Background: Physical fitness (PF) is an expression of the physiological functioning of multiple body components. PF is an important prognostic factor in terms of cardiovascular mortality, cancer mortality, and all-cause mortality. PF has been related to some biomarkers in the general population but not in breast cancer survivors (BCS). Purpose: To evaluate the effects of PF on biomarkers potentially related to physical activity (PA) in a sample of BCS. Methods: Cross-sectional study. A total of 84 BCS (mean age 54) who had finished their treatment were recruited. Different components of PF were evaluated, namely body composition (anthropometry), cardiorespiratory fitness (one-mile walk test), muscular (handgrip and sit-to-stand timed test), and motor (gait speed) components. Sexual hormones, inflammation, and insulin resistance biomarkers were measured. Results: C-Reactive Protein (CRP) was associated with every component of physical fitness: cardiorespiratory fitness (p-value = 0.002), muscular (sit-to-stand timed test, p-value = 0.002) and motor (gait speed, p-value = 0.004) components, and body composition (body mass index, p-value = 0.003; waist, p-value < 0.000; and waist-to-hip index, p-value = 0.012). CRP also was associated with “poor physical condition,” a constructed variable that encompasses all components of physical fitness (p-value < 0.001). Insulin was associated with cardiorespiratory fitness and gait speed (p-values = 0.002 and 0.024, respectively). Insulin-like Growth Factor-1 was negatively associated with waist perimeter and waist-to-hip ratio. Conclusion: CRP can also be considered an indicator of poor PF in BCS. Implications for cancer survivors: in case of elevation of CRP indicating cardiovascular risk, health professionals should recommend lifestyle changes to improve BCS physical condition.

Background: The “effort character” (EC) is a resistance training method without reaching muscle failure. It was defined by González-Badillo and Gorostiaga Ayestarán (2002) as the relationship between the repetitions performed and the repetitions achievable. Then, the EC is at its maximum (i.e., 100%) when the subject realizes all the repetitions possible in a series with any load. Therefore, an EC of 50% indicates execution of 50% of the repetitions achievable in a series. This study aimed to determine the effects of two programs of eight weeks of concurrent training (CT) with different EC over muscle strength (MS), cardiorespiratory fitness (CRF), functional mobility (FM), health-related quality of life (HRQoL), and lipid profile (LP) among hospital workers. Methods: Fourteen hospital workers (age: 41.1 ± 10.8 years; body mass: 63.0 ± 10.8 kg; height: 165.2 ± 6.5 cm; body mass index (BMI): 23.0 ± 3.4 kg/m2) were randomly assigned to an EC 50% (n = 7) or EC 100% (n = 7) group. Results: The main finding was that both groups significantly improved in MS and FM levels but not HRQoL, with no statistical differences between EC 50% and EC 100% in adherence and any test despite performing half the volume of the strength workout. Conclusions: An eight-week CT program with different EC (i.e., EC 50% vs. EC 100%) seems to improve the MS and FM levels in hospital workers similarly. These findings could be very useful in health-training practices because of the possibility of planning training loads with half the volume of strength workouts without the loss of any training adaptation.