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Background: Altered reorganization of the sensorimotor system after an initial lateral ankle sprain may lead to a chronic neuromuscular maladaptation in multiple body locations. Specifically, decreased diaphragm contractility has been observed in patients with chronic ankle instability (CAI). The diaphragm has an essential role in postural control. Decreased diaphragm contractility could associate with diminished postural control commonly observed in patients with CAI. However, no study has determined if diaphragm contractility contributes to postural control in a CAI population.Hypothesis: Decreased diaphragm contractility would be negatively associated with static postural control in patients with CAI.Study Design: Cross-sectional study design.Level of Evidence: Level 4.Methods: A total of 15 participants with CAI participated voluntarily. An ultrasonography assessment was performed to quantify the right and left hemidiaphragm thickness at the end of resting inspiration and expiration in supine while breathing quietly. The degree of diaphragm contractility was calculated from the diaphragm thickness. Participants performed 3 eyes-open trials of a 20-second single-leg balance task on the involved limb. Static postural control measures included the center of pressure velocity (COPV) and mean of time-to-boundary (TTB) minima in the anteroposterior (AP) and mediolateral directions.Results: Moderate correlations of the right hemidiaphragm contractility were observed with COPV (ρ = -0.54) and TTB mean minima (ρ = 0.56) (P< 0.05) in the AP direction. The left hemidiaphragm contractility was moderately correlated with COPV (ρ = −0.56) and TTB mean minima (ρ = 0.60) (P< 0.05) in the AP direction.Conclusion: Lower diaphragm contractility may be associated with diminished static postural control in the AP direction in patients with CAI.Clinical Relevance: This study highlights diaphragm contractility could be a potential connection with diminished static postural control in patients with CAI. Our data raise new avenues for future exploration including potential beneficial effects of implementation of diaphragm breathing exercises and techniques for restoring static postural control in patients with CAI.

Shimozawa, Y, Kurihara, T, Kusagawa, Y, Hori, M, Numasawa, S, Sugiyama, T, Tanaka, T, Suga, T, Terada, RS, Isaka, T, and Terada, M. Point prevalence of the biomechanical dimension of dysfunctional breathing patterns among competitive athletes. J Strength Cond Res37(2): 270–276, 2023—There is growing evidence of associations between altered biomechanical breathing patterns and numerous musculoskeletal and psychological conditions. The prevalence of dysfunctional and diaphragmatic breathing patterns is unknown among athletic populations. The purpose of this study was to examine the prevalence of dysfunctional and diaphragmatic breathing patterns among athletic populations with a clinical measure to assess the biomechanical dimension of breathing patterns. Using a cross-sectional design, 1,933 athletes across multiple sports and ages were screened from 2017 to 2020. Breathing patterns were assessed using the Hi-Lo test in the standing position. Scores of the Hi-Lo test were determined based on the presence or absence of abdominal excursion, anterior–posterior chest expansion, superior rib cage migration, and shoulder elevation. The Hi-Lo test scores were used to categorize observational breathing mechanics as dysfunctional and diaphragmatic breathing patterns. The prevalence of athletes with dysfunctional breathing patterns was 90.6% (1,751 of 1,933). Athletes with diaphragmatic breathing patterns accounted for 9.4% of all athletes in our sample (182 of 1,933). There were no differences in the proportion of breathing patterns between male and female athletes (p= 0.424). Breathing patterns observations were associated with sport-setting categories (p= 0.002). The highest percentages of dysfunctional breathers were in middle school student athletes (93.7%), followed by elementary school student athletes (91.2%), high school student athletes (90.6%), professional/semiprofessional athletes (87.5%), and collegiate athletes (84.8%). The current study observed that dysfunctional breathing patterns (90.6%) in the biomechanical dimension were more prevalent than diaphragmatic breathing pattern (9.4%) among competitive athletes. These results suggest that clinicians may need to consider screening breathing patterns and implementing intervention programs aimed to improve the efficiency of biomechanical dimensions of breathing patterns in athletic populations. This study may help raise awareness of impacts of dysfunctional breathing patterns on athletes' health and performance.

•Associations were found between chronic ankle instability and altered corticospinal excitability and inhibition of the tibialis anterior during single-leg standing.•Individuals with chronic ankle instability may have an increase in sensitivity of inhibitory intermediate neurons and a decrease in sensitivity of excitatory neurons in the corticospinal pathway.•Individuals with chronic ankle instability may encounter more difficulty controlling the tibialis anterior muscle during a single-leg stance.

BackgroundDespite being the most commonly incurred sports injury with a high recurrence rate, there are no guidelines to inform return to sport (RTS) decisions following acute lateral ankle sprain injuries. We aimed to develop a list of assessment items to address this gap.MethodsWe used a three-round Delphi survey approach to develop consensus of opinion among 155 globally diverse health professionals working in elite field or court sports. This involved surveys that were structured in question format with both closed-response and open-response options. We asked panellists to indicate their agreement about whether or not assessment items should support the RTS decision after an acute lateral ankle sprain injury. The second and third round surveys included quantitative and qualitative feedback from the previous round. We defined a priori consensus being reached at >70% agree or disagree responses.ResultsSixteen assessment items reached consensus to be included in the RTS decision after an acute lateral ankle sprain injury. They were mapped to five domains with 98% panellist agreement—PAASS: Pain (during sport participation and over the last 24 hours), Ankle impairments (range of motion; muscle strength, endurance and power), Athlete perception (perceived ankle confidence/reassurance and stability; psychological readiness), Sensorimotor control (proprioception; dynamic postural control/balance), Sport/functional performance (hopping, jumping and agility; sport-specific drills; ability to complete a full training session).ConclusionExpert opinion indicated that pain severity, ankle impairments, sensorimotor control, athlete perception/readiness and sport/functional performance should be assessed to inform the RTS decision following an acute lateral ankle sprain injury.Trial registration numberACTRN12619000522112.

Background: Chronic ankle instability (CAI) is associated with hip strength deficits and altered movement in the lower extremity. However, it remains unclear how hip strength deficits contribute to lateral ankle sprain (LAS) mechanisms. We aimed to compare lower extremity landing kinematics and isometric hip strength between individuals with and without CAI and examine associations between hip kinematics and strength.Methods: Seventy-six individuals completed 5 single-leg landings, during which we collected three-dimensional ankle, knee, and hip kinematics from 200 milliseconds pre–initial contact to 50 milliseconds post–initial contact. We calculated average peak torque (Nm/kg) from 3 trials of isometric hip extension, abduction, and external rotation strength testing. One-way analyses of variance assessed group differences (CAI, LAS coper, and control) in hip strength and kinematics. Pearson product moment correlations assessed associations between hip kinematics and strength. We adjusted the kinematic group comparisons and correlation analyses for multiple comparisons using the Benjamini-Hochberg method.Results: The CAI group exhibited less hip abduction during landing than LAS copers and controls. The CAI group had lower hip external rotation strength than LAS copers (P= .04, d= 0.62 [0.05, 1.17]) and controls (P< .01, d= 0.87 [0.28, 1.43]). Effect sizes suggest that the CAI group had deficits in EXT compared with controls (d= 0.63 [0.06, 1.19]). Hip strength was not associated with hip landing kinematics for any group.Conclusion: Altered landing mechanics displayed by the CAI group may promote mechanisms of LAS, but they are not associated with isometric hip strength. However, hip strength deficits may negatively impact other functional tasks, and they should still be considered during rehabilitation.Level of Evidence: Level III, case-control study.

ObjectiveTo identify which therapeutic intervention may be most effective for improving self-reported function in patients with chronic ankle instability (CAI).DesignSystematic literature review. Articles were appraised using the Downs and Black Checklist by 3 reviewers.Data sourcesPubMed along with CINAHL, MEDLINE and SPORTDiscus within EBSCOhost for pertinent articles from their inception through August 2016.Eligibility criteria for selected studiesArticles included were required to (1) be written in English, (2) report adequate data to calculate effect sizes, (3) identify patients with CAI, (4) use some form of therapeutic intervention and (5) use a self-reported questionnaire as a main outcome measurement.ResultsA broad spectrum of therapeutic interventions were identified related to balance training, multimodal rehabilitation, joint mobilisation, resistive training, soft-tissue mobilisation, passive calf stretching and orthotics. All of the articles included in the balance training category had moderate-to-strong Hedges g with none of the 95% CIs crossing 0. Hedges g effect sizes ranged from −0.67 to −2.31 and −0.51 to −1.43 for activities of daily living and physical activity, respectively. The multimodal rehabilitation category also produced moderate-to-strong Hedges g effect sizes but with large CIs crossing 0. Hedges g effect sizes ranged from −0.47 to −9.29 and −0.62 to −24.29 for activities of daily living and physical activity, respectively.ConclusionsThe main findings from this systematic review were balance training provided the most consistent improvements in self-reported function for patients with CAI.

Context:Neuromuscular and mechanical deficiencies are commonly studied in participants with chronic ankle instability (CAI). Few investigators have attempted to comprehensively consider sensorimotor and mechanical differences among people with CAI, copers who did not present with prolonged dysfunctions after an initial ankle sprain, and a healthy control group.Objective:To determine if differences exist in spinal reflex excitability and ankle laxity among participants with CAI, copers, and healthy controls.Design:Case-control study.Setting:Research laboratory.Patients or Other Participants:Thirty-seven participants with CAI, 30 participants categorized as copers, and 26 healthy control participants.Main Outcome Measure(s):We assessed spinal reflex excitability of the soleus using the Hoffmann reflex protocol. Participants' ankle laxity was measured with an instrumented ankle arthrometer. The maximum Hoffmann reflex : maximal muscle response ratio was calculated. Ankle laxity was measured as the total displacement in the anterior-posterior directions (mm) and total rotation in the inversion and eversion directions (°).Results:Spinal reflex excitability was diminished in participants with CAI compared with copers and control participants (P .01). No differences were observed among any of the groups for ankle laxity.Conclusion:Changes in the spinal reflex excitability of the soleus that likely affect ankle stability were seen only in the CAI group, yet no mechanical differences were noted across the groups. These findings support the importance of finding effective ways to increase spinal reflex excitability for the purpose of treating neural excitability dysfunction in patients with CAI.

Background: As an adjunct to running training, heavy resistance and plyometric training have recently drawn attention as potential training modalities that improve running economy and running time trial performance. However, the comparative effectiveness is unknown. The present systematic review and meta-analysis aimed to determine if there are different effects of heavy resistance training versus plyometric training as an adjunct to running training on running economy and running time trial performance in long-distance runners. Methods: Electronic databases of PubMed, Web of Science, and SPORTDiscus were searched. Twenty-two studies completely satisfied the selection criteria. Data on running economy and running time trial performance were extracted for the meta-analysis. Subgroup analyses were performed with selected potential moderators. Results: The pooled effect size for running economy in heavy resistance training was greater (g= − 0.32 [95% confidence intervals [CIs] − 0.55 to − 0.10]: effect size = small) than that in plyometric training (g= -0.13 [95% CIs − 0.47 to 0.21]: trivial). The effect on running time trial performance was also larger in heavy resistance training (g= − 0.24 [95% CIs − 1.04 to − 0.55]: small) than that in plyometric training (g= − 0.17 [95% CIs − 0.27 to − 0.06]: trivial). Heavy resistance training with nearly maximal loads (≥ 90% of 1 repetition maximum [1RM], g= − 0.31 [95% CIs − 0.61 to − 0.02]: small) provided greater effects than those with lower loads (&lt; 90% 1RM, g= − 0.17 [95% CIs − 1.05 to 0.70]: trivial). Greater effects were evident when training was performed for a longer period in both heavy resistance (10–14 weeks, g= − 0.45 [95% CIs − 0.83 to − 0.08]: small vs. 6–8 weeks, g= − 0.21 [95% CIs − 0.56 to 0.15]: small) and plyometric training (8–10 weeks, g= 0.26 [95% CIs − 0.67 to 0.15]: small vs. 4–6 weeks, g= − 0.06 [95% CIs 0.67 to 0.55]: trivial). Conclusions: Heavy resistance training, especially with nearly maximal loads, may be superior to plyometric training in improving running economy and running time trial performance. In addition, running economy appears to be improved better when training is performed for a longer period in both heavy resistance and plyometric training.

Context:Few authors have assessed neuromuscular knee-stabilization strategies in individuals with chronic ankle instability (CAI) during functional activities.Objective:To investigate the influence of CAI on neuromuscular characteristics around the knee during a stop-jump task.Design:Case-control study.Setting:Research laboratory.Participants or Other Participants:A total of 19 participants with self-reported unilateral CAI and 19 healthy control participants volunteered for this study.Intervention(s):Participants performed double-legged, vertical stop-jump tasks onto a force plate, and we measured muscle activation around the knee of each limb.Main Outcome Measure(s):We calculated the integrated electromyography for the vastus medialis oblique, vastus lateralis, medial hamstrings, and lateral hamstrings muscles during the 100 ms before and after initial foot contacts with the force plate and normalized by the ensemble peak electromyographic value. Knee sagittal-plane kinematics were also analyzed during a stop-jump task.Results:Compared with control participants, the CAI group demonstrated greater prelanding integrated electromyographic activity of the vastus medialis oblique (CAI 52.28 ± 11.25·ms, control 43.90 ± 10.13·ms, t36 2.41, P .021, effect size 0.78, 95 confidence interval 0.11, 1.43) and less knee-flexion angle at the point of initial foot contact (CAI 7.81° ± 8.27°, control 14.09° ± 8.7°, t36 −2.28, P .029, effect size −0.74, 95 confidence interval −1.38, −0.07) and at 100 ms post–initial foot contact (CAI 51.36° ± 5.29°, control 58.66° ± 7.66°, t36 −3.42, P .002, effect size −1.11, 95 confidence interval −1.77, −0.40). No significant results were noted for the other electromyographic measures.Conclusions:We found altered feed-forward patterns of the vastus medialis oblique and altered postlanding knee sagittal-plane kinematics in the CAI group. These observations may provide insight regarding sensorimotor characteristics that may be associated with CAI.

Context:Clinicians perform therapeutic interventions, such as stretching, manual therapy, electrotherapy, ultrasound, and exercises, to increase ankle dorsiflexion. However, authors of previous studies have not determined which intervention or combination of interventions is most effective.Objective:To determine the magnitude of therapeutic intervention effects on and the most effective therapeutic interventions for restoring normal ankle dorsiflexion after ankle sprain.Data Sources:We performed a comprehensive literature search in Web of Science and EBSCO HOST from 1965 to May 29, 2011, with 19 search terms related to ankle sprain, dorsiflexion, and intervention and by cross-referencing pertinent articles.Study Selection:Eligible studies had to be written in English and include the means and standard deviations of both pretreatment and posttreatment in patients with acute, subacute, or chronic ankle sprains. Outcomes of interest included various joint mobilizations, stretching, local vibration, hyperbaric oxygen therapy, electrical stimulation, and mental-relaxation interventions.Data Extraction:We extracted data on dorsiflexion improvements among various therapeutic applications by calculating Cohen d effect sizes with associated 95 confidence intervals (CIs) and evaluated the methodologic quality using the Physiotherapy Evidence Database (PEDro) scale.Data Synthesis:In total, 9 studies (PEDro score 5.22 ± 1.92) met the inclusion criteria. Static-stretching interventions with a home exercise program had the strongest effects on increasing dorsiflexion in patients 2 weeks after acute ankle sprains (Cohen d 1.06; 95 CI 0.12, 2.42). The range of effect sizes for movement with mobilization on ankle dorsiflexion among individuals with recurrent ankle sprains was small (Cohen d range 0.14 to 0.39).Conclusions:Static-stretching intervention as a part of standardized care yielded the strongest effects on dorsiflexion after acute ankle sprains. The existing evidence suggests that clinicians need to consider what may be the limiting factor of ankle dorsiflexion to select the most appropriate treatments and interventions. Investigators should examine the relationship between improvements in dorsiflexion and patient progress using measures of patient self-reported functional outcome after therapeutic interventions to determine the most appropriate forms of therapeutic interventions to address ankle-dorsiflexion limitation.

The Phebus FPT1 test at IRSN, selected to be ISP-46, has been analyzed by the IMPACT/SAMPSON code, a detailed severe accidents (SAs) analysis code for an LWR. The results for the Bundle phase, involving an examination of bundle degradation and fission products release during SA conditions, were reported. Conclusions obtained from the analyses are as follows: (1) Temperature changes of fuel, cladding, and control rod were well predicted until about 12,000 s when almost all thermocouples measuring them failed. (2) Accumulated hydrogen generation due to Zr/steam reaction differed only about 3% from the test result. (3) Overall, good agreement was obtained for the fuel relocation and an accumulation of debris just below original spacer position was well predicted in the analysis. (4) Analysis of enhanced diffusion due to degraded fuel by Lewis et al.'s method enabled simulation of release behaviors of Xe, Cs, I, and Te within the uncertainties in the test when the effective surface to volume ratio was changed in the evaluation of the UO2 oxidation. (5) Diffusion analysis through single-crystal grain could trace the release behavior of Mo, Sb, Tc, Ru, and Ba observed in the Phebus FPT1 test after optimizing their diffusion coefficients with the effective surface to volume ratio determined above.