Lecture 16 - Biomechanics of Fitness

Question 1

what are the 5 goals of physical fitness?

Answer 1

• increase muscle strength (force)
• increase muscle power (force and velocity)
• increase flexibility (ROM)
• increase cardiovascular endurance (whole body)
• increase local muscular endurance (part of body)

Question 2

what is resistance training?

Answer 2

• application of external loads on parts of the body against which the subject moves
• lifting heavy things –> working against gravity (cables allow you to work against gravity on different planes)

Question 3

what are the 6 ways resistance can be applied to the body?

Answer 3

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

Question 4

what are free weights?

Answer 4

• dumbbells, barbels, kettle bells, etc.
• simple and inexpensive
• weight is constant throughout the movement
• requires control and stability (so less weight can be lifted in comparison to machines)

Question 5

what muscles are being worked during free weight training?

Answer 5

• agonists
• antagonists
• concentric and eccentric muscles
• stabilizers

Question 6

what are gravity resistance machines?

Answer 6

• cables
• limit the motion of the weight to only one or two degrees of freedom
• safer than free weights because you don’t need as much control
• remove the need for stabilization
• less likely to have proper form

Question 7

what are variable weight machines?

Answer 7

• change the resistance during the range of motion
• ‘even out’ the length-tension curve (more resistance at optimal length, less when muscle is close to insufficiency)
• kidney bean/egg shaped cables to change force through ROM –> changes torque/lever arm

Question 8

what are isokinetic machines?

Answer 8

• use an electric motor to force joint motion to occur at a fixed angular speed
• isokinetic dynamometer

Question 9

what are programmable machines?

Answer 9

• very common
• on-board computer controls the force and speed of the workout over a length of time
• like an elliptical (can change the resistance etc.)

Question 10

what are the 3 ways you can measure muscle strength?

Answer 10

• isometric = muscle stays the same length
• isokinetic = muscle changes length at a constant speed
• isotonic = muscle maintains a constant force

Question 11

how do you measure isometric strength?

Answer 11

• measuring the max force produced by a muscle (MVC/ maximum voluntary contraction)
• compared to MIVC (maximum involuntary contraction) which is slightly larger and induced with electrical stimulation (this is painful)

Question 12

how can you measure isokinetic strength?

Answer 12

• controlled by an isokinetic dynamometer
• quantify exercise –> ensures compliance

Question 13

how can you measure isotonic strength?

Answer 13

• trained with resistance training
• muscles are producing nearly constant force during the rep (weight doesn’t change)

Question 14

what is the goal of muscle power?

Answer 14

• to increase both speed and strength (like power lifting)

Question 15

what is muscle endurance? how do you train it?

Answer 15

• regulated by the cardiovascular system
• heart and lungs get more effective with training
• local muscle endurance improves as vascularization improves

Question 16

what is flexibility?

Answer 16

• amount of ROM you have at a joint
• active = ROM of forceful joint motion
• passive = ROM the joint can move
• passive is always larger