The Effects of Cadence Manipulation on Joint Kinetic Patterns and Stride-to-Stride Kinetic Variability in Female Runners.

Altering running cadence is commonly done to reduce the risk of running-related injury/reinjury. This study examined how altering running cadence affects joint kinetic patterns and stride-to-stride kinetic variability in uninjured female runners. Twenty-four uninjured female recreational runners ran on an instrumented treadmill with their typical running cadence and with a running cadence that was 7.5% higher and 7.5% lower than typical. Ground reaction force and kinematic data were recorded during each condition, and principal component analysis was used to capture the primary sources of variability from the sagittal plane hip, knee, and ankle moment time series. Runners exhibited a reduction in the magnitude of their knee extension moments when they increased their cadence and an increase in their knee extension moments when they lowered their cadence compared with when they ran with their typical cadence. They also exhibited greater stride-to-stride variability in the magnitude of their hip flexion moments and knee extension moments when they deviated from their typical running cadence (ie, running with either a higher or lower cadence). These differences suggest that runners could alter their cadence throughout a run in an attempt to limit overly repetitive localized tissue stresses.

The role of food and activity environment in a bariatric surgery population: impact on postoperative weight loss.

BACKGROUND: Food and activity factors may have an impact on weight in the general population, but little is known about how this affects postbariatric surgery weight loss. OBJECTIVES: To understand the impact of environmental food and activity factors on weight loss after bariatric surgery. SETTING: A multidisciplinary integrated health system with an accredited bariatric surgery program. METHODS: An institutional review board-approved retrospective review of patients who underwent bariatric surgery from 2001-2018 was completed. Food security, food retailers, and activity factors associated with postoperative percentage of total body weight loss (TBWL) at short-term (1-2 yr), medium-term (3-5 yr), and long-term (≥6 yr) follow-up were evaluated. RESULTS: Overall, 1673 patients were included; 90% experienced ≥20% TBWL in the short term and 65% in the long term. No differences in mean TBWL were observed for food deserts or areas with high versus low food insecurity. Mean TBWL was significantly different for low versus high healthy food density (32.5% versus 33.4%, P = .024) and low versus high fitness facility density (32.6% versus 33.4%, P = .048) at short-term follow-up. Increased mean TBWL was observed for counties with more versus less exercise opportunities at short and medium-term follow-up (33.4% versus 32.5%, P = .025; 31.2% versus 29.7%, P = .019). CONCLUSION: Patients experienced significant TBWL after bariatric surgery. Living in a food desert or area with high food insecurity did not significantly impact mean TBWL. Healthy food density, fitness facility density, and exercise opportunities had a short- to medium-term impact on TBWL. These data can be used to support patients to maximize the benefits of bariatric surgery.