What is the Minimum Step Rate Required to Achieve Moderate-Intensity Walking Overground in Adolescent Girls?

BACKGROUND: In order to promote walking, researchers have sought to identify the required step rate to maintain a health-enhancing walking intensity However, there is limited evidence regarding the stepping rate required to promote moderate-intensity walking in adolescent girls. PURPOSE: To identify the step rate equivalent to moderate-intensity physical activity (MPA) in adolescent girls and to explore the influence that different anthropometric measures may have on the step rate equating to MPA in this population. METHODS: A total of 56 adolescent girls (mean age = 13.8[0.7] y) were recruited to the study. Anthropometric variables and resting metabolic rate were assessed, followed by 3 overground walking trials on a flat surface at approximately 2, 3, and 4 mph, each lasting a minimum of 4 minutes. Oxygen uptake was assessed using a portable gas analyzer and subsequently converted into metabolic equivalents (METs). Step count was assessed by real-time direct observation hand tally. RESULTS: Employing the linear regression between step rate and METs (r2 = .20, standard error of estimates = 0.003) suggests that 120 steps per minute was representative of an MPA (3 METs) equating to 7200 steps in 60 minutes. Multiple regression and mixed-model regression confirmed weight-related variables and maturity were significant predictors of METs (P < .01). CONCLUSION: The results suggest that, at population level, a step rate of 120 steps per minute may be advocated to achieve MPA in adolescent girls; although, due to the small sample size used, caution should be applied. At an individual level, other factors, such as age and weight, should be considered.

Real World, Real People: Can We Assess Walking on a Treadmill to Establish Step Count Recommendations in Adolescents?

BACKGROUND: Currently, it is not known how much walking should be advocated for good health in an adolescent population. Step count recommendations for minimum time in moderate-intensity activity have been translated predominantly from treadmill walking. PURPOSE: To compare the energy cost of walking on a treadmill with overground walking in adolescent girls. METHODS: A total of 26 adolescent girls undertook resting metabolic measurements for individual determination of 1 metabolic equivalent using indirect calorimetry. Energy expenditure was subsequently assessed during treadmill and overground walking at slow, moderate, and fast walking speeds for 4 to 6 minutes. Treadmill step rates were matched overground using a metronome. RESULTS: The energy cost of treadmill walking was found to be significantly greater than and not equivalent to overground walking at 133 steps per minute; (equivalent to the fast walking pace): V˙O2 3.90 (2.78-5.01), P < .001, mean absolute percentage error (MAPE) = 18.18%, and metabolic equivalent 0.77 (0.54-1.00), P < .001, MAPE = 18.16%. The oxygen cost per step (V˙O2 mL·step-1) was significantly greater and not equivalent on the treadmill at 120 and 133 steps per minute: 0.43 (0.12-0.56), P < .05, MAPE = 10.12% versus 1.40 (1.01-1.76), P < .001, MAPE = 17.64%, respectively. CONCLUSION: The results suggest that there is a difference in energy cost per step of walking on a treadmill and overground at the same step rate. This should be considered when utilizing the treadmill in energy expenditure studies. Studies which aim to provide step recommendations should focus on overground walking where most walking activity is adopted.

Walking on sunshine: scoping review of the evidence for walking and mental health.

BACKGROUND/OBJECTIVES: Walking has well-established positive relationships with, and effects on, physical health. In contrast, while poor mental health contributes substantially to global health burden, an overview of the benefits from walking has not previously been published. We aimed to scope the literature and present what is known, and highlight what is not known, about walking and mental health. METHODS: Design: Scoping review. DATA SOURCES: Ovid (Medline), ProQuest, Web of Science.Screening and reporting: 13 014 records were identified and screened by a team of researchers. Included full texts were analysed and reported according to mental health outcome. RESULTS: For the 8 mental health outcomes (identified a priori), there were a total of 5 systematic reviews and 50 individual papers included. Depression had the most evidence and existing systematic reviews were reported. Evidence for anxiety, psychological stress, psychological well-being, subjective well-being and social isolation and loneliness varied in volume and effectiveness, but no harmful effects were identified. There were no studies for walking and resilience. The setting and context of walking seems to be important variables. CONCLUSION: The evidence base that suggests walking benefits mental health is growing, but remains fragmented and incomplete for some important outcomes. Policy and national guidelines should promote the known mental health benefits of increased walking and future research should directly address the gaps we have identified.

A longitudinal examination of the influence of maturation on physical self-perceptions and the relationship with physical activity in early adolescent girls.

This longitudinal study investigated the influence of maturation on physical self-perceptions and the relationship with physical activity in early adolescent girls (N=150; mean age=12.79+/-0.31). Physical characteristics were measured and participants completed the Physical Activity Questionnaire for Children, the Children and Youth Physical Self-Perception Profile and the Pubertal Development Scale on two occasions 12 months apart. The results demonstrated a decrease in overall physical activity levels over 12 months which was not influenced by maturational status or physical characteristics. Additional analysis indicated that physical self-perceptions partially accounted for the explained variance in physical activity change, with physical condition being an important individual predictor of physical activity. Further analysis indicated that body mass was an important individual predictor of changes in perceptions of body attractiveness and physical self-worth. At this age maturation has a limited influence on the physical activity behaviours of early adolescent girls and although the variance in physical activity was partly accounted for by physical self-perceptions, this was a relatively small contribution and other factors related to this drop in physical activity need to be considered longitudinally.