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Craig Lodis, Sandra T. Sigmon, Amber Martinson, Julia Craner, Morgan McGillicuddy, and Bruce Hale

This study investigated seasonality in male and female college athletes and nonathletes. Given the literature on activity level and its positive impact on mood, it was predicted that athletes would benefit more than nonathletes with regards to seasonal symptoms. Participants completed measures of seasonality, depression, and cognitive processes during a winter month. Multiple measures of seasonality were administered to distinguish seasonal depression symptoms from nonseasonal symptoms. Results indicated that nonathletes reported more seasonal symptoms, seasonal attitudes, and rumination, gained more weight, socialized the least, and slept more than athletes. Female nonathletes reported the most impact from the changing seasons and more negative thoughts about the changing seasons. These results indicate that engaging in collegiate athletics may serve as a protective factor in seasonal depression.

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Stacy A. Clemes, Sarah L. Hamilton, and Paula L. Griffiths

Background:

This study investigated whether pedometer-determined activity varies between summer and winter in normal-weight and overweight adults.

Methods:

Forty-five normal-weight (58% female, age = 39.1 ± 12.4 years, BMI = 22.2 ± 2.1 kg/m2) and 51 overweight (49% female, age = 42.1 ± 12.5 years, BMI = 29.3 ± 4.5 kg/m2) participants completed a within-subject biseasonal pedometer study. All participants completed 2 4-week monitoring periods; 1 period in the summer and 1 period the following winter. Changes in step counts across seasons were calculated and compared for the 2 BMI groups.

Results:

Both BMI groups reported significant summer to winter reductions in step counts, with the magnitude of change being significantly greater in the normal-weight group (−1737 ± 2201 versus −781 ± 1673 steps/day, P = .02). Winter step counts did not differ significantly between the 2 groups (9250 ± 2845 versus 8974 ± 2709 steps/day, P = .63), whereas the normal-weight group reported a significantly higher mean daily step count in the summer (10986 ± 2858 versus 9755 ± 2874 steps/day, P = .04).

Conclusion:

Both normal-weight and overweight individuals experienced a reduction in step counts between summer and winter; however, normal-weight individuals appear more susceptible to winter decreases in ambulatory activity, with the greatest seasonal change occurring on Sundays. Effective physical activity policies should be seasonally tailored to provide opportunities to encourage individuals to be more active during the winter, particularly on weekends.

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Abigail Fisher, John J. Reilly, Colette Montgomery, Louise A. Kelly, Avril Williamson, Diane M. Jackson, James Y. Paton, and Stanley Grant

This study examined whether there was a significant seasonal variation in objectively measured habitual physical activity and sedentary behavior in young children. Participants were children who attend nursery in Glasgow, Scotland, and measurements were taken using uniaxial accelerometry over 3 to 6 days. There were small but significant seasonal associations with physical activity and sedentary behavior (ANOVA: p < .001 in both cases). Total physical activity (accelerometry cpm) was significantly lower in spring than in summer, fall, and winter. We also found slight but significant seasonal variations in time spent in low-intensity activity and in moderate-to-vigorous-intensity activity. Sedentary time was significantly lower in summer vs. spring and in fall vs. spring. The present study suggests that seasonality plays only a limited role in physical activity and sedentary behavior in young children in our setting. Single measures of these variables should be adequate for research purposes in the absence of marked seasonal variability. In our sample and setting, the limited degree of seasonality precluded identification of major seasonal barriers to and opportunities for physical activity.

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Bo Shen, Gwen Alexander, Sharon Milberger, and Kai-Lin C. Jen

Background:

While there is an emerging body of literature showing variations in physical activity between seasons, further investigation is needed to better understand this association in preschool-age children. This study was designed to examine seasonal variation from fall to winter in physical activity among preschoolers.

Methods:

Forty-six preschool children from 2 preschools in a large Midwestern Metropolitan area completed weekly habitual physical activity measures in both fall and following winter. The habitual physical activity was quantified with the GT1M Actigraph uniaxial accelerometer. To determine seasonal differences in physical activity, a series of paired sample t tests were conducted.

Results:

Although overall physical activity level declined in winter, the magnitude of seasonality effects seem varied in terms of contexts. Compared with the decline during after-school time and during weekends, the differences in physical activity across the 2 seasons were much less evident during the time attending preschool and during weekdays.

Conclusion:

Seasonality in physical activity can be moderated by other contextual factors, such as preschool policies and curriculum. Preschools may serve as a major battlefield for fighting against physical inactivity and obesity during childhood due to their practical controllability.

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Markus J. Klusemann, David B. Pyne, Will G. Hopkins, and Eric J. Drinkwater

Competition-specific conditioning for tournament basketball games is challenging, as the demands of tournament formats are not well characterized.

Purpose:

To compare the physical, physiological, and tactical demands of seasonal and tournament basketball competition and determine the pattern of changes within an international tournament.

Methods:

Eight elite junior male basketball players (age 17.8 ± 0.2 y, height 1.93 ± 0.07 m, mass 85 ± 3 kg; mean ± SD) were monitored in 6 seasonal games played over 4 mo in an Australian second-division national league and in 7 games of an international under-18 tournament played over 8 days. Movement patterns and tactical elements were coded from video and heart rates recorded by telemetry.

Results:

The frequency of running, sprinting, and shuffling movements in seasonal games was higher than in tournament games by 8–15% (99% confidence limits ± ~8%). Within the tournament, jogging and low- to medium-intensity shuffling decreased by 15–20% (± ~14%) over the 7 games, while running, sprinting, and high-intensity shuffling increased 11–81% (± ~25%). There were unclear differences in mean and peak heart rates. The total number of possessions was higher in seasonal than in tournament games by 8% (± 10%).

Conclusions:

Coaches should consider a stronger emphasis on strength and power training in their conditioning programs to account for the higher activity of seasonal games. For tournament competition, strategies that build a sufficient aerobic capacity and neuromuscular resilience to maintain high-intensity movements need to be employed. A focus on half-court tactics accounts for the lower number of possessions in tournaments.

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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.

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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.

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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.

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Minsoo Kang, David R. Bassett, Tiago V. Barreira, Catrine Tudor-Locke, and Barbara E. Ainsworth

Background:

The seasonal and monthly variability of pedometer-determined physical activity and its effects on accurate measurement have not been examined. The purpose of the study was to reduce measurement error in step-count data by controlling a) the length of the measurement period and b) the season or month of the year in which sampling was conducted.

Methods:

Twenty-three middle-aged adults were instructed to wear a Yamax SW-200 pedometer over 365 consecutive days. The step-count measurement periods of various lengths (eg, 2, 3, 4, 5, 6, 7 days, etc.) were randomly selected 10 times for each season and month. To determine accurate estimates of yearly step-count measurement, mean absolute percentage error (MAPE) and bias were calculated. The year-round average was considered as a criterion measure. A smaller MAPE and bias represent a better estimate.

Results:

Differences in MAPE and bias among seasons were trivial; however, they varied among different months. The months in which seasonal changes occur presented the highest MAPE and bias.

Conclusions:

Targeting the data collection during certain months (eg, May) may reduce pedometer measurement error and provide more accurate estimates of year-round averages.

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Pavle Mikulic

Purpose:

To examine variations in physical, physiological, and performance parameters over an annual training cycle in a world champion rowing crew.

Methods:

Four world-class rowers, all of them members of the men’s heavyweight quadruple sculls squad who are current world rowing champions, were assessed 3 times at regular 4-mo intervals during the 2011 season (November 2010, March 2011, and July 2011). Physical assessments included stature, body mass, body composition, whereas physiological and performance assessments obtained during an incremental rowing ergometer test to exhaustion included maximum oxygen uptake and anaerobic gas-exchange threshold with corresponding power output values.

Results:

Body mass (∼95 kg) and body composition (∼12% body fat) remained stable over the annual training cycle. Power output at anaerobic gas-exchange threshold increased +16% from November to July, whereas the corresponding oxygen uptake, expressed as a percentage of maximum oxygen uptake, increased from 83% to 90%. Maximum oxygen uptake decreased from 6.68 L/min in November to 6.10 L/min in March before rising to 6.51 L/min in July. The corresponding power output increased steadily from 450 W to 481 W.

Conclusion:

Seasonal variation in body mass and body composition of 4 examined world-class rowers was minimal. Oxygen uptake and power output corresponding to anaerobic threshold continuously increased from off-season to peak competition season. Seasonal variation in maximum oxygen uptake reached ∼10%; however, it remained above 6 L/min, that is, the value consistently observed in top caliber heavyweight rowers regardless of the time of the assessment.