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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. [ABSTRACT FROM AUTHOR]

This study examined the relationship between body segment mass and running performance in endurance runners. The total (muscle, fat, and bone masses), lean (muscle mass), and fat masses of the leg, arm, and trunk segments in 37 well-trained endurance runners were measured using dual-energy X-ray absorptiometer. The relative segment mass was calculated by normalizing the absolute mass to body mass. There were no significant correlations between absolute total, lean, and fat masses of all 3 segments and personal best 5000-m race time. No significant correlations were also observed between all 3 relative masses of the arm segment and personal best 5000-m race time. In contrast, medium positive correlations were observed between the relative total and lean masses of the leg segment and personal best 5000-m race time (r =.387 and.335, respectively, both P ≤.031). Furthermore, large negative correlations were observed between the relative total and lean masses of the trunk segment and personal best 5000-m race time (r = −.500 and −.548, respectively, both P ≤.002). These findings suggest that a mass distribution with smaller leg mass and greater trunk mass may be advantageous for achieving better running performance in endurance runners. [ABSTRACT FROM AUTHOR]

Context: Static postural control deficits are commonly documented among individuals with chronic ankle instability (CAI). Evidence suggests individuals with CAI who seek medical attention after an ankle sprain report fewer subjective symptoms. It is unknown if seeking medical attention and receiving supervised physical rehabilitation has a similar effect on objective outcomes, such as static postural control. Objective: To compare measures of single-limb postural control and center of pressure (COP) location between participants with CAI who did or did not self-report attending supervised rehabilitation at the time of their first lateral ankle sprain. Design: Retrospective cohort. Setting: Laboratory. Patients (or Other Participants): Twenty-nine participants with CAI who did (n = 14) or did not (n = 15) self-report attending supervised rehabilitation. Intervention(s): Self-reported attendance or not of supervised rehabilitation at the time of initial injury. Main Outcome Measures: Participants performed three 20-second trials of single-limb stance on a force plate with eyes open. Main outcome measures included the COP velocities, time-to-boundary (TTB) absolute minima, mean of TTB minima, and SD of TTB minima in the anteroposterior and mediolateral directions. The spatial distribution of the COP data points under the foot was quantified within 4 equally proportional sections labeled anteromedial, anterolateral, posteromedial, and posterolateral. Results: Participants who reported attending supervised rehabilitation after their initial ankle sprain had a lower COP velocity in the anterior–posterior direction (P =.030), and higher TTB anterior–posterior absolute minimum (P =.033) and mean minima (P =.050) compared with those who did not attend supervised rehabilitation. Conclusions: Among individuals with CAI, not attending supervised rehabilitation at the time of initial injury may lead to worse static postural control outcomes. Clinicians should continue advocating for patients recovering from an acute ankle sprain to seek medical attention and provide continued care in the form of physical rehabilitation. [ABSTRACT FROM AUTHOR]

This study aimed to examine differences in the intestinal microbiota diversity in individuals with and without a history of a lateral ankle sprain (LAS). Fifty male college student athletes with (n=32) and without (n=18) a LAS history participated in this study. Faecal samples were collected in the morning after awakening during an off-season, and faecal microbiota were characterized via bacteria 16S rRNA amplicon sequencing. Alpha-diversity metrics and ß-diversity indices were calculated to assess the gut microbiota diversity. The LAS-history group significantly had lower Chao1 (p=0.020) and abundance-based coverage estimators (p=0.035) indices compared to the control group. Gut microbiota composition was not significantly different between athletes with a LAS history and controls (R2 =0.01, p 0.414). Athletes with a history of LASs had significantly higher proportions of Bacteroides Fragilis (p=0.024) and Ruminococcus Gnavus (p=0.021) compared with controls. The gut microbiota of athletes with a LAS history had less richness compared to controls, indicating potential associations between a LAS and the gut microbiota. This study highlights the potential link of a LAS to global health. This study may help raise awareness of strategies to prevent long-term health-related negative consequences in people suffering from LASs. [ABSTRACT FROM AUTHOR]

This study examined the relationship between Achilles tendon (AT) length and 100-m sprint time in sprinters. The AT lengths at 3 different portions of the triceps surae muscle in 48 well-trained sprinters were measured using magnetic resonance imaging. The 3 AT lengths were calculated as the distance from the calcaneal tuberosity to the muscle–tendon junction of the soleus, gastrocnemius medialis, and gastrocnemius lateralis, respectively. The absolute 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = −.023 to.064, all Ps >.05). Furthermore, to minimize the differences in the leg length among participants, the 3 AT lengths were normalized to the shank length, and the relative 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r =.023 to.102, all Ps >.05). Additionally, no significant correlations were observed between the absolute and relative (normalized to body mass) cross-sectional areas of the AT and personal best 100-m sprint time (r =.012 and.084, respectively, both Ps >.05). These findings suggest that the AT morphological variables, including the length, may not be related to superior 100-m sprint time in sprinters. [ABSTRACT FROM AUTHOR]

This study aimed to compare time-to-boundary and sample entropy during a single-leg balance task between individuals with chronic ankle instability (CAI), lateral ankle sprain copers, and healthy controls. Twenty-two participants with CAI, 20 lateral ankle sprain copers, and 24 healthy controls performed a single-leg balance task during an eyes-closed condition. Participants with CAI exhibited lower time-to-boundary values compared with lateral ankle sprain copers and healthy controls. However, we did not find differences in sample entropy variables between cohorts. A decrease in time-to-boundary values in participants with CAI indicated that CAI may constrain the ability of the sensorimotor system to maintain the center of pressure within the boundaries of the base of support. However, the regularity of the center of pressure velocity time series appears not to be altered in the CAI cohort in this study. [ABSTRACT FROM AUTHOR]