Different neuromuscular control mechanisms regulate static and dynamic balance: A center-of-pressure analysis in young adults

The analysis of the center of pressure (CoP) trajectory, derived from force platforms, is a widely accepted measure to investigate postural balance control. The CoP trajectory could be analyzed as a physiological time-series through a general stochastic modeling framework (i.e., Stabilogram Diffusion Analysis (SDA)). Critical point divides short-term from long-term regions and diffusion coefficients reflect the level of stochastic activity of the CoP. Sample Entropy (SampEn) allows quantifying the CoP complexity in terms of regularity. Thus, this study aimed to understand whether SDA and SampEn could discriminate the neuromuscular control mechanisms underpinning static and dynamic postural tasks. Static balance control and its relationship with dynamic balance control were investigated through the CoP velocity (Mean Velocity) and the area of the 95th percentile ellipse (Area95). Balance was assessed in 15 subjects (age: 23.13 ± 0.99 years; M = 9) over a force platform under two conditions: static (ST) and dynamic, both in anterior-posterior (DAP) and medio-lateral (DML) directions. During the DAP and DML, subjects stood on an unstable board positioned over a force platform. Short-term SDA diffusion coefficients and critical points were lower in ST than in DAP and DML (p < 0.05). SampEn values resulted greater in ST than in DAP and DML (p < 0.001). As expected, lower values of Area95 (p < 0.001) and Mean Velocity (p < 0.001) were detected in the easiest condition, the ST, compared to DAP and DML. No significant correlations between static and dynamic balance performances were detected. Moreover, differences in the diffusion coefficients were detected comparing DAP and DML (p < 0.05). In the anterior-posterior direction, the critical point occurred at relatively small intervals in DML compared to DAP (p < 0.001) and ST (p < 0.001). In the medio-lateral direction, the critical point differed only between DAP and DML (p < 0.05). Overall, SDA analysis pointed out a less tightly regulated neuromuscular control system in the dynamic tasks, with closed-loop corrective feedback mechanisms called into play at different time intervals in the three conditions. SampEn results reflected more attention and, thus, less automatic control mechanisms in the dynamic conditions, particularly in the medio-lateral task. The different neuromuscular control mechanisms that emerged in the static and dynamic balance tasks encourage using both static and dynamic tests for a more comprehensive balance performance assessment.     

Volitional step execution is an ineffective predictor of recovery performance after sudden balance loss across the age range

Rapid stepping to preserve stability is a crucial action in avoiding a fall. It is also an important measure in the assessment of fall-resisting skills. We examined whether volitional step execution correlates with recovery stepping performance after sudden balance loss for adults of different ages. In addition, we investigated whether volitional step performance can discriminate between individuals with high and low balance recovery capabilities, i.e. between those making single versus multiple steps after balance perturbation. Healthy adults (28 young, 43 middle-aged and 26 older; 24 ± 4, 52 ± 5 and 72 ± 5 years respectively) performed a single step in the anterior direction volitionally in response to a mechanical stimulus to the heel. In a second stepping task, participants experienced sudden anterior balance loss in a lean-and-release protocol. For both tasks, an optical motion capture system was used to assess stepping kinematics. We found on average 28% shorter reaction times, 46% faster maximal step velocities and 48% higher rates of increase in base of support across all participants after sudden balance loss compared to volitional stepping (p < 0.001). There was a significant age-related decline in recovery stepping performance after sudden balance loss: 24/26 older, 15/43 middle-aged and none of the younger adults required two or more steps to regain balance (p < 0.001). Multiple- compared to single-steppers had on average 23% shorter step lengths and 12% lower maximal step velocities for the lean-and-release task (p < 0.01). Multiple-steppers also had reduced rates of increase in base of support for both stepping tasks (14% for balance recovery and 11% for volitional stepping). Furthermore, in examining the relationship between the results of the two tasks, only weak to moderate correlations were observed for step velocity and rate of increase in base of support (0.36 ≤ r ≤ 0.52; p < 0.001). Thus, performance in volitional step execution has a low potential to explain variability in recovery response after sudden balance loss in adults across the lifespan and hence seems less suitable to be used to identify deficiencies in reactive stepping responses necessary to cope with sudden balance disturbances.     

Task specificity and neural adaptations after balance learning in young adults

BackgroundOnly 30 min of balance skill training can significantly improve behavioral and neuromuscular outcomes. However, it is unclear if such a rapidly acquired skill is also retained and transferred to other untrained balance tasks.Research questionWhat are the effects of a single balance training session on balance skill acquisition, retention, and transferability and on measures of neural plasticity examined by transcranial magnetic brain stimulation (TMS) and inter-muscular coherence?MethodsHealthy younger adults (n = 36, age 20.9, 18 M) were randomly assigned to: Balance training (BT); Active control (cycling training, CT) or non-active control (NC) and received a 20-min intervention. Before, immediately and ~ 7 days after the interventions, we assessed performance in the trained wobble board task, untrained static standing tasks and dynamic beam walking balance tasks. Underlying neural plasticity was assessed by tibialis anterior motor evoked potential, intracortical facilitation, short-interval intracortical inhibition and long-interval intracortical inhibition using TMS and by inter-muscular coherence.ResultsBT, but not CT (18%, d = 0.32) or NC (−1%, d = −0.02), improved balance performance in the trained, wobble board task by 207% (effect size d = 2.12). BT retained the acquired skill after a 1-week no-training period (136%, d = 1.57). No changes occurred in 4 measures of balance beam walking, in 8 measures of static balance, in 8 measures of intermuscular coherence, and in 4 TMS measures of supra-spinal plasticity (all p > 0.05).SignificanceHealthy young adults can learn a specific balance skill very rapidly but one should be aware that while such improvements were retained, the magnitude of transfer (32%, d = 0.94) to other balancing skills was statistically not significant. Additional studies are needed to determine the underlying neural mechanisms of rapid balance skill acquisition, retention, and transfer.     

Two years of physically active mathematics lessons enhance cognitive function and gross motor skills in primary school children

Physically active lessons have been shown to enhance academic achievement. However, the effects on cognitive function and gross motor skill development remain unknown. The present study examined how the incorporation of physical activity bouts within Mathematics lessons affects cognitive function and gross motor skill development across 2 years in primary school children. Eighty-two children (6.6 ± 0.3 y) were allocated to an intervention (n = 36; completing 8 h/wk of physically active lessons) or control (n = 46) group. A battery of cognitive function tests was completed, alongside the TGMD-3 to assess gross motor skills. Physically active Mathematics lessons led to greater improvements across all measures of cognition, when compared to the control group (digit span forwards, p < 0.001, d = 1.5; digit span backwards, p = 0.017, d = 1.0; free word recall: p < 0.001, d = 1.3; selective visual attention: p < 0.001, d = 0.3; verbal fluency: p < 0.001, d = 0.9; arithmetic: p < 0.001, d = 1.8). Furthermore, the intervention group demonstrated greater improvements in overall score on the TGMD-3 (p < 0.001, d = 1.7), as well as the locomotion (p < 0.001, d = 1.1) and object control (p < 0.001, d = 1.5) sub-scales. The physically active Mathematics lessons intervention appears to offer synergistic benefits in relation to cognitive and motor development, which are critical for optimal development in the early years.     

The predictive relationships between advanced dynamic balance and physical activity/quality of life in Parkinson's disease

Gait and balance problems commonly occur in Parkinson's disease (PD). However, balance tasks with only one performance objective (e.g., sit-to-stand) may not be sufficient, compared to dual motor tasks (e.g., carrying a tray while walking), to be applied to the assessments and interventions which are designed to promote PD patients' balance functioning, physical activity (PA) and health-related quality of life (HQoL). The aim of this study, therefore, was to determine whether advanced dynamic balance, measured by a demanding motor-motor dual task, is a significant predictor of PA/HQoL in older adults with and without PD. Participants with (n = 22) and without (n = 23) PD were assessed using the Berg Balance Scale (BBS), the single leg hop and stick series task (SLHS), the Physical Activity Scale for the Elderly (PASE), and the Parkinson's Disease Questionnaire–39 (PDQ39). We calculated the R² change, namely the incremental validity, between the multiple regression models before and after adding the scores on the BBS/SLHS. While controlling for biological and socioeconomic covariates, competence in the SLHS task provided moderate and large levels of incremental validity to PA (ΔR² = 0.08, Cohen's f² = 0.25, p = .035) and HQoL (ΔR² = 0.13, Cohen's f² = 0.65, p < .001), respectively. In particular for participants with PD, the SLHS explained significantly more variance in HQoL in relation to psychosocial functioning (ΔR² = 0.25, Cohen's f² = 0.42, p = .028) compared to the BBS (p = .296). Assessing advanced dynamic balance by means of a highly demanding dual-task paradigm was not only strongly associated with PA but also covered a wider spectrum of HQoL components. This approach is recommended for use in evaluations and interventions carried out in clinical and research settings in order to promote healthy living.     

The role of motion platform on postural instability and head vibration exposure at driving simulators

This paper explains the effect of a motion platform for driving simulators on postural instability and head vibration exposure. The sensed head level-vehicle (visual cues) level longitudinal and lateral accelerations (a_x,sensed = a_{x_head} and a_y,sensed = a_{y_head}, a_yv = a_{y_veh} and a_yv = a_{y_veh}) were saved by using a motion tracking sensor and a simulation software respectively. Then, associated vibration dose values (VDVs) were computed at head level during the driving sessions. Furthermore, the postural instabilities of the participants were measured as longitudinal and lateral subject body centre of pressure (X_CP and Y_CP, respectively) displacements just after each driving session via a balance platform. The results revealed that the optic-head inertial level longitudinal accelerations indicated a negative non-significant correlation (r = −.203, p = .154 > .05) for the static case, whereas the optic-head inertial longitudinal accelerations depicted a so small negative non-significant correlation (r = −.066, p = .643 > .05) that can be negligible for the dynamic condition. The X_CP for the dynamic case indicated a significant higher value than the static situation (t(47), p < .0001). The VDV_x for the dynamic case yielded a significant higher value than the static situation (U(47), p < .0001). The optic-head inertial lateral accelerations resulted a negative significant correlation (r = −.376, p = .007 < .05) for the static platform, whereas the optic-head inertial lateral accelerations showed a positive significant correlation (r = .418, p = .002 < .05) at dynamic platform condition. The VDV_y for the static case indicated a significant higher value rather than the dynamic situation (U(47), p < .0001). The Y_CP for the static case yielded significantly higher than the dynamic situation (t(47), p = .001 < 0.05).     

Manual disfluency in drawing while producing and listening to disfluent speech

This study investigated the extent to which manual fluency was associated with speech fluency in fluent speakers engaged in dual motor tasks. Thirteen right-handed adult females repeatedly drew circles with a pen on a digitizer tablet under five conditions: (1) a baseline (without reading or listening to speech), (2) reading fluently, (3) reading disfluently, (4) listening to fluent speech, and (5) listening to disfluent speech. The primary measure of disfluency was normalized mean squared jerk (NJ) in the pen strokes. Pen stroke time (ST) and pressure (PP) were also measured. NJ of the circle movements was significantly increased in both the disfluent reading and the disfluent listening conditions (p < 0.05), compared to the baseline condition. In the fluent listening and reading conditions, NJ in circle drawing was unaltered compared to the baseline condition. Relative to baseline, ST increased significantly (p < 0.05), but to a similar extent in all experimental conditions. Significantly (p < .05) greater pen pressure were also found in the disfluent versus fluent conditions. Positive correlations (r = 0.33–0.63) were found between NJ and ST across conditions. These findings demonstrate that in dual-tasks, speech fluency can influence manual fluency. This is consistent with the corpus of data showing neural connectivity between manual and speech tasks, as well between perception and production. The mirror neuron system is implicated as a mechanism involved in forging these links.     

Use of video observation and motor imagery on jumping performance in national rhythmic gymnastics athletes

The aim of this study was to evaluate whether a mental training protocol could improve gymnastic jumping performance. Seventy-two rhythmic gymnasts were randomly divided into an experimental and control group. At baseline, experimental group completed the Movement Imagery Questionnaire Revised (MIQ-R) to assess the gymnast ability to generate movement imagery. A repeated measures design was used to compare two different types of training aimed at improving jumping performance: (a) video observation and PETTLEP mental training associated with physical practice, for the experimental group, and (b) physical practice alone for the control group. Before and after six weeks of training, their jumping performance was measured using the Hopping Test (HT), Drop Jump (DJ), and Counter Movement Jump (CMJ). Results revealed differences between jumping parameters F(1, 71) = 11.957; p < .01, and between groups F(1, 71) = 10.620; p < .01. In the experimental group there were significant correlations between imagery ability and the post-training Flight Time of the HT, r(34) = −.295, p < .05 and the DJ, r(34) = −.297, p < .05. The application of the protocol described herein was shown to improve jumping performance, thereby preserving the elite athlete’s energy for other tasks.     

Prevalence,correlates, and psychosocial outcomes of sport participation in young adult cancer survivors

Young adult cancer survivors (YACS) face unique challenges from their disease and treatments that may influence their sport participation choices as well as their psychosocial response.ObjectivesTo examine the prevalence, correlates, and psychosocial outcomes of sport participation in YACS.DesignA provincial, population-based mailed survey of 588 YACS in Alberta, Canada, was completed in May 2008 and included measures of sport participation, psychosocial health (depression, self-esteem, and stress), quality of life (QoL), and medical and demographic variables.ResultsOne third (32.5%) of YACS reported participating in a sport in the past month with the most common being golf (40.8%) and ice hockey (8.3%). YACS participating in sport reported an average frequency of 1.7 (SD = 1.0) days/week and an average duration of 119 min/session (SD = 68) for a total of 189 (SD = 164) min/week. Independent t-tests showed that YACS who participated in sport reported better psychosocial health and QoL including physical QoL (p < 0.001), mental QoL (p < 0.001), self-esteem (p < 0.001), depression (p < 0.001), and stress (p < 0.001). In multivariate regression analysis, 8.5% (p < 0.001) of the variance in sport participation was explained by being male (β = 0.17, p < 0.001), Caucasian (β = 0.15, p = 0.001), in better general health (β = 0.15, p < 0.001), and having a normal body mass index (β = ?0.10, p = 0.024).Discussion/conclusionsSport participation is associated with better psychosocial health and QoL in YACS but only a third participated in the past month. Randomized controlled trials examining sport as an intervention strategy to increase physical activity and improve health outcomes in YACS are warranted.     

Communication profiles and sport experiences of collegiate track and field athletes

ObjectivesAthletes often communicate with one another and exchange information, attitudes, and feelings that can influence their sport experiences. In an effort to better understand the sport communication context, the purpose of the current study was to (a) describe communication profiles of athletes (b) examine potential predictors (i.e., team identity, sex) of profile membership, and (c) examine the salience of these profiles by assessing profile group differences on athletes’ perceptions of burnout, engagement, satisfaction, and enjoyment.DesignCross-sectional survey-based study.MethodCollegiate track and field athletes (N = 219) completed measures of demographic information, team communication, team identity, burnout, engagement, enjoyment, and satisfaction. Communication profiles were examined using latent profile analysis. Using the three-step method in Mplus, possible prediction of profile membership and profile differences in perceptions of sport experiences were examined.ResultsThree profiles emerged: the Less Effective Communicators, the Supportive Communicators, and the Functional Communicators. Athletes with greater team identity were more likely to be in the Supportive Communicators profile (p < 0.001), male participants were more likely to be in the Functional Communicators profile (p < 0.05) than the other profiles, and female participants were less likely to be in the Less Effective Communicators profile than the Supportive Communicators profile (p < 0.05). The Less Effective Communicators had greater perceptions of burnout (ps < 0.01) and lower perceptions of engagement (p < 0.01 and p < 0.05), satisfaction (p < 0.001 and p = 0.001), and enjoyment (p < 0.001 and p < 0.05) than the Supportive and Functional Communicators. Supportive Communicators had greater satisfaction (p < 0.001) and enjoyment (p < 0.001) than the Functional Communicators.ConclusionsDifferent profiles of communication in track and field athletes may have implications for athletes’ sport experiences and warrant continued study.     

The relationship between hip,knee and ankle muscle mechanical characteristics and gait transition speed

The purpose of the present study was to explore the relationship between mechanical characteristics of hip, knee and ankle extensor and flexor muscle groups and gait transition speed. The sample included 29 physically active male adults homogenized regarding their anthropometric dimensions. Isokinetic and isometric leg muscle mechanical characteristics were assessed by an isokinetic dynamometer, while individual walk-to-run (WRT) and run-to-walk transition speeds (RWT) were determined using the standard increment protocol. The relationship between transition speeds and mechanical variables scaled to body size was determined using Pearson correlation and stepwise linear regression. The highest correlations were found for isokinetic power of ankle dorsal flexors and WRT (r = .468, p < .01) and the power of hip extensors and RWT (r = .442, p < .05). These variables were also the best predictors of WRT and RWT revealing approximately 20% of explained variance. Under the isometric conditions, the maximal force and rate of force development of hip flexors and ankle plantar flexors were moderately related with WRT and RWT (ranged from r = .340 to .427). The only knee muscle mechanical variable that correlated with WRT was low velocity knee flexor torque (r = .366, p < .05). The results generally suggest that the muscle mechanical properties, such as the power of ankle dorsal flexors and hip extensors, influence values of WRT and RWT.     

The relationship between allometry and preferred transition speed in human locomotion

The purpose of this study was to explore the relationships between preferred transition speed (PTS) and anthropometric characteristics, body composition and different human body proportions in males. In a sample of 59 male students, we collected anthropometric and body composition data and determined individual PTS using increment protocol. The relationships between PTS and other variables were determined using Pearson correlation, stepwise linear and hierarchical regression. Body ratios were formed as quotient of two variables whereby at least one significantly correlated to PTS. Circular and transversal (except bitrochanteric diameter) body dimensions did not correlate with PTS. Moderate correlations were found between longitudinal leg dimensions (foot, leg and thigh length) and PTS, while the highest correlation was found for lower leg length (r = .488, p < .01). Two parameters related to body composition showed weak correlation with PTS: body fat mass (r = −.250, p < .05) and amount of lean leg mass scaled to body weight (r = .309, p < .05). Segmental body proportions correlated more significantly with PTS, where thigh/lower leg length ratio showed the highest correlation (r = .521, p < .01). Prediction model with individual variables (lower leg and foot length) have explained just 31% of PTS variability, while model with body proportions showed almost 20% better prediction (R² = .504). These results suggests that longitudinal leg dimensions have moderate influence on PTS and that segmental body proportions significantly more explain PTS than single anthropometric variables.     

Knowledge,Attitude, and Practice of Clerical Students with Respect to HIV/AIDS in Iran, 2011

In this study, knowledge and attitude of Iranian clerical students toward HIV and AIDS was assessed. Through a cross-sectional study, 367 clerical students were surveyed, in convenience sampling method, in the Qom seminary in 2011, utilizing a self-administered structured questionnaire. The questionnaire was piloted on 20 clerical student volunteers, internal consistency measured with Cronbach’s alpha was 0.89. Participants’ scores of knowledge and attitude were calculated out of 100. The level of knowledge in 37.33 % of participants was good (scores >80), whereas 46.05 and 16.62 % had moderate (40 < scores ≤ 80) and poor (scores ≤40) levels of knowledge, respectively. The mean score of knowledge and attitude was 58.29 (95 % CI 56.11–60) and 77.26 (95 % CI 75.92–78.59) out of 100, respectively. A significant correlation was observed between level of knowledge and attitude (r = 0.33, P < 0.001). Knowledge score appeared to be significantly higher in women compared to men (p = 0.04). With an increase in age, the level of knowledge significantly decreased (r = ?0.10, P = 0.02). We could also detect a statistically significant relationship between attending educational courses on HIV/AIDS and inclusion of HIV/AIDS topics in the individual’s sermons (P < 0.001). Although clerical students had shown some sort of positive attitudes toward HIV, their knowledge still needs to be improved to enable them to deliver more accurate information to the community during the course of their speeches. Having HIV-related courses as part of their curriculum or aside may contribute a lot to this.     

A new protocol for assessing action observation and imitation abilities in children with Developmental Coordination Disorder: A feasibility and reliability study

AIMS. To develop a new protocol for the assessment of action observation (AO) abilities and imitation of meaningful and non-meaningful gestures, to examine its psychometric properties in children with DCD and typically developing (TD) children. BACKGROUND. For learning manual skills, AO and imitation are considered fundamental abilities. Knowledge about these modalities in children with DCD is scarce and an assessment protocol is lacking. METHOD. The protocol consists of 2 tests. The AO test consists of two assembly tasks. The imitation test includes 12 meaningful and 20 non-meaningful gestures. Items of both tests are rated on a 4-point scale. Twelve children with DCD (mean age 8y3m, SD, 1.30) and 11 TD children (mean age 8y2m, SD 1.52) were enrolled. For inter-rater reliability, intraclass correlation coefficients (ICC) were calculated for the total score, weighted kappa and percentage agreement for single items. Known group validity was assessed by comparison of DCD and TD group (Wilcoxon rank sum test). For construct validity, the mABC-2 test was used. The protocol was adapted and confirmed by an intra and inter-rater reliability study (new sample of 11 DCD children, mean age 7y5m, SD 1.37). RESULTS. Excellent ICCs were reported for intra and inter-rater reliability for the final protocol. A significant difference between DCD and TD group was found for AO abilities (p < .01), for nonmeaningful gestures (p < .001). A significant correlation was reported between the AO test and the mABC-2 test (r = 56;p ≤0.0001). No significant correlations were revealed for the imitation tests. DISCUSSION AND CONCLUSION. The results support the psychometric properties of this protocol. When fully validated, it may contribute to map the deficits in AO abilities and imitation, to evaluate treatment effects of imitation and AO interventions.     

Age-related differences in the timing aspect of lumbopelvic rhythm during trunk motion in the sagittal plane

Forward bending and backward return of the human trunk in the sagittal plane are associated with a specific lumbopelvic rhythm, which consists of magnitude and timing aspects. In this study, the age-related differences in the timing aspect of lumbopelvic rhythm were investigated using the continuous relative phase method. Specifically, the mean absolute relative phase (MARP) between the thoracic and pelvic motions as well as variation in MARP under repetitive motions, denoted by deviation phase (DP), were characterized in sixty participants between 20 and 70 years old. MARP and DP were determined for trunk forward bending and backward return tasks with self-selected slow and fast paces. The MARP and DP were both smaller (p = 0.003, p < 0.001 respectively) in the older versus younger age participants with no gender-related difference. In fast versus slow pace task, the MARP was smaller (p < 0.001) only in forward bending, whereas the DP was smaller (p < 0.001) in both the forward bending and backward return. A more in-phase and more stable lumbopelvic rhythm denoted respectively by smaller MARP and DP in older versus younger individuals maybe a neuromuscular strategy to protect the lower back tissues from excessive strain, in order to reduce the risk of injury.     

Effect of an intensified training period on well-being indices,recovery and psychological aspects in professional soccer players

IntroductionIntensified training periods (IT) are associated with fatigue increase and psychological variations.ObjectiveThis investigation aimed to examine the perceived well-being, recovery quality and psychological responses during an IT.MethodsFifteen professional soccer players (mean ± SD: age: 24 ± 1 years, body mass: 71.3 ± 15.1 kg, height: 178.0 ± 6.1 cm) completed a 6-week training program consisting of 2 weeks of basic training (BT) and 4 weeks of IT. They were tested before (T1) and after (T2) the IT. Training load (TL) perception, strain and monotony were measured by the session-RPE method. Well-being indices (sleep quality, fatigue level, stress and delayed-onset muscular soreness [DOMS]) and total quality recovery (TQR) were recorded before each training session. The profile of mood states (POMS) and the Ottowa mental skills assessment tool (OMSAT)-3 were conducted before and after IT.ResultsNo significant difference was found after IT in OMSAT-3 scores (p > 0.05). TL, monotony and strain increased during IT (p < 0.001). Moreover, well-being indices (stress, sleep quality, fatigue level and DOMS) increased (p < 0.001) and TQR decreased (p < 0.001) during IT. The IT increased total mood disturbance (TMD, p < 0.001), tension (p < 0.05) and fatigue (p < 0.01) and decreased vigor (p < 0.001). Significant relationships were found between TL and Hooper Index (HI), TQR and TMD (r = 0.58, 0.65, −0.57, respectively; all p < 0.05).ConclusionThe findings of this investigation suggested that mental ability was not sensitive to fatigue caused by training load intensification. However, perceived well-being, recovery state and mood were found to be sensitive measures and may provide coaches with information about wellness and psychological state of soccer players during IT.     

The influence of the number of toys in the environment on toddlers’ play

We tested the hypothesis that an environment with fewer toys will lead to higher quality of play for toddlers. Each participant (n = 36) engaged in supervised, individual free play sessions under two conditions: Four Toy and Sixteen Toy. With fewer toys, participants had fewer incidences of toy play, longer durations of toy play, and played with toys in a greater variety of ways (Z = −4.448, p < 0.001, r = −0.524; Z = 2.828, p = 0.005, r = 0.333; and Z = 4.676, p < 0.001, r = 0.55, respectively). This suggests that when provided with fewer toys in the environment, toddlers engage in longer periods of play with a single toy, allowing better focus to explore and play more creatively. This can be offered as a recommendation in many natural environments to support children’s development and promote healthy play.     

Intelligence and semen quality are positively correlated

Human cognitive abilities inter-correlate to form a positive matrix, from which a large first factor, called ‘Spearman's g’ or general intelligence, can be extracted. General intelligence itself is correlated with many important health outcomes including cardio-vascular function and longevity. However, the important evolutionary question of whether intelligence is a fitness-related trait has not been tested directly, let alone answered. If the correlations among cognitive abilities are part of a larger matrix of positive associations among fitness-related traits, then intelligence ought to correlate with seemingly unrelated traits that affect fitness—such as semen quality. We found significant positive correlations between intelligence and 3 key indices of semen quality: log sperm concentration (r = .15, p = .002), log sperm count (r = .19, p < .001), and sperm motility (r = .14, p = .002) in a large sample of US Army Veterans. None was mediated by age, body mass index, days of sexual abstinence, service in Vietnam, or use of alcohol, tobacco, marijuana, or hard drugs. These results suggest that a phenotype-wide fitness factor may contribute to the association between intelligence and health. Clarifying whether a fitness factor exists is important theoretically for understanding the genomic architecture of fitness-related traits, and practically for understanding patterns of human physical and psychological health.     

Everyday tasks impair spatiotemporal variables of gait in older adults with Parkinson's disease

IntroductionAlthough it is known that individuals with Parkinson's disease (PD) have difficulties performing dual-task activities, most of the studies have verified the effect of dual tasks on gait using tasks that are uncommon to perform while walking. However, the realization of tasks involving gait that really represents the daily activities carried out by the participants, allow us to detect real fall risk situations of individuals with PD during their gait.ObjectiveOur aim was to verify the influence of daily-life dual-tasks on gait spatiotemporal variables of the older adults with PD.Methods20 older adults without PD and 20 older adults with PD participated in the study. Gait kinematic was analyzed under three different conditions: walking without dual task, walking carrying bags with weight, and walking talking on the cell phone.ResultsOlder adults with PD presented lower speed (p = .001), cadence (p = .039), and shorter step length (p = .028) than older adults without PD during walking without dual tasks. When walking while carrying bags with weight, older adults with PD had a lower speed (p < .001), cadence (p = .015), shorter step length (p = .008), and greater double support time (p = .021) compared with older adults without PD. During walking while talking on the cell phone, older adults with PD walked with lower speed (p < .001), cadence (p = .013), shorter step length (p = .001) and swing time (p = .013), and increased double support time (p = .008) and support time (p = .014) in relation to older adults without PD.ConclusionDaily-life dual tasks impair the spatiotemporal variables of gait in the older adults with PD, which was most evident during walking talking on the cell phone.     

Antenatal depressive symptoms are strongly predicted by the severity of pre-menstrual syndrome: results of partial least squares analysis

Background/Objective: Antenatal depression (AD) is the commonest morbidity during pregnancy. There is evidence that premenstrual syndrome (PMS) and AD share common immune-inflammatory and sex hormonal pathways. This study aims to evaluate the association between the severity of depressive PMS and AD in early and late pregnancy. Method: Participants were followed from early (<=16 weeks) to late pregnancy (>=20 weeks). The Premenstrual Symptoms Screening Tool (PSST) was used to assess PMS and AD symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS). Results: Up to 57.6% of the variance in the early EPDS score was explained by the regression on the first factor extracted from 10 depression and anxiety PSST items (dubbed the DepAnx PSST), insomnia PSST, relation dissatisfaction, and partner abuse. There were specific indirect effects of DepAnx PSST (p < 0.001), insomnia PSST (p = 0.041), relation dissatisfaction (p = 0.023) and partner abuse (p = 0.007) on the late EPDS which were mediated by the early EPDS score. Conclusion: The affective, but not psychosomatic, symptoms of PMS strongly predict AD symptoms suggesting that the pathophysiology of affective PMS symptoms overlap with those of AD.