Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers

# Background Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance. # Purpose The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers. # Study Design Cross-sectional study (retrospective). # Methods Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO~2max~ testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history. # Results The breakers had a median 11.0 $$10.0 - 14.0$$ years breaking experience and trained 24.4 $$20.5 - 30.0$$ hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without. # Conclusion The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking. # Level of Evidence 2

Comparing Self-Reported Running Distance and Pace With a Commercial Fitness Watch Data: Reliability Study

BackgroundThere is substantial evidence exploring the reliability of running distance self-reporting and GPS wearable technology, but there are currently no studies investigating the reliability of participant self-reporting in comparison to GPS wearable technology. There is also a critical sports science and medical research gap due to a paucity of reliability studies assessing self-reported running pace. ObjectiveThe purpose of this study was to assess the reliability of weekly self-reported running distance and pace compared to a commercial GPS fitness watch, stratified by sex and age. These data will give clinicians and sports researchers insights into the reliability of runners’ self-reported pace, which may improve training designs and rehabilitation prescriptions. MethodsA prospective study of recreational runners was performed. Weekly running distance and average running pace were captured through self-report and a fitness watch. Baseline characteristics collected included age and sex. Intraclass correlational coefficients were calculated for weekly running distance and running pace for self-report and watch data. Bland-Altman plots assessed any systemic measurement error. Analyses were then stratified by sex and age. ResultsYounger runners reported improved weekly distance reliability (median 0.93, IQR 0.92-0.94). All ages demonstrated similar running pace reliability. Results exhibited no discernable systematic bias. ConclusionsWeekly self-report demonstrated good reliability for running distance and moderate reliability for running pace in comparison to the watch data. Similar reliability was observed for male and female participants. Younger runners demonstrated improved running distance reliability, but all age groups exhibited similar pace reliability. Running pace potentially should be monitored through technological means to increase precision

High Compliance with the 11+ Injury Prevention Program Results in Better Win-Loss Records

# Background The 11+ injury prevention program (IPP) has been shown to decrease injury rates. However, few studies have investigated compliance and its overall relationship to team performance. # Hypothesis/Purpose To examine if level of compliance while implementing the 11+ would impact team performance outcomes (wins, losses and ties). The authors hypothesized that higher team compliance to the IPP would be consistent with improved overall team performance (more wins and fewer losses). # Study Design Prospective, cluster randomized controlled trial # Methods This study was conducted in NCAA men's soccer teams for one season and examined the efficacy of the 11+ IPP. The outcome variables examined were levels of compliance and team performance record: wins, losses, and ties. Twenty-seven teams (n=675 players) served as the intervention group (IG) and used the 11+ program while 34 teams (n=850 players) served as the control group (CG). Compliance and team performance were recorded. There were three compliance categories that were defined prospectively, low (LC, \1 and \2 doses/week). Descriptive and inferential tests were used to compare the CG, the IG, and compliance to team performance. Three independent t-tests were used to analyze outcome to group (IG vs. CG). A one way-MANOVA test was used to analyze compliance to win/loss/tie record, followed up by one-way ANOVA tests to analyze how compliance impacted wins, losses and ties, independently. Partial η2 measures were calculated to determine the effect size of level of compliance on outcome. A Tukey post-hoc analysis was used to analyze specific differences between levels of compliance and specific outcome measures. # Results There were significantly more wins (IG: 10.67±2.63 versus CG: 8.15±3.83, CI, 7.95 -- 9.69, p = 0.005) and fewer losses (IG: 5.56±1.97 versus CG: 8.12±3.59, CI, 5.66 to 7.43, p = 0.002) recorded for the teams using the 11+ program. There was a statistically significant difference between levels of compliance (high, moderate or low) on the dependent variables (wins, losses, and ties), F(3, 22) = 3.780, p =0.004; Wilks' Λ = .435; partial η2 = .340. # Conclusion The 11+ has the capacity to improve overall team performance in male collegiate soccer teams. The higher the compliance, the more favorable the team performance. This research may be a vital addition when attempting to persuade coaching staffs to adopt an IPP into their training regimen. # Level of Evidence Level

Biomechanical Changes During a 90º Cut in Collegiate Female Soccer Players With Participation in the 11+

# Background Valgus collapse and high knee abduction moments have been identified as biomechanical risk factors for ACL injury. It is unknown if participation in the 11+, a previously established, dynamic warm-up that emphasizes biomechanical technique and reduces ACL injury rates, reduces components of valgus collapse during a 90º cut. # Hypothesis/Purpose To determine whether participation in the 11+ during a single soccer season reduced peak knee abduction moment and components of valgus collapse during a 90º cut in collegiate female soccer players. # Study Design Prospective cohort study # Methods Forty-six participants completed preseason and postseason motion analysis of a 90º cut. During the season, 31 players completed the 11+ and 15 players completed their typical warm-up (control group). Peak knee abduction moment, components of valgus collapse (hip adduction, internal rotation, and knee abduction angles), and a novel measure of knee valgus collapse were analyzed with repeated-measures ANOVAs to determine differences between preseason and postseason. Smallest detectable change (SDC) and minimal important difference (MID) values were applied to contextualize results. # Results There was a significant main effect of time for non-dominant knee valgus collapse (p=0.03), but decreases in non-dominant knee valgus collapse only exceeded the SDC in the intervention team. # Conclusions Clinically meaningful decreases in knee valgus collapse may indicate a beneficial biomechanical effect of the 11+. Participation in the 11+ may lower ACL injury risk by reducing valgus collapse during a 90º cut. # Level of Evidence 2

Return to performance following severe ankle, knee, and hip injuries in National Basketball Association players

Abstract The purpose of this study was to compare basketball performance markers one year prior to initial severe lower extremity injury, including ankle, knee, and hip injuries, to one- and two-years following injury during the regular NBA season. Publicly available data were extracted through a reproducible extraction computed programmed process. Eligible participants were NBA players with at least three seasons played between 2008 and 2019, with a time-loss injury reported during the study period. Basketball performance was evaluated for season minutes, points, and rebounds. Prevalence of return to performance and linear regressions were calculated. 285 athletes sustained a severe lower extremity injury. 196 (69%) played one year and 130 (45%) played two years following the injury. Time to return to sport was similar between groin/hip/thigh [227 (88)], knee [260 (160)], or ankle [260 (77)] (P = 0.289). 58 (30%) players participated in a similar number of games and 57 (29%) scored similar points one year following injury. 48 (37%) participated in a similar number of games and 55 (42%) scored a similar number of points two years following injury. Less than half of basketball players that suffered a severe lower extremity injury were participating at the NBA level two years following injury, with similar findings for groin/hip/thigh, knee, and ankle injuries. Less than half of players were performing at previous pre-injury levels two years following injury. Suffering a severe lower extremity injury may be a prognostic factor that can assist sports medicine professionals to educate and set performance expectations for NBA players

Keeping athletes on the field: an examination of primary and secondary ACL injury prevention outcomes

Snyder-Mackler, LynnIn its three aims this dissertation explored the outcomes of a primary prevention program, rehabilitation and return to sport after ACL reconstruction, and a secondary ACL injury prevention program. The FIFA11+ is a primary prevention program that reduces knee injuries in men’s collegiate soccer, however has not been examined in women’s collegiate soccer and it remains unknown if the program is effective in changing movement patterns associated with ACL injuries. In its first aim this dissertation established smallest detectable change and minimal important difference values for motion analysis of a drop jump. Then using these values to provide clinical context, this study found that although effective in reducing non-contact lower extremity injuries, the FIFA11+ did not reduce knee injuries or change biomechanical risk factors. In the second aim this dissertation explored if professional male athletes in Major League Soccer (MLS) after ACL reconstruction were at an increased risk for injuries, beyond their known increased risk for a new knee injury, and how returning to play after ACL reconstruction affected their career length. This study found that although not at an increased risk for lower extremity injury, MLS athletes had shorter careers compared to age matched controls. Seemingly these athletes made a return to sport but not a return to their preinjury level of performance. In its third aim this study explored the outcomes of the Anterior Cruciate Ligament-Specialized Post-Operative Return to Sports (ACL-SPORTS) program, a secondary prevention program designed to help bridge the gap between physical therapy discharge and return to sport. This study found that both men and women had increases in objective and self-reported outcome measures over the course of the training program, with the exception of quadriceps strength limb symmetry. Men had an increase in quadriceps strength limb symmetry with the program, where women’s strength symmetry remained the same. Further examination of the men found that 95% returned to their preinjury level of sport and only one had a second ACL injury (incidence 2.5%) in the two years following ACL reconstruction.Ph.D.University of Delaware, Biomechanics and Movement Science Program

Jumping performance based on duration of rehabilitation in female football players after anterior cruciate ligament reconstruction

Purpose To determine if female football players who had longer durations of rehabilitation, measured in months, after anterior cruciate ligament reconstruction would have lower tuck jump scores (fewer technique flaws) and smaller asymmetries during drop vertical jump landing. Methods One-hundred-and-seventeen female football players, aged 16ￜ25 years, after primary unilateral ACL reconstruction (median 16 months, range 6ￜ39) were included. Athletes reported the duration of rehabilitation they performed after anterior cruciate ligament reconstruction. Athletes also performed the tuck jump and drop vertical jump tests. Outcome variables were: tuck jump score, frontal plane knee motion and probability of peak knee abduction moment during drop vertical jump landing. Results There was no difference in tuck jump score based on duration of rehabilitation (n.s.). No interaction (n.s.), difference between limbs (n.s.), or duration of rehabilitation (n.s.) was found for peak knee abduction moment during drop vertical jump landing. No interaction (n.s.) or difference between limbs (n.s.) was found for frontal plane knee motion, but there was a difference based on duration of rehabilitation (P?=?0.01). Athletes with &gt;?9 months of rehabilitation had more frontal plane knee motion (medial knee displacement) than athletes with &lt;?6 months (P?=?0.01) or 6ￜ9 months (P?=?0.03). Conclusion As there was no difference in tuck jump score or peak knee abduction moment based on duration of rehabilitation, the results of this study press upon clinicians the importance of using objective measures to progress rehabilitation and clear athletes for return to sport, rather than time alone.Funding agencies: Swedish Research Council for Sport Science [CIF P2015-0150, FO2016-0021]; Futurum-the Academy for Healthcare, Region Jonkoping County; Medical Research Council of Southeast Sweden; Faculty of Health Sciences at Linkoping University; Swedish Football Assoc</p

Jump performance in male and female football players

Purpose To examine differences between men and women football players in clinically feasible jumping measures. Methods Female football players (N=46, ages 16-25) were matched based on age, training frequency, and playing position with 46 male players. All players performed the tuck jump and drop vertical jump (DVJ). DVJ was assessed quantitatively for valgus knee motion and probability of a high peak knee abduction moment (pKAM), as well as sagittal plane hip, knee, and ankle angles, and qualitatively with visual assessment of the players knees upon landing; graded as good, reduced, or poor control. Result Women had higher total tuck jump scores (52) (more technique flaws), than men (3 +/- 2, Pamp;lt;0.01). The quantitative analysis of the DVJ found that men had greater asymmetries between limbs, but women landed bilaterally in more knee valgus (interaction P=0.04, main effect of sex P=0.02). There was no difference in pKAM (interaction n.s.). Women also landed in less hip flexion (P=0.01) and ankle dorsiflexion (P=0.01) than men. The qualitative DVJ analysis found that more women (48%) had poor knee control compared to men (11%, Pamp;lt;0.01). Conclusions The results indicate that women perform worse on the tuck jump assessment than men. The results support previous findings that women land in more knee valgus than men, but also found that men may have larger asymmetries in knee valgus. These results from clinically feasible measures provide some suggestions for clinicians to consider during ACL reconstruction rehabilitation to enhance performance.Funding Agencies|Linkoping University</p

A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

ABSTRACTInjuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health

ACL injury prevention: Where have we come from and where are we going?

Anterior cruciate ligament (ACL) injuries are one of the most common and severe knee injuries across sports. As such, ACL injury prevention has been a focus of research and sports medicine practice for the past three‐plus decades. Examining the current research and identifying both clinical strategies and research gaps, the aim of this review is to empower clinicians and researchers with knowledge of where the ACL injury prevention literature is currently and where it is going in the future. This paper examines the mechanism of ACL injury prevention, screening, implementation, compliance, adherence, coronavirus, and areas of future research. Clinical significance: The time lag between research and practical implementation in general healthcare settings can be as long as 17 years; however, athletes playing sports today are unable to wait that long. With effective programs already established, implementation and adherence to these programs is essential. Strategies such as coaching education, increasing awareness of free programs, identifying barriers, and overcoming implementation obstacles through creative collaboration are just a few ways that could help improve both ACL injury prevention implementation and adherence