Search Results

You are looking at 1 - 10 of 54 items for :

  • "seasonal variation" x
Clear All
Restricted access

Maria Paula Santos, Margarida Matos and Jorge Mota

This study aimed to describe seasonal variations in Portuguese adolescents’ physical activity, in organized and nonorganized physical activities, according to gender and age group. Data from the Portuguese second wave of the Health Behaviour in School-Aged Children (HBSC) study was used. The sample comprised 6,131 public school students ages 10 to 17 years (age = 14.0 ± 1.85 years old), and 51% were girls. Physical activity was measured by questionnaire and participants were categorized as “active” or “low active” according to their reported weekly participation in physical activity sessions. Participation in organized and nonorganized physical activities of all age groups was more frequent during the spring and summer period. Results suggest that appropriate strategies should be developed to promote involvement in sports and other physical activity, particularly organized physical activity programs, among adolescents throughout the year.

Restricted access

Valerie Carson and John C. Spence

The purpose of this review was to examine seasonal variation in physical activity among children and adolescents. Searches were conducted of electronic databases for studies on seasonal differences in physical activity levels. A total of 35 studies, including children and adolescents between the ages of 2–19 years, were reviewed. Overall, 83% (29/35) of the studies found seasonal variation in physical activity among children and/or adolescents. The results were consistent regardless of the region, physical activity measure, or the study design but the findings were inconsistent across age categories.

Restricted access

Lachlan J.G. Mitchell, Ben Rattray, Paul Wu, Philo U. Saunders and David B. Pyne

analyzed to assess variation associated with different strokes and changes over time. The dataset for seasonal variation included 27 swimmers with 4 (3) observations (mean [SD]) per athlete. There were 10 breaststroke, 11 freestyle, and 6 backstroke swimmers. The data from these athletes were also analyzed

Restricted access

Elizabeth M. Broad, Louise M. Burke, Greg R. Cox, Prue Heeley and Malcolm Riley

Fluid losses (measured by body weight changes) and voluntary fluid intakes were measured in elite basketball, netball, and soccer teams during typical summer and winter exercise sessions to determine fluid requirements and the degree of fluid replacement. Each subject was weighed in minimal clothing before and immediately after training, weights, and competition sessions; fluid intake, duration of exercise, temperature and humidity, and opportunity to drink were recorded. Sweat rates were greatest during competition sessions and significantly lower during weights sessions for all sports. Seasonal variation in dehydration (%DH) was not as great as may have been expected, particularly in sports played indoors. Factors influencing fluid replacement during exercise included provision of an individual water bottle, proximity to water bottles during sessions, encouragement to drink, rules of the game, duration and number of breaks or substitutions, and awareness of personal sweat rates. Guidelines for optimizing fluid intakes in these three sports are provided.

Restricted access

Evelien Backx, Cindy van der Avoort, Michael Tieland, Kamiel Maase, Arie Kies, Luc van Loon, Lisette de Groot and Marco Mensink

Studies monitoring vitamin D status in athletes are seldom conducted for a period of 12 months or longer, thereby lacking insight into seasonal fluctuations. The objective of the current study was to identify seasonal changes in total 25-hydroxyvitamin D (25(OH)D) concentration throughout the year. Fifty-two, mainly Caucasian athletes with a sufficient 25(OH)D concentration (>75 nmol/L) in June were included in this study. Serum 25(OH)D concentration was measured every three months (June, September, December, March, June). In addition, vitamin D intake and sun exposure were assessed by questionnaires at the same time points. Highest total 25(OH)D concentrations were found at the end of summer (113 ± 26 nmol/L), whereas lowest concentrations were observed at the end of winter (78 ± 30 nmol/L). Although all athletes had a sufficient 25(OH)D concentration at the start of the study, nearly 20% of the athletes were deficient (<50 nmol/L) in late winter.

Restricted access

Johann C. Bilsborough, Thomas Kempton, Kate Greenway, Justin Cordy and Aaron J. Coutts

Purpose:

To compare development and variations in body composition of early-, mid-, and late-career professional Australian Football (AF) players over 3 successive seasons.

Methods:

Regional and total-body composition (body mass [BM], fat mass [FM], fat-free soft-tissue mass [FFSTM], and bone mineral content [BMC]) were assessed 4 times, at the same time of each season—start preseason (SP), end preseason (EP), midseason (MS), and end season (ES)—from 22 professional AF players using pencil-beam dual-energy X-ray absorptiometry. Nutritional intake for each player was evaluated concomitantly using 3-d food diaries. Players were classified according to their age at the beginning of the observational period as either early- (<21 y, n = 8), mid- (21 to 25 y, n = 9), or late- (>25 y, n = 5) career athletes.

Results:

Early-career players had lower FFSTM, BMC, and BM than mid- and late-career throughout. FM and %FM had greatest variability, particularly in the early-career players. FM reduced and FFSTM increased from SP to EP, while FM and FFSTM decreased from EP to MS. FM increased and FFSTM decreased from MS to ES, while FM and FFSTM increased during the off-season.

Conclusions:

Early-career players may benefit from greater emphasis on specific nutrition and resistance-training strategies aimed at increasing FFSTM, while all players should balance training and diet toward the end of season to minimize increases in FM.

Restricted access

Davide Ferioli, Ermanno Rampinini, Andrea Bosio, Antonio La Torre and Nicola A. Maffiuletti

available in literature on seasonal variations in the ability to sustain CODs efforts among adult male basketball players do not allow for a thorough comparison with previous studies. The main limitation of this study is that basketball players were selected from just 1 national tournament; thus, the

Restricted access

Akitomo Yasunaga, Fumiharu Togo, Eiji Watanabe, Hyuntae Park, Sungjin Park, Roy J. Shephard and Yukitoshi Aoyagi

The interactions of sex, age, season, and habitual physical activity were examined in 41 male and 54 female Japanese age 65–83 yr, using a pedometer/accelerometer that determined step counts and amounts of physical activity (<3 and >3 metabolic equivalents [METs]) throughout each 24-hr period for an entire year. All 3 measures were greater in men than in women. In women, age was negatively correlated with step count and activity <3 METs, but in men, it was correlated with step count and activity >3 METs. Irrespective of sex or age, all 3 activity variables were low in the winter, peaking in spring or autumn. In the summer, step counts matched the annual average, but durations of activity <3 and >3 METs were, respectively, longer and shorter than in other seasons. These findings have practical implications for those promoting physical activity for older adults.

Full access

Anna Goodman, James Paskins and Roger Mackett

Background:

Children in primary school are more physically active in the spring/summer. Little is known about the relative contributions of day length and weather, however, or about the underlying behavioral mediators.

Methods:

325 British children aged 8 to 11 wore accelerometers as an objective measure of physical activity, measured in terms of mean activity counts. Children simultaneously completed diaries in which we identified episodes of out-of-home play, structured sports, and active travel. Our main exposure measures were day length, temperature, rainfall, cloud cover, and wind speed.

Results:

Overall physical activity was higher on long days (≥ 14 hours daylight), but there was no difference between short (< 9.5 hours) and medium days (10.2–12.6 hours). The effect of long day length was largest between 5 PM and 8 PM, and persisted after adjusting for rainfall, cloud cover, and wind. Up to half this effect was explained by a greater duration and intensity of out-of-home play on long days; structured sports and active travel were less affected by day length.

Conclusions:

At least above a certain threshold, longer afternoon/evening daylight may have a causal role in increasing child physical activity. This strengthens the public health arguments for daylight saving measures such as those recently under consideration in Britain.

Restricted access

Rafaela Costa Martins, Felipe Fossati Reichert, Renata Moraes Bielemann and Pedro C. Hallal

Background:

To evaluate the 1-year stability of objectively measured physical activity among young adults living in South Brazil, as well as assessing the influences of temperature, humidity and precipitation on physical activity.

Methods:

A longitudinal study was conducted over 12 consecutive months (October 2012 to September 2013). Sixteen participants (8 men) used GT3X+ accelerometers 1 week per month for the entire year. Climate variables were obtained from an official climate information provider.

Results:

Physical activity was remarkably stable over the year—the proportion of the day spent in moderate-to-vigorous intensity physical activity (MVPA) was around 5% in every month. Average temperature (ρ = –0.64; P = .007), humidity (ρ = –0.68; P = .004) and rain (ρ = –0.67; P = .004) were inversely correlated to MVPA in the Summer. Rain was also inversely correlated to MVPA in the Spring (ρ = –0.54; P = .03).

Conclusions:

Objectively measured physical activity was stable over a 1-year period. Climate variables consistently influenced physical activity practice in the Summer, but not in the other seasons.