Gender and Age Trends of the Coxsackievirus: A Retrospective Study of a Pediatric Practice

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The Effect of Seat Back Angle on Responses During Recumbent Cycling

The purpose of this study was to evaluate metabolic, cardiorespiratory, and perceptual responses during recumbent cycle ergometry performed at various seat back angles and different work rates. Healthy college-aged men performed steady-state exercise at two work rates, 100 watts (n=46) and 150 watts (n=26), using five back seat angles, 90, 105, 120, 135, and 150 degrees. The results of this study suggest that recumbent seat back angles of 135 to 150 degrees are associated with lower metabolic and cardiorespiratory stress during rest and submaximal exercise than more upright positions. The reduced stress at these angles is accompanied by lower perceptions of exertion and improved seating comfort. The failure of the base-line correction for resting V0 2 to remove the effect of seat back angle implies that the reduced physiological stress associated with these positions is due to reasons other than attenuated resting metabolic costs. It is concluded that the selection of recumbent seat back angles between 135 and 150 degrees can result in improved efficiency, reduced physiological stress, diminished perceptions of exertion, and increased seating comfort

Social, Environmental, and Racial/Ethnic Factors in Diabetes Prevalence in the U.S.

PURPOSE: The purpose of this study was to determine the extent to which socioeconomic status, race/ ethnicity, and disparities in neighborhood environmental factors affect diabetes prevalence among U.S. adults. METHODS: County-level data were collected from the 1000 U.S. counties with the highest diabetes incidence and the 1000 U.S. counties with the lowest diabetes incidence using the 2014 USDA Food Environmental Atlas. The dependent measure was diabetes prevalence. Independent measures were median household income, percentage of people with no car, percentage of population that was black, white, or Hispanic, and the number of fitness centers, fast food restaurants, farmer’s markets, and grocery stores. Stepwise multiple linear regression was used to assess the relationship of these independent variables to diabetes incidence. RESULTS: Of the nine independent measures evaluated, seven explained a significant amount of the variance in diabetes prevalence (Table 1). Median household income accounted for the largest proportion of variance (38%) with the non-white population percentages collectively accounting for an additional 19%. The specific indicators of commercial entities accounted for small (≤1%) but significant proportions of variance. CONCLUSION: The results of this study indicate socioeconomic and racial/ethnic factors account for the majority of variance in prevalence of diabetes in the U.S. However, not only availability but access to healthy foods and lifestyle choices also seem to play a role in the magnitude of the incidence of diabetes. There is an apparent need for local and federal programs to focus on these high-risk areas of concentrated poverty and minority populations in order to educate communities, increase social support, and improve access to factors related to developing healthy lifestyles

The Effects of Prior Caffeine Ingestion on Respiratory and Cardiovascular Responses During Submaximal Exercise in Trained and Untrained Women

Introduction: Caffeine consumption prior to exercise has been shown to produce beneficial effects during subsequent exercise in trained men. These benefits include decreased RPE, reduced respiratory exchange ratio (RER), and decreased oxygen deficit. While these effects have been demonstrated in men, little work has been done to evaluate the effects of prior caffeine ingestion on exercise responses in untrained women. Methods: Twelve women (6 trained, 6 untrained) completed two submaximal bouts of cycling, at 60% of maximal HR, 45 min after consuming either caffeine (3 mg/kg) or a placebo. During these bouts, RPE, RER, VO2, and HR were measured, and oxygen deficit was calculated post-exercise. Data were analyzed using a mixed model ANOVA with two independent groups, trained and untrained, and two caffeine conditions repeated across participants. Results: Caffeine was found to significantly decrease RER values during exercise (F(1,10)=22.62, p\u3c0.01) across groups with caffeine being responsible for about 69% (η2=0.69) of the change in RER. Although not significant, all participants reported lower RPE values during exercise after caffeine ingestion (F(1,10)=4.42, p=0.06), caffeine being responsible for about 31% (η2=0.306) of the change seen in RPE. Caffeine was not found to have a significant effect on VO2 (F(1,10)=2.00, p=0.19) or HR (F(1,10)=2.40, p=0.15) during exercise, or on measures of oxygen deficit (F(1,10)=0.48, p=0.51); however, the trained group did have a significantly higher oxygen deficit than the untrained group (F(1,10)=5.35, p=.04). There were no significant interactions between the caffeine treatment and group for any dependent variable. Conclusion: These results indicate that ingesting caffeine 45 min prior to exercise can lead to increased fat oxidation and lowered RPE without affecting VO2 or HR during submaximal exercise

Effects of Warm Up Intensity on Factors Related to Subsequent Performance of Submaximal Exercise

Introduction: Athletes often warm up (WU) prior to exercise to improve performance. However, there are no clear directives regarding the intensity of the WU that is most effective in improving physiological responses related to enhanced aerobic performance. Methods: Nine college-aged men (age, ht, mass, 20.6 yr, 1.7 m, 84.8 kg, respectively) performed WU of varying intensities, 60% ventilatory threshold (VT), 100%VT, and 120%VT prior to performing 5 min of steady state exercise at 80%VT on a cycle ergometer. O2 deficit, RPE, steady state heart rate (HRss), and steady state VO2 (VO2ss) were measured during the exercise bout. Results: There was a significant decrease in O2 deficit as WU intensity increased ((2,9)= 9.15, p = .002, 2=0.53) with the deficit being lowest after WU at 120%VT. RPE were significantly lower after WU at 120%VT than both 60% and 100%VT (=(2,9)=6.88, p=.007, 2=0.46). However, WU intensity did not significantly affect either HRss (F(2,9)=0.48, p=0.63) or VO2ss (F(2,9)=1.10, p=0.36) during the exercise bout. Conclusion: The findings suggest that a higher intensity WU improves factors related to improved aerobic performance, i.e. decreased O2 deficit and RPE, without adversely affecting factors that could lead to a decline in performance, i.e. increased HRss and VO2ss

Comparison of Hamstring and Quadriceps Muscle Activity in Men and Women Performing a Body Weight Squat

Multiple studies support the idea that women use a more quadriceps dominant activation pattern at the knee during stabilizing movements which may predispose them to a greater risk of ACL injury. A body weight squat is a common exercise used to strengthen knee musculature in attempt to minimize the risk of ACL injury. However, it is not clear whether this exercise activates the knee musculature in a manner that would not exacerbate the quadriceps dominance often observed in women. PURPOSE: To determine if women are more quadriceps dominant than men when performing a two-legged body weight squat. METHODS: Seven male and seven female Division III collegiate athletes (20.5±1.0 yrs, 176.2± 12.6 cm, and 79.7± 16.6 kg) provided informed consent and participated in this study. Surface EMG collected at 1000 Hz was used to measure the muscle activity of the vastus lateralis (VL) and the biceps femoris (BF), and normalized to the respective maximum voluntary isometric contraction (MVIC) for each muscle. Participants performed eight repetitions of a two-legged body weight squat at a cadence of 54 bpm. RMS EMG was computed across a 200 ms window and analyzed for the middle six repetitions at 15°, 45° and 60° of knee flexion during the movement. Hamstrings and quadriceps activity for the concentric phase of movement were evaluated separately, with two 2x3 (gender x joint position) mixed model ANOVAs. RESULTS: No interaction was observed between gender and joint position for either quadriceps (F(1,11) = 0.64, p = 0.54) or hamstring activity (F(1,11) = 1.24, p = .31). As knee flexion decreased, both quadriceps and hamstrings activity significantly decreased. Quadriceps activity, decreased from 41.7± 24.9%MVIC at 60° to 37.6± 21.7% at 45° to 34.2± 22.7% at 15° (F(1,11) = 5.74, p = 0.01). Likewise, hamstring activity decreased from 26.7± 28.9%MVIC at 60° to 20.6± 20.6% at 45° and to 18.2± 19.1% at 15° (F(1,11) = 3.92, p = 0.04). CONCLUSION: Gender-specific muscular imbalances do not occur during the performance of a bodyweight squat suggesting that such an exercise is appropriate as a part of strength training program designed to reduce ACL risk in women. However, knee angle is a relevant factor to consider when examining muscular characteristics of dynamic movements and injury mechanisms