Spikes in acute:chronic workload ratio (ACWR) associated with a 5-7 times greater injury rate in English Premier League football players: a comprehensive 3-year study.

OBJECTIVES: We examined the relation between global positioning system (GPS)-derived workloads and injury in English Premier League football players (n=33) over three seasons. METHODS: Workload and injury data were collected over three consecutive seasons. Cumulative (1-weekly, 2-weekly, 3-weekly and 4-weekly) loads in addition to acute:chronic workload ratios (ACWR) (acute workload (1-week workload)) divided by chronic workload (previous 4-week average acute workload) were classified into discrete ranges by z-scores. Relative risk (RR) for each range was then calculated between injured and non-injured players using specific GPS variables: total distance, low-intensity distance, high-speed running distance, sprint distance, accelerations and decelerations. RESULTS: The greatest non-contact injury risk was when the chronic exposure to decelerations was low (<1731) and the ACWR was >2.0 (RR=6.7). Non-contact injury risk was also 5-6 times higher for accelerations and low-intensity distance when the chronic workloads were categorised as low and the ACWR was >2.0 (RR=5.4-6.6), compared with ACWRs below this. When all chronic workloads were included, an ACWR >2.0 was associated with a significant but lesser injury risk for the same metrics, plus total distance (RR=3.7-3.9). CONCLUSIONS: We recommend that practitioners involved in planning training for performance and injury prevention monitor the ACWR, increase chronic exposure to load and avoid spikes that approach or exceed 2.0.

Physiotherapist-led treatment for young to middle-aged active adults with hip-related pain: consensus recommendations from the International Hip-related Pain Research Network, Zurich 2018.

The 1st International Hip-related Pain Research Network meeting discussed four prioritised themes concerning hip-related pain in young to middle-aged adults: (1) diagnosis and classification of hip-related pain; (2) patient-reported outcome measures for hip-related pain; (3) measurement of physical capacity for hip-related pain; (4) physiotherapist-led treatment for hip-related pain. Thirty-eight expert researchers and clinicians working in the field of hip-related pain attended the meeting. This manuscript relates to the theme of physiotherapist-led treatments for hip-related pain. A systematic review on the efficacy of physiotherapist-led interventions for hip-related pain (published separately) was conducted and found that strong evidence for physiotherapist-led treatments was lacking. Prior to the meeting, draft consensus recommendations for consideration in the meeting were also developed based on the systematic review. The draft consensus recommendations were presented to all of the meeting participants via email, at least 1 week prior to the meeting. At the meeting, these recommendations were discussed, revised and voted on. Six recommendations for clinical practice and five recommendations for research were included and all gained consensus. Recommendations for clinical practice were that (i) Exercise-based treatments are recommended for people with hip-related pain. (ii) Exercise-based treatment should be at least 3 months duration. (iii) Physiotherapist-led rehabilitation after hip surgery should be undertaken. (iv) Patient-reported outcome measures, measures of physical impairment and measures of psychosocial factors should be used to monitor response to treatment. (v) Physical activity (that may include sport) is recommended for people with hip-related pain. (vi) Clinicians should discuss patient expectations, use shared-decision making and provide education. Recommendations for research were (i) Reporting of exercise programmes: Exercise descriptors such as load magnitude, number of repetitions and sets, duration of whole programme, duration of contractile element of exercise, duration of one repetition, time under tension, rest between repetitions, range of motion through which the exercise is performed, and rest between exercise sessions should be reported. (ii) Research should investigate the optimal frequency, intensity, time, type, volume and progression of exercise therapy. (iii) Research should examine the effect of patient education in people with hip-related pain. (iv) Research should investigate the effect of other treatments used in people with hip-related pain (for example: manual therapy, medications, injections). (v) Research should examine the impact of comorbidities and social determinants on treatment effectiveness in people with hip-related pain. Clinicians and researchers working with young to middle-aged active adults with hip-related pain may use these consensus recommendations to guide, develop, test and implement individualised, evidence-based physiotherapist-led rehabilitation programmes.

Physical activity during adolescence and the development of cam morphology: a cross-sectional cohort study of 210 individuals.

INTRODUCTION: Cam morphology is a strong risk factor for the development of hip pain and osteoarthritis. It is increasingly thought to develop in association with intense physical activity during youth; however, the aetiology remains uncertain. The study aim was to characterise the effect of physical activity on morphological hip development during adolescence. METHODS: Cross-sectional study of individuals aged 9-18 years recruited from Southampton Football Club Academy (103 male) with an age-matched control population (52 males and 55 females). Assessments included questionnaires and 3 Tesla MRI of both hips. Alpha angle, epiphyseal extension and epiphyseal tilt were measured on radial images. RESULTS: Alpha angle and epiphyseal extension increased most rapidly between ages 12 and 14 years. Soft-tissue hypertrophy at the femoral head-neck junction preceded osseous cam morphology and was first evident at age 10 years. The greatest increase and highest absolute values of alpha angle and epiphyseal extension were colocalised at 1 o'clock. Maximum alpha angles were 6.7 degrees greater in males than females (p=0.005). Compared with individuals who play no regular sport, alpha angles were 4.0 degrees higher in individuals who play sport for a school or club (p=0.041) and 7.7 degrees higher in individuals competing at a national or international level (p=0.035). There was no association with leg dominance . CONCLUSIONS: Sporting activity during adolescence is strongly associated with the development of cam morphology secondary to epiphyseal hypertrophy and extension with a dose-response relationship. Males participating in competitive sport are at particularly elevated risk of developing cam morphology and secondary hip pathology.

Accumulated workloads and the acute:chronic workload ratio relate to injury risk in elite youth football players.

AIM: The purpose of this study was to investigate the relationship between physical workload and injury risk in elite youth football players. METHODS: The workload data and injury incidence of 32 players were monitored throughout 2 seasons. Multiple regression was used to compare cumulative (1, 2, 3 and 4-weekly) loads and acute:chronic (A:C) workload ratios (acute workload divided by chronic workload) between injured and non-injured players for specific GPS and accelerometer-derived variables:total distance (TD), high-speed distance (HSD), accelerations (ACC) and total load. Workloads were classified into discrete ranges by z-scores and the relative risk was determined. RESULTS: A very high number of ACC (≥9254) over 3 weeks was associated with the highest significant overall (relative risk (RR)=3.84) and non-contact injury risk (RR=5.11). Non-contact injury risk was significantly increased when a high acute HSD was combined with low chronic HSD (RR=2.55), but not with high chronic HSD (RR=0.47). Contact injury risk was greatest when A:C TD and ACC ratios were very high (1.76 and 1.77, respectively) (RR=4.98). CONCLUSIONS: In general, higher accumulated and acute workloads were associated with a greater injury risk. However, progressive increases in chronic workload may develop the players' physical tolerance to higher acute loads and resilience to injury risk.

Coronal-plane leg alignment in adolescence and the effects of activity: A full leg length MRI study.

The aim of this study was to explore the association between developing coronal-plane leg alignment and activity levels during adolescence. We performed a cross-sectional cohort study with individuals from soccer club academies and an age-matched control population. Outcome measures were the hip knee angle (HKA), medial proximal tibial physeal angle (MPTPhyA), lateral distal femoral physeal angle (LDFPhyA) on full leg length magnetic reasonance imagine scans, and the physical activity questionnaire (PAQ) score. The cohort comprised 57 elite male soccer players, 34 male and 34 female controls aged 11-21 years. Mean HKA became more varus with age, with little change after 16 years or skeletal maturity. Skeletally mature elite male soccer players were significantly more varus than male controls with a HKA 2.28° less than male controls (p < 0.001). Skeletally mature male controls had a HKA 1.34° less than female controls (p < 0.001). A negative correlation existed between HKA and PAQ score (coefficient -0.24, p = 0.029). A positive correlation existed between HKA and MPTPhyA (coefficient 0.32, p = 0.008). In conclusion, high activity levels during adolescence are associated with the development of varus leg alignment. Mean HKA becomes more varus with age until skeletal maturity. The development of varus alignment may represent a physiological adaptation to load at the proximal tibial physis. Clinical Significance: A time period may exist for intervention before the development of varus leg alignment in young athletes, such as training load modification or proximal tibial morphology monitoring.

Measuring 3D growth plate shape: Methodology and application to cam morphology.

Physeal changes corresponding to cam morphology are currently measured using two-dimensional (2D) methods. These methods are limited by definitions of the femoral neck axis and head center that are dependent on the radiographic plane of view. To address these limitations, we developed three-dimensional (3D) methods for analyzing continuous growth plate shape using magnetic resonance imaging scans. These new methods rely on a single definition of the femoral neck axis and head center that are both nondependent on the radiographic plane of view and allow for analysis of growth plate shape across the growth plate surface (performed using statistical parametric mapping). Using our 3D method, we analyzed the position of the growth plate in the femoral head (relative to a plane tangent to the femoral head) and the curvature of the growth plate (relative to a plane through the center of the growth plate) in 9-16-year-old males at risk for cam morphology and their recreationally active peers (n = 17/cohort). These two measurements provide an avenue to separately analyze the effects of these variables in the overall growth plate shape. We detected differences in growth plate shape with age in recreationally active adolescents but did not detect differences between at risk and recreationally adolescents.

A longitudinal cohort study of adolescent elite footballers and controls investigating the development of cam morphology.

Cam morphology describes an asphericity of the femoral head that develops during adolescence, is highly prevalent in athletes, and predisposes individuals to future osteoarthritis. However, it's aetiology remains poorly understood. The aim of this study was to perform 3-year longitudinal follow-up of a control population and football club academy cohort to compare the change in hip and growth plate anatomy between athletes and controls. MRI and questionnaires were used to characterise change in hip and growth plate anatomy and quantify activity levels. 121 male academy footballers and 107 male and female controls participated at baseline. Footballers experienced significantly greater increases in femoral head asphericity (4.83 degrees (95% CI: 2.84 to 6.82), p < 0.001) than controls. A positive correlation existed between activity levels and change in femoral head morphology (coefficient 0.79, p ≤ 0.001). Greatest morphological change occurred in individuals aged 11-12 years at baseline, with no significant change in individuals aged 14 years and older at baseline. Cam morphology development was secondary to soft tissue hypertrophy and lateral growth plate extension. In conclusion, excessive loading of the hip joint through exercise prior to 14 years of age may result in growth plate adaptations causing cam morphology. Potential interventions may include training type and load modification in young adolescent football players.