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Objective Organizational hormone effects on the human brain and behavior are often retrospectively assessed via morphological markers of prenatal (e.g., 2D:4D digit ratio) or pubertal (e.g., facial width-to-height ratio, fWHR) hormone exposure. It has been argued that markers should relate to circulating hormones particularly in challenging, dominance/status-relevant situations. However, meta-analytic research indicates that fWHR, a frequently used pubertal marker, is neither reliably sex-dimorphic nor related to steroid hormones. This casts doubt on fWHR’s validity for reflecting hormone levels. Ulna-to-fibula ratio (UFR), an alternative, long-bone-length-based pubertal marker, is sex-dimorphic and associated with dominance motivation. However, its hormonal associations were never tested before. We therefore explored UFR’s relationships to baseline and reactive hormone levels. Methods We measured ulna and fibula length as well as shoulder/waist/hip circumference of 81 participants (49 women; after exclusions) via anthropometry. Salivary hormone levels (estradiol, testosterone) at baseline and after a gross-motor one-on-one balancing contest were measured via radioimmunoassay. Results We replicated UFR’s dimorphism, unrelatedness to height, and correlations to other putative markers of organizational hormone effects. On an exploratory basis, we found UFR to be related to overall baseline testosterone and to competition-induced reactive surges in steroid hormones (estradiol, testosterone) overall and in women. Conclusions Our results hint at UFR’s relationship to baseline testosterone and may indicate functional connections between outcomes of pubertal organizational hormone effects and contest-induced steroid reactivity. Pubertal organizational hormone effects may prepare the endocrine system for dominance and status contests. However, the small sample and the exploratory nature of our research demands replication.

Background Team-sport players have a particularly high injury risk. Although female sex is considered a risk factor, it is still unknown whether female and male team-sport players, in fact, differ in their injury rates. We aimed to compare injury rates between female and male players by systematically reviewing and meta-analyzing injury surveillance studies of both sexes in order to evaluate sex-specific differences in team-sport injuries. Methods Studies that prospectively collected injury data for high-level female and male players (age ≥16 years) in basketball, field hockey, football (soccer), handball, rugby (union and sevens), and volleyball were included. Two reviewers (AZ and AL) independently assessed study quality and extracted data for overall, match, training, and severe injuries (>28 days’ time loss) as well as data regarding injury locations and types. Incidence rate ratios (IRRs) were pooled in a meta-analysis, and meta-regression analysis was performed when 10 or more studies were available. Results Of 20 studies, 9 studies reported injury data from football, 3 studies from rugby, 3 studies from handball, 1 study from basketball, 1 study from field hockey, 2 studies from volleyball, and 1 study from basketball and field hockey. For overall injuries, the pooled IRR (0.86; 95% confidence interval (95%CI): 0.76−0.98) indicated significantly more injuries in male than in female players. For injury location, the pooled IRR showed higher injury rates in male athletes than in female athletes for upper extremity, hip/groin, thigh, and foot injuries. Female players had a significantly higher rate of anterior cruciate ligament injuries (IRR = 2.15, 95%CI: 1.27−3.62) than male players. No significant sex-specific differences in IRR were found for match, training, severe injuries, concussions, or ankle sprains. Conclusion Our meta-analysis provides evidence for sex-specific differences in the injury rates in team sports. Further epidemiological studies including both sexes in sports other than football are needed in order to strengthen the evidence.

We examine the novel hypothesis that physical exercise and sleep have synergistic effects on memory. Exercise can trigger mechanisms that can create an optimal brain state during sleep to facilitate memory processing. The possibility that exercise could counteract the deleterious effects of sleep deprivation on memory by protecting neuroplasticity also is discussed.

The ability to acquire and retain motor skills is essential for persons with Parkinson’s Disease (PD), who usually experience a progressive loss of mobility during the disease. Deficits in the rate of motor skill acquisition have been previously reported in these patients. Whether motor skill retention is also impaired is currently not known. We conducted a review that included 46 studies to determine whether, compared with neurologically intact individuals, motor skill retention is impaired in PD. Meta-analyses revealed that, following a single practice session, persons with PD have deficits in skill retention (SMD = −0.17; 95% CI = −0.32, −0.02;p= 0.0225). However, these deficits are task-specific, affecting sensory motor (SMD = −0.31; 95% CI −0.47, −0.15;p= 0.0002) and visuomotor adaptation (SMD = − 1.55; 95% CI = −2.32, −0.79;p= 0.0001) tasks, but not sequential fine motor (SMD = 0.17; 95% CI = −0.05, 0.39;p= 0.1292) and gross motor tasks (SMD = 0.04; 95% CI = −0.25, 0.33;p= 0.7771). Importantly, retention deficits became non-significant when augmented feedback during practice was provided. Similarly, additional sessions of motor practice restored the deficits observed in sensory motor tasks. Meta-regression analyses confirmed that retention deficits were independent of performance during motor skill acquisition, as well as the duration and severity of the disease. These results are in line with prominent neurodegenerative models of PD progression and emphasize the importance of developing targeted interventions to enhance motor memory processes supporting the retention of motor skills in people with PD.

High-intensity cardiovascular exercise prior to motor skill practice is postulated to enhance motor memory consolidation (offline learning), whereas moderate-intensity bouts may benefit skill acquisition (online learning). This study aimed at investigating this suggested intensity-dependent effect of exercise in a complex whole-body task. 50 healthy young adults were randomized into one of three groups performing a bout of either (1) high-intense, (2) moderate-intense, or (3) minimal-intense cycling for a total of 17 min immediately prior to skill practice. The motor task required participants to balance on a tiltable platform (stabilometer) for 30 s. During acquisition 15 practice trials were carried out, followed by a retention test 24 h later. Time in balance was calculated for each trial and within- and between-group differences in online (skill improvement during skill acquisition) and offline learning (skill change from last acquisition block to retention) were analyzed. All participants significantly improved balance time during acquisition, with no differences observed between experimental conditions. Similarly, there were no differences in offline learning between groups. Contrary to previous reports, the present data do not support an intensity-dependent effect on motor learning, when exercise is performed prior to task practice. One reason for this might be that similar muscle groups were involved in exercise and the motor task, potentially causing fatigue or interference effects. Further, the results indicate that the memory-promoting effects of acute exercise are task-dependent and may not apply equally for motor skills of different levels of complexity.

Gait impairment is a major motor symptom in Parkinson's disease (PD), and treadmill training is an effective non-pharmacological treatment option.In this study, the time course, sustainability and transferability of gait adaptations to treadmill training with and without additional postural perturbations were investigated.38 PD patients (HoehnYahr 1-3.5) were randomly allocated to eight weeks of treadmill training, performed twice-weekly for 40 min either with (perturbation treadmill training [PTT], n = 18) or without (conventional treadmill training [CTT], n = 20) additional perturbations to the treadmill surface. Spatiotemporal gait parameters were assessed during treadmill walking on a weekly basis (T0-T8), and after three months follow-up (T9). Additional overground gait analyses were performed at T0 and T8 to investigate transfer effects.Treadmill gait variability reduced linearly over the course of 8 weeks in both groups (p .001; Cohen's d (range): -0.53 to -0.84). Only the PTT group significantly improved in other gait parameters (stride length/time, stance-/swing time), with stride time showing a significant between-group interaction effect (Cohen's d = 0.33; p = .05). Additional between-group interactions indicated more sustained improvements in stance (Cohen's d = 0.85; p = .02) and swing time variability in the PTT group (Cohen's d = 0.82; p = .03) at T9. Overground gait improvements at T8 existed only in stance (d = -0.73; p = .04) and swing time (d = 0.73; p = .04).Treadmill stride-to-stride variability reduced substantially and linearly, but transfer to overground walking was limited. Adding postural perturbations tended to increase efficacy and sustainability of several gait parameters. However, since between-group effects were small, more work is necessary to support these findings.

Background: Individuals with chronic ankle instability (CAI) demonstrate altered ankle kinematics during running compared to uninjured individuals; however, little is known about differences between individuals with CAI and those who recover successfully from an index sprain (copers). Methods: Thirty-two young male athletes with prior ankle sprain were investigated, eighteen with CAI and fourteen copers. Instrumented running analysis was performed on a treadmill at two velocities: moderate (2.63 ± 0.20 m/s, rate of perceived of exertion = 14/20); and high velocity (3.83 ± 0.20 m/s). Mean ankle kinematics and stride-to-stride variability were analyzed applying the statistical parametric mapping method. Results: At both running velocities, no statistically significant differences in mean ankle kinematics were observed. At high running velocity, athletes with CAI demonstrated significantly increased frontal plane variability at 17–19% of the running gait cycle (p = 0.009). Additionally, large between-group effect sizes (Hedges’ g ≥ 0.8) may potentially indicate increased frontal plane variability during initial contact and terminal swing, as well as decreased variability in sagittal plane at 34–35% in CAI. A similar tendency existed at moderate velocity, with large effect sizes indicating decreased dorsiflexion at 75–89% in CAI, as well as an increased frontal plane variability at 16–25%, and 97–99%. Discussion: Compared to copers, individuals with CAI demonstrate increased variability of ankle kinematics - mainly in the frontal plane and particularly during stance phase - while mean ankle kinematics seems minimally affected. Increased ankle variability at high running velocity may best reflect persisting sensorimotor control deficits in athletes with chronically instable ankles.

BackgroundRunning is a popular sport with high injury rates. Although risk factors have intensively been investigated, synthesized knowledge about the differences in injury rates of female and male runners is scarce.ObjectiveTo systematically investigate the differences in injury rates and characteristics between female and male runners.MethodsDatabase searches (PubMed, Web of Science, PEDro, SPORTDiscus) were conducted according to PRISMA guidelines using the keywords “running AND injur*”. Prospective studies reporting running related injury rates for both sexes were included. A random-effects meta-analysis was used to pool the risk ratios (RR) for the occurrence of injuries in female vs. male runners. Potential moderators (effect modifiers) were analysed using meta-regression.ResultsAfter removal of duplicates, 12,215 articles were screened. Thirty-eight studies were included and the OR of 31 could be pooled in the quantitative analysis. The overall injury rate was 20.8 (95% CI 19.9–21.7) injuries per 100 female runners and 20.4 (95% CI 19.7–21.1) injuries per 100 male runners. Meta-analysis revealed no differences between sexes for overall injuries reported per 100 runners (RR 0.99, 95% CI 0.90–1.10,n = 24) and per hours or athlete exposure (RR 0.94, 95% CI 0.69–1.27,n = 6). Female sex was associated with a more frequent occurrence of bone stress injury (RR (for males) 0.52, 95% CI 0.36–0.76,n = 5) while male runners had higher risk for Achilles tendinopathies (RR 1. 86, 95% CI 1.25–2.79,n = 2). Meta-regression showed an association between a higher injury risk and competition distances of 10 km and shorter in female runners (RR 1.08, 95% CI 1.00–1.69).ConclusionDifferences between female and male runners in specific injury diagnoses should be considered in the development of individualised and sex-specific prevention and rehabilitation strategies to manage running-related injuries.

Emerging evidence indicates that acute bouts of cardiovascular exercise promote motor memory formation. In this preregistered meta-analysis (CRD42018106288) we synthesize data from 22 studies published until February 2020, including a total of 862 participants. We calculated standardized mean differences (SMDs) with 95 % confidence intervals (CIs) to assess exercise effects on motor memory encoding and consolidation, respectively. The pooled data indicate that exercise mainly benefits the consolidation of memories, with exercise prior to motor practice improving early non-sleep consolidation (SMD, 0.58; 95 % CI, 0.30-0.86; p < 0.001), and post-practice exercise facilitating sleep-dependent consolidation (SMD, 0.62; 95 % CI, 0.34-0.90; p < 0.001). Strongest effects exist for high exercise intensities, and motor task nature appears to be another relevant modulator. We demonstrate that acute cardiovascular exercise particularly promotes the consolidation of acquired motor memories, and exercise timing, and intensity as well as motor task nature seem to critically modulate this relationship. These findings are discussed within currently proposed models of motor memory formation and considering molecular and systemic mechanisms of neural plasticity.

Background and purpose Perturbation training is a promising approach to reduce fall incidence in persons with Parkinson disease (PwPD). This study aimed to evaluate interindividual differences in balance adaptations in response to perturbation treadmill training (PTT) and identify potential outcome predictors. Methods PwPD (n = 43, Hoehn & Yahr stage 1-3.5) were randomly assigned to either 8 weeks of PTT or conventional treadmill training (CTT) without perturbations. At baseline and following intervention, data from 4 domains of balance function (reactive, anticipatory, dynamic postural control, and quiet stance) were collected. Using responder analysis we investigated interindividual differences (responder rates and magnitude of change) and potential predictive factors. Results PTT showed a significantly higher responder rate in the Mini Balance Evaluation Systems Test (Mini-BESTest) subscore reactive postural control, compared with CTT (PTT = 44%; CTT = 10%; risk ratio = 4.22, confidence interval = 1.03-17.28). Additionally, while between-groups differences were not significant, the proportion of responders in the measures of dynamic postural control was higher for PTT compared with CTT (PTT: 22%-39%; CTT: 5%-10%). The magnitude of change in responders and nonresponders was similar in both groups. PTT responders showed significantly lower initial balance performance (4/8 measures) and cognitive function (3/8 measures), and were older and at a more advanced disease stage, based on descriptive evaluation. Discussion and conclusions Our findings suggest that PTT is beneficial to improve reactive balance in PwPD. Further, PTT appeared to be effective only for a part of PwPD, especially for those with lower balance and cognitive function, which needs further attention.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A1).

Background Impaired gait and postural stability are cardinal motor symptoms in Parkinson's disease (PD). Treadmill training improves gait characteristics in PD. Objective This study investigates if postural perturbations during treadmill training improve motor performance and particularly gait and postural stability in PD. Methods This work presents secondary outcome measures of a pilot randomized controlled trial. PD patients (n = 43) recruited at the University Hospital Erlangen were randomly allocated to the experimental (perturbation treadmill training, PTT, n = 21) or control group (conventional treadmill training, CTT, n = 22). Outcome measures were collected at baseline, after 8 weeks of intervention, and 3 months follow-up. Motor impairment was assessed by the Unified Parkinson Disease Rating Scale part-III (UPDRS-III), Postural Instability and Gait Difficulty score (PIGD), and subitems 'Gait' and 'Postural stability' by an observer blinded to the randomization. Intervention effects were additionally compared to progression rates of a matched PD cohort (n = 20) receiving best medical treatment (BMT). Results Treadmill training significantly improved UPDRS-III motor symptoms in both groups with larger effect sizes for PTT (-38%) compared to CTT (-20%). In the PTT group solely, PIGD -34%, and items 'Gait' -50%, and 'Postural stability' -40% improved significantly in comparison to CTT (PIGD -24%, 'Gait' -22%, 'Postural stability' -33%). Positive effects persisted in PTT after 3 months and appeared to be beneficial compared to BMT. Conclusions Eight weeks of PTT showed superior improvements of motor symptoms, particularly gait and postural stability. Sustainable effects indicate that PTT may be an additive therapy option for gait and balance deficits in PD.

Acute cardiovascular exercise has shown to promote neuroplastic processes, and thus to improve the consolidation of newly acquired motor skills in healthy adults. First results suggest that this concept may be transferred to populations with motor and cognitive dysfunctions. In this context, Parkinson’s disease (PD) is highly relevant since patients demonstrate deficits in motor learning. Hence, in the present study we sought to explore the effect of a single post-practice exercise bout on motor memory consolidation in PD patients.For this purpose, 17 PD patients (Hoehn and Yahr: 1 – 2.5, age: 60.1 ± 7.9 y) practiced a whole-body task followed by either (i) a moderate-intense bout of cycling, or (ii) seated rest for a total of 30 minutes. The motor task required the participants to balance on a tiltable platform (stabilometer) for 30 seconds. During skill practice, patients performed 15 trials followed by a retention test 1 day and 7 days later. We calculated time in balance (platform within ± 5° from horizontal) for each trial and within- and between-group differences in memory consolidation (i.e. offline learning = skill change from last acquisition block to retention tests) were analyzed.Groups revealed similar improvements during skill practice (F4,60 = .316, p = .866), but showed differences in offline learning, which was only evident after 7 days (F1,14 = 5.602, p = .033).Our results suggest that a single post-practice exercise bout is effective in enhancing long-term motor memory consolidation in a population with motor learning impairments. This may point at unique promoting effects of exercise on dopamine neurotransmission involved in memory formation. Future studies should investigate the potential role of exercise-induced effects on the dopaminergic system.HighlightsAcute exercise enhanced motor memory consolidation in PDEffects were evident only at 7-day retentionResults may indicate unique exercise-effects on the dopaminergic systemFindings show promising potential of exercise for motor rehabilitation

The aim of this retrospective cohort study is to investigate the association between different subjective and objective assessments of ankle function in a population of athletes with or without functional ankle instability (FAI). 29 athletes with a history of ankle spraining were divided into two groups according to their ankle status: 16 with FAI (initial ankle sprain with residual functional instability) (age 24.6 ± 3.1 years), and 13 COPERS (initial ankle sprain without residual instability) (age 25.3 ± 4.4 years). The assessment of each individual's ankle function was based on three approaches: The "functional-ankle-ability-measure" (FAAM) assessing subjective ankle functionality, measures of sensorimotor control as objective functional measurements and MRI-based T2-mapping as a quantitative marker of compositional joint status. Pearson's product-moment-correlation coefficient, student's t-test and analysis-of-variance were used for statistical analysis. Significant group differences existed for subjective ankle function (FAAM, p = 0.04) and MRI-data mainly in the medial compartment of the ankle joint (p ≤ 0.05). We found unique associations between T2-mapping results and sensorimotor scores in the COPER (r = -0.756-0.849), and "FAI"-group (r = 0.630-0.657). The location and magnitude differed between groups. No correlations existed between these measures and the FAAM. This exploratory study provides preliminary evidence for potential interrelations between various diagnostic measures of ankle function and structure in individuals with and without FAI. We found associations between MRI-results and selected measures of sensorimotor control, indicating a potential link between loss of ankle function and early joint degeneration. Despite these interrelations, each of the different assessment options appears to contain unique information on ankle functionality important in a clinical assessment.

Distorsionen des oberen Sprunggelenks stellen mit einer Pravalenz von 25–30 % aller Sportunfalle neben dem Kniegelenk die am haufigsten betroffene Korperregion dar. Mindestens ein Drittel aller Betroffenen entwickelt eine chronische Gelenkinstabilitat mit anhaltenden Beschwerden, die jedoch in vielen Fallen nicht auf eine mechanische Insuffizienz des Kapsel-Band-Apparats zuruckzufuhren ist. Hierfur wurde der Begriff der funktionellen Sprunggelenkinstabilitat gepragt. Als Ursache werden Storungen des sensomotorischen Systems vermutet. Dazu zahlen u. a. Beeintrachtigungen der Propriozeption, der posturalen Kontrolle sowie der Kraft und Reflexaktivitat der gelenkumgebenden Muskulatur. Im vorliegenden Ubersichtsbeitrag wird die aktuelle Studienlage hinsichtlich sensomotorischer Defizite bei funktioneller Sprunggelenkinstabilitat aufgearbeitet. Die Ergebnisse werden vor dem Hintergrund neuerer neurophysiologischer Modelle zur Entstehung von Gelenkinstabilitaten diskutiert.

Background. Gait and balance dysfunction are major symptoms in Parkinson’s disease (PD). Treadmill training improves gait characteristics in this population but does not reflect the dynamic nature of controlling balance during ambulation in everyday life contexts. Objective. To evaluate whether postural perturbations during treadmill walking lead to superior effects on gait and balance performance compared with standard treadmill training. Methods. In this single-blind randomized controlled trial, 43 PD patients (Hoehn & Yahr stage 1-3.5) were assigned to either an 8-week perturbed treadmill intervention (n = 21) or a control group (n = 22) training on the identical treadmill without perturbations. Patients were assessed at baseline, postintervention, and at 3 months’ follow-up. Primary endpoints were overground gait speed and balance (Mini-BESTest). Secondary outcomes included fast gait speed, walking capacity (2-Minute Walk Test), dynamic balance (Timed Up-and-Go), static balance (postural sway), and balance confidence (Activities-Specific Balance Confidence [ABC] scale). Results. There were no significant between-group differences in change over time for the primary outcomes. At postintervention, both groups demonstrated similar improvements in overground gait speed ( P = .009), and no changes in the Mini-BESTest ( P = .641). A significant group-by-time interaction ( P = .048) existed for the Timed Up-and-Go, with improved performance only in the perturbation group. In addition, the perturbation but not the control group significantly increased walking capacity ( P = .038). Intervention effects were not sustained at follow-up. Conclusions. Our primary findings suggest no superior effect of perturbation training on gait and balance in PD patients. However, some favorable trends existed for secondary gait and dynamic balance parameters, which should be investigated in future trials.

Summary Objective The aim of this study was to investigate, using T2-mapping, the impact of functional instability in the ankle joint on the development of early cartilage damage. Methods Ethical approval for this study was provided. Thirty-six volunteers from the university sports program were divided into three groups according to their ankle status: functional ankle instability (FAI, initial ankle sprain with residual instability); ankle sprain Copers (initial sprain, without residual instability); and controls (without a history of ankle injuries). Quantitative T2-mapping magnetic resonance imaging (MRI) was performed at the beginning (‘early-unloading') and at the end (‘late-unloading') of the MR-examination, with a mean time span of 27 min. Zonal region-of-interest T2-mapping was performed on the talar and tibial cartilage in the deep and superficial layers. The inter-group comparisons of T2-values were analyzed using paired and unpaired t -tests. Statistical analysis of variance was performed. Results T2-values showed significant to highly significant differences in 11 of 12 regions throughout the groups. In early-unloading, the FAI-group showed a significant increase in quantitative T2-values in the medial, talar regions ( P = 0.008, P = 0.027), whereas the Coper-group showed this enhancement in the central-lateral regions ( P = 0.05). Especially the comparison of early-loading to late-unloading values revealed significantly decreasing T2-values over time laterally and significantly increasing T2-values medially in the FAI-group, which were not present in the Coper- or control-group. Conclusion Functional instability causes unbalanced loading in the ankle joint, resulting in cartilage alterations as assessed by quantitative T2-mapping. This approach can visualize and localize early cartilage abnormalities, possibly enabling specific treatment options to prevent osteoarthritis in young athletes.

Background Sensorimotor control is permanently impaired following functional ankle instability and temporarily decreased following fatigue. Little is known on potential interactions between both conditions. The purpose was to investigate the effect of fatiguing exercise on sensorimotor control in athletes with and without (coper, controls) functional ankle instability. Methods 19 individuals with functional ankle instability, 19 ankle sprain copers, and 19 non-injured controls participated in this cohort study. Maximum reach distance in the star excursion balance test, unilateral jump landing stabilization time, center of pressure sway velocity in single-leg-stance, and passive ankle joint position sense were assessed before and immediately after fatiguing treadmill running. A three factorial linear mixed model was specified for each outcome to evaluate the effects of group, exhausting exercise (fatigue) and their interactions (group by fatigue). Effect sizes were calculated as Cohen's d. Findings Maximum reach distance in the star excursion balance test, jump stabilization time and sway velocity, but not joint position sense, were negatively affected by fatigue in all groups. Effect sizes were moderate, ranging from 0.27 to 0.68. No significant group by fatigue interactions were found except for one measure. Copers showed significantly larger prefatigue to postfatigue reductions in anterior reach direction ( P ≤ 0.001; d = − 0.55) compared to the ankle instability ( P = 0.007) and control group ( P = 0.052). Interpretation Fatiguing exercise negatively affected postural control but not proprioception. Ankle status did not appear to have an effect on fatigue-induced sensorimotor control impairments.

Context: Sensorimotor control is impaired after ankle injury and in fatigued conditions. However, little is known about fatigue-induced alterations of postural control in athletes who have experienced an ankle sprain in the past. Objective: To investigate the effect of fatiguing exercise on static and dynamic balance abilities in athletes who have successfully returned to preinjury levels of sport activity after an ankle sprain. Design: Cohort study. Setting: University sport science research laboratory. Patients or Other Participants: 30 active athletes, 14 with a previous severe ankle sprain (return to sport activity 6–36 months before study entry; no residual symptoms or subjective instability) and 16 uninjured controls. Intervention(s): Fatiguing treadmill running in 2 experimental sessions to assess dependent measures. Main Outcome Measure(s): Center-of-pressure sway velocity in single-legged stance and time to stabilization (TTS) after a unilateral jump-landing task (session 1) and maximum reach distance in the Star Excursion Balance Test (SEBT) (session 2) were assessed before and immediately after a fatiguing treadmill exercise. A 2-factorial linear mixed model was specified for each of the main outcomes, and effect sizes (ESs) were calculated as Cohen d. Results: In the unfatigued condition, between-groups differences existed only for the anterior-posterior TTS (P = .05, ES = 0.39). Group-by-fatigue interactions were found for mean SEBT (P = .03, ES = 0.43) and anterior-posterior TTS (P = .02, ES = 0.48). Prefatigue versus postfatigue SEBT and TTS differences were greater in previously injured athletes, whereas static sway velocity increased similarly in both groups. Conclusions: Fatiguing running significantly affected static and dynamic postural control in participants with a history of ankle sprain. Fatigue-induced alterations of dynamic postural control were greater in athletes with a previous ankle sprain. Thus, even after successful return to competition, ongoing deficits in sensorimotor control may contribute to the enhanced ankle reinjury risk.

The study investigates immediate adaptations of gait and balance to a single session of perturbed treadmill walking in patients with Parkinson's disease. 39 Parkinson's patients in stage 1-3.5 of the Hoehn and Yahr Scale were randomized into one of two groups, stratified by disease severity: The experimental group (n=19) walked on a treadmill prototype which constantly applied perturbation by small three-dimensional tilting movements of the walking surface. The control group (n=20) trained on the identical treadmill without perturbations. Patients walked on the treadmill for 20min. Primary outcome measure was overground walking speed. Secondary outcomes were postural sway during quiet standing and spatiotemporal gait parameters during treadmill walking. Outcomes were measured repeatedly throughout the training session and after 10min retention. The experimental group significantly increased overground walking speed after intervention compared to the control group (p=0.014; ES=+0.41). Gait variability during treadmill walking significantly decreased after walking with perturbation. Sway area increased with treadmill walking only in the control group (p=0.009; ES=+0.49). No other postural sway measures changed over time. Subgroup analyses revealed that in the experimental group patients with more pronounced motor impairment demonstrated larger increases in overground walking speed (p=0.016; ES=+0.40) and stance phase symmetry (p=0.011; ES=-0.42). In conclusion, a single session of perturbation treadmill training led to gait improvements, which were more pronounced compared to unperturbed treadmill walking. Effects on static postural sway were less pronounced.

In Deutschland fehlen einheitliche Standards fur Nachsorgemasnahmen bei Schlaganfallpatienten. Ziel dieser Arbeit ist es, den aktuellen Forschungsstand hinsichtlich der Inhalte und Wirksamkeit bewegungs-/physio- und ergotherapeutischer Nachsorgemasnahmen und deren geeignete Dosis (Intensitat, Dauer, Haufigkeit) zusammenzufassen. Bewegungstherapeutische Masnahmen (u. a. Physiotherapie, Kraft-, Ausdauer-, Gangtraining) zeigen gute Ergebnisse hinsichtlich der Verbesserung korperlicher Funktionen (muskulare-, kardiopulmonale Leistungsfahigkeit, motorische Funktion), die sich besonders gunstig auf die Gehfahigkeit, Mobilitat und Alltagsfunktion der Schlaganfallpatienten auswirken. Ergotherapie zeigt ebenfalls eine gute Wirksamkeit, besonders wenn es um die Wiederherstellung der Alltagsfahigkeit und die Wiederaufnahme von sozialen und freizeitbezogenen Aktivitaten geht. Weitere Untersuchungen sind notig, um die spezifischen Wirkmechanismen der einzelnen Therapiestrategien und deren geeignete Dosis klarer zu differenzieren und somit eine gezielte Verordnung zu erleichtern.

The behavior of aponeuroses during voluntary contractions is still poorly understood and results provided in the literature are controversial. Therefore, the aim of this study was to investigate the behavior of the tibialis anterior aponeurosis during passive movements and active isometric, concentric, and eccentric contractions in vivo. Based on previous findings, we hypothesized that the aponeurosis exhibits behavior that is not consistent with a serial alignment with the contractile element of the muscle. Nine subjects participated in the study and performed contractions on a Biodex-dynamometer. Two ultrasound probes were used to visualize the proximal and distal ends of the tibialis anterior aponeurosis from which length changes were calculated. The main findings were that: (1) During isometric contractions, aponeurosis lengths increased and decreased with increasing and decreasing forces by about 2.8 (±1.5) mm while tendon length changes were much greater and averaged 15 (±3.3) mm, (2) during passive movements, aponeurosis lengths did not change significantly, and (3) despite similar average torque changes during concentric and eccentric contractions, aponeurosis lengths changed by 2.2 mm in concentric but only by 1.2 mm in eccentric contractions. The results of this study did not provide clear evidence for or against a serial alignment of the aponeurosis with the contractile elements. However, at low activation levels during force ramp contractions, there was a small but consistent shortening of aponeuroses with increasing torque. Our findings suggest that aponeurosis length changes do not depend on force alone but depend critically on activation level and the type of contraction.

Zech A, Steib S, Freiberger E, Pfeifer K. Functional muscle power testing in young, middle-aged, and community-dwelling nonfrail and prefrail older adults. Objective To evaluate the stair climb (SC) and sit-to-stand (STS) transfer test for functional power assessment in young, middle-aged, and community-dwelling nonfrail and prefrail older adults. Design Cross-sectional study. Setting Sport science institute providing health-related exercise programs for older people. Participants Participants (N=60; age, 22–81y) were divided into groups of young (n=15; 20–30y), middle-aged (n=16; 40–60y), nonfrail older (n=16; >65y), and prefrail older adults (n=13; >65y). Interventions Not applicable. Main Outcome Measures SC and STS transfer power were measured on 2 separate occasions. Results Age and height correlated positively ( P R 2 ) of the variance in SC power and 31.3% ( R 2 ) of the variance in STS transfer power can be attributed to age and height. Significant age-related subgroup differences were found for SC power ( P =.001). Nonfrail and prefrail older adults differed significantly in both power measures ( P Conclusions The findings indicate that SC and STS transfer power are sensitive enough to distinguish between nonfrailty and prefrailty. This suggests that both tests are relevant clinical measures in older people.

The purpose of this study was to determine the dose-response relationship of resistance training (RT) to improve strength and function in older adults.A systematic literature search was performed in relevant databases and study reference lists to identify randomized controlled trials. Randomized controlled trials comparing the effects of different doses of strength training in older people (65 yr and older) on strength and functional outcomes were eligible. Two independent reviewers decided on study inclusion, extracted data, and assessed methodological quality. Standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated for relevant outcomes and pooled using a random-effects model.Twenty-nine trials with a total of 1313 subjects (mean age = 65-81 yr) are summarized in this review. Trials comparing different training intensities show strong effects of progressive resistance training (PRT) on maximal strength in a dose-dependent manner, with high-intensity (HI) PRT being more effective compared with moderate (MI)- and low-intensity (LI) PRT (SMD [HI vs LI] = 0.88, 95% CI = 0.21-1.55; SMD [HI vs MI] = 0.62, 95% CI = 0.22-1.03). PRT was also successful for improving functional outcomes, but gains were independent of training intensity. Power training (PT) was more effective for improving muscle power (SMD [PT vs PRT] = 1.66, 95% CI = 0.08-3.24) and functional outcomes than PRT. There was only little information available on training volume and frequency.Higher training intensities are superior to lower intensities for improving maximal strength but not necessarily for functional performance of older adults. PT has shown to be a particularly effective method for enhancing muscle power and functional performance. More research is necessary to identify the effect of different training volumes and frequencies and the dose-response relationship for very old and frail populations.

When an isometrically activated muscle is stretched or shortened the isometric steady-state force after the length change is increased (residual force enhancement) or decreased (force depression), respectively compared to a purely isometric contraction. This behavior has been observed consistently from the single sarcomere to the whole muscle level. However, the results for voluntary contractions in vivo are controversial and there are no studies for maximal voluntary contractions of medium sized muscles like the human ankle dorsiflexors. We investigated the effect of active muscle stretching and shortening for in vivo human tibialis anterior (n = 12) for maximal voluntary contractions for two magnitudes of stretching (15 degrees and 30 degrees) and two speeds of contraction (10 degrees/s and 45 degrees/s). Torques during stretches were higher compared to the purely isometric reference contractions and peak torques occurred prior to the end of the stretch. During the stretch, muscular activity decreased after peak torque had been reached for the high speed stretch experiments. In the steady-state phase following stretch, torque was increased for all experimental conditions but not for all time periods following stretch. The amount of residual force enhancement was independent of amplitude and speed of stretch. In the steady-state phase following shortening, torques were decreased compared to the isometric reference contractions and force depression was increased with increasing speeds of shortening.

Exercise therapy is a common intervention for improving postural stability. The purpose of this meta-analysis was to assess the effect of exercise therapy on postural instability in persons with Parkinson disease (PD) based on the available literature, and to evaluate the efficacy across various types of exercise interventions.In January 2015, electronic databases (PubMed, Scopus, PEDro) and study reference lists were searched for randomized controlled trials with moderate or high methodological quality (PEDro score ≥ 5), investigating the effect of exercise on postural instability in persons with PD.Three reviewers extracted data and assessed quality.Postural stability as measured using the Berg Balance Scale, postural sway, Timed Up and Go, or Functional Reach test. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated.Twenty-two trials, with a total of 1072 participants, were eligible for inclusion. The pooled estimates of effects showed significantly improved postural instability (SMD, 0.23; 95% CI, 0.10-0.36; P0.001) after exercise therapy, in comparison with no exercise or sham treatment. Exercise interventions specifically addressing components of balance dysfunction demonstrated the largest efficacy, with moderate to high effect sizes (SMD, 0.43; 95% CI, 0.21-0.66; P0.001). Little or no beneficial effects were observed for interventions not specifically targeted at postural stability (SMD, 0.20; 95% CI -0.04 to 0.44; P = 0.11) or for home-based, multicomponent exercise programs (SMD, 0.02; 95% CI -0.20 to 0.25; P = 0.86).Exercise therapies specifically addressing balance dysfunction are an important treatment option for improving postural stability in persons with PD. Future studies should investigate sustainability of the short-term effects and establish the dose-response relationship of balance training in persons with PD.Video abstract available for additional insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A121).

The aim of this retrospective cohort study is to investigate the association between different subjective and objective assessments of ankle function in a population of athletes with or without functional ankle instability (FAI). 29 athletes with a history of ankle spraining were divided into two groups according to their ankle status: 16 with FAI (initial ankle sprain with residual functional instability) (age 24.6 ± 3.1 years), and 13 COPERS (initial ankle sprain without residual instability) (age 25.3 ± 4.4 years). The assessment of each individual's ankle function was based on three approaches: The "functional-ankle-ability-measure" (FAAM) assessing subjective ankle functionality, measures of sensorimotor control as objective functional measurements and MRI-based T2-mapping as a quantitative marker of compositional joint status. Pearson's product-moment-correlation coefficient, student's t-test and analysis-of-variance were used for statistical analysis. Significant group differences existed for subjective ankle function (FAAM, p = 0.04) and MRI-data mainly in the medial compartment of the ankle joint (p ≤ 0.05). We found unique associations between T2-mapping results and sensorimotor scores in the COPER (r = -0.756-0.849), and "FAI"-group (r = 0.630-0.657). The location and magnitude differed between groups. No correlations existed between these measures and the FAAM. This exploratory study provides preliminary evidence for potential interrelations between various diagnostic measures of ankle function and structure in individuals with and without FAI. We found associations between MRI-results and selected measures of sensorimotor control, indicating a potential link between loss of ankle function and early joint degeneration. Despite these interrelations, each of the different assessment options appears to contain unique information on ankle functionality important in a clinical assessment.

Injury prevention effects of neuromuscular training have been partly attributed to postural control adaptations. Uncertainty exists regarding the magnitude of these adaptations and on how they can be adequately monitored. The objective was to determine the time course of neuromuscular training effects on functional, dynamic and static balance measures. Thirty youth (14.9 ± 3 years) field hockey athletes were randomised to an intervention or control group. The intervention included a 20-min neuromuscular warm-up program performed twice weekly for 10 weeks. Balance assessments were performed at baseline, week three, week six and post-intervention. They included the star excursion balance test (SEBT), balance error scoring system (BESS), jump-landing time to stabilization (TTS) and center of pressure (COP) sway velocity during single-leg standing. No baseline differences were found between groups in demographic data and balance measures. Adherence was at 86 %. All balance measures except the medial–lateral TTS improved significantly over time (p

Stroke is one of the major public health concerns throughout the world. It is a leading cause of long-term disability (Shah, 2006), consuming a large amount of health care resources. In Western Europe, the incidence varies between 1.0 and 3.75 per 1000 habitants (Weir et al., 2001). The proportion of patients who die or are dependent at six months after stroke ranges from 20 – 41% (Brainin et al., 2000). The consequences after stroke are not only persistent neurological impairment which lead to physical,functional and psychosocial problems, but also life-time disability that requires rehabilitation to enable optimal function. There is strong evidence that specialized interdisciplinary stroke rehabilitation units are correlated with improved functional outcomes, mortality reduction, shorter lengths of hospital stay, and reduced need for long term institutionalization in moderate to severe stroke patients (Teasell et al., 2009). The benefits of specialized interdisciplinary stroke rehabilitation can be attributed to the fact that they emphasize specialized training for stroke rehabilitation inpatients, while an emphasis on working as a complementary rehab team ensures that diverse skills can be applied to deal with the complex needs of the stroke patient. Specialized interdisciplinary stroke rehabilitation units currently represent the “gold standard” in stroke rehabilitative care (Teasell et al., 2009). There are many specialized interdisciplinary stroke rehabilitation units, running throughout the European countries. Regarding the concepts of Health care provision which is composed of structures of care, processes of care, and outcomes (Donabedian, 1988), each organized stroke rehabilitation centre has its own practice ( structure of care and process of care) which will effect on its outcome and make a difference to other centres. Therefore, comparing different stroke

In team sports, sensorimotor impairments resulting from previous injuries or muscular fatigue have been suggested to be factors contributing to an increased injury risk. Although it has been widely shown that physical fatigue affects static postural sway, it is still questionable as to what extent these adaptations are relevant for dynamic, sports-related situations. The objective of this study was to determine the effects of whole-body and localized fatigue on postural control in stable and unstable conditions. Nineteen male team handball players were assessed in 2 sessions separated by 1 week. Treadmill running and single-leg step-up exercises were used to induce physical fatigue. The main outcome measures were center of pressure (COP) sway velocity during a single-leg stance on a force plate and maximum reach distances of the star excursion balance test (SEBT). The COP sway velocity increased significantly (p < 0.05) after general (+47%) and localized fatigue (+10%). No fatigue effects were found for the SEBT. There were no significant correlations between COP sway velocity and SEBT mean reach in any condition. The results showed that although fatigue affects static postural control, sensorimotor mechanisms responsible for regaining dynamic balance in healthy athletes seem to remain predominantly intact. Thus, our data indicate that the exclusive use of static postural sway measures might not be sufficient to allow conclusive statements regarding sensorimotor control in the noninjured athlete population.

Force enhancement following muscle stretching and force depression following muscle shortening are well-accepted properties of skeletal muscle contraction. However, the factors contributing to force enhancement/depression remain a matter of debate. In addition to factors on the fiber or sarcomere level, fiber length and angle of pennation affect the force during voluntary isometric contractions in whole muscles. Therefore, we hypothesized that differences in fiber lengths and angles of pennation between force-enhanced/depressed and reference states may contribute to force enhancement/depression during voluntary contractions. The purpose of this study was to test this hypothesis. Twelve subjects participated in this study, and force enhancement/depression was measured in human tibialis anterior. Fiber lengths and angles of pennation were quantified using ultrasound imaging. Neither fiber lengths nor angles of pennation were found to differ between the isometric reference contractions and any of the force-enhanced or force-depressed conditions. Therefore, we rejected our hypothesis and concluded that differences in fiber lengths or angles of pennation do not contribute to the observed force enhancement/depression in human tibialis anterior, and speculate that this result is likely true for other muscles too.