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Anna E. Greer, Xuemei Sui, Andréa L. Maslow, Beau Kjerulf Greer and Steven N. Blair

Background:

To date, no longitudinal studies have examined the influence of sedentary behavior on metabolic syndrome development while accounting for cardiorespiratory fitness.

Purpose and Methods:

This prospective study examined the relationship between sedentary behavior and incident metabolic syndrome while considering the effects of physical activity and cardiorespiratory fitness on the association among 930 men enrolled in the Aerobics Center Longitudinal Study.

Results:

A total of 124 men developed metabolic syndrome during 8974 person-years of exposure. After adjusting for covariates, men with middle and high sedentary behavior had 65% and 76% higher risks of developing metabolic syndrome, respectively, than men with low sedentary behavior (linear trend P = .011). This association remained significant after additional adjustment for activity status and cardiorespiratory fitness. Cardiorespiratory fitness and physical activity were also inversely associated with metabolic syndrome, even after adjustment for sedentary behavior.

Conclusions:

The findings highlight the importance of reducing sedentary behavior, increasing physical activity, and improving cardiorespiratory fitness for preventing metabolic syndrome.

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Becky L. Heinert, Thomas W. Kernozek, John F. Greany and Dennis C. Fater

Objective:

To determine if females with hip abductor weakness are more likely to demonstrate greater knee abduction during the stance phase of running than a strong hip abductor group.

Study Design:

Observational prospective study design.

Setting:

University biomechanics laboratory.

Participants:

15 females with weak hip abductors and 15 females with strong hip abductors.

Main Outcome Measures:

Group differences in lower extremity kinematics were analyzed using repeated measures ANOVA with one between factor of group and one within factor of position with a significance value of P < .05.

Results:

The subjects with weak hip abductors demonstrated greater knee abduction during the stance phase of treadmill running than the strong group (P < .05). No other significant differences were found in the sagittal or frontal plane measurements of the hip, knee, or pelvis.

Conclusions:

Hip abductor weakness may influence knee abduction during the stance phase of running.

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Nico W. Van Yperen

This prospective study was designed to identify psychological factors that predict career success in professional adult soccer. Post hoc, two groups were distinguished: (1) Male soccer players who successfully progressed into professional adult soccer (n = 18) and (2) Male soccer players who did not reach this level (n = 47). Differences between the two groups were examined on the basis of data gathered in the initial phase of their careers, 15 years earlier. The psychological factors that predicted career success while statistically controlling for initial performance level and demographic variables were goal commitment, engagement in problem-focused coping behaviors, and social support seeking. On the basis of their scores on the significant predictor and control variables, 84.6% of the adolescent youth players were classified correctly as successful or unsuccessful.

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Simon M. Luethi, Edward C. Frederick, Michael R. Hawes and Benno M. Nigg

The purpose of this study was to analyze the influence of footwear on the kinematics and the mechanical load on the lower extremities during fast lateral movements in tennis. The method used was a prospective study. Two types of tennis shoes were randomly distributed among 229 tennis players. The subjects were measured before starting a 3-month test period. The study showed that the kinematics of the lower extremities and internal load conditions during fast lateral movements in tennis are highly influenced by the type of shoe worn. The results further suggest that a prospective biomechanical analysis can be used to establish assumptions concerning the etiology of pain and injuries in sports related activities.

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Caroline A. Macera and Wilma Wooten

This review summarizes information on the rate of injury among adolescents who participate in specific sports or recreational activities. Injury-related mortality is high among adolescents, accounting for over 75% of the deaths occurring among those between 15 and 19 years of age, with about 5% of these deaths attributed to sports injuries. Several difficulties were encountered in conducting this review. There was no standard definition for injury, resulting in widely diverse operational definitions. The underlying denominator and time period used to obtain rates also varied widely. In spite of these difficulties, several sports were identified as particularly dangerous due to the nature of the injury: football for males and gymnastics for females. Consistent injury definitions and larger prospective studies are needed to confirm these rates and to identify risk factors.

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Colin A. Armstrong, James F. Sallis, Melbourne F. Hovell and C. Richard Hofstetter

Components of the transtheoretical model of change were examined in a prospective study of the adoption of vigorous exercise in adults. Respondents to a random mail survey were resurveyed 2 years later. Those who reported no vigorous exercise at baseline were classified as either contemplators (n = 213) or precontemplators (n = 188). Contemplators had higher baseline self-efficacy scores than precontemplators (p < .001). In multivariate analyses, baseline stage of change was a significant predictor (p < .0005) of later adoption of vigorous exercise, even after controlling for differences in age, gender, and self-efficacy. During the first 6 months postbaseline, contemplators were nearly twice as likely as precontemplators to progress to the stage of action (46% vs. 24%), and four times more likely to progress to the stage of maintenance (25% vs. 6%). Use of the transtheoretical model in the study of exercise was supported in this prospective examination of exercise in a community sample.

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Larry Tucker and Travis Peterson

Background:

This study was conducted to determine if cardiorespiratory fitness at baseline, and changes in fitness, influence risk of weight gain (≥3 kg) over 20 months. Another aim was to ascertain if potential confounding factors, including age, education, strength training, energy intake, and weight, influence risk of weight gain.

Methods:

In a prospective study of 257 women, fitness (VO2max) was assessed using a graded, maximal treadmill test at baseline and follow-up. Energy intake was measured using 7-day, weighed food records. Subjects were divided into quartiles based on fitness. Risk ratios were used to show the risk of weight gain among those who were fit at baseline compared with their counterparts.

Results:

Most women gained weight and 23% gained ≥3 kg. Mean VO2max was 35.7 ± 7.2 mL·kg−1·min−1. Women with low-fitness at baseline had 3.18 times (95% CI: 1.46 to 6.93) greater risk, and moderately fit women had 2.24 times (95% CI: 1.04 to 4.82) greater risk of weight gain than women in the high-fitness quartile. Adjusting for potential confounders had little effect on results.

Conclusions:

High levels of fitness seem to help protect middle-aged women against weight gain, whereas low and moderate fitness increase risk of weight gain over time.

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Päivi Lampinen and Riitta-Liisa Heikkinen

The purpose of this prospective study, which is part of the Finnish Evergreen project, was to study depressive symptoms and positive self-esteem in different physical activity categories among men and women aged 65 and over during an eight-year period. Only subjects (N=663) who participated in both the baseline (1988) and the follow-up (1996) interviews were selected for the analyses. Depressive symptoms and positive self-esteem were assessed using a modified version of Beck’s 13-item scale (RBDI; Raitasalo, 1995). The intensity of physical activity was assessed on a seven-point scale ranging from the performance of necessary chores only to competitive sports. In addition, lifelong physical exercise was assessed by two questions. Number of chronic diseases and marital status were obtained from the participants themselves. Gender, lifelong physical exercise, intensity of physical activity and chronic diseases were associated with depressive symptoms and self-esteem. Physically active men and women and lifelong exercisers reported fewer depressive symptoms than their sedentary counterparts both at baseline and follow-up. The self-esteem scores were fairly similar among both sexes in the different categories of physical activity in both study years. The most active women had higher self-esteem scores than the more sedentary ones. Based upon these results, physical activity and lifelong physical exercise may prevent depressive symptoms and maintain positive self-esteem in older age. Positive measures should therefore be taken to support regular physical activity among older men and women.

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Felipe Fossati Reichert, Ana Maria Batista Menezes, Jonathan Charles Kingdom Wells, Ulf Ekelund, Fabiane Machado Rodrigues and Pedro Curi Hallal

Background:

Prospective studies on physical activity (PA), diet, and body composition in adolescents are lacking, particularly outside high-income countries.

Goals:

To describe the methods used to assess these variables in the 1993 Pelotas (Brazil) Birth Cohort and to discuss the fieldwork challenges faced and alternatives to overcome them.

Methods:

In 2006–07 a subsample of the 1993 Pelotas cohort was revisited. PA was estimated using questionnaires, a combined heart-rate and motion sensor (Acti-Heart), and the ActiGraph GT1M accelerometer. Diet was investigated by questionnaire. Total body water was determined by stable isotopes. Thirty individuals had their total energy expenditure assessed by doubly labeled water. All data were collected at participants’ home.

Results:

The logistics of the fieldwork and the difficulties in undertaking the study and alternatives to overcome them are presented. Preliminary analyses show that 511 individuals were traced (response rate = 90.0%). Compliance of both adolescents and their families for the motion sensors and body-composition measurements was excellent.

Conclusions:

The authors conclude that it is feasible to carry out high-quality studies on PA in developing countries. They hope the article will be useful to other researchers interested in carrying out similar studies.

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Eileen K. Nehme, Adriana Pérez, Nalini Ranjit, Benjamin C. Amick III and Harold W. Kohl III

Background:

This quasi-experimental study assessed the effects of new workplace showers on physical activity behaviors in a sample of downtown employees in Austin, TX.

Methods:

The study design was quasi-experimental with 2 comparison groups. Data were collected via internet-based surveys before and 4 months after shower installation at 1 worksite. Differences across study groups in the ranks of change in past-week minutes of physical activity from baseline to follow-up were assessed. Adjusted odds ratios and 95% confidence intervals for reporting an increase of ≥10 min past-week physical activity and workday physical activity among those with new showers and existing showers relative to those with no showers were also assessed.

Results:

No significant differences in changes in physical activity from baseline to follow-up across study groups were found. One-quarter of participants with new workplace showers and 46.9% of those with existing workplace showers at baseline reported ever using the showers.

Conclusions:

This prospective study did not find significant changes in employee physical activity 4 months after installation of worksite showers. Worksite shower users were highly active at baseline, suggesting a possible early adopter effect, with potential for diffusion. Future studies may benefit from longer exposure times and larger samples.