and power athletes had significantly higher body mass, BMI and BSA, we adjusted diameter for BSA. BSA-correction ameliorated differences in brachial artery resting diameters between athletes and controls. However, BSA-corrected femoral artery diameter was significantly larger in runners compared to controls (3.51 ± 0.28 vs 3.25 ± 0.34 mm, p < 0.05). There were no differences in brachial FMD between groups. Femoral artery FMD was significantly higher in runners and weightlifters compared to controls (p < 0.05 for both groups).ConclusionsHeterogeneous, limb-specific structural and functional vascular adaptation is evident in athletes, which may be influenced by exercise modality. Further, vascular remodelling relates to differences in body shape, specifically body composition, which should be accounted for when comparing athletes.     

A comparison of two walking while talking paradigms in aging

BackgroundOur study aimed to [1] compare dual-task costs in gait and cognitive performance during two dual-task paradigms: walking while reciting alternate letters of the alphabet (WWR) and walking while counting backward by sevens (WWC); [2] examine the relationship between the gait and cognitive interference tasks when performed concurrently.ScopeGait and cognitive performance were tested in 217 non-demented older adults (mean age 76 ± 8.8 years; 56.2% female) under single and dual-task conditions. Velocity (cm/s) was obtained using an instrumented walkway. Cognitive performance was assessed using accuracy ratio: [correct responses]/[total responses]. Linear mixed effects models revealed significant dual-task costs, with slower velocity (p < .01) and decreased accuracy ratio (p < .01) in WWR and WWC compared to their respective single task conditions. Greater dual-task costs in velocity (p < .01) were observed in WWC compared to WWR. Pearson correlations revealed significant and positive relationships between gait and cognitive performance in WWR and WWC (p < .01); increased accuracy ratio was associated with faster velocity.ConclusionsOur findings suggested that dual-task costs in gait increase as the complexity of the cognitive task increases. Furthermore, the positive association between the gait and cognitive tasks suggest that dual-task performance was not influenced by task prioritization strategies in this sample.     

Functional balance assessment in recreational college-aged individuals with a concussion history

Objectives

Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.

Unplanned gait termination in individuals with multiple sclerosis

Despite the pervasive nature of gait impairment in multiple sclerosis (MS), there is limited information concerning the control of gait termination in individuals with MS. The purpose of this investigation was to examine unplanned gait termination with and without cognitive distractors in individuals with MS compared to healthy controls. Thirty-one individuals with MS and 14 healthy controls completed a series of unplanned gait termination tasks over a pressure sensitive walkway under distracting and non-distracting conditions. Individuals with MS were further broken down into groups based on assistive device use: (no assistive device (MS_noAD) n = 18; and assistive device (MS_AD) n = 13). Individuals with MS who walked with an assistive device (MS_AD: 67.8 ± 15.1 cm/s) walked slower than individuals without an assistive device (MS_noAD: 110.4 ± 32.3 cm/s, p < 0.01) and controls (120.0 ± 30.0 cm/s; p < 0.01). There was a significant reduction in velocity in the cognitively distracting condition (93.4 ± 32.1 cm/s) compared to the normal condition [108.8 ± 36.2 cm/s; F(1,43) = 3.4, p = 0.04]. All participants took longer to stop during the distracting condition (1.7±0.6 s) than the non-distracting condition (1.4 ± 0.4 s; U = 673.0 p < 0.01). After controlling for gait velocity, post-hoc analysis revealed the MS_AD group took significantly longer to stop compared to the control group (p = 0.05). Further research investigating the control of unplanned gait termination in MS is warranted.     

The use of the dual-task paradigm in detecting gait performance deficits following a sports-related concussion: A systematic review and meta-analysis

ObjectivesThe purpose of this systematic review was to determine the viability of the dual-task paradigm in the evaluation of a sports-related concussion.DesignSystematic review and meta-analysis.MethodsEight electronic databases were searched from their inception until the 11^th of April 2011. Studies were grouped according to their reported gait performance variables and their time(s) of assessment(s). Raw mean differences (MD) and 95% confidence intervals (CI) were calculated based on raw means and standard deviations for gait performance measures in both single- and dual-task conditions. Dual-task deficits were pooled using a random effects model and heterogeneity (I²) between studies was assessed.ResultsTen studies representing a total sample of 168 concussed and 167 matched (age and gender) non-concussed participants met the inclusion criteria. Meta-analysis demonstrated that dual-task performance deficits were detected (p < 0.05) in the concussed group for gait velocity (GV) (MD = ?0.133; 95% CI ?0.197, ?0.069) and range of motion of the centre of mass in the coronal plane (ML-ROM) (MD = 0.007; 95% CI 0.002, 0.011), but not in the non-concussed group; GV (MD = ?0.048; 95% CI ?0.101, 0.006), ML-ROM (MD = 0.002; 95% CI ?0.001, 0.005).ConclusionsThe results of this study indicate that GV and ML-ROM are sensitive measures of dual-task related changes in concussed patients and should be considered as part of a comprehensive assessment for a sports-related concussion.     

Cognitive motor interference during dual-task gait in essential tremor

BackgroundFunctional ambulation requires concurrent performance of motor and cognitive tasks, which may create interference (degraded performance) in either or both tasks. People with essential tremor (ET) demonstrate impairments in gait and cognitive function. In this study we examined the extent of interference between gait and cognition in people with ET and controls during dual-task gait.MethodsWe tested 62 controls and 151 ET participants (age range: 72–102). ET participants were divided into two groups based on median score on the modified Mini Mental State Examination. Participants walked at their preferred speed, and performed a verbal fluency task while walking. We analyzed gait velocity, cadence, stride length, double support time, stride time, step width, step time difference, coefficient of variation (CV) of stride time and stride length.ResultsVerbal fluency performance during gait was similar across groups (p = 0.68). Velocity, cadence and stride length were lowest whereas step time difference (p = 0.003), double support time (p = 0.009), stride time (p = 0.002) and stride time CV (p = 0.007) were highest for ET participants with lower cognitive scores (ETp-LCS), compared with ET participants with higher cognitive scores (ETp-HCS) and controls. ETp-LCS demonstrated greatest interference for double support time (p = 0.005), step time difference (p = 0.013) and stride time coefficient of variation (p = 0.03).ConclusionsETp-LCS demonstrated high levels of cognitive motor interference. Gait impairments during complex tasks may increase risk for falls for this subgroup and underscore the importance of clinical assessment of gait under simple and dual-task conditions.     

Prevalence of urinary incontinence among elite athletes of both sexes

ObjectivesTo determine the prevalence of urinary incontinence (UI) among elite athletes and to compare prevalences between sexes and across different sports modalities.MethodsThis was a cross-sectional, observational study conducted in 754 elite athletes (455 women or girls and 299 men or boys). Participants completed a questionnaire to collect self-reported anthropometric measures, medical history and sport-related data, and the questionnaires International Consultation on Incontinence Questionnaire-UI Short-Form (ICQ-UI SF), Three Incontinence Questions (3IQ) and Incontinence Severity Index (ISI).ResultsAccording to replies to the ICQ-UI SF questionnaire, 33% of the athletes had UI at a mean age of 23.75 ± 7.74 years. Prevalences were 45.1% in female compared to 14.7% male athletes (p < 0.001) such that females were 5.45 times more likely to suffer this condition. In 59.9%, incontinence was stress UI. In 30.9%, UI was described as moderate to severe (according to ISI), and quality of life related to UI was scored 4.35 ± 2.98 out of 10 (ICQ-UI SF). 22.7% reported they had experienced urine leakage while training; in 40.5% this occurred when jumping, in 19.6% while running and in 20.2% in different situations.ConclusionsThe prevalence of UI observed in elite athletes was 33%. This prevalence was greater in females and also varied according to the sport practised.     

Prevalence and application of priming exercise in high performance sport

ObjectivesRecent research has revealed that low volume resistance ‘priming’ exercise may improve neuromuscular performance when completed within 48 h before competition. The aim of this study was to investigate the current prevalence and application of this strategy by practitioners in sport.DesignThis study surveyed practitioners who were currently programming and/or prescribing resistance training programs for high performance athletes.MethodsSixty-nine practitioners completed the online survey relating to their perceptions of resistance priming exercise strategies and the training methods prescribed in the days prior to competition.ResultsFifty-one percent of respondents currently prescribed priming exercise. Of the practitioners who prescribed this strategy, most respondents (59%) prescribed this session within 8 h of competition. Sessions typically included 2–3 upper body and lower body exercises (mean = 2.5 ± 0.7 and 2.1 ± 0.6 respectively), usually involving both loaded and unloaded activities. Large variations in exercise selection were reported, however, unloaded jumps (87%), loaded jumps (60%) and bench press (56%) were commonly prescribed. A low volume of sets (mean = 2.8 ± 0.9) and repetitions (mean = 3.8 ± 1.3) were used during these sessions. Lastly, various resistance loading strategies were prescribed, ranging from unloaded activities to heavy loaded exercises performed at ≥85% 1RM.ConclusionsPriming exercise is currently prescribed by many practitioners to prepare athletes for competition. A wide range of priming exercise methods are used, despite limited evidence supporting these methods. Future research should examine the effects of the various priming methods which are currently applied in practice.     

Normative EMG patterns of ankle muscle co-contractions in school-age children during gait

PurposeThe study was designed to assess the co-contractions of tibialis anterior (TA) and gastrocnemius lateralis (GL) in healthy school-age children during gait at self-selected speed and cadence, in terms of variability of onset-offset muscular activation and occurrence frequency.MethodsStatistical gait analysis, a recent methodology performing a statistical characterization of gait by averaging spatio-temporal and sEMG-based parameters over numerous strides, was performed in 100 healthy children, aged 6-11 years. Co-contractions were assessed as the period of overlap between activation intervals of TA and GL.ResultsOn average, 165 ± 27 strides were analyzed for each child, resulting in approximately 16,500 strides. Results showed that GL and TA act as pure agonist/antagonists for ankle plantar/dorsiflexion (no co-contractions) in only 19.2 ± 10.4% of strides. In the remaining strides, statistically significant (p < 0.05) co-contractions appear in early stance (46.5 ± 23.0% of the strides), mid-stance (28.8 ± 15.9%), pre-swing (15.2 ± 9.2%), and swing (73.2 ± 22.6%). This significantly increased complexity in muscle recruitment strategy beyond the activation as pure ankle plantar/dorsiflexors, suggests that in healthy children co-contractions are likely functional to further physiological tasks as balance improvement and control of joint stability.ConclusionsThis study represents the first attempt for the development in healthy children of a normative dataset for GL/TA co-contractions during gait, achieved on an exceptionally large number of strides in every child and in total. The present reference frame could be useful for discriminating physiological and pathological behavior in children and for designing more focused studies on the maturation of gait.     

Evaluation of adolescent sport specialization and injury mechanism by sex: A secondary analysis

ObjectivesThe purpose of this study was to compare the association of sport specialization with previous overuse and acute injuries between male and female adolescent athletes.DesignCross-sectional study.MethodsQuestionnaires were completed by adolescent athletes from various sports at sport club summer events in the state of Wisconsin. Adolescent athletes (12–18 years old) who were active in organized sports in the previous year were recruited. The questionnaire contained demographics, sport participation, sport specialization classification, and previous injury history. Sport specialization classification was determined using common methods in sport specialization research. Previous injury was restricted to athletic injuries that occurred in the past year.ResultsTwo-thousand and eleven participants (age = 13.7 ± 1.6 years, females = 989) completed the questionnaire. Highly specialized athletes were more likely to report both acute and overuse injuries compared to low specialization athletes. However, this relationship differed by sex, with only moderate and highly specialized females being more likely (Moderate: OR [95%CI] = 1.74 [1.18–2.58], p = 0.005; High: OR [95%CI] = 1.69 [1.14–2.53], p = 0.010) to report an overuse injury compared to low specialization females. Highly specialized female athletes were more likely to report an acute injury (High: OR [95%CI] = 1.46 [1.06–2.02], p = 0.022) compared to low specialization females. Highly specialized male athletes were not associated with overuse or acute injuries.ConclusionsHighly specialized athletes were more likely to report acute and overuse injuries. However, when this analysis was separated by sex, only highly specialized females were more likely to report a previous overuse or acute injury.     

Anaerobic capacity of elite Taiwanese Taekwondo athletes

IntroductionThis study aims to investigate anaerobic capacity with Wingate test of 11 elite male and seven elite female Taiwanese Taekwondo athletes, including Olympic gold- and silver-medalists.Synthesis of factsThe peak power, mean power, and fatigue index were 8.42 ± 0.86 (mean ± S.D.) W/kg, 6.56 ± 0.60 W/kg, and 42.17 ± 9.02%, respectively, in males, and 6.64 ± 0.42, 5.45 ± 0.88 W/kg, and 42.54 ± 19.73%, respectively, in females. The two medalists showed relatively high peak and mean power with low fatigue index.ConclusionTaiwanese Taekwondo athletes may need to improve anaerobic capacity.     

Perceived exertion responses to wheelchair propulsion differ between novice able-bodied and trained wheelchair sportspeople

ObjectivesTo investigate peripheral (RPE_P) and central (RPE_C) Ratings of Perceived Exertion during wheelchair propulsion in untrained able-bodied (AB) participants, and trained wheelchair rugby athletes with and without cervical spinal cord injury (CSCI).DesignCross-sectional study.Methods38 participants (AB: n = 20; wheelchair rugby athletes with CSCI: n = 9; without CSCI: n = 9) completed an incremental wheelchair propulsion test to exhaustion on a motorised treadmill. Gas exchange measures and heart rate (HR) were collected throughout. RPE_P and RPE_C on the Category Ratio-10 were verbally recorded each minute. Blood lactate concentration ([BLa]) was determined post-test.ResultsBetween 50–100% peak oxygen uptake (V̇O_2peak), RPE_P was greater than RPE_C in AB (p < 0.05), but not in athletes with (p = 0.07) or without (p = 0.16) CSCI. RPE_P was greater in AB compared to players with CSCI (Effect sizes: 1.24–1.62), as were respiratory exchange ratio (1.02 ± 0.10 vs 0.82 ± 0.11, p < 0.05) and [BLa]_peak (7.98 ± 2.53 vs 4.66 ± 1.57 mmol·L⁻¹). RPE_C was greater in athletes without CSCI compared to those with CSCI (Effect sizes: 0.70–1.38), as were HR (166 ± 20 vs 104 ± 15 beats·min⁻¹, p < 0.05) and ventilation (59.2 ± 28.8 vs 35.1 ± 16.6 L·min⁻¹, p = 0.01).ConclusionsRPE_P was dominant over RPE_C during wheelchair propulsion for untrained AB participants. For athletes with CSCI, lower RPE_P and RPE_C were reported at the same %V̇O_2peak compared to those without CSCI. The mechanism for this remains to be fully elucidated.