Youth athletes are ideal candidates for novel therapeutic motor learning interventions that leverage the plasticity of the central nervous system to promote desirable biomechanical adaptions. We summarize the empirical data supporting the three pillars of the Optimizing Performance Through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning and expand on potential neurophysiologic mechanisms that will support enhanced movement mechanics in youth to optimize prevention programs for reduced injury risk, injury rehabilitation, exercise performance, and play (Prevention Rehabilitation Exercise Play; PREP). Specifically, we highlight the role of motivational factors to promote the release of dopamine that could accelerate motor performance and learning adaptations. Further, we detail the potential for an external focus of attention to shift attentional allocation and increase brain activity in regions important for sensorimotor integration to facilitate primary motor cortex efficiency. This manuscript serves to provide the most current data in support of the application of OPTIMAL PREP training strategies of the future.
Neuromuscular training aims to enhance motor skill competency and increase muscle strength. However, the effectiveness of short-duration interventions focused on addressing lower limb injury risk factors in male youth athletes at different stages of maturity remains unknown.
Forty-eight young male academy cricket players [pre-peak height velocity (PHV) (n = 26) and post-PHV (n = 22)] were subdivided into an experimental group (EXP) who completed a 4-week progressive neuromuscular training program and controls (CON) participating in sport training only. Changes in injury risk were examined using the Tuck Jump Assessment (TJA) and Landing Error Scoring System (LESS).
Total LESS score was significantly lower in both EXP maturity groups compared to CON following the 4-week program (10 to 6 and 6 to 4 (~ 20% to 40%)) in the pre- and post-PHV EXP groups, respectively. Significant within-group reductions in total LESS score were shown for the pre-PHV EXP group only (P < 0.05). Conversely, greater changes in TJA total score were shown in post-PHV (5 to 3; 40%) versus pre-PHV EXP (6 to 4.5; 26%). Pre-PHV players showed positive changes in individual LESS criteria indicative of frontal plane control but not in knee valgus during the TJA, whereas post-PHV players did improve this criterion.
This study indicates it is possible to reduce TJA and LESS scores in male youth athletes by performing a 4-week neuromuscular training program, improving landing mechanics and reducing injury risk irrespective of maturity, but their effects are somewhat influenced by stage of maturation and the task performed.
To examine the effects of a progressive injury prevention (IP) program, embedded into school curriculum, on injury rates in young females.
One hundred and three physical education (PE) students [mean ± SD; age = 14.0 ± 0.6 years; height = 162.6 ± 5.8 cm; mass = 57.4 ± 9.8 kg, intervention (INT) n = 53, control (CON) n = 50] from a girls’ secondary school participated in this study. The INT group (competitive athletes) completed a 23-week (three phase) IP program whereas the CON group continued normal PE class. An online questionnaire recorded training and competition exposure and self-reported injuries.
The INT group reported significantly more weekly training and competition hours than the CON group (4.15 ± 4.78 vs. 2.19 ± 3.22, P < 0.001 training hours and 0.77 ± 1.42 vs. 0.55 ± 1.10, P < 0.001 competition hours). There was no difference in any injury rate between the two groups. There was a significant reduction in injury rate between phase 1 and phase 3 of the IP program for the INT group [injury rate ratio = 0.63 (95% CI = 0.41–0.96); P = 0.02]. Injury rates in competition were higher than in training (40.1 and 36.3 injuries per 1000 h competition vs. 13.7 and 9.5 injuries per 1000 h training).
Although there was no difference in injury rates between groups, the IP program did significantly reduce rates with-in the INT group over the duration of the school year and may be protective against increased injury incidence for young females engaged in competitive sports.
To quantify the effects of an externally worn collar device for mitigating the influence of repetitive head impacts on alterations to diffusion tensor imaging (DTI) metrics of white matter.
Fifteen female high-school soccer athletes (age: 14.00–16.98 yrs) completed pre- and post-season DTI over two consecutive years, including measures of diffusivity, changes in which may be associated with brain dysfunction. The collar was worn during year 1 (Yr1) but not during year 2 (Yr2). Athlete exposures (AEs) and head impact exposure were recorded over the competitive seasons.
There were no significant differences in AEs or head impact exposures between Yr1 and Yr2 (P > 0.05). In Yr2, there was significant pre- to post-season mean diffusivity and/or axial diffusivity reduction in multiple WM regions (corrected P < 0.05). Pre- to post-season mean diffusivity, axial diffusivity, and radial diffusivity decreases were 3.04% ± 2.53%, 2.97% ± 2.19%, and 3.37% ± 3.34%, respectively, significantly greater than pre- to post-season changes in Yr1 (mean diffusivity: − 0.31% ± 1.78%, P = 0.0014; axial diffusivity: − 0.02% ± 2.25%, P = 0.0014; radial diffusivity: − 0.63% ± 2.10%, P = 0.0030).
Mild bilateral compression to athletes’ internal jugular vein through collar application may have increased intracranial blood volume and spatially redistributed head-impact-derived brain energy absorption. However, future research is needed to elucidate the potential clinical significance of WM changes of various degrees.
NCT03014492.
Sled towing has been shown to be an effective method to enhance the physical qualities in youth athletes. The aim of this study was to evaluate the impact of a 6-week sled towing intervention on muscular strength, speed and power in elite youth soccer players of differing maturity status.
Seventy-three male elite youth soccer players aged 12–18 years (Pre-Peak Height Velocity [PHV] n = 25; Circa-PHV n = 24; Post-PHV n = 24) from one professional soccer academy participated in this study. Sprint assessments (10 m and 30 m), countermovement jump and isometric mid-thigh pull were undertaken before (T1) and after (T2) a 6-week intervention. The training intervention consisted of 6 weeks (2 × per week, 10 sprints over 20 m distance) of resisted sled towing (linear progression 10%–30% of body mass) during the competitive season. Bayesian regression models analysed differences between T1 and T2 within each maturity group.
There were minimal changes in strength, speed and power (P = 0.35–0.80) for each maturity group across the 6-week intervention. Where there were changes with greater certainty, they are unlikely to represent real effect due to higher regression to the mean (RTM).
It appears that a 6-week sled towing training programme with loadings of 10%–30% body mass only maintains physical qualities in elite youth soccer players pre-, circa-, and post-PHV. Further research is required to determine the effectiveness of this training method in long-term athletic development programmes.
This study examined changes in vertical jump performance with progressively greater eccentric pre-loading in relation to growth and development in young female athletes.
Twenty young female athletes ranging from 9 to 17 years old performed the following vertical jumps in random order: static jumps (SJs), counter-movement jumps (CMJs), and drop jumps (DJs) from drop heights of 20, 30, and 40 cm (DJ20, DJ30, and DJ40, respectively). Measurements included peak force (PF), peak rate of force development (RFD), peak power (PP), eccentric impulse (ECC), and concentric impulse (CON). Measurements of growth included age, maturity offset, height, body mass, fat-free mass, and thigh muscle cross-sectional area (CSA).
PF increased from the SJ-DJ20 (P ≤ 0.009), then plateaued from DJ20-DJ40 (P = 1.000). RFD remained the same from SJ-CMJ (P = 1.000), increased from CMJ-DJ20 (P < 0.001), and plateaued from DJ20-DJ40 (P = 0.874). PP increased from the SJ-CMJ (P < 0.001), then plateaued from the CMJ-DJ40 (P ≥ 0.486). CON remained the same across all vertical jumps (P = 1.000), while ECC increased from the SJ-DJ40 (P ≤ 0.038). Jump height (JH) increased from the SJ-CMJ (P < 0.001), decreased from CMJ-DJ20 (P < 0.001), and plateaued from DJ20-DJ40 (P = 1.000). The change in PP from the SJ-CMJ (ΔCMJ-SJ) was related to all measurements of growth except CSA (r = 0.558–0.815).
Young females produced greater power during the CMJ than SJ, but equivalent power from the CMJ-DJ40, despite increases in ECC. Additionally, ΔCMJ-SJ was not related to CSA, which suggests other underlying mechanisms affect stretch–shortening cycle utilization in young female athletes.