This review aimed to investigate characteristics of muscle activation and ground reaction force (GRF) patterns in patients with ankle instability (AI). Relevant studies were sourced from PubMed, CINAHL, SPORTDiscus, and Web of Science through December 2019 for case-control study in any laboratory setting. Inclusion criteria for study selection were (1) subjects with chronic, functional, or mechanical instability or recurrent ankle sprains; (2) primary outcomes consisted of muscle activation of the lower extremity and GRF during landing; and (3) peer-reviewed articles with full text available, including mean, standard deviation, and sample size, to enable data reanalysis. We evaluated four variables related to landing task: (1) muscle activation of the lower extremity before landing, (2) muscle activation of the lower extremity during landing, (3) magnitude of GRF, and (4) time to peak GRF. The effect size using standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated for these variables to make comparisons across studies. Patients with AI had a lower activation of peroneal muscles before landing (SMD = -0.63, p < 0.001, CI = -0.95 to -0.31), greater peak vertical GRF (SMD = 0.21, p = 0.03, CI = 0.01 to 0.40), and shorter time to peak vertical GRF (SMD = -0.51, p < 0.001, CI = -0.72 to -0.29) than those of normal subjects during landing. There was no significant difference in other muscle activation and GRF components between the patients with AI and normal subjects (p > 0.05). Altered muscle activation and GRF before and during landing in AI cases may contribute to both recurrent ankle and ACL injuries and degenerative change of articular.

Taekwondo has been reported to be one of the most injurious sports in the summer Olympics, however, there is a dearth of data about injury profiles for junior athletes. Therefore, we aimed to identify the incidence and profiles of the injuries and illnesses that occurred during the 2018 World Taekwondo Junior Championships and recorded using an online system. Among the 889 athletes, 67 injuries and four illnesses were reported, corresponding to an overall clinical incidence of 7.5 injuries (95% confidence interval [CI]: 5.7–9.3) and 0.5 illnesses (0.1–0.9) per 100 athletes. The most frequent injuries were lower extremity injuries (n = 33, 3.71% of all athletes), mostly in the foot/toe (n = 11, 1.2% of athletes), followed by head and trunk injuries, mostly in the face (n = 14, 1.6% of athletes), and upper extremity injuries, mostly in the fingers (n = 6, 0.7% of athlete). Contusions (n = 37, 4.2% of athlete) were the most frequent injury type, followed by ligament ruptures/sprains and laceration. The most common injury mechanism was contact during an opponent attack (n = 51, 5.7% of athlete). Three mild concussions none resulted in time loss (none required hospital transfer or had prolonged recovery). The respiratory system was the most affected by illness, with pain and fever as symptoms. Environmental factors were the most common cause of illness. This study shows that 7.5 per 100 athletes (38.5/1000 athlete-exposures and 6.9/1000 min-exposures) had new or recurrent injuries, whereas 0.5 per 100 athletes experienced illness. In conclusion, the data shows male athletes reported more injuries than females and the most common cause of injury was due to contact between athletes. Contusions, ligament rupture/sprains, laceration and fractures to the lower extremities, head, and trunk were the most common injury. Knowing these injury profiles of junior taekwondo athletes can help taekwondo stakeholders, especially medical staff to prepare accordingly to ensure the safety of the athletes.

Sports-related traumatic brain injuries are the most common injury in adolescents and young adults due to recurrent concussion experiences and head shock. Therefore, this study was designed to describe player characteristics and situational factors associated with concussions in the World Taekwondo Championships using systematic video analysis. Athlete injury data were collected using a web-based injury surveillance system at the World Taekwondo Championships organized by World Taekwondo from 2017 to 2019. Seven video footage were independently analyzed by four analysts using a modified Heads-Up Checklist. Descriptive statistical analysis was used. The incidence of concussion was 3.21 per 1000 games. Most players with concussions were shorter than their opponents, and most concussions were caused by a roundhouse kick on the front of the face. Regarding the acceleration direction of the head after the impact, transverse and multiplane directions were the most common. Most players with a concussion have used a closed stance and did not use blocking techniques during the defense. The rate of concussions caused by penalties was 42.9%. Based on our findings, no other injury mechanisms, except for direct blows to the head, were observed. Therefore, education on the risk and symptoms of concussion, the appropriate management and blocking techniques should be emphasized in TKD-S to reduce incidence of concussion.

While research exists to induce fatigue using isokinetic dynamometers or simple repetition tasks in patients with chronic ankle instability (CAI), there is a lack of research examining landing movement strategies using fatigue protocols that mimic actual sports. Therefore, we aimed to investigate the effects of CAI and fatiguing exercises on the lower-extremity kinematics and kinetics during single-leg drop landings among patients with CAI, lateral ankle sprain (LAS) copers and controls. A cross-sectional study recruited 20 patients with CAI, 20 LAS copers, and 20 controls in a biomechanics laboratory. All participants performed single-leg drop landings before and after the fatiguing exercises. The fatiguing exercise protocol consisted of a cycle including forward, side, and backward running, L-shape running, side hopping, cone jumps, and tuck jumps. This cycle was repeated until rate of perceived exertion (RPE) reached 17 and heart rate (HR) reached 85% of the maximum. Three-dimensional kinematics and kinetics of the lower extremity were collected and analyzed using functional analysis of variance. All participants reached an RPE level of 17.89 ± 1.02 and HR of 180.64 ± 7.87 (maximal HR 96.11%) at the last cycle of the fatigue protocol. Several group-by-fatigue interactions were noted. Patients with CAI exhibited increased hip external rotation angle and moment, increased angle and decreased moment of knee valgus, and increased hip and knee extension moments after the fatiguing exercise compared with copers and/or controls. Under fatigue conditions, patients with CAI exhibited biomechanical changes in the proximal joint, a stiffer landing position, and biomechanics associated with ankle injuries. Fatigue resistance training should be a key focus during the rehabilitation of these patients to improve their lower-extremity stability.

Context: Medial tibial stress syndrome (MTSS) is a common chronic injury of the lower-extremity in the physically active population. However, the risk factors for MTSS remain unclear. Objective: This study identified the risk factors for MTSS and established the continuum model of lower-extremity alignments, range of motion, muscular strength, and gait kinematics affecting each other and MTSS development. Evidence Acquisition: Online databases including PubMed, CINAHL, SPORTDiscus, and Web of Science were used to retrieve studies related to risk factors for MTSS. The study eligibility criteria were studies that used the MTSS definition of the Yates and White criteria, or included participants with MTSS, except for stress fracture and compartment syndrome. A total of 2099 papers were retrieved during the initial search stage. After screening, based on eligibility criteria and cross-reference, 21 papers were included in this study. Data on lower-extremity alignments, range of motion, muscular strength, and gait biomechanics were extracted as outcome variables for this meta-analysis. Publication bias was assessed using funnel plots and Egger’s regression analysis. Evidence Synthesis: Foot posture index (standardized mean difference [SMD] = 1.23; 95% CI, 0.02–2.43), intercondylar interval (SMD = 0.29; 95% CI, 0.10–0.48), inversion range of motion (SMD = 0.37; 95% CI, 0.10–0.63), eversion strength (SMD = 0.37; 95% CI, 0.10–0.65), and dynamic arch height change during walking (SMD = 1.05; 95% CI, 0.49–1.60) were significant risk factors for MTSS. Egger’s regression analysis revealed asymmetry in several variables, which indicates publication bias. The trim-and-fill method was applied to these variables. A comparison between the SMD and adjusted SMD showed that the variables had minimal impacts on the meta-analysis. Conclusions: Based on our results, health care professionals should assess the significant risk factors in patients before participation in physical activities and treat them to prevent and rehabilitate MTSS.