Background In clinical practice range of motion (RoM) is usually assessed with low-cost devices such as a tape measure (TM) or a digital inclinometer (DI). However, the intra- and inter-rater reliability of typical RoM tests differ, which impairs the evaluation of therapy progress. More objective and reliable kinematic data can be obtained with the inertial motion capture system (IMC) by Xsens. The aim of this study was to obtain the intra- and inter-rater reliability of the TM, DI and IMC methods in five RoM tests: modified Thomas test (DI), shoulder test modified after Janda (DI), retroflexion of the trunk modified after Janda (DI), lateral inclination (TM) and fingertip-to-floor test (TM). Methods Two raters executed the RoM tests (TM or DI) in a randomized order on 22 healthy individuals while, simultaneously, the IMC data (Xsens MVN) was collected. After 15 warm-up repetitions, each rater recorded five measurements. Findings Intra-rater reliabilities were (almost) perfect for tests in all three devices (ICCs 0.886–0.996). Inter-rater reliability was substantial to (almost) perfect in the DI (ICCs 0.71–0.87) and the IMC methods (ICCs 0.61–0.993) and (almost) perfect in the TM methods (ICCs 0.923–0.961). The measurement error (ME) for the tests measured in degree (°) was 0.9–3.3° for the DI methods and 0.5–1.2° for the IMC approaches. In the tests measured in centimeters the ME was 0.5–1.3cm for the TM methods and 0.6–2.7cm for the IMC methods. Pearson correlations between the results of the DI or the TM respectively with the IMC results were significant in all tests except for the shoulder test on the right body side (r = 0.41–0.81). Interpretation Measurement repetitions of either one or multiple trained raters can be considered reliable in all three devices.

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IntroductionAgility and cognitive skills are essential in sports. However, standardized agility assessment tools often lack a reactive component, and cognitive assessments are performed using computer-based or paper-pencil tests. The SKILLCOURT is a newly developed testing and training device allowing agility and cognitive assessments in a more ecologically valid setting. This study evaluated the reliability and sensitivity to changes in performance (usefulness) of the SKILLCOURT technology.MethodsIn a test–retest (7 d, 3 months) design, 27 healthy adults (♀ = 12; age, 24.9 ± 3.3 yr) performed three trials of agility (Star Run, Random Star Run) and motor–cognitive tests (1-back, 2-back, executive function). Absolute and relative intersession and intrasession reliability was determined using the intraclass coefficient (ICC) and coefficient of variation (CV). A repeated-measures ANOVA was applied to identify potential learning effects between trials and test sessions. The smallest worthwhile change and typical error (TE) were calculated to investigate the intrasession and intersession usefulness of the tests.ResultsAgility tests revealed good relative and absolute intersession (ICC, 83–0.89; CV, 2.7%–4.1%) and intrasession (ICC, 7–0.84; CV, 2.4%–5.5%) reliability accompanied by adequate usefulness from test day 3 onward. Motor–cognitive tests showed good relative intersession reliability (ICC, 0.7–0.77) with marginal CV values (4.8%–8.6%). Adequate intrasession reliability and usefulness can be assumed from test day 2 (1-back test, executive function test) and day 3 (2-back test) onward. For all tests, learning effects were observed within and compared with test day 1.ConclusionsThe SKILLCOURT is a reliable diagnostic tool for assessing reactive agility and motor–cognitive performance. Because of learning effects, sufficient familiarization with the tests is required when used for diagnostic purposes.

Zusammenfassung Hintergrund Die staatlichen Maßnahmen zur Eindämmung des Coronavirus SARS-CoV‑2 im Jahr 2020 brachten den Trainings- und Wettkampfbetrieb im professionellen Fußball in vielen Ländern zum zeitweiligen Erliegen. In Folge des Lockdowns waren die Trainingsmöglichkeiten zumeist auf unspezifische heimbasierte Trainingsmethoden begrenzt. Es ist unklar, ob sich die fehlenden sportspezifischen Belastungsreize negativ auf die physische Leistungsfähigkeit der Fußballspielenden auswirkten. Methodik Im Rahmen eines narrativen Reviews wurde mittels einer selektiven Literaturrecherche in den Datenbanken PubMed, Google Scholar und BISp-Surf nach Studien gesucht, welche die Auswirkungen des Lockdowns auf physische Leistungsparameter bei erwachsenen professionellen Fußballspielenden untersuchten. Ergebnisse In die Übersichtsarbeit wurden sechs prospektive Längsschnittstudien eingeschlossen. In allen Studien kam während der Quarantäne ein heimbasiertes Ersatztraining zum Einsatz. Vier Studien verglichen die Leistungsfähigkeit der Fußballer/-innen mit Leistungsdaten aus vorherigen Spielzeiten. Zwei Studien ermittelten die Leistungsfähigkeit der Sportler/-innen unmittelbar vor und nach der Lockdownperiode. Diskussion Während die allgemeine Kraft- und Ausdauerleistung durch heimbasierte Ersatztrainingsprogramme erhalten werden kann, weisen die Studien darauf hin, dass sich die fehlenden spezifischen Belastungsreize vor allem negativ auf die Schnelligkeits- und Schnellkraftleistung der Fußballspielenden auswirken könnten. Bei Rückkehr in den regulären Trainingsbetrieb sollte daher auf eine progressive Belastungssteuerung insbesondere im Schnelligkeitstraining geachtet werden, um das Risiko für Verletzungen zu senken.

In football, unpredictable events (e.g. unexpected landings) seem to play a crucial role in the mechanism of non-contact knee injuries. This study investigated the effects of a single bout of an injury preventive warmup protocol on biomechanical landing stability and decision-making quality during preplanned and unanticipated jump-landings. A crossover study on 18 male amateur football players was performed. The participants completed a standard (ergometer) and an injury-preventive warmup protocol (Prevent injury and Enhance Performance (PEP)) on two different test days. After each protocol, participants performed countermovement jumps with preplanned (landing side displayed before takeoff) and unanticipated (landing side shown after takeoff) single-leg landings on a force plate. Outcomes were landing stability (height and time of the maximum vertical ground reaction force (pGRF), centre of pressure (CoP), the number of standing errors (ground contact with free leg)) and decision-making quality (landing error (wrong foot) count). Carry-over and crossover-tests were performed to find potential between-condition-differences. No carry-over effects occurred (p > .05). The PEP led to a reduced CoP trace length (−18.4 ± 32.2%, p = .021) and earlier occurrence of pGRF (−4.72 ± 6.78%, p = .017) in the preplanned condition. No significant between-treatment-differences occurred within the unanticipated landings and decision-making quality (p > .05). The primarily neuromuscular warmup protocol affects landing stability in the preplanned condition. However, it does not seem to better prepare football players for unpredictable events than a standard warmup. Trial registration: German Clinical Trials Register identifier: DRKS00016942. Highlights . Adapting movements rapidly to unanticipated external stimuli (e.g. unexpected landings) is crutial to prevent injuries in football . It is unclear wether popular neuromuscular injury preventive warmup programmes (e.g. Prevent injury and Enhance Performance (PEP)) adaquatly prepare athletes for these situations . Our study shows that the PEP warm up programme has acute effects on anticipated landing stability, but no influence on unanticipated landings or decision making quality . Classic neuromuscular warm up programmes may not be the optimal choice to prepare athletes properly for the upcoming motor-cognitive demands in a football match