What biomechanical parameters are related to drag-flick performance in field hockey? A systematic review.

The drag-flick is a highly relevant skill to enlarge scoring opportunities during penalty corners in field hockey. Understanding drag-flick biomechanics will likely assist in optimising training and performance of drag-flickers. The purpose of this study was to identify the biomechanical parameters related to drag-flicking performance. Five electronic databases were systematically searched from inception to 10 February 2022. Studies were included if quantified biomechanical parameters of the drag-flick were assessed and related to performance outcomes. Quality assessment of the studies was performed according to the Joanna Briggs Institute critical appraisal checklist. Study type, study design, participants' characteristics, biomechanical parameters, measurement instrumentation and results were extracted from all included studies. The search yielded 16 eligible studies (142 drag-flickers). Many different single kinematic parameters were associated with drag-flick performance and related to biomechanical aspects described in this study. Nonetheless, this review identified a lack of a solid body of knowledge on this topic due to a low number of studies as well as low study quality and strength of evidence. Future high-quality research is needed to develop a clear biomechanical blueprint of the drag-flick to better understand this complex motor skill.

Validity of a New 3-D Motion Analysis Tool for the Assessment of Knee, Hip and Spine Joint Angles during the Single Leg Squat.

AIM: Study concurrent validity of a new sensor-based 3D motion capture (MoCap) tool to register knee, hip and spine joint angles during the single leg squat. DESIGN: Cross-sectional. SETTING: University laboratory. PARTICIPANTS: Forty-four physically active (Tegner ≥ 5) subjects (age 22.8 (±3.3)) Main outcome measures: Sagittal and frontal plane trunk, hip and knee angles at peak knee flexion. The sensor-based system consisted of 4 active (triaxial accelerometric, gyroscopic and geomagnetic) sensors wirelessly connected with an iPad. A conventional passive tracking 3D MoCap (OptiTrack) system served as gold standard. RESULTS: All sagittal plane measurement correlations observed were very strong for the knee and hip (r = 0.929-0.988, p < 0.001). For sagittal plane spine assessment, the correlations were moderate (r = 0.708-0.728, p < 0.001). Frontal plane measurement correlations were moderate in size for the hip (ρ = 0.646-0.818, p < 0.001) and spine (ρ = 0.613-0.827, p < 0.001). CONCLUSIONS: The 3-D MoCap tool has good to excellent criterion validity for sagittal and frontal plane angles occurring in the knee, hip and spine during the single leg squat. This allows bringing this type of easily accessible MoCap technology outside laboratory settings.

Manual therapy and early return to sport in football players with adductor-related groin pain: A prospective case series.

OBJECTIVES: To study the clinical course including return to sport success rates of football players with adductor-related groin pain (ARGP) after manual therapy of the adductor muscles. DESIGN: Prospective case series. METHODS: Thirty-four football players with ARGP with median pre-injury Tegner scores of 9 (IQR 25-75: 9-9) were treated with manual therapy of the adductor muscles. Main outcome measures were numeric pain rating scale (NPRS), Hip and Groin Outcome Score (HAGOS) and global perceived effect (GPE) for treatment and patient satisfaction at 2, 6 and 12 weeks. Return to sport was documented. RESULTS: Pain during (NPRS 7 (6-8) and after (NPRS 8 (6-8) sports decreased to NPRS 1 (0.2-3) and 1 (0.8-3), respectively (p < 0.001). Within 2 weeks 82% of the players returned to pre-injury playing levels with improved (p < 0.001) HAGOS subscale scores. Eighty-five percent reported clinically relevant improvement, 82% reported to be satisfied. At 12 weeks, 88% had returned to pre-injury playing levels. HAGOS showed symptoms were still present. CONCLUSION: Early return to sport seems possible and safe after manual therapy of the adductor muscles in football players with ARGP in the short term. While the majority of injured football players return to sport within two weeks, caution is advised regarding effectiveness as hip and groin symptoms were still present and no control groups were available.

Including performance level lowers prevalence of non-timeloss groin injury. A cross-sectional study in 383 female amateur football players.

OBJECTIVE: To study the preseason prevalence of groin injury with normal and reduced performance. DESIGN: Cross-sectional cohort. SETTINGS: Online survey. PARTICIPANTS: 383 Dutch female amateur football players (35 teams). MAIN OUTCOME MEASURES: Prevalence of groin injury per injury group (timeloss or non-timeloss) using a general questionnaire and per performance group (groin pain with normal or reduced performance) using subscales Pain and Participation in Physical Activities of the Hip And Groin Outcome Score (HAGOS). Levels and between-group differences of groin-related symptoms and problems (HAGOS) for injury and performance groups. The injury groups from which players with groin pain and normal performance originate. RESULTS: Prevalence of non-timeloss groin injury was 22% (95% confidence interval (95%CI) = 18-26) (n = 84), 7% (95%CI = 5-10) (n = 26) for timeloss groin injury, 21% (95%CI = 17-25) (n = 80) for pain + normal performance and 16% (95%CI = 12-20) (n = 61) for pain + reduced performance. HAGOS-scores differed between injury (P < .022) and performance groups (p < .043). Twenty-three players (27%) with pain + normal performance originated from the non-timeloss groin injury group (100%). CONCLUSION: As female amateur football players with groin pain and normal performance are considered non-injured, the prevalence of non-timeloss groin injury lowers by a quarter. These players have lower HAGOS scores than non-injured players without pain yet higher scores than those with non-timeloss groin injury.

The effect of compression shorts on pain and performance in male football players with groin pain - A double blinded randomized controlled trial.

OBJECTIVE: To investigate the effects of compression shorts on pain and performance in football players with groin pain. STUDY DESIGN: Double blinded randomized controlled trial. SETTING: Soccer pitch. PARTICIPANTS: Thirty-four male football players with groin pain. MAIN OUTCOME MEASURES: The effect of wearing zoned high compression shorts (ZHC-shorts), non-zoned low compression shorts (NZLC-shorts), and normal sports clothes on pain measured with the Numeric Pain Rating Scale (NPRS) and performance during the Copenhagen 5-s squeeze test (CS), the Illinois Agility test (IAT), and maximum shooting (ST). The effects of wearing ZHC versus NZLC shorts on symptoms were measured using the Hip and groin outcome score (HAGOS) during actual football activities. RESULTS: Wearing ZHC-shorts reduced pain during the IAT (1.4, ES = 0.58, p= <0.01) and ST (1.2, ES = 0.47, p= <0.01) compared to wearing normal sports clothes, but did not negatively affect performance. Compared to the baseline HAGOS scores a clinically significant improvement in the symptoms (9.7, ES = 0.63, p= <0.01) and sport/recreation (13.2, ES = 0.68, p = 0.01) subscales was found when wearing the ZHC-short during football activities. CONCLUSION: Wearing zoned high compression shorts could be useful in reducing groin pain in football players during their football activities.

Hip and groin injury is the most common non-time-loss injury in female amateur football.

PURPOSE: Hip and groin injuries in football are problematic due to their high incidence and risk of chronicity and recurrence. The use of only time-loss injury definitions may underestimate the burden of hip and groin injuries. Little is known about hip and groin injury epidemiology in female football. The first aim of this study was to examine the within-season (2014-2015) prevalence of total injury with and without time-loss in female amateur football players. The second aim was to study the within-season and preseason (2015-2016) prevalence of hip/groin injuries with and without time-loss. The third aim was to study the association between the duration of hip and groin injury in the 2014-2015 season and the severity of hip/groin problems during the 2015-2016 preseason. METHODS: During the preseason, 434 Dutch female amateur football players completed an online questionnaire based on the previous season and current preseason. The hip and groin outcome score (HAGOS) was used to assess the severity of hip and groin injuries. RESULTS: The hip/groin (17%), knee (14%), and ankle (12%) were the most frequent non-time-loss injury locations. The ankle (22%), knee (18%), hamstring (11%), thigh (10%), and hip/groin (9%) were the most common time-loss injury locations. The previous season prevalence of total injury was 93%, of which non-time-loss injury was 63% and time-loss injury was 37%. The prevalence of hip/groin injury was 40%, non-time-loss hip/groin injury was 36% and time-loss hip/groin injury was 11%. The preseason prevalence of hip/groin injury was 27%, non-time-loss hip/groin injury was 25%, and time-loss hip/groin injury was 4%. Players with longstanding hip/groin injury (> 28 days) in the previous season had lower HAGOS scores at the next preseason than players with short-term (1-7 days) or no hip/groin injury (p < 0.001). From all players with hip/groin injury from the previous season, 52% also sustained hip/groin injury in the following preseason, of which 73% were recurrent and 27% were chronic hip/groin injuries. CONCLUSION: Injury risk, and especially non-time-loss hip and groin injury risk, is high in female amateur football. Three-quarters of the players with longstanding hip and groin injuries in the previous season have residual problems at the start of the following season. LEVEL OF EVIDENCE: II.

Risk Factors for Groin Injury and Groin Symptoms in Elite-Level Soccer Players: A Cohort Study in the Dutch Professional Leagues.

Background Groin injury and groin symptoms are common in soccer players. The relationship of groin injury and groin symptoms to reduced hip range of motion (ROM) and previous injury is unclear. Objectives To conduct a retrospective assessment of associations between previous injury and preseason hip ROM and preseason prevalence of severe groin symptoms, and to prospectively identify risk factors for within-season groin injury. Methods During the period of 2015 to 2016, 190 players from 9 Dutch professional soccer clubs participated in this cohort study with prospective and retrospective elements. Univariate and multivariate logistic regressions were used to predict preseason severe groin symptoms, identified using the Copenhagen Hip and Groin Outcome Score, from a history of previous groin injury, general injury (minimum of 1 week in duration) in the previous season, and hip ROM. Cox regression was used to predict within-season groin injury. Results Point prevalence of severe groin symptoms was 24% and within-season incidence of groin injury was 11%. Total, training, and match groin injury incidences were 0.5, 0.2, and 2.6 injuries per 1000 playing hours, respectively. A history of more than 1 previous groin injury was associated with current severe groin symptoms (odds ratio = 3.0; 95% confidence interval: 1.0, 8.3; P = .038). General injury sustained in the previous season (ankle, knee, thigh, shoulder; median, 9 weeks of time loss) was a risk factor for groin injury (hazard ratio = 5.1; 95% confidence interval: 1.8, 14.6; P = .003). Conclusion Severe injuries in the previous season to locations other than the groin increase the risk of groin injury the next season. A history of groin injury is associated with current severe groin symptoms. Preseason hip ROM does not identify players at risk for groin injury. Level of Evidence Prevention, level 2b. J Orthop Sports Phys Ther 2018;48(9):704-712. Epub 23 May 2018. doi:10.2519/jospt.2018.7990.

Is lower hip range of motion a risk factor for groin pain in athletes? A systematic review with clinical applications.

BACKGROUND: Whether hip range of motion (ROM) is a risk factor for groin pain in athletes is not known. OBJECTIVES: To systematically review the relationship between hip ROM and groin pain in athletes in cross-sectional/case-control and prospective studies. STUDY DESIGN: Systematic review, prospectively registered (PROSPERO) according to PRISMA guidelines. METHODS: Pubmed, Embase, CINAHL and SPORTDiscus were systematically searched up to December 2015. Two authors performed study selection, data extraction/analysis, quality assessment (Critical Appraisal Skills Programme) and strength of evidence synthesis. RESULTS: We identified seven prospective and four case-control studies. The total quality score ranged from 29% to 92%. Heterogeneity in groin pain classification, injury definitions and physical assessment precluded data pooling. There was strong evidence that total rotation of both hips below 85° measured at the pre-season screening was a risk factor for groin pain development. Strong evidence suggested that internal rotation, abduction and extension were not associated with the risk or presence of groin pain. CONCLUSION: Total hip ROM is the factor most consistently related to groin pain in athletes. Screening for hip ROM is unlikely to correctly identify an athlete at risk of developing groin pain because of the small ROM differences found and poor ROM measurement properties.

Range of motion of body segments is larger during the maximal instep kick than during the submaximal kick in experienced football players.

BACKGROUND: Football players with groin injury refrain from maximal kicking. Previous groin injury is related to decreased hip range of motion (ROM). Information on ROM differences between maximal and submaximal kicking within players is lacking. The first aim of this study is to quantify ROM of body segments during the maximal (MaxK) and submaximal (SubK) instep kick at four key points. The second aim is to study ROM differences of tension arc and movement trajectories between MaxK and SubK. METHODS: Maximal (100% ball speed) and submaximal (70% ball speed) instep kicks from 15 experienced football players were registered with motion capture. ROM of hip, spine, pelvis and knee segments were determined at four key points. Differences in segmental ROM for the tension arc and movement trajectories between MaxK and SubK were studied. Effect sizes (ES) were calculated. RESULTS: Ball speed was 98.8±9.0 km/h for MaxK and 69.5±7.1 km/h for SubK. Three key points timed similarly (P<0.05) for MaxK and SubK. MaxK shows increased ROM for all segments (P<0.05) but not for hip flexion. MaxK results in enlargement of tension arc and movement trajectories. Spine flexion (ES=3.2) and pelvis posterior tilt (ES=2.2) show the greatest relative increase. CONCLUSIONS: Maximal kicking shows larger segmental ROM than submaximal kicking. Enlargement of tension arc and movement trajectories relate to increased segmental velocity, according to biomechanical concepts. Central body actions play an important role in kicking. This information can be used to further identify kicking strategies in athletes with injury.

Hip Range of Motion Is Lower in Professional Soccer Players With Hip and Groin Symptoms or Previous Injuries, Independent of Cam Deformities.

BACKGROUND: Soccer (football) players often have hip and groin symptoms (HGS), and a previous groin injury is a risk factor for a relapse. Decreased hip range of motion (HROM) has been related to both hip and groin pain and the presence of a cam deformity. How these factors interact is unknown. PURPOSE: The first aim was to study whether HGS are associated with HROM. The second aim was to study the association of the presence of a cam deformity with HROM. Additionally, the influence of a cam deformity on the relationship between HGS and HROM was examined. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Seasonal screening data of 2 professional soccer clubs were used. Variables for HGS were current hip or groin pain, the Copenhagen Hip and Groin Outcome Score (HAGOS), and previous hip- and groin-related time-loss injuries (HGTIs). HROM was determined for hip internal rotation (IR), external rotation, and total rotation (TR) in the supine position and for the bent knee fall out (BKFO) test. A cam deformity was defined by an alpha angle >60° on standardized anteroposterior pelvic and frog-leg lateral radiographs. RESULTS: Sixty players (mean [±SD] age, 23.1 ± 4.2 years) were included. All were noninjured at the time of screening. Current hip or groin pain was not associated with HROM. Hips of players in the lowest HAGOS interquartile range (thus most affected by complaints; n = 12) showed less IR (23.9° ± 8.7° vs 28.9° ± 7.8°, respectively; P = .036) and TR (58.2° ± 13.5° vs 65.6° ± 11.8°, respectively; P = .047) than those in the highest interquartile range (n = 29). No such differences were found for BKFO (P = .417). Hips of players with a previous HGTI showed less IR (21.1° ± 6.8° vs 28.3° ± 8.9°, respectively; P < .001) and TR (56.0° ± 8.2° vs 64.5° ± 13.6°, respectively; P < .001) than those without a previous HGTI. This was independent of the presence of a cam deformity. BKFO did not differ between groups (P = .983). Hips with a cam deformity showed less but nonsignificant IR (25.5° ± 10.3° vs 29.0° ± 7.1°, respectively; P = .066) and TR (P = .062) and higher but nonsignificant BKFO values (17.1 cm ± 3.4 cm vs 14.2 cm ± 4.6 cm, respectively; P = .078) than those without a cam deformity. CONCLUSION: Decreased HROM in professional soccer players is associated with more hip- and groin-related symptoms and with previous injuries, independent of the presence of a cam deformity.

Timing characteristics of body segments during the maximal instep kick in experienced football players.

BACKGROUND: The first aim of this study was to describe duration and relative timing of the phases of the maximal instep kick. The second aim was to describe the concurrence of maximal range of motion, maximal angular acceleration, maximal angular deceleration and maximal angular velocity of body segments with four key points. METHODS: Twenty experienced football players performed three maximal instep kicks. The kicks were analysed using a full body, three-dimensional motion capture system. Camera recordings determined kicking leg events. The concurrence of peak kinematics of body segments with four key points was calculated. RESULTS: Duration and timing of five phases were identified. Key point maximal hip extension (51.4±5.0%) concurred significantly with maximal range of motion (ROM) of shoulder extension. Key point maximal knee flexion (63.6±5.2%) concurred significantly with maximal angular acceleration of spine flexion and pelvis posterior tilt. Key point knee flexion 90 degrees (69.3±4.9%) concurred significantly with maximal angular velocity of shoulder flexion and spine flexion, maximal angular deceleration of hip flexion and maximal angular acceleration of knee extension. Key point ball impact (75.2±5.2%) concurred significantly with maximal ROM of hip deflexion and pelvis anterior rotation and with maximal angular deceleration of spine flexion and pelvis anterior rotation. CONCLUSIONS: This study demonstrated that eleven peak kinematics of upper body and kicking leg segments, significantly concurred with four kicking leg positions. These results provide Key points for kicking coordination and stress the importance of dynamical coupling as a kicking mechanism.

The relationship between the frequency of football practice during skeletal growth and the presence of a cam deformity in adult elite football players.

BACKGROUND/AIM: Cam deformity (CD) is likely a bony adaptation in response to high-impact sports practice during skeletal growth. We ascertained whether a dose-response relationship exists between the frequency of football practice during skeletal growth and the presence of a CD in adulthood, and if the age at which a football player starts playing football is associated with the presence of a CD in adulthood. METHODS: Prevalence of a CD (α angle>60°) and a pathological CD (α angle>78°) was studied using standardised anteroposterior (AP) and frog-leg lateral (FLL) radiographs that were obtained during seasonal screening. The age of starting to play football with a low frequency (LF; ≤3 times/week) and high frequency (HF; ≥4 times/week) was retrospectively assessed. The differences in prevalence of a CD per hip, in either view, between groups were calculated by logistic regression with generalised estimating equations. RESULTS: 63 players (mean(±SD) age 23.1(±4.2) years) participated, yielding 126 hips for analysis. The prevalence of a CD in the FLL was 40% (n=82) in players who started playing HF football from the age of 12 years or above, and 64% (n=44) in those playing HF football before the age of 12 years (p=0.042). This was also true for a pathological CD (12% vs 30%, p=0.038). The AP views revealed no difference. CONCLUSIONS: Our results indicate a probable dose-response relationship between the frequency of football practice during skeletal growth and the development of a CD, which should be confirmed in future prospective studies.