CSEP-Certified Certified Personal Trainer (CSEP-CPT) CPT) Musculoskeletal Fitness Theory

Transcription

1 CSEP-Certified Certified Personal Trainer (CSEP-CPT) CPT) Musculoskeletal Fitness Theory 1

2 Basic Anatomy Key Concepts:

3 Force & Levers 1 st class» seesaw» muscles that extend neck R F AF 2 nd class» loaded wheelbarrow» plantar flexion» force at the expense of speed & distance 3 rd class» flexion at elbow» speed & distance at the expense of force F R AF AF R F 3

4 Fascicle Organization 4

5 Parallel Muscles Fascicles are parallel to long axis Most muscles in body Functional characteristics similar to individual m. fibre Entire m. shortens by same amount 5

6 Convergent muscles Fibres come together (spread out) to a common attachment site Ex: pectoralis major m. Direction of pull can be changed by stimulating different fibres of m. Less strength than parallel m. of same size 6

7 Pennate M. 1+ tendons run through body of muscles & fascicles form an oblique angle to tendon Contain more m. fibres than a parallel m. of same size generates tension» Unipennate» Bipennate» Multipennate 7

8 Primary Actions Prime mover (agonist)» Contraction is responsible for movement Synergist» Assists prime mover Antagonist» Oppose action of agonist» Tension adjusted to control speed of agonist 9

9 Assessment of Muscular Strength Key Concepts:

10 Definitions Muscular strength: peak force or torque developed during a maximal voluntary contraction (MVC) Muscular power: rate at which mechanical work is performed» Maximal amount of force one can exert in the least amount of time (force/time) Muscular endurance: ability to exert sub-maximal force repeatedly, or sustain a static contraction without fatigue 11

11 Force Generation Ability of a muscle or muscle group to generate force depends on» Size of muscle» Type of contraction» Number of muscle fibres activated» Ability of nervous system to activate muscle fibres» MOTIVATION of the client! Strength potential is limited by genetics» Number of fast-twitch fibres 12

12 Why Test Strength & Power? To develop profile of client To monitor training progress To monitor the rehabilitation of injuries To assess health status???? 13

13 Gender & Aging Men typically have greater muscle mass and cross-sectional area than women Rate and pattern of strength development and decline in age are similar for both genders Peak strength: females late teens and males during their 20s. 14

14 Gender & Aging: Strength Decline in strength begins at age 45 to 50 and progresses at a rate of 12-15% per decade 25-40% of muscular strength is lost by the 6 th or 7 th decade Large portion of the decreased strength in old age is due to muscle atrophy Women tend to have a higher percentage loss of strength than men 15

15 Gender & Aging: Strength Grip Strength: Good indication of overall muscular strength» Early screening of populations to identify those at higher risk for physical disability related to low muscle strength» Cutoff score of 21.0 kg minimum level of old-age grip strength» Individuals with scores close to this value are 8X the risk of developing muscular strength disabilities» Good indicator of high and low levels of health status - Warburton et al. Can J Appl Physiol 26(2): , Warburton et al. Can J Appl Physiol 26(2): ,

16 Theoretical relationship between musculoskeletal fitness and independence across the lifespan. Musculoskeletal Fitness Independent Living Threshold for Dependence Disability Age (yr) Warburton et al. CMAJ

17 Gender & Aging: Muscular Endurance Loss in endurance with aging is also significant Peak partial curl-up scores: yr Peak back extensor endurance scores: yr Average performance for endurance tests (push-ups, partial curl-ups and back extensor endurance) decline dramatically through to yr range 18

18 Gender & Aging: Muscular Endurance Push-ups and partial curl-ups are less significant predictors of overall musculoskeletal health in comparison to grip strength for both genders Males: Push-ups and grip strength are the strongest discriminators between high and low health Females: Grip strength and sit & reach are the strongest discriminators between high and low health» Payne et al. Can J Appl Physiol 25(2): ,

19 Gender & Aging: Power Greater loss in power with aging compared to muscular strength & endurance Maybe due to the loss in FT fibres Women have lower leg extensor power than men Gender differences begin in the teens and continue throughout life 20

20 Musculoskeletal Fitness in MSF with age is not solely due to age itself but to physical inactivity and/or chronic disease Strength training can offset the loss in muscular strength and muscle mass associated with aging Improves the ability to perform activities of daily living, improve bone health and reduce the risk of falling 21

21 Strength Testing When choosing a strength test consider:» Client s goals» Specificity» Equipment» Upper & lower body strength measure, and abdominal endurance Always ensure subject is warmed up & familiar with all equipment Keep motivation consistent!!!! 22

22 Absolute or Relative Strength? Absolute strength = MVC (in Newtons or kg) MVC = maximum voluntary contraction Relative strength = MVC / body mass 23

23 Isotonic Contractions Concentric contraction» Muscle shortens during tension development» Weight is lifted Eccentric contraction» Muscle lengthens during tension development» Weight is lowered» Able to generate higher forces» Greater risk for injury What is the maximal weight that can be lifted during a concentric contraction? 24

24 1-RM Maximal amount that can be lifted in one complete repetition with proper technique Can be used to rate health status, establish exercise prescription workloads, and/or monitor a resistance training program Limitations of 1-RM test» Injury» Technique» Economy of test Outside of the Scope of Practice of a CSEP-CPT! CPT! 25

25 Predicting 1-RM1 Muscular endurance is directly related to muscular strength THEREFORE, 1-RM can be predicted without performing a maximal lift Usually 6 to 10-RM test 26

26 Submaximal Predicted 1-RM1 Single Set Warm up at 40-60% of estimated 1-RM for 5-10 reps Stretch during 1 min rest period 1 set of 10 reps at 60-80% of estimated 1-RM» >10 reps completed, then client gets a 3-5 min rest Increase weight client attempts up to 10 reps 27

27 Predicted 1-RM 1 (Baechle & Earle) determine %1-RM from # of reps completed divide weight lifted by % 1-RM EXAMPLE: client performed 8 repetitions of 100 lbs 8 repetitions = 80% 1-RM 1-RM = 100 lbs lifted/.80 1-RM = 125 lbs Reps % 1-RM Completed

28 PRACTICE! Groups of person client; 1 acts as appraiser; 1 observes Calculate results for different muscle groups 29

29 Muscle Balance A strength imbalance between opposing muscle groups may compromise joint stability & increase risk of injury Muscle balance ratios differ between muscle groups Crude index can be obtained by comparing 1-RM Muscle Groups Ratio Hip extensors/ flexors 1:1 Elbow extensors/ flexors 1:1 Trunk extensors/ flexors 1:1 Ankle inverters/ everters 1:1 Shoulder flexors/ extensors 2:3 Knee extensors/ flexors 3:2 Shoulder internal/ external rotators 3:2 Plantarflexion/ dorsiflexion 3:1 Strength Comparison Right & left side 10-15% Upper to lower body 40-60% 30

30 Sources of Error Client Equipment Technician Skill Environment 31

31 Exercise Prescription for Improving Muscular Strength & Endurance Key Concepts:

32 Key Training Principles Specificity principle» Strength improvements are specific to the muscle group trained Progressive overload principle» Achieved by changing INTENSITY, duration, frequency, recovery 33

33 Flexibility Key Concepts:

34 Flexibility Ability of a joint (or series of joints) to move through a full ROM» Specific to the joint» Dependent on morphological factors» Ball-and-socket joints (hip/shoulder) have greater flexibility than hinge joints (elbow/knee)» Muscle-tendon factors can impact flexibility» Also related to age & type of activity performed 35

35 Assessment Direct methods» Goniometer, Leighton flexometer Indirect methods» Linear measurements - i.e., sit and reach Pros/cons of each? All flexibility measurements are dependent on the skill of the fitness appraiser! 36

36 Benefits of Adequate Flexibility Improved performance (?) Helps with proper posture Reduces stiffness and soreness from unaccustomed activity Minimizes risk of back injury 37

37 Types of Stretching Ballistic - bouncing and jerking movements at extreme ROM or point of discomfort» bad bad bad» remember the muscle spindle! Static positions - position is held for a period of time at extreme ROM Partner Assisted (Proprioceptive neuromuscular facilitation (PNF)) - induces muscle relaxation through spinal reflex mechanisms» remember the GTO & reciprocal inhibition! 38

38 PNF Contract-relax method based on reciprocal inhibition» Isometric contraction of antagonist - Induces a reflex facilitation & contraction of agonist suppresses the contractile activity in the antagonist during static stretch phase - Also, stimulates Golgi tendon organs reflex relaxation of same muscle group 39

39 Partner-Assisted Technique Contract-relax Stretch muscle Isometric contraction of muscle group being stretched (5-6 s) Slow static stretch (10-30 sec) 40

40 CPAFLA Stretching Routine Tips Stretch slowly and smoothly Avoid bouncing and jerking Use gentle continuous movement or stretchand-hold techniques Breathe naturally Static stretching - start with several reps of 10-30s hold and then progress to fewer reps and longer duration Avoid exercises that hurt or feel wrong 41