Walking cadence is a new monitoring strategy used to increase bouts of time at moderate intensity. Inactive older adults were instructed to walk 150 min per week at no specified intensity during phase one. In phase two, the intervention group (N = 23) received instructions on how to reach moderate intensity, using a pedometer and an individualized walking cadence, while the control group (N = 22) did not. The main outcomes were time at moderate intensity and moderate intensity in 10-min bouts. During phase two only the intervention group increased time at moderate intensity and moderate intensity in 10-min bouts compared with phase one and compared with the control group (p ≤ .01). Older adults can increase time walked at moderate intensity in 10-min bouts weekly by using individually prescribed walking cadence, a pedometer to track intensity, and practicing walking at this cadence.
Jana Slaght, Martin Sénéchal and Danielle R. Bouchard
Danielle R. Bouchard, K. Ashlee McGuire, Lance Davidson and Robert Ross
One hundred forty-six abdominally obese adults age 60–80 yr were studied to investigate the interaction between cardiorespiratory fitness (CRF) and obesity on functional limitation. Obesity was determined by fat mass (FM), CRF was determined by a maximal treadmill test, and functional limitation was based on 4 different tasks that are predictive of subsequent disability. Both FM (r = –.34, p ≤ .01) and CRF (r = .54, p ≤ .01) were independently associated with functional limitation in bivariate analysis. After further control for sex, age, and the interaction term (CRF × FM), FM was no longer independently associated with functional limitation (p = .10). Analyses were also based on sex-specific tertiles of FM and CRF. The referent group demonstrated significantly lower functional limitation than the low-CRF/low-FM and the low-CRF/high-FM groups (both p ≤ .05). These results highlight the value of recommending exercise for abdominally obese adults.
Fagner Serrano, Jana Slaght, Martin Sénéchal, Todd Duhamel and Danielle R. Bouchard
Many international agencies recommend using 40% of VO2reserve to individually prescribe moderate aerobic intensity to achieve health benefits. Few studies have evaluated the walking cadence needed to reach that intensity for older adults. A total of 121 apparently healthy adults with an average age of 69 and an average VO2peak of 24.1 ± 6.7 ml/kg/min (women) and 28.9 ± 9.1 ml/kg/min (men) were studied. Walking cadence at moderate intensity was established when participants reached 40% of VO2reserve on an indoor flat surface using a portable metabolic cart. Other clinical variables potentially associated with walking cadence were collected to create a clinical algorithm. Mean walking cadence to reach moderate intensity was 115 ± 10 steps per minute. The best algorithm to predict the walking cadence needed to reach moderate intensity in this sample was 113.6–0.23 (body weight in kg) + 0.21 (self-selected walking cadence in steps per minute).
Serge Beliaeff, Danielle R. Bouchard, Christophe Hautier, Martin Brochu and Isabelle J. Dionne
This cross-sectional study examined the relationship between arm and leg muscle mass and isometric muscle strength in 465 well-functioning women and 439 well-functioning men from the NuAge cohort, age 67–84 years. Leg and arm muscle mass and body fat were measured by dual-X-ray absorptiometry. Maximum voluntary isometric strength of knee extensors and elbow flexors was measured using the belt-resisted method and a handheld dynamometer, respectively. The regression model including leg muscle mass, physical activity level, age, height, and body fat explained 14% of the variance in quadriceps strength in men and 11% in women (p < .001), whereas the model including arm muscle mass and the same covariates elucidated 40% and 28%, respectively, of the variance in biceps strength (p < .001). These results suggest that muscle mass does not play a crucial role in the variations of isometric muscle strength in well-functioning elderly.
Danielle R. Bouchard, Shaelyn Strachan, Leslie Johnson, Fiona Moola, Radhika Chitkara, Diana McMillan, Semone Myrie and Gordon Giesbrecht
Our objective was to test the feasibility of sharing treadmill workstations among office workers to reduce time spent at low intensity and explore changes in health outcomes after a 3-month intervention.
Twenty-two office workers were asked to walk 2 hours per shift on a shared treadmill workstation for 3 months. Physical activity levels (ie, low, light, moderate, and vigorous), health-related measures (eg, sleep, blood pressure), treadmill usage information, and questions regarding participants’ expectation and experiences were collected.
Physical activity time at low intensity during workdays was reduced by 20.1% (P = .007) in the 71% of participants completing the study. Participants were 70% confident that they would keep using the treadmill workstations. Interestingly, systolic blood pressure, diastolic blood pressure, and sleep quality scores were significantly improved (P < .05).
The use of such equipment to replace a few hours of sitting is feasible and might offer important health benefits.