The Prevalence and Characteristics of Chronic Ankle Instability in Elite Athletes of Different Sports: A Cross-Sectional Study.

BACKGROUND: Ankle sprains are one of the most common injuries in athletic populations. Misdiagnosed and untreated ankle sprains will cause chronic ankle instability (CAI), which can significantly affect the performance of athletes. This study aimed to investigate the prevalence and characteristics of CAI in elite athletes of different sports. METHOD: This cross-sectional study included 198 elite athletes from Guangdong provincial sports teams. All participants answered a questionnaire about ankle sprains and ankle instability. The severity of their ankle instability was evaluated by the Cumberland Ankle Instability Tool (CAIT). Participants further underwent clinical examinations from sports medicine doctors to determine the presence and characteristics of ankle instability. The datasets were analyzed to determine the differences in prevalence between age, gender, sports teams, and sports categories. RESULTS: In 198 athletes, 39.4% (n = 78) had bilateral CAI while 25.3% (n = 50) had unilateral CAI. Female athletes had a higher prevalence of CAI than male athletes in the study (p = 0.01). Prevalence showed differences between sports categories, and were significantly higher in acrobatic athletes than non-contact athletes (p = 0.03). CONCLUSIONS: CAI was highly prevalent among elite athletes in this study, with female athletes and athletes in acrobatic sports being associated with a higher risk of developing CAI in their professional careers. Therefore, extra precautions need to be taken into account when applying ankle protections for these athletes.

9-(Thio-phen-2-yl)-8,9-dihydro-3H-pyrazolo-[4,3-f]quinolin-7(6H)-one ethanol monosolvate.

In the title compound, C(14)H(11)N(3)OS·C(2)H(5)OH, the dihedral angle between the pyridine N-C(fused)-C(fused)-C(thio-phene) plane and the plane of the thio-phene ring is 81.9 (3)°, indicating that they are close to perpendicular. The dihedral angle between this pyridine plane and the benzene ring is 1.3 (3)°. The thio-phene ring is disordered over two coplanar orientations with an occupancy ratio of 0.692 (7):0.308 (7), while the ethanol solvent mol-ecule is also disordered over two sets of site in a 0.66 (4):0.34 (4) ratio. In the crystal, chains are formed along the b axis by N-H⋯O and O-H⋯N inter-actions with adjacent chains being connected through C-H⋯N and C-H⋯S inter-actions.

5-(4-Chloro-phen-yl)-1-methyl-3-phenyl-3,6,8,9-tetra-hydro-pyrazolo-[3,4-b]thio-pyrano[4,3-d]pyridine.

The title compound, C(22)H(18)ClN(3)S, was synthesized by the reaction of 4-chloro-benzaldehyde, tetra-hydro-thio-pyran-4-one and 3-methyl-1-phenyl-1H-pyrazol-5-amine in acetic acid without a catalyst. The pyridine and pyrazole rings are almost coplanar, the dihedral angle between their mean planes being 2.50 (1)°. The thio-pyran ring exhibits an envelope conformation. The crystal packing is stabilized by inter-molecular C-H⋯Cl hydrogen bonds and by C-H⋯π and π-π inter-actions [centroid-centroid distances of 3.825 (2) Šbetween pyridine rings and 3.557 (2) Šbetween pyrazole and pyridine rings.

14-(1,3-Benzodioxol-5-yl)-7,14-dihydro-dibenzo[a,j]acridine.

The title compound, C(28)H(19)NO(2), was synthesized by the reaction of 1,3-benzodioxole-5-carbaldehyde with naphthalen-2-amine catalyzed by thio-salicylic acid in acetic acid. The central dihydropyridine ring adopts a boat conformation. The two planar (r.m.s. deviations = 0.0158 and 0.0552 Å) bicyclic parts make a dihedral angle of 16.16 (5)° with respect to each other. The crystal packing is stabilized by inter-molecular N-H⋯O hydrogen bonds and C-H⋯π inter-actions.

9,9-Dimethyl-12-(3-nitro-phen-yl)-7,8,9,10,11,12-hexa-hydro-benz[a]acridin-11-one.

The title compound, C(25)H(22)N(2)O(3), was synthesized by the reaction of 3-nitro-benzaldehyde, dimedone and 2-naphthyl-amine in ethanol. In the mol-ecular structure, the cyclo-hexenone ring adopts an envelope conformation, whereas the piperidine ring has a boat conformation. The crystal packing is stabilized by inter-molecular N-H⋯O hydrogen bonds.

2,2,7,7-Tetra-methyl-1,2,3,6,7,8-hexa-hydro-cinnolino[5,4,3-cde]cinnoline.

The asymmetric unit of the title compound, C(16)H(20)N(4), contains two half-mol-ecules, which are completed by crystallographic inversion symmetry. The pyridazine rings are conjugated and the cyclo-hexane rings adopt envelope conformations.

3-(4-Bromo-phen-yl)-3-(4-hydr-oxy-6-oxo-1,6-dihydro-pyrimidin-5-yl)-N-[(S)-1-phenyl-ethyl]propanamide.

In the mol-ecule of the title compound, C(21)H(20)BrN(3)O(3), the pyrimidine ring is oriented at dihedral angles of 80.87 (3) and 15.99 (3)°, respectively, to the pyrimidine and bromo-phenyl rings. The dihedral angle between the two benzene rings is 88.37 (3)°. In the crystal structure, inter-molecular N-H⋯O and O-H⋯N hydrogen bonds link the mol-ecules. A π-π contact between pyrimidine and phenyl rings [centroid-centroid distance = 3.776 (3) Å] may further stabilize the structure. The methine H and the methyl C and H atoms are disordered over two positions and were refined with occupancies of 0.522 (13) and 0.478 (13).

3,6-Dimethyl-1-phenyl-4-(2-thien-yl)-8-(2-thienylmethyl-ene)-5,6,7,8-tetra-hydro-1H-pyrazolo[3,4-b][1,6]naphthyridine.

In the mol-ecule of the title compound, C(26)H(22)N(4)S(2), the pyrazole ring is oriented at a dihedral angle of 0.85 (3)° with respect to the adjacent naphthyridine ring, while the other ring of naphthyridine adopts an envelope conformation. The dihedral angle between phenyl and pyrazole rings is 87.65 (3)°. In the crystal structure, weak inter-molecular C-H⋯N inter-actions link the mol-ecules into chains. The π-π contacts between the naphthyridine rings and the naphthyridine and thio-phene rings [centroid-centroid distances = 3.766 (3) and 3.878 (3) Å] may further stabilize the structure. A weak C-H⋯π inter-action is also present.

7,14-Bis(4-bromo-phen-yl)-2,11,11-trimethyl-1,4,10,12-tetra-oxa-dispiro-[4.2.5.2]penta-decane-9,13-dione.

In the mol-ecule of the title compound, C(26)H(26)Br(2)O(6), the cyclo-hexane ring is in a chair conformation, while the five-membered and 1,3-dioxane rings both adopt envelope conformations. The dihedral angle between the benzene rings is 77.21 (3)°. In the crystal structure, weak inter-molecular C-H⋯O inter-actions link the mol-ecules into centrosymmetric dimers, forming R(2) (2)(14) ring motifs. One of the Br atoms, the methyl C and H atoms, and the C atom bonded to the methyl group of the five-membered ring are disordered over two positions. The Br atoms were refined with occupancies of 0.51 (4) and 0.49 (4), while the C and H atoms were refined with occupancies of 0.320 (18) and 0.680 (18).