Impact of specialized fatigue and backhand smash on the ankle biomechanics of female badminton players.

During fatigued conditions, badminton players may experience adverse effects on their ankle joints during smash landings. In addition, the risk of ankle injury may vary with different landing strategies. This study aimed to investigate the influence of sport-specific fatigue factors and two backhand smash actions on ankle biomechanical indices. Thirteen female badminton players (age: 21.2 ± 1.9 years; height: 167.1 ± 4.1 cm; weight: 57.3 ± 5.1 kg; BMI: 20.54 ± 1.57 kg/m2) participated in this study. An 8-camera Vicon motion capture system and three Kistler force platforms were used to collect kinematic and kinetic data before and after fatigue for backhand rear-court jump smash (BRJS) and backhand lateral jump smash (BLJS). A 2 × 2 repeated measures analysis of variance was employed to analyze the effects of these smash landing actions and fatigue factors on ankle biomechanical parameters. Fatigue significantly affected the ankle-joint plantarflexion and inversion angles at the initial contact (IC) phase (p < 0.05), with both angles increasing substantially post-fatigue. From a kinetic perspective, fatigue considerably influenced the peak plantarflexion and peak inversion moments at the ankle joint, which resulted in a decrease the former and an increase in the latter after fatigue. The two smash landing actions demonstrated different landing strategies, and significant main effects were observed on the ankle plantarflexion angle, inversion angle, peak dorsiflexion/plantarflexion moment, peak inversion/eversion moment, and peak internal rotation moment (p < 0.05). The BLJS landing had a much greater landing inversion angle, peak inversion moment, and peak internal rotation moment compared with BRJS landing. The interaction effects of fatigue and smash actions significantly affected the muscle force of the peroneus longus (PL), with a more pronounced decrease in the force of the PL muscle post-fatigue in the BLJS action(post-hoc < 0.05). This study demonstrated that fatigue and smash actions, specifically BRJS and BLJS, significantly affect ankle biomechanical parameters. After fatigue, both actions showed a notable increase in IC plantarflexion and inversion angles and peak inversion moments, which may elevate the risk of lateral ankle sprains. Compared with BRJS, BLJS poses a higher risk of lateral ankle sprains after fatigue.

Bilateral Os Trigonum Fracture Treated With Simultaneous Posterior Ankle Arthroscopy.

This is a case report of a 21-year-old female undergraduate student who sustained bilateral ankle injuries while jumping from a moving van wearing 3-inch high heel shoes. Upon initial presentation, her injury was treated conservatively as an acute bilateral ankle sprain for 6 weeks. However, the patient reported no improvement of pain and remained unable to self-ambulate. Bilateral MRI and CT scans of both ankles demonstrated bilateral os trigonum fractures. She underwent bilateral posterior ankle arthroscopic débridement of both os trigonum. At the postoperative 36-month follow-up, the patient reported notable improvement of all functional outcomes (36-item Short Form survey and Foot and Ankle Ability Measure), reported return to the same level of sports activities, and experienced no pain (visual analog scale) on either ankle. This is the first report in the literature of bilateral os trigonum fracture treated with simultaneous posterior ankle arthroscopic débridement.

Long-term outcome of flexor hallucis longus tendon transfer for chronic Achilles tendon rupture with large defect: A retrospective series.

There are multiple surgical options for treatment of chronic Achilles tendon (AT) rupture according to the classifications and length of defect. However, no gold standard method has been confirmed, and there is no clear evidence to support the superiority of 1 procedure over others. This study aimed to evaluate the long-term clinical outcome of flexor hallucis longus tendon (FHL) transfer for chronic AT rupture with large defect. Clinical data of patients treated with FHL transfer due to chronic AT rupture between January 2009 and October 2019 were reviewed retrospectively. All cases were presented with AT rupture for more than 4 weeks after injury. The gap between ruptured ends was > 5 cm after debridement in all patients. The harvest of FHL was performed through a single incision in accordance with AT rupture debridement in all cases. Clinical outcomes were assessed with AOFAS ankle-hindfoot scale, Achilles tendon total rupture score and AOFAS hallux metatarsophalangeal-interphalangeal scale. Twenty-eight patients were followed successfully for 62.6 ±â€…22.2 months. According to the complete datasets obtained from 28 patients, none of the tendons re-ruptured. The AOFAS ankle-hindfoot scale and Achilles tendon total rupture score at last follow-up visit was 90.4 ±â€…5.7 and 89.8 ±â€…5.3 respectively, which revealed statistically significant improvement from the preoperative score of 61.1 ±â€…6.7 and 53.8 ±â€…8.3. The AOFAS hallux metatarsophalangeal-interphalangeal scale at last follow-up visit was 87.5 ±â€…6.1. The FHL transfer through a single incision for chronic AT rupture with large defect is a safe and simple method with low risk of morbidity and complications.

Rotational ankle instability: A current concept review.

Ankle sprains are extremely common. It is important to have a clear insight of the course of recovery after such injury to evaluate the effective strategies to guide management decisions, and understand the potential risk factors involved in the development of chronic problems and recurrent ankle sprains. When a prompt diagnosis is not formulated, ligament tears can remain untreated, and chronic ankle instability can result after acute lateral or medial ankle sprain. When the medial ligament complex (MLC), in particular the anterior fascicle of the deltoid ligament, is involved, rotational ankle instability (RAI) can develop. Generally, a tear of the anterior fibres of the MCL accompanied by anterior talofibular ligament (ATFL) insufficiency has been associated with RAI, while injury of the intermediate fibres of the MLC has been associated with medial ankle instability (MAI). Conservative management is the first line of treatment, with surgery reserved for special cases or if rehabilitation has failed. Regarding surgery, several options are available, including anatomic repair, anatomic reconstruction, and tenodesis procedures. Ankle arthroscopy is increasingly used to address ligament insufficiency and to identify and treat intra-articular pathologies. Repair of MLC tears by an arthroscopic all-inside procedure is effective in both MAI and RAI.

Ankle sprain and podoscopic footprint pattern in female volleyball players.

Ankle sprain (AS) is the most common sports injury that can be complicated by chronic joint instability. The aim of this study was to examine the relationship between foot types and the ankle sprain events suffered during the sport career in female volleyball players. In this retrospective study, we randomly selected 98 female volleyball players competing in several divisions. Data were obtained from self-administered questionnaires in which the athlete noted data about volleyball practice, whether they had had ankle sprains and the number of these events. Plantar footprint was photographed by a plantoscope classifying each foot as normal, flat or cavus (196 feet). Of the 196 feet, 145 (74.0%) were normal, 8 (4.1%) were flat 43 and (21.9%) were cavus. Thirthy-five athletes reported at least one AS during volleyball practice. In total 65 sprain injuries were reported (35 to the right side and 30 to the left side). In 22 ankles (14 right, 8 left) sprain reinjure (AS >1) have been reported. A higher AS reinjury rate is correlated to the cavus footprint pattern (p = 0,005). Cavus foot associates to a higher risk of reinjury for ankle sprains in female volleyball players. Knowing the athletes which are more likely to sustain a reinjure may be helpful for the orthopedic surgeon to plan preventive strategies.

The Burden of the "Simple Ankle Sprains": A Review of the Epidemiology and Long-Term Impact.

Lateral ankle sprain (LAS) is not as simple as it was believed to be as it has substantial negative impacts on the active sporting population. The negative impact on physical function, quality of life (QoL) and economic burden is significant with increased risk of reinjury, development of chronic lateral ankle instability and posttraumatic ankle osteoarthritis resulting in functional deficits, decreased QoL and chronic disabilities. Economic burden from a societal perspective demonstrated notably higher indirect costs from productivity loss. Preventative interventions with early surgery for a selective cohort of active sporting population may be considered to mitigate morbidities associated with LAS.

Acute Ankle Sprain in Elite Athletes: How to Get Them Back to the Game?

Despite the high frequency of ankle sprains, the ideal management is controversial, and a significant percentage of patients sustaining an ankle sprain never fully recover. There is strong evidence that residual disability of ankle joint injury is often caused by an inadequate rehabilitation and training program and early return to sports. Therefore, the athlete should start their criteria-based rehabilitation and gradually progress through the programmed activities, including cryotherapy, edema relief, optimal weight-bearing management, range of motion exercises for ankle dorsiflexion improvement, triceps surae stretching, isometric exercises and peroneus muscles strengthening, balance and proprioception training, and bracing/taping.

Epidemiology of Lateral Ligament Complex Tears of the Ankle in National Collegiate Athletic Association (NCAA) Sports: 2014-15 Through 2018-19.

BACKGROUND: Epidemiological studies of lateral ankle sprains in NCAA sports are important in appraising the burden of this injury and informing prevention efforts. PURPOSE: To describe the epidemiology of lateral ankle sprains in NCAA sports during the 2014-15 through 2018-19 seasons. STUDY DESIGN: Descriptive epidemiology study. METHODS: Injury and exposure information collected within the NCAA Injury Surveillance Program (ISP) were examined. Counts, rates, and proportions of lateral ankle sprains were used to describe injury incidence by sport, event type (practices, competitions), season segment (preseason, regular season, postseason), injury mechanism (player contact, noncontact, and surface contact, injury history (new, recurrent), and time loss (time loss [≥1 day], non-time loss). Injury rate ratios (IRRs) were used to examine differential injury rates, and injury proportion ratios (IPRs) were used to examine differential distributions. RESULTS: A total of 3910 lateral ankle sprains were reported (4.61 per 10,000 athlete exposures) during the study period, and the overall rate was highest in men's basketball (11.82 per 10,000 athlete exposures). The competition-related injury rate was higher than the practice-related rate (IRR, 3.24; 95% CI, 3.04-3.45), and across season segments, the overall rate was highest in preseason (4.99 per 10,000 athlete exposures). Lateral ankle sprains were most often attributed to player-contact mechanisms in men's (43.2%) and women's sports (35.1%), although injuries were more prevalently attributed to player contact in men's than in women's sports (IPR, 1.23; 95% CI, 1.13-1.34). Overall, 49.7% of all lateral ankle sprains were time loss injuries. CONCLUSIONS: The findings of this study are consistent with previous epidemiological investigations of lateral ankle sprains among NCAA athletes. Results offer additional context on differential injury mechanisms between men's and women's sports and on injury risk across the competitive season. Future research may examine the effectiveness of deploying injury prevention programs before the start of a season.

Lower Extremity Injury Rates on Artificial Turf Versus Natural Grass Playing Surfaces: A Systematic Review.

BACKGROUND: No study has provided a comprehensive systematic review of sports injuries on artificial turf versus natural grass. PURPOSE: To comprehensively examine the risk of overall injuries and multiple types of lower extremity injuries across all sports, all levels of competition, and on both old-generation and new-generation artificial turf. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: A systematic review of the English-language literature was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All included articles compared overall injury rates or lower extremity (hip, knee, or foot and ankle) injury rates on artificial turf and natural grass. All sports, levels of competition, and turf types were included. Studies were excluded if they did not include overall injury rates or lower extremity injury rates. Because of the heterogeneity of the included studies, no attempt was made to aggregate risk ratios to conduct a quantitative meta-analysis. RESULTS: A total of 53 articles published between 1972 and 2020 were identified for study inclusion. Most studies on new-generation turf (13/18 articles) found similar overall injury rates between playing surfaces. When individual anatomic injury locations were analyzed, the greatest proportion of articles reported a higher foot and ankle injury rate on artificial turf compared with natural grass, both with old-generation (3/4 articles) and new-generation (9/19 articles) turf. Similar knee and hip injury rates were reported between playing surfaces for soccer athletes on new-generation turf, but football players, particularly those at high levels of competition, were more likely to sustain a knee injury on artificial turf than on natural grass. CONCLUSION: The available body of literature suggests a higher rate of foot and ankle injuries on artificial turf, both old-generation and new-generation turf, compared with natural grass. High-quality studies also suggest that the rates of knee injuries and hip injuries are similar between playing surfaces, although elite-level football athletes may be more predisposed to knee injuries on artificial turf compared with natural grass. Only a few articles in the literature reported a higher overall injury rate on natural grass compared with artificial turf, and all of these studies received financial support from the artificial turf industry.

Risk factors for acute ankle sprains in field-based, team contact sports: a systematic review of prospective etiological studies.

OBJECTIVE: The aim of this systematic review was to identify prospectively measured ankle sprain risk factors in field-based team contact sports. METHODS: Eight databases including SPORTDiscus, CINAHL Complete, MEDLINE (EBSCO), Education Source, Web of Science, Scopus, Embase, and Pubmed were searched using specific Boolean terms. A modified-CASP diagnostic test assessed the quality of the included studies. Extensive data extraction included but was not limited to injury definition, protocols for injury diagnosis and recording, and outcomes associated with ankle sprain. RESULTS: 4012 records were returned from the online search and 17 studies met the inclusion criteria for this review. Twelve different risk factors including anatomic alignment of the foot and ankle, joint laxity, height, mass, BMI (body mass index), age, ankle strength, hip strength, single leg landing performance (ground reaction force, pelvic internal rotation, and knee varus), and single leg reach were all found to be associated with ankle sprain incidence. Injury definitions and methods of diagnosis and recording varied across the 17 studies. CONCLUSION: This review updates the literature on prospective risk factors for ankle sprain in a specific population rather than heterogeneous cohorts previously studied. From more than 20 categories of risk factors investigated for ankle sprain association across 17 studies in field-based team contact sports, 12 variables were found to be associated with increased incidence of ankle sprain. In order to reduce the risk of ankle sprain, BMI, ankle plantar and dorsiflexion strength, hip strength, and single leg landing performance should be factored in to athlete assessment and subsequent program design. More studies utilizing standardized definitions and methods of recording and reporting are needed. Future prospective etiological studies will allow strength and conditioning coaches, physiotherapists, and physicians to apply specific training principles to reduce the risk and occurrence of ankle sprain injuries.

Dance-Related Foot and Ankle Injuries and Pathologies.

Dancers are highly vulnerable to injuries due to high dynamic overload, extreme positions and motions, and excessive use. Increased load at the forefoot with jumping and high-impact lands can cause sesamoiditis and stress fractures of the metatarsals. Significant plantarflexion can lead to posterior joint impingement and flexor hallucis longus tendonitis, whereas forced dorsiflexion can cause anterior joint impingement. Most pathologies can be diagnosed on physical examination and various imaging modalities. Treatment should be tailored to the dancers' needs and should begin with a course of conservative therapy with immobilization, physical therapy, and activity cessation.

Risk factor of postoperative incision infection after plate internal fixation of calcaneal fractures: a retrospective study.

BACKGROUND: This study aimed to investigate the risk factors for incision infection after plate internal fixation for calcaneal fractures by a traditional lateral L-shaped approach. METHODS: The clinical data of 302 patients with calcaneal fractures who underwent surgical treatment in our hospital from January 2012 to June 2018 were retrospectively analysed, consisting of 177 males and 125 females. The enrolled patients were aged 21 to 75 years, with a mean age of 47.72 years. According to the Sanders classification, 108 patients were type II, 138 patients were type III, and 56 cases were type IV. A univariate analysis was conducted with sex, age, smoking history, history of diabetes, cause of injury, Sanders type, tension blisters, time from injury to surgery, preoperative haemoglobin, preoperative albumin, operation time, and bone grafting as possible risk factors. The factors with statistically significant differences were selected for multivariate binary logistic regression analysis. The clinical cut-off values of these risk factors were calculated using characteristic curves. RESULTS: The follow-up lasted for at least 1 year for all patients, with a mean follow-up time of 15.8 months. The results demonstrated 7.9% (24/302) infection rate after plate internal fixation of calcaneal fractures by the traditional lateral L-shaped approach. Univariate analysis showed that a history of diabetes, preoperative albumin, preoperative haemoglobin, time from injury to surgery, and operation time were correlated with incision infection (p < 0.05). Additionally, multivariate regression analysis indicated that a shorter time from injury to surgery (OR = 1.475, 95% CI: 1.024-2.125, p = 0.037), lower preoperative albumin (OR = 1.559, 95% CI: 1.191-2.041, p = 0.001), and longer operation time (OR = 1.511, 95% CI: 1.219-1.874, p < 0.001) were risk factors for postoperative incision infection, and their cut-off values were 10.5 days, 38.5 g/L, and 84.5 minutes, respectively. CONCLUSION: Longer preoperative stay and operation time were two risk factors for postoperative incision infection. However, lower preoperative albumin level is the highest risk factor in this study. TRIAL REGISTRATION: The trial was registered in the China Clinical Trial Registry (ChiCTR2100047038).

Qualitative Analysis of Risk Factors and Foot and Ankle Injuries in Ballet Dancers.

BACKGROUND: Ballet dancers are exposed to high rates of foot and ankle injury. Nevertheless, there have been limited efforts to capture their perspectives regarding risk of injury, treatment compliance, and prevention. The purpose of this study was to portray the perspectives of ballet dancers collected through organized focus group discussions. METHODS: Seven focus group sessions were conducted, with 47 ballet dancers participating. The conversation was directed to consider a variety of factors related to injury, both direct and remote. Transcripts from these focus groups were coded into ten major themes: internal pressure, external pressure, ballet milestones, seeking treatment, treatment compliance, targeted treatment, return to dance, nondance activities, physical fatigue, and activity preparation. RESULTS: It was found that participants returned to dancing prematurely after injury, faced significant internal and external pressure, lacked adherence to suggested treatment, and identified provider communication as lacking. CONCLUSIONS: The results of this study can help with efforts to reduce injuries, encourage treatment compliance, and improve injury prevention. Future studies might consider the effectiveness of specific interventional approaches.

Treatment of displaced intra-articular calcaneal fractures: A single-center experience study with 20 years follow-up.

INTRODUCTION: This study was conducted to identify the patient characteristics, classification, treatment, complications, and functional outcomes of operatively treated displaced intra-articular calcaneal fractures (DIACFs) in a level-I trauma center over a 20-year period. METHODS: Patients with a DIACF classified as Sanders ≥2 and operatively treated with percutaneous reduction and screw fixation (PSF) or open reduction and internal fixation (ORIF) between 1998 and 2017 were identified. Pre- and postoperative radiological assessments were performed. Functional outcomes were evaluated using the American Orthopaedic Foot & Ankle Society (AOFAS) score and the Maryland Foot Score (MFS). General health and patient satisfaction were assessed using the Short Form-36 Health Survey (SF-36) and the visual analog scale (VAS). RESULTS: In total, 120 patients with a DIACF that were operatively treated with PSF or ORIF. Of these patients, 72 with a total of 80 DIACFs completed the questionnaires (60%). The average follow-up was 130 months. Mean scores for PSF and ORIF were 74 and 75 for AOFAS, 78 and 78 for MFS, 68 and 61 for SF-36, and 7.7 and 7.5 for VAS, respectively. An infection was the most common complication associated with ORIF (31%), and hardware removal (58%) was the most common complication in patients treated with PSF. Overall, 36 patients (68%) were able to return to work after a median time 6 months (IQR, 3-7) and 6 months (IQR, 3,25-6,75) for PSF and ORIF treated, respectively CONCLUSION: This long-term follow-up study reviews ORIF using ELA and PSF in the treatment of DIACFs. This study shows that both treatments are capable of restoring the Böhler angle and yield relatively good long-term functional outcomes. Differences in complication rates were apparent, infectious problems are inherent to ORIF using ELA, and hardware removal is associated with PSF.

Open ankle fractures: Factors influencing unplanned reoperation.

INTRODUCTION: Ankle fractures are amongst the most common open fracture injuries presenting to major trauma centres (MTC) and their management remains a topic of debate. Incidence is increasing particularly in the elderly population however the optimal surgical approach and risk factors for unplanned reoperation remain scarce. We therefore conducted a retrospective case study to analyse our institution's outcomes as well as identify risk factors for early unplanned reoperation. MATERIALS AND METHODS: Sixty-five consecutive open ankle fractures were identified using our institutional database between July 2016 and July 2020. Medical records and operation notes were reviewed to identify patient age at injury, Sex, co-morbidities and other co-morbidities, fracture configuration, extent of soft tissue injury, fixation type and post-operative complications. The data was categorised into four groups for analysis, 1) age, 2) AO-OTA classification 3) Sex 4) Gustilo-Anderson grade. Statistical analysis was undertaken to identify predictors of unplanned reoperation. RESULTS: The mean age of patients at the time of injury was 60.8. Unplanned reoperation rate was 17.5%. Age and Gustilo-Anderson classification grade were both statistically significant predictors of unplanned reoperation. AO-OTA classification, Sex and Diabetes were not statistically significant factors associated with unplanned reoperation. CONCLUSION: Age and quality of soft tissue envelope are significant risk factors for unplanned reoperation. Patients with these risk factors may benefit from an alternative surgical approach.

Surgeon case volume and the risk of complications following surgeries of displaced intra-articular calcaneal fracture.

PURPOSE: This study aimed to address the relationship between surgeon volume and the risk of complications following surgeries of displaced intra-articular calcaneal fractures (DIACFs). METHODS: We retrospectively reviewed the medical records and the follow-up registers for patients who underwent open reduction and internal fixation with plate/screws in our center between January 2015 and June 2020. Surgeon volume was defined as the number of surgically treated calcaneal fractures within the past 12 months, and was dichotomized on basis of the optimal cut-off value. The outcome measure was the documented overall complications within 1 year after surgery. Four logistics regression models were constructed to examine the potential relationship between surgeon volume and complications. RESULTS: Among 585 patients, 49 had documented complications, representing an overall rate of 8.4%. The overall complication rate was 20.0% (22/111) in patients operated on by the low-volume surgeons and 5.7% (27/474) by the high-volume surgeons, with a significant difference (p < 0.001). The 4 multivariate analyses showed steady and robust inverse volume-complication relationship, with OR ranging from 3.8 to 4.4. The restricted cubic splines adjusted for total covariates showed the non-linear fitting "L-shape" or "reverse J-shape" curve (p = 0.041), and the OR was reduced until 10 cases, beyond which the curve leveled. CONCLUSIONS: Our findings reflected the important role of maintaining necessary operative cases, potentially informing optimized surgical care management.

Sinus Tarsi Approach With Percutaneous Screw Fixation for Intra-Articular Calcaneal Fractures.

The aim of this study was to evaluate the outcomes of surgical treatment of intra-articular calcaneal fractures by using the sinus tarsi approach combined with percutaneous medial reduction by leverage technique and percutaneous screw fixation. We assessed the outcomes of 29 patients treated using sinus tarsi approach with percutaneous screw fixation. All patients were evaluated both clinically and radiologically. The Böhler and Gissane angle were evaluated postoperatively using radiographs. During the median follow-up period of 27.0 ± 10.3 months, no cases with failure to reduce or displace hardware were detected. All cases achieved the restoration of a normal Böhler and Gissane angle. The median preoperative Böhler angle was 12.3° ± 2.5° while postoperatively it was 30.5° ± 5.7° (p < .01). The median preoperative Gissane angle was 98.1° ± 7.5°, which was 125.9° ± 3.6° postoperatively (p < .01). At the last follow-up, the median American Orthopedic Foot and Ankle Society hindfoot score was 87.7 ± 5.9, and the median Maryland foot score was 88.6 ± 5.9. Our technique for intra-articular calcaneal fractures can effectively correct calcaneal tuberosity outward displacement, medial wall overlapping, and the hindfoot varus deformity with less soft tissue damage. This technique is a good alternative for the treatment of calcaneal fractures, resulting in minimal soft tissue damage, few wound complications, and excellent radiological and clinical outcomes.

Quadriceps strength asymmetry as predictor of ankle sprain in male volleyball players.

BACKGROUND: Ankle sprain is the most common acute time-loss injury in volleyball and occurs mainly during landing from a jump. Therefore, we have evaluated the role of quadriceps strength and countermovement jump height on ankle sprain occurrence, as these intrinsic modifiable risk factors were not yet evaluated. We have also hypothesized that presence of quadriceps strength asymmetry could be a possible risk factor for ankle sprains in male volleyball players. METHODS: This was a prospective cohort study. Male volleyball players (N.=99) from Slovenian national league participated in the study. Before the start of the season, all participants completed a preseason questionnaire and underwent evaluation of vertical jump performance and bilateral isokinetic strength of the quadriceps (Q) and hamstrings (H). During the subsequent season the players reported acute time loss injuries because of ankle sprain through a weekly questionnaire. RESULTS: We have registered 19 ankle sprains during the season. Overall ankle sprain incidence was 0.41±0.24 per 1000 h. Previous ankle sprain (Odds Ratio: 0.86; 95% CI: 0.25-2.89, P=0.802) and jump height (1.05; 95% CI: 0.94-1.19, P=0.393) were not significant risk factors, while Q strength asymmetry was a significant predictor of an ankle sprain (Odds Ratio: 0.956; 95% CI: 0.919-0.995, P=0.026). Compared with the uninjured players, the injured players had higher right concentric Q strength, higher Q strength asymmetry, and lower concentric right H-Q strength ratio (all P<0.03). CONCLUSIONS: Our results suggest that excessive concentric strength of the right Q, which leads to low H-Q strength ratio, and high bilateral Q strength asymmetry in favor of the right side, could be associated with increased risk of ankle sprains in male volleyball.