The purpose of this study was to assess the relative and absolute reliability of metabolic measures of energy expenditure and gait speed during overground walking in older adults with mobility limitations. Thirty-three (mean age [SD] = 76.4 [6.6] years; 66% female) older adults with slow gait participated. Measures of energy expenditure and gait speed were recorded during two 6-min bouts of overground walking (1 week apart) at a self-selected “usual” walking pace. The relative reliability for all variables was excellent: ICC = .81−.91. Mean differences for five of the six outcome variables was less than or equal to the respected SEM, while all six mean differences fell below the calculated MDC95. Clinicians and researchers can be confident that metabolic measures of energy expenditure and gait speed in older adults with slow walking speeds can be reliably assessed during overground walking, providing an alternative to traditional treadmill assessments.
David M. Wert, Jessie M. VanSwearingen, Subashan Perera and Jennifer S. Brach
Susan Vincent Graser, Robert P. Pangrazi and William J. Vincent
The purpose was to determine if waist placement of the pedometer effected accuracy in normal, overweight, and obese children, when attaching the pedometer to the waistband or a belt.
Seventy-seven children (ages 10-12 y) wore five pedometers on the waistband of their pants and a belt at the following placements: navel (NV), anterior midline of the right thigh (AMT), right side (RS), posterior midline of the right thigh (PMT), and middle of the back (MB). Participants walked 100 steps on a treadmill at 80 m · min−1.
The RS, PMT, and MB sites on the waistband and the AMT and RS sites on the belt produced the least error.
Of these sites the RS placement is recommended because of the ease of reading the pedometer during activity. Using a belt did not significantly improve accuracy except for normal weight groups at the NV placement site.
Nora E. Miller, Scott J. Strath, Ann M. Swartz and Susan E. Cashin
This study examined the predictive validity of accelerometers (ACC) to estimate physical activity intensity (PAI) across age and differences in intensity predictions when expressed in relative and absolute PAI terms. Ninety adults categorized into 3 age groups (20–29, 40–49, and 60–69 yr) completed a treadmill calibration study with simultaneous ACC (7164 Actigraph) and oxygen-consumption assessment. Results revealed strong linear relations between ACC output and measured PAI (R2 = .62–.89) across age and similar ACC cut-point ranges across age delineating absolute PAI ranges compared with previous findings. Comparing measured metabolic equivalents (METs) with estimated METs derived from previously published regression equations revealed that age did not affect predictive validity of ACC estimates of absolute PAI. Comparing ACC output expressed in relative vs. absolute terms across age revealed substantial differences in PAI ACC count ranges. Further work is warranted to increase the applicability of ACC use relative to PAI differences associated with physiological changes with age.
Linda Schücker, Christian Knopf, Bernd Strauss and Norbert Hagemann
The aim of this study was to examine differentiated effects of internally focused attention in endurance sports. Thirty-two active runners ran 24 min on a treadmill at a fixed speed of moderate intensity. For each 6-min block, participants had to direct their attention on different internal aspects (movement execution, breathing, or feeling of the body) or received no instructions. Oxygen consumption (VO2) was measured continuously to determine running economy. Results revealed that the different internal focus instructions had differentiated effects on VO2: A focus on breathing as well as a focus on the running movement led to higher VO2 than a focus on feeling of the body which showed similar VO2 as the control condition. We conclude that an internal focus of attention is solely detrimental to performance when directed to highly automated processes (e.g., breathing or movement). However, an internal focus on how the body feels during exercise does not disrupt movement efficiency.
Regina R. Buccello-Stout, Ronita L. Cromwell, Jacob J. Bloomberg and Elbert B. Whorton
The goal of this study was to determine if exposure to sensorimotor adaptation training improved head stabilization in older adults. Sixteen participants, age 66–81 yr, were assigned at random to the control group (n = 8) or the experimental group (n = 8). Both groups first completed 6 trials of walking a foam pathway consisting of a moveable platform that induced a lateral perturbation during walking. Head-in-space and trunk-in-space angular velocities were collected. Participants from both groups then trained twice per week for 4 wk. Both groups walked on a treadmill for 20 min. The control group viewed a static scene. The experimental group viewed a rotating visual scene that provided a perceptual-motor mismatch. After training, both groups were retested on the perturbation pathway test. The experimental group used a movement strategy that preserved head stabilization compared with the controls (p < .05). This training effect was not retained after 4 wk.
Sarah M. Markowitz and Shawn M. Arent
This study examined the relationship between exertion level and affect using the framework of opponent-process theory and the dual-mode model, with the Activation-Deactivation Adjective Checklist and the State Anxiety Inventory among 14 active and 14 sedentary participants doing 20 min of treadmill exercise at speeds of 5% below, 5% above, and at lactate threshold (LT). We found a significant effect of time, condition, Time × Condition, and Time × Group, but no group, Group × Condition, or Time × Group × Condition effects, such that the 5% above LT condition produced a worsening of affect in-task compared with all other conditions whereas, across conditions, participants experienced in-task increases in energy and tension, and in-task decreases in tiredness and calmness relative to baseline. Posttask, participants experienced mood improvement (decreased tension, anxiety, and increased calmness) across conditions, with a 30-min delay in the above LT condition. These results partially support the dual-mode model and a modified opponent-process theory.
Mark Watsford and Aron Murphy
This research examined the effects of respiratory-muscle (RM) training on RM function and exercise performance in older women. Twenty-six women (60–69 yr of age) were assessed for spirometry, RM strength (maximal inspiratory and expiratory pressure), inspiratory-muscle endurance, and walking performance to a perceived exertion rating of “hard.” They were randomly allocated to a threshold RM training group (RMT) or a nonexercising control group (CON) for 8 wk. After training, the 22% (inspiratory) and 30% (expiratory) improvements in RM strength in the RMT group were significantly higher than in the CON group (p < .05). The RMT group also displayed several significant performance improvements, including improved within-group treadmill performance time (12%) and reductions in submaximal heart rate (5%), percentage of maximum voluntary ventilation (16%), and perceived exertion for breathing (8%). RM training appears to improve RM function in older women. Furthermore, these improvements appear to be related to improved submaximal exercise performance.
Barbara Resnick, Kathleen Michael, Marianne Shaughnessy, Eun Shim Nahm, Susan Kopunek, John Sorkin, Denise Orwig, Andrew Goldberg and Richard F. Macko
Self-report measures of physical activity have well-known drawbacks, and physiologic measures alone do not account for behavioral variables important in the perception and performance of physical activity. Therefore, we considered multiple measures to quantify physical activity in community-dwelling men and women with chronic stroke.
This analysis included data from a volunteer sample of 87 individuals at least 6 months poststroke. Physical activity was measured using self-report questionnaires, step activity monitors, self-efficacy expectations related to exercise, and VO2peak from treadmill testing, and a model of physical activity was tested.
Most of the variance in objective physical activity was explained by VO2peak, and most of the variance in subjective physical activity was explained by self-efficacy expectations. There were significant discrepancies between subjective and objective findings.
This study helps to understand the perspective of stroke survivors with regard to physical activity.
Tanya M.F. Scarapicchia, Catherine M. Sabiston, Ross E. Andersen and Enrique Garcia Bengoechea
Young inactive healthy-weight females (n = 42) were randomly assigned to exercise at a self-selected pace on a treadmill beside a confederate who was providing either intrinsic or externally regulated verbal primes. Heart rate (HR), rating of perceived exertion (RPE), percentage of time spent in moderate-to-vigorous physical activity (MVPA), and exercise continuance were recorded. Participants completed a self-report questionnaire assessing mood pre- and postexercise session and postexercise motivational outcomes. The intrinsic motivation group reported higher RPE values after 8 min of exercise, had higher recorded HR measures at all 5 recorded time points, exercised at a higher %HR max, spent more time in MVPA, and were more likely to continue to exercise than participants in the externally regulated motivation group. A time effect was noted for vigor. Based on these findings, exercise motivation can be “contagious” through verbal primes, suggesting that exercising with or around intrinsically motivated individuals may have beneficial outcomes.
Benjamin A. Sibley and Sian L. Beilock
In the current work we asked whether executive function, as measured by tests of working memory capacity, might benefit from an acute bout of exercise and, more specifically, whether individuals who are lower or higher in working memory to begin with would be more or less affected by an exercise manipulation. Healthy adults completed working memory measures in a nonexercise (baseline) session and immediately following a 30-min self-paced bout of exercise on a treadmill (exercise session). Sessions were conducted 1 week apart and session order was counterbalanced across participants. A significant Session × Working Memory interaction was obtained such that only those individuals lowest in working memory benefited from the exercise manipulation. This work suggests that acute bouts of exercise may be most beneficial for healthy adults whose cognitive performance is generally the lowest, and it demonstrates that the impact of exercise on cognition is not uniform across all individuals.