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Agility, as the ability to react rapidly to unforeseen events, is an essential component of football performance. However, existing agility diagnostics often do not reflect the complex motor–cognitive interaction required on the field. Therefore, this study evaluates the criterion and ecological validity of a newly developed motor–cognitive dual-task agility approach in elite youth football players and compare it to a traditional reactive agility test. Twenty-one male youth elite football players (age:17.4 ±0 .6; BMI:23.2 ± 1.8) performed two agility tests (reactive agility, reactive agility with integrated multiple-object-tracking (Dual-Task Agility)) on the SKILLCOURT system. Performance was correlated to motor (sprint, jump), cognitive (executive functions, attention, reaction speed) and football specific tests (Loughborough soccer passing test (LSPT)) as well as indirect game metrics (coaches' rating, playing time). Reactive agility performance showed moderate correlations to attention and choice reaction times (r = 0.48−0.63), as well as to the LSPT (r = 0.51). The dual-task agility test revealed moderate relationships with attention and reaction speed (r = 0.47−0.58), executive functions (r = 0.45−0.63), as well as the game metrics (r = 0.51−0.61). Finally, the dual-task agility test significantly differentiated players based on their coaches' rating and playing time using a median split (p < 0.05; d = 0.8–1.28). Motor–cognitive agility performance in elite youth football players seems to be primarily determined by cognitive functions. The integration of multiple object tracking into reactive agility testing seems to be an ecologically valid approach for performance diagnostics in youth football.
Highlights
* The study introduces a novel motor–cognitive dual-task agility approach (incorporation of multiple-object-tracking in agility testing), evaluating its criterion and ecological validity in elite youth football players compared to a standard agility test.
* The standard agility test was shown to have moderate correlations with attention and choice reaction times, while the dual-task agility approach additionally incorporates executive functions
* While the agility test correlates to football-specific test performance, the dual-task agility test significantly discriminates players based on their potential ratings and in-season playing time, highlighting its potential as a valuable tool for assessing performance in youth football.
* The findings suggest that agility performance in elite youth football is primarily determined by cognitive functions
* Incorporating more complex cognitive elements such as multiple-object-tracking in agility testing may improve ecological validity and therefore the predictive value of the testing procedure.
Objectiv:e To explore the association of physical activity (PA) with musculoskeletal pain (MSK pain).
Design: Cross-sectional study
Setting: 14 countries (Argentina, Australia, Austria, Brazil, Chile, France, Germany, Italy, the Netherlands, Singapore, South Africa, Spain, Switzerland and the USA).
Participants: Individuals aged 18 or older.
Primary and secondary outcome measures: PA volumes were assessed with an adapted version of the Nordic Physical Activity Questionnaire-short. Prevalence of MSK pain was captured by means of a 20-item checklist of body locations. Based on the WHO recommendation on PA, participants were classified as non-compliers (0–150 min/week), compliers (150–300 min/week), double compliers (300–450 min/week), triple compliers (450–600 min/week), quadruple compliers (600–750 min/week), quintuple compliers (750–900 min/week) and top compliers (more than 900 min/week). Multivariate logistic regression was used to obtain adjusted ORs of the association between PA and MSK pain for each body location, correcting for age, sex, employment status and depression risk.
Results: A total of 13 741 participants completed the survey. Compared with non-compliers, compliers had smaller odds of MSK pain in one location (thoracic pain, OR 0.77, 95% CI 0.64 to 0.93). Double compliance was associated with reduced pain occurrence in six locations (elbow, OR 0.70, 95% CI 0.50 to 0.98; forearm, OR 0.63, 95% CI 0.40 to 0.99; wrist, OR 0.74, 95% CI 0.57 to 0.98; hand, OR 0.57, 95% CI 0.40 to 0.79; fingers, OR 0.72, 95% CI 0.52 to 0.99; abdomen, OR 0.61, 95% CI 0.41 to 0.91). Triple to top compliance was also linked with lower odds of MSK pain (five locations in triple compliance, three in quadruple compliance, two in quintuple compliance, three in top compliance), but, at the same time, presented increased odds of MSK pain in some of the other locations.
Conclusion: A dose of 300–450 min WHO-equivalent PA/week was associated with lower odds of MSK pain in six body locations. On the other hand, excessive doses of PA were associated with higher odds of pain in certain body locations.
Background/Objectives: Agility and cognitive abilities are typically assessed separately by different motor and cognitive tests. While many agility tests lack a reactive decision-making component, cognitive assessments are still mainly based on computer-based or paper-pencil tests with low ecological validity. This study is the first to validate the novel SKILLCOURT technology as an integrated assessment tool for agility and cognitive-motor performance.
Methods: Thirty-two healthy adults performed agility (Star Run), reactive agility (Random Star Run) and cognitive-motor (executive function test, 1-back decision making) performance assessments on the SKILLCOURT. Cognitive-motor tests included lower limb responses in a standing position to increase the ecological validity when compared to computer-based tests. Test results were compared to established motor and agility tests (countermovement jump, 10 m linear sprint, T-agility tests) as well as computer-based cognitive assessments (choice-reaction, Go-NoGo, task switching, memory span). Correlation and multiple regression analyses quantified the relation between SKILLCOURT performance and motor and cognitive outcomes.
Results: Star Run and Random Star Run tests were best predicted by linear sprint (r = 0.68, p < 0.001) and T-agility performance (r = 0.77, p < 0.001), respectively. The executive function test performance was well explained by computer-based assessments on choice reaction speed and cognitive flexibility (r = 0.64, p < 0.001). The 1-back test on the SKILLCOURT revealed moderate but significant correlations with the computer-based assessments (r = 0.47, p = 0.007).
Conclusion: The results support the validity of the SKILLCOURT technology for agility and cognitive assessments in more ecologically valid cognitive-motor tasks. This technology provides a promising alternative to existing performance assessment tools.
A recent in-vivo experiment has shown that force can be transmitted between the gastrocnemius and the hamstring muscles due to a direct tissue continuity. However, it remains unclear if this mechanical interaction is affected by the stiffness of the structural connection. This study therefore aimed to investigate the impact of the knee angle on myofascial force transmission across the dorsal knee. A randomized, cross-over study was performed, including n = 56 healthy participants (25.36 ± 3.9 years, 25 females). On two separate days, they adopted a prone position on an isokinetic dynamometer (knee extended or 60° flexed). In each condition, the device moved the ankle three times from maximal plantarflexion to maximal dorsal extension. Muscle inactivity was ensured using EMG. High-resolution ultrasound videos of the semimembranosus (SM) and the gastrocnemius medialis (GM) soft tissue were recorded. Maximal horizontal tissue displacement, obtained using cross-correlation, was examined as a surrogate of force transmission. SM tissue displacement was higher at extended (4.83 ± 2.04 mm) than at flexed knees (3.81 ± 2.36 mm). Linear regression demonstrated significant associations between (1) SM and GM soft tissue displacement (extended: R2 = 0.18, p = 0.001; flexed: R2 = 0.17, p = 0.002) as well as (2) SM soft tissue displacement and ankle range of motion (extended: R2 = 0.103, p = 0.017; flexed: R2 = 0.095, p = 0.022). Our results further strengthen the evidence that local stretching induces a force transmission to neighboring muscles. Resulting remote exercise effects such as increased range of motion, seem to depend on the stiffness of the continuity.
Trial registration: DRKS (Deutsches Register Klinischer Studien), registration number DRKS00024420, first registered 08/02/2021, https://drks.de/search/de/trial/DRKS00024420.
Background: Knee osteoarthritis is associated with higher kinetic friction in the knee joint, hence increased acoustic emissions during motion. Decreases in compressive load and improvements in movement quality might reduce this friction and, thus, sound amplitude. We investigated if an exercise treatment acutely affects knee joint sounds during different activities of daily life.
Methods: Eighteen participants with knee osteoarthritis (aged 51.8 ± 7.3 years; 14 females) were included in this randomized crossover trial. A neuromuscular exercise intervention and a placebo laser needle acupuncture treatment were performed. Before and after both interventions, knee joint sounds were measured during three different activities of daily living (standing up/sitting down, walking, descending stairs) by means of vibroarthrography. The mean amplitude (dB) and the median power frequency (MPF, Hz) were assessed at the medial tibial plateau and the patella. Differences in knee acoustic emissions between placebo and exercise interventions were calculated by analyses of covariance.
Results: Controlled for participant's age, knee demanding activity level and osteoarthritis stage, the conditions significantly differed in their impact on the MPF (mean(± SD) pre-post-differences standing up: placebo: 9.55(± 29.15) Hz/ exercise: 13.01(± 56.06) Hz, F = 4.9, p < 0.05) and the amplitude (standing up: placebo:0.75(± 1.43) dB/ exercise: 0.51(± 4.68) dB, F = 5.0, p < 0.05; sitting down: placebo: 0.07(± 1.21) dB/ exercise: -0.16(± .36) dB, F = 4.7, p < 0.05) at the tibia. There were no differences in the MPF and amplitude during walking and descending stairs (p > 0.05). At the patella, we found significant differences in the MPF during walking (placebo 0.08(± 1.42) Hz/ exercise: 15.76(± 64.25) Hz, F = 4.8, p < .05) and in the amplitude during descending stairs (placebo: 0.02 (± 2.72) dB/ exercise: -0.73(± 2.84) dB, F = 4.9, p < 0.05). There were no differences in standing up/ sitting down for both parameters, nor in descending stairs for the MPF and walking for the amplitude (p > 0.05).
Conclusion: The MPF pre-post differences of the exercise intervention were higher compared to the MPF pre-post differences of the placebo treatment. The amplitude pre-post differences were lower in the exercise intervention. In particular, the sound amplitude might be an indicator for therapy effects in persons with knee osteoarthritis.
Trial registration: The study was retrospectively registered in the German Clinical Trials Register (DRKS00022936, date of registry: 26/08/2020).
Fitness and exercise may counteract the detrimental metabolic and mood adaptations during prolonged sitting. This study distinguishes the immediate effects of a single bout vs. work-load and intensity-matched repeated exercise breaks on subjective well-being, blood glucose, and insulin response (analyzed as area under the curve) during sedentary time; and assesses the influence of fitness and caloric intake on metabolic alterations during sedentariness. Eighteen women underwent cardiopulmonary exercise testing and three 4 h sitting interventions: two exercise interventions (70% VO2max, 30 min, cycle ergometer: (1) cycling prior to sitting; (2) sitting interrupted by 5 × 6 min cycling), and one control condition (sitting). Participants consumed one meal with ad libitum quantity (caloric intake), but standardized macronutrient proportion. Exercise breaks (4057 ± 2079 μU/mL·min) reduced insulin values compared to a single bout of exercise (5346 ± 5000 μU/mL·min) and the control condition (6037 ± 3571 μU/mL·min) (p ≤ 0.05). ANCOVA revealed moderating effects of caloric intake (519 ± 211 kilocalories) (p ≤ 0.01), but no effects of cardiorespiratory fitness (41.3 ± 4.2 mL/kg/min). Breaks also led to lower depression, but higher arousal compared to a no exercise control (p ≤ 0.05). Both exercise trials led to decreased agitation (p ≤ 0.05). Exercise prior to sitting led to greater peace of mind during sedentary behavior (p ≤ 0.05). Just being fit or exercising prior to sedentary behavior are not feasible to cope with acute detrimental metabolic changes during sedentary behavior. Exercise breaks reduce the insulin response to a meal. Despite their vigorous intensity, breaks are perceived as positive stimulus. Detrimental metabolic changes during sedentary time could also be minimized by limiting caloric intake.
Delayed-onset muscle soreness (DOMS) is a common symptom in people participating in exercise, sport, or recreational physical activities. Several remedies have been proposed to prevent and alleviate DOMS. In 2008 and 2015, two studies have been conducted to investigate the effects of acupuncture on symptoms and muscle function in eccentric exercise-induced DOMS of the biceps brachii muscle. In 2008 a prospective, randomized, controlled, observer and subject-blinded trial was undertaken with 22 healthy subjects (22–30 years; 12 females) being randomly assigned to three treatment groups: real acupuncture (deep needling at classic acupuncture points and tender points; n = 7), sham-acupuncture (superficial needling at non-acupuncture points; n = 8), and control (n = 7). In 2015, a five-arm randomized controlled study was conducted with 60 subjects (22 females, 23.6 ± 2.8 years). Participants were randomly allocated to needle, laser, sham needle, sham laser acupuncture, and no intervention.
In both cases treatment was applied immediately, 24 and 48 hours after DOMS induction.
The outcome measures included pain perception (visual analogue scale; VAS), mechanical pain threshold (MPT), maximum isometric voluntary force (MIVF) and pressure pain threshold (PPT).
Results: In 2008, following nonparametric testing, there were no significant differences between groups in outcome measures at baseline. After 72 hours, pain perception (VAS) was significantly lower in the acupuncture group compared to the sham acupuncture and control subjects. However, the mean MPT and MIVF scores were not significantly different between groups. This lead to the conclusion, that acupuncture seemed to have no effects on MPT and muscle function, but reduced perceived pain arising from exercise-induced DOMS.
The more recent results from 2015 indicated that neither verum nor sham interventions significantly improved outcomes within 72 hours when compared with the no treatment control (P > 0.05).
A glenohumeral internal rotation deficit (GIRD) of the shoulder, is associated with an increased risk of shoulder injuries in tennis athletes. The aim of the present study was to reveal the impact of 1) age, sex, specific training data (i.e. training volume, years of tennis practice, years of competitive play) and 2) upper extremity injuries on GIRD in youth competitive tennis athletes.
A cross-sectional retrospective study design was adopted. Youth tennis players (n = 27, 12.6 ± 1.80 yrs., 18 male) belonging to an elite tennis squad were included. After documenting the independent variables (anthropometric data, tennis specific data and history of injury), the players were tested for internal (IR) and external (ER) shoulder rotation range of motion (RoM, [°]). From these raw values, the GIRD parameters ER/IR ratio and side differences and TRoM side differences were calculated. Pearson’s correlation analyses were performed to find potential associations of the independent variables with the GIRD outcomes.
A significant positive linear correlation between the years of tennis training and IR side asymmetry occurred (p < .05). A significant negative linear relation between the years of tennis training and the ratio of ER to IR range of motion (RoM) in the dominant side (p < .05) was found. The analysis of covariance showed a significant influence of the history of injuries on IR RoM (p < .05).
Injury and training history but not age or training volume may impact on glenohumeral internal rotation deficit in youth tennis athletes. We showed that GIRD in the dominant side in youth tennis players is progressive with increasing years of tennis practice and independent of years of practice associated with the history of injuries. Early detection of decreased glenohumeral RoM (specifically IR), as well as injury prevention training programs, may be useful to reduce GIRD and its negative consequences.
Background: Excessive unilateral joint loads may lead to overuse disorders. Bilateral training in archery is only performed as a supportive coordination training and as a variation of typical exercise. However, a series of studies demonstrated a crossover transfer of training-induced motor skills to the contralateral side, especially in case of mainly unilateral skills. We compared the cervical spine and shoulder kinematics of unilateral and bilateral training archers.
Methods: In this cross-sectional study, 25 (5 females, 48 ± 14 years) bilaterally training and 50 age-, sex- and level-matched (1:2; 47.3 ± 13.9 years) unilaterally training competitive archers were included. Cervical range of motion (RoM, all planes) and glenohumeral rotation were assessed with an ultrasound-based 3D motion analysis system. Upward rotation of the scapula during abduction and elevation of the arm were measured by means of a digital inclinometer and active shoulder mobility by means of an electronic caliper. All outcomes were compared between groups (unilaterally vs. bilaterally) and sides (pull-hand- vs. bow-hand-side).
Results: Unilateral and bilateral archers showed no between group and no side-to-side-differences in either of the movement direction of the cervical spine. The unilateral archers had higher pull-arm-side total glenohumeral rotation than the bilateral archers (mean, 95% CI), (148°, 144–152° vs. 140°, 135°-145°). In particular, internal rotation (61°, 58–65° vs. 56°, 51–61°) and more upward rotation of the scapula at 45 degrees (12°, 11–14° vs. 8°, 6–10°), 90 degrees (34°, 31–36° vs. 28°, 24–32°), 135 degrees (56°, 53–59° vs. 49°, 46–53°), and maximal (68°, 65–70° vs. 62°, 59–65°) arm abduction differed. The bow- and pull-arm of the unilateral, but not of the bilateral archers, differed in the active mobility of the shoulder (22 cm, 20–24 cm vs. 18 cm, 16–20 cm).
Conclusions: Unilaterally training archers display no unphysiologic movement behaviour of the cervical spine, but show distinct shoulder asymmetris in the bow- and pull-arm-side when compared to bilateral archers in glenohumeral rotation, scapula rotation during arm abduction, and active mobility of the shoulder. These asymmetries in may exceed physiological performance-enhancing degrees. Bilateral training may seems appropriate in archery to prevent asymmetries.
Background and aims: One reason for the controversial discussion of whether the dual task (DT) walking paradigm has an added value for diagnosis in clinical conditions might be the use of different gait measurement systems. Therefore, the purpose was 1) to detect DT effects of central gait parameters obtained from five different gait analysis devices in young and old adults, 2) to assess the consistency of the measurement systems, and 3) to determine if the absolut and proportional DT costs (DTC) are greater than the system-measurement error under ST. Methods: Twelve old (72.2 ± 7.9y) and 14 young adults (28.3 ± 6.2y) walked a 14.7-m distance under ST and DT at a self-selected gait velocity. Interrater reliability, precision of the measurement and sensitivity to change were calculated under ST and DT. Results: An age effect was observed in almost all gait parameters for the ST condition. For DT only differences for stride length (p < .029, ɳ2p = .239) as well as single and double limb support (p = .036, ɳ2p = .227; p = .034, ɳ2p = .218) remained. The measurement systems showed a lower absolute agreement compared to consistency across all systems. Conclusions: When reporting DT effects, the real changes in performance and random measurement errors should always be accounted for. These findings have strong implications for interpreting DT effects.