Pamela D. Swan
Melissa J. Benton and Pamela D. Swan
Research suggests that ingesting protein after resistance exercise (RE) increases muscle protein synthesis and results in greater muscle gains. The effect on energy expenditure and substrate utilization, however, is unclear. This study evaluated the effect of RE and post exercise protein on recovery energy expenditure and substrate utilization in 17 women (age 46.5 ± 1.2 y). A whey-protein supplement (120 kcal, 30 g protein) was ingested immediately after 1 bout of RE (PRO) and a non caloric placebo after another (PLA). VO2 and respiratory-exchange ratio (RER) were measured before and for 120 min after each exercise session. RE resulted in a significant increase in VO2 that persisted through 90 min of recovery (P < 0.01) and was not affected by protein supplementation. RE significantly lowered RER, resulting in an increase in fat oxidation for both PLA and PRO (P < 0.01). For PRO, however, RER returned to baseline values earlier than for PLA, resulting in a reduced fat-oxidation response (P = 0.02) and earlier return to pre exercise baseline values than for PLA. Substrate utilization was significantly different between conditions (P = 0.02), with fat contributing 77.76% ± 2.19% for PLA and 72.12% ± 2.17% for PRO, while protein oxidation increased from 17.18% ± 1.33% for PLA to 20.82% ± 1.47% for PRO. Post exercise protein did not affect energy expenditure, but when protein was available as an alternate fuel fat oxidation was diminished. Based on these findings it might be beneficial for middle-aged women to delay protein intake after RE to maximize fat utilization.
Kristin J. Heumann and Pamela D. Swan
Jumping rope (JR) is known to enhance Os Calcis Stiffness Index (OCSI) in postpubertal girls; however the effects in prepubescent girls are unknown.
Qualitative Ultrasound (QUS) indices were compared between competitive JRs (N = 19) and normally active (NA, N = 18) girls 9–12 years old.
Heel QUS, height, weight, percent body fat (bioelectrical impedance), and Tanner Sex Stage (self-report) were measured.
JR were significantly younger and had less body fat than NA (p < .01). No other between group differences were found. OCSI was not different between groups even after correcting for fat mass (p > 0.3). Broadband attenuation (BUA) was correlated with Tanner stage (R > .40; p = .01).
QUS of the heel bone is more related to pubertal status than to JR participation in young girls. Prepubertal girls who perform high intensity jumping have similar bone quality measures as normally active girls.
Sarah J. Wherry, Cheryl Der Ananian and Pamela D. Swan
Background: This study evaluated the feasibility and effectiveness of a home-based exercise intervention using the Wii Fit Plus®. Methods: A randomized, controlled trial of 24 women (age 53.6 [5.4] y) was used to assess compliance and changes in balance over 12 weeks. Balance was measured via the Berg Balance Scale and Frailty and Injuries: Cooperative Studies of Intervention Techniques-4 Scale at baseline and week 6 and week 12. Participant compliance to the intervention was captured via paper logs and the electronic record collected by the Wii Fit Plus®. Results: Participants in the intervention group were 95% compliant based on electronic records. There were no significant differences between groups for total score on either balance scale. There was a significant group × time interaction in favor of the intervention for maximum velocity y (P < .05), average velocity (P < .05), and was trending for maximum velocity x (P = .05) in the tandem step, eyes closed position. Conclusions: The results suggest that the Wii Fit Plus® is appropriate for home-based interventions in middle-aged women. Modest improvements in balance indicate that this may be an effective means to improve or maintain balance in older women. More research is needed to determine compliance and benefits to reducing fall risk in durations exceeding 12 weeks.
Zachary S. Zeigler, Pamela D. Swan, Dharini M. Bhammar and Glenn A. Gaesser
The acute effect of low-intensity walking on blood pressure (BP) is unclear.
To determine if the acute use of a walking workstation reduces ambulatory blood pressure (ABP) in prehypertensive men and women.
Ten prehypertensive adults participated in a randomized, cross-over study that included a control workday and a walking workstation workday. ABP was measured for 7 hour during the workday and for 6 hour after work.
Both systolic BP (SBP) (134 ± 14 vs. 137 ± 16 mmHg; P = .027) and diastolic BP (DBP) (79 ± 10 vs. 82 ± 12 mmHg; P = .001) were lower on the walking workstation day. Postwork hours (4:00 PM–10:00 PM), SBP (129 ± 13 vs. 133 ± 14 mmHg; P = .008), and DBP (74 ± 11 vs. 78 ± 13 mmHg; P = .001) were also lower on the walking workstation day. DBP load was significantly lower during the walking workstation day, with only 14% of the readings above 90 mmHg compared with 22% of the control day readings (P = .037).
Accumulation of very-light-intensity physical activity (~2 METs) over the course of a single work day using a walking workstation may reduce BP burden in prehypertensive individuals.
Kelley K. Pettee Gabriel, Rebecca L. Rankin, Chong Lee, Mary E. Charlton, Pamela D. Swan and Barbara E. Ainsworth
The 400 m walk test has been used in older adults; however, the applicability in middle-aged populations is unknown.
Data were obtained from the Evaluation of Physical Activity Measures in Middle-Aged Women (PAW) Study and included 66 women (52.6 ± 5.4 years). Participants were instructed to walk at a brisk, maintainable pace; time taken to complete the 400 m was recorded in seconds. Intraclass correlation coefficients (ICC) were used to assess test-retest reliability. Spearman rank order correlation coefficients were used to examine the concurrent validity of the walk test with cardiorespiratory fitness and associations with physical activity, body composition, flexibility, static balance, and muscular fitness, adjusted for age and body mass index.
Participants completed the walk at visits 4 and 5 in 248.0 and 245.0 seconds, respectively. The walk test had excellent reproducibility [ICC = 0.95 (95% CI: 0.92, 0.97)] and was significantly associated with estimated (ρ = −0.43; P < 0.0001) and measured (ρ = −0.56; P < 0.001) VO2max. The walk test was also significantly related to physical activity, body composition, flexibility, and balance.
These findings support the utility of the 400 m walk test to estimate cardiorespiratory fitness and reflect free-living physical activity in healthy, middle-aged women.