9 age and sexrelated differences9章的年龄和性别差异课件

Age- and Sex- Related Differences Chapter 9 Objectives Evaluate safety when lifting with children Discuss sex-related differences in muscular function Describe the effects of aging on muscle Explain why adaptations vary Sex vs. Gender Sex = is biologically founded. A female has 2X chromosomes while a male has 1X and 1Y chromosome Gender = the behavioral, cultural, or psychological traits typically associated with one sex Terminology Chronological age- age in years and months (60 month diff) Biological age- stages of development measured by skeletal age, sex characteristics, physique Measured in Tanner stages Youth Resistance Training Children have not yet reached puberty Adolescents are post puberty Children increase strength with resistance training Most strength gains in preadolescents are neural Youth Resistance Training Adolescents may increase strength due to hypertrophy Female adolescents have limited testosterone, but growth hormone and IGF cause muscle development (hypertrophy) WHY? Benefits of Youth Resistance Training Prevent injury Improve motor skills Improve sports performance Maximize bone density Improve strength and power Potential Risks Potential for injury to epiphyseal plate, typically with heavy overhead lifts in an unsupervised setting Risk of repetitive use injuries Risk of catastrophic injury when basic safety guidelines are not followed Program Design for Children Address all fitness goals Children should be mature and have the desire to train Provide high quality instruction Program Design for Children Progress gradually and safely Focus on form and technique Consider beginning new exercises with a stick instead of a bar Guidelines for Youth Resistance Training Teach the child the benefits of training Provide competent supervision Provide a safe training environment Guidelines for Youth Resistance Training In general, perform 3 sets of 6-15 reps of single and multi- joint exercises For advanced multi-joint exercises, use appropriate form and loads Guidelines for Youth Resistance Training Use 2-3 nonconsecutive training days Use adult spotters when appropriate Vary the training program throughout the year Encourage children to drink water during exercise Female Athletes Body composition- generally more fat, less muscle and bone No difference prior to puberty After puberty, increased fat deposits Shorter time period for bone growth Strength and Power in Females Absolute measures- men have more muscle mass, more strength Relative to body mass- lower body strength similar to males, upper body is less Relative to muscle cross-sectional area- very small differences exist between males and females The “quality” of muscle tissue in males and females is almost the same Resistance Training in Females Because the quality of muscle tissue is similar as in males, responses to RT are similar Absolute strength gains are less than in men Relative strength gains are equal or greater than in men Hypertrophy in females does occur and is similar to males per unit of muscle cross sectional area Program Design for Females No appreciable differences than in males where the goals of training are the same Resistances will be lower Should pay particular attention to Upper body strength in sports requiring extensive use of the upper body Anatomical areas of high injury risk in females Older Adults Performance decreases with age Weightlifters- decrease 1-1.5% from age 30 through 70, more rapidly thereafter Trainability- older adults will improve with a training program at any age Age-related Musculoskeletal Changes Osteopenia- loss of bone mass Sarcopenia- loss of muscle mass mostly in type II fibers Decreased power output, likely due to the decrease in type II fibers and neural changes WHY? Resistance Training in Elderly Increases are possible in all areas of development- strength, power, bone mass, muscle mass, functionality, endurance Low intensity training = modest improvement in fitness variables Program Design in the Elderly Resistance training of equal or more importance than aerobic training to delay age-related changes in the elderly Walking Stairclimbing Dressing Standing from chair/bed Resistance Training Guidelines for Elderly Screen all participants for medical complications Warm-up prior to all activity Use appropriate resistance Resistance Training Guidelines for