Chapter 6: Muscles at Work PDF

CHAPTER 6 Muscles At Work Kinesiology Books Publisher 1 TABLE OF CONTENTS Types of Muscle Action Static Action Dynamic Action Factors Influencing Muscle Action Joint Angle Muscle Cross-...

CHAPTER 6 Muscles At Work Kinesiology Books Publisher 1 TABLE OF CONTENTS Types of Muscle Action Static Action Dynamic Action Factors Influencing Muscle Action Joint Angle Muscle Cross-Sectional Area Speed of Movement Muscle Fibre Type Age Sex Kinesiology Books Publisher 2 TYPES OF MUSCLE ACTION Static Action-Not moving Dynamic Action > - moving Kinesiology Books Publisher 3 · both can generate force 4 Kinesiology Books Publisher 4 STATIC ACTION Isometric Iso = same, metric = length movement - generate force with no > - Only Strengthen the point of the angle you are on · Kinesiology Books Publisher 5 DYNAMIC ACTION Inte rn Forc al Exte e rn forc al e Obje Mus c weig ct forc le ht e Kinesiology Books Publisher 6 CONCENTRIC ACTION force then the resistance force - generating more muscle - when we generate force our Shortens - mimic life movement - lack muscle soreness Kinesiology Books Publisher 7 ECCENTRIC ACTION -> Muscle lengthens Muscle force is - less then the resistance force later - soreness happen two days 8 Kinesiology Books Publisher 8 ISOKINETIC ACTION Iso = same, kinetic = motion - Not seen very often - Requires specialized equipment > - you are able to overload the muscle regardless of the Joint angle - does not mimic life movement - think hydraulics 9 Kinesiology Books Publisher 9 PLYOMETRIC ACTION A sudden eccentric loading and muscle stretching followed by a strong concentric contraction movement - very athletic - bounding or Jumping movement - Rapid eccentric action followed by concentric movement - activates a stretch reflex - use the elasticity of your muscle - most sports use the stretch 10 Kinesiology Books Publisher 10 FACTORS INFLUENCING MUSCLE ACTION Joint Angle -how much force ↳ better can angle of be pull generated Muscle Cross-Sectional Area Speed of Movement Muscle Fibre Type Age Sex Kinesiology Books Publisher 11 JOINT ANGLE Different muscle pulling efficiency and strength production ↳ : how much force you can generate · Angle of pull Kinesiology Books Publisher 12 MUSCLE CROSS-SECTIONAL AREA Strength is determined by lean body mass volume ↳ fat is not a body mass · more force generation Kinesiology Books Publisher 13 MAXIMAL OR ABSOLUTE STRENGTH may ↳ one rep More muscle · = more force 14 Kinesiology Books Publisher 14. 15 Kinesiology Books Publisher 15 RELATIVE STRENGTH ↳. Maximal strength divided by your body mass 16 Kinesiology Books Publisher 16 SPEED OF MOVEMENT Linked to : Maximal strength Power · faster you move the less force you can generate ② Kinesiology Books Publisher 17  18 often moving fast can benefit you Kinesiology Books Publisher 18 MAXIMAL STRENGTH ↳) I rep max 19 Kinesiology Books Publisher 19  20 Kinesiology Books Publisher 20 POWER · combined of speed and strength e. G Olympic lifting · explosive strength · overcoming resistants quickly 21 Kinesiology Books Publisher 21 MUSCULAR ENDURANCE ability to submaximal force repeatedly over time · generate a 22 Kinesiology Books Publisher 22 MAXIMAL STRENGTH & POWER ­ strength = ­ power ­ strength = ­ acceleration f = m a a = higher strength higher acceleration · more force · More strength = 23 Kinesiology Books Publisher 23 MAXIMAL STRENGTH & ENDURANCE ­ force required = ¯ repetitions possible As intensity goes up duration down (vice versa) · your , goes 24 Kinesiology Books Publisher 24 STRENGTH & ENDURANCE ISSUES Strength development can enhance endurance Endurance training might inhibit strength ↳. Endurance training health benefits outweigh strength health benefits 25 Kinesiology Books Publisher 25 MUSCLE FIBRE TYPE ­ FT content = ­ force output, speed of contraction and ¯ endurance ­ ST content = ¯ force output, speed of contraction and ­ endurance · Look at athletes Kinesiology Books Publisher 26 AGE ­ Age = ¯ FT number apoptosis Sacropenia muse · decreased force with age ↳ cause them to fall Kinesiology Books Publisher 27  Independence Lose ability with · age · the muscle mass you have more now will benefit you later Kinesiology Books Publisher 28 SEX Average woman = 70% of man’s strength Kinesiology Books Publisher 29 STRENGTH-TO-WEIGHT RATIO Total body mass Women < men Lean body mass composition Women = men · same type of muscle tissue but men have more 30 Kinesiology Books Publisher 30 MUSCLE CROSS-SECTIONAL AREA Women < men ↳More st muscle ↳ more FT Muscle fibers Fibers 31 Kinesiology Books Publisher 31 TESTOSTERONE Anabolic hormone ↳ men have more testosterone which allows more muscle strength 32 Kinesiology Books Publisher 32 PUTTING IT ALL TOGETHER Muscle contraction can be classified as static or dynamic, and eccentric, concentric, and isometric Strength is the highest load one can lift; power is the ability to overcome resistance with high rate of muscular contraction; endurance is the ability to resist muscle fatigue Factors affecting muscle force ad power include joint angle, muscle area, speed of movement, fibre type, age and sex Kinesiology Books Publisher 33