Anterior cruciate ligament (ACL) injury risk reduction strategies primarily focus on biomechanical factors related to frontal plane knee motion and loading. Although central nervous system processing ...has emerged as a contributor to injury risk, brain activity associated with the resultant ACL injury-risk biomechanics is limited. Thus, the purposes of this preliminary study were to determine the relationship between bilateral motor control brain activity and injury risk biomechanics and isolate differences in brain activity for those who demonstrate high versus low ACL injury risk. Thirty-one high school female athletes completed a novel, multi-joint leg press during brain functional magnetic resonance imaging (fMRI) to characterize bilateral motor control brain activity. Athletes also completed an established biomechanical assessment of ACL injury risk biomechanics within a 3D motion analysis laboratory. Knee abduction moments during landing were modelled as a covariate of interest within the fMRI analyses to identify directional relationships with brain activity and an injury-risk group classification analysis, based on established knee abduction moment cut-points. Greater landing knee abduction moments were associated with greater lingual gyrus, intracalcarine cortex, posterior cingulate cortex and precuneus activity when performing the bilateral leg press (all z > 3.1, p < .05; multiple comparison corrected). In the follow-up injury-risk classification analysis, those classified as high ACL injury-risk had greater activity in the lingual gyrus, parietal cortex and bilateral primary and secondary motor cortices relative to those classified as low ACL injury-risk (all z > 3.1, p < .05; multiple comparison corrected). In young female athletes, elevated brain activity for bilateral leg motor control in regions that integrate sensory, spatial, and attentional information were related to ACL injury-risk landing biomechanics. These data implicate crossmodal visual and proprioceptive integration brain activity and knee spatial awareness as potential neurotherapeutic targets to optimize ACL injury-risk reduction strategies.
Numerous efforts have been made to test the OPTIMAL theory of motor learning in healthy children and adult populations. However, only a small number of studies have tested this theory in children ...with cognitive-motor disorders, such as developmental coordination disorder (DCD). The present study aims to examine the individual and additive effects of a visual illusion and self-controlled practice on a golf putting task in children at risk for DCD based on the OPTIMAL theory. Forty children at risk for DCD (mean age = 8.57 ± 1.05 years) were randomly assigned to four experimental groups (1-small visual illusion + self-controlled practice; 2-big visual illusion + self-controlled practice; 3-small visual illusion + yoked; 4-big visual illusion + yoked). Following 12 pretest trials of a golf putting task, the participants completed 5 blocks of 12 trials of practice on the first day. A retention test (12 trials) and a transfer dual-task test (12 trials) were conducted on the second day. The results indicated that in retention test the big visual illusion + self-controlled practice group was significantly better than the small visual illusion + yoked group (p = 0.01), while there was not any other significant difference between groups at retention test as well as between all groups at practice phase and transfer test (p > 0.05 for all comparisons). In other words, an additive effect has been observed just in the retention test but not the practice phase as well as transfer test. In general, the results of this study support the OPTIMAL theory of motor learning in children at risk for DCD and suggests to all educators who work with these children to use the combination of the visual illusion with self-controlled practice to improve the motor learning of children at risk for DCD.
Bilateral sensorimotor coordination is required for everyday activities, such as walking and sitting down/standing up from a chair. Sensorimotor coordination functional neuroimaging (fMRI) paradigms ...(e.g., stepping, cycling) increase activity in the sensorimotor cortex, supplementary motor area, insula, and cerebellum. Although these paradigms are designed to assay coordination, performance measures are rarely collected simultaneously with fMRI. Therefore, we aimed to identify neural correlates of lower extremity coordination using a bilateral, in‐phase, multi‐joint coordination task with concurrent MRI‐compatible 3D motion analysis. Seventeen female athletes (15.0 ± 1.4 years) completed a bilateral, multi‐joint lower‐extremity coordination task during brain fMRI. Interlimb coordination was quantified from kinematic data as the correlation between peak‐to‐peak knee flexion cycle time between legs. Standard preprocessing and whole‐brain analyses for task‐based fMRI were completed in FSL, controlling for total movement cycles and neuroanatomical differences, with interlimb coordination as a covariate of interest. A clusterwise multi‐comparison correction was applied at z > 3.1 and p < .05. Less interlimb coordination during the task was associated with greater activation in the posterior cingulate and precuneus (zmax = 6.41, p < .01) and the lateral occipital cortex (zmax = 7.55, p = .02). The inability to maintain interlimb coordination alongside greater activity in attention‐ and sensory‐related brain regions may indicate a failed compensatory neural strategy to execute the task. Alternatively, greater activity could be secondary to reduced afferent acuity that may be elevating central demand to maintain in‐phase lower extremity motor coordination. Future research aiming to improve sensorimotor coordination should consider interventional approaches uniquely capable of promoting adaptive neuroplasticity to enhance motor control.
In the first report of a bilateral lower extremity, in‐phase, multi‐joint coordination fMRI motor paradigm with concurrent kinematics, we found that lower extremity coordination was negatively associated with neural activity in the posterior cingulate gyrus, precuneus, and lateral occipital cortex; such that poorer coordination is associated with greater activity. This alteration may indicate a failed compensatory strategy to maintain motor control or higher central demand downstream from reduced afferent acuity.
The aims of this study were to (1) to explore attentional strategies in expert judo players and (2) investigate how attentional focus affects performance effectiveness and perceptions of workload in ...expert judo players during real competitions. Fourteen expert male judo players participated in the study. A simulated recall method was used following participants' competition to explore contents of attention qualitatively. The data analysis process for the qualitative portion of the study was an iterative process between inductive and deductive analyses. Quantitative analyses of performance outcomes and workload were then associated with the qualitative findings. Qualitative results revealed that the focus of attention was dynamic and complex, with technical aspects of the movements as the highest identified focus. Quantitative analyses revealed that reporting a lower quantity of attentional cues and higher percentage of focus on opponent resulted in higher performance effectiveness and less perceptions of workload. This study indicates that cognitive control and automaticity may work in a synergistic manner for successful skill execution in expert performance.
•We showed a simple manipulation of verbal cues affected performance accuracy in Fitts’ Law task.•Directing attention to an intended effect improved performance accuracy relative to directing ...attention to body movements.•Body-oriented attention affected performance when subjects’ attention was directed to a ‘virtual’ body.
The effects of attentional focus (AF) instruction were examined in a reciprocal aiming task implemented in a 3-dimensional, fully immersive virtual environment (VE). Within the VE, participants (N = 19) moved a cube between two targets at two paces (750 ms and 500 ms) while being asked to focus externally (EXF) and internally (INF). Performance accuracy was measured as two-dimensional error and its variability between the center of the target to the center of the cube and one-dimensional bias (undershooting/overshooting behavior in the anteroposterior and mediolateral directions). The results indicated better performance, specifically greater accuracy and lower one-dimensional bias in the anteroposterior direction when adopting an EXF compared to an INF. Our findings reveal that the beneficial effects of an EXF on motor performance are not restricted movements within physical environments only but also work in VE. This has implications for rehabilitation and training protocols in VE.
Falls in older adults are a public health challenge due to their influence on well-being and health-care costs. One way to address this challenge is to discover new methods to enhance postural ...control in older adults so they are better prepared to maintain an upright stance. Older and younger adults (N = 32) performed a static balance task on a force plate with no instructions, internal focus instructions, or external focus instructions. Center of pressure displacement time series were analyzed using sample entropy and standard deviation. Only the external focus condition significantly increased postural control entropy, which was observed across both age groups. This study showed that an external focus of attention can be used to increase postural control entropy within a single session of testing.
Persistent gait alterations can occur after concussion and may underlie future musculoskeletal injury risk. We compared dual-task gait stability measures among adolescents who did/did not sustain a ...subsequent injury post-concussion, and uninjured controls. Forty-seven athletes completed a dual-task gait evaluation. One year later, they reported sport-related injuries and sport participation volumes. There were three groups: concussion participants who sustained a sport-related injury (n = 8; age =15.4 ± 3.5 years; 63% female), concussion participants who did not sustain a sport-related injury (n = 24; 14.0 ± 2.6 years; 46% female), and controls (n = 15; 14.2 ± 1.9 years; 53% female). Using cross-recurrence quantification, we quantified dual-task gait stability using diagonal line length, trapping time, percent determinism, and laminarity. The three groups reported similar levels of sports participation (11.8 ± 5.8 vs. 8.6 ± 4.4 vs. 10.9 ± 4.3 hours/week;
= 0.37). The concussion/subsequent injury group walked slower (0.76 ± 0.14 vs. 0.65 ± 0.13 m/s;
= 0.008) and demonstrated higher diagonal line length (0.67 ± 0.08 vs. 0.58 ± 0.05;
= 0.02) and trapping time (5.3 ± 1.5 vs. 3.8 ± 0.6;
= 0.006) than uninjured controls. Dual-task diagonal line length (hazard ratio =1.95, 95% CI = 1.05-3.60), trapping time (hazard ratio = 1.66, 95% CI = 1.09-2.52), and walking speed (hazard ratio = 0.01, 95% CI = 0.00-0.51) were associated with subsequent injury. Dual-task gait stability measures can identify altered movement that persists despite clinical concussion recovery and is associated with future injury risk.
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•Female adolescent athletes experience variable exposure to head impacts.•An fMRI bilateral motor control task was used to evaluate changes in neural activity.•Exposure to high ...magnitude impacts altered neural activity following a soccer season.•Cognitive, motor, and visual changes were associated with high magnitude impacts.
Contact and collision sport participation among adolescent athletes has raised concerns about the potential negative effects of cumulative repetitive head impacts (RHIs) on brain function. Impairments from RHIs and sports-related concussions (SRC) may propagate into lingering neuromuscular control. However, the neural mechanisms that link RHIs to altered motor control processes remain unknown. The purpose of this study was to isolate changes in neural activity for a lower extremity motor control task associated with the frequency and magnitude of RHI exposure. A cohort of fifteen high school female soccer players participated in a prospective longitudinal study and underwent pre- and post-season functional magnetic resonance imaging (fMRI). During fMRI, athletes completed simultaneous bilateral ankle, knee, and hip flexion/extension movements against resistance (bilateral leg press) to characterize neural activity associated with lower extremity motor control. RHI data were binned into continuous categories between 20 g − 120 g (defined by progressively greater intervals), with the number of impacts independently modeled within the fMRI analyses. Results revealed that differential exposure to high magnitude RHIs (≥90 g - < 110 g and ≥ 110 g) was associated with acute changes in neural activity for the bilateral leg press (broadly inclusive of motor, visual, and cognitive regions; all p < 0.05 & z > 3.1). Greater exposure to high magnitude RHIs may impair lower extremity motor control through maladaptive neural mechanisms. Future work is warranted to extend these mechanistic findings and examine the linkages between RHI exposure and neural activity as it relates to subsequent neuromuscular control deficits.
Few studies have investigated the effect of external loads secured inferior to the center of mass (COM) on postural control and motor performance in younger and older adults. In the present study, we ...investigated the effect of systematically increased external loads secured inferior to the COM on young (N = 15, age years: M = 26.67, SD= 3.45) and older adults' (N = 15, age years: M = 67.4, SD= 7.69) center of pressure displacement and velocity, and also dart throwing performance in four different load conditions: 1) no load (control condition), 2) loading with 5% of body mass, 3) loading with 10% of body mass, and 4) loading with 20% of body mass. Overall, older adults had higher COP displacement and velocity in both anterior/posterior (AP) and Medio-lateral (ML) directions and poorer dart throwing scores than younger adults. Despite no significant difference in dart throwing performance for the different load conditions within each age group, loading with 10% and 20% of body mass reduced AP COP displacement relative to control for both study groups, with 20% body mass also reducing AP COP velocity relative to control for both study groups. In conclusion the present findings reveal that external loads secured inferior to older and younger adults' COM may enhance postural control without compromising motor performance. The findings were discussed in the context of fall-prevention and athletic performance.
To determine factors associated with localized anterior arthrofibrosis (cyclops lesion), such as graft size, warranting early reoperation for lysis of adhesions after anterior cruciate ligament ...reconstruction (ACLR) with all–soft tissue quadriceps tendon (ASTQT) autograft.
All primary ASTQT autograft ACLRs within a single surgeon’s prospectively collected registry with minimum 6-month follow-up were included. Patients who underwent multiligament knee reconstruction or cartilage restoration procedures were excluded. Localized anterior arthrofibrosis was defined as the requirement for a second procedure to achieve debridement and lysis of adhesions owing to the inability to regain terminal extension within 6 months of ACLR. The sex-specific incidence of arthrofibrosis was evaluated relative to age, weight, femoral and tibial tunnel sizes, meniscal repair, and meniscectomy by a binary logistic regression.
This study included 721 patients (46% female patients). There were 52 cases of localized anterior arthrofibrosis (7.2%). Female patients had a greater incidence of arthrofibrosis than male patients. Male patients with a femoral tunnel diameter of 9.25 mm or greater had an increased incidence of arthrofibrosis compared with those with a diameter of less than 9.25 mm, whereas a similar cutoff was not found to be statistically significant for female patients. Concomitant meniscal repair was associated with an increased risk of arthrofibrosis.
Female sex and concomitant meniscal repair were associated with an increased localized anterior arthrofibrosis incidence. Furthermore, ASTQT with a femoral tunnel diameter of 9.25 mm or greater in male patients was associated with an increased incidence of arthrofibrosis.
Level III, retrospective, comparative prognostic trial.
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