Search

Background and purpose: Historically, sports training methodology, including soccer coaching, has been influenced by the pedagogic tend dominant in each epoch. Of late, the literature has espoused the idea that human learning is individual, nonlinear, and complex. Nonlinear Pedagogy (NLP) takes into account such nonlinearity and complex phenomena and facilitates each person's learning through a methodology of manipulating constraints. This learner-environment-centered approach conducts players and teams to a tactical behavior emerging through playing modified versions of games using a rich range of different constraints, for example the introduction of artificial rules. Despite the attractions of training based on constraints to research, few studies have empirically assessed the effects of these programs from a tactical perspective. The present study applies the NLP pedagogical principles of representativeness and constraints manipulation to provide youth sport academy coaches with empirical evidence of the training effects of modified games on team tactical behavior. Specifically, this study aimed to assess the short-term training effects of modified games introducing artificial rules on team tactical behavior during the team possession game phase in two youth soccer categories. Methods: Thirty-two Spanish male youth soccer players from the under-14 (U14: n = 16; age: 13.0 ± 0.4 years; playing experience: 6 ± 1 years; height: 1.56 ± 0.07 m; body mass: 46.7 ± 5.9 kg) and the under-16 (U16: n = 16; age: 15.9 ± 0.4 years; playing experience: 8 ± 1 years; height: 1.70 ± 0.07 m; body mass: 57.9 ± 8.3 kg) teams of the same club participated in the study. The natural groups were not modified for the study and the participants had some prior experience with modified games. Each team was divided into two groups who played each other during a short-term intervention distributed across four training sessions: control (CON: free play without restrictions) and experimental (EXP: modified games introducing artificial rules). Team tactical behavior was assessed, including the goalkeeper (Gk) and during the team possession game phase, using a local positioning system (LPS) before and after the intervention in an 8-a-side game with the official offside rule. Findings: Linear team tactical behavior change in centroid position, dyads, and total area values barely changed (d = trivial -- small [0.01-0.34]) after a short-term intervention of free play and modified games. Team tactical behavior tended toward greater regularity (sample entropy decrease) after artificial rules were introduced in comparison with free play without restrictions. Youth sport academy coaches who opt for organized and regular behavior during the team possession game phase could employ modified games introducing artificial rules to build up repeatable tactical patterns. Conversely, those who prefer being more chaotic and unpredictable in the game could take advantage of free play without restrictions.

Technological development has experienced exponential growth, providing more opportunity for enhancing scientific progress based on objective measures. To date, accelerometer (movement monitors) and subjective observations have led researchers to create a mark of reference in preschool education; however, the use of positioning technology is still scarce. The aim of the present article was to analyze previous research that provided behavioral information on preschoolers based on positioning systems, in order to provide a mark of reference and identify possibilities for future research. The results revealed that six studies used global positioning systems (GPS), one used a geometrical information system (GIS), and another one used video cameras for detecting location through a gridding technique. Overall, four articles used positioning systems to detect each child's indoor/outdoor location, three used these systems to identify physical activity (PA) levels, and two used systems to detect social interactions. In conclusion, the use of positioning systems in future studies is necessary to open up new lines of research to collect data in early childhood. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the reliability and the level of agreement of the ADR encoder to measure the mean propulsive velocity (MPV) of the bar in the bench press (BP) exercise on the Smith machine. Eleven males (21.6 ± 1.5 years; body mass 76.05 ± 9.73 kg) performed the protocol with isometric phase prior to concentric muscle action (PP) and the protocol in the absence of isometric phase (N-PP) for BP exercise on Smith machine. ADR encoder reported reliability values with almost perfect correlations in all training zones and protocols (PP: ICC = 0.940–0.999, r = 0.899–0.997, CV = 1.56%–4.05%, SEM = 0.0022–0.0153,and MDC = 0.006–0.031 m/s; N-PP: ICC = 0.963–0.999, r = 0.946–0.998, CV = 0.70%–3.01%, SEM = 0.0012–0.0099, and MDC = 0.003–0.027 m/s). Although the levels of agreement were high in both protocols (PP: SEM = 0.0024–0.0204 m/s, MDC = 0.007–0.057 m/s; N-PP: SEM = 0.0034–0.0288 m/s, MDC = 0.009–0.080 m/s), ADR encoder considerably underestimated the MPV values in both protocols (PP: t = −2.239 to −9.486, p < 0.001–0.01; N-PP: t = −6.901 to −17.871, p < 0.001) with respect to the gold standard (T-Force). In conclusion, ADR encoder offers high reliability for the measurement of MPV in bench press exercise performed on Smith machine regardless of their execution mode, in the entire range of intensities. However, this device is not interchangeable with T-Force since it considerably underestimates the MPV values, especially at low loads (0%–40%). Furthermore, the use of too wide load ranges suggests that the data be interpreted with caution, pending further research to corroborate the findings presented. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the internal training loads of a professional Spanish female futsal team throughout 26 weeks of training including preseason and in-season weeks and verify the impact of training period and/or training load magnitudes on heart-rate variability responses. Furthermore, we aimed to assess, intraindividually, the relationship between training load and the coefficient of variation (CV) of weekly natural log of the root mean square difference of successive normal interbeat (RR) intervals (lnRMSSDCV), obtained from ∼5 measures per week, and recorded in the seated position. Methods: A within-subject design involved 12 high-level outfield female futsal players (mean [SD] age: 23.9 [3.4] y). Results: lnRMSSD was significantly lower and lnRMSSDCV was significantly higher during the preseason (weeks 1–6) compared to in-season (weeks 7–26) (P <.001). Individually, players presented moderate to large negative correlations between lnRMSSDCV and lnRMSSD during the 26 weeks of observation. Correlations ranged between rplayer4 = −.41 (95% CI, −.69 to −.02) and rplayer12 = −.55 (−.78 to −.18). Players also presented moderate to verylarge positive correlations between lnRMSSDCV and session rating of perceived exertion. Correlations ranged between rplayer7 =.41 (.04 to.71) and rplayer1 =.71 (.45 to.86). Conclusion: Professional female futsal players in this study presented increased lnRMSSD and reduced lnRMSSDCV during 20 weeks into the competitive season compared to 6 weeks of preseason. Furthermore, lnRMSSDCV was negatively associated with lnRMSSD on an intraindividual basis. Finally, higher internal training loads were positively correlated with lnRMSSDCV, indicating that heart-rate variability is responsive to weekly training loads. [ABSTRACT FROM AUTHOR]

Specific physical qualities such as sprint running, change-of-direction or jump height are determinants of sports performance. Photocell systems are practical and easy to use systems to assess the time from point A to point B. In addition, these photoelectric systems are also used to obtain the time of vertically displaced movements. Knowing the accuracy and precision of photocell timing can be a determinant of ensuring a higher quality interpretation of results and of selecting the most appropriate devices for specific objectives. This systematic review aimed to identify and summarize studies that have examined the validity and reliability of photocells in sport sciences. A systematic review of PubMed, SPORTDiscus, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the 164 studies initially identified, 16 were fully reviewed, and their outcome measures were extracted and analyzed. Photocells appear to have a strong agreement with force plates (gold standard), but are not interchangeable to measure the vertical jump. For monitoring horizontal displacement, double beam systems, compared to single beam systems, are more valid and reliable when it comes to avoiding false triggers caused by swinging arms or legs. [ABSTRACT FROM AUTHOR]

Featured Application: Latin dance presents a safe, engaging form of weight-bearing exercise for older adults that could help to mitigate age-related physical decline. Quantifying limb impacts during dance using wearable sensors informs guidelines for an appropriate workload to strengthen lower extremity bones and muscles in older populations vulnerable to sarcopenia and falls. As global aging rises, identifying strategies to mitigate age-related physical decline has become an urgent priority. Dance represents a promising exercise modality for older adults, yet few studies have quantified the external loads older dancers experience. This study aimed to characterize the impacts accumulated across lower limb and spinal locations in older adults during Latin dance. Thirty older Latin dancers (age = 66.56 ± 6.38 years; female = 93.3%) wore inertial sensors on the scapulae, lumbar spine, knees, and ankles during a 1 h class. A distal-to-proximal gradient emerged in the total impacts (F = 429.29; p < 0.01; ωp2 = 0.43) and per intensities (F = 103.94-to-665.55; p < 0.01; ωp2 = 0.07-to-0.54), with the highest impacts sustained in the ankles (≈9000 total impacts) from 2 g to >10 g (p < 0.01; d = 1.03-to-4.95; ankles > knees > lower back > scapulae) and knees (≈12,000 total impacts) when <2 g (p < 0.01, d = 2.73-to-3.25; knees > ankles > lower back > scapulae). The majority of the impacts remained below 6 g across all anatomical locations (>94%). The impacts also increased in lower limb locations with faster tempos (r = 0.10-to-0.52; p < 0.01), while subtly accumulating over successive songs rather than indicating fatigue (r = 0.11-to-0.35; p < 0.01). The mild ankle and knee loads could strengthen the dancers' lower extremity bones and muscles in a population vulnerable to sarcopenia, osteoporosis, and falls. Quantifying the workload via accelerometry enables creating personalized dance programs to empower healthy aging. With global aging rising, this work addresses a timely public health need regarding sustainable lifelong exercise for older people. Ranging from low to moderate, the measured impact magnitudes suggest that dance lessons may provide enough osteogenic stimulus without overloading structures. [ABSTRACT FROM AUTHOR]

Validity and reliability have become crucial factors in tracking player load and positioning. One of the most important parameters to guarantee accurate measurements with radiofrequency systems is the number of reference nodes used to calculate player position. However, the accuracy of ultra-wideband (UWB) technology has only been analysed with 6 antennae. So, the purpose of the present study was to analyse the accuracy and inter-unit reliability of an UWB system with eight antennae. Three well-trained males covered 18 trajectories for the analysis of x- and y- coordinate accuracy assessment related to the positional variation among eight antennae UWB data and lines on a basketball court. This was achieved using geographical information system mapping software that calculated, for each interval and participant, the distance from the main axis of locomotion and the opposite side of the field every 0.5 s. The results showed that this is a valid system (Mean = 0.03 m; magnitude differences = 0.21% with real measures as reference; %CV <1% in all cases) for measuring locomotion and positioning. Besides, the inter-unit, test-retest and inter-subject analysis did not influence the reliability results. So, an eight antennae UWB system can be considered suitable for locomotion and positioning in an indoor environment. [ABSTRACT FROM AUTHOR]

Technological development has boosted the use of multi-sensor devices to monitor athletes' performance, but the location and connectivity between devices have been shown to affect data reliability. This preliminary study aimed to determine whether the placement of a multi-sensor device (WIMU PROTM) could affect the heart rate signal reception (GARMINTM chest strap) and, therefore, data accuracy. Thirty-two physical education students (20 men and 12 women) performed 20 min of exercise in a cycle ergometer based on the warm-up of the Function Threshold Power 20 test in laboratory conditions, carrying two WIMU PROTM devices (Back: inter-scapula; Bicycle: bicycle's handlebar—20 cm from the chest) and two GARMINTM chest straps. A one-dimensional statistical parametric mapping test found full agreement between the two situations (inter-scapula vs. bicycle's handlebar). Excellent intra-class correlation values were obtained during the warm-up (ICC = 0.99, [1.00–1.00], p < 0.001), the time trial test (ICC = 0.99, [1.00–1.00], p < 0.001) and the cool-down (ICC = 0.99, [1.00–1.00], p < 0.001). The Bland–Altman plots confirmed the total agreement with a bias value of 0.00 ± 0.1 bpm. The interscapular back placement of the WIMU PROTM device does not affect heart rate measurement accuracy with a GARMINTM chest strap during cycling exercise in laboratory conditions. [ABSTRACT FROM AUTHOR]

This study assessed the effects of playing freely and introducing artificial rules on individual tactical behaviour during the team-possession game phase in two youth soccer categories. Thirty-two developmental players from U-14 and U-16 teams participated in the study, which consisted of four identical training sessions and two test sessions performed before and after the intervention. Each team was divided into two balanced groups, free-play and conditioned, that faced each other during three eight-a-side games (Gk + 7 vs 7 + Gk) in all training sessions. The free-play groups played freely, while the conditioned ones did so constrained by artificial rules. Individual tactical behaviour was assessed during a non-constrained eight-a-side match by the distance to centroid, spatial exploration index, their entropy measures, and the regularity of each player's displacement on the length and width of the pitch using a local positioning system. In addition to the average outcomes of all the players all together, the one-by-one analysis considered the mean values of each player to appraise individual responses. While the average outcomes of all the players in both groups and categories barely changed (Cohen's d ≤ small), with a very high inter-player variability, the one-by-one analysis revealed that the training intervention affected each player's tactical behaviour differently. Introducing artificial rules decreased and raised considerably (Cohen's d ≥ moderate) in-width and exploratory regularities of most U-14 and U-16 players, respectively. Therefore, assessing the training effects of game-based interventions from the individual to the whole team may provide unique and meaningful insight regarding the tactical competence of each player. [ABSTRACT FROM AUTHOR]

Background: Velocity and acceleration have been highlighted as the most critical variables in soccer. However, there is a consensus gap in defining different levels of effort. Aim: The purpose of this systematic review is to identify if it is a consensus in those articles that proposed a threshold to establish (i) movement intensity at different velocities using tracking systems and (ii) accelerations using inertial measurement units, classifying the justification methods. Method: A systematic review of Cochrane Library, EBSCO, PubMed, Scielo, Scopus, SPORTDiscus, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: Of the 1983 studies initially identified, 39 were thoroughly reviewed, and their outcome measures were extracted and analyzed. Conclusion: The 40-m maximal linear sprint and physical fitness tests are the most commonly used methods to generate speed and acceleration thresholds in soccer. However, there is substantial heterogeneity in locomotor test procedures and workload zones established from these performance data. Studies diverged when considering the use of individualized thresholds. The low sampling rate (≤ 10 Hz) in the publications calculating acceleration and deceleration demands should also be interpreted cautiously. The present study collected evidence to help professionals process and interpret external load data. More interventional work is needed to confirm the value of fitness-based individualizations. [ABSTRACT FROM AUTHOR]