Exercise physiology and nutritional perspectives of elite soccer refereeing.

Referees are an integral part of soccer, and their performance is fundamental for regular match flow, irrespective of the competition level or age classes. So far, scientific interest was mainly limited to aspects of exercise physiology and match performance of soccer referees, whereas recommendations for nutrition were adopted from active professional soccer. In contrast to elite soccer players, most referees are non-professional and engaged in different occupations. Furthermore, elite referees and soccer players differ in regard to age, body composition, aerobic capacity, and training load. Thus, referees' caloric needs and recommended daily carbohydrate intake may generally be lower compared to active soccer players, with higher intakes limited to periods of increased training load and match days or for referees engaged in physical demanding occupations. With respect to fluid intake, pre-match and in-match hydration strategies generally valid in sports are recommended also for referees to avoid cognitive and physical performance loss, especially when officiating in extreme climates and altitude. In contrast to elite soccer, professional assistance concerning nutrition and training is rarely available for national elite referees of most countries. Therefore, special attention on education about adequate nutrition and fluid intake, about the dietary prevention of deficiencies (iron in female referees, vitamin D irrespective of sex and age), and basic precautions for travels abroad is warranted. In conclusion, the simple adoption of nutritional considerations from active soccer for referees may not be appropriate. Recommendations should respect gender differences, population-specific physical characteristics, and demands just as well as individual characteristics and special needs.

A new injury prevention programme for children's football--FIFA 11+ Kids--can improve motor performance: a cluster-randomised controlled trial.

The present study evaluated the effects of a newly developed injury prevention programme for children's football ("FIFA 11+ Kids") on motor performance in 7-12-year-old children. We stratified 12 football teams (under-9/-11/-13 age categories) into intervention (INT, N = 56 players) and control groups (CON, N = 67). INT conducted the 15-min warm-up programme "FIFA 11+ Kids" twice a week for 10 weeks. CON followed a standard warm-up (sham treatment). Pre- and post-tests were conducted using: single leg stance; Y-balance test; drop and countermovement jump; standing long jump; 20-m sprint; agility run; slalom dribble; and wall volley test. We used magnitude-based inferences and linear mixed-effects models to analyse performance test results. We observed likely beneficial effects favouring INT in Y-balance (right leg; +3.2%; standardised mean difference (SMD) = 0.34; P = 0.58) and agility run (+3.6%; SMD = 0.45; P = 0.008). Possibly beneficial effects were found in Y-balance, drop jump reactive strength index, drop jump height, countermovement jump, standing long jump, slalom dribble and wall volley test. At least possibly beneficial improvements in favour of "FIFA 11+ Kids" were observed in nearly all parameters. Most effects were small, but slight improvements in motor performance may potentially contribute to a reduction of injury risk.

Hip muscle weakness in patients with symptomatic femoroacetabular impingement.

OBJECTIVE: Femoroacetabular impingement (FAI) is a pathomechanical process, which may cause hip pain, disability and early development of hip osteoarthritis (OA) in young and active adults. Patients with FAI experience functional disability during dynamic weight-bearing activities, which could originate from weakness of the hip muscles. The objective of this study was to compare hip muscle strength between patients with symptomatic FAI and healthy controls. It was hypothesized that patients would present overall hip muscle weakness compared to controls. METHODS: A total of 22 FAI patients and 22 controls matched for gender, age, and body mass participated in the study. We evaluated isometric maximal voluntary contraction (MVC) strength of all hip muscle groups using hand-held and isokinetic dynamometry, and electromyographic (EMG) activity of the rectus femoris (RF) and tensor fasciae latae (TFL) muscles during active flexion of the hip. RESULTS: FAI patients had significantly lower MVC strength than controls for hip adduction (28%), flexion (26%), external rotation (18%) and abduction (11%). TFL EMG activity was significantly lower in FAI patients compared with controls (P=0.048), while RF EMG activity did not differ significantly between the two groups (P=0.056). CONCLUSIONS: Patients with symptomatic FAI presented muscle weakness for all hip muscle groups, except for internal rotators and extensors. Based on EMG recordings, it was demonstrated that patients with symptomatic FAI have a reduced ability to activate TFL muscle during hip flexion. These findings provide orthopedic surgeons with objective information about the amount and specificity of hip muscle weakness in patients with FAI. Future research should investigate the relationship between hip muscle weakness, functional disability and overuse injury risks, as well as the effects of hip muscle strengthening on clinical outcomes in individuals with symptomatic FAI.

Injuries of football referees: a representative survey of Swiss referees officiating at all levels of play.

The purpose of this study was to investigate the frequency and characteristics of injury and musculo-skeletal complaints in Swiss football referees of all levels. A representative sample of 489 Swiss referees was interviewed regarding their socio-demographic characteristics, refereeing qualifications, time spent in training and in matches, history of injuries and musculo-skeletal complaints caused by training or refereeing, and other medical problems. A total of 110 referees (22.5%) reported having suffered at least one injury related to officiating, and 126 referees (25.8%) at least one refereeing-related musculo-skeletal complaint. Thigh strains and ankle sprains were the most frequent injuries, with the most frequent locations of complaints being the knee and lower back. The incidence of match injuries in the last 12 months was on average 2.06 per 1000 match hours; the incidence of training injuries was substantially lower (0.09 per 1000 training hours). The injury rates were similar for referees officiating at an adult level, but lower at a junior level. In comparison with elite football referees, the incidence of training injuries and the prevalence of musculo-skeletal complaints were lower in amateur referees. Nevertheless, preventive programs are indicated for referees at all levels, especially when considering the length of a referee's career.

Female soccer referees selected for the FIFA Women's World Cup 2007: survey of injuries and musculoskeletal problems.

BACKGROUND: Few studies have examined the physiology, training and more recently injury profile of the soccer referee, and these have involved almost exclusively male referees. PURPOSE: To analyse the frequency and characteristics of injuries and musculoskeletal problems in female referees selected for the FIFA Women's World Cup 2007. STUDY DESIGN: Retrospective and prospective descriptive epidemiological study. METHODS: During the preparation camps a few months before the FIFA Women's World Cup 2007, all 81 preselected female referees completed a questionnaire on injuries and musculoskeletal problems. During the final 32 matches of the tournament in China, all injuries, musculoskeletal problems and related treatment of the 36 officiating referees were documented. RESULTS: Almost 50% of the referees reported having incurred at least one injury during their career that had led to time loss from the game. In the previous 12 months, 13 (16%) referees reported having sustained an injury and 64 (79%) reported musculoskeletal problems related to refereeing. During the World Cup and 14 (39%) referees incurred an injury and 17 (33%) were treated for musculoskeletal problems. The commonest location of injuries and problems were hamstrings, quadriceps, calf and ankle. The prospectively collected data found an incidence of 34.7 match injuries per 1000 match hours (95% CI 4.2 to 65.1). CONCLUSION: Top-level female referees are exposed to an even greater risk of injury and/or musculoskeletal problems related to officiating than are male referees. Considering the growth of women's soccer, injury prevention programmes should be specifically developed for female referees.

Injuries and musculoskeletal complaints in referees and assistant referees selected for the 2006 FIFA World Cup: retrospective and prospective survey.

BACKGROUND: There is a considerable amount of scientific literature on football, but few studies have focused on referees, despite their key role in this sport. Existing studies focus on the physiological demands and training of referees. PURPOSE: To analyse injuries and musculoskeletal complaints in referees and assistant referees selected for the 2006 FIFA World Cup. STUDY DESIGN: Retrospective survey and prospective study. METHODS: During the preparation camps for the 2006 FIFA World Cup in Germany, all 123 referees pre-selected for the tournament completed a questionnaire on injuries and musculoskeletal complaints. During the tournament, the characteristics and consequences of all injuries and complaints incurred by the 63 officiating referees were documented. RESULTS: More than 40% of the referees reported having incurred an injury and more than 60% having had musculoskeletal complaints during their career. About 20% of the group reported having suffered from musculoskeletal complaints in the last match. During the World Cup, 14 referees (22%) incurred an injury and more than 30% had musculoskeletal complaints. This prospectively collected data showed an incidence of 20.8 injuries per 1000 match hours (95% CI: 4.17 to 37.4). The most common acute injuries were hamstring strains, calf strains, and ankle sprains, while the most frequent locations of complaints were the low back, hamstring and knee. CONCLUSION: Considering the injury profile, the prevalence of associated musculoskeletal complaints, and the high physiological demands of refereeing, it appears that injury prevention programmes should be developed and integrated into the fitness training routine of the referee.

[Biomechanical issues in patellofemoral joint rehabilitation]. / Biomechanische Aspekte in der Rehabilitation des Patellofemoralgelenks.

Specific knowledge of the biomechanics of the patellofemoral joint is crucial for successful nonoperative or postsurgical rehabilitation. The biomechanical aspects of different situations should be considered when designing an exercise program. Joint reaction forces, contact area, and contact stress are dependent on flexion angle and exercise situations. In weight-bearing activities, the amount of knee flexion directly influences the magnitude of quadriceps muscle force, which affects the magnitude of patellofemoral joint reaction forces. Open and closed chain exercises should be performed within a safe range of motion to allow quadriceps activation while minimizing patellofemoral joint reaction forces. The isolated knee extension (90 degrees -40 degrees ), the squat (0 degrees -30 degrees -60 degrees ), and the leg press (0 degrees -30 degrees -60 degrees ) are the three main exercise situations in the acute rehabilitation phase. Controlled body positions and low levels of pain and symptoms should also be emphasized to achieve a functional progression, focusing on neuromuscular control.

Development of a German version of the knee outcome survey for daily activities.

INTRODUCTION: The knee outcome survey-activities of daily living scale (KOS-ADLS) is a patient-reported specific measure of knee function. The KOS-ADLS includes items related to both symptoms and functional limitations experienced during ADL. The purpose of this study was to examine the reliability and validity of a cross-culturally adapted German version of the KOS-ADLS. MATERIALS AND METHODS: 108 consecutive knee patients (n = 57 males/51 females) scheduled for outpatient physical therapy at an orthopedic hospital were enrolled in the investigation. For the reliability analysis, 50 patients were asked to complete the questionnaire on two non-consecutive days. To assess the validity of the KOS-ADLS, 58 additional patients answered the questionnaire in addition to performing a series of other related tests: (1) visual analogue scale for knee pain intensity, (2) The Get-up-and Go, and (3) time for ascending/descending stairs. The functional tests were selected because they directly related to specific items in the questionnaire and were thought to reflect the major areas of disability for this patient group. RESULTS: The reliability analysis demonstrated that the German version of the KOS-ADLS had a good reliability (ICC range 0.94-0.97) and internal consistency (alpha 0.89). The functional tests (e.g. Get-up and Go, ascending/descending stairs) showed moderate correlations, whereas the visual analogue pain scale was highly correlated with the subscores and total score of the KOS-ADLS. CONCLUSION: The psychometric characteristics of the German version of the KOS-ADLS produced reliable and valid results, as the original version, in detection of an individual's symptom and function related knee joint impairment.

[Rehabilitation guidelines after total knee arthroplasty]. / Rehabilitationsrichtlinien nach Knieendoprothesen.

Rehabilitation programs after total knee arthroplasty vary as much as do the surgical procedures employed. The postoperative range of motion of the knee is considered to be one of the primary indicators of the success of arthroplasty surgery. Protocols focusing on improving range of motion have been widely investigated: the end result does not seem to depend on using specific devices or exercises. There are no prospective randomized clinical trials evaluating the differences in outcome after total knee arthroplasty between patients following different rehabilitation programs. What are the needs of the patient after this surgery? Rehabilitation should focus on physical and functional limitations, and guidance of the patient during this process is important. The patient follows an individual program comprising a sensorimotor progression in weight-bearing positions to allow for improved functional knee stabilization. In knee osteoarthritis, and also after total knee arthroplasty, the neuromuscular system undergoes various adaptations during gait and other activities. Because of this, rehabilitation should not attempt to achieve hypothetical norms, but to help the patient in the motor learning process of acquiring improved motion patterns and stabilization strategies.