PURPOSE: This study was conducted to examine androgenicity of the progestin in oral contraceptive pills and its effect on maximal leg strength in females. METHODS: Twelve participants who were using a monophasic pill containing 30 microg ethinylestradiol plus either 150 microg levonorgestrel (LEV) or 250 microg norgestimate (NOR) for at ...

This study investigated gender differences in upper-body contribution to cycle muscle power in 23 adolescents. All subjects performed two 5-s and one 20-s cycling sprint, using two protocols: with handgrip (WG) and without handgrip (WOG). Maximal handgrip strength was assessed for each individual. Absolute peak and mean cycling power was ...

BACKGROUND: The advent of highly crosslinked polyethylene has allowed the re-evaluation of the use of femoral heads larger than 32 mm for metal-on-polyethylene total hip arthroplasties. However, the effect of larger heads on the frictional torque of highly crosslinked polyethylene is unknown. METHODS: We performed an in vitro examination of ...

BACKGROUND: The loss of muscle mass is considered to be a major determinant of strength loss in aging. However, large-scale longitudinal studies examining the association between the loss of mass and strength in older adults are lacking. METHODS: Three-year changes in muscle mass and strength were determined in 1880 older ...

Decreased steadiness of muscle force may be associated with ageing and could be a cause of falls in older people. We studied this in isometric and anisometric quadriceps contractions in healthy young and older people. The older group contained people with and without a history of medically unexplained falls. Forty-four ...

We evaluated whether quadriceps and hamstrings weakness depended on chronicity in amateur athletes with anterior cruciate ligament deficiencies. We hypothesized that the weakness would not recover to the level of healthy control subjects without structured rehabilitation. Secondarily, we asked whether quadriceps and hamstrings side-to-side percent asymmetry in strength was consistent ...

BACKGROUND: In certain occupations, including farm work, workers are exposed to hazardous substances, some of which are known to be toxic to the nervous system and may adversely affect muscle strength. Measurement of hand-grip strength may be useful for detecting neurotoxic exposure. METHODS: The authors studied 3522 participants of the ...

A major feature of aging is a reduction in muscle strength from sarcopenia, the loss of muscle mass. Sarcopenia impairs physical ability, reduces quality of life and increases the risk of fall and injury. Since aging is a process of stochastic decline, there may be many factors that impinge on ...

This report describes three males from a single kinship, ages 7, 8, and 67 years with clinically asymptomatic dystrophinopathy. The index case was an 8-year-old male evaluated for asymptomatic but persistently elevated serum creatine kinase levels. Muscle biopsy demonstrated a mild myopathy, without necrotic fibers. Immunostaining for dystrophin revealed a ...

REASONS OF PERFORMING STUDY: To obtain broader insight into the muscle of foals with different genetic background, muscle fibre composition, its post natal development and citrate synthase (CS) activity of the gluteus medius were investigated. Because muscle properties are influenced genetically and related directly to performace ability, muscle characteristics should ...

PURPOSE: To measure the hand grip strength of Malaysians aged 18 to 65 years. METHODS: Between January and April 2003, 412 subjects (200 women and 212 men) were recruited from staff, students, and visitors of the University of Malaya Medical Centre. Socioeconomic, general health, and lifestyle data were collected from ...

The grip strength of 214 independently ambulatory Chinese older adults (M age = 75.1 +/- 7.0 yr.) was measured, and preliminary mean values presented. Their previous occupations were recorded, and the physical demands of those occupations in terms of oxygen consumption and work done were classified. Grip strength generally decreased ...

The effects of creatine and creatine plus beta-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus beta-alanine (CA) group. During each testing ...

The aim of this study was to evaluate the maximum bite force in temporomandibular disorders (TMD) patients. Two hundred women were equally divided into four groups: myogenic TMD, articular TMD, mixed TMD and control. The maximum bite force was measured in the first molar area, on both sides, in two ...

OBJECTIVE: To evaluate the possible effects of sex and age on strength-duration time constant (SDTC). METHODS: The SDTC of 126 healthy volunteers was measured following stimulation of right median nerve at the wrist. Variations in values were evaluated according to sex and age. RESULTS: The SDTC was 438.6+/-114.5 micros in ...

Electrical impedance myography (EIM) is a painless and non-invasive technique for the assessment of muscle which we apply here to the effects of normal aging. The paper presents a cross-sectional analysis of EIM data from the quadriceps and tibialis anterior of 100 healthy subjects (44 men, 56 women, ages 18-90 ...

OBJECTIVE: This study assessed the utility and construct validity of a new patient global assessment of symptom change for hand osteoarthritis (OA) by examining its associations with change over time in grip strength, pinch strength, and AUStralian CANadian Osteoarthritis Hand Index (AUSCAN). METHODS: Participants (N=531, 80% female, mean age=68) were ...

STUDY DESIGN: Cross-sectional descriptive study. OBJECTIVES: To determine the maximal isometric strength of the flexor, extensor, and rotator muscles of the cervical spine in healthy females of working age to document reference values for diagnostic and rehabilitation purposes. BACKGROUND: Reference values for the isometric strength of the cervical muscles have ...

BACKGROUND: Handgrip strength is an important predictor of disability and mortality among old people. The aim was to compare the grip strength among very old people in three regions of Europe. METHODS: In this substudy of the European Challenge for Healthy Aging project, only the long-lived probands were included. The ...

Several studies have reported predictors for loss of mobility and impairments of physical performance among frail elderly people. To evaluate the relationship between lifetime occupation and physical function in persons aged 80 years or older. Data are from baseline evaluation of 364 subjects enrolled in the ilSIRENTE study (a prospective ...

PURPOSE: This study was designed to compare mechanomyography (MMG) and the force relationship during isometric ramp contractions of biceps brachii muscles in females and males to identify sex differences in the MMG responses. METHODS: Subjects (10 females and 9 males; age range, 20-26 yr) were asked to exert an isometric ...

OBJECTIVE: To assess the relation between knee muscle strength, gait performance, and perceived participation in subjects with chronic mild to moderate poststroke hemiparesis. DESIGN: Descriptive analysis of convenience sample. SETTING: University hospital. PARTICIPANTS: Fifty men and women (mean age, 58+/-6.4y) 6 to 46 months poststroke. INTERVENTIONS: Not applicable. MAIN OUTCOME ...

Context: Stretching is common among athletes as a potential method for injury prevention. Stretching-induced changes in the muscle spindle properties are a suggested mechanism, which may imply reduced proprioception after stretching; however, little is known of this association. Objective: To evaluate whether acute stretching of the shoulder muscles affects position ...

The reduced physiological capacity evident with ageing may affect the ability to perform many tasks, potentially affecting quality of life. Previous research has clearly demonstrated the reduced capacity of the respiratory system with ageing and described the effect that habitual physical activity has upon this decline. This research aimed to ...

This study aimed at examining the effects of joint angle and age on the maximal voluntary contraction (MVC) torque, for the agonist and antagonist muscle groups around the ankle, i.e., the dorsi- and plantar-flexors. To this aim, neural and muscular factors were investigated in two groups of healthy men: 11 ...

INTRODUCTION: Reliable and sensitive muscle strength/power assessments are essential when evaluating age-related and/or training-induced changes in maximal strength and power. AIM: To investigate the reproducibility and inter-relationship of single-joint isokinetic/isometric leg muscle strength vs multi-joint mechanical muscle function during counter-movement jump (CMJ) in moderately trained aging individuals (age 72.3+/-6.6). RESULTS: ...

BACKGROUND AND PURPOSE: Following spinal cord injury (SCI), paralyzed muscles undergo physiological changes that alter their force responses to electrical stimulation. The purpose of this study was to investigate the effects of SCI on the contractile properties and force-frequency relationship (FFR) of the paralyzed human quadriceps femoris muscle of adolescents ...

OBJECTIVE: To assess changes in physical capacity and its determinants in persons with a spinal cord injury. DESIGN: Prospective cohort study. Measurements at the start of active rehabilitation (t1), 3 months later (t2), at discharge (t3), and 1 year after discharge (t4). SETTING: Eight rehabilitation centers in The Netherlands. PARTICIPANTS: ...

OBJECTIVES AND DESIGN: The use of the radial pulse as a diagnostic tool is an important part of the Chinese medicine (CM) clinical evaluation. This study reports the findings of an investigation into inter-arm pulse strength differences in subjects and the relationship to traditional pulse claims relating to gender. METHOD: ...

BACKGROUND: Diabetes mellitus (DM) is a potential contributor to the muscle abnormalities and poor physical functioning of the dialysis population. METHODS: Thirty-three dialysis patients without DM (non-DM group) were compared with 25 dialysis patients with DM (DM group). Measures were made of cross-sectional area and composition of the leg muscles ...

OBJECTIVE: The aim of this study is to assess a possible relationship between unilateral hip dysplasia and sternocleidomastoid muscle function during a fatiguing task. METHODS: In this patient-control, cross-sectional study, 11 female patients (aged 37-63 years) with unilateral coxoarthrosis subsequent to hip dysplasia and 9 female control subjects matched for ...

PURPOSE: We examined the relationship of DO and aging, and bladder function in female volunteers. MATERIALS AND METHODS: We recruited 85 cognitively competent, fully functional female volunteers who were 22 to 90 years old (median age 54) with and without symptoms suggestive of DO. Comprehensive assessment included a bladder diary, ...

The aims of this study were to examine age and sex differences in elbow extensor and flexor anatomical muscle cross-sectional area (mCSA) measured by magnetic resonance imaging (MRI) and the location of maximal mCSA as a percentage of the distance from the distal to the proximal end of the humerus. ...

It is important to establish valid field measures of lower body strength in the elderly, and to provide representative normative values that are culturally specific in order to help health professionals in the risk assessment of this group. A sample of 1,038 elderly Hong Kong Chinese undertook a 30-sec chair ...

INTRODUCTION/PURPOSE: Muscles of the trunk, hip, and knee influence the orientation of the lower extremity during weight bearing activities. The purpose of this study was threefold: first, to compare the orientation of the lower extremity during a single leg (SL) squat among male and female athletes; second, to compare the ...

The psychosocial inventory of ego strengths (PIES) was devised as a measure of Erikson's eight ego strengths. The present investigation extended previous research through examination of the validity and reliability of the PIES among 502 high school students. The study also included an appraisal of Erikson's ego strengths as indices ...

The bilateral limb deficit (BLD) describes the difference in maximal or near maximal force generating capacity of muscles when they are contracted alone or in combination with the contralateral muscles. A deficit occurs when the summed unilateral force is greater than the bilateral force. This study examined the presence of ...

The aim of this study was to investigate whether personality strengths during adolescence are associated with decreased risk of developing psychiatric disorders, educational or occupational problems, violent or criminal behaviors, and interpersonal difficulties during early adulthood. A representative community sample of 688 mothers from upstate New York and their offspring ...

BACKGROUND AND AIMS: The most common cause of accidental injury and death in people over age 65 results from impacts associated with falling. Balance impaired older adults have poorer balance control than healthy young adults or healthy older adults. Lack of sufficient lower extremity strength and inability to rapidly produce ...

We studied the movement of center of gravity (CG) in young and aged subjects during maximum grip of right or left hand. Body-sway was recorded with stabilometry in rest-stand position and in maximum grip. The data from right-or left-handed young subjects were analyzed. Maximum grip power was not different between ...

The performance in a mirror star tracing task was assessed in two groups of volunteers (yoga and control) with 26 people in each group, and age range between 18 and 45 years. The star to be traced was six pointed and the outline was made up of 60 circles (4 ...

The purpose of this investigation was to examine the relationship between strength and the magnitude and time sequential structure of force variability. Young and old adults produced isometric force via index finger abduction to a visually presented target corresponding to a constant force level of 5 or 25% maximal voluntary ...

OBJECTIVE: To gather initial data on the Wolf Motor Function Test (WMFT) from able-bodied participants. DESIGN: Cross-sectional cohort study. SETTING: Clinical research laboratory. PARTICIPANTS: A convenience sample of 51 healthy able-bodied, right-hand dominant, adult participants, between the ages of 40 and 79 years. INTERVENTION: One-time administration of the WMFT. MAIN ...

The aim of the study was to identify motor structures in elite female volleyball players aged 14-17, and to assess the effect of these motor structures on their technical and situation efficiency. For this purpose, a battery of 12 motor tests as predictor variables, and a set of six technical ...

PURPOSE: The purpose is to study the age trajectory of hand-grip strength after the age of 45 years. METHODS: In this study, we use data from three large nationwide population-based surveys of Danes aged 45 to 102 years with a total of 8342 participants with grip-strength measurements and up to ...

The purpose of this study was to examine the effects of aging and endurance running on the mechanical and morphological properties of different muscle-tendon units (MTUs) in vivo. The investigation was conducted on 30 elderly and 19 young adult males. For the analysis of possible MTU adaptation in response to ...

OBJECTIVES: To assess differences in neuromuscular dynamic restraint between high-skilled and low-skilled prepubescent girls and boys. To determine the contribution of sport experience and physical characteristics to motor skill. SUBJECTS: Nineteen girls and 17 boys (8.89-9.40 y) participated. INTERVENTION: Isometric hamstring and quadriceps muscle strength was assessed. Subjects performed 3 ...

BACKGROUND: The decline of motor performance of the human hand-arm system with age is well-documented. While dominant hand performance is superior to that of the non-dominant hand in young individuals, little is known of possible age-related changes in hand dominance. We investigated age-related alterations of hand dominance in 20 to ...

Comparison of protein intakes on strength, body composition and hormonal changes were examined in 23 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were stratified into three groups depending upon their daily consumption of protein; below recommended levels (BL; 1.0 - 1.4 g.kg-1.day-1; n = 8), ...

Quadriceps strength and mass peak in the third decade of life, plateau, and then decline from the fifth decade on. To examine the influence of chronic endurance training and age on lean mass and leg strength, women runners (n = 62, age 43-69 years) and sedentary participants (n = 33, ...