Search Results

You are looking at 1 - 10 of 20 items for

  • Author: Patty S. Freedson x
  • Refine by Access: All Content x
Clear All Modify Search
Restricted access

Patty S. Freedson

Precise quantification of physical activity is necessary in order to evaluate the relationship between physical activity and various types of disease and/or risk factors associated with disease. With the emergence of the study of the origins of coronary heart disease risk factors in children, it is imperative that accurate measurement of physical activity in the pediatric population be obtained. This review critically evaluates various field measures of physical activity in children including motion sensors, questionnaires, and heart rate. A new heart-rate quantification procedure is also presented that may provide an index of the quality of physical activity.

Restricted access

Ann F. Maliszewski and Patty S. Freedson

In this study, running economy differences between boys and men at a common speed (ABS = 9.6 kph) and at a relative speed adjusted for body size (REL = 3.71 leg lengths per second) were examined. The caloric cost relative to mass was significantly higher for the boys for ABS (men = .17, boys = .20), but not for REL (both .19). The relative heart rate (%HRmax) and ventilatory equivalent were higher for the boys at ABS, but not at REL. Boys had significantly higher stride frequencies in both conditions. Stride length/leg length was greater for boys during ABS, and for men during REL. Respiratory exchange ratios (RERs) were not different at ABS (men = .94, boys = .96), but during REL, boys had a significantly lower RER (.93 vs. .98). Running economy differences between adults and children are reduced when speeds are adjusted relative to body size. This model may be useful for identifying developmentally based differences in the physiology and biomechanics associated with exercise.

Restricted access

James R. Morrow Jr. and Patty S. Freedson

This review summarizes the research relating physical activity to aerobic fitness among adolescents. A brief description of commonly used physical activity and aerobic fitness measures is presented, followed by an interpretation of the literature that suggests a small to moderate relationship between physical activity and aerobic fitness in this population (typical correlation of .16-17). Dose-response data are lacking, which makes it difficult to offer definitive conclusions concerning the amount of physical activity necessary to elicit change in aerobic capacity. Nevertheless, recommendations about the type, amount, and quality of physical activity for adolescents are presented. Recommendations are based on a summary of the research data on daily physical activity and aerobic fitness in adolescents. Further research is needed to investigate the association between habitual physical activity and aerobic fitness in adolescents where the a priori goal is to identify a threshold of daily physical activity necessary for an aerobic benefit associated with enhanced health.

Restricted access

Heidi L. Keller, Stephen E. Tolly, and Patty S. Freedson

The sport of wrestling often encourages participants to engage in extreme weight loss practices in order to compete in a weight class one to three weight categories below normal weight. This review discusses the prevalence of the problem, methods wrestlers use to accomplish weight loss, and the health and performance consequences of rapid weight loss, with particular emphasis on weight cycling and minimal safe wrestling weight assessment. Some useful and practical recommendations for minimizing extreme weight loss practices are presented. Several state wrestling associations have adjusted their rules and regulations based on recommendations by organizations such as the American College of Sports Medicine to reduce the prevalence of the problem. Nevertheless, extreme weight loss continues to be a concern among health professionals, particularly with regard to health and performance.

Restricted access

Joseph Hamill, Patty S. Freedson, Priscilla M. Clarkson, and Barry Braun

This study involved an 8-day protocol to determine the effects of delayed-onset muscle soreness (DOMS) on the mechanics of the lower extremity and on oxygen consumption during level running. On Day 1 the subjects, 10 healthy female recreational runners, were administered a treadmill max V̇O2 test. They completed a 30-min downhill run on Day 3 to induce muscle soreness. On Days 2, 5, and 8 they completed a 15-min level run at a speed corresponding to 80% of V̇O2max. Subsequent to each run the subjects completed a muscle soreness questionnaire and a blood sample was taken for creatine kinase (CK) analysis. Data analysis revealed statistically significant between-day differences for perceived muscle soreness and CK activity. However, metabolic cost was not different between days. There were significant differences between days in maximum ankle support dorsiflexion and plantar flexion and maximum knee flexion during both support and swing. None of the global parameters describing the total stride produced significant differences between Days 2 and 5. Therefore DOMS appeared to have little effect on V̇O2 and a small effect on the kinematics of the lower extremity.

Restricted access

David R. Bassett, Patty S. Freedson, and Dinesh John

In recent years, there has been tremendous growth in the use of wearable activity trackers in biomedical research. Activity trackers are also becoming more popular with consumers, who are able to share their data with researchers and practitioners. Steps per day is a useful variable that is estimated from most wearable activity trackers. It has intuitive meaning, is strongly associated with health variables, and has the potential to be standardized across devices. Activity trackers and other wearable medical devices could provide new information on health-related behaviors and their interaction with genetic and environmental variables. If integrated into medical practice, wearable technologies could help motivate patients to change their health behaviors and might eventually be used to diagnose medical conditions. The convergence of wearable medical devices, computer applications, smart phones, and electronic medical records could influence the practice of lifestyle medicine.

Restricted access

Ann F. Maliszewski, Patty S. Freedson, Chris J. Ebbeling, Jill Crussemeyer, and Kari B. Kastango

The Caltrac accelerometer functions as either an activity monitor that provides activity counts based on vertical acceleration as the individual moves about, or as a calorie counter in which the acceleration units are used in conjunction with body size, age, and sex to estimate energy expenditure. This study compared VO2 based energy expenditure with Caltrac estimated energy expenditure during three speeds of treadmill walking in children and adults. It also tested the validity of the Caltrac to differentiate between high and low levels of walking activity (activity counts). Ten boys and 10 men completed three randomly assigned walks while oxygen consumption was monitored and Caltrac estimates were obtained. The results indicate that the Caltrac does not accurately predict energy expenditure for boys and men across the three speeds of walking. Although there were no significant differences between actual and predicted energy expenditure values, the standard errors of estimate were high (17-25%) and the only significant correlation was found for men at the fastest walking speed (r=.81). However, the 95% confidence intervals of the activity counts and energy expenditure estimates from the Caltrac support its use as an activity monitor during walking.

Restricted access

Juliane R. Fenster, Patty S. Freedson, Richard A. Washburn, and R. Curtis Ellison

The relationship between physical activity measured using the LSI (Large Scale Integrated Activity Monitor), and questionnaire, with physical work capacity 170 (PWC 170) and aerobic capacity (peak V̇O2) was evaluated in 6- to 8-year-old children (n = 18). The mean (± SD) peak V̇O2 was 44.1 ± 5.6 ml • kg−1 • min−1. Peak V̇O2 was not significantly different for children (n = 8) who had completed two treadmill trials (45.4 vs. 43.5 ml • kg−1 • min−1; R = 0.67, p<0.05). The log LSI expressed as counts per hour (M ± SD = 2.1 ±.22 cts/hr) was the only activity method significantly related to peak V̇O2 (r = 0.59, p<0.05). The correlation between peak V̇O2 with the questionnaire was positive but nonsignificant (r = 0.20). PWC 170 was not related to peak V̇O2 (r = 0.21) or the activity variables (r = 0.12 questionnaire; r = 0.18 log LSI). When the group was divided into high and low peak V̇O2 groups (high: M = 48.8 ml • kg−1 • min−1; low: M = 39.5 ml • kg−1 • min−1), the log LSI was able to distinguish significant differences in activity levels (high: 2.23 ±. 19 cts/hr; low: 1.99±.19 cts/hr). This study suggests that activity measured with the LSI and aerobic capacity are related in this sample of 6- to 8-year-old children.

Restricted access

Sofiya Alhassan, Kate Lyden, Cheryl Howe, Sarah Kozey Keadle, Ogechi Nwaokelemeh, and Patty S. Freedson

This study examined the validity of commonly used regression equations for the Actigraph and Actical accelerometers in predicting energy expenditure (EE) in children and adolescents. Sixty healthy (8–16 yrs) participants completed four treadmill (TM) and five self-paced activities of daily living (ADL). Four Actigraph (AG) and three Actical (AC) regression equations were used to estimate EE. Bias (±95% CI) and root mean squared errors were used to assess the validity of the regression equations compared with indirect calorimetry. For children, the Freedson (AG) model accurately predicted EE for all activities combined and the Treuth (AG) model accurately predicted EE for TM activities. For adolescents, the Freedson model accurately predicted EE for TM activities and the Treuth model accurately predicted EE for all activities and for TM activities. No other equation accurately estimated EE. The percent agreement for the AG and AC equations were better for light and vigorous compared with moderate intensity activities. The Trost (AG) equation most accurately classified all activity intensity categories. Overall, equations yield inconsistent point estimates of EE.

Restricted access

James F. Sallis, Wendell C. Taylor, Marsha Dowda, Patty S. Freedson, and Russell R. Pate

Correlates of physical activity were examined in young people in grades 1 through 12, and analyses were conducted separately for eight age/grade and sex subgroups. Twenty-one explanatory variables were assessed by parental report. Physical activity was assessed in 781 young people via parent report, and 200 wore an accelerometer for seven days. Between 11% and 36% of parent-reported child vigorous physical activity was explained. The most consistent correlates were peer support and use of afternoon time for active rather than sedentary recreation. Peer support was the only significant correlate of objectively monitored activity in multiple subgroups.