To investigate central and peripheral fatigue induced by a typical session of electromyostimulation (EMS) of the triceps surae muscle. A series of neuromuscular tests including voluntary and electrically evoked contractions were performed before and immediately after 13 min of EMS (75 Hz) in 10 healthy individuals. Maximal voluntary contraction torque of the plantar flexor muscles significantly decreased (-9.4%; P < 0.001) after EMS, and this was accompanied by an impairment of central activation, as attested by twitch interpolation results (P < 0.05), whereas soleus maximal Hoffmann reflex and tibialis anterior coactivation did not change significantly. Contractile properties associated with paired stimuli and maximal M-wave amplitude for both soleus and medial gastrocnemius muscles (-9.4 and -38.7%, respectively) were significantly affected by EMS (P < 0.05), whereas postactivation potentiation did not change. A single bout of EMS resulted in fatigue attributable to both central and peripheral factors. The most obvious alteration in the function of the central nervous system is a decrease in the quantity of the neural drive to muscle from the supraspinal centers. On the other hand, neuromuscular propagation failure was more evident for the muscle with the higher percentage of Type II fibers.

A science review by Delago (2014) suggested that the distance-traveled feature on Fitbit® was an accurate measurement. However, as speed increased the accuracy of the Fitbit® decreased, meaning the faster the pace, the greater the error for distance measured. Whereas a systematic review conducted by Evenson et al. (2015) reported only one study that measured the distance-traveled feature. This study concluded that the Fitbit® over-estimated at lower speeds and underestimated at faster speeds. PURPOSE: To examine whether the fitness device, Fitbit® Charge, provides an accurate measurement of the distance-traveled feature at various speeds and to expand on the research regarding the distance-traveled feature. METHODS: Twenty-eight healthy students from a Division III college participated in this study. A repeated measure ANVOA experimental design compared the Fitbit® distance-traveled output under three dependent variable speeds of 2.5mph (76.1m/min), 4.5mph (120.7m/min), and 6mph (160.9m/min) to a Quinton MedTrack ST55 treadmill distance-traveled measurement. All participants completed a six-minute trial for each of three different speeds on a treadmill while wearing the Fitbit® Charge. Following each six-minute trial, the distance-traveled was compared between the treadmill and the Fitbit® output. A repeated measure ANOVA analysis was used to test for significant differences (p < .05) among the three speeds between the Fitbit® and the treadmill. RESULTS: Results did not detect significant differences in distance-traveled between the Fitbit® Charge compared to the treadmill at 2.5mph (F(1,27) = 0.67, p = .42), 4.5mph (F(1,27) = 2.45, p = .13), or 6mph (F(1,24) = .66, p = .43) speeds. CONCULSION: It seems reasonable to conclude that the distance-traveled feature on the Fitbit® Charge is valid when compared to treadmill output at these three speeds. Future research could look at a wider range of speeds to ensure further accuracy. IRB# 1516-0099

PURPOSE: Cardiovascular disease (CVD) is rapidly becoming the predominant cause of mortality in early stage breast cancer survivors. The magnitude of this problem is likely to increase with the aging US population, improvements in breast cancer-specific survival, and the continued use of adjuvant therapies with cardiovascular toxicities. Thus, novel strategies are required to predict and mitigate excess CVD risk in breast cancer survivors. METHODS: The MD Anderson Healthy Heart Program was created to improve cardiorespiratory fitness (CRF) and reduce existing cardiovascular risk factors in cancer survivors. Patients undergo a one-time consultation with a cardiologist to discuss previous cancer treatment and CVD risk factor modification after measurement of CVD risk factors (e.g. LDL cholesterol, blood pressure). A cardiopulmonary exercise test (CPET), using a TrueOne 2400 metabolic cart (Parvo Medics Inc, Sandy, UT), is then administered by an exercise physiology technologist (EPT) in concert with the cardiologist to assess CRF (Vo2peak). For the current results, we included only women with a history of early stage breast cancer examined between January 2016 and September 2016. RESULTS: A total of 47 women with a history of early stage breast cancer had a mean age of 60 ± 8 years and a mean BMI of 27.6 ± 6.5 kg/m2. The mean Vo2peak was 20.9 ± 4.1 mL·kg-1 · min-1, the equivalent of 29.6% below healthy, sedentary women. Mean time from breast cancer diagnosis to Healthy Heart consult was 8 ± 6 years. CONCLUSION: There is a significant and sustained loss of CRF in early breast cancer patients presenting to the MD Healthy Heart Program. Given these findings, a personalized exercise prescription developed by the EPT as part of the Healthy Heart Program is provided to increase exercise adherence. Ultimately, the goal of the program is to utilize exercise as a non-pharmacologic strategy to mitigate cardiac insult and promote improvement in CRF to maintain healthy hearts throughout the cancer continuum.

The degree to which temperature affects endurance performance and exercise metabolism in trained athletes is not fully known. PURPOSE: In the present study, we investigated the impact of cold and neutral environmental temperatures on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and whole-body substrate oxidation during submaximal steady-state cycling in trained cyclists. Additionally, we assessed subsequent time trial (TT) performance. METHODS: Ten trained male cyclists (age = 22.80 ± 2.76 yr; height = 178.58 ± 5.65 cm; mass = 74.02 ± 10.95 kg; body fat = 18.35 ± 3.37%; peak oxygen consumption (VO2peak) = 60.60 ± 4.67 ml·kg-1·min-1; power output in Watts (W) at lactate threshold (LT) = 234.00 ± 35.00 W) participated in a randomized, crossover designed study that consisted of baseline testing to determine LT and VO2peak, two familiarization trials, and two experimental trials. The experimental trials consisted of 25 min of cycling at 70% LT, followed immediately by 25 min at 90% LT in either cold (3.06±1.78°C; 41.63±5.60%RH) or thermoneutral (19.43±0.98°C; 38.97±2.23%RH) conditions. Following a 15-min break, subjects then completed a 20kmthermoneutral room. SCAAT interstitial glycerol concentrations were measured in situ throughout the trial via the microdialysis technique. Two-way (group x time) repeated measures analysis of variance tests and student t-tests (where appropriate) were used to identify differences between measured variables with significance set at p ≤ 0.05. RESULTS: A significant time effect was observed for HR (p < 0.001), core temperature (p < 0.001), interstitial glycerol (p < 0.001), blood lactate (p < 0.028), carbohydrate oxidation (p < 0.0001), fat oxidation (p < 0.0001), and VO2 (p < 0.001). No significant differences were observed between conditions for any measured variable including TT performance (cold, 189.9±24.6 v. neutral, 187.5±27.4 W, p=0.858). CONCLUSION: SCAAT lipolysis increases during steady state exercise. However, metabolism and performance are not impacted by cold ambient conditions. This study was funded by the National Strength and Conditioning Association and Florida State University.

Physical activity is highly beneficial in patients with type 1 diabetes (T1D). The American Diabetes Association recommends at least 150min/week of moderate intensity aerobic physical activity, defined as 50–70% of maximum heart rate (HRmax); however, exercise intensity prescribed as percentages of HRmax leads to inhomogeneous cardio-respiratory acute responses when dealing with individuals with T1D where chronic stress may affect ß1-receptor sensitivity. PURPOSE: To determine the exercise intensity given as percentages of HRmax in T1D patients versus healthy controls (nT1D) related to the degree and direction of the HR performance curve (HRPC). METHODS: Eight male T1D patients (25±5 yrs, BMI: 24±2 kg/m2, HbA1c: 7.3±0.6%, duration of diabetes: 15±9 yrs) and eight male nT1D (26±5 yrs, BMI: 23±2 kg/m2) performed an incremental exercise test (IET) until exhaustion (start 40 W; increase 20 W/min). nT1D were matched for age and maximum power output (Pmax), respectively. The first and the second lactate turn points (LTP1/LTP2), as well as the direction and degree of the time course of HRPC (kHR), were determined form IET and compared to 50% and 70% of HRmax. kHR, power output (P) and HR at LTP1 were compared between groups in relation to 50% and 70% of HRmax. Group differences were calculated by an ANOVA with post-hoc testing, p≤0.05. RESULTS: No significant differences were found between both groups for HRmax and Pmax (p>0.05). HR at LTP1 vs. 50%HRmax and 70%HRmax were significantly different for both groups, except for the nT1D group at 70%HRmax. P at 50%HRmax was significantly lower than at LTP1 in both groups; at 70%HRmax P was significantly higher only in T1D (p<0.05). Significant differences for P between both groups were only found at 70%HRmax (133±17 W vs. 91±38 W, p<0.05). 50%HRmax was as low as resting conditions (0 W) in 38% of the T1D group and 50% of the nT1D. kHR was lower in T1D (0.21±0.30 vs. 0.39±0.27) but the difference was not statistically significant (p>0.05). CONCLUSION: 50%HRmax is clearly too low to induce any training effects even when exercising 150min/week. A lower kHR for the acute HR response in T1D patients indicates a reduced ß1-receptor sensitivity, which needs to be respected for the calculation of target exercise intensities.

PURPOSE: Social participation provides health benefits for older adults, but it is not known whether social participation is associated with their being more physically active or less sedentary. We examined these associations in a population-based sample of older Japanese adults.\nMETHODS: A mail survey conducted in 2010 and gathered data from 1146 community-dwelling, non-working older adults (mean age: 70.1 years, 43% men) on social participation, physical activity, sedentary time and socio-demographic characteristics. Median splits were used to categorize social participation, physical activity and sedentary behavior as either ‘higher’ or ‘lower’. Multivariate logistic regression analyses were used to calculate odds ratios (ORs) for the associations of higher versus lower social participation with being physical active and having higher sedentary time. Similar analyses were conducted after classifying sedentary behaviors into two distinct types: passive sedentary behaviors (consisting of “television viewing”, “sitting around”, and “listening or talking while sitting”) and mentally-active sedentary behaviors (consisting of “computer use” and “reading books or newspapers”)\nRESULTS: Those with higher social participation had a significantly greater odds of higher physically activity (OR=2.10, [95% confidence interval (CI): 1.44-3.06] among men; OR=1.93, [1.39-2.68] among women); and, a significantly lower odds of higher sedentary time among men (OR=0.62, [0.42-0.90]), but not among women (OR=0.80, [0.58-1.11]). Those with higher social participation had significantly lower passive sedentary time (OR=0.55, [0.38-0.81] for men; OR=0.72 [0.51-0.99] for women), but this was not the case for mentally-active sedentary time (OR=1.36, [0.91-2.02] for men; OR=1.17 [0.83-1.63] for women).\nCONCLUSIONS: Promoting social participation among older adults may be effective for increasing their physical activity and reducing sedentary time.

Increased physical activity has been shown to improve classroom behavior in children. No study has examined the relationship between classroom level behavior and school day physical activity in disadvantaged children from low-income schools. PURPOSE: The purpose of this study was to examine the cross-sectional relationship between classroom level on-task behavior and average school day physical activity throughout one school week. METHODS: A total of 106 classrooms were recruited from five low-income schools from a school district located in the Mountain West Region of the U.S. Classrooms were recruited from the 1st through 6th grades and class sizes ranged from 16 to 28 students. On-task classroom behavior was assessed at the beginning of the 2015-2016 academic school year using momentary time sampling methods for an observation duration time of 15-minutes. Classrooms were stratified into those that achieved 80% on-task behavior and those that did not. Physical activity was assessed at the student level using Yamax pedometers and Actigraph accelerometers that were worn for the entire school day for one school week. Step counts and time in MVPA were averaged at the classroom level to account for clustering of observations within classrooms. A multivariate analysis of variance (MANOVA) test was used to examine the relationship between a categorical classroom behavior variable and classroom-level physical activity. RESULTS: Classrooms that achieved at least 80% classroom behavior displayed higher school day step counts (Δ= 449 steps, p < 0.001, Cohen’s d = 0.26) and time in MVPA (Δ= 3.6 minutes, p < 0.001, Cohen’s d = 0.28) compared to classrooms that displayed lower classroom behavior. CONCLUSION: Classrooms that display higher levels of on-task behavior tend to record higher levels of average school day physical activity. The results provide further evidence of the relationships between favorable classroom behavior and physical activity. Future research needs to examine this relationship for potential causation and bi-directionality so that effective interventions can be employed.

Parkinson patients are at a high risk of falling due to the neurological disorder. Standing balance is an important indicator of postural control capacity among people with falling risks. During standing, respiratory activity, as the internal perturbation, may alter the motion of center of gravity. Therefore, in Parkinson patients, different respiratory activities could influence balance outcomes related to Center of Pressure (COP). PURPOSE: this study was to examine the effects of different breathing patterns on balance performance in patients with Parkinson. METHODS: ten Parkinson patient (PG) and ten age-matched health individuals (CG) were recruited. Each participant randomly performed 3 trials of balance test under three respiratory conditions (neutral, thoracic, and abdominal breathing patterns) with eyes closed. 95% sway area (A95% in cm2), average velocity (VAverage in cm/s) and standard deviation at ML (SDML) and AP (SDAP) directions were recorded for each trial. Two-way MANOVA was performed to examine the effects of group and respiratory activity on the association among COP-related measures listed above. Post Hoc Tuekey’s test was applied when necessary. RESULTS: Significant differences were observed between groups on all measures (P <.05). Compared to control group, Parkinson group exhibited greater A95% (PG:10.36 ± 9.89 cm2, CG: 7.52 ± 7.07 cm2), higher VAverage (PG: 3.18 ± 1.24 cm/s, CG: 2.56 ± .92 cm/s), more SDML (PG: .58 ± .30, CG: .54 ± .28) and SDAP (PG: .84 ± .31, CG: .68 ± .24). No other significant difference was observed. CONCLUSIONS: Parkinson’s group showed a worse balance performance as expected. However, the effect of respiration on traditional COP related measures was not observed. This may because that traditional measures could not detect the alteration of COP induced by the internal perturbation of respiratory activity. Instead of using traditional measures, future studies should adopt the nonlinear dynamic analysis to assess the complexity of COP motion potentially altered by respiratory activity.