The concept that participation in exercise/physical activity reduces the risk for a host of chronic diseases is undisputed. Along with adaptations to habitual activity, each bout of exercise induces beneficial changes that last for a finite period of time, requiring subsequent exercise bouts to sustain the benefits. In this respect, exercise/physical activity is similar to other “medications” and the idea of “Exercise as Medicine” is becoming embedded in the popular lexicon. Like other medications, exercise has an optimal dose and frequency of application specific to each health outcome, as well as interactions with food and other medications. Using the prevention of type-2 diabetes as an exemplar, the application of exercise/physical activity as a medication for metabolic “rehabilitation” is considered in these terms. Some recommendations that are specific to diabetes prevention emerge, showing the process by which exercise can be prescribed to achieve health goals tailored to individual disease prevention outcomes.
Barry Braun, Nancy I. Williams, Carol Ewing Garber, and Matthew Hickey
As the discipline of kinesiology ponders what should compose a kinesiology curriculum, it is worth considering the broad context. What is our responsibility to imbue students with values, viewpoint, and a vocabulary that facilitates their success in a context greater than our discipline? How do we decide what those things are (e.g., professional integrity, analytical thinking, cultural understanding, social responsibility, problem solving, leadership and engaged citizenship, effective communication, working collaboratively, preparation for lifelong learning)? How do we create a curriculum that provides sufficient understanding of disciplinary knowledge and critically important foundational skills? The purpose of this paper is to provide a jumping-off point for deeper discussion of what our students need most and how we can deliver it.
Joseph Hamill, Patty S. Freedson, Priscilla M. Clarkson, and Barry Braun
This study involved an 8-day protocol to determine the effects of delayed-onset muscle soreness (DOMS) on the mechanics of the lower extremity and on oxygen consumption during level running. On Day 1 the subjects, 10 healthy female recreational runners, were administered a treadmill max V̇O2 test. They completed a 30-min downhill run on Day 3 to induce muscle soreness. On Days 2, 5, and 8 they completed a 15-min level run at a speed corresponding to 80% of V̇O2max. Subsequent to each run the subjects completed a muscle soreness questionnaire and a blood sample was taken for creatine kinase (CK) analysis. Data analysis revealed statistically significant between-day differences for perceived muscle soreness and CK activity. However, metabolic cost was not different between days. There were significant differences between days in maximum ankle support dorsiflexion and plantar flexion and maximum knee flexion during both support and swing. None of the global parameters describing the total stride produced significant differences between Days 2 and 5. Therefore DOMS appeared to have little effect on V̇O2 and a small effect on the kinematics of the lower extremity.
Sarah Kozey-Keadle, John Staudenmayer, Amanda Libertine, Marianna Mavilia, Kate Lyden, Barry Braun, and Patty Freedson
Individuals may compensate for exercise training by modifying nonexercise behavior (ie, increase sedentary time (ST) and decrease nonexercise physical activity [NEPA]).
To compare ST and NEPA during a 12-week exercise training and/or lifestyle intervention.
Fifty-seven overweight/obese participants (19 M/39 F) completed the study (mean ± SD; age 43.6 ± 9.9 y, BMI 35.1 ± 4.6 kg/m2). There were no between-group differences in activity levels at baseline. Four-arm quasi-experimental intervention study 1) EX: exercise 5 days per week at a moderate intensity (40% to 65% VO2peak) 2) rST: reduce ST and increase NEPA, 3) EX-rST: combination of EX and rST and 4) CON: maintain habitual behavior.
For the EX group, ST did not decrease significantly (mean ((95% confidence interval) 0.48 (–2.2 to 3.1)% and there was no changes in NEPA at week-12 compared with baseline. The changes were variable, with approximately 50% of participants increasing ST and decreasing NEPA. The rST group decreased ST (–4.8 (0.8 to 7.9)% and increased NEPA. EX-rST significantly decreased ST (–5.1 (–2.2 to 7.9)% and increased time in NEPA at week-12 compared with baseline. The control group increased ST by 4.3 (0.8 to 7.9)%.
Changes in nonexercise ST and NEPA are variable among participants in an exercise-training program, with nearly half decreasing NEPA compared with baseline. Interventions targeting multiple behaviors (ST and NEPA) may effectively reduce compensation and increase daily activity.
Lisa Chasan-Taber, Marushka Silveira, Bess H. Marcus, Barry Braun, Edward Stanek, and Glenn Markenson
Physical activity during pregnancy is associated with reduced risk of adverse maternal and fetal outcomes. However, the majority of pregnant women are inactive and interventions designed to increase exercise during pregnancy are sparse. We evaluated the feasibility and preliminary efficacy of an exercise intervention among a diverse sample of pregnant women.
The B.A.B.Y. (Behaviors Affecting Baby and You) Study is conducted at a large tertiary care facility in Western Massachusetts. We randomized 110 prenatal care patients (60% Hispanic) to an individually tailored 12-week exercise intervention arm (n = 58) or to a health and wellness control arm (n = 52) at mean = 11.9 weeks gestation. Physical activity was assessed via the Pregnancy Physical Activity Questionnaire (PPAQ).
After the 12-week intervention, the exercise arm experienced a smaller decrease (−1.0 MET-hrs/wk) in total activity vs. the control arm (−10.0 MET-hrs/wk; P = .03), and a higher increase in sports/exercise (0.9 MET-hrs/wk) vs. the control arm (−0.01 MET-hrs/wk; P = .02). Intervention participants (95%) reported being satisfied with the amount of information received and 86% reported finding the study materials interesting and useful.
Findings support the feasibility and preliminary efficacy of a tailored exercise intervention in increasing exercise in a diverse sample of pregnant women.
Rebecca E. Hasson, Kirsten E. Granados, David Xavier Marquez, Gary Bennett, Patty Freedson, and Barry Braun
Racial differences in psychological determinants of exercise exist between non-Hispanic blacks (blacks) and non-Hispanic whites (whites). To date, no study has examined racial differences in the psychological responses during and after exercise. The objective of this study was to compare psychological outcomes of single exercise bouts in blacks and whites.
On 3 separate occasions, sedentary black (n = 16) and white (n = 14) participants walked on a treadmill at 75%max HR for 75 minutes. Questionnaires assessing mood, state anxiety, and exercise task self-efficacy were administered before and after each exercise bout. In-task mood and rating of perceived exertion (RPE) were measured every 5 minutes during exercise.
Exercise self-efficacy and psychological distress significantly improved in both blacks and whites. However during exercise blacks reported more positive in-task mood and lower RPE compared with whites.
These data suggest that racial differences exist in psychological responses during exercise. Further research should confirm these findings in a larger, free-living population.
Barry Braun, Priscilla M. Clarkson, Patty S. Freedson, and Randall L. Kohl
The effects of dietary supplementation with Coenzyme Q10 (CoQlO), a reputed performance enhancer and antioxidant, on physiological and biochemical parameters were examined. Ten male bicycle racers performed graded cycle ergometry both before and after being given 100 mg per day CoQlO or placebo for 8 weeks. Analysis of variance showed a significant difference between groups for postsupplementation serum CoQ10. Although both groups demonstrated training related improvements in all physiological parameters over the course of the study, there were no significant differences between the two groups (p>.05). Both groups showed a 21 % increase in serum MDA (an index of lipid peroxidation) after the presupplementation exercise test. After 8 weeks this increase was only 5 % , and again was identical for both groups. Supplementation with CoQlO has no measurable effect on cycling performance,
Steven K. Malin, Brooke R. Stephens, Carrie G. Sharoff, Todd A. Hagobian, Stuart R. Chipkin, and Barry Braun
Exercise and metformin may prevent or delay Type 2 diabetes by, in part, raising the capacity for fat oxidation. Whether the addition of metformin has additive effects on fat oxidation during and after exercise is unknown. Therefore, the purpose of this study was to evaluate the effect of metformin on substrate oxidation during and after exercise. Using a double-blind, counter-balanced crossover design, substrate oxidation was assessed by indirect calorimetry in 15 individuals taking metformin (2,000 mg/d) and placebo for 8–10 d. Measurements were made during cycle exercise at 5 submaximal cycle workloads, starting at 30% peak work (Wpeak) and increasing by 10% every 8 min to 70% Wpeak. Substrate oxidation was also measured for 50 min postexercise. Differences between conditions were assessed using analysis of variance with repeated measures, and values are reported as M ± SE. During exercise, fat oxidation (0.19 ± 0.03 vs. 0.15 ± 0.01 g/min, p < .01) and percentage of energy from fat (32% ± 3% vs. 28% ± 3%, p < .01) were higher with metformin than with placebo. Postexercise, metformin slightly lowered fat oxidation (0.12 ± 0.02 to 0.10 ± 0.02 g/min, p < .01) compared with placebo. There was an inverse relationship between postexercise fat oxidation and the rate of fat oxidation during exercise (r = –.68, p < .05). In healthy individuals, metformin has opposing actions on fat oxidation during and after exercise. Whether the same effects are evident in insulin-resistant individuals remains to be determined.