Long-term motor skill training with individually adjusted progressive difficulty enhances learning and promotes corticospinal plasticity

Motor skill acquisition depends on central nervous plasticity. However, behavioural determinants leading to long lasting corticospinal plasticity and motor expertise remain unexplored. Here we investigate behavioural and electrophysiological effects of individually tailored progressive practice during long-term motor skill training. Two groups of participants practiced a visuomotor task requiring precise control of the right digiti minimi for 6 weeks. One group trained with constant task difficulty, while the other group trained with progressively increasing task difficulty, i.e. continuously adjusted to their individual skill level. Compared to constant practice, progressive practice resulted in a two-fold greater performance at an advanced task level and associated increases in corticospinal excitability. Differences were maintained 8 days later, whereas both groups demonstrated equal retention 14 months later. We demonstrate that progressive practice enhances motor skill learning and promotes corticospinal plasticity. These findings underline the importance of continuously challenging patients and athletes to promote neural plasticity, skilled performance, and recovery

Physical performance and loading for six playing positions in elite female football: full‐game, end‐game, and peak periods

The present study investigated the position-specific match demands and heart rate response of female elite footballers, with special focus on the full-game, end-game, and peak-intensity periods. In total, 217 match observations were performed in 94 players from all eight teams of the best Danish Women's League, that is, goalkeepers (GK, n = 10), central defenders (CD, n = 23), full-backs (FB, n = 18), central midfielders (CM, n = 28), external midfielders (EM, n = 18), and forwards (FW, n = 11). Positional data (GPS; 10 Hz Polar Team Pro) and HR responses were collected. HRmean and HRpeak were 87%-89% and 98%-99% of HRmax, for outfield players, with no positional differences. CM, EM, and FB covered 8%-14% greater (P < .001) match distances than CD. EM, FW, FB, and CM performed 40%-64% more (P < .05) high-speed running and 41%-95% more (P < .01) very-high-speed running (VHSR) than CD. From the first to the last 15-minute period, total distance, except for FW, number of VHSR, except FB, peak speed and sum of accelerations and sum of decelerations decreased (P < .05) for all outfield positions. In the most intense 5-minute period, EM, FB, and CM performed 25%-34% more (P < .01) HSR than CD, whereas EM, FW, and FB performed 36%-49% more (P < .01) VHSR than CD. In conclusion, competitive elite female matches impose high physical demands on all outfield playing positions, with high aerobic loading throughout matches and marked declines in high-speed running and intense accelerations and decelerations toward the end of games. Overall physical match demands are much lower for central defenders than for the other outfield playing positions, albeit this difference is minimized in peak-intensity periods

The UEFA Heading Study: Heading incidence in children's and youth' football (soccer) in eight European countries

To assess the real‐life magnitude of the heading incidence in children's and youth’ football in eight European countries with different “football cultures,” a cross‐sectional observational design, in which one match per team in 480 different teams from eight European countries (2017/18‐2018/19), was recorded by video. One training session was recorded in 312 teams. Clubs with Under‐10, Under‐12 (female/male/mixed), and Under‐16 female and male teams were eligible to participate. Heading frequencies and types were analyzed. Results are presented as headers per match/training and per team. Incidence rates (IR) per 1000 match/training hours were calculated. Under‐10 teams carried out the lowest average number of headers per match (8.8), followed by Under‐16 female (17.7), Under‐12 (18.4), and Under‐16 male (35.5). Total number of headers per match and team varied between countries. 80% of the total number of headers were single intentional headers, 12% heading duels, 3% unintentional headers by getting hit, and 5% others (trends apparent in all age groups). Three head injuries occurred during match play corresponding to an IR of 0.70 (95% CI, 0.23‐2.16). The lowest number of headers per training and team was found in Under‐10 (21.3), followed by Under‐16 females (34.1), Under‐12 (35.8), and Under‐16 males (45.0). In conclusion, this large‐scale study presents novel data about the number and type of headers in youth’ football throughout Europe. A more precise understanding of the heading incidence, specifically in young players, is mandatory for the debate of restrictions on heading in youth football

The UEFA Heading Study:Heading incidence in children's and youth' football (soccer) in eight European countries

To assess the real-life magnitude of the heading incidence in children's and youth' football in eight European countries with different "football cultures" a cross-sectional observational design, in which one match per team in 480 different teams from eight European countries (2017/18-2018/19) was recorded by video. One training session was recorded in 312 teams. Clubs with Under-10, Under-12 (female/male/mixed) and Under-16 female and male teams were eligible to participate. Heading frequencies and types were analysed. Results are presented as headers per match/training and per team. Incidence rates (IR) per 1000 match/training hours were calculated. Under-10 teams carried out the lowest average number of headers per match (8.8), followed by Under-16 female (17.7), Under-12 (18.4), and Under-16 male (35.5). Total number of headers per match and team varied between countries. 80% of the total number of headers were single intentional headers, 12% heading duels, 3% unintentional headers by getting hit and 5% others (trends apparent in all age groups). Three head injuries occurred during match play corresponding to an IR of 0.70 (95% CI, 0.23-2.16). The lowest number of headers per training and team was found in Under-10 (21.3), followed by Under-16 females (34.1), Under-12 (35.8), and Under-16 males (45.0). In conclusion, this large-scale study presents novel data about the number and type of headers in youth' football throughout Europe. A more precise understanding of the heading incidence, specifically in young players, is mandatory for the debate of restrictions on heading in youth football

Fitness effects of 10-month frequent low-volume ball game training or interval running for 8-10-year-old school children

We investigated the exercise intensity and fitness effects of frequent school-based low-volume high-intensity training for 10 months in 8–10-year-old children. 239 Danish 3rd-grade school children from four schools were cluster-randomised into a control group (CON, n=116) or two training groups performing either 5×12 min/wk small-sided football plus other ball games (SSG, n=62) or interval running (IR, n=61). Whole-body DXA scans, flamingo balance, standing long-jump, 20 m sprint, and Yo-Yo IR1 children’s tests (YYIR1C) were performed before and after the intervention. Mean running velocity was higher (p<0.05) in SSG than in IR (0.88±0.14 versus 0.63±0.20 m/s), while more time (p<0.05) was spent in the highest player load zone (>2; 5.6±3.4 versus 3.7±3.4%) and highest HR zone (>90% HRmax; 12.4±8.9 versus 8.4±8.0%) in IR compared to SSG. After 10 months, no significant between-group differences were observed for YYIR1C performance and HR after 2 min of YYIR1C (HRsubmax), but median-split analyses showed that HRsubmax was reduced (p<0.05) in both training groups compared to CON for those with the lowest aerobic fitness (SSG versus CON: 3.2%  HRmax [95% CI: 0.8–5.5]; IR versus CON: 2.6%  HRmax [95% CI: 1.1–5.2]). After 10 months, IR had improved (p<0.05) 20 m sprint performance (IR versus CON: 154 ms [95% CI: 61–241]). No between-group differences (p>0.05) were observed for whole-body or leg aBMD, lean mass, postural balance, or jump length. In conclusion, frequent low-volume ball games and interval running can be conducted over a full school year with high intensity rate but has limited positive fitness effects in 8–10-year-old children