60 research outputs found
Effects of Dairy Consumption on Body Composition and Bone Properties in Youth: A Systematic Review
Background: According to previous reviews, there is no clear evidence on the effects of dairy
consumption on body composition and bone properties in pediatric populations. There is a need
for further assessment of existing findings and the methodologic quality of studies before
summarizing the evidence.
Objective: The aim of the study was to assess the quality, methodologies, and substantive
findings of randomized controlled trials (RCTs) that examined the effects of dairy consumption
on body size, body composition, and bone properties in children and adolescents.
Methods: After searching PubMed and Google Scholar up to December 2016, 15 RCTs were
retained and included in this systematic review for further analysis. The quality of the included
studies was assessed via the Jadad scale; detailed methodologic and statistical characteristics
were evaluated, and the main findings were summarized.
Results: The effects of dairy consumption were found to be significant for bone structure and
nonsignificant for body size and composition. Eight of the 11 RCTs that assessed bone found
significant effects (P , 0.05) for bone mineral content and bone mineral density (BMD), with an
average 8% increase in BMD after 16 mo of dairy consumption. Conversely, significant effects
(P , 0.05) were found only in 2 of the 14 RCTs that focused on body size (i.e., height and weight)
and in only 1 of the 11 RCTs that focused on body composition (i.e., lean mass).
Conclusions: The systematic consumption of dairy products may benefit bone structure and
development, but it does not appear to affect body composition or body size in children and
adolescents. On the basis of the Jadad scale, the methodologic quality of the 15 RCTs was rated
as good overall. However, there were methodologic disparities and limitations that may have led
to nonsignificant results, particularly for body size and composition. Future RCTs designed to
address these limitations are warranted.Brock University Library Open Access Publishing Fun
Canadian Society for Exercise Physiology Position Paper: Resistance Training in Children and Adolescents
Many position stands and review papers have refuted the myths associated with
resistance training (RT) in children and adolescents. With proper training methods, RT
for children and adolescents can be relatively safe and improve overall health. The
objective of this position paper and review is to highlight research and provide
recommendations in aspects of RT that have not been extensively reported in the
pediatric literature. In addition to the well-documented increases in muscular strength and
endurance, RT has been used to improve function in pediatric patients with cystic
fibrosis, cerebral palsy and burn victims. Increases in children’s muscular strength have
been attributed primarily to neurological adaptations due to the disproportionately higher
increase in muscle strength than in muscle size. Although most studies using
anthropometric measures have not shown significant muscle hypertrophy in children,
more sensitive measures such as magnetic resonance imaging and ultrasound have
suggested hypertrophy may occur. There is no minimum age for RT for children.
However the training and instruction must be appropriate for children and adolescents
involving a proper warm-up, cool-down and an appropriate choice of exercises. It is
recommended that low-to-moderate intensity resistance should be utilized 2-3 times per
week on non-consecutive days, with 1-2 sets initially, progressing to 4 sets of 8-15
repetitions for 8-12 exercises. These exercises can include more advanced movements
such as Olympic style lifting, plyometrics and balance training, which can enhance
strength, power, co-ordination and balance. However specific guidelines for these more
advanced techniques need to be established for youth. In conclusion, a RT program that is
within a child’s or adolescent’s capacity, involves gradual progression under qualified instruction and supervision with appropriately sized equipment can involve more
advanced or intense RT exercises which can lead to functional (i.e. muscular strength,
endurance, power, balance and co-ordination) and health benefits
Role of the Myokine Irisin on Bone Homeostasis: Review of the Current Evidence
Bone is a highly dynamic tissue that is constantly adapting to micro-changes to facilitate movement. When the balance between bone building and resorption shifts more towards bone resorption, the result is reduced bone density and mineralization, as seen in osteoporosis or osteopenia. Current treatment strategies aimed to improve bone homeostasis and turnover are lacking in efficacy,
resulting in the search for new preventative and nutraceutical treatment options. The myokine irisin, since its discovery in 2012, has been shown to play an important role in many tissues including muscle, adipose, and bone. Evidence indicate that irisin is associated with increased bone formation and decreased bone resorption, leading to reduced risk of osteoporosis in post-menopausal women. In addition, low serum irisin levels have been found in individuals with osteoporosis and osteopenia. Irisin targets key signaling proteins, promoting osteoblastogenesis and reducing osteoclastogenesis. The present review summarizes the existing evidence regarding the effects of irisin on bone homeostasis.Brock Library Open Access Publishing Fun
Does bracing affect bone health in women with adolescent idiopathic scoliosis?
Purpose: Adolescent idiopathic scoliosis (AIS) is often associated with low bone mineral content and density (BMC,
BMD). Bracing, used to manage spine curvature, may interfere with the growth-related BMC accrual, resulting in
reduced bone strength into adulthood. The purpose of this study was to assess the effects of brace treatment on
BMC in adult women, diagnosed with AIS and braced in early adolescence.
Methods: Participants included women with AIS who: (i) underwent brace treatment (AIS-B, n = 15, 25.6 ± 5.8 yrs),
(ii) underwent no treatment (AIS, n = 15, 24.0 ± 4.0 yrs), and (iii) a healthy comparison group (CON, n = 19, 23.5 ±
3.8 yrs). BMC and body composition were assessed using dual-energy X-ray absorptiometry. Differences between
groups were examined using a oneway ANOVA or ANCOVA, as appropriate.
Results: AIS-B underwent brace treatment 27.9 ± 21.6 months, for 18.0 ± 5.4 h/d. Femoral neck BMC was lower
(p = 0.06) in AIS-B (4.54 ± 0.10 g) compared with AIS (4.89 ± 0.61 g) and CON (5.07 ± 0.58 g). Controlling for lean
body mass, calcium and vitamin D daily intake, and strenuous physical activity, femoral neck BMC was statistically
different (p = 0.02) between groups. A similar pattern was observed at other lower extremity sites (p < 0.05), but not
in the spine or upper extremities. BMC and BMD did not correlate with duration of brace treatment, duration of
daily brace wear, or overall physical activity.
Conclusion: Young women with AIS, especially those who were treated with a brace, have significantly lower BMC
in their lower limbs compared to women without AIS. However, the lack of a relationship between brace treatment
duration during adolescence and BMC during young adulthood, suggests that the brace treatment is not the likely
mechanism of the low BMC
Comparison of different wheelchair seating on thermoregulation and perceptual responses in thermoneutral and hot conditions in children
We examined the effects of 4 different wheelchair seatings on physiological and perceptual measures in 21 healthy, pre-pubertal children (9 ± 2 years). Participants were able-bodied and did not regularly use a wheelchair. Participants sat for 2 h in Neutral (∼22.5 °C, ∼40%RH) and Hot (∼35 °C, ∼37%RH) conditions. Four seating technologies were: standard incontinent cover and cushion (SEAT1); standard incontinent cover with new cushion (SEAT2) were tested in Neutral and Hot; new non-incontinent cover with new cushion (SEAT3); new incontinent cover and new cushion (SEAT4) were tested in Neutral only. Measurements included skin blood flow (SkBF), sweating rate (SR) and leg skin temperature (TlegB) on the bottom of the leg (i.e. skin-seat interface), heart rate (HR), mean skin temperature, tympanic temperature, thermal comfort, and thermal sensation. During Neutral, SkBF and TlegB were lower (∼50% and ∼1 °C, respectively) and SR higher (∼0.5 mg cm−2·min−1) (p  0.05). During Hot, HR and temperatures were higher than in Neutral but there were no differences (p > 0.05) between SEATs. New cover and cushion improved thermoregulatory responses during Neutral but not Hot. An impermeable incontinent cover negated improvements from cushion design. Seat cover appears more important than seat cushion during typical room conditions
Do Neuro-Muscular Adaptations Occur in Endurance-Trained Boys and Men?
Most research on the effects of endurance training has focused on endurance training's health-related benefits and metabolic effects in both children and adults. The purpose of this study was to examine the neuromuscular effects of endurance training and to investigate whether they differ in children (9.0-12.9 years) and adults (18.4-35.6 years). Maximal isometric torque, rate of torque development (RTD), rate of muscle activation (Q30), electromechanical delay (EMD), and time to peak torque and peak RTD were determined by isokinetic dynamometry and surface electromyography (EMG) in elbow and knee flexion and extension. The subjects were 12 endurance-trained and 16 untrained boys, and 15 endurance-trained and 20 untrained men. The adults displayed consistently higher peak torque, RTD, and Q30, in both absolute and normalized values, whereas the boys had longer EMD (64.7+/-17.1 vs. 56.6+/-15.4 ms) and time to peak RTD (98.5+/-32.1 vs. 80.4+/-15.0 ms for boys and men, respectively). Q30, normalized for peak EMG amplitude, was the only observed training effect (1.95+/-1.16 vs. 1.10+/-0.67 ms for trained and untrained men, respectively). This effect could not be shown in the boys. The findings show normalized muscle strength and rate of activation to be lower in children compared with adults, regardless of training status. Because the observed higher Q30 values were not matched by corresponding higher performance measures in the trained men, the functional and discriminatory significance of Q30 remains unclear. Endurance training does not appear to affect muscle strength or rate of force development in either men or boys
Daily calcium intake in male children and adolescents obtained from the rapid assessment method and the 24-hour recall method
<p>Abstract</p> <p>Background</p> <p>In order to rapidly assess nutrient intake, Food Frequency Questionnaires (FFQ) have been developed and proven to be reliable for quick, user friendly analysis in adults. However, the accuracy of these questionnaires in children has been studied to a limited extent. The aim of this study was to compare the daily calcium intake values obtained from the Rapid Assessment Method (RAM), an FFQ, for assessing daily calcium intake in child and adolescent males with the values obtained from the 24-hour recall method.</p> <p>Methods</p> <p>Subjects included 162 child and adolescent males, aged 9–16 years, subdivided into elementary school (ES, 9–12 years) and high school (HS, 14–16 years) age groups.</p> <p>Results</p> <p>Daily calcium intake was significantly lower in ES compared with HS, using both methods. The intra-class correlation coefficients (ICC) between RAM values and those obtained using the 24-hour recall questionnaire were significant yet moderate (ICC = 0.46 and 0.43 for ES and HS, respectively). However, daily calcium intake obtained using RAM was significantly higher when compared with the 24-hour recall values in both ES (1576 +/- 1101 vs. 1003 +/- 543 mg, in RAM and 24-hour, respectively) and in HS males (1873 +/- 739 vs. 1159 +/- 515 mg, in RAM and 24-hour, respectively).</p> <p>Conclusion</p> <p>RAM overestimates daily calcium intake as compared with the 24-hour recall method in both child and adolescent males.</p
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