In this study, we tested the hypotheses that unaccustomed eccentric exercise (ECC) would reduce the elastic modulus and dynamic stiffness of the upper trapezius muscle and that these changes would correlate with increases in muscle thickness, reflecting muscle edema. Shear wave elastography was used to measure elastic modulus, dynamic stiffness was assessed using myotonometry, and muscle thickness was measured using ultrasonography. All measurements were performed at four locations over the upper trapezius before and 24 h after a single bout of ECC. Fourteen healthy participants (11 males and 3 females; 23.2 ± 3.0 years; height 175.1 ± 10.4 cm; body mass 73.8 ± 11.3 kg) took part in the study. Overall, ECC resulted in decreased elastic modulus (from 45.8 ± 1.6 to 39.4 ± 1.2 kPa, p < 0.01) and dynamic muscle stiffness (from 369.0 ± 7.3 to 302.6 ± 6.0 N/m, p < 0.01). Additionally, ECC resulted in increased muscle thickness (from 6.9 ± 0.4 to 7.3 ± 0.4 mm, p < 0.01). Spatial changes (across the four locations) were found for elastic modulus, stiffness and thickness. No significant correlations were found between changes in measures of muscle stiffness, or between changes in stiffness and changes in thickness. In conclusion, the present pilot study showed that ECC altered biomechanical muscle properties, reflected by decreased elastic modulus and dynamic muscle stiffness 24 h after ECC.

Linear skeletal growth was reduced with increased blood lead, even at levels below that considered for action by US CDC standards. The reduction in height occurred primarily in leg length. Arm length was also reduced, suggesting limb lengths in general were affected by blood lead. Results are consistent with lead-associated interruption of (1) major epiphyseal growth plate chondrocyte hyperplasia, hypertrophy, and interrupted matrix calcification as a primary cause of stunted long bone growth, and reduced stature; and (2) attenuated osteoblast activity (proliferation and migration) as a secondary cause of stunted growth in the study population.

Sex Differences in Growth and Performance of Track and Field Athletes 11-15 Years Objective: To evaluate sex differences in functional performances of youth track and field athletes. Methods: Four tests of functional capacity were administered to 309 youth 11-15 years training for track and field at sport schools, 136 boys and 173 girls. Grip strength, standing long jump, 2 kg medicine ball throw and 20 m sprint were measured; height, weight and adiposity were also. Two age groups were compared, 11-13 and 14-15 years. ANCOVA was used to test sex differences by age group in the total sample (disciplines combined) and specific disciplines; age, height and weight were covariates. Results: For the total sample, males in both age groups performed better than females in the four tests but sex differences were greater among 14-15 year olds. Within disciplines, sex differences among sprinters and middle distance and distance runners were greater at 14-15 years. Results varied for general athletics; the magnitude of sex differences was similar for strength in both age groups, greater for the throw at 11-13 years and greater for the jump and sprint at 14-15 years. Conclusion: Although sex differences in performance were apparent among athletes 11-13 years, they were greater among athletes 14-15 years, reflecting to a large extent the male adolescent spurt in body size, muscle mass, strength and power. Sex differences were more established in sprinters and middle distance and distance runners, and more variable in participants in general athletics.

Background It’s really important to measure the actual functional physical fitness of elderly independent living persons from different environments to know the level and rate of decrease may inform about the threat of loss of functional independence, hence the need to monitor and assess the senior’s motor realm and adapt to it the appropriate programs and treatments in the care for the elderly person. Methods The study involved 5367 people (mean age 69,63 ± 7,06), including 4164 women (mean age 69,55 ± 7,11) and 1203 men (mean age 69,91 ± 6,86) aged 60 to 93 years old. We have measured basic anthropometric features and physical fitness (by using Senior Fitness Test). Results The average values in individual SFT tests significantly decrease along with age. After age of 80 and 85 there were no sex differences in SFT. The largest deficits concern the dynamic balance and the decrease reaches 69% in men and 62% in women A significantly higher rate of decline in aerobic capacity concerns men (43%) than women (36.9%). A clearly lower rate of loss occurs in the muscular strength of the lower and upper body and does not exceed 30%. Conclusions The results are of great clinical importance for the development of effective prevention and gerontological education programs in terms of promoting active lifestyle and successful ageing, at the same time limiting the economic consequences of treatment and hospitalisation.

Humans exhibit sex differences in competitiveness, sensation seeking and risk-taking attitude, which are required in sports. These attributes are often linked to prenatal testosterone (PT) exposure. The second-to-fourth digit length ratio (2D:4D) is an indicator of PT exposure. A lower 2D:4D indicates higher PT exposure and vice versa. Males generally have a lower 2D:4D than females. Sensation- and/or thrill-seeking behaviours have also been found to be negatively associated with 2D:4D. Boxing and judo are considered to be high-risk sports. Voluntary participation in judo/boxing in contrast to aerobics can be guided by such behaviours and thus have an association with lower 2D:4D. This cross-sectional study included 167 female students from a military academy in Wrocław, Poland. Of them, 119 had voluntarily chosen aerobic exercise, and 48 opted for judo/boxing. Height, weight and second and fourth digit lengths were measured. Physical fitness was assessed using Eurofit tests. The two groups showed similar physical fitness and body size. However, the judo/boxing group had significantly lower mean 2D:4D values than the aerobics group. It is proposed that voluntary choice of participation in a sport discipline by women could be linked to the 'organizational' effect of intrauterine testosterone exposure during prenatal growth.