No beneficial effect of aerobic whole-body electromyostimulation on lower limbs strength and power - a randomized controlled trial.

BACKGROUND: Applying whole-body electromyostimulation (wbEMS) to voluntary activation of the muscle is known to impact motor unit recruitment. Thus, wbEMS as an additional training stimulus enhances force-related capacities. This study aimed to evaluate the mono- and multiarticular strength adaptations to a running intervention with wbEMS compared to running without wbEMS. METHODS: In a randomized controlled trial (RCT), 59 healthy participants (32 female/ 27 male, 41 ± 7 years) with minor running experience conducted an eight-week running intervention (2x/ week à 20 min) with a wbEMS suit (EG) or without wbEMS (control group, CG). Maximal isokinetic knee extensor and flexor strength and jump height during countermovement jumps were recorded prior and after the intervention to assess maximal strength and power. RESULTS: Following eight weeks of running, maximal isokinetic knee extension torque decreased significantly over time for both interventions (EG Δ -4%, CG Δ -4%; F(1, 44.14) = 5.96, p = 0.02, η = 0.12). No changes were observed for flexion torque (F(1, 43.20) = 3.93, p = 0.05, η = 0.08) or jump height (F(1, 43.04) = 0.32, p = 0.57, η  = 0.01). CONCLUSIONS: The outcomes indicate that there is no additional effect over neuromuscular function adaptations with the inclusion of wbEMS during running training. Knee extensor strength is even slightly reduced which supports the principle of training specificity in regards to strength adaptation. We conclude that strength improvements cannot be achieved by running with wbEMS. TRIAL REGISTRATION: German Clinical Trials Register, ID DRKS00026827, date 10/26/21.

Epidemiology of Injuries in Olympic Sports.

Injuries effect the performance of athletes. Severity of injuries is determined by time loss and sporting performance reduction. To treat injuries adequately, it is necessary to get an overview of varied injuries types in different sports disciplines. In a retrospective study 7.809 athletes from Germany, Switzerland and Austria competing in competitive or recreational levels of sports were included. Injury prevalence was highest in team sports (75 %), followed by combat (64 %), racquet (54 %) and track and field (51 %). Knee (28 %) and shoulder (14 %) were the most at risk joints. Time loss in sporting activity after injury was longest in the region of knee (26 weeks). Of all reported injuries, 48 % were accompanied by a reduced level of performance. The highest injury prevalence occurred in the year 2016 (45 %). More injuries occurred during training (58 %) compared to competition (42 %). Across Olympic disciplines, a large number of injuries occurred during training sessions. Injury frequency increased as the Olympic games drew closer. Knee and shoulder injuries were the most severe injuries with respect to time loss and reduction sporting performance.

Energy transfer in reactive movements as a function of individual stretch load.

Background: By directly recording electromyographic activity profiles and muscle-tendon interaction, this study aimed to elucidate the mechanisms why well-trained track and field athletes (experts) are able to outperform untrained individuals without former systematic experience in reactive jump training (novices). In particular, reactive power output and the elastic recoil properties of the muscle-tendon unit (MTU) were of special interest. For this purpose, stiffness regulation on muscle and joint level, energy management in terms of storing or dissipating elastic energy were compared between experts and novices during various stretch loads. Methods: Experts were compared with novices during reactive drop jumps (DJs) from drop heights ranging between 25 and 61 cm. Delta kinetic energy (Ekin) was calculated as the difference between the Ekin at take-off and ground contact (GC) to determine energy management. By recording electromyography of the lower limb muscles, in vivo fascicle dynamics (gastrocnemius medialis) and by combining kinematics and kinetics in a 3D inverse dynamics approach to compute ankle and knee joint kinetics, this study aimed to compare reactive jump performance, the neuromuscular activity and muscle-tendon interaction between experts and novices among the tested stretch loads. Results: Experts demonstrated significantly higher power output during DJs. Among all drop heights experts realized higher delta Ekin compared to novices. Consequently, higher reactive jump performance shown for experts was characterized by shorter GC time (GCT), higher jump heights and higher neuromuscular activity before and during the GC phase compared to novices. Concomitantly, experts were able to realize highest leg stiffness and delta Ekin in the lowest stretch load; however, both groups compensated the highest stretch load by prolonged GCT and greater joint flexion. On muscle level, experts work quasi-isometrically in the highest stretch load, while in novices GM fascicles were forcefully stretched. Conclusion: Group-specific stiffness regulation and elastic recoil properties are primarily influenced by the neuromuscular system. Due to their higher neuromuscular activity prior and during the GC phase, experts demonstrate higher force generating capacity. A functionally stiffer myotendinous system through enhanced neuromuscular input enables the experts loading their elastic recoil system more efficiently, thus realizing higher reactive power output and allowing a higher amount of energy storage and return. This mechanism is regulated in a stretch load dependent manner.

Running with whole-body electromyostimulation improves physiological determinants of endurance performance - a randomized control trial.

BACKGROUND: This study aimed to evaluate the physiological and metabolic adaptations to an eight-week running intervention with whole-body electromyostimulation (wbEMS) compared to running without wbEMS. METHODS: In a randomized controlled trial (RCT), 59 healthy participants (32 female/ 27 male, 41 ± 7 years, rel.V̇O2max 40.2 ± 7.4 ml/min/kg) ran twice weekly à 20 min for eight weeks either with a wbEMS suit (EG) or without wbEMS (control group, CG). Before and after the intervention, (i) rel.V̇O2max, heart rate and time to exhaustion were recorded with an incremental step test with an incremental rate of 1.20 km/h every 3 min. They were interpreted at aerobic and (indirect) anaerobic lactate thresholds as well as at maximum performance. (ii) Resting metabolic rate (RQ) as well as (iii) body composition (%fat) were assessed. RESULTS: Following the intervention, V̇O2max was significantly enhanced for both groups (EG ∆13 ± 3%, CG ∆9 ± 3%). Velocity was elevated at lactate thresholds and maximum running speed (EG ∆3 ± 1%, CG ∆2 ± 1%); HRmax was slightly reduced by -1 beat/min. No significant changes were observed for time until exhaustion and lactate. RQ was significantly enhanced following both trainings by + 7%. %fat was reduced for both groups (EG ∆-11 ± 3%, CG ∆-16 ± 5%), without any changes in body mass. Results did not differ significantly between groups. CONCLUSIONS: Both interventions had a positive impact on aerobic power. The rightward shift of the time-velocity graph points towards improved endurance performance. The effects of wbEMS are comparable to those after high-intensity training and might offer a time-efficient alternative to affect physiological and metabolic effects. TRIAL REGISTRATION: German Clinical Trials Register, ID DRKS00026827, date 10/26/21.

Return to sport after conservative treatment of elbow dislocation in judoka.

BACKGROUND: Injuries to the elbow are frequent in judo combat, but studies on down-time and effect on performance after conservative treatments are rare. This issue is particularly relevant for elbow dislocations in high-performance patients such as elite athletes. The purpose of this study was to evaluate (1) time-loss and (2) the regained level of performance in judoka after conservative treatment of simple elbow dislocation. METHODS: In cooperation with the European Judo Union, judoka were asked to complete a 139-item survey regarding elbow injuries they suffered during their career. Besides demographics, injury data, diagnosis and treatment options, the athletes were asked about down-time and reductions in performance level. This study enrolled 108 judoka with conservative treatment of elbow dislocation out of a population of 5426 volunteers. RESULTS: 69% (n=74) reported a time-loss of less than three months; 6% reported a time-loss of more than six months. The majority (68%, n=73) reported that they had returned to their previous performance level, while 22% (n=24) suffered from a slightly reduced level of performance. In the subgroup of international and national athletes (n=54), 63% returned to judo after less than three months, with 72% achieving the same level and 15% reporting a slightly reduced performance level. Level of performance and time lost after conservative treatment for elbow dislocations were comparable for male and female judoka. CONCLUSION: Approximately two out of three judoka returned to the same level of performance after three months of down-time after undergoing conservative therapy for simple elbow dislocations. Despite the high performance level of the study population, conservative treatment of simple elbow dislocation resulted in satisfactory outcomes. The presented data can guide medical professionals and competitive-level contact-sport athletes with respect to expectations in the process of returning to sport.

Early ACL reconstruction shows an improved recovery of isokinetic thigh muscle strength compared to delayed or chronic cases.

INTRODUCTION: The recovery of periarticular strength is a major criterion in return-to-play testing. The rationale of the study was to assess the impact of the delay of surgery (∆ between injury and surgery) on knee extensor and knee flexor strength of anterior cruciate ligament (ACL)-deficient patients six months after reconstruction. MATERIALS AND METHODS: In a retrospective cohort study, all patients with ACL ruptures between 03/2015 and 12/2019 were analyzed. Inclusion criteria were isolated ACL rupture without any associated lesions undergoing a reconstruction using ipsilateral hamstring tendon autograft and adherence to isokinetic strength testing before and at 5-7 months postoperatively. These patients were then clustered into three groups: EARLY reconstruction (∆ < 42 days), DELAYED reconstruction (∆42-180d), and CHRONIC (∆ > 180d). Knee extensor and flexor strength of the ipsi- and contralateral leg were analyzed by concentric isokinetic measurement (60°/s). Primary outcomes were the maximal knee extension and flexion torque, hamstrings-to-quadriceps ratio (H/Q) ratio), and the corresponding limb symmetry indices. RESULTS: n = 444 patients met the inclusion criteria. From EARLY to DELAYED to CHRONIC, a progressive reduction in postoperative strength performance was observed in knee extension (1.65 ± 0.45 to 1.62 ± 0.52 to 1.51 ± 0.5 Nm/kg resp.) and flexion (1.22 ± 0.29 to 1.18 ± 0.3 to 1.13 ± 0.31 Nm/kg resp.) strength on the ACL reconstructed leg. This general loss in periarticular strength was already apparent in the preoperative performance even on the healthy side. When controlling for the preoperative performance using ANCOVA analysis, EARLY performed significantly better than DELAYED (extension p = 0.001, flexion p = .02) and CHRONIC (extension p = 0.005, flexion p < 0.001). Also, there were significantly higher values for H/Q ratio in the injured leg across all groups where the H/Q ratio increased from EARLY to CHRONIC and from pre- to postoperative values. CONCLUSIONS: With respect to the force generating capacity when returning-to-play, it is advantageous to seek for an early ACL reconstruction within the first 12 weeks after the injury. The increasing loss of thigh muscle strength observed in delayed or chronic cases affects the injured and also the non-injured leg. LEVEL OF EVIDENCE: III, retrospective cohort study.

Development and validation of a clinical prediction model for return to work after arthroscopic anterior crucial ligament reconstruction.

BACKGROUND: Occupational reintegration after anterior cruciate ligament (ACL) rupture is an important clinical issue including economic and health-related perspectives. This study aims to develop and validate a clinical prediction model of return to work in patients with ACL reconstruction surgery considering evidence-based clinical, anthropometric and occupational factors. METHODS: Data of 562 patients with an ACL rupture receiving an arthroscopic ACL reconstruction were used for analysis. A model for the binary outcome of experiencing an inability to work period of less or more than 14 days (model 1), and a model for finding predictor variables that are linearly associated with a continuous longer inability to work period of over 14 days (model 2) was calculated. Pre-operative determinants including patient characteristics and peri-operative factors were used as predictors for both models. RESULTS: For model 1, the highest increase in odds was observed for the occupational type of work, followed by injury of the medial collateral ligament together with partial weight bearing. Small protective effects were observed for female sex, meniscal suture and work with light occupational strain. The type of occupational work, together with revision surgery, a longer duration of limited range of motion and the presence of cartilage therapy were risk factors for longer inability to work. Discrimination and calibration statistics were satisfactory in internal validation. CONCLUSION: Within the framework of clinical consideration, these prediction models will serve as an estimator for patients, their treating physicians and the socioeconomic partners to forecast the individual cost and benefit of ACL injury.

Psychological readiness is related to return to sport in judo injuries: a cross-sectional study.

BACKGROUND: The aim of this study is to investigate the influence of a judoka's psychological readiness in relation to his ability to return to sport. At the present time, the relationship between physical and psychological readiness to return to sport has not been adequately elucidated. METHODS: This is a cross-sectional study. An online survey was distributed via social networks and the German Judo Association collecting data from competitive and recreational judo athletes. The survey collected data on participants' characteristics, history of injury, and psychological readiness to return to sport after injury as determined by either the Anterior Cruciate Ligament-Return to Sport after Injury Scale, the Shoulder Instability-Return to Sport after Injury Scale, or a modified version of the Return to Sport after Injury Scale depending on the respective type of injury. RESULTS: The study included 383 judo athletes (272 competitive judo athletes and 112 recreational judo athletes). Regardless of injury location, athletes who achieved return to sports (M = 70.67; SD = 16.47) had higher RSI scores than athletes that did not return to sports (M = 53.88; SD = 19.12; p < 0.0001). Male athletes (M = 65.60; SD = 19.34) did show significantly higher RSI scores than female athletes (M = 60.45; SD = 19.46). The RSI score differed for different time loss categories, F(7, 375) = 11.309, p < 0.001, η2 = .174 with decreasing RSI scores for longer time loss and lowest RSI scores in athletes, who never returned to sports. RSI scores of athletes with knee injuries differed from athletes with other injury locations (10.23, 95% CI [4.08, 16.38]). After adjusting for time loss due to injury, competitive athletes had higher RSI scores than competitive athletes (F (1, 382) = 7.250, p < 0.001, partial η2 = .02). Conservatively treated athletes (M = 66.58; SD = 18.54) had higher RSI scores than surgically treated athletes (M = 59.05; SD = 20.01; p < 0.05). CONCLUSION: Based on the data of this study, type of injury, sport level, treatment method, and gender appear to influence psychological readiness on judoka and their ability to return to sport. The multiple factors that influence a judoka and their ability to return to sport argue for individualized treatment of judoka and their psychological state after injury in the return to sport process.

Whole-Body Electromyostimulation Impacts Physiological Responses During Aerobic Running: A Randomized Trial.

Objective: The aim of the current study was to evaluate the physiological and metabolic responses to running with whole-body electromyostimulation (wbEMS) compared to running without electromyostimulation (control, CG). Methods: Twenty healthy participants (9 male/11 female, age 42 ±7 years) conducted an incremental step test with respiratory gas analysis until exhaustion. Trials were conducted as wbEMS and CG in a random order. As outcome measures, (A) objective total exhaustion, (B) athletic responses (max. time and velocity) and (C) physiological and metabolic responses (V'O2/ kg, V'E, EE, RER, lactate) were compared. (D) The impact on the skeletal muscle was assessed prior, 48 h & 72 h after trial. Results: During both trials, participants (A) ran until total exhaustion. Nonetheless, (B) time and velocity till exhaustion as well as (C) RER prior to the first lactate threshold and V'E were reduced with wbEMS. All other correlates did not differ significantly between wbEMS and CG. Following 48 h and 72 h after the trial with wbEMS, (D) the impact on the skeletal muscle was 7- to 9-fold higher compared to baseline values. Values differed significantly to those after running without wbEMS. Conclusion: With the additional stimulation during voluntary activation, wbEMS induces earlier fatigue and a shift in energy metabolism toward fat utilization. Even during aerobic endurance tasks, a great impact on the skeletal muscle indicated by the rise in CK could be observed which promotes wbEMS as an alternative training stimulus that is easy-to-apply and effective during endurance training.

Changes in gravity affect neuromuscular control, biomechanics, and muscle-tendon mechanics in energy storage and dissipation tasks.

This study evaluates neuromechanical control and muscle-tendon interaction during energy storage and dissipation tasks in hypergravity. During parabolic flights, while 17 subjects performed drop jumps (DJs) and drop landings (DLs), electromyography (EMG) of the lower limb muscles was combined with in vivo fascicle dynamics of the gastrocnemius medialis, two-dimensional (2D) kinematics, and kinetics to measure and analyze changes in energy management. Comparisons were made between movement modalities executed in hypergravity (1.8 G) and gravity on ground (1 G). In 1.8 G, ankle dorsiflexion, knee joint flexion, and vertical center of mass (COM) displacement are lower in DJs than in DLs; within each movement modality, joint flexion amplitudes and COM displacement demonstrate higher values in 1.8 G than in 1 G. Concomitantly, negative peak ankle joint power, vertical ground reaction forces, and leg stiffness are similar between both movement modalities (1.8 G). In DJs, EMG activity in 1.8 G is lower during the COM deceleration phase than in 1 G, thus impairing quasi-isometric fascicle behavior. In DLs, EMG activity before and during the COM deceleration phase is higher, and fascicles are stretched less in 1.8 G than in 1 G. Compared with the situation in 1 G, highly task-specific neuromuscular activity is diminished in 1.8 G, resulting in fascicle lengthening in both movement modalities. Specifically, in DJs, a high magnitude of neuromuscular activity is impaired, resulting in altered energy storage. In contrast, in DLs, linear stiffening of the system due to higher neuromuscular activity combined with lower fascicle stretch enhances the buffering function of the tendon, and thus the capacity to safely dissipate energy.NEW & NOTEWORTHY For the first time, the neuromechanics of distinct movement modalities that fundamentally differ in their energy management function have been investigated during overload systematically induced by hypergravity. Parabolic flight provides a unique experimental setting that allows near-natural movement execution without the confounding effects typically associated with load variation. Our findings show that gravity-adjusted muscle activities are inversely affected within jumps and landings. Specifically, in 1.8 G, typical task-specific differences in neuromuscular activity are reduced during the center of mass deceleration phase, resulting in fascicle lengthening, which is associated with energy dissipation.

Muscle Architecture, Morphology, and Mechanical and Functional Properties of Biceps Femoris Long Head in Professional Soccer Players with a Prior Healed Injured Hamstring.

OBJECTIVE: The aim of the present study was to compare the fascicle length, pennation angle, muscle thickness and stiffness of the biceps femoris long head, and eccentric hamstring strength between injured dominant limbs, injured non-dominant limbs, uninjured dominant limbs and uninjured non-dominant legs in previously injured players, and between dominant and non-dominant legs in uninjured elite soccer players. MATERIALS AND METHODS: Twenty elite soccer players participated in this study. Ultrasound imaging and MyotonPRO were used to determine the morphological and mechanical properties of the biceps femoris long head. Isokinetic and Nordic hamstring exercises were used to assess eccentric hamstring strength. RESULTS: Previously injured players showed substantially lower fascicle length and muscle thickness, and significantly higher biceps femoris long head stiffness than uninjured players, without differences between limbs. CONCLUSION: The morphological and mechanical properties of elite soccer players with hamstring injury history were different from those in uninjured players. The lack of differences between limbs showed that these values are characteristics of individual players that must be considered in the design of programs to prevent BFlh injury.

Neuromuscular characteristics of agonists and antagonists during maximal eccentric knee flexion in soccer players with a history of hamstring muscle injuries.

BACKGROUND: Muscle strain injuries (MSIs) in the hamstrings are among the most prevalent injuries in elite soccer. We aimed to examine the relation between biomechanical maladaptation in eccentric strength and neuromuscular factors separated by their time and frequency domains. METHODS: 20 elite soccer players with a previous history of unilateral MSI in the M. biceps femoris (BF) long head and 20 without MSI participated. Knee flexion torques, rate of torque development (RTD) and electromyographic signals (EMG) of the BF, the M. semitendinosus (SMT) and knee extensors were obtained during unilateral maximal eccentric knee flexions performed at slow (30°/s) and fast (120°/s) angular speeds. Root mean squares and mean power frequency (MF) was calculated. RESULTS: In the group with a history of MSI, reduced maximal eccentric flexion torque (slow eccentrics -8±11, p<0.05; fast eccentrics -18±13 N*m, p<0.05) and RTD (-33±28 N*m/s, p<0.05; -95±47 N*m/s, p<0.05) concomitantly occurred with diminished agonistic myoelectrical activities (-4±5% of MVC, p<0.05; -10±7% of MVC, p<0.05) and MFs (-24±13 Hz, p<0.05; -24±18 Hz, p<0.05) in the BF. Simultaneously, antagonistic myoelectric activity was elevated (+4±3% of MVC, p<0.05; +3±3% of MVC, p<0.05) in MSI affected legs as compared to unaffected legs for both eccentric contractions. Deficits in myoelectrical activity (r2 = 0.715, p<0.05; r2 = 0.601, p<0.05) and MF (r2 = 0.484, p<0.05; r2 = 0.622, p<0.05) correlated with deficits in maximal torque in the affected leg in the MSI group. Analysis of SMT demonstrated no significant differences. CONCLUSION: Positive relationships between neuromuscular deficits and the reduced eccentric strength profile underpin neuronal inhibition after MSI. This persistent involvement of dysfunctional synergist and antagonist neural hamstring function in strength weakness is of clinical relevance in sports medicine for prevention and rehabilitation.

Pre-operative knee extensor and flexor torque after secondary ACL rupture: a comparative retrospective analysis.

BACKGROUND: Secondary anterior cruciate ligament (ACL) ruptures are a relevant clinical concern after surgical treatment of a primary ACL rupture. However, there is a lack of scientific evidence related to the role of muscle strength prior to revision surgery in a second ACL rupture. The aim of this study was to assess differences in knee extensor and flexor strength in patients before primary and secondary ACL reconstruction compared to healthy controls. METHODS: In total, n = 69 age, weight and sex matched individuals were included in the study: n = 23 patients with isolated primary ACL rupture, n = 23 with secondary ACL rupture, and n = 23 matched healthy controls. Maximal isokinetic knee extension and flexion torque normalized to body mass was assessed for both legs. RESULTS: For patients with secondary ACL ruptures, torques were reduced in the non-injured (extension: 1.94 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.25 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.70 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.14 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. For patients with a primary ACL rupture torques were reduced in the non-injured (extension: 1.92 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.24 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.38 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.01 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. There were no differences between patients with primary and secondary ruptures, except of the knee extension on the injured leg showing higher values after a secondary ACL rupture (1.38 Nm/kg vs. 1.70 Nm/kg, p < 0.05). CONCLUSIONS: The findings indicate that maximal knee torques were significantly reduced in patients with primary and secondary ACL ruptures before surgical reconstruction for the non-injured and injured leg as compared to healthy controls. Further investigations are needed to assess strength abilities before and after a second revision within a prospective design.

Six weeks of whole-body vibration improves fine motor accuracy, functional mobility and quality of life in people with multiple sclerosis.

People with multiple sclerosis (MS) suffer from sensorimotor deficits with the distal extremities being more severely affected than proximal ones. Whole-body vibration (WBV) training is known to enhance voluntary activation and coordination in healthy people. However, evidence about beneficial effects of WBV in MS patients is scarce. The current study aimed to investigate if six weeks of WBV enhances motor function in the ankle joint, coordination and quality of life in patients suffering from severe MS. In a longitudinal design, changes in motor function and quality of life were assessed before and after a 6-week control period without a training (CON) and a 6-week WBV training (2-3x/week) in 15 patients (53 ±10 years) with advanced MS (EDSS 3-6.5). Before CON (t0), after CON (t1) and after WBV(t2), outcome measures included (1) active range of motion (aROM) and (2) motor accuracy at the ankle joint, (3) functional mobility (Timed "Up & Go" test with preferred and non-preferred turns) and (4) physical and psychological impact of MS (MSIS-29 questionnaire). For (1) and (2), the stronger (SL) and the weaker leg (WL) were compared. After WBV, aROM (1) did not change (SL p = 0.26, WL p = 0.10), but was diminished after CON (SL -10% p = 0.06, WL -14% p = 0.03) with significant group differences (Δgroup WL p = 0.02). Motor accuracy in SL (2) was improved during dorsal flexion after WBV (p = 0.01, Δgroup p = 0.04) and deteriorated during plantar flexion after CON (p = 0.01, Δgroup p = 0.04). Additionally, participants (3) improved their functional mobility at the preferred turn (p = 0.04) and (4) ranked their quality of life higher solely after WBV (p = 0.05), without any differences between groups. However, values correlated significantly between angular precision and aROM as well as functional mobility. No further changes occurred. The results point towards an interception of degenerating mono-articular mobility and improvement of accuracy in the ankle joint. The motor effects after WBV are in line with enhanced perception of quality of life after six weeks which is why WBV could be a stimulus to enable greater overall autonomy in MS patients.

Modified defense reaction reduces biomechanical and myoelectrical ACL injury risk factors in elite Judo.

In judo, an anterior cruciate ligament (ACL) injury is the most severe injury an athlete could experience. Most ACL ruptures occur when defending against an osoto-gari attack. This study aims to identify ACL risk factors during osoto-gari defence and implement a modified osoto-gari defence reaction, which is assumed to improve myoelectric patterns and ameliorate critical biomechanical risk factors for ACL injuries. Twenty-six elite judokas were enrolled in the cross-over trial (female: 6; male: 20). 3D kinematics and force dynamometrics were combined with electromyographical recordings to assess the effects of the common and the modified osoto-gari defence reaction. Compared to the common osoto-gari defence reaction (maximal knee flexion: 29 ± 12°; maximal valgus: 10 ± 5°; maximal valgus moment: 58 ± 17 Nm; peak internal rotation: 9 ± 5°), the modified osoto-gari defence reaction showed significantly reduced knee angles (31 ± 10° p < 0.05; 1 ± 0° p < 0.05; 31 ± 9 Nm p < 0.05; 3 ± 0° p < 0.05). The myoelectric activity of the hamstring increased (+5±% to +27±%, p < 0.05) in the modified compared to common defence reaction. The modified osoto-gari defence reaction reduced critical biomechanical risk factors and increased hamstring myoelectric activity. We recommend the implementation of the modified osoto-gari defence reaction in judo practice and seek to evaluate its long-term effectiveness in decreasing ACL injury incidences in elite judo.

Depressive symptoms among Olympic athletes during the Covid-19 pandemic.

OBJECTIVES: The aim of this study was to analyze athlete-specific psychological strain among Olympic athletes following the postponement of the Tokyo 2020 Olympic games due to the COVID-19 pandemic. METHODS: A survey that comprised three sub-sections (Psychological Strain Questionnaire (APSQ), Patient Health Questionnaire-Depression Module (PHQ-8) and Participant characteristic) concerning mental health, performance issues and concerns about the postponement of the Tokyo Olympics, was distributed online and sent to 102 Olympic athletes. RESULTS: A total of 85 participants from 11 Olympic sports were enrolled. Results indicated that most athletes showed psychological strain related to concerns regarding the postponement of the Tokyo Olympics. Depression severity was positively associated with maladaptive avoidance coping patterns, negative effects in training, worries and fear. Depression severity was also negatively associated with motivation and adaptive factors such as chances and opportunities that can be drawn from the pandemic. CONCLUSION: The present sample of Olympic athletes reported suffering from psychological uncertainty associated with the postponement of the Olympic games. Sports federations should therefore, provide ongoing wellbeing support to athletes and offer them, for example, sports psychological support in order to be able to better deal with pandemic-related uncertainties and changes.

Prevalence of sport injuries in Olympic combat sports: a cross-sectional study examining one Olympic period.

BACKGROUND: Due to full contact impacts in combat sports, the risk of injuries is elevated. The aim of this study is to report severe injuries among athletes in Olympic combat sports. Specific injury types, time loss, and the performance level after injury are examined. METHODS: Survey to investigate injuries in Olympic combat sports during the time period from 2012-2016. Reported injuries were analyzed by anatomical location, injury type, gender, time loss, and performance level. RESULTS: The three injuries resulting in the longest time loss (ACL rupture: judo= 37 weeks; karate = 49 weeks; shoulder dislocation: wrestling = 41 weeks; shoulder rotator cuff injury: wrestling = 32 weeks) also accounted for the largest proportion of athletes with career-ending injuries (ACL rupture: judo = 28%; karate = 67%; shoulder dislocation: wrestling = 40%; shoulder rotator cuff injury: wrestling = 50%). Taekwondo and fencing had the shortest time loss (<12 weeks) among all combat sports. More injuries occurred during training (58%) as compared to competition (42%). Injury prevalence of competitive athletes was significantly higher as compared to recreational athletes. Male athletes suffered significantly more anterior cruciate ligament injuries (72% vs. 56%; P<0.05), unspecific shoulder injuries (89% vs. 47%; P<0.01), and elbow ligament injuries (57% vs. 30%; P<0.05) during training. CONCLUSIONS: The study shows that there are important differences between "punching and kicking" and "throwing" martial arts in terms of specific injury types. In judo and wrestling, the injuries are more likely to affect the joints (knee and shoulder). Therefore, injury prevention these sports should focus on strength training of the muscles surrounding the joints and on defensive reactionary movements to avoid dangerous biomechanical joint angles. In "punching and kicking" sports, injuries of the hands and feet, due to the large impact forces of strikes and kicks, could be reduced by improved protective equipment on hands and feet.

Epidemiology of injuries in track and field athletes: a cross-sectional study of specific injuries based on time loss and reduction in sporting level.

OBJECTIVES: To prevent the occurrence of injury in a sport, exact knowledge of injury patterns is needed. To synthesize sport-specific injuries in track and field comparing elite and recreational level athletes, as well as gender. Furthermore, analyze the time loss due to injury and reduction in athletic performance. METHODS: Injury type-specific frequencies were recorded according to discipline, gender and performance level. Injury severity was assessed by time loss duration and performance reduction. RESULTS: 64% of athletes suffered at least one injury. In the top 10 ranking, 83% (n = 524) were located in the lower extremities. A muscle strain of the thigh had the highest prevalence in sprint (34%, n = 41), jump (15%, n = 15) and middle-distance running (16%, n = 6). More injuries occurred during training (75%, n = 165) as compared to competition (25%, n = 56). The longest time loss was documented in throwing with a downtime of 36 weeks after a ligament injury of the elbow and 39 weeks after a muscle injury of the elbow. The injury with the highest number of athletes with a reduced level of performance was the foot ligament injury in sprint athletes at 100%. CONCLUSION: Assessing time loss and performance reduction in athletics, there are discipline-specific injury patterns. This study points out the high prevalence of training injuries, highlighting the need for future investigations to adapt training management, improve medical care and rehabilitation with respect to every discipline.