No relationship between the nordic hamstring and two different isometric strength tests to assess hamstring muscle strength in professional soccer players

ObjectivesTo investigate the relationship between one eccentric and two isometric tests commonly used to assess hamstring strength in professional soccer.SettingsProfessional soccer club.DesignCross-sectional study.ParticipantsTwenty male professional soccer players.Main outcome measuresHamstring force was quantified during 3 tests (Nordic hamstring eccentric, 90:20 isometric posterior-chain strength and isometric 15° knee flexion) using a load cell, a handheld dynamometer and a force platform, respectively.ResultsPoor relationships and low concordance were observed between isometric and eccentric tests, showing different ability to discriminate hamstring weakness and asymmetries. The Nordic hamstring test identified between-limb asymmetry >15% in 30% of the players, 25% in the 15° knee flexion and 5% in the 90:20 test. All players obtained different results in the three tests with only one showing asymmetry >15% in two tests.ConclusionResults obtained in each test cannot inform the others. Mechanical outputs of these tests must be used for particular purposes during the prevention, rehabilitation and monitoring process of hamstring injury. Isometric testing might be preferable during the initial phases of the recovery process of a hamstring injury while the Nordic hamstring test might be used in the last stages or detect muscle weakness/asymmetries in non-injured players.     

The influence of birth date and place of development on youth sport participation

Previous research highlights the critical role that contextual factors play in shaping athlete development. The purpose of the present study was to investigate two of these contextual factors: birth date (known as the relative age effect, RAE) and city of development as determinants of participation in a sample of youth ice hockey players. The sample included 146 424 athletes registered with Ontario youth ice hockey between the 2004 and 2010 seasons. Chi‐square statistics determined a significant RAE in youth ice hockey. Findings also revealed a significant association between small cities of development and increased youth ice hockey participation. Finally, there was no evidence of an interaction between relative age and city of development. The characteristics of smaller communities that may facilitate sport participation across all youth are discussed, along with recommendations for future research.     

Leaders promote attendance in sport and exercise sessions by fostering social identity

Sport and exercise participation exert a positive effect on numerous aspects of individuals' health. Although sport and exercise leaders have generally been observed to play a key role in shaping group members' behavior, our understanding of their impact on group members' attendance in sport and exercise sessions is limited. To address this, and building on promising findings in other domains, we examined the associations between perceptions of sport and exercise leaders' engagement in social identity leadership , group identification, and attendance. A sample of 583 participants from sports teams (n =  307) and exercise groups (n  =  276) completed questionnaires measuring identity leadership, group identification, and attendance. Analyses demonstrated that perceptions of leader engagement in social identity leadership were positively associated with members' group identification, and that this in turn was positively associated with their attendance in either a sports group or an exercise group. Moreover, there was a significant indirect effect for perceptions of leader engagement in identity leadership on group members' attendance through their greater identification with these groups. Findings highlight the importance of considering the impact sport and exercise leaders have on group members' attendance and suggest that leaders who represent, advance, create, and embed a shared sense of identity (ie, a shared sense of “us”) among attendees can promote participation in sport and exercise.     

Sport specialization and sport participation opportunities and their association with injury history in female high school volleyball athletes

ObjectiveDetermine the association of sport specialization in female volleyball athletes with previous injury history and determine the association of sport specialization with volleyball participation opportunities.DesignCross-sectional.SettingRecruitment occurred from 83 Wisconsin high schools during the 2018 volleyball season.ParticipantsFemale volleyball athletes (N = 1,588, grades 9–12, age = 15.6 ± 1.1 years).Main outcomesParticipants completed a pre-season questionnaire soliciting information regarding 1) demographics, 2) sport specialization, 3) sport participation, and 4) sport-related injuries in the previous 12 months. Univariable logistic regression models were used to identify associations with previous injury. Chi-square analyses were used to investigate associations between sport specialization classification and other sport participation opportunities.ResultsBoth moderately and highly specialized athletes were more likely to report a previous injury compared to low specialized athletes (moderate OR: 1.84 [1.29–2.62]; p < 0.001 and high OR: 2.30 [1.64–3.24]; p < 0.001). Highly specialized athletes were more likely to report participating in club volleyball, summer tournaments, and training camps in the past 12 months. Participants who reported participating in club volleyball, summer competitions, and training camps last year were more likely to report an injury.ConclusionsSpecialization was associated with injury history and year-round volleyball opportunities among female adolescent volleyball athletes.     

Sleep in Paralympic athletes and its relationship with injuries and illnesses

ObjectivesTo evaluate sleep characteristics and investigate the relationship of sleep with injuries and illnesses in Paralympic athletes.DesignCross-sectional.SettingSports Training Center.Participants20 Paralympic athletes of athletics, swimming, and powerlifting.OutcomesInjury and illnesses were recorded during the sports season through the Oslo Sports Trauma Research Center questionnaire (OSTRC-BR). Sleep-wake pattern was monitored for 2 weeks using actigraphy. Chronotype, sleep quality, sleep behavior, and sleep complaints were cross-sectionally collected.ResultsPoor sleep quality and poor sleep behavior were highly prevalent. The mean total sleep time was 6.57 ± 49.91. Duration of naps (r= −0.46; p=0.04) was associated with occurrence of health problems; frequency of insomnia (r= 0.51; p= 0.02), Pittsburgh Sleep Quality Index score (r= 0.45; p=0.04), and frequency of awakenings at night (r= 0.58; p= 0.01) were associated with severity of health problems; frequency of movements during sleep was associated with OSTRC-BR cumulative score (r= 0.58; p=0.00); and frequency of nightmares was associated with OSTRC mean score.ConclusionsParalympic athletes tend to report poor sleep quality, have poor sleep behavior and sleep less than the recommended. Insomnia symptoms, awakenings at night, movements during sleep and poor sleep quality were associated with the occurrence and/or severity of health problems.     

Return to sport and beyond following intramuscular tendon hamstring injury: A case report of an English Premier League football player

BackgroundHamstring strain injuries are the most common type of injury in elite football and are associated with a high risk of reinjury, particularly those involving the intramuscular tendon (IMT). Limited information is available regarding the rehabilitation and return to sport (RTS) processes following such injuries. This case study describes the clinical presentation of an elite football player following IMT hamstring injury, their on- and off-pitch rehabilitation alongside performance monitoring throughout RTS and beyond.Case scenarioAn elite football player suffered a grade 2c hamstring injury during an English Premier League (EPL) match. The player underwent early post-injury management, alongside progressive off-pitch physical preparation. The ‘control-chaos continuum’ was used as a framework for on-pitch rehabilitation to prepare the player for a return to full team training and competition. Objective and subjective markers of the player's response to progressive on- and off-pitch loading were monitored throughout RTS and beyond.OutcomesThe player returned to on-pitch rehabilitation after 11 days, to full team training having achieved weekly pre-injury chronic running load outputs after 35 days and played in the EPL 40 days post-injury. The player did not suffer reinjury for the rest of the EPL season.ConclusionAn understanding the unique structural and mechanical properties of the IMT, alongside expected RTS timeframes are important to inform rehabilitation and decision-making processes post-injury. Performance and frequent load-response monitoring throughout RTS and beyond, in conjunction with practitioner experience and effective communication are critical in facilitating effective RTS and reduce risk of reinjury following IMT injury.     

Specialization patterns across various youth sports and relationship to injury risk

Objectives: Current trends among young athletes towards earlier specialization age and year-round training on multiple teams has raised concern for increased injury risk. Our previous analyses showed higher risk for injury in highly specialized young athletes. The goal of this research was to determine whether sports specialization and injury patterns vary by sports type.

Methods: In this clinical case-control study, injured athletes (aged 7–18 years) were recruited from sports medicine clinics and compared to similarly aged uninjured athletes recruited from primary care clinics. Participants completed a survey reporting age, gender, sport type, specialization patterns, and details regarding sports-related injuries in the previous 6 months. Clinical diagnoses were collected from patients’ medical records. Injuries were classified as acute, overuse, or serious overuse.

Results: Of 1,190 athletes enrolled, 26% (313) were single-sport specialized (reported participation in one sport and trained >8 months/year). Sports with the highest proportion of single-sport specialized athletes were tennis (46.7%), gymnastics (30.1%), and dance (26.3%). Single-sport specialized athletes in individual sports started specializing at a younger age (11.2 ± 2.4 vs. 12.0 ± 2.7, p = 0.05) and reported higher training volumes (11.8 vs. 10.3 h/week, p = 0.04) than those in team sports. Sports with the youngest specialization age were gymnastics (8.9 ± 1.7), dance (10.8 ± 3.0), and soccer (10.9 ± 2.4). Single-sport specialized athletes in individual sports accounted for a higher proportion of overuse injuries (44.3% vs 32.2%, OR = 1.67, p = 0.037) and serious overuse injuries (23.4% vs 11.6%, OR = 2.38, p = 0.011), but a lower proportion of acute injuries (28.8% vs 13.8%, OR = 0.37, p = 0.001) compared to single-sport specialized athletes involved in team sports.

Conclusions: Athletes in individual sports may be more likely to specialize in a single sport than team sport athletes. Single-sport specialized athletes in individual sports also reported higher training volumes and greater rates of overuse injuries than single-sport specialized athletes in team sports.     

The relationship of superior labralanteroposterior (SLAP) lesions and pseudolaxity to shoulder injuries in the overhead athlete

Understanding the effect of superior labral lesions on the function of the shoulder is essential to successfullytreating the overhead athlete. Recognizing the pseudolaxity owing to superior labral anteroposterior (SLAP) lesions and the pathological "peel-back" sign is critical in evaluating the injured shoulder in general and repairing the SLAP lesion in particular. The mechanical characteristics of suture anchors are more favorable than tacks in resisting the pathological forces responsible for the peel-back mechanism. The higher success rate of arthroscopic suture anchor repair of SLAP lesions in comparison with open capsulolabral reconstruction suggests that SLAP lesions are the usual cause of the "dead arm" syndrome. In our experience, arthroscopic repair of SLAP lesions can return the overhead athlete to their preoperative level of function in the vast majority of cases (87% return to preoperative level for two or more seasons).     

Glenoid hypoplasia and its relationship to instability

 Glenoid hypoplasia, or dysplasia of the scapular neck, is usually a bilateral and symmetric finding. Associated findings include hypoplasia of the humeral head, elongation of the glenoid cavity, and alterations in the shape of the coracoid or clavicle. Glenoid hypoplasia has been reported sporadically in the radiologic literature, but the condition may be more frequent than previously thought. In this paper, we discuss the radiographic findings of glenoid hypoplasia and explore the possibility of an association between glenoid hypoplasia and shoulder instability.     

Association of sport participation in preterm and full term born children and body and fat mass indices from age 3 to 14 years

ObjectivesTo assess the association of gestational age groups (VP: <32 weeks, MP: 32–33 weeks, LP: 34–36 weeks and FT: ≥37 weeks of gestation) and club sport participation in childhood on body mass index (BMI), fat free mass index (FFMI) and fat mass index (FMI).DesignLongitudinal, cross sectional.MethodsBMI (age 3, 5, 7, 11 and 14 years; N = 10581–14702) and FFMI/FMI (age 7, 11 and 14 years; N = 10446–12996) and consistent club sport participation at age 5, 7 and 11 years (ranging from never participating to participating at all three ages) were assessed prospectively. These were compared by gestational age and their associations with BMI and FMI were investigated, while controlling for confounders (socio-economic, maternal obesity, child related, diet).ResultsBMI and FFMI was lower in VP or MP until age 7, but no differences were found in BMI, FFMI or FMI after age 11 with regard to gestational age. Consistent club sport participation from age 5–11 was unrelated to BMI at ages 3–7. However, FT children with club sport participation had lower BMI and FMI at ages 11 and 14; but this association was not found in VP or MP.ConclusionsDuring adolescence body composition of VP and MP become similar to FT born peers. Consistent sport participation reduces BMI and FMI in FT only. In VP or MP children modifying effects of sport on body composition might not be detected due to the catch-up growth in weight, height and fat mass at the same time.     

Perceived parental beliefs about the causes of success in sport: relationship to athletes' achievement goals and personal beliefs

This study examined the relationship between perceived parental beliefs and young athletes' achievement goal orientations and personal beliefs about the causes of success in sport. Participants were 183 male and female athletes, 11-18 years old, involved in team sports. Athletes completed the Task and Ego Orientation in Sport Questionnaire, the Beliefs about the Causes of Sport Success Questionnaire, and two modified versions of the latter inventory to assess their perceptions of their parents' beliefs. Canonical correlation analysis revealed that perceived parental beliefs were related to goal orientations and personal beliefs in a conceptually coherent fashion. Thus, the perceived parental belief that effort leads to success in sport was related to athletes' task orientation and personal belief that effort causes sport success. In contrast, the perceived parental beliefs that superior ability, external factors, and using deceptive tactics are precursors to success in sport corresponded to athletes' ego orientation and the same personal beliefs. The findings are discussed in terms of their implications for understanding the socialization experiences of young athletes.     

Seated limits‐of‐stability of athletes with disabilities with regard to competitive levels and sport classification

In this study, we asked whether wheelchair rugby (WR) classification and competitive level influence trunk function of athletes with disabilities, in terms of seated limits‐of‐stability (LoS). Twenty‐eight athletes were recruited from international‐ and national‐level WR teams, with each group exhibiting marked differences in years of sports practice and training volume. Athletes were also distributed into three groups according their classification: low‐point (0.5‐1.5‐point); mid‐point (2.0‐2.5‐point); and high‐point (3.0‐3.5‐point). Athletes were asked to sit on a force platform and to lean the body as far as possible in eight predefined directions. Center of pressure (COP) coordinates were calculated from the ground reaction forces acquired with the force platform. LoS were computed as the area of ellipse adjusted to maximal COP excursion achieved for the eight directions. ANOVAs reveal that LoS were not different when international‐ and national‐level players were compared (P=.744). Nevertheless, LoS were larger in players from the high‐point group than from the low‐point group (P=.028), with the mid‐point group being not different from both (P>.194). In summary, (i) competitive level does not impact LoS measures and (ii) LoS are remarkably distinct when comparing both extremes of the WR classification range. Our results suggest that, as a training‐resistant measure, LoS could be a valid assessment of trunk impairment, potentially contributing to the development of an evidence‐based WR classification.     

严重多发伤患者血浆凝血酶原片段1+2水平的变化及与弥散性血管内凝血的关系

目的 探讨严重多发伤患者血浆凝血酶原片段1＋2（F1＋2）水平变化及与创伤后弥散性血管内凝血（DIC）之间的关系。方法 将66例多发伤患者分为轻伤组（ISS评分〈16分,21例）和重伤组（ISS评分≥16分,45例）,再把重伤组分为并发DIC组（12例）与未并发DIC组（33例）,另10例健康人为正常对照组。射66例多发伤患者分别于伤后1、3、7天空腹采集外周静脉血,应用ELISA方法测定血浆F1＋2浓度。结果 轻伤组与重伤组血浆F1＋2水平伤后均明显高于正常对照组,且重伤组又明显高于轻伤组。非DIC组伤后F1＋2水平逐渐降低,DIC组伤后F1＋2水平持续升高,DIC组F1＋2水平显著高于非DIC组。结论 创伤后急性期F1＋2水平的升高程度不仅与创伤严重程度有关,而且与创伤后DIC的发生密切相关。因此,测定严重多发伤患者急性期外周血浆F1＋2水平变化对预测创伤后DIC的发生具有一定临床价值。     

Degenerative disease of the cervical spine and its relationship to athletes

Each sport presents with unique risk factors and different mechanisms of injury, and therefore extrapolation of the data from one sport to another makes comparison difficult. The current evidence exploring the relationship of athletes and degenerative changes of the cervical spine leaves much to be debated, and future prospective longitudinal studies will be needed to clarify our understanding further. Such research will help structure clinical recommendations and improve sports safety and the care of athletes of all ages. Currently, there is evidence to suggest that participation in collision sports is implicated in premature degeneration of the cervical spine. There is some evidence to suggest that the same is true with noncollision sports and activities that result in direct and indirect repetitive loads to the cervical spine over time. The risk factors have yet to be clearly identified. The natural history and sequelae of premature degeneration have yet to be elucidated. Cervical spondylosis also appears to increase the severity, but not the frequency, of irreversible neurologic injury during collision sport participation. Prudence dictates that we not ignore the present evidence suggesting a link between neuropraxia and cervical stenosis. Proper screening for cervical stenosis in patients with transient neuropraxia with subsequent cessation of participation in collision sports if severe stenosis is present is suggested. There is no consensus for RTP guidelines in the setting of transient neurologic injuries in the athlete when severe degeneration is present, and each case must be considered individually with regard to the sport involved.     

An intervention based on the health belief model led to improvements in self-efficacy towards ERIPP participation and functional performance in club sport athletes: a pilot study

ObjectivesTo determine if an intervention based on the Health Belief Model (HBM) could improve attitudes towards exercise-related injury prevention program (ERIPP) participation and functional performance in club sport participants.DesignRepeated measuresMethodsParticipants completed the HBM Scale (HBMS) and Theory of Planned Behavior Scale (TPBS) to assess attitudes towards ERIPP participation at three time points (pre-measure, post-measure, follow-up measure). The HBM based intervention was delivered immediately following the pre-measure containing: 1) education on ERIPPs, benefits and barriers to participating, strategies to overcome barriers, risk factors and consequences for lower extremity injuries, and strategies to prevent lower extremity injuries 2) individualized feedback on functional performance 3) demonstration and participation in the 11 + . Attitudes towards injury prevention were compared using the subscales of the HBMS and TPBS at all three time points. Functional performance was compared at the pre-measure and follow-up measure.ResultsSignificant improvements with large effect sizes were detected in individual self-efficacy from pre-test (0.73 ± 4.48) to post-test (2.93 ± 4.30; P = 0.05; ƞ2 = 0.18) and pre-test to follow-up (3.20 ± 3.49; P = 0.04; ƞ2 = 0.20) and community led self-efficacy from pre-test (4.40 ± 2.75) to post-test (6.07 ± 3.43; P = 0.02; ƞ2 = 0.24) and pre-test to follow-up (7.07 ± 2.05; P = 0.001; ƞ2 = 0.44). Additionally, significant improvements were found in the LESS-RT following the intervention.ConclusionsThe intervention based on the HBM led to improvements in individual and community led self-efficacy indicating an enhancement in the participants’ confidence in their ability to participate in an ERIPP. Future research should investigate the effectiveness of individualized interventions to improve attitudes towards and adherence to ERIPPs.