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Background: Although anterior cruciate ligament (ACL) tear-prevention programs may be effective in the (secondary) prevention of a subsequent ACL injury, little is known, yet, on their effectiveness and feasibility. This study assesses the effects and implementation capacity of a secondary preventive motor-control training (the Stop-X program) after ACL reconstruction.
Methods and design: A multicenter, single-blind, randomized controlled, prospective, superiority, two-arm design is adopted. Subsequent patients (18–35 years) with primary arthroscopic unilateral ACL reconstruction with autologous hamstring graft are enrolled. Postoperative guideline rehabilitation plus Classic follow-up treatment and guideline rehabilitation plus the Stop-X intervention will be compared. The onset of the Stop-X program as part of the postoperative follow-up treatment is individualized and function based. The participants must be released for the training components. The endpoint is the unrestricted return to sport (RTS) decision. Before (where applicable) reconstruction and after the clearance for the intervention (aimed at 4–8 months post surgery) until the unrestricted RTS decision (but at least until 12 months post surgery), all outcomes will be assessed once a month. Each participant is consequently measured at least five times to a maximum of 12 times. Twelve, 18 and 24 months after the surgery, follow-up-measurements and recurrence monitoring will follow. The primary outcome assessement (normalized knee-separation distance at the Drop Jump Screening Test (DJST)) is followed by the functional secondary outcomes assessements. The latter consist of quality assessments during simple (combined) balance side, balance front and single-leg hops for distance. All hop/jump tests are self-administered and filmed from the frontal view (3-m distance). All videos are transferred using safe big content transfer and subsequently (and blinded) expertly video-rated. Secondary outcomes are questionnaires on patient-reported knee function, kinesiophobia, RTS after ACL injury and training/therapy volume (frequency – intensity – type and time). All questionnaires are completed online using the participants’ pseudonym only.
Group allocation is executed randomly. The training intervention (Stop-X arm) consists of self-administered home-based exercises. The exercises are step-wise graduated and follow wound healing and functional restoration criteria. The training frequency for both arms is scheduled to be three times per week, each time for a 30 min duration. The program follows current (secondary) prevention guidelines.
Repeated measurements gain-score analyses using analyses of (co-)variance are performed for all outcomes.
Trial registration: German Clinical Trials Register, identification number DRKS00015313. Registered on 1 October 2018.
Beneficial acute effects of resistance exercise on cognitive functions may be modified by exercise intensity or by habitual physical activity. Twenty-six participants (9 female and 17 male; 25.5 ± 3.4 years) completed four resistance exercise interventions in a randomized order on separate days (≥48 h washout). The intensities were set at 60%, 75%, and 90% of the one repetition maximum (1RM). Three interventions had matched workloads (equal resistance*nrepetitions). One intervention applied 75% of the 1RM and a 50% reduced workload (resistance*nrepetitions = 50%). Cognitive attention (Trail Making Test A—TMTA), task switching (Trail Making Test B—TMTB), and working memory (Digit Reading Spans Backward) were assessed before and immediately after exercise. Habitual activity was assessed as MET hours per week using the International Physical Activity Questionnaire. TMTB time to completion was significantly shorter after exercise with an intensity of 60% 1RM and 75% 1RM and 100% workload. Friedman test indicated a significant effect of exercise intensity in favor of 60% 1RM. TMTA performance was significantly shorter after exercise with an intensity of 60% 1RM, 90% 1RM, and 75% 1RM (50% workload). Habitual activity with vigorous intensity correlated positively with the baseline TMTB and Digit Span Forward performance but not with pre- to post-intervention changes. Task switching, based on working memory, mental flexibility, and inhibition, was beneficially influenced by acute exercise with moderate intensity whereas attention performance was increased after exercise with moderate and vigorous intensity. The effect of regular activity had no impact on acute exercise effects.
Background: The effects of blood flow restriction (training) may serve as a model of peripheral artery disease. In both conditions, circulating micro RNAs (miRNAs) are suggested to play a crucial role during exercise-induced arteriogenesis. We aimed to determine whether the profile of circulating miRNAs is altered after acute resistance training during blood flow restriction (BFR) as compared with unrestricted low- and high-volume training, and we hypothesized that miRNA that are relevant for arteriogenesis are affected after resistance training.
Methods: Eighteen healthy volunteers (aged 25 ± 2 years) were enrolled in this three-arm, randomized-balanced crossover study. The arms were single bouts of leg flexion/extension resistance training at (1) 70% of the individual single-repetition maximum (1RM), (2) at 30% of the 1RM, and (3) at 30% of the 1RM with BFR (artificially applied by a cuff at 300 mm Hg). Before the first exercise intervention, the individual 1RM (N) and the blood flow velocity (m/s) used to validate the BFR application were determined. During each training intervention, load-associated outcomes (fatigue, heart rate, and exhaustion) were monitored. Acute effects (circulating miRNAs, lactate) were determined using pre-and post-intervention measurements.
Results: All training interventions increased lactate concentration and heart rate (p < 0.001). The high-intensity intervention (HI) resulted in a higher lactate concentration than both lower-intensity training protocols with BFR (LI-BFR) and without (LI) (LI, p = 0.003; 30% LI-BFR, p = 0.008). The level of miR-143-3p was down-regulated by LI-BFR, and miR-139-5p, miR-143-3p, miR-195-5p, miR-197-3p, miR-30a-5p, and miR-10b-5p were up-regulated after HI. The lactate concentration and miR-143-3p expression showed a significant positive linear correlation (p = 0.009, r = 0.52). A partial correlation (intervention partialized) showed a systematic impact of the type of training (LI-BFR vs. HI) on the association (r = 0.35 remaining after partialization of training type).
Conclusions: The strong effects of LI-BFR and HI on lactate- and arteriogenesis-associated miRNA-143-3p in young and healthy athletes are consistent with an important role of this particular miRNA in metabolic processes during (here) artificial blood flow restriction. BFR may be able to mimic the occlusion of a larger artery which leads to increased collateral flow, and it may therefore serve as an external stimulus of arteriogenesis.
Adapting movements rapidly to unanticipated external stimuli is paramount for athletic performance and to prevent injuries. We investigated the effects of a 4-week open-skill choice-reaction training intervention on unanticipated jump-landings. Physically active adults (n = 37; mean age 27, standard deviation 2.7 years, 16 females, 21 males) were randomly allocated to one of two interventions or a control group (CG). Participants in the two intervention groups performed a 4-week visuomotor open skill choice reaction training, one for the upper and one for the lower extremities. Before and after the intervention, two different types of countermovement jumps with landings in split stance position were performed. In the (1) pre-planned condition, we informed the participants regarding the landing position (left or right foot in front position) before the jump. In the (2) unanticipated condition, this information was displayed after take-off (350–600 ms reaction time before landing). Outcomes were landing stability [peak vertical ground reaction force (pGRF) and time to stabilization (TTS)], and landing-related decision-making quality (measured by the number of landing errors). To measure extremity-specific effects, we documented the number of correct hits during the trained drills. A two-factorial (four repeated measures: two conditions, two time factors; three groups) ANCOVA was carried out; conditions = unanticipated versus pre-planned condition, time factors = pre versus post measurement, grouping variable = intervention allocation, co-variates = jumping time and self-report arousal. The training improved performance over the intervention period (upper extremity group: mean of correct choice reaction hits during 5 s drill: +3.0 hits, 95% confidence interval: 2.2–3.9 hits; lower extremity group: +1.6 hits, 0.6–2.6 hits). For pGRF (F = 8.4, p < 0.001) and landing errors (F = 17.1, p < 0.001) repeated measures effect occurred. Significantly more landing errors occurred within the unanticipated condition for all groups and measurement days. The effect in pGRF is mostly impacted by between-condition differences in the CG. No between-group or interaction effect was seen for these outcomes: pGRF (F = 0.4, p = 0.9; F = 2.3, p = 0.1) landing errors (F = 0.5, p = 0.6; F = 2.3, p = 0.1). TTS displayed a repeated measures (F = 4.9, p < 0.001, worse values under the unanticipated condition, improvement over time) and an interaction effect (F = 2.4, p = 0.03). Healthy adults can improve their choice reaction task performance by training. As almost no transfer to unanticipated landing successfulness or movement quality occurred, the effect seems to be task-specific. Lower-extremity reactions to unanticipated stimuli may be improved by more specific training regimens.
Low-to-moderate quality meta-analytic evidence shows that motor control stabilisation exercise (MCE) is an effective treatment of non-specific low back pain. A possible approach to overcome the weaknesses of traditional meta-analyses would be that of a prospective meta-analyses. The aim of the present analysis was to generate high-quality evidence to support the view that motor control stabilisation exercises (MCE) lead to a reduction in pain intensity and disability in non-specific low back pain patients when compared to a control group. In this prospective meta-analysis and sensitivity multilevel meta-regression within the MiSpEx-Network, 18 randomized controlled study arms were included. Participants with non-specific low back pain were allocated to an intervention (individualized MCE, 12 weeks) or a control group (no additive exercise intervention). From each study site/arm, outcomes at baseline, 3 weeks, 12 weeks, and 6 months were pooled. The outcomes were current pain (NRS or VAS, 11 points scale), characteristic pain intensity, and subjective disability. A random effects meta-analysis model for continuous outcomes to display standardized mean differences between intervention and control was performed, followed by sensitivity multilevel meta-regressions. Overall, 2391 patients were randomized; 1976 (3 weeks, short-term), 1740 (12 weeks, intermediate), and 1560 (6 months, sustainability) participants were included in the meta-analyses. In the short-term, intermediate and sustainability, moderate-to-high quality evidence indicated that MCE has a larger effect on current pain (SMD = −0.15, −0.15, −0.19), pain intensity (SMD = −0.19, −0.26, −0.26) and disability (SMD = −0.15, −0.27, −0.25) compared with no exercise intervention. Low-quality evidence suggested that those patients with comparably intermediate current pain and older patients may profit the most from MCE. Motor control stabilisation exercise is an effective treatment for non-specific low back pain. Sub-clinical intermediate pain and middle-aged patients may profit the most from this intervention.
Patienten mit chronisch-unspezifischen Nackenschmerzen weisen Studien zufolge ein gegenüber symptomfreien Personen pathologisch verändertes Bewegungsverhalten der Halswirbelsäule auf. Aktuelle Untersuchungen bestätigen dabei eine im Vergleich zu gesunden, symptomfreien Probanden verminderte Beweglichkeit der Zervikalregion. Mit dem Fokus auf sensomotorische Funktionen deuten Studien zudem ein erhöhtes Maß an nicht-intendierter Bewegungsvariabilität sowie ein vermindertes Maß an Nebenbewegungen in andere Ebenen bei der Durchführung zweidimensionaler Bewegungsabfolgen an. Demgegenüber verändert sich bei symptomfreien Personen das zervikale Bewegungs-verhalten im Altersverlauf. Aktuelle Untersuchungen indizieren dabei eine im Alter erhöhte Bewegungsvariabilität. Zusätzlich indizieren Studien ein mit zunehmendem Alter geringer werdendes maximales Bewegungsausmaß der Halswirbelsäule. Publizierte Normwerte drücken diese altersabhängigen Veränderungen jedoch nur grob kategorisierend für größere Altersspannen aus. Daten zu möglichen Zuordnungsmöglichkeiten von Patienten und gesunden Personen anhand trennscharfer Schwellenwerten zum Bewegungsausmaß und zur Bewegungskonsistenz fehlen gänzlich.Vor diesem Hintergrund war das Ziel der Studie die Entwicklung und Validierung klassifikatorischer Modelle zur Diskriminierung von symptomatischem und asympto-matischem zervikalem Bewegungsverhalten. Symptomfreie Probanden (120) wurden konsekutiv der Modellentwicklung (n = 100, 18 – 75 Jahre, 36 f) bzw. der Modellvalidierung zugeteilt (n = 20, 23 – 75 Jahre, 15 f). Zusätzlich wurden zur Modellvalidierung ebenfalls 20 Patienten mit chronisch-unspezifischen Nackenschmerzen eingeschlossen (22 – 71 Jahre, 15 f). Alle Probanden absolvierten initial eine Bewegungsanalyse zur Erhebung des Bewegungsverhaltens der Halswirbelsäule. Diese beinhaltet ein Set zu fünf repetitiven zervikalen Flexions-/Extensions-Bewegungszyklen. Die kinematischen Variablen wurden dabei ultraschalltopometrisch erfasst. Diese standardisierte Erhebung erfolgte in stabiler aufrechter Positionierung und selbstgewählter Geschwindigkeit unter Verwendung eines nichtinvasiven 3D-Bewegungsanalysesystems. Die kinematischen Charakteristika, bestehend aus maximalem Bewegungsausmaß in der Sagittalebene (ROM), den Variationskoeffizienten (CV) sowie den mittleren Nebenbewegungen in Frontal- und Transversalebene (NEB) wurden final aus den Rohdaten berechnet. Im Anschluss erfolgte die Modellentwicklung auf Basis von Cut-Offs. Dies geschah mittels der Erstellung von voraussetzungskonformen linearen Regressionsmodellen. Unabhängige Variable war dabei das Alter, die abhängige Variable stellte das jeweilige kinematische Charakteristikum dar. Die Cut-Offs beschrieben jeweils die Prognose-Konfidenzintervalle der Regressionsgeraden (90% Prognose-Konfidenzintervall für individuelle Werte (ind) und 95% Prognose-Konfidenzintervall für Mittelwerte (MW)). Die Werte der kinematischen Analyse jedes Probanden, der in die Modellvalidierung der entwickelten Cut-Offs eingeschlossen wurde, wurden anschließend mittels dieser Cut-Offs klassifiziert als ‘asymptomatisch’ oder ‘symptomatisch’. Auf der Basis dieser Zuteilung wurden die Cut-Offs stringent mittels Vierfeldertafeln auf ihre Trennschärfe in der Diskriminierung von chronisch-unspezifischen Nackenschmerzpatienten und symptomfreien Personen überprüft. Alle entwickelten Modelle wiesen einen gerichteten linearen Zusammenhang zwischen Alter und dem jeweiligen kinematischen Charakteristikum auf. Auf Basis der internen Validierung beinhaltet das 95%-Konfidenzintervall der Steigung der Regressionsgeraden in dem vorliegenden Modell den Nullwert nicht und schließt zudem bei allen drei Modellen die bei der Erstellung des Modells gefundene Steigung ein. Bei der Modellvalidierung ergab die Bewertung der Vierfeldertafeln überzufällige Unterschiede zwischen erwarteter und beobachteter Häufigkeitsverteilung der mittels Prognose-Konfidenzintervalle für Mittelwerte für ROM (ROMMW; Chi2= 6.8; p< .01) und CV (CVMW; Chi2= 6.42; p< .05) klassierten kinematischen Größen, nicht jedoch für die vier anderen Klassifikatoren (p> .05). Im Anschluss ergab die Analyse der Trennschärfe der Modelle mit überzufälliger Merkmalsverteilung eine Sensitivität von 60 % für ROMMW und von 75 % für CVMW. Die Spezifität betrug 85 % für ROMMW und 65 % für CVMW. Die Resultate demonstrieren einerseits einen linearen Zusammenhang von Alter und verschiedener kinematischer Charakteristika sowie eine überzufällige Merkmalsverteilung für die Modelle ROMMW und CVMW mit ausreichender Spezifität und Sensitivität und – daraus hervorgehend – eine ausreichende Trennschärfe der klassifikatoren in der Differenzierung von symptomatischen und asymptomatischen Bewegungsmustern. Die Resultate sind einerseits im Einklang mit anderen – kategorisierenden – Studienresultaten und ergänzen andererseits – durch die Erstellung und Bewertung trennscharfer Klassifikatoren – den aktuellen Forschungsstand konsekutiv. Die Trennschärfe-Indizes bewegen sich dabei in vergleichbarer Größenordnung wie andere (subjektive) Klassifikatoren (z.B. Schmerzstärke) zur Einordnung von Nackenschmerzpatienten. Insbesondere in der individuellen Beurteilung, aber auch für mögliche prospektive Vergleiche sind valide Ein ordnungskriterien von Belangen und bieten gegenüber einfachen kategorisierenden Gruppenwerten genauere und verlässlichere Klassierungen. Zukünftige Forschungsaktivitäten sollten sich insbesondere mit der Übertragbarkeit vorliegender Cut-Offs auf interventionsinduzierte individuelle Veränderungen auseinandersetzen.
Background: Arising from the relevance of sensorimotor training in the therapy of nonspecific low back pain patients and from the value of individualized therapy, the present trial aims to test the feasibility and efficacy of individualized sensorimotor training interventions in patients suffering from nonspecific low back pain.
Methods and study design: A multicentre, single-blind two-armed randomized controlled trial to evaluate the effects of a 12-week (3 weeks supervised centre-based and 9 weeks home-based) individualized sensorimotor exercise program is performed. The control group stays inactive during this period. Outcomes are pain, and pain-associated function as well as motor function in adults with nonspecific low back pain. Each participant is scheduled to five measurement dates: baseline (M1), following centre-based training (M2), following home-based training (M3) and at two follow-up time points 6 months (M4) and 12 months (M5) after M1. All investigations and the assessment of the primary and secondary outcomes are performed in a standardized order: questionnaires – clinical examination – biomechanics (motor function). Subsequent statistical procedures are executed after the examination of underlying assumptions for parametric or rather non-parametric testing.
Discussion: The results and practical relevance of the study will be of clinical and practical relevance not only for researchers and policy makers but also for the general population suffering from nonspecific low back pain.
Background: Self-myofascial release (SMR) aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are still poorly understood. In addition to neuronal mechanisms, improved flexibility may be driven by acute morphological adaptations, such as a reduction in passive tissue stiffness or improved movement between fascial layers. The aim of the intended study is to evaluate the acute effects of SMR on the passive tissue stiffness of the anterior thigh muscles and the sliding properties of the associated fasciae.
Methods: In a crossover study de sign, 16 participants will receive all of the following interventions in a permutated random order: (1) one session of 2 × 60 s of SMR at the anterior thigh, (2) one session of 2 × 60 s of passive static stretching of the anterior thigh and (3) no intervention. Passive tissue stiffness, connective tissue sliding, angle of first stretch sensation, as well as maximal active and passive knee flexion angle, will be evaluated before and directly after each intervention.
Discussion: The results of the intended study will allow a better understanding of, and provide further evidence on, the local effects of SMR techniques and the underlying mechanisms for flexibility improvements.
A large body of evidence suggests that the 11+ warm-up programme is effective in preventing football-related musculoskeletal injuries. However, despite considerable efforts to promote and disseminate the programme, it is unclear as to whether team head coaches are familiar with the 11+ and how they rate its feasibility. The present study aimed to gather information on awareness and usage among German amateur level football coaches. A questionnaire was administered to 7893 individuals who were in charge of youth and adult non-professional teams. Descriptive and inferential statistics were used to analyse the obtained data. A total of 1223 coaches (16%) returned the questionnaire. There was no risk of a non-response bias (p>.05). At the time of the survey, nearly half of the participants (42.6%) knew the 11+. Among the coaches who were familiar with the programme, three of four reported applying it regularly (at least once per week). Holding a license (φ = .28, p < .0001), high competitive level (Cramer-V = .13, p = .007), and coaching a youth team (φ = .1, p = .001) were associated with usage of 11+. Feasibility and suitability of the 11+ were rated similarly by aware and unaware coaches. Although a substantial share of German amateur level coaches is familiar with the 11+, more than half of the surveyed participants did not know the programme. As the non-usage does not appear to stem from a lack of rated feasibility and suitability, existing communication strategies might need to be revised.
