Sarcopenia, the age-related decline in muscle mass and function, derives from multiple etiological mechanisms. Accumulative research suggests that reactive oxygen species (ROS) generation plays a critical role in the development of this pathophysiological disorder. In this communication, we review the various signaling pathways that control muscle metabolic and functional integrity such as protein turnover, cell death and regeneration, inflammation, organismic damage, and metabolic functions. Although no single pathway can be identified as the most crucial factor that causes sarcopenia, age-associated dysregulation of redox signaling appears to underlie many deteriorations at physiological, subcellular, and molecular levels. Furthermore, discord of mitochondrial homeostasis with aging affects most observed problems and requires our attention. The search for the primary suspect of the fundamental mechanism for sarcopenia will likely take more intense research for the secret of this health hazard to the elderly to be unlocked.

Taekwondo is a combat sport with intermittent characteristics.The combat has short periods of high intensity interspersed by low-intensity activity displacements and pauses. During most of a training session, there is a high variation of heart rate (HR) values which could make it unfeasible to monitor the training load.However, there are no studies regarding the reproducibility of HR as a parameter of training intensity. PURPOSE: To evaluate the agreement of HR responses in two identical taekwondo training sessions that occurred in the same week. METHODS: Nine athletes wore cardiac monitors (Polar H7) and were submitted to two identical sessions (S1 and S2), consisting of five blocks: 1) Warm-up; 2) Sparring Drills A; 3) Sparring Drills B; 4) Combat Simulation; 5) Stretching. The HR was monitored continuously using Polar Team software. We analyzed mean HR (HRmean) and peak HR (HRpeak) in absolute (bpm) and relative to the maximum (%HRmax). ANOVA, Lin's correlation (L), and Bland-Altman concordance analysis were performed. RESULTS: There were no significant differences to HRmean (S1 = 68%; S2 = 63% of HRmax; p=0.62) and HRpeak (S1 = 82%; S2 = 83%; p=0.55) between sessions. Very strong correlation values were found between sessions for HRmean and HRpeak in absolute (L =0.89 and L =0.91) and relative (L = 0.91 and L = 0.91) values, respectively. Combat simulation (Block 4 = 196±7.52 bpm) showed higher HR values than all others. Regarding Bland Altman results, we found a very small difference of -3.1± 4.3 bpm in HRmean and 1.3±3.0 bpm in HRpeak between S1 and S2. CONCLUSIONS: There were no differences between training sessions for HRmean and HRmax, high agreement and correlation for all variables. HR during simulated combat block were higher than others. Polar Team software and H7 belts show reproducible values in Taekwondo training sessions.

Female dancers had generally higher estimated VO2max when compared to ACSM classifications for healthy adults. We only had 30 males across our cohorts, warranting inclusion of more males to develop robust norms in male collegiate dancers. Our collegiate dancers participated primarily in modern/contemporary dance. Still, other styles of dance exist and more work is needed across genres and levels. Prior findings in collegiate dancers found aerobic fitness did not significantly change over the collegiate-academic career, the normative values we found in the current study can be used as baseline aerobic fitness norms in healthy collegiate dancers.

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