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Gross efficiency (GE) and the index of pedal force effectiveness (IFE) are important factors that enhance cyclists' performance; however, the effects of changing pedal force (gear ratio) and cadence on these indices while riding on a road racing bicycle are poorly investigated. This study aimed to examine the effect of changing gear ratio or cadence on GE and IFE using a road racing bicycle. Nine male cyclists completed graded submaximal cycling tests (five stages of 4 min submaximal cycling sessions with 1 min passive rest intervals). The work rate of each stage was determined using two principles: changing gear ratio at a fixed cadence and changing cadence at a fixed gear ratio. We determined GE and IFE using respiratory variables and pedal reaction forces, respectively. Increasing the gear ratio improved GE, and was associated with the IFE. Although increasing the cadence slightly improved GE from the initial level, the increased values then mostly maintained. IFE was almost stable even when cadence increased. Moreover, no significant correlation was observed between the changes in GE and IFE accompanied by increasing cadence. Our data indicate that an increasing gear ratio, but not cadence, may affect GE and IFE while riding on a road racing bicycle. [ABSTRACT FROM AUTHOR]

The Activities-specific Balance Confidence (ABC) scale has been widely used as patient-reported outcome measures for community stroke rehabilitation and its short version is beginning to be used. This study aimed to assess the psychometric properties of the short version of the ABC scale-Japanese (Short ABC-J). Eighty-four participants with chronic stroke (mean age was 66.4 ± 9.7 years, mean time post stroke was 4.7 ± 3.5 years) including 66 test-retest samples were analyzed. The Short ABC-J was assessed with the ABC-J, the Falls Efficacy Scale-International (FES-I), the Berg Balance Scale (BBS), and the Timed Up and Go Test (TUG-T). The internal consistency was good (Cronbach's alpha 0.90), reproducibility was excellent [intra-class correlation coefficient (ICC2,1) 0.92], and levels of absolute reliability were acceptable (standard error of measurement and minimal detectable change 8.32 and 23.07, respectively). Concurrent, convergent, and discriminative validity were supported for the FES-I, ABC-J, BBS, and TUG-T (all |rho| > 0.60, p <.001), and identifying balance and mobility (the area under the curve estimates ≥ 0.80) and discriminative power of the Short ABC-J were better than those of the FES-I and equal to or better than those of ABC-J. The Short ABC-J has good psychometric properties and is a valid and reliable measure of balance self-efficacy in Japanese community-dwelling people with chronic stroke. Further replication studies as well as other psychometric studies are needed. [ABSTRACT FROM AUTHOR]

We tested the hypothesis that there are sex differences in hindlimb unloading-induced activation of the forkhead box subfamily O3a (FoxO3a) signaling pathway in rat soleus muscle. Age-matched male and female Wistar rats were subjected to hindlimb unloading, and the soleus muscle was removed before or 1 or 7 days after unloading. Female rats showed greater percent changes in relative soleus muscle weight than males. FoxO3a phosphorylation was lower in females than in males and was associated with higher levels of protein ubiquitination 7 days after unloading. Heat shock protein 72 (Hsp72) levels were lower in female rats and increased in males during unloading. Female rats showed slightly higher myostatin levels, which showed a non-significant decline in male rats following unloading. Thus, males and females show different responses to the FoxO3a/ubiquitin-proteasome pathway following hindlimb unloading in rat soleus muscle, which may be associated with differences in Hsp72 expression and myostatin signaling. Keywords: Sex difference, Soleus muscle, Forkhead box O, Heat shock protein 72, Myostatin, Hindlimb unloading, Author(s): Toshinori Yoshihara[sup.1], Toshiharu Natsume[sup.1], Takamasa Tsuzuki[sup.1,2], Shuo-wen Chang[sup.1], Ryo Kakigi[sup.3], Takao Sugiura[sup.4] and Hisashi Naito[sup.1] Introduction Males and females exhibit marked physiological differences, including body composition [1], hormone concentration [...]

Background: There are several studies on the relationship between low back pain and physical activity. However, the results of these studies vary, and the relationship between them remains unclear. Therefore, we conducted a cross-sectional study to evaluate the association between objectively measured physical activity and low back pain in Japanese men. Methods: The study included 4022 Japanese men [average age: 47 (10) y]. Daily amount of moderate to vigorous physical activity and step counts were measured using an accelerometer. Low back pain, drinking and smoking, and lifestyle-related diseases were surveyed using a self-administered questionnaire. A logistic regression model was used to evaluate the relationship between physical activity and step counts with persistent low back pain after adjusting for confounders. Results: Persistent low back pain was reported in 428 participants. The multivariable-adjusted odds ratios of presenting persistent low back pain across quartiles of amount of moderate to vigorous physical activity were 1.00 (reference); 0.93 (95% confidence interval, 0.70-1.22); 0.97 (95% confidence interval, 0.74-1.28); and 0.67 (95% confidence interval, 0.50-0.90); P for linearity = .012. Conclusion: We found a significant inverse relationship between objectively measured physical activity and persistent low back pain. [ABSTRACT FROM AUTHOR]