Effectiveness of Swimming Program in Adolescents with Down Syndrome

The aim of this study was to estimate the influence of a 33-week swimming program on aerobic capacity, muscle strength, balance, flexibility, and body composition of adolescents with Down syndrome (DS). Twenty-two adolescents diagnosed with DS were randomly allocated into the training group (T) and the control group (C). The T group participated in 33 weeks of water-based exercise and a swimming program while the control group maintained their normal daily activity. Following thirty-three weeks of swimming program, body mass, body fat, and BMI of the T group decreased significantly (from 56.8 ± 7.97 kg to 55.0 ± 7.11 kg, from 15.1 ± 4.47 kg to 13.2 ± 3.92 kg, and from 25.1 ± 2.37 to 24.0 ± 2.05, respectively) while a significant increase was recorded in C (from 57.3 ± 8.43 kg to 59.7 ± 8.29 kg, from 14.5 ± 2.76 kg to 16.0 ± 3.11 kg, and from 25.4 ± 2.46 to 26.0 ± 2.72, respectively). Moreover, significant improvement in aerobic capacity in the T group was noted; VO2max (mL/kg/min) increased by 16.3% in T and decreased by 4.8% in C. Improvement in static arm strength, trunk strength and endurance/functional strength were noted in T, while the parameters did not change in C. The speed of arm movement, balance and flexibility did not change following the intervention. Also, the aquatic skills improved significantly in the training group. Changes in C were not significant. The results of our study indicate that 33-week swimming program significantly improved health status and swimming skills in adolescents with DS.

Dolor de espalda en adolescentes: factores asociados desde un enfoque multifactorial (Back pain in adolescents: associated factors with a multifactorial approach)

El objetivo de la presente investigación fue analizar la prevalencia del dolor de espalda en adolescentes y hallar la relación entre el dolor de espalda y algunos factores asociados. La muestra estuvo constituida por 57 escolares con una edad media de 14,11±0,43 años. Se tomaron los datos relativos al peso y la talla, con los que se calculó el IMC; se administró la encuesta sobre el dolor de espalda en adolescentes para conocer los hábitos sobre práctica deportiva, sedentarismo, forma de llevar la mochila y dolor de espalda; y se midió la fuerza flexora y extensora del tronco y la flexibilidad de la musculatura isquiosural. Se encontró que el 43,86% de los sujetos habían sufrido dolor de espalda en algún momento de sus vidas, siendo el dolor lumbar el más habitual (36,84%). Entre un 15 y 25% aproximadamente de los adolescentes habían visitado al médico de cabecera o al fisioterapeuta a causa del dolor de espalda a lo largo de su vida. Se encontró cierta tendencia, sin que hubiera diferencias significativas, a que la presencia de dolor de espalda fuera mayor entre los practicantes de deporte (r=0,250; p=0,059), especialmente entre los que practicaban menos horas a la semana (r=0,348; p=0,076). Los escolares que presentaron dolor de espalda tenían tendencia a presentar menos fuerza flexora y extensora del tronco y una menor extensibilidad de la musculatura isquiosural, sin que hubiera diferencias significativas entre grupos (p>0,05). El sexo, el tiempo en actividades sedentarias, la forma de llevar la mochila y el IMC tampoco se relacionaron con el dolor de espalda (p>0,05). En conclusión, la práctica de deporte, la fuerza del tronco y la extensibilidad isquiosural son variables que podrían afectar a la incidencia de dolor de espalda en adolescentes. Abstract. The objective of the current study was to analyze the prevalence of spine pain in adolescents and to show the relationship between back pain and some associated factors. The sample consisted of 57 schoolchildren, mean age 14.11±0.43 years-old. Body mass and height were measured to calculate BMI; the survey about back pain in adolescents was completed to register the prevalence of PA, sedentary lifestyle, way of carrying a backpack and spine pain; and the strength of the flexor and extensor muscles and hamstring extensibility was evaluated. It was found that a 43.86% of the subjects had spine pain, with low back pain as the most common (36.84%). Approximately 15 to 25% of the adolescents had visited the family doctor or physiotherapist because of spine pain throughout their lives. A tendency, with no significant differences, was found for a greater presence of spine pain in sport practitioners (r=0.250; p=0.059), especially among those who practiced fewer hours a week (r=0.348; p=0.076). The schoolchildren who presented spine pain tended to have less flexor and extensor strength of the trunk and less hamstring extensibility, with no significant differences between groups (p>0.05). Sex, time spent in sedentary activities, way of carrying a backpack and BMI were not related to spine pain (p>0.05). In conclusion, the sport practice, trunk strength and hamstring extensibility are variables that could affect the incidence of spine pain in adolescents.

Factorial Structure of Trunk Motor Qualities and Their Association with Explosive Movement Performance in Young Footballers

This study examined the factorial structure of trunk motor qualities and their associations with explosive muscular performance of football players. Ninety-one young male football players (age: 15–21 years; body height: 1.78 ± 0.07 m; body mass: 70.3 ± 7.5 kg) performed a series of tests: four standing and four seated isometric trunk strength tests, seven trunk power (medicine ball throwing) tests, four trunk endurance tests and four explosive movement performance tests. A principal component factor analysis (PCA) was used to determine the structure of trunk motor qualities, and correlational analyses were used to assess linear associations between trunk motor qualities and explosive performance. The PCA revealed four independent factors—trunk power, standing and seated isometric trunk strength, and trunk muscle endurance. Only trunk power had significant moderate, logically positive associations with sprint and vertical jump performance (common variance: 25–36%), while other associations between trunk motor factors and explosive movement performance were generally low to very low. These results indicate that trunk muscle functions of football players can be described with three independent motor qualities—trunk power, trunk strength and trunk muscle endurance, with only trunk power being moderately associated with players’ sprinting and jumping performance.

Similar Pain Intensity Reductions and Trunk Strength Improvements Following Whole-Body Electromyostimulation vs. Whole-Body Vibration vs. Conventional Back-Strengthening Training in Chronic Non-specific Low Back Pain Patients: A Three-Armed Randomized Controlled Trial

The aim of this multicenter trial was to compare the effects of whole-body electromyostimulation (WB-EMS) and whole-body vibration (WBV) with conventional back-strengthening training (CT) on changes in mean back pain intensity (MPI) and trunk strength in patients suffering from chronic non-specific low back pain (CNLBP). Two-hundred and forty CNLBP patients (40–70 years; 62% female) were randomly assigned to three intervention arms (WB-EMS: n = 80 vs. WBV: n = 80 vs. CT: n = 80). All training intervention programs were performed for 12 weeks in their usual commercial training setting. Before and during the last 4 weeks of the intervention, MPI was recorded using a 4-week pain diary. Additionally, maximal isometric trunk extension and -flexion strength was assessed on the BackCheck® machine. A moderate but significant decrease of MPI was observed in all groups (WB-EMS: 29.7 ± 39.1% (SMD 0.50) vs. WBV: 30.3 ± 39.3% (SMD 0.57) vs. CT: 30.5 ± 39.6% (SMD 0.59); p < 0.001). Similar findings were observed for maximal isometric strength parameters with a significant increase in all groups (extension: WB-EMS: 17.1 ± 25.5% vs. WBV: 16.2 ± 23.6% vs. CT: 21.6 ± 27.5%; p < 0.001; flexion: WB-EMS: 13.3 ± 25.6% vs. WBV: 13.9 ± 24.0% vs. CT: 13.9 ± 25.4%; p < 0.001). No significant interaction effects for MPI (p = 0.920) and strength parameters (extension: p = 0.436; flexion: p = 0.937) were observed. WB-EMS, WBV, and CT are comparably effective in improving MPI and trunk strength. However, training volume of WB-EMS was 43 or 62% lower, compared with CT and WBV.

Evaluating objective measures of impairment to trunk strength and control for cross-country sit skiing

In Paralympic cross-country sit skiing, athlete classification is performed by an expert panel, so it may be affected by subjectivity. An evidence-based classification is required, in which objective measures of impairment must be identified. The purposes of this study were: (i) to evaluate the reliability of 5 trunk strength measures and 18 trunk control measures developed for the purposes of classification; (ii) to rank the objective measures, according to the largest effects on performance. Using a new testing device, 14 elite sit-skiers performed two upright seated press tests and one simulated poling test to evaluate trunk strength. They were also subjected to unpredictable balance perturbations to measure trunk control. Tests were repeated on two separate days and test–retest reliability of trunk strength and trunk control measures was evaluated. A cluster analysis was run and correlation was evaluated, including all strength and control measures, to identify the measures that contributed most to clustering participants. Intraclass correlations coefficients (ICC) were 0.71 < ICC < 0.98 and 0.83 < ICC < 0.99 for upright seated press and perturbations, respectively. Cluster analysis identified three clusters with relevance for strength and balance control measures. For strength, in upright seated press peak anterior pushing force without backrest (effect size = 0.77) and ratio of peak anterior pushing force without and with backrest (effect size = 0.72) were significant. For balance control measures, trunk range of motion in forward (effect size = 0.81) and backward (effect size = 0.75) perturbations also contributed. High correlations (− 0.76 < r < − 0.53) were found between strength and control measures. The new testing device, protocol, and the cluster analysis show promising results in assessing impairment of trunk strength and control to empower an evidence-based classification.

Isokinetic Trunk Strength in Acute Low Back Pain Patients Compared to Healthy Subjects: A Systematic Review

Background: The purpose of this systematic review was to: (I) determine the quality of evidence from studies assessing trunk isokinetic strength in subjects with acute low back pain (ALBP) compared to healthy subjects and (II) establish reference values of isokinetic trunk strength in subjects with ALBP. Methodology: Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed using keywords associated with trunk, strength and low back pain. Four databases were used: PubMed, Web of Science, Scopus and SPORTDiscus. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). Results: A total of 1604 articles were retrieved, four included in this review. All were evaluated as high risk of bias (Rob). Due to the high Rob and the diversity of protocols, instruments and variables used, it was not possible to determine reference values for subjects with ALBP, we can only establish a range of flexion peak torque (PT) between 175.1 and 89.7 Nm at 60°/s and between 185 and 81.5 Nm at 120°/s, and for extension PT between 240.0 and 91.5 Nm at 60°/s and between 217.5 and 69.2 Nm at 120°/s in subjects with ALBP. Conclusions: Due to the low quality of the evidence and the diversity of protocols used when measuring trunk isokinetic strength, it is necessary to carry out new high-quality research to establish reference values of trunk strength in subjects with ALBP.

Test–retest reliability and known-groups validity of trunk muscle tests in people with multiple sclerosis: a cross-sectional, case–control study

Objective Research on muscle performance testing reliability in people with multiple sclerosis (PwMS) has focused on limb performance while less is known about trunk strength and endurance. The objective is to 1) establish test–retest reliability of Trunk Flexion, Lateral Flexion and Extension strength tests, and Plank, Side-Bridge and Biering-Sorensen endurance tests in PwMS and matched healthy controls (HC); 2) analyze known-groups validity of these tests in PwMS and HC; 3) to compare groups for side-to-side differences; 4) to describe the relationships between trunk performance and functional mobility tests. Methods Fifteen PwMS (median EDSS = 3) and 15 HC underwent two trunk isometric strength and endurance testing sessions. Mobility was evaluated by Timed Up-and-Go (TUG) test. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Between-group differences in trunk performance were tested using the Student’s t-test for independent measures. Between-group differences in an asymmetry index were analyzed by independent t-test. Bivariate correlations between trunk tests and mobility were also examined. Results All trunk tests showed good-to-excellent relative reliability in both groups (ICC &gt; 0.71). Regarding absolute reliability, strength tests were associated with low intersession variability in both groups (MDC: MS, 11.23–36.45%; HC, 26.60–31.98%). Conversely, endurance tests showed higher variability scores in PwMS (MDC: MS, 69.55–116.50%; HC, 29.57–54.40%). PwMS displayed significantly lower trunk performance. Likewise, the asymmetry index showed significantly higher scores in PwMS for endurance assessment but not in strength tests. Significant correlations were detected in PwMS between TUG and several trunk tests (r = 0.63–0.70). Conclusions SEM and MDC scores revealed similar consistency and variability between groups for strength tests, while higher variability was observed for endurance tests in PwMS. Trunk strength tests are reliable and present discriminant validity to distinguish mildly-disabled PwMS from HC. Conversely, the high measurement error and variability of the endurance tests may hinder their application in intervention programs. Impact Determining the reliability and validity of the tests currently used to assess trunk function is of utter importance for PwMS (who not only show impaired trunk function but also wide fluctuations in performance) as it requires consistent and accurate measurements that are sensitive enough to detect minimal changes induced by rehabilitation.

What Would a Tree Say About Its Size?

When developing theories, designing studies, and interpreting the results, researchers are influenced by their perception of tree size. For example, we may compare two trees of the same size belonging to different species, and attribute any differences to dissimilarities between the species. However, the meaning of “same size” depends on the measures of size used. Wood density influences certain measures, such as biomass, but does not influence e.g., trunk diameter. Therefore, the choice of the measure of size can reverse any conclusions. Hence, it is import to consider which measure of size should be used. I argue that the most common measure of size, i.e., trunk diameter, is often a bad choice when wood density varies, as diameter is then not directly related to processes important in evolution. When trees with equal diameters but differing wood densities are compared, the tree with denser wood is larger if the measure of size is related to construction cost or trunk strength, a proxy of leaf area. From this perspective, the comparison is then conducted between a biologically larger heavy-wooded tree and a smaller light-wooded tree, and the differences between the trees may be caused by size instead of wood density. Therefore, trunk biomass and strength may often be more suitable measures of size, as they reflect the construction cost and biomechanical potency linked to leaf area crown height, often too challenging to estimate more directly. To assess how commonly inadequate measures of tree size have been used, I reviewed 10 highly cited journal articles. None of these 10 articles discussed the impact of wood density on biological size, and instead based the analyses on diameters or basal areas. This led to conclusions that could change or even reverse in an analysis based on biomass or strength. Overall, I do not suggest avoiding the use of diameter, but I recommend considering result sensitivity to the measure of size, particularly in studies ones with variable wood densities.

Isometric Trunk Strength Assessment of Athletes: Effects of Sex, Sport, and Low Back Pain History

Context: The importance of isometric trunk strength (ITS) among sport science professionals is higher than its actual reported effect size on either performance or low back pain (LBP) occurrence. Objective: To provide normative values of ITS and strength ratios, and to evaluate the effect of sex, sports discipline, and LBP status. Design: Crossover study. Setting: University research laboratory. Participants: Five hundred and sixty-seven elite athletes (186 females) with and without a history of LBP from different sports. Main Outcome Measure: Participants underwent ITS testing for trunk flexors, extensors, and lateral flexors. Normalized maximal strength (in newton meter per kilogram) and strength ratios were calculated. Differences between sex, LBP, and sport disciplines were assessed with 3-way analysis of variance (sex × LBP status × 7 sport categories) and partial eta-squared () effect size. The predictive validity of ITS for LBP was checked with receiver operating characteristics (area under the curve). Results: The authors found significant differences in extensor and flexor ITS in favor of male athletes (medium , P < .05), while sex differences in lateral flexion ITS had a low size effect (P < .05). A low size effect was also observed for the differences in strength ratios extensors/flexors (mean 1.47; 95% confidence interval, 1.45–1.50) and left flexors/right flexors (mean 0.99; 95% confidence interval, 0.98–1.01) among sexes. The sport discipline-related differences generally had a low size effect. No significant differences in ITS were found between LBP and LBP-free athletes. Only 50% to 58% of athletes (area under the curve, 0.501–0.582) were correctly classified as LBP or LBP-free using different ITS and strength ratio variables. Conclusions: ITS and strength ratios have low predictive validity for LBP history but may discriminate between sex and sport disciplines. Our data are a useful reference point for meaningful individual results interpretation when athletes are evaluated during training or rehabilitation.