Lab 9: Strength Training

Question 1

Types of Muscle Contractions

Answer 1

• Isometric
• Concentric
• Eccentric

Question 2

Isometric Contraction

Answer 2

Muscle contracts but does
not change length

Question 3

Concentric Contraction

Answer 3

Muscle shortens during
contraction

Question 4

Eccentric Contraction

Answer 4

Muscle lengthens during
contraction

Question 5

Force Production

Answer 5

The amount of force generated during muscular contraction

Question 6

What is force production dependent on?

Answer 6

• Type(s) of motor units recruited
• Number of motor units recruited
• Initial muscle length
• The nature of the motor units’ stimulation

Question 7

Which type of contraction produces the highest amount of force?

Answer 7

• Eccentric
• Isometric
• Concentric
  (energy expenditure is the opposite so highest from bottom to top)

Question 8

What equipment do we use?

Answer 8

Biodex Dynamometer

Question 9

Purpose of Isometric Strength Testing

Answer 9

• Ability to isolate a muscle group to determine strength/weakness
• Assess changes in strength after training program
• Assess mobility and muscle strength of individuals with orthopedic problems

Question 10

Measuring Force Production

Answer 10

• Greater ability to produce force = greater function of the muscle
• Loss of function results in the inability to perform activities of daily living (ADLs) - very crucial for older adults Strength Testing

Question 11

Lab Instructions

Answer 11

• Perform 4 sets of a maximal quadriceps contraction
• Knee held at 60 degrees flexion (isometric contraction)
• 90 seconds of rest in between sets

Question 12

What are we looking for in the results?

Answer 12

• Consistent results; there should not be more than a 10% variation in
  force production between sets.
• Plateau of maximal contraction force with each set Strength Testing