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Purpose: The ability to perform motor imagery (MI) might be impaired by the physical fatigue elicited during training. Interestingly, there is also theoretical support for a more limited influence ...

Background There is limited knowledge regarding the potential benefits of physical activity in patients with metastatic breast cancer. Objective The Advanced stage Breast cancer and Lifestyle Exercise (ABLE) Trial aimed to assess the feasibility of a physical activity intervention in women with metastatic breast cancer and to explore the effects of physical activity on functional, psychological, and clinical parameters. Methods The ABLE Trial was a single-arm, 6-month intervention study with a home-based, unsupervised, and personalized walking program using an activity tracker. At baseline and 6 months, we assessed anthropometrics, functional fitness, physical activity level, sedentary behavior, quality of life, fatigue, and tumor progression. Paired proportions were compared using the McNemar test and changes of parameters during the intervention were analyzed using the Wilcoxon signed-rank test, the Mann-Whitney test, and Spearman rank correlations. Results Overall, 49 participants (mean age 55 years; recruitment rate 94%) were enrolled and 96% adhered to the exercise prescription (attrition rate 2%). Statistically significant improvements in the 6-minute walking distance test (+7%, P Conclusions The high recruitment and adherence rates suggest the willingness of patients with metastatic breast cancer to participate in a physical activity program. The beneficial outcomes regarding physical fitness and anthropometry of this unsupervised physical activity program may encourage these patients to maintain a physically active lifestyle. Future randomized controlled trials with larger sample sizes are warranted. Trial Registration ClinicalTrials.gov NCT03148886; https://clinicaltrials.gov/ct2/show/NCT03148886

Ultra-endurance mountain running has become extremely popular in recent years, and the energy cost is one of the factors that influence the final performance. The aim of this study was to determine if the energy cost of uphill running (uphill Cr) can be calculated from level Cr (Energy cost of running in mLO2.kg-1.mn-1) in a heterogeneous group of mountain ultra-endurance runners using the di Prampero equation, and if fatigue could change this relationship. Twenty-four male ultra-trail runners ran on a level and uphill (10%) treadmill at 60% of velocity at V O2max (velocity at V O2 max in m.s-1) before and after a mountain ultra-marathon (MUM). The mean performance on the MUM was 728 ± 117 minutes. Positive and strong correlations were found between level and uphill Cr pre-MUM (r = 0.84, P < 0.001) and post-MUM (r = 0.86, P < 0.001), in mLO2.kg-1.mn-1. This study demonstrated that level and uphill Crs are related in a heterogeneous group of mountain runners. However, the differences observed between theoretical and real uphill Crs (7.9 and 8.5% pre and post-MUM) demonstrated that an uphill Cr measurement is necessary to predict the performance of high level runners.

for a given cumulated work. Compared with KE0, KE240 generated a greater evoked torque loss (Db100: −24.3 ± 5.3% vs −5.9 ± 6.9%; P < 0.001), a higher O2 consumption (23.7 ± 6.4 mL/min/kg vs 15.7 ± 3.8 mL/min/ kg; P < 0.001), but a lower voluntary activation (VA) loss (−4.3 ± 1.6% vs −11.2 ± 4.9%; P < 0.001). The neuromuscular perturbations were intermediate for KE30 (Db100: −10.0 ± 6.8%; VA: −7.2 ± 2.8%). Although the amount of mechanical work cumulated strongly determined the magnitude of torque decrease, the contraction velocity and mode influenced the origin of the neuromuscular fatigue. The metabolic stress and peripheral fatigue increased but reduction of VA is attenuated when the contraction velocity increased from 0°/s to 240°/s.

Clemencon M, Hautier CA, Rahmani A, Cornu C, Bonnefoy M. Potential role of optimal velocity as a qualitative factor of physical functional performance in women aged 72 to 96 years. Objective To assess the relationship of maximal leg power and its corresponding determinants (eg, optimal velocity and optimal torque) measured during maximal voluntary knee extension to physical functional performance of older women. Design Descriptive. Setting Community retirement homes. Participants Women (N=39) aged 72 to 96 years. Interventions Not applicable. Main Outcome Measures Volunteers performed in sitting position maximal knee extensions on an Ergopower dynamometer to calculate maximal leg power, optimal velocity, and optimal torque. Three standardized tests were also performed to evaluate physical performance: walking speed over 6m, time taken to rise 5 times from a chair, and time to climb 6 stairs. Results On multiple regression analysis, leg power (mean, 1.37±0.80W/kg) significantly correlated with physical performance as measured by 6-m walking speed (mean, .85±.40m/s), chair-stand time (mean, 16.3±7.7s), and stair-climb time (mean, 7±4s), describing 16% to 33% of the variance. Optimal velocity (mean, 1.79±1.20 rad/s) also significantly correlated with 6-m walking speed, chair-stand time, and stair-climb time, describing 46% to 89% of the variance. Optimal torque (50.8±16.9Nm) did not correlate with physical performance. Conclusions Maximal power and moreover optimal velocity were thus found to be determinants of physical performance, both appearing as significant mobility factors in older adults. This may provide more focus on velocity-oriented training as a means of improving functional status.

Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (T(peak)) on the overall performance (i.e. mean torque, T(mean)) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240° · s(-1), beginning every 30 seconds. RTD, T(peak) and T(mean) as well as the Rate of EMG Rise (RER), peak EMG (EMG(peak)) and mean EMG (EMG(mean)) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (if(mean)) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eT(peak)) induced by high frequency doublet (100 Hz). T(mean) decrease was correlated to RTD and T(peak) decrease (R(²) = 0.62; p

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