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Purpose: To determine whether differential kinematics, kinetics, rates of energy use, and cardiopulmonary responses occur during running with water bottles and bottle belt holders compared with running only. Methods: Trained runners (N = 42; age 27.2 [6.4] y) ran on an instrumented treadmill for 4 conditions in a randomized order: control run (CON), handheld full water bottle (FULL; 16.9 fluid oz; 454 g), handheld half-full water bottle (HALF; 8.4 fluid oz; 227 g), and waist-worn bottle belt holder (BELT; hydration belt; 676 g). Gas exchange was measured using a portable gas analyzer. Kinetic and kinematic responses were determined by standard 3-dimensional videographic techniques. Interactions of limb side (right and left) by study condition (CON, FULL, HALF, and BELT) were tested for rates of oxygen use and energy expenditure and kinematic and kinetic parameters. Results: No significant limb-side × condition interactions existed for rates of oxygen use or energy expenditure. A significant interaction occurred with sagittal elbow flexion (P P Conclusions: Carrying water by hand or on the waist does not significantly change the kinematics of running motion, rates of oxygen use and energy expenditure, or cardiopulmonary measures over short durations. Runners likely make adjustments to joint moments and powers that preserve balance and protect the lower-extremity joints while maintaining rates of oxygen use and energy expenditure.

BACKGROUND:Cardiorespiratory fitness (CRF) is the only major risk factor that is not routinely assessed in the clinical setting, for preventive medicine. A valid and practical CRF test is needed for use in the clinics. The objective of this study is to demonstrate the validity of a 3-minute squat test to assess CRF in primary care. METHODS:A cross-sectional study in which the participants performed both the Ruffier squat test and the Balke maximal treadmill test. The study was conducted in a clinical setting from September 2016 to March 2017. We recruited a convenient sample of 40 adults between 18 and 64 years from the general U.S. population. Participants completed 30 squats in 45 seconds, paced by a metronome. Heart rate was measured at rest (P1), immediately after the test (P2), one minute after the test (P3). [Formula: see text] was measured using the Balke maximal treadmill fitness test. RESULTS:Of the 40 participants, there were 18 men and 22 women. Mean age was 31.2 years (SD = 9.9). We found that the best [Formula: see text] predictors were HR features P1/height and (P2-P3)/age3. Our best-performing model using these two features predicted individuals' CRF levels with an adjusted R2 of 0.637, sensitivity of 0.79, and specificity of 0.56. CONCLUSIONS:The study provided strong evidence for the validity of the squat test in the clinical setting. Further, the equation of our model along with [Formula: see text] normative tables provides an efficient and easy way to assess CRF in a primary care setting.

Background: Regular physical activity can not only help with weight management, but also lower cardiovascular risks, cancer rates, and chronic disease burden. Yet, only approximately 20% of Americans currently meet the physical activity guidelines recommended by the US Department of Health and Human Services. With the rapid development of mobile technologies, mobile apps have the potential to improve participation rates in exercise programs, particularly if they are evidence-based and are of sufficient content quality. Objective: The goal of this study was to develop and test an instrument, which was designed to score the content quality of exercise program apps with respect to the exercise guidelines set forth by the American College of Sports Medicine (ACSM). Methods: We conducted two focus groups (N=14) to elicit input for developing a preliminary 27-item scoring instruments based on the ACSM exercise prescription guidelines. Three reviewers who were no sports medicine experts independently scored 28 exercise program apps using the instrument. Inter- and intra-rater reliability was assessed among the 3 reviewers. An expert reviewer, a Fellow of the ACSM, also scored the 28 apps to create criterion scores. Criterion validity was assessed by comparing nonexpert reviewers’ scores to the criterion scores. Results: Overall, inter- and intra-rater reliability was high with most coefficients being greater than .7. Inter-rater reliability coefficients ranged from .59 to .99, and intra-rater reliability coefficients ranged from .47 to 1.00. All reliability coefficients were statistically significant. Criterion validity was found to be excellent, with the weighted kappa statistics ranging from .67 to .99, indicating a substantial agreement between the scores of expert and nonexpert reviewers. Finally, all apps scored poorly against the ACSM exercise prescription guidelines. None of the apps received a score greater than 35, out of a possible maximal score of 70. Conclusions: We have developed and presented valid and reliable scoring instruments for exercise program apps. Our instrument may be useful for consumers and health care providers who are looking for apps that provide safe, progressive general exercise programs for health and fitness. [J Med Internet Res 2017;19(3):e67]