Biopsychosocial responses to 30 minutes of walking in emerging adult women with different physical activity habits
Authors:   , Hawkins Jillian , Milner Clare E. 
Published: September 2022

Half of emerging adults do not meet the physical activity guidelines, which is a risk for lifestyle diseases. Emerging adulthood, 18 to 29 years of age, is a period of transition making it an opportune time for incorporating physical activity habits. Some reasons or biopsychosocial barriers to physical activity that sedentary adults may not participate in physical activity include physiological difficulty, risk of injury, and negative perceptions of physical activity. The purpose of the study was to determine which of these biopsychosocial barriers to physical activity were greatest in sedentary emerging adult women compared to active emerging adult women. Thirty emerging adult women, 15 sedentary and 15 active, individuals were recruited. During the first visit, participants answered questionnaires about their perceptions of physical activity. Then, they completed a maximal exercise test. For the second visit, retroreflective markers were placed on the participant. Three-dimensional gait analysis was performed using a motion capture system and ground reaction force data. Participants walked across the gait laboratory for 5 trials at 1.4 meters per second (m/s) ± 5%. Next, they walked for 30 minutes on a treadmill, while oxygen consumption (VO2) and heart rate (HR) were collected. Participants were asked to walk a self-selected pace where they could "talk but not sing" per Centers for Disease Control and Prevention's (CDC) physical activity intensity recommendation. RPE was measured every 5 minutes during the 30-minute walk. Then, they walked across the gait laboratory for 5 additional trials. Means, standard deviations, and effect sizes were determined for %VO2max, %HRmax, RPE and walking biomechanical variables. Independent t-tests were used to compare the %VO2max, peak knee flexion angle and extensor moment in sedentary and active emerging adult women. Additionally, dependent t-tests were used to compare peak knee flexion angle and extensor moment before and after 30 minutes of walking in both sedentary and active women. Medians, interquartile ranges, and effect sizes were determined for barriers and benefits questionnaire scores. Mann Whitney U tests were used to compare barriers and benefits scores from the Exercise Benefits/Barriers Scale' in the sedentary and active groups. 'For physiological difficulty, %VO2max was similar between sedentary and active emerging adult women. This indicates that it was not a biopsychosocial barrier to physical activity in sedentary emerging adult women. For walking biomechanics associated with PFP, peak knee flexion angle was similar between groups. Peak internal knee extensor moment was significantly smaller in sedentary emerging adult women compared to active. A smaller peak knee extensor moment is associated with increased risk of PFP. Therefore, walking biomechanics at baseline may be a biopsychosocial barrier to physical activity in sedentary emerging adult women compared to active emerging adult women. Following 30 minutes of walking, peak knee flexion angle was significantly higher and peak knee extensor moment was similar before 30 minutes of walking in both groups. These results suggest that the stress on the patellofemoral joint likely did not increase following 30 minutes of walking. Thus, our findings suggest that both sedentary and active young women can walk for 30 minutes without detrimental changes to walking biomechanics that may increase their risk of PFP. For perceived barriers to and benefits of physical activity, sedentary emerging adult women had significantly higher barriers scores and lower benefits scores compared to active. This indicates that sedentary emerging adult women perceived significantly more barriers to and fewer benefits of physical activity than active emerging adult women. Thus, negative perceptions of physical activity were a biopsychosocial barrier to physical activity in sedentary emerging adult women. In conclusion, negative perceptions of physical activity were the greatest biopsychosocial barrier to physical activity followed by walking biomechanics associated with PFP in sedentary emerging adult women. Physiological difficulty was not a biopsychosocial barrier to physical activity in sedentary emerging adult women. These findings can inform focused physical activity interventions to target negative perceptions of physical activity in sedentary emerging adult women. This study is the first step to understanding biopsychosocial barriers to meeting physical activity guidelines in emerging adult women to increase physical activity and reduce risks for lifestyle diseases.