Week 7 H&L PDF

Muscle mass Muscle strength Muscle power Muscle endurance The size/Weight of skeletal muscle Muscle mass increases similarly in boys and girls until puberty Atrophy in muscle mass when aging -- 40% reduction in muscle cross sectional area from 20-80yr/old - Loss in fibres - Reduction in...

Muscle mass Muscle strength Muscle power Muscle endurance The size/Weight of skeletal muscle Muscle mass increases similarly in boys and girls until puberty Atrophy in muscle mass when aging -- 40% reduction in muscle cross sectional area from 20-80yr/old - Loss in fibres - Reduction in size of fibres Muscles ability to generate force Strength increases linearly with age until puberty -- then accelerated development - Grip strength for boys increases 400% from 7 to 17 years old - Muscle strength peaks in 20-30s - Women's maximal strength is about 63.5% of mens strength 12-14% DECLINE IN STRENGTH PER DECADE AFTER 50 Rate at which muscle perform work -- The ability to exert force quickly 30-years secular changes in jumping performance -- 11% Difference between 11 year old's in 1985 -- 2015 in long jump -- OBESITY? Fast twitch -- Type 2 -- 100m - Muscle fibres decrease in size with age Slow Twitch -- Type 1 -- Marathon - Muscle size is not affected by age Muscles ability to continue to perform successive exertions or maintain an isometric contraction Flexed arm hang - Muscular endurance improves with age and is diverse between male and females Females are able to Perform a greater number of repetitions than males at 50%,60% and 70% of **1RM** - There is a decline in muscular endurance as with age +-----------------------------------+-----------------------------------+ | Flexibility | Balance | +===================================+===================================+ | Sit and reach | Children have a lower centre of | | | mass making balance easier | | Peak flexibility is achieved in | | | the late teens or early 20's | - Adolescent growth spurt often | | | accompted by a loss of | | - Aging results in a decreased | coordination | | flexibility and ROM | | | | - Big changes in body size, | | Causes | brain needs to recalibrate | | | | | - Muscles and tendons lose | Poor balance frequently reported | | elasticity | within older adults | | | | | - Synovial fluid becomes less | Sensory moto, and cognitive | | Viscous | changes alter biomechanics | | | | | - Osteoarthritis | - Impaired reflex activities | | | | | - Decline in physical activity | - Posture changes | +-----------------------------------+-----------------------------------+ Muscular systems in early life - Safety of resistance training in youth - Youth RT is low risk - Incidence of sports related injuries in 1 year - 0.7% = RT - 19% = football - 15% = basketball - 2% = soccer - 'STUNTS GROWTH' -- it does damage growth cartilage but doesn't stunt growth - Youth RT Guidelines - Qualified supervision + warmup/cool down - Begin RT 2-3 times per week on non-consecutive days Muscular strength - Well-designed RT program -- enhances muscular strength of children and adolescents - Strength gains un children related to neural mechanisms rather than hypertrophy Youth Resistance Training improved - Cardiovascular risk profile - Facilitate weight control - Strengthen bone - Enhance psychosocial well-being - Improve motor skills Resistance training for obese youth - Increase risk of musculoskeletal injuries - Obese youth typically enjoy RT if it is in short periods Muscular systems in later life - Sarcopenia -- condition characterised by progressive loss of skeletal muscle mass and strength - Appears to begin in the 70's -- similar between men and women Muscle strength - Hand grip strength measured -- predicts mortality RT and Muscle strength - Resistance training, 2 times per week for 12 weeks - Greater gains in muscular strength observed using heavy loads (80% 1RM) RT and functional capcity - 28% increase in stair walking speed - 12% increase in walking speed