Isometric strength of the upper extremities in Czech men older than 18 years

The aim of this study was to compare isometric strength of the upper extremities in a sample of men from the Czech republic (n=638). Only the dominant upper limb was tested. The examined subjects were 18 years old or older. The measured values (in kilograms) were obtained via hand-held dynamometry testing (a digital hand-held dynamometer). The results of the hand-held dynamometry testing were compared across six age categories (18-29, 30-39, 40-49.... 70+ years). It was found that isometric strength of the dominant upper limb in men increases up to the age group 30-39 years and then declines. The highest average value (55.6 kg) was found in the age group 30-39 years, and expectably, the lowest values (34.4 kg) were documented in the age category 70+ years. The largest decline in isometric strength (-8.8 kg) was found between the age groups 60-69 years and 70+ years.

Effects of follicular versus luteal phase-based strength training in young women

Hormonal variations during the menstrual cycle (MC) may influence trainability of strength. We investigated the effects of a follicular phase-based strength training (FT) on muscle strength, muscle volume and microscopic parameters, comparing it to a luteal phase-based training (LT). Eumenorrheic women without oral contraception (OC) (N = 20, age: 25.9 ± 4.5 yr, height: 164.2 ± 5.5 cm, weight: 60.6 ± 7.8 kg) completed strength training on a leg press for three MC, and 9 of them participated in muscle biopsies. One leg had eight training sessions in the follicular phases (FP) and only two sessions in the luteal phases (LP) for follicular phase-based training (FT), while the other leg had eight training sessions in LP and only two sessions in FP for luteal phase-based training (LT). Estradiol (E2), progesterone (P4), total testosterone (T), free testosterone (free T) and DHEA-s were analysed once during FP (around day 11) and once during LP (around day 25). Maximum isometric force (Fmax), muscle diameter (Mdm), muscle fibre composition (No), fibre diameter (Fdm) and cell nuclei-to-fibre ratio (N/F) were analysed before and after the training intervention. T and free T were higher in FP compared to LP prior to the training intervention (P < 0.05). The increase in Fmax after FT was higher compared to LT (P <0.05). FT also showed a higher increase in Mdm than LT (P < 0.05). Moreover, we found significant increases in Fdm of fibre type ΙΙ and in N/F only after FT; however, there was no significant difference from LT. With regard to change in fibre composition, no differences were observed between FT and LT. FT showed a higher gain in muscle strength and muscle diameter than LT. As a result, we recommend that eumenorrheic females without OC should base the periodization of their strength training on their individual MC.