Peak torque angle, acceleration time and time to peak torque as additional parameters extracted from isokinetic test in professional soccer players: a cross-sectional study

This study investigated additional and traditional variables from isokinetic test of thigh muscles in soccer players across different field positions. One hundred and eighty-nine athletes performed maximal concentric isokinetic knee contractions on dominant (DL) and non-dominant limb (NDL) at 60º/s and 240º/s. The additional outcomes peak torque angle (AngPT), acceleration time (AcT) and time to peak torque (TPT) and traditional outcomes Peak torque (PT), total work (TW) and power (Pw) were extracted from the exam. Goalkeepers (GK), side backs (SB), central backs (CB), central defender midfielders (CDM), central attacking midfielders (CAM) and forwards (FW) were considered. Comparisons between limbs and positions demonstrated that SB extensors of the DL presented TPT lower (p = 0.006) and AngPT higher (p = 0.011) than NDL at 60°/s. CDM extensors of the DL showed lower TPT at 60°/s (p = 0.003) and 240°/s (p = 0.024). CAM flexors of the DL showed lower TPT (p = 0.026) and AcT (p = 0.021) at 240°/s than NDL. CB, CDM and CAM extensors of the NDL showed higher PT, TW and Pw than DL (p < 0.05). In conclusion, there are muscle imbalances between limbs in SB, CDM and CAM and across different field positions.

Differences in Neurocognitive Functions Between Healthy Controls and Anterior Cruciate Ligament-Reconstructed Male Athletes Who Passed or Failed Return to Sport Criteria: A Preliminary Study

BACKGROUND

Only 55% of anterior cruciate ligament-reconstructed (ACLR) athletes return to competitive sports. This brings into question the usefulness of current return to sport (RTS) criteria. High cognitive demand of sport environment clarifies the value of incorporating neurocognitive tests when making decisions regarding the time of RTS. This preliminary study aimed to compare the neurocognitive functions between healthy controls and ACLR male athletes who passed or failed RTS criteria.

METHODS

A total of 45 male football players, including 15 ACLR who passed RTS criteria, 15 ACLR who did not pass, and 15 healthy controls participated in this cross-sectional study. The Cambridge Neuropsychological Test Automated Battery was used to measure a battery of neurocognitive tasks, including speed of response, sustained attention, working memory, cognitive flexibility, and response inhibition.

RESULTS

The results revealed that compared with both the ACLR-passed and healthy groups, the ACLR-failed group showed greater values of 5-choice movement time (P = .02, P = .01, respectively) but lower values of stop signal reaction time (P = .03, P = .001, respectively) and proportion of successful stops variables (P = .02). In addition, compared with the healthy group, both the ACLR-failed and ACLR-passed groups indicated greater values in between errors (P < .001, P = .008, respectively) and reaction latency variables (P = .002, P = .01, respectively) but lower values of A' (P < .001, P = .007, respectively), probability of hit (P < .001, P = .03, respectively), and percent correct trials variables (P = .006, P = .02, respectively).

CONCLUSIONS

Our findings indicated deficits in neurocognitive functions in ACLR male athletes. In addition, poor performance in sustained attention, working memory, and cognitive flexibility measures observed in the ACLR-passed group highlighted the necessity for using a multimodal approach via implementation of neurocognitive measures in conjunction with the functional and muscular assessments when making RTS decisions.

Epidemiology of injuries in elite male and female futsal: a systematic review and meta-analysis

The main purpose of this study was to conduct a systematic review and meta-analysis quantifying the incidence of injuries in futsal players. A systematic search was conducted using MEDLINE, PubMed, Web of Science and Scopus databases and subsequently, six studies (14 cohorts) were selected. Separate meta-analyses for male and female players were conducted using a Poisson random-effect regression model approach. The overall and match incidence rates in elite male futsal players were 6.8 (95% CI = 0.0-15.2) and 44.9 (95% CI = 17.2-72.6) injuries/1000 hours of exposure. Pooled training injury rate in male players was not calculated due to the lack of studies reporting training injuries in this cohort. For females, an overall, training and match incidence rates of 5.3 (95% CI = 3.5-7), 5.1 (95% CI = 2.7-7.6) and 10.3 (95% CI = 0.6-20.1) injuries/1000 hours of exposure were reported. In males, match incidence rate in International tournaments was 8.5 times higher than in national leagues (77.2 [95% CI = 60.0-94.5] vs 9.1 [95% CI = 0.0-19.3] for international tournaments and national leagues, respectively). Elite male and female futsal players are exposed to a substantial risk of sustaining injuries, especially during matches.

Methodological Proposal for Strength and Power Training in Older Athletes: A Narrative Review

INTRODUCTION

Within the adult population, it is not uncommon to meet older athletes who challenge the negative stereotypes associated with aging. Although their physical performance is superior to their sedentary counterparts, they are not immune to impaired neuromuscular function, leading to a decreased physical capacity and an increased risk of injuries. Despite the abundant information about the benefits of strength/power training in advanced ages, there are no methodological proposals that guide physical activity professionals to program this type of training.

OBJECTIVE

This study aimed to review the factors related to the decrease in sports performance within older athletes and the benefits of a strength/power program in order to provide a methodological proposal to organize training in this population.

METHODS

This is a review article. First, databases from PubMed, Science Direct, and SPORTSDiscus and search engines, namely Google Scholar and Scielo, were reviewed, using standard keywords such as strength and power training, evaluation of physical performance, neuromuscular function, and risk of injury in the elderly athlete. All related articles published during the period 1963 to 2020 were considered. A total of 1837 documents were found. By removing 1715 unrelated documents, 122 articles were included in the study after revision control.

RESULTS

Strength/power training is key to alleviating the loss of performance in older athletes and the benefits in neuromuscular function, which helps reduce the rate of serious injuries, maintaining sports practice for a longer period of time. In order to design an appropriate program, a prior evaluation of the individual's physical-technical level must be carried out, respecting the biologicalpedagogical principles and safety regulations.

CONCLUSION

The methodological proposal delivered in this review can serve as a technical guide for physical activity professionals, which will be able to structure the strength/power training and thus preserve the sports practice in older athletes for a longer time.

Comparison of Knee and Hip Kinematics during Landing and Cutting between Elite Male Football and Futsal Players

To design an accurate sport injury prevention program, alterations in the knee and hip kinematic variables involved in injury mechanisms should be known. The main purpose of the current study was to compare knee and hip kinematic variables during landing and cutting among male football and futsal players, and to discuss them within an injury description frame. Twenty football (20.5 ± 2.1 years., 74.5 ± 6.9 kg and 1.79 ± 0.07 m) and twenty futsal players (20.3 ± 2.0 years., 73.5 ± 7.1 kg and 1.78 ± 0.07 m), with at least three years’ experience of playing in the Kerman Province League, participated in this study. Hip flexion, knee flexion and knee valgus angle during two main movements with risk of injury, such as landing and cutting, were measured using a motion capture system with passive markers at 120-Hz sampling frequency. Landing and cutting maneuvers were administered in as natural way as possible. Results showed significant differences in landing and cutting maneuvers between groups in hip flexion, knee flexion and knee valgus angle. Results indicated that footballers have less extension of hip and knee joints than futsal players in landing maneuvers, which may be due to the higher requirement of jumping−landing maneuvers when playing football. In cutting maneuvers, footballers showed less hip and knee flexion than futsal players, whereas the knee valgus angle in cutting maneuvers was lower in futsal players. More information on the injury mechanisms of landing and cutting in football and futsal are needed to improve the design of injury prevention programs.

Risk of Injury in Moral Dilemmas With Autonomous Vehicles

As autonomous machines, such as automated vehicles (AVs) and robots, become pervasive in society, they will inevitably face moral dilemmas where they must make decisions that risk injuring humans. However, prior research has framed these dilemmas in starkly simple terms, i.e., framing decisions as life and death and neglecting the influence of risk of injury to the involved parties on the outcome. Here, we focus on this gap and present experimental work that systematically studies the effect of risk of injury on the decisions people make in these dilemmas. In four experiments, participants were asked to program their AVs to either save five pedestrians, which we refer to as the utilitarian choice, or save the driver, which we refer to as the nonutilitarian choice. The results indicate that most participants made the utilitarian choice but that this choice was moderated in important ways by perceived risk to the driver and risk to the pedestrians. As a second contribution, we demonstrate the value of formulating AV moral dilemmas in a game-theoretic framework that considers the possible influence of others’ behavior. In the fourth experiment, we show that participants were more (less) likely to make the utilitarian choice, the more utilitarian (nonutilitarian) other drivers behaved; furthermore, unlike the game-theoretic prediction that decision-makers inevitably converge to nonutilitarianism, we found significant evidence of utilitarianism. We discuss theoretical implications for our understanding of human decision-making in moral dilemmas and practical guidelines for the design of autonomous machines that solve these dilemmas while, at the same time, being likely to be adopted in practice.

Smartphone-Based Answering to School Subject Questions Alters Gait in Young Digital Natives

Smartphone texting while walking is a very common activity among people of different ages, with the so-called "digital natives" being the category most used to interacting with an electronic device during daily activities, mostly for texting purposes. Previous studies have shown how the concurrency of a smartphone-related task and walking can result in a worsening of stability and an increased risk of injuries for adults; an investigation of whether this effect can be identified also in people of a younger age can improve our understanding of the risks associated with this common activity. In this study, we recruited 29 young adolescents (12 ± 1 years) to test whether walking with a smartphone increases fall and injuries risk, and to quantify this effect. To do so, participants were asked to walk along a walkway, with and without the concurrent writing task on a smartphone; several different parameters linked to stability and risk of fall measures were then calculated from an inertial measurement unit and compared between conditions. Smartphone use determined a reduction of spatio-temporal parameters, including step length (from 0.64 ± 0.08 to 0.55 ± 0.06 m) and gait speed (1.23 ± 0.16 to 0.90 ± 0.16 m/s), and a general worsening of selected indicators of gait stability. This was found to be mostly independent from experience or frequency of use, suggesting that the presence of smartphone activities while walking may determine an increased risk of injury or falls also for a population that grew up being used to this concurrency.

Risk of Injury in Physically Active Students: Associated Factors and Quality of Life Aspects

Background: The aim of this study was to assess the potential factors of hypermobility and pain threshold on the risk of injury in physically active students and to verify which domains of quality of life are rated lower by young people with a history of injuries. Methods: The study included 278 students (138 women and 140 men) who regularly undertake physical activity. Anthropometric measurements, body composition, pain threshold, incidence of hypermobility syndrome, information on the history of injuries to the locomotor system, and the quality of life of the study participants were collected. Results: In the group studied, hypermobility and pain threshold had a statistically significant related on the risk of injury. Participants with a history of injuries had lower scores for an individual’s overall perception of their own health and the physical domain. There were also significant differences in the psychological domain of the quality of life between males and females with a history of injuries. Conclusion: In the studied group, the risk of injuries was related to diagnosed hypermobility and pain threshold measured on the lower limbs. The study also showed that people with a history of injuries had statistically significantly lower scores in the individual general perception of their own health and in the physical domain. Gender had a significant impact on the quality of life of people with injuries.

Humeral Torsion as a Risk Factor for Shoulder and Elbow Injury in Professional Baseball Pitchers

BACKGROUND

Numerous studies have demonstrated that humeral retrotorsion is increased in the dominant arms of throwing athletes. No study has clearly defined the relationship between humeral retrotorsion and shoulder and elbow injury.

HYPOTHESIS

Uninjured professional pitchers will display more dominant humeral torsion (HT) than professional pitchers who sustain shoulder injuries but less than pitchers who sustain elbow injuries.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Pitchers from the Colorado Rockies professional baseball organization were recruited for participation for this prospective injury study from 2009 to 2013. HT was assessed using indirect ultrasonographic techniques and was measured prospectively in 255 pitchers before each spring training (average of 2 trials). From the beginning of the preseason to the end of the postseason, overuse upper extremity injuries (shoulder or elbow) were tracked for each participating athlete. All athletes who reported pain or injury to their coach were referred to the organization's athletic trainer for evaluation and classification of each injury. The difference in HT was calculated by subtracting measurement of the dominant arm from the nondominant arm, and 3 separate mixed-model analyses of variance (side × injury group) were used to compare the dominant and nondominant HT between all pitchers who developed an arm injury (shoulder and elbow combined), as well as comparing pitchers who developed a shoulder or elbow injury to those who did not miss games due to shoulder or elbow injury (α = .05).

RESULTS

During the course of the study, 60 arm (30 shoulder; 30 elbow) injuries were observed; 195 pitchers did not suffer an injury. There were no differences when HT was compared between all injured (shoulder and elbow injuries combined) and uninjured pitchers (P = .13; effect size 0.14). There was a significant interaction effect showing that pitchers who suffered a shoulder injury displayed 4° less dominant humeral retrotorsion compared with pitchers without injury (P = .04) and that pitchers with elbow injury displayed 5° greater humeral retrotorsion (P = .04). In addition, those who suffered an ulnar collateral ligament injury requiring reconstruction (n = 17) also displayed 4(o) greater dominant retrotorsion and 5° less nondominant humeral retrotorsion compared with pitchers who did not suffer an injury (n = 195; P = .05). There was not a significant difference between nondominant HT among pitchers who sustained shoulder and elbow injuries and pitchers without injury.

CONCLUSION

The results of this study show a contrast in dominant humeral retrotorsion between pitchers who suffered shoulder and elbow injuries compared with those without an injury. Pitchers who sustained shoulder injuries had less dominant humeral retrotorsion compared with noninjured pitchers. In contrast, pitchers who sustained time-loss elbow injuries displayed increased humeral retrotorsion compared with noninjured pitchers. Together, these results suggest that increased adaptive humeral retrotorsion is protective against shoulder injuries but a harmful contributor for elbow injuries in professional pitchers. This is the first study to show differing injury risk profiles for shoulder and elbow injury.

The effects of military body armour on the lower back and knee mechanics during box drop and prone to standing tasks

Modern day body armour (BA) has been successful at increasing survivability from previously lethal explosives; however, it has been suggested to reduce warfighter's performance and increase risk of injury. Joint biomechanics have a foremost impact on performance and risk of injury. The immediate and prolonged effects of wearing BA on biomechanics of the lower back and knee during box drop (BD) and prone to standing tasks were investigated. The immediate effects of BA on both tasks were an increase of ≥4% (p ≤ 0.02) in temporal task durations and a decrease of ~1.66 N/kg (p = 0.03) in normalised peak ground reaction force for the BD test. The prolonged duration of walking with BA (i.e. 45 min) was not found to cause more changes in our measures than walking without BA. Quantitative data related to the effects of BA are important for risk assessment and mission design such to reduce the risk of injury without compromising performance. Practitioner Summary: The effects of wearing military body armour (BA) on biomechanics of the lower back and knee were investigated. Though wearing BA was found to affect some biomechanical measures related to performance, the prolonged effects of exposure on our measures were the same whether or not the participants wore BA.

Home-Based Direct Care Workers: Their Reported Injuries and Perceived Training Knowledge

The objectives of the study were to profile occupational injury patterns across home health and hospice care (HHC), organization characteristics, and home health aides' (HHAs) individual characteristics, and examine how worker training affects HHAs' risk of reporting an injury using the model of human factors of health care in the home. The authors measured training knowledge using an 11-item scale and conducted univariate and bivariate analyses to describe injury patterns across individual, occupational, and organizational factors using STATA 12.0. The researchers found that work-related injuries and type of injury were associated with increased likelihood of reporting one or more injuries, full-time employment, high hourly pay, and working in an inpatient or mixed setting. Overall, HHAs perceived that they received "excellent" and "good" training on key topics that promoted safety and job knowledge. Furthermore, the results suggested linkages between worker's complex personal, occupational, and organizational characteristics.

Ability of preseason body composition and physical fitness to predict the risk of injury in male collegiate hockey players

Background:

Injuries in collegiate ice hockey can result in significant time lost from play. The identification of modifiable risk factors relating to a player’s physical fitness allows the development of focused training and injury prevention programs targeted at reducing these risks.

Purpose:

To determine the ability of preseason fitness outcomes to predict in-season on-ice injury in male collegiate ice hockey players.

Study Design:

Prognostic cohort study.

Level of Evidence:

Level 3.

Methods:

Athlete demographics, percentage body fat, aerobic capacity (300-m shuttle run; 1-, 1.5-, 5-mile run), and strength assessment (sit-ups, push-ups, grip strength, bench press, Olympic cleans, squats) data were collected at the beginning of 8 successive seasons for 1 male collegiate ice hockey team. Hockey-related injury data and player-level practice/game athlete exposure (AE) data were also prospectively collected. Seventy-nine players participated (203 player-years). Injury was defined as any event that resulted in the athlete being unable to participate in 1 or more practices or games following the event. Multivariable logistic regression was performed to determine the ability of the independent variables to predict the occurrence of on-ice injury.

Results:

There were 132 injuries (mean, 16.5 per year) in 55 athletes. The overall injury rate was 4.4 injuries per 1000 AEs. Forwards suffered 68% of the injuries. Seventy percent of injuries occurred during games with equal distribution between the 3 periods. The mean number of days lost due to injury was 7.8 ± 13.8 (range, 1-127 days). The most common mechanism of injury was contact with another player (54%). The odds of injury in a forward was 1.9 times (95% CI, 1.1-3.4) that of a defenseman and 3 times (95% CI, 1.2-7.7) that of a goalie. The odds of injury if the player’s body mass index (BMI) was ≥25 kg/m² was 2.1 times (95% CI, 1.1-3.8) that of a player with a BMI <25 kg/m². The odds ratios for bench press, maximum sit-ups, and Olympic cleans were statistically significant but close to 1.0, and therefore the clinical relevance is unknown.

Conclusion:

Forwards have higher odds of injury relative to other player positions. BMI was predictive of on-ice injury. Aerobic fitness and maximum strength outcomes were not strongly predictive of on-ice injury.

The effects of military body armour on the lower back and knee mechanics during toe-touch and two-legged squat tasks

While effective in the prevention of otherwise lethal injuries, military body armour (BA) has been suggested to reduce warfighter's performance and increase injury-related musculoskeletal conditions. Providing the significant role of joint biomechanics in both performance and risk of injury, the immediate and prolonged effects of wearing BA on biomechanics of the lower back and knee during toe-touch (TT) and two-legged squat (TLS) tasks were investigated. The immediate effects of BA were an increase of >40 ms (p ≤ 0.02) in flexion duration of the dominant joint and an ∼1 s (p ≤ 0.02) increase in overall task duration as well as an ∼18% (p = 0.03) decrease in the lumbopelvic rhythm ratio near the mid-range of trunk flexion. In general the prolonged duration of wearing BA (i.e. 45 min of walking) was not found to cause more changes in our measures than walking without BA.

PRACTITIONER SUMMARY

The effects of wearing military BA on biomechanics of the lower back and knee during TT and TLS tasks were investigated. The immediate effects of BA were increased flexion duration, increased overall trial duration and decreased lumbopelvic rhythm near the mid-range of trunk flexion.

Balance training exercises decrease lower-limb strength asymmetry in young tennis players

The issue of functional asymmetries in the lower-limbs has been the subject of numerous recent investigations concerning many different contact, limited-contact and non-contact sports. The presence of strength asymmetries in the lower-limbs of young athletes practicing various sporting disciplines is considered an intrinsic risk factor for injury; in such cases, compensation strategies should thus be implemented aimed at eliminating, or at least limiting, the degree of asymmetry in order to avoid the negative consequences asymmetries can have upon the health of young sportsmen and women on the long-term. The aim of the present study was to examine the presence of functional asymmetries in the lower-limbs of young tennis players in strength and speed drill performance and to test a specific balance-training programme in its capacity to effectively reduce such asymmetries. Twenty-three young tennis players were randomly assigned to the Experimental Group (EG) (n = 11: 4 females, 7 males; 13.2 ± 0.9 years; 50.8 ± 8.9 Kg; 1.63 ± 0.08 m) or Comparison Group (CG) (n = 12: 4 females, 8 males; 13.0 ± 0.9 years; 51.1 ± 9.2 Kg; 1.61 ± 0.09 m). To quantify percent asymmetries in lower-limb strength before (T0) and following (T1) training, performances were assessed in the one-leg hop test (OLH), side-hop test (SH) and side steps and forward 4.115-m test (4m-SSF). Performances in the 10 and 20m sprint tests and the Foran test were also assessed. The EG completed a total of 12 training sessions directed at balance training: two 30-minute sessions/week over a 6-week period. The CG followed an identical training schedule, but training sessions consisted of tennis-specific drills only. The results reveal significant differences between pre- and post-training tests in the EG only: the degree of lower-limb asymmetry was decreased in the EG following completion of the training programme, as assessed using the OLH test (p < 0.001), SH test (p < 0.001) and 4m-SSF test (p < 0.05). A significant interaction and main effect of training was also observed in the EG: balance training led to a significant reduction in the percent of asymmetry in lower-limb strength, as measured using the SH (p < 0.01), 4m-SSF (p < 0.01) and OLH (p < 0.05) tests. These results confirm that balance training exercises are able to counteract/reduce the degree of asymmetry in lower-limb strength in young tennis players. Key pointsThe determination of functional asymmetries in the lower-limbs has been the subject of numerous recent investigations aimed at the prevention of injuries in many different contact, limited-contact and non-contact sports.Sport-specific movements in tennis impose different loads upon the two lower-limbs and can cause the development of lower-limb strength asymmetries in young tennis players.The planning of athletic conditioning in young tennis players requires that strength in the lower-limbs is evaluated such that appropriate injury prevention strategies may be inserted into training programmes.Balance training exercises, and indeed all tasks performed on unstable surfaces, lead to benefits in sport-specific performance.