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PURPOSE This study aimed to: 1) compare the differences in static lower-extremity alignment (SLEA) between female ballet dancers (BD) and non-ballet dancers (NBD); 2) investigate the differences among gesture leg (GL) and supporting leg (SL) in BD and dominant leg (DL) in NBD; and 3) compare limb asymmetry between groups. METHODS Twenty-nine female BD and 20 NBD were recruited for this study. The quadriceps, tibiofemoral, rearfoot, and genu-recurvatum angles, tibial torsion and varum, and navicular drop height were measured. An independent t-test was conducted to compare SLEA and limb asymmetry between groups. One-way analysis of variance with Bonferroni post-hoc tests were performed to determine the differences among the GL, SL and DL. RESULTS BD showed lower quadriceps and rearfoot angles, less tibial varum and navicular drop, and greater tibiofemoral angle (p

PURPOSE The purpose of this study was to investigate the characteristics of field and on-ice performances of ice-hockey players and the relationship of performance with subjective joint pain and dysfunction. METHODS A total of 25 male college icehockey players were evaluated for 19 items of performance. Pain and dysfunctions in the lower extremities and lower back were confirmed through the Foot and Ankle Outcome Score, Knee Injury and Osteoarthritis Outcome Score, Hip Dysfunction and Osteoarthritis Outcome Score, and Osweatry Disability Index questionnaire. Players with similar performance characteristics were classified through a cluster analysis, and differences in performance and patient-reported outcomes between clusters were analyzed with a one-way analysis of variance. RESULTS The ice-hockey players were classified into “lower muscular strength and performance (cluster 1),” “lower cardiorespiratory endurance (cluster 2),” and “high muscular strength and performance (cluster 3).” Players in cluster 1 had more frequent ankle and knee joint dysfunctions and pain compared to those in cluster 3. Several performance test items affected the subjective joint score, and the related performance items were more in the proximal joint than in the distal joint. CONCLUSIONS Ice hockey players should perform training to supplement their individual lack of on-ice and field performance. Since performance may be limited because of joint dysfunction and pain, a joint-specific intervention strategy should be applied to improve physical and athletic performances.

Chronic ankle instability (CAI) patients often exhibit postural control deficits and rely on visual information to maintain static balance to compensate for decreased proprioception. Fatigue impairs neuromuscular control, in addition to postural control, in CAI patients. However, whether functional fatiguing exercises alter postural control and sensory organization strategies during single-leg balance tests in CAI patients remains unclear. This study involved a controlled trial on 28 CAI patients in a laboratory setting. Each participant performed a single-leg balance test with eyes open (EO) and eyes closed (EC) before and after a functional fatigue protocol. Two-way repeated-measures ANOVA evaluated fatigue (pre- vs. post-fatigue) × vision (EO vs. EC) interactions for outcome variables. Additionally, paired-sample t-tests examined differences between two conditions (pre- vs. post-fatigue) for time-to-boundary (TTB) minima (%modulation). We found significant interactions between fatigue and vision conditions in ML and AP TTBmeans and AP TTBsds. %Modulations were significantly decreased after fatigue in AP TTBmean, ML TTBsd, and AP TTBsd. In conclusion, static postural control ability decreased after the functional fatigue protocol with EO, but was unchanged with EC. This suggests that decreased balance ability is more pronounced with EO under fatigue due to less visual dependence. This may increase ankle sprain incidence under fatigue.

This report presents the case of an ice hockey player diagnosed with a tear in the anterior horn of the lateral meniscus at 19 years of age. In addition, we suggest a rehabilitation exercise program that enabled an early return to play for an ice hockey athlete in a university sports league. The patient underwent arthroscopic meniscal repair and was discharged one day after surgery. A three-stage rehabilitation program was developed, as follows: Phase I, the protective phase (reduce inflammation symptoms and restore range of motion to enable weight-bearing); Phase II, the restorative phase (improve the strength of the quadriceps muscle and recover cardiovascular endurance); Phase III, the return to full functional activity (familiarize the patient with sport-specific skills and recover a symmetric functional level on both sides). After completing the 10-week rehabilitation program, the patient returned to play and took part in games 71 and 84 days after surgery. The patient had no meniscus reinjury in the 10 years after surgery while playing in university and professional ice hockey leagues. The functional performance-focused rehabilitation program presented in this case report resulted in an early return to sport and good long-term outcomes.

PURPOSE This study aimed to identify movement pattern differences in the running of youth soccer players with and without lateral ankle sprain (LAS) histories. METHODS A total of 12 participants were recruited and assigned to the LAS group or the control group. All participants were assessed for anthropometric data, and they filled in the subjective ankle function questionnaires. Then, reflective markers were attached to their bodies, and they were instructed to run at the preferred speed on the 9-m runway thrice. 3D joint angles for ankle, knee, and hip joints were exported, and their mean values and 95% confidence intervals were calculated. Ensemble curve analysis was conducted to compare running kinematics between the groups. RESULTS The LAS group exhibited fewer dorsiflexion angles and more inversion angles compared to the control group. Excluding the dorsiflexion deficits and more inverted ankles, there were no significant differences between the groups. CONCLUSIONS Although the ankle kinematic patterns found in this paper are not considered LAS risk factors, it will be able to identify precise LAS risk factors with prospective design (e.g., lower extremity movement patterns) as well as intrinsic risk factors.

OBJECTIVES This study examined the immediate effect of unilateral ankle or knee joint cooling on the low-erextremity kinematics and kinetics during two-legged jumping and landing. METHODS Twenty healthy adults randomly completed three data collection sessions for ankle or knee joint cooling, or control. For each session, participants performed two-legged countermovement jumps and lands. For joint cooling, two ice bags were directly placed to the right side and secured with a compression bandage. A three-dimensional motion analysis system (200 Hz) with two floor-embedded force platforms (2000 Hz) was employed to capture the jumping and landing. The cooling effects on kinematical (flight time, and sagittal plane joint angles) and kinetical (peak vertical ground reaction force (vGRF), impulse, and sagittal plane joint moments) variables were examined. A mixed-model analysis of variance was performed for each dependent variable (p≤0.0001 for all tests). RESULTS We did not observe any interactions (flight time: F2,95=0.67, p=0.52; joint angles: F2,209≤2.26, p≥0.10; peak vGRF: F2,209≤1.76, p≥0.20; impulse: F2,209≤2.54, p≥0.10; joint moments: F2,209≤4.80, p≥0.01 for all interactions). Regardless of condition and time (side effect), subjects showed a dominant-leg predominant movement strategy. Specifically, the right side showed a greater peak vGRF (2%), and greater ankle (7%), knee (6%), and hip (11%) joint moments, as compared with the left side during jumping. The same movement pattern was observed during landing that there was greater peak vGRF (11%) and impulse (8%), and greater ankle and knee joint moments (15%). Regardless of time and side (condition effect), subjects with ankle joint cooling showed 5% lesser ankle joint moment during jumping, compared with those who received knee joint cooling (p=0.0001). CONCLUSIONS A 20-min of unilateral ankle or knee joint cooling seems to neither alter vertical jump height nor change movement biomechanics during two-legged jumping and landing.

Lateral ankle sprain (LAS) is the most common injury in Korean adolescent soccer players. However, intrinsic risk factors for LAS in adolescent soccer players remain unclear. Therefore, this prospective cohort study aimed to identify intrinsic risk factors for LAS in Korean adolescent soccer players. This study included 100 adolescent soccer players (age=13.21±0.95 years, height=1.62±0.09 m, weight=53.37±9.54 kg, BMI-for-age percentile=63.78±20.89%, athletic career=3.95±1.96 years). Baseline measurements were performed in the preseason, and the injury surveillance on LAS was conducted for 1 year. Independent variables included participants' demographic and anthropometric data, self-reported questionnaire, lower extremity alignments, range of motion, static, and dynamic balance, coordination, and ankle kinematics during running. Independent t-test and Chi-square analysis were used for potential risk factors, which were imported to the binary logistic regression to identify intrinsic risk factors for LAS. Data on intrinsic risk factors identified by the logistic regression were analyzed using the receiver operating characteristic curve analysis to determine a cutoff point of each variable. In this study, age, body mass index, previous LAS history, the number of LAS history, and maximum dorsiflexion and inversion during the stance phase of running were potential risk factors for LAS. Our major findings showed that decreased dorsiflexion and increased inversion at initial contact during running significantly affected LAS occurrence in Korean adolescent soccer players. Considering our major findings, to prevent LAS in adolescent soccer players, gait training must not be overlooked and should be included in warm-up sessions. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study was to investigate how the ball position along the mediolateral (M-L) direction of a golfer causes a chain effect in the ground reaction force, body segment and joint angles, and whole-body centre of mass during the golf swing. Twenty professional golfers were asked to complete five straight shots for each 5 different ball positions along M-L: 4.27 cm (ball diameter), 2.14 cm (ball radius), 0 cm (reference position at preferred ball position), – 2.14 cm, and – 4.27 cm, while their ground reaction force and body segment motions were captured. The dependant variables were calculated at 14 swing events from address to impact, and the differences between the ball positions were evaluated using Statistical Parametric Mapping. The left-sided ball positions at address showed a greater weight distribution on the left foot with a more open shoulder angle compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. These trends disappeared during the backswing and reappeared during the downswing. The whole-body centre of mass was also located towards the target for the left-sided ball positions throughout the golf swing compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. We have concluded that initial ball position at address can cause a series of chain effects throughout the golf swing.

PURPOSE We examined the immediate effect on ankle or knee joint cooling on the lower-extremity activation during a single-leg drop jump. METHODS Twenty healthy adults randomly completed three data collection sessions (a 20-minute ankle or knee joint cooling, or control). Two wireless surface electromyography (EMG, 2,000 Hz) electrodes were attached over the vastus medialis (VM) and the medial gastrocnemius (MG) on their right limb. Subjects were asked to drop down from a wooden box (a 30-cm height) on their right foot onto the force platform (2,000 Hz) and then performed an immediate jump as high as they could. Whole EMG signals (normalised by the mean EMG value recorded during a reference position) within the preactivation (100-ms prior to contact) and the ground contact (on the force platform) during the drop jump task were analysed using functional linear models(p=.05, Cohen’s d effect size: ES). RESULTS After knee joint cooling, (1) the VM activation was decreased during the ground contact (6 to 14%, 30 to 45%, 60 to 90% for ES of 0.50, 0.47, and 0.61, respectively) and (2) the MG activation was increased during the preactivation (84- to 29-ms prior to initial contact, ES=1.30) and the ground contact (59 to 100%, ES=1.40). No changes were observed under the condition of ankle joint cooling or control. CONCLUSIONS A 20-minute unilateral knee joint cooling may result in an ipsilateral quadriceps inhibition during a drop jump task. The gastrocnemius appears to increase activation as a compensatory strategy responding to the quadriceps inhibition. The altered neuromuscular activations do not seem to put an individual at risk of injury, resulting from compressive forces in the sagittal plane.

Landing on a single-leg without receiving direct visual information (e.g., not looking at the ground) may increase the risk of injury. We examined whether visual focus contributed to the changing lower-extremity dynamics and patellofemoral joint stress during a single-leg drop jump task. Twenty healthy volunteers visited the laboratory for three separate sessions. During each session, participants randomly performed either of two types of a single-leg drop jump task from a 30 cm high wooden box. Subsequently, participants looked at the landing spot (central vision condition) or kept their heads up (peripheral vision condition) when performing the task. Sagittal and frontal plane lower-extremity joint angles and joint moments (in the ankle, knee, and hip), including the vertical ground reaction force, and patellofemoral joint stress during the first landing phase (from initial contact to peak knee flexion) were compared. Greater ankle inversion and hip adduction were observed when landing with the peripheral vision condition. However, the magnitudes were negligeable (Cohen’s d effect size

Context: It is unclear if lower-extremity joint cooling alters biomechanics during a functional movement. Objective: To investigate the effects of unilateral lower-extremity cryotherapy on movement alterations during a single-leg drop jump. Design: A crossover design. Setting: Laboratory. Patients: Twenty healthy subjects (10 males and 10 females; 23 y, 169 cm, 66 kg). Intervention(s): Subjects completed a single-leg drop jump before and after a 20-minute ankle or knee joint cooling on the right leg, or control (seated without cooling) on 3 separate days. Main outcome measures: Time to peak knee flexion, vertical ground reaction force, lower-extremity joint angular velocity (sagittal plane only), and angle and moment (sagittal and frontal planes) in the involved leg over the entire ground contact (GC; from initial contact to jump-off) during the first landing. Time to peak knee flexion was compared using an analysis of variance; the rest of the outcome measures were analyzed using functional analyses of variance (P < .05). Results: Neither joint cooling condition changed the time to peak knee flexion (F2,95 = 0.73, P = .49). Ankle joint cooling reduced vertical ground reaction force (55 N at 4% of GC), knee joint angular velocity (44°/s during 5%-9% of GC), and knee varus moment (181 N·m during 18%-20% of GC). Knee joint cooling resulted in a reduction in knee joint angular velocity (24°/s during 37%-40% of GC) and hip adduction moment (151 N·m during 46%-48% of GC), and an increase in hip joint angular velocity (16°/s during 49%-53% of GC) and plantarflexion angle (1.5° during 11%-29% of GC). Conclusion: Resuming activity immediately after lower-extremity joint cooling does not seem to predispose an individual to injury during landing because altered mechanics are neither overlapping with the injury time period nor of sufficient magnitude to lead to an injury. [ABSTRACT FROM AUTHOR]

Background: Knee disease is prevalent in the post middle-aged and associated with lower quality of life. Knee disease (i.e., anterior cruciate ligament, ACL) related injury preventive program should be supported. We examined the significant effect of different age, gender, and exercise modalities on measureable nine dependent markers in National Health Insurance Sharing Service database (NHISS DB) registered ACL patients using big data analysis. Methods: The 1755 ACL patients from 514,866 in NHISS DB have been randomly selected by retrospective cohort study using big data from 2002 to 2013. Six independent and 9 dependent variables were used for analyzing patients with ACL injuries by T-test and Two-way analysis of variance (ANOVA). Results: Mean (SD) (men vs. women) of BMI, high blood pressure (BP), serum glutamic oxaloacetic transaminase (SGOT), and total cholesterol were 24.38±2.72 vs. 24.86±3.12 (P

Female Korean professional soccer players endure a high burden of injuries throughout their careers. This retrospective study investigated their injury history characteristics by surveying 181 players across eight Korea Women's Football Federation teams. The survey covered demographics, playing positions, career spans, dominant legs, national team memberships, and detailed information on previous injuries, including location, type, mechanism, and severity. Analysis revealed lower extremities as the most vulnerable region, injured in 44.7% of competitions, and 46.6% of practice sessions, followed by foot and ankle injuries. Joint and ligament injuries dominated, comprising 45.0% of competition-related incidents, and 55.2% of those sustained during practice. Notably, contact was the primary mechanism for practice injuries (49.8%), while overuse (33.4%) and contact (33.2%) shared the blame in competitions. Interestingly, severe injuries were significantly more prevalent in practice (65.2%) compared to competitions (48.2%). Almost all players had at least one previous injury, often affecting the lower extremities. This highlights the need for targeted preventive measures addressing the high prevalence of severe joint and ligament injuries, often exacerbated by aggressive situations. These findings emphasize the crucial need for tailored injury prevention strategies specifically designed for the unique demands and challenges faced by women's soccer players. [ABSTRACT FROM AUTHOR]

Gait analysis has historically been implemented in laboratory settings only with expensive instruments; yet, recently, efforts to develop and integrate wearable sensors into clinical applications have been made. A limited number of previous studies have been conducted to validate inertial measurement units (IMUs) for measuring ankle joint kinematics, especially with small movement ranges. Therefore, the purpose of this study was to validate the ability of available IMUs to accurately measure the ankle joint angles by comparing the ankle joint angles measured using a wearable device with those obtained using a motion capture system during running. Ten healthy subjects participated in the study. The intraclass correlation coefficient (ICC) and standard error of measurement were calculated for reliability, whereas the Pearson coefficient correlation was performed for validity. The results showed that the day-to-day reliability was excellent (0.974 and 0.900 for sagittal and frontal plane, respectively), and the validity was good in both sagittal (r = 0.821, p < 0.001) and frontal (r = 0.835, p < 0.001) planes for ankle joints. In conclusion, we suggest that the developed device could be used as an alternative tool for the 3D motion capture system for assessing ankle joint kinematics.

Objective This paper aims to describe the medical service of two polyclinics of the PyeongChang Winter Olympic Games and to analyse the injury and illness of athletes who visited the polyclinics during the oilympic period in order to provide some insight with respect to the future construction and operation of polyclinics in mass gathering events such as the Olympic Games.Methods The PyeongChang Olympic Village was located near the Olympic Stadium for snow sports athletes and the Gangneung Olympic Village was located near the ice venues for ice sports athletes. During the Olympic Games, polyclinics were consisted of emergency service and outpatient clinics. We retrospectively analysed the electronic medical record data of athletes who visiting polyclinics between 9 February 2018 and 25 February 2018.Results During the Olympics, there were 1639 athlete encounters in both polyclinics. Among those, injuries of athletes were 237 (14% of all athlete encounters) in total, and the most common injured site was knee joint. Upper respiratory infection was the most frequent case in diseases of athlete encounters. Total 223 cases of image study were done, MRI was 44 cases.Conclusion The PyeongChang Winter Olympic Games had the highest number of participants in the history of Winter Olympic Games. Overall 48% of athletes encountered polyclinics due to disease during the Games period. Upper respiratory infection and other seasonal diseases were more frequent this Olympic Games than before. Polyclinics were managed healthcare of athletes as well as injury and illness of athletes. In winter sports, a polyclinic and similar medical facilities should be prepare for diseases considering geography, weather as well as injuries and endemic diseases when planning future mass gathering events.

Context: Clinically, it has been suggested that increased activation of intrinsic foot muscles may alter the demand of extrinsic muscle activity surrounding the ankle joint in patients with stage II posterior tibial tendon dysfunction. However, there is limited empirical evidence supporting this notion. Objective: The purpose of this study was to investigate the effects of a 4-week short-foot exercise (SFE) on biomechanical factors in patients with stage II posterior tibial tendon dysfunction. Design: Single-group pretest-posttest. Setting: University laboratory. Participants: Fifteen subjects (8 males and 7 females) with stage II posterior tibial tendon dysfunction who had pain in posterior tibial tendon, pronated foot deformity (foot posture index ≥+6), and flexible foot deformity (navicular drop ≥10 mm) were voluntarily recruited. Intervention: All subjects completed a 4-week SFE program (15 repetitions x 5 sets/d and 3 d/wk) of 4 stages (standing with feedback, sitting, double-leg, and one-leg standing position). Main outcome measures: Ankle joint kinematics and kinetics and tibialis anterior and fibularis longus muscle activation (% maximum voluntary isometric contraction) during gait were measured before and after SFE program. Cohen d effect size (ES [95% confidence intervals]) was calculated. Results: During the first rocker, tibialis anterior activation decreased at peak plantarflexion (ES = 0.75 [0.01 to 1.49]) and inversion (ES = 0.77 [0.03 to 1.51]) angle. During the second rocker, peak dorsiflexion angle (ES = 0.77 [0.03 to 1.51]) and tibialis anterior activation at peak eversion (ES = 1.57 [0.76 to 2.39]) reduced. During the third rocker, the peak abduction angle (ES = 0.80 [0.06 to 1.54]) and tibialis anterior and fibularis longus activation at peak plantarflexion (ES = 1.34 [0.54 to 2.13]; ES = 1.99 [1.11 to 2.86]) and abduction (ES = 1.29 [0.50 to 2.08]; ES = 1.67 [0.84 to 2.50]) decreased. Conclusions: Our 4-week SFE program may have positive effects on changing muscle activation patterns for tibialis anterior and fibularis longus muscles, although it could not influence their structural deformity and ankle joint moment. It could produce a potential benefit of decreased tibialis posterior activation. [ABSTRACT FROM AUTHOR]

This review aimed to analyze the impact of whole-body-vibration (WBV) training on strength, power, muscle endurance, functional lower-extremity flexibility (FLEF), and functional lower-extremity strength (FLES) in older adults and to evaluate the effectiveness of different WBV training periods. Electronic searches were conducted using four databases. The methodological quality and level of evidence of the selected articles were assessed by two reviewers. Standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated. Nineteen studies were included (474 participants; mean age 74.27 years). Strength was measured by isokinetic, isometric, or isotonic contraction using an isokinetic dynamometer or weight-training machines. Power was measured by an assessment task that required maximal force in a short period of time. Endurance was evaluated by maximal repetition of tasks, FLEF by chair stand-and-reach and functional reach tests, and FLES by the sit-to-stand test. Meta-analysis showed that WBV training had significant effects on strength (SMD = .54; CIs = .40, .67), power (SMD = .58; CIs = .28, .89), muscle endurance (SMD = .82; CIs = .36, 1.29), FLEF (SMD = .31; CIs = .06, .55), and FLES (SMD = -.75; CIs = -1.18, -.33). Our findings suggest that 1) WBV training improves overall lower-extremity muscle function in older adults, especially muscle endurance; 2) a minimum of 8 weeks of WBV training is recommended to improve strength, muscular endurance, and power; and 3) a longer period of the WBV training is more effective at improving muscle endurance, power, and strength but not FLEF and FLES. Therefore, WBV training is strongly recommended to improve various muscle function parameters in older adults. [ABSTRACT FROM AUTHOR]