Muscle assessment in healthy teenagers

Gender Mediation in Adolescents’ Back Pain and Physical Fitness: A Cross-Sectional Study

There is a lack of studies that analyze the interaction between risk variables as predictors of back pain (BP) in adolescents. The objectives of this study were to examine the relationship between BP and several risk variables, and to analyze the effect of the mediation of gender in this association. This cross-sectional study included n = 617 adolescents (mean age: 14.10 ± 1.18 years old) who completed the BP Adolescent Survey and who performed the bench trunk curl (BTC) and Sorensen (SOR) tests. Males showed a significantly lower prevalence (OR: 0.67) and frequency (contingency coefficient: 1.73) of BP than females, less participation in leisure-time sedentary behaviors (LRSBs) per day of more than 2 h (Cramer’s V: 0.110), a higher sufficient Physical Activity (PA) (Cramer’s V: 0.323) and a higher score in the BTC test (Contingency coefficient: 0.346). A high BTC score indicated significantly lower risk of BP than mid (OR: 1.74; p = 0.025) or low (OR: 1.62; p = 0.022) BTC. The mediation analysis showed a significant indirect effect with a significant value for the Sobel test (z = 7.45 ± 0.111). When the BTC test value was included in the equations, the connection between gender and BP was no longer significant. There was a difference in the prevalence between gender in BP and LRSB and PA. BP was associated with the SOR test. The association between BP and gender was mediated by SOR results.

Isometric Strength Database for Muscle Maximal Voluntary Endurance Field Tests: Normative Data

Background

Different field tests are used to evaluate muscle capacity, in particular maximal voluntary isometric endurance. However, although there are some normative values for a few muscle endurance tests, these do not consider the weight, height, gender, or age of individuals, which are well-known factors that influence muscle performance.

Hypothesis/Purpose

The purpose of this study was to investigate the test–retest reproducibility of eight field tests and establish muscle endurance norms, in a healthy population, based on their anthropometric characteristics, which could allow the optimal evaluation of the entire muscle function in a quick manner.

Design

Case series.

Methods

This study was conducted in two phases. The first phase was to check the reproducibility inter- and intra-assessor for eight isometric muscle field tests on 20 volunteer subjects aged 40.9 ± 11.6 years old (age range, 21–58 years). The second part was to establish muscle maximal voluntary isometric endurance norms according to these tests on a total of 400 healthy participants grouped by age (50 males and females in each of the age brackets, 20–29; 30–39; 40–49; 50–59 years old, for a total of 200 males and 200 females).

Results

The intra- and inter-assessor reproducibility tests are good for all muscle measurements (the intraclass correlation coefficients varied between 0.915 and 0.996 and the coefficient of variation between 3.6 and 11.8%). The area under the receiver operating characteristic curves demonstrates a good sensibility with values greater than 0.7 for each test. Each muscle belt presents same ratio regardless of the age and gender group. The simultaneous multiple regression analyses highlight that the anthropometric characteristics of subjects influence significantly the performance of isometric tests.

Conclusion

This study has permitted establishing prediction equations in a healthy population according to their anthropometric characteristics as well as agonist/antagonist ratios for eight muscle isometric field tests after demonstrating a good reproducibility of all tests.

Iron deficiency anemia induces postural control disorders in young women

BACKGROUND

Due to menstruation and restrictive dietary practices, women are at a particular risk of iron deficiency anemia (IDA). This hematologic manifestation could impair postural control as it induces fatigue, muscle weakness, cognitive and neurological functions alteration.

AIM

This study aimed to investigate IDA effects on postural control in young women in comparison to healthy counterparts.

MATERIAL AND METHODS

Twenty-four young women with IDA and twenty-four controls participated in this study. Center of pressure (CoP) excursions, in the bipedal and semi-tandem postures on the firm and foam surfaces in the eyes opened (EO) and closed (EC), were recorded, and Romberg index was calculated to evaluate postural control. Besides physical performance, attentional capacity, fatigue, and heart and respiratory rates were assessed.

RESULTS

Young women with IDA had significantly higher CoP velocity (CoPv) values in the bipedal posture in both vision and surface conditions (EO [firm: P < 0.001 and foam: P < 0.01]; EC: P < 0.001), as well as in the semi-tandem posture (EO [firm: P < 0.01 and foam: P < 0.001]; EC: P < 0.001) compared to controls indicating that they had worse postural control than their peers. In addition, values of the respiratory rate (P < 0.001), attentional capacity (P < 0.001), physical performance (P < 0.001), fatigue (P < 0.001), and Romberg index on the foam surface in both postures (P < 0.05) were significantly higher in young women with IDA compared to controls.

CONCLUSIONS

Physical performance, fatigue, tachypnea and attentional capacity resulting from IDA may explain postural control disorder in young women.

Motor performance and back pain in children and adolescents: A systematic review

BACKGROUND AND OBJECTIVE

Motor performance during childhood and adolescence is recognized as a relevant determinant of present and future health, but its effects on back pain (BP) remain unclear. In this systematic review, we aimed to identify the association between motor performance and BP in children and adolescents.

DATABASES AND DATA TREATMENT

A literature search was performed in the MEDLINE, Scopus, Embase, SPORTDiscus and CINAHL databases. We included cross-sectional, cohort, case-control and controlled clinical trials (data from control groups). The inclusion criteria were as follows: (a) participants aged 6-19 years; (b) assessment motor performance components; (c) assessment of BP and (d) reported measures of association. The risk of bias was assessed by the Downs and Black instrument and the quality of evidence by the grading of recommendations, assessment, development and evaluation (GRADE).

RESULTS

A total of 2360 articles were identified, 25 of which were included in our systematic review. Of the 25 studies, 19 were evaluated as having a low risk of bias. GRADE indicated that 20 studies presented low or very low quality. Most of the studies evaluated flexibility (n = 16), muscle endurance (n = 18) and muscle strength (n = 9). Aerobic capacity, balance and speed were also examined in some studies (n < 5). Overall, motor performance (flexibility, muscle endurance, muscle strength, aerobic capacity, balance and speed) was not associated with BP. Most of the results were inconsistent because of the lack of studies, risk of bias and low quality of evidence. Only trunk extensor muscle endurance was associated with decreased BP with moderate quality of the supporting evidence. Prospective studies with a low risk of bias are warranted to further clarify this relationship in childhood and adolescence and findings may support more targeted and effective health promotion interventions.

SIGNIFICANCE

This systematic review shows that motor performance (flexibility, muscle endurance, muscle strength, aerobic capacity, balance and speed) was not associated with BP in children and adolescents. Most of the results were inconsistent because of the lack of studies, risk of bias and low quality of evidence. Only trunk extensor muscle endurance was associated with decreased BP with moderate quality of supporting evidence.

Does Sex Dimorphism Exist in Dysfunctional Movement Patterns during the Sensitive Period of Adolescence?

This study aimed to investigate sex difference in the functional movement in the adolescent period. Seven hundred and thirty adolescents (365 boys) aged 16-17 years participated in the study. The participants performed standardized Functional Movement Screen™ (FMS^TM) protocol and a t-test was used to examine sex differences in the total functional movement screen score, while the chi-square test was used to determine sex differences in the proportion of dysfunctional movement and movement asymmetries within the individual FMS^TM tests. Girls demonstrated higher total FMS^TM score compared to boys (12.7 ± 2.3 and 12.2 ± 2.4, respectively; p = 0.0054). Sex differences were present in several individual functional movement patterns where boys demonstrated higher prevalence of dysfunctional movement compared to girls in patterns that challenge mobility and flexibility of the body (inline lunge: 32% vs. 22%, df = 1, p = 0.0009; shoulder mobility: 47% vs. 26%, df = 1, p < 0.0001; and active straight leg raise: 31% vs. 9%, df = 1, p < 0.0001), while girls underperformed in tests that have higher demands for upper-body strength and abdominal stabilization (trunk stability push-up: 81% vs. 44%, df = 1, p < 0.0001; and rotary stability: 54% vs. 44%, df = 1, p = 0.0075). Findings of this study suggest that sex dimorphisms exist in functional movement patterns in the period of mid-adolescence. The results of this research need to be considered while using FMS^TM as a screening tool, as well as the reference standard for exercise intervention among the secondary school-aged population.

Influence of the Weight of a School Backpack on Spinal Curvature in the Sagittal Plane of Seven-Year-Old Children

The aim of the paper was to determine a correlation between the weight of a child's backpack, their body weight, and certain features of their body posture. Material and Methods. The study group consisted of 109 children, all aged seven years. The parameters of body posture were determined using the Zebris Ultrasonic System. Results. The number of children carrying a school backpack in accordance with recommendations was 44 subjects (40.37%). Statistically significant changes were found in the total length of the spine (Z = 2.223, p = 0.026) and between backpack weight and changes in the following parameters: the total length of the spine (r_s = −0.3999, p = 0.017), the length and the angle of the lumbar lordosis (r_s = −0.3352, p = 0.049), the angle of the lumbar lordosis (r_s = −0.5065, p = 0.002), and the sacral angle (r_s = −0.4279, p = 0.010). Conclusions. Wearing a backpack heavier than 10% of one's body weight can cause shallowing of the lumbar lordosis and a tendency towards a vertical position of the sacrum. Monitoring the weight of children's school backpacks and enabling them to leave books and notebooks at school would probably be beneficial in reducing the daily burden put on children's spines.

Is back pain during childhood or adolescence associated with muscle strength, muscle endurance or aerobic capacity: three systematic literature reviews with one meta-analysis

Background

Back pain is a common condition during childhood and adolescence. The causes of back pain are largely unknown but it seems plausible that some physical factors such as back muscle strength, back muscle endurance and aerobic capacity may play a role in its development, in particular in the early years.

Objectives

The objectives of this review were to investigate in childhood and adolescence 1) if muscular strength in trunk extension is associated with back pain, 2) if muscular endurance in trunk extension is associated with back pain and 3) if aerobic capacity is associated with back pain.

Design

Three systematic critical literature reviews with one meta-analysis.

Methods

Systematic searches were made in June 2014 in PubMed, Embase and SportDiscus including longitudinal, retrospective or cross-sectional studies on back pain for subjects <20 years. Articles were accepted if they were written in French or English. The review process followed the AMSTAR recommendations. The possibility of conducting a meta-analysis was assessed for each research question.

Results

Four articles were included for the first objective, four for the second and three for the last. None of the included articles found an association between back muscle strength in extension and back pain. For the second objective, a protective association between back muscle endurance in extension and back pain was found, later confirmed in a meta-analysis (OR = 0.75, 95 % CI 0.58-0.98). The association between aerobic capacity and back pain is not clear.

Conclusions

High back muscle endurance in extension appears protective of back pain in youngsters, but the roles of high back muscle strength in extension and aerobic capacity are less clear.

The association between isoinertial trunk muscle performance and low back pain in male adolescents

The literature reports inconsistent findings regarding the association between low back pain (LBP) and trunk muscle function, in both adults and children. The strength of the relationship appears to be influenced by how LBP is qualified and the means by which muscle function is measured. The aim of this study was to examine the association between isoinertial trunk muscle performance and consequential (non-trivial) low back pain (LBP) in male adolescents. Healthy male adolescents underwent anthropometric measurements, clinical evaluation, and tests of trunk range of motion (ROM), maximum isometric strength (STRENGTH) and peak movement velocity (VEL), using an isoinertial device. They provided information about their regular sporting activities, history and family history of LBP. Predictors of "relevant/consequential LBP" were examined using multivariable logistic regression. LBP status was reassessed after 2 years and the change from baseline was categorised. At baseline, 33/95 (35%) subjects reported having experienced consequential LBP. BMI, a family history of LBP, and regularly playing sport were each significantly associated with a history of consequential LBP (p < 0.05). 85/95 (89%) boys participated in the follow-up: 51 (60%) reported no LBP at either baseline or follow-up (never LBP); 5 (6%) no LBP at baseline, but LBP at follow-up (new LBP); 19 (22%) LBP at baseline, but none at follow-up; and 10 (12%) LBP at both time-points (recurrent/persistent LBP). The only distinguishing features of group membership in these small groups were: fewer sport-active in the "never LBP" group); worse trunk mobility, in the "persistent LBP" group, lower baseline sagittal ROM in the "never LBP" and "new LBP" (p < 0.05). Regular involvement in sport was a consistent predictor of LBP. Isoinertial trunk performance was not associated with LBP in adolescents.

Avaliação da flexibilidade muscular entre meninos e meninas de 7 e 8 anos

A flexibilidade muscular tem importante papel na prevenção de algumas patologias musculoesqueléticas, além de influenciar a postura. A criança em desenvolvimento apresenta maior flexibilidade. O objetivo deste foi avaliar a flexibilidade de crianças de 7 e 8 anos e a existência de diferença entre sexo e idade para essa variável. Foram avaliadas 230 crianças das escolas municipais da cidade de Amparo, SP. A amostra constituiu-se de 130 meninas e 100 meninos saudáveis, com índice de massa corporal menor que o 85º percentil, que não praticavam esporte institucionalizado ou exercício físico em freqüência maior que duas vezes e/ou 3 horas por semana. A flexibilidade foi medida pelo teste da distância do 3º dedo ao solo. Os dados foram tratados estatisticamente para verificar a existência de diferenças de sexo e idade, adotando-se o nível de significância de 5%. Foi encontrada diferença significante de sexo (p=0,05), tendo as meninas apresentado maior distância (29,15±8,80 cm) 3º dedo-solo que os meninos (27,41±10,01 cm). Não houve diferenças entre as idades (p=0,725). As meninas apresentaram menor flexibilidade que os meninos.