Change in general and domain-specific physical activity during the transition from primary to secondary education: a systematic review.

BACKGROUND: Knowledge of changes in the domains of physical activity (PA) during the transition period from primary to secondary education and the factors associated with these changes, are prerequisites for the design of effective PA promotion strategies. Therefore, the first aim of this study was to systematically review changes in general, leisure-time, school, transport, work, and home PA across the transition from primary to secondary education. The second aim was to systematically review the individual, social, and physical environmental factors that were associated with these changes. METHODS: Records published up until September 2023 were retrieved from five electronic databases. We included longitudinal and cross-sectional studies that investigated general or domain-specific PA from 2 years before to 2 years after the transition from primary to secondary education. Information on source, study characteristics, sample characteristics, PA, and factors were extracted from the papers included. We reported the direction of change in general and domain-specific PA and the direction of association of the factors with change in general and domain-specific PA. RESULTS: Forty-eight papers were included in the study. The evidence on changes in PA and associated factors was greatest for general PA. A limited number of the studies investigated the separate domains of leisure-time, school, and transport. Most studies on general and school PA reported a decline in PA, but there were no consistent results for the domains of leisure-time and transport. With respect to the associated factors, evidence was predominantly found for individual factors and to a lesser degree for physical environmental and social environmental factors. None of the factors were consistently associated with changes in general or domain-specific PA during the school transition. CONCLUSIONS: For the design of targeted PA promotion strategies, further studies are warranted to explore changes in the specific domains of PA across the transition from primary to secondary education, especially in the domains of leisure-time, transport, home, and work PA. In addition, the interactions between factors at different socioecological levels to influence changes in PA need to be addressed more in the future. TRIAL REGISTRATION: PROSPERO CRD42020190204.

An early start at a professional soccer academy is no prerequisite for world cup soccer participation.

Introduction: 829 players from 32 nations on five continents participated in the 2022 men's World Cup tournament in Qatar. Not much is known about the youth careers of World Cup players from all over the world, especially about the age at which they began playing youth soccer in a professional academy. This study aimed to provide insights in the age national team players participating in World Cup Qatar 2022 started playing for a professional soccer academy and whether their starting age relates to continent and their current playing position (i.e., goalkeepers, defenders, midfielders, and forwards). Method: Systematic online desk research was conducted to determine the age at which World Cup players started playing for professional youth soccer organizations. The median and interquartile ranges were expressed for the starting age in professional youth soccer organizations and the current age at the World Cup. The variables were compared with playing position, the continent of the player's World Cup nation, and the continent on which the player was raised. Results: The results reveal that World Cup Qatar 2022 players started playing for professional soccer academies at a median age of 13.2 years (range: 4.2-22.6). In Europe, players started playing for professional youth soccer organizations earlier than players on other continents [χ2 (4) = 142.0, p < 0.001]. We also found a younger starting age in forwards than goalkeepers (p < 0.05). Discussion: In most established soccer nations in Europe and South-America, World Cup players started playing for professional soccer academies before the age of 12. However, a significant number of players started later, especially players on other continents, which reveals the different pathways youth players can follow to the elites.

Factors Related to Adolescents' Participation in Organized Sports.

Participation in organized sports has important health benefits in adolescence, yet participation rates are concerning. A better understanding of factors influencing adolescents' participation in organized sports offers opportunities to improve participation rates. The aim of this study was to examine to what extent motives, perceived competence, encouragement and motor skills were associated with participation in organized sports in a sample of first-year secondary school students. In this cross-sectional study, data were collected from 386 Dutch adolescents (11-14 years) in October and November 2020. A series of multilevel logistic regression models estimated the likelihood of adolescents' participating in organized sports. First, we examined whether motives, perceived competence, encouragement and motor skills were independently associated with the likelihood of participation. Second, we examined whether these factors were concurrently associated with the likelihood of participation. When considered individually, motives, perceived competence, encouragement and motor skills were significantly associated with participation. When considered together, only motives were significantly associated with participation and the associations of all other factors with sport disappeared. These findings show the importance of motivation for participation in sports over other factors. These findings inform the development of interventions aimed at improving adolescents' participation rates.

The impact of beetroot juice supplementation on muscular endurance, maximal strength and countermovement jump performance.

Purpose: Dietary nitrate has been shown to enhance muscle contractile function and has, therefore, been linked to increased muscle power and sprint exercise performance. However, the impact of dietary nitrate supplementation on maximal strength, performance and muscular endurance remains to be established. Methods: Fifteen recreationally active males (25 ± 4 y, BMI 24 ± 3 kg/m2) participated in a randomized double-blinded cross-over study comprising two 6-d supplementation periods; 140 mL/d nitrate-rich (BR; 985 mg/d) and nitrate-depleted (PLA; 0.37 mg/d) beetroot juice. Three hours following the last supplement, we assessed countermovement jump (CMJ) performance, maximal strength and power of the upper leg by voluntary isometric (30° and 60° angle) and isokinetic contractions (60, 120, 180 and 300°·s-1), and muscular endurance (total workload) by 30 reciprocal isokinetic voluntary contractions at 180°·s-1. Results: Despite differences in plasma nitrate (BR: 879 ± 239 vs. PLA: 33 ± 13 µmol/L, P < 0.001) and nitrite (BR: 463 ± 217 vs. PLA: 176 ± 50 nmol/L, P < 0.001) concentrations prior to exercise testing, CMJ height (BR: 39.3 ± 6.3 vs. PLA: 39.6 ± 6.3 cm; P = 0.39) and muscular endurance (BR: 3.93 ± 0.69 vs. PLA: 3.90 ± 0.66 kJ; P = 0.74) were not different between treatments. In line, isometric strength (P > 0.50 for both angles) and isokinetic knee extension power (P > 0.33 for all velocities) did not differ between treatments. Isokinetic knee flexion power was significantly higher following BR compared with PLA ingestion at 60°·s-1 (P = 0.001), but not at 120°·s-1 (P = 0.24), 180°·s-1 (P = 0.066), and 300°·s-1 (P = 0.36). Conclusion: Nitrate supplementation does not improve maximal strength, countermovement jump performance and muscular endurance in healthy, active males.

Teachers' perceptions of children's sport learning capacity predicts their fundamental movement skill proficiency.

The intrapersonal mechanism that drives and explains individual differences in motor development is still a relatively underexplored area of research. In this study, we set out to determine whether in teachers' perceptions, higher sport-learning capacity (SLC) is associated with the level of fundamental movement skills, and the changes therein over 24 weeks in 7-year-olds. We assessed 170 children from eight primary schools in the Netherlands twice (T1, T2) in 24 weeks, using a tool to assess their FMS in applied settings (Platvoet, Elferink-Gemser, & Visscher, 2018). The schools' eight PE teachers used a digital questionnaire to score their perceptions of children's SLC (Platvoet, Elferink-Gemser, Baker, & Visscher, 2015). Based on their SLC, each child was then placed in the low (n = 33), average (n = 107), or high SLC-group (n = 30). We used a MANOVA to examine group differences, with the four subtests as dependent variables. The results revealed that regardless of SLC-group, children improved their FMS over 24 weeks (F(4,163) = 10.22, p < .05, Wilks Lamba = 0.800). An interaction effect was found for FMS assessment and SLC-group (F(8,326) = 2.23, p < 0,05, Wilks Lamba = 0.899). The children in the average and high groups improved more on the moving sideways subtest than those in the low group (p < .05). The MANOVA showed a main effect for SLC-group (F(4,163) = 4.69, p < .05, Wilks Lamba = 0.804). The average and high groups outperformed the low group on the measurements for walking backwards and moving sideways (p < .05). The high group also outperformed the low group on jumping sideways at both measurements, while the average group only achieved this at T1. The high group scored better on jumping sideways than the average group at T1 (p < .05). No differences in proficiency were found between the three groups on the hand-eye coordination assessment (p > .05). In sum, we found an association between children's SLC and level of FMS and changes therein; this was especially pronounced in children with a lower SLC, who had a lower proficiency and improved less on the subtest moving sideways.

Four Weeks of Goal-Directed Learning in Primary Physical Education Classes.

Relatively little is known about how practice relates to children's improvement in gross motor skill performance. The aim of this study is to determine to what extent 6- and 7-year-old children improve their gross motor skill performance in a four-week period, in which goal-directed learning is stimulated and to determine whether differences between boys and girls occur. Groups of 6 year olds (n = 167) and 7 year olds (n = 140) practiced their gross motor skill for four weeks. Physical education teachers stimulated goal-directed learning by their instruction, skill-specific exercises, and individual practice. The week before and after, gross motor skill performance was assessed, using the Körper Koordinations Test für Kinder, and compared with a control group (n = 131). Both 6 and 7 year olds in the intervention group improved their gross motor skill performance significantly more than the control group. The results show the relevance of goal-directed learning for the improvement of gross motor skill performance.

Functional effects of botulinum toxin type-A treatment and subsequent stretching of spastic calf muscles: a study in patients with hereditary spastic paraplegia.

OBJECTIVE: Although calf muscle spasticity is often treated with botulinum toxin type-A, the effects on balance and gait are ambiguous. Hereditary spastic paraplegia is characterized by progressive spasticity and relatively mild muscle weakness of the lower limbs. It is therefore a good model to evaluate the functional effects of botulinum toxin type-A. DESIGN: Explorative pre-post intervention study. SUBJECTS: Fifteen subjects with pure hereditary spastic paraplegia. METHODS: Patients with symptomatic calf muscle spasticity and preserved calf muscle strength received botulinum toxin type-A injections in each triceps surae (Dysport®, 500-750 MU) followed by daily stretching exercises (18 weeks). Before intervention (T0), and 4 (T1) and 18 (T2) weeks thereafter, gait, balance, motor selectivity, calf muscle tone and strength were tested. RESULTS: Mean comfortable gait velocity increased from T0 (0.90 m/s (standard deviation (SD) 0.18)) to T1 (0.98 m/s (SD 0.20)), which effect persisted at T2, whereas balance and other functional measures remained unchanged. Calf muscle tone declined from T0 (median 2; range 1-2) to T1 (median 0; range 0-1), which effect partially persisted at T2 (median 1; range 0-2). Calf muscle strength did not change. CONCLUSION: Botulinum toxin type-A treatment and subsequent muscle stretching of the calves improved comfortable gait velocity and reduced muscle tone in patients with hereditary spastic paraplegia, while preserving muscle strength. Balance remained unaffected.

From sedentary time to sedentary patterns: accelerometer data reduction decisions in youth.

AIM: This study aims to establish evidence-based accelerometer data reduction criteria to accurately assess total sedentary time and sedentary patterns in children. METHODS: Participants (n = 1057 European children; 9-13 yrs) were invited to wear an accelerometer for at least 6 consecutive days. We explored 1) non-wear time criteria; 2) minimum daily valid wear time; 3) differences between weekday and weekend day; and 4) minimum number of days of accelerometer wear by comparing the effects of commonly used data reduction decisions on total sedentary time, and duration and number of prolonged sedentary bouts. RESULTS: More than 60 consecutive minutes of zero counts was the optimal criterion for non-wear time. Increasing the definition of a valid day from 8 to 10 hours wear time hardly influenced the sedentary outcomes, while the sample size of children with more than 4 valid days increased from 69 to 81%. On weekdays, children had on average 1 hour more wear time, 50 minutes more total sedentary time, 26 minutes more sedentary time accumulated in bouts, and 1 more sedentary bout. At least 6 days of accelerometer data were needed to accurately represent weekly sedentary time and patterns. CONCLUSIONS: Based on our results we recommend 1) a minimum of 60 minutes of consecutive zeros as the most realistic criterion for non-wear time; and 2) including at least six days with minimum eight valid hours to characterize children's usual total sedentary time and patterns, preferably including one weekend day.

StartReact restores reaction time in HSP: evidence for subcortical release of a motor program.

Startling acoustic stimuli (SAS) can accelerate reaction times ("StartReact" effect), but the underlying mechanism remains unclear. Both direct release of a subcortically stored motor program and a subcortically mediated trigger for a cortically stored motor program have been hypothesized. To distinguish between these hypotheses, we examined the StartReact effect in humans with pure hereditary spastic paraplegia (HSP). Delayed reaction times in HSP patients in trials both with and without a SAS would argue in favor of a cortically stored response. We instructed 12 HSP patients and 12 matched controls to respond as rapidly as possible to a visual imperative stimulus, in two different conditions: dorsiflexion of the dominant ankle; or flexion of the dominant wrist. In 25% of trials, a SAS was delivered simultaneously with the imperative stimulus. Before these tests, subjects received five SAS while standing to verify normal function of the reticulospinal tract in HSP. Latencies of startle responses in sternocleidomastoid and tibialis anterior muscles were comparable between patients and controls. During the ankle dorsiflexion task, HSP patients had an average 19 ms delay in reaction times compared with controls. Administration of a SAS accelerated ankle dorsiflexion in both groups, but more so in the patients, which completely normalized their latencies. The wrist flexion task yielded no differences in onset latencies between HSP patients and controls. The reticulospinal tract seems unaffected in HSP patients, because startle reflex onsets were normal. The corticospinal tract was affected, as reflected by delayed ankle dorsiflexion reaction times. These delayed onsets in HSP were normalized when the imperative stimulus was combined with a SAS, presumably through release of a subcortically stored motor program conveyed by the preserved reticulospinal tract.

Mechanisms of postural instability in hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP) is characterized by progressive lower extremity spasticity and weakness, due to retrograde axonal degeneration of the corticospinal tract and posterior spinal columns. HSP patients fall frequently. We hypothesized that delayed postural responses contribute to their balance impairments. To distinguish between a delay in afferent and efferent signals, we combined postural responses with a startling acoustic stimulus (SAS). The SAS triggers a postural response directly, bypassing afferent proprioceptive input. We performed two experiments. First, 18 HSP patients and nine healthy controls stood on a balance platform and were instructed to counteract forward and backward balance perturbations, without taking a step or grabbing a handrail. Second, 12 HSP patients and nine controls received backward perturbations, while a SAS accompanied onset of platform motion in 25% of trials. HSP patients were less successful than controls in maintaining balance following backward and forward perturbations. Furthermore, latencies of postural responses were significantly delayed in HSP-patients, by 34 ms in gastrocnemius following forward, and by 38 ms in tibialis anterior following backward perturbations. A SAS accelerated postural responses in all participants, but more so in HSP patients whose latencies were normalized. Our results suggest that delayed postural responses in HSP patients contribute to their balance problems. Combining balance perturbations with a SAS restored normal latencies, suggesting that conduction of efferent signals (presumably by the reticulospinal tract) is normal. We therefore suggest that the delayed postural responses in HSP are caused by slowed conduction time via the posterior spinal columns.

Does calf muscle spasticity contribute to postural imbalance? A study in persons with pure hereditary spastic paraparesis.

OBJECTIVES: The contribution of spasticity to postural imbalance in patients with upper motor neuron syndrome is still unclear. This study aimed to evaluate the responses to support-surface perturbations in patients with hereditary spastic paraparesis (HSP). These patients typically suffer from bilateral spasticity with relatively preserved muscle strength of the lower limbs. Particularly toes-up rotations were expected to be destabilizing due to insufficient suppression of calf muscle stretch reflexes. METHODS: Participants were seventeen symptomatic community-dwelling patients with autosomal dominant pure HSP and seventeen healthy controls. All patients had increased muscle tone of the triceps surae (TS) but no muscle contractures. Perturbations were applied by rotating or translating a platform with increasing intensity in four sagittal-plane directions. The primary outcome was maximum intensity ('limit of stability') sustained without stepping or grabbing in each type of perturbation. Leg muscle tone and strength were assessed with the Modified Ashworth Scale and Medical Research Council (MRC) scale, respectively. RESULTS: For toes-up perturbations, limits of stability in patients were substantially lower than in controls, which were related to TS muscle tone but not to tibialis anterior (TA) strength. Toes-down rotations were indiscriminative. For backward perturbations, patients also had lower limits of stability, unrelated to TA strength or TS muscle tone. In forward perturbations, patients with TS strength MRC 4 were less stable than patients with normal TS strength and controls. CONCLUSION: Calf muscle spasticity and weakness differently contribute to postural imbalance in patients with HSP. This notion could have implications for the clinical management of spasticity.

Short-latency stretch reflexes do not contribute to premature calf muscle activity during the stance phase of gait in spastic patients.

OBJECTIVE: To identify whether a relationship exists between stretch and activity of the calf muscles during the stance phase of gait in patients with upper motor neuron syndrome (UMNS), while taking into account the physiologic phase shift between these entities. DESIGN: Survey. SETTING: Ambulatory care and general community. PARTICIPANTS: Patients with UMNS (n=15; 9 patients with stroke, 6 patients with hereditary spastic paraparesis) with premature calf muscle activity during the stance phase of gait and healthy controls (n=13). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Timing of optimal association (phase shift) between the lengthening velocity of the gastrocnemius muscle and its electromyographic activity as revealed by cross-correlation analyses. RESULTS: Although premature calf muscle activity was evident in the patient groups, the phase shift between calf muscle stretch and its activity did not correspond with the monosynaptic stretch reflex latency (40- to 80-ms time window). However, there was a main effect of group on the phase shifts (F(3,33)=3.23, P=.035). Post hoc analysis revealed that in the paretic leg of stroke patients, the electromyographic activity preceded the lengthening velocity by 9 ± 54ms, whereas in the control group, the electromyographic activity followed the pattern of the muscle-lengthening velocity with a delay of 61 ± 54ms (P=.029). CONCLUSIONS: Short-latency stretch reflexes do not significantly contribute to premature calf muscle activity in the stance phase of (spastic) gait. This notion questions the validity of the clinical assessment of hyperreflexia and clonus of the calf as a predictor of calf muscle spasticity during gait.

Deficits underlying impaired visually triggered step adjustments in mildly affected stroke patients.

BACKGROUND: The ability to make step adjustments while walking is often impaired following a stroke, but the basic sensorimotor control deficits responsible have not been established. OBJECTIVE: To identify these deficits in Patients who have recovered from stroke leaving only mild lower limb impairment. METHODS: Ten stroke and 10 age-matched control patients stepped onto an illuminated rectangle. In 40% of trials it jumped 140 mm either medially or laterally when the stepping foot left the ground, thus provoking a mid-step adjustment. In a separate block, patients performed the same task but with the body supported by a frame to eliminate balance responses. RESULTS: Irrespective of support condition stroke patients produced short-latency foot trajectory adjustments compatible with a fast-acting, possibly subcortical, visuomotor process. However, the latency was slightly but significantly longer for the contralesional leg (148 ms) than the ipsilesional leg (141 ms) and longer than for controls (129 ms). Stroke patients' foot adjustments were executed slower and undershot the target more than controls. These deficits were most pronounced in the medial direction when the body was unsupported. The pattern of undershooting was the same for ipsilesional and contralesional legs. CONCLUSIONS: Mildly impaired stroke patients have deficits in initiating and executing visually triggered step adjustments but more profound difficulties with balance control during the adjustment, which caused them to suppress mid-step adjustments of foot placement in the medial direction where balance demands were greatest. Paradoxically, such suppression outside the laboratory may also threaten balance if it leads to unsafe foot placement or obstacle collision.

Evidence of a logarithmic relationship between motor capacity and actual performance in daily life of the paretic arm following stroke.

OBJECTIVE: To examine the associations between actual performance in daily life and function, capacity and self-perceived performance of the paretic upper limb following stroke. POPULATION: Seventeen individuals with stroke. OUTCOME MEASURES: Correlation coefficients between actual performance (measured with the Stroke-Upper Limb Activity Monitor), function (Fugl-Meyer Assessment), capacity (Action Research Arm test) and self-perceived performance (ABILHAND questionnaire). RESULTS: High correlations were found between actual performance and function (r = 0.75; 95% confidence interval (CI): 0.42-0.90), and capacity (r =0.71; 95% CI: 0.35-0.89), whereas a moderate correlation was found between actual performance and self-perceived performance (r = 0.64; 95% CI: 0.21-0.86). For the relationship between actual performance and both function and capacity, logarithmic regression explained more variance than did linear regression. CONCLUSION: The present study provides first evidence of the existence of a non-linear relationship between actual performance, function and capacity of the paretic upper limb following stroke. The results indicate that function and capacity need to reach a certain threshold-level before actual performance also starts to increase. Because of the small sample size of the present study caution is needed when generalizing these results.

Falls in individuals with stroke.

Stroke survivors are at high risk for falls in all poststroke stages. Falls may have severe consequences, both physically and psychosocially. Individuals with stroke have an increased risk for hip fractures, and after such a fracture, they less often regain independent mobility. In addition, fear of falling is a common consequence of falls, which may lead to decreased physical activity, social deprivation and, eventually, loss of independence. Important risk factors for falls are balance and gait deficits. Stroke-related balance deficits comprise reduced postural stability during quiet standing and delayed and less coordinated responses to both self-induced and external balance perturbations. Gait deficits include reduced propulsion at push-off, decreased hip and knee flexion during the swing phase, and reduced stability during the stance phase. Interventions addressing these deficits can be expected to prevent falls more successfully. Preliminary evidence shows that task-specific exercise programs targeting balance and gait deficits can indeed reduce the number of falls in individuals with stroke. Technological advances in assistive devices are another promising area. More research is needed, however, to provide conclusive evidence of the efficacy of these interventions regarding the prevention of falls in individuals with stroke.

The stroke upper-limb activity monitor: its sensitivity to measure hemiplegic upper-limb activity during daily life.

OBJECTIVE: To test the Stroke Upper-Limb Activity Monitor (Stroke-ULAM), which uses electrogoniometry and accelerometry to measure the amount of upper-limb usage in stroke patients in daily life conditions, for its sensitivity to discriminate between moderately recovered and well-recovered stroke patients and control subjects. DESIGN: Cross-sectional study. SETTING: At home or a rehabilitation center. PARTICIPANTS: Seventeen patients with stroke and 5 control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Level of usage of upper limb and the percentage of affected upper-limb activity compared with unaffected upper-limb activity (proportion). RESULTS: The level of usage of the affected upper limb of stroke patients was lower than that of the nondominant upper limb of control subjects (electrogoniometry, 97.8 degrees+/-92.3 degrees/min vs 286.2 degrees+/-46.5 degrees/min, P<.01; accelerometry 1.0+/-0.5 g/min vs 2.4+/-0.8 g/min, P<.01). Stroke patients had lower proportions than control subjects in both electrogoniometry (22.6%+/-18.0% vs 84.6%+/-9.8%, P<.01) and accelerometry (39.2%+/-21.4% vs 93.3%+/-5.0%, P<.01). Well-recovered stroke patients had significantly higher proportions compared with moderately recovered patients on both electrogoniometry and accelerometry. CONCLUSIONS: The Stroke-ULAM sensitively measures actual performance, and therefore can be a valuable addition to the mostly capacity-oriented tools currently used to evaluate upper-limb function. Proportion is preferred to the level of usage.