Relationship Between Physical Activity and Clinical Outcomes After ACL Reconstruction.

CONTEXT: Reductions in objectively measured moderate to vigorous physical activity (MVPA) have been reported among individuals with anterior cruciate ligament reconstruction (ACLR). Self-reported measures of physical activity are commonly used to assess participation in physical activity after ACLR despite the lack of evidence to support the validity of such measures within this population. OBJECTIVE: The objective of this research was to determine the relationships between objectively measured MVPA, self-reported physical activity, and knee function among individuals with ACLR. SETTING: University laboratory. Patients (or Other Participants): Thirty-one participants with a history of ACLR (sex: 23 females and 8 males; age = 19.8 [1.4] y) and 31 matched controls (sex: 23 females and 8 males; age = 20.6 [1.7] y) enrolled in this study. INTERVENTION(S): None. MAIN OUTCOME MEASURES: Participants completed self-reported physical activity using the Tegner Activity Scale and the Marx Activity Rating Scale. Participant MVPA was objectively measured using an ActiGraph wGT3X-BT accelerometer for a 7-day period during which the monitor was worn for not less than 10 hours per day. Primary outcome measures were the amount of time spent in MVPA (minutes per week) and time spent in MVPA performed in bouts of ≥10 minutes (minutes per week). Relationships between the Tegner Activity Score, Marx Activity Rating Scale, and objectively measured MVPA variables were assessed using partial Spearman's rank correlation coefficients after controlling for activity monitor wear time. RESULTS: There were no significant relationships between objectively measured MVPA and self-reported physical activity (ρ ≤ 0.31, P ≥ .05) or self-reported knee-related function (ρ ≤ .41, P ≥ .05) among ACLR participants. CONCLUSIONS: Objectively measured physical activity is not significantly related to self-reported physical activity or self-reported knee function among individuals with a history of ACLR. Consideration of objective and self-reported physical activity within this population may provide key insights into disconnects between perception and the reality of physical activity engagement following ACLR.

Associations Among Leisure-Time Physical Activity, Gestational Weight Gain, and Postpartum Weight Retention With Varying Estimates of Prepregnancy Weight.

Prospective studies examining postpartum weight retention (PPWR) in relation to the appropriateness of gestational weight gain (GWG) and leisure-time physical activity (LTPA) during pregnancy and postpartum are lacking. While utilizing varying estimates of prepregnancy weight, we sought to prospectively examine associations among the aforementioned variables. Our sample consisted of a subset of women from the Archive for Research on Child Health Study (n = 68). Prepregnancy weight was obtained via questionnaire and birth certificates. GWG (2 estimates) was calculated by subtracting prepregnancy weight estimates from weight at delivery and classified as "excess" or "not excess." Pregnancy and postpartum LTPA were self-reported and dichotomized at recommended levels. Prepregnancy weight estimates were subtracted from self-reported postpartum weight to calculate 2 estimates of PPWR at 6 months. Linear regression was used to examine relationships among GWG and LTPA, and PPWR. Estimates of excess GWG were associated with increased PPWR (mean difference = 3.3-8.9 kg), even after adjustment for prepregnancy body mass index and breastfeeding. Meeting pregnancy and postpartum LTPA recommendations did not significantly predict PPWR. Our findings highlight the importance of encouraging appropriate GWG and provide insight into the impact varying estimates of prepregnancy weight may have when exploring associations among these variables.

Age related differences in the validity of the OMNI perceived exertion scale during lifestyle activities.

PURPOSE: The OMNI perceived exertion scale was developed for children to report perceived effort while performing physical activity; however no studies have formally examined age-related differences in validity. This study evaluated the validity of the OMNI-RPE in 4 age groups performing a range of lifestyle activities. METHODS: 206 participants were stratified into four age groups: 6-8 years (n = 42), 9-10 years (n = 46), 11-12 years (n = 47), and 13-15 years (n = 71). Heart rate and VO2 were measured during 11 activity trials ranging in intensity from sedentary to vigorous. After each trial, participants reported effort from the OMNI walk/run scale. Concurrent validity was assessed by calculating within-subject correlations between OMNI ratings and the two physiological indices. RESULTS: The average correlation between OMNI ratings and VO2 was 0.67, 0.77, 0.85, and 0.87 for the 6-8, 9-10, 11-12 and 13-15 y age groups, respectively. CONCLUSION: The OMNI RPE scale demonstrated fair to good evidence of validity across a range of lifestyle activities among 6- to 15-year-old children. The validity of the scale appears to be developmentally related with RPE reports closely reflecting physiological responses among children older than 8 years.