Stiffness In Males Research Articles

Participation in physical activity and arterial stiffness in males with autism spectrum disorder

Selective eating and hyperphagia are frequently encountered in individuals with autism spectrum disorder (ASD). They may increase arterial stiffness, a risk factor for cardiovascular disease, via excessive sodium intake, nutritional deficiency, and obesity. Therefore, primary prevention of cardiovascular disease is an important issue in this population. To test our hypothesis that greater levels of physical activity are associated with lower levels of arterial stiffness in individuals with ASD as well as those without ASD, this study compared brachial-ankle pulse wave velocity (baPWV) in active males with and without ASD and less active males without ASD. We recruited subjects with ASD via organizations providing opportunities to play sports. Subjects without ASD were subdivided into less and more active groups based on scores from the International Physical Activity Questionnaire. Daily physical activity levels were higher in the more active control (2992 ± 681 MET min/week) and ASD (2992 ± 972 MET min/week) groups than in the less active control group (337 ± 86 MET min/week). BaPWV was lower in the more active control (10.7 ± 0.3 m/s) and ASD (9.9 ± 0.6 m/s) groups than in the less active control group (11.7 ± 0.3 m/s). There were no differences in physical activity level and baPWV between more active males with ASD and those without ASD. These results suggest that physically active males with ASD also have elastic central arteries. We would like to propose that participation in physical activities may be beneficial as a primary cardiovascular disease prevention strategy for not only for males without ASD but also those with ASD.

Medial Tibiofemoral-Joint Stiffness in Males and Females Across the Lifespan.

Context : Analyzing ligament stiffness between males and females at 3 maturational stages across the lifespan may provide insight into whether changes in ligament behavior with aging may contribute to joint laxity. Objective : To compare the stiffness of the medial structures of the tibiofemoral joint and the medial collateral ligament to determine if there are differences at 3 distinct ages and between the sexes. Design : Cross-sectional study. Setting : Laboratory. Patients or Other Participants : A total of 108 healthy and physically active volunteers with no previous knee surgery, no knee injury, and no use of exogenous hormones in the past 6 months participated. They were divided into 6 groups based on sex and age (8-10, 18-40, 50-75 years). Main Outcome Measure(s) : Ligament stiffness of the tibiofemoral joint was measured with an arthrometer in 0° and 20° of tibiofemoral-joint flexion. The slope values of the force-strain line that represents stiffness of the medial tibiofemoral joint at 0° and the medial collateral ligament at 20° of flexion were obtained. Results : When height and mass were controlled, we found a main effect (P < .001) for age group: the 8- to 10-year olds were less stiff than both the 18- to 40- and the 50- to 75-year-old groups. No effects of sex or tibiofemoral-joint position on stiffness measures were noted when height and mass were included as covariates. Conclusions : Prepubescent medial tibiofemoral-joint stiffness was less than postpubescent knee stiffness. Medial tibiofemoral-joint stiffness was related to height and mass after puberty in men and women.

Sex differences in relationship between passive ankle stiffness and leg stiffness during hopping

The goal of this study was to examine the hypothesis that the relationships between passive ankle stiffness and leg stiffness would be different between males and females. 10 males and 10 females performed hopping in place on two legs at three frequencies of 2.0, 2.5, and 3.0Hz. Based on a spring-mass model, leg stiffness, which is defined as the ratio of maximum ground reaction force to maximum center of mass displacement at the middle of the stance phase, was calculated using the vertical ground reaction force. Further, passive ankle stiffness was calculated as the slope of the passive ankle torque-angle relationship, which results from controlled passive ankle dorsiflexion. There was no significant difference in the leg stiffness between males and females at three hopping frequencies; however, females displayed less passive ankle stiffness than males. Further, significant positive linear relationships were found between the passive ankle stiffness and the leg stiffness for females at all hopping frequencies; however, there were no significant correlations between the passive ankle stiffness and the leg stiffness in males for all hopping frequencies. These results suggest that the relationship between the passive ankle stiffness and the leg stiffness are not the same between males and females, which may lead to a greater risk of anterior cruciate ligament injuries in females.

THE RELATIONSHIP BETWEEN CHRONIC OCCUPATIONAL STRESS AND ARTERIAL STIFFNESS: A CROSS-SECTIONAL STUDY IN CHINESE WORKERS

Objectivesexposure to occupational stress increases the risk of cardiovascular disease. However, few reports focused on the association between occupational stress and arterial stiffness as a suitable marker of early stage...

Comparison of triceps surae structural stiffness and material modulus across sex

Dynamic joint stability is derived, in part, from active muscle stiffness. Previous research has identified greater structural musculotendinous stiffness in males than in females, suggesting potential sex differences in joint stability. However, structural stiffness is influenced by anthropometrics, and it is currently unclear if sex differences in musculotendinous stiffness are purely functions of anthropometrics or related to additional factors. The purpose of this investigation was to compare structural stiffness and material modulus of the triceps surae between sexes to determine the relative influence of anthropometrics. It was hypothesized that males would demonstrate greater structural stiffness and material modulus. Twenty male and 20 female individuals volunteered for participation. Active triceps surae structural stiffness was estimated from the damped frequency of oscillation of the shank about the ankle. Material modulus was calculated as the ratio of stress to strain, derived from estimates of triceps surae length and physiological cross-sectional area. Structural stiffness was significantly greater in males [mean (SD)] [137.41 (26.99) N/cm] than females [91.06 (20.10) N/cm]. Similarly, material modulus was significantly greater in males [2778.51 (549.95) Pa] than females [1968.58 (439.61) Pa]. Greater structural stiffness in males identified in previous literature appears to be a true phenomenon. Identification of greater material modulus in males suggests that these differences are likely attributable to sex differences in tendon stiffness and muscle architecture. These results indicate that male musculature is more effective at resisting changes in its length, a finding which may have implications for joint stability.