(2) Lecture 16: Biomechanics of Fitness

Question 1

Goals of Physical Fitness

Answer 1

1. ↑ muscle strength (force)
2. ↑ muscle power (force and velocity)
   3.↑ flexibility (ROM)
3. ↑CV endurance (total body)
   - enlarging heart, capacity of lungs, speed of O2 transfer
4. increase local muscular endurance (part of body)
   - LOSE IT AS SOON AS YOU STOP DOING IT

Question 2

Ways to apply resistance to body

Answer 2

• free weights
• body weight positions
• gravity resistance machines
• variable weights
• isokinetic machines
• programmable machines

Question 3

Free weight

Answer 3

• dumbbells, barbells, kettlebells
• weight is constant throughout movement
• requires more CONTROL by lifter

body orientation must be adjusted to control direction of weight’s resistance

Question 4

Body weight resistance

Answer 4

Changing positions changes muscles exercised

Question 5

Gravity resistance

Answer 5

• limit motion of weight to only ONE or TWO degrees of freedom
• safer than free weights b/c you don’t need as much control
• difficult to get proper form

Question 6

Variable weights

Answer 6

• change resistance during ROM
• done to “EVEN OUT” LENGTH-TENSION CURVE (ex. more resistance when muscle is optimal length + less when it is too long/short)

All about balancing TORQUES NOT WEIGHTS (Easter egg - more force when muscle length is optimal)

Question 7

Isokinetic dynamometer

Answer 7

forces joint motion to occur at a fixed angular speed

Question 8

Muscle strength

Answer 8

Measured in 3 ways
- isometric
- isokinetic
- isotonic

Question 9

Isometric muscle strength

Answer 9

muscle stays same LENGTH (most easily measured)

• Maximum voluntary contraction (MVC): max force produced by muscle
• Maximum involuntary contraction (MIVC): a bit larger than MVC and induced w/ electrical stimulation

Question 10

Isokinetic muscle strength

Answer 10

muscle changes length at CONSTANT SPEED (controlled by dynamometer)

• Useful way to QUANTIFY exercise
• Useful for prehab and ensures compliance

Question 11

Isotonic muscle strength

Answer 11

muscle maintains CONSTANT FORCE (what you are training w/ resistance training)

Weight does NOT change = muscles produce nearly constant force during rep

Question 12

Muscle power

Answer 12

increases BOTH strength and speed

Question 13

Muscle endurance

Answer 13

Regulated by CV system (as endurance, ↑ heart and lungs get larger + more efficient)

• Local muscle endurance improves as vasculature and storage capability of specific muscle increases → muscle or muscle group gets larger and more efficient

Ex. training to do multiple chin ups

Question 14

Flexibility

Answer 14

amount of ROM you have at a joint

Active flexibility: ROM through which you can perform FORCEFUL joint motion

Passive flexibility: ROM that the joint can move (someone will help + always MORE)