Lecture #8 (Muscular Strength and Endurance) Flashcards
What is an isometric activity?
A muscle contraction and tension without a change in a muscles length
When are isometrics used during rehab?
When trying to protect a healing joint from stress or in a very weak or inhibited muscle because they do not produce a lot of joint stress (so they are good right after surgery). These are used as a way to combat atrophy and kind of serve as a filler right after an injury.
Where do isometric contractions help strength gains?
Limited to within 20 degrees of where the contraction is performed–so they should be
How long does it take an isometric contraction so reach 50% of a full muscular contraction?
10 seconds…so it is not necessary to hold isometrics for more than 5-10 seconds
What percentage of effort can strength gains be made with isometric exercises?
35-100% of effort…35-66% the gains are very slow but 67-100% the gains are higher. In fact, with 67-100% of effort, strength can be gained by as much as 5-12% per week.
How fast is strength lost due to immobilization?
8% per week to 5% per day
What is dynamic activity divided into?
Isotonic and isokinetic activity
What is static activity?
Isometric activity
What are the subcategories of isotonic activity?
Concentric or eccentric
Which is a higher force, eccentric or concentric? Which causes more muscle soreness?
Eccentric
When a muscle is significantly weak and/or actively healing, what types of exercises should be avoided to reduce the intensity of soreness form the exercise routines?
Eccentrics–but they must be included later in rehab to better replicate sport activities
What is the strength of a muscle or group?
The greatest amount of tension created isotonically at the weakest point of the muscle
What is isokinetic activity?
Concentric contractions at a controlled rate…usually measured in degrees / sec. Also, the muscle forces varies thoughout the ROM as the part is moved at the same speed
What is isokinetic activity called?
Accomodating resistance…where the patient’s force is greatest so is the resistance from the machine as the resistance is dependent on the force placed on it (since the speed won’t change)
What are open chain exercises?
The distal segment is moving freely in space
What are closed chain exercises?
The distal segment is fixed and not moving freely in space
OKC or CKC?? Which is usually higher velocity and higher in joint stress? Which is usually used early in rehab because they decrease shear force and joint stress?
Higher velocity/ stress = OKC
Early in rehab/ decrease force = CKC
True or false:
In OKC, no part of the chain can move independently from the others.
False–this is true of CKC.
What are the advantages of OKC? (x6)
- can start to do strengthening even if pt has WB restrictions
- can isolate and focus on one muscle
- requires less strength to perform
- resistance can be more variable
- less substitution by other stronger muscles
- easier to instruct and do correctly
What are the advantages of CKC? (x4)
- functional movements (mimic sport motions)
- exercises the entire kinetic chain (stabilizers,multiple muscles, and trains for stability, balance, coordination, and agility)
- more difficult to complete so it requires more strength in general
- decreased shear forces on the joints