OBJECTIVE: The association between groin pain and range of motion is poorly understood. The aim of this study was to develop a test to measure sport specific range of motion (SSROM) of the lower limb, to evaluate its reliability and describe findings in non-injured (NI) and injured football players.DESIGN: Case-controlled.SETTING: 6 Dutch elite clubs, 6 amateur clubs and a sports medicine practice.PARTICIPANTS: 103 NI elite and 83 NI amateurs and 57 football players with unilateral adductor-related groin pain.MAIN OUTCOME MEASURES: Sport specific hip extension, adduction, abduction, internal and external rotation of both legs were examined with inclinometers. Test-retest reliability (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Non-injured players were compared with the injured group.RESULTS: Intra and inter tester ICCs were acceptable and ranged from 0.90 to 0.98 and 0.50-0.88. SEM ranged from 1.3 to 9.2° and MDC from 3.7 to 25.6° for single directions and total SSROM. Both non-injured elite and amateur players had very similar total SSROM in non-dominant and dominant legs (188-190, SD ± 25). Injured players had significant (p < 0.05) total SSROM deficits with 187(SD ± 31)° on the healthy and 135(SD ± 29)° on the injured side.CONCLUSION: The SSROM test shows acceptable reliability. Loss of SSROM is found on the injured side in football players with unilateral adductor-related groin pain. Whether this is the cause or effect of groin pain cannot be stated due to the study design. Whether restoration of SSROM in injured players leads to improved outcomes should be investigated in new studies.
Blog post where the author speaks about his recently published article "Adherence to an injury prevention program in male amateur football players is affected by players’ age, experience and perceptions"
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In foul decision-making by football referees, visual search is important for gathering task-specific information to determine whether a foul has occurred. Yet, little is known about the visual search behaviours underpinning excellent on-field decisions. The aim of this study was to examine the on-field visual search behaviour of elite and sub-elite football referees when calling a foul during a match. In doing so, we have also compared the accuracy and gaze behaviour for correct and incorrect calls. Elite and sub-elite referees (elite: N = 5, Mage ± SD = 29.8 ± 4.7yrs, Mexperience ± SD = 14.8 ± 3.7yrs; sub-elite: N = 9, Mage ± SD = 23.1 ± 1.6yrs, Mexperience ± SD = 8.4 ± 1.8yrs) officiated an actual football game while wearing a mobile eye-tracker, with on-field visual search behaviour compared between skill levels when calling a foul (Nelite = 66; Nsub−elite = 92). Results revealed that elite referees relied on a higher search rate (more fixations of shorter duration) compared to sub-elites, but with no differences in where they allocated their gaze, indicating that elites searched faster but did not necessarily direct gaze towards different locations. Correct decisions were associated with higher gaze entropy (i.e. less structure). In relying on more structured gaze patterns when making incorrect decisions, referees may fail to pick-up information specific to the foul situation. Referee development programmes might benefit by challenging the speed of information pickup but by avoiding pre-determined gaze patterns to improve the interpretation of fouls and increase the decision-making performance of referees.
